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Diffstat (limited to 'generic/tclIORChan.c')
| -rw-r--r-- | generic/tclIORChan.c | 3238 |
1 files changed, 3238 insertions, 0 deletions
diff --git a/generic/tclIORChan.c b/generic/tclIORChan.c new file mode 100644 index 0000000..94428bb --- /dev/null +++ b/generic/tclIORChan.c @@ -0,0 +1,3238 @@ +/* + * tclIORChan.c -- + * + * This file contains the implementation of Tcl's generic channel + * reflection code, which allows the implementation of Tcl channels in + * Tcl code. + * + * Parts of this file are based on code contributed by Jean-Claude + * Wippler. + * + * See TIP #219 for the specification of this functionality. + * + * Copyright (c) 2004-2005 ActiveState, a divison of Sophos + * + * See the file "license.terms" for information on usage and redistribution of + * this file, and for a DISCLAIMER OF ALL WARRANTIES. + */ + +#include "tclInt.h" +#include "tclIO.h" +#include <assert.h> + +#ifndef EINVAL +#define EINVAL 9 +#endif +#ifndef EOK +#define EOK 0 +#endif + +/* + * Signatures of all functions used in the C layer of the reflection. + */ + +static int ReflectClose(ClientData clientData, + Tcl_Interp *interp); +static int ReflectInput(ClientData clientData, char *buf, + int toRead, int *errorCodePtr); +static int ReflectOutput(ClientData clientData, const char *buf, + int toWrite, int *errorCodePtr); +static void ReflectWatch(ClientData clientData, int mask); +static int ReflectBlock(ClientData clientData, int mode); +#ifdef TCL_THREADS +static void ReflectThread(ClientData clientData, int action); +#endif +static Tcl_WideInt ReflectSeekWide(ClientData clientData, + Tcl_WideInt offset, int mode, int *errorCodePtr); +static int ReflectSeek(ClientData clientData, long offset, + int mode, int *errorCodePtr); +static int ReflectGetOption(ClientData clientData, + Tcl_Interp *interp, const char *optionName, + Tcl_DString *dsPtr); +static int ReflectSetOption(ClientData clientData, + Tcl_Interp *interp, const char *optionName, + const char *newValue); + +/* + * The C layer channel type/driver definition used by the reflection. This is + * a version 3 structure. + */ + +static const Tcl_ChannelType tclRChannelType = { + "tclrchannel", /* Type name. */ + TCL_CHANNEL_VERSION_5, /* v5 channel */ + ReflectClose, /* Close channel, clean instance data */ + ReflectInput, /* Handle read request */ + ReflectOutput, /* Handle write request */ + ReflectSeek, /* Move location of access point. NULL'able */ + ReflectSetOption, /* Set options. NULL'able */ + ReflectGetOption, /* Get options. NULL'able */ + ReflectWatch, /* Initialize notifier */ + NULL, /* Get OS handle from the channel. NULL'able */ + NULL, /* No close2 support. NULL'able */ + ReflectBlock, /* Set blocking/nonblocking. NULL'able */ + NULL, /* Flush channel. Not used by core. NULL'able */ + NULL, /* Handle events. NULL'able */ + ReflectSeekWide, /* Move access point (64 bit). NULL'able */ +#ifdef TCL_THREADS + ReflectThread, /* thread action, tracking owner */ +#else + NULL, /* thread action */ +#endif + NULL /* truncate */ +}; + +/* + * Instance data for a reflected channel. =========================== + */ + +typedef struct { + Tcl_Channel chan; /* Back reference to generic channel + * structure. */ + Tcl_Interp *interp; /* Reference to the interpreter containing the + * Tcl level part of the channel. NULL here + * signals the channel is dead because the + * interpreter/thread containing its Tcl + * command is gone. + */ +#ifdef TCL_THREADS + Tcl_ThreadId thread; /* Thread the 'interp' belongs to. == Handler thread */ + Tcl_ThreadId owner; /* Thread owning the structure. == Channel thread */ +#endif + Tcl_Obj *cmd; /* Callback command prefix */ + Tcl_Obj *methods; /* Methods to append to command prefix */ + Tcl_Obj *name; /* Name of the channel as created */ + + int mode; /* Mask of R/W mode */ + int interest; /* Mask of events the channel is interested + * in. */ + + int dead; /* Boolean signal that some operations + * should no longer be attempted. */ + + /* + * Note regarding the usage of timers. + * + * Most channel implementations need a timer in the C level to ensure that + * data in buffers is flushed out through the generation of fake file + * events. + * + * See 'rechan', 'memchan', etc. + * + * Here this is _not_ required. Interest in events is posted to the Tcl + * level via 'watch'. And posting of events is possible from the Tcl level + * as well, via 'chan postevent'. This means that the generation of all + * events, fake or not, timer based or not, is completely in the hands of + * the Tcl level. Therefore no timer here. + */ +} ReflectedChannel; + +/* + * Structure of the table maping from channel handles to reflected + * channels. Each interpreter which has the handler command for one or more + * reflected channels records them in such a table, so that 'chan postevent' + * is able to find them even if the actual channel was moved to a different + * interpreter and/or thread. + * + * The table is reachable via the standard interpreter AssocData, the key is + * defined below. + */ + +typedef struct { + Tcl_HashTable map; +} ReflectedChannelMap; + +#define RCMKEY "ReflectedChannelMap" + +/* + * Event literals. ================================================== + */ + +static const char *const eventOptions[] = { + "read", "write", NULL +}; +typedef enum { + EVENT_READ, EVENT_WRITE +} EventOption; + +/* + * Method literals. ================================================== + */ + +static const char *const methodNames[] = { + "blocking", /* OPT */ + "cget", /* OPT \/ Together or none */ + "cgetall", /* OPT /\ of these two */ + "configure", /* OPT */ + "finalize", /* */ + "initialize", /* */ + "read", /* OPT */ + "seek", /* OPT */ + "watch", /* */ + "write", /* OPT */ + NULL +}; +typedef enum { + METH_BLOCKING, + METH_CGET, + METH_CGETALL, + METH_CONFIGURE, + METH_FINAL, + METH_INIT, + METH_READ, + METH_SEEK, + METH_WATCH, + METH_WRITE +} MethodName; + +#define FLAG(m) (1 << (m)) +#define REQUIRED_METHODS \ + (FLAG(METH_INIT) | FLAG(METH_FINAL) | FLAG(METH_WATCH)) +#define NULLABLE_METHODS \ + (FLAG(METH_BLOCKING) | FLAG(METH_SEEK) | \ + FLAG(METH_CONFIGURE) | FLAG(METH_CGET) | FLAG(METH_CGETALL)) + +#define RANDW \ + (TCL_READABLE | TCL_WRITABLE) + +#define IMPLIES(a,b) ((!(a)) || (b)) +#define NEGIMPL(a,b) +#define HAS(x,f) (x & FLAG(f)) + +#ifdef TCL_THREADS +/* + * Thread specific types and structures. + * + * We are here essentially creating a very specific implementation of 'thread + * send'. + */ + +/* + * Enumeration of all operations which can be forwarded. + */ + +typedef enum { + ForwardedClose, + ForwardedInput, + ForwardedOutput, + ForwardedSeek, + ForwardedWatch, + ForwardedBlock, + ForwardedSetOpt, + ForwardedGetOpt, + ForwardedGetOptAll +} ForwardedOperation; + +/* + * Event used to forward driver invocations to the thread actually managing + * the channel. We cannot construct the command to execute and forward that. + * Because then it will contain a mixture of Tcl_Obj's belonging to both the + * command handler thread (CT), and the thread managing the channel (MT), + * executed in CT. Tcl_Obj's are not allowed to cross thread boundaries. So we + * forward an operation code, the argument details, and reference to results. + * The command is assembled in the CT and belongs fully to that thread. No + * sharing problems. + */ + +typedef struct ForwardParamBase { + int code; /* O: Ok/Fail of the cmd handler */ + char *msgStr; /* O: Error message for handler failure */ + int mustFree; /* O: True if msgStr is allocated, false if + * otherwise (static). */ +} ForwardParamBase; + +/* + * Operation specific parameter/result structures. (These are "subtypes" of + * ForwardParamBase. Where an operation does not need any special types, it + * has no "subtype" and just uses ForwardParamBase, as listed above.) + */ + +struct ForwardParamInput { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + char *buf; /* O: Where to store the read bytes */ + int toRead; /* I: #bytes to read, + * O: #bytes actually read */ +}; +struct ForwardParamOutput { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + const char *buf; /* I: Where the bytes to write come from */ + int toWrite; /* I: #bytes to write, + * O: #bytes actually written */ +}; +struct ForwardParamSeek { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + int seekMode; /* I: How to seek */ + Tcl_WideInt offset; /* I: Where to seek, + * O: New location */ +}; +struct ForwardParamWatch { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + int mask; /* I: What events to watch for */ +}; +struct ForwardParamBlock { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + int nonblocking; /* I: What mode to activate */ +}; +struct ForwardParamSetOpt { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + const char *name; /* Name of option to set */ + const char *value; /* Value to set */ +}; +struct ForwardParamGetOpt { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + const char *name; /* Name of option to get, maybe NULL */ + Tcl_DString *value; /* Result */ +}; + +/* + * Now join all these together in a single union for convenience. + */ + +typedef union ForwardParam { + ForwardParamBase base; + struct ForwardParamInput input; + struct ForwardParamOutput output; + struct ForwardParamSeek seek; + struct ForwardParamWatch watch; + struct ForwardParamBlock block; + struct ForwardParamSetOpt setOpt; + struct ForwardParamGetOpt getOpt; +} ForwardParam; + +/* + * Forward declaration. + */ + +typedef struct ForwardingResult ForwardingResult; + +/* + * General event structure, with reference to operation specific data. + */ + +typedef struct ForwardingEvent { + Tcl_Event event; /* Basic event data, has to be first item */ + ForwardingResult *resultPtr; + ForwardedOperation op; /* Forwarded driver operation */ + ReflectedChannel *rcPtr; /* Channel instance */ + ForwardParam *param; /* Packaged arguments and return values, a + * ForwardParam pointer. */ +} ForwardingEvent; + +/* + * Structure to manage the result of the forwarding. This is not the result of + * the operation itself, but about the success of the forward event itself. + * The event can be successful, even if the operation which was forwarded + * failed. It is also there to manage the synchronization between the involved + * threads. + */ + +struct ForwardingResult { + Tcl_ThreadId src; /* Originating thread. */ + Tcl_ThreadId dst; /* Thread the op was forwarded to. */ + Tcl_Interp *dsti; /* Interpreter in the thread the op was + * forwarded to. */ + /* + * Note regarding 'dsti' above: Its information is also available via the + * chain evPtr->rcPtr->interp, however, as can be seen, two more + * indirections are needed to retrieve it. And the evPtr may be gone, + * breaking the chain. + */ + Tcl_Condition done; /* Condition variable the forwarder blocks + * on. */ + int result; /* TCL_OK or TCL_ERROR */ + ForwardingEvent *evPtr; /* Event the result belongs to. */ + ForwardingResult *prevPtr, *nextPtr; + /* Links into the list of pending forwarded + * results. */ +}; + +typedef struct ThreadSpecificData { + /* + * Table of all reflected channels owned by this thread. This is the + * per-thread version of the per-interpreter map. + */ + + ReflectedChannelMap *rcmPtr; +} ThreadSpecificData; + +static Tcl_ThreadDataKey dataKey; + +/* + * List of forwarded operations which have not completed yet, plus the mutex + * to protect the access to this process global list. + */ + +static ForwardingResult *forwardList = NULL; +TCL_DECLARE_MUTEX(rcForwardMutex) + +/* + * Function containing the generic code executing a forward, and wrapper + * macros for the actual operations we wish to forward. Uses ForwardProc as + * the event function executed by the thread receiving a forwarding event + * (which executes the appropriate function and collects the result, if any). + * + * The ExitProc ensures that things do not deadlock when the sending thread + * involved in the forwarding exits. It also clean things up so that we don't + * leak resources when threads go away. + */ + +static void ForwardOpToHandlerThread(ReflectedChannel *rcPtr, + ForwardedOperation op, const void *param); +static int ForwardProc(Tcl_Event *evPtr, int mask); +static void SrcExitProc(ClientData clientData); + +#define FreeReceivedError(p) \ + if ((p)->base.mustFree) { \ + ckfree((p)->base.msgStr); \ + } +#define PassReceivedErrorInterp(i,p) \ + if ((i) != NULL) { \ + Tcl_SetChannelErrorInterp((i), \ + Tcl_NewStringObj((p)->base.msgStr, -1)); \ + } \ + FreeReceivedError(p) +#define PassReceivedError(c,p) \ + Tcl_SetChannelError((c), Tcl_NewStringObj((p)->base.msgStr, -1)); \ + FreeReceivedError(p) +#define ForwardSetStaticError(p,emsg) \ + (p)->base.code = TCL_ERROR; \ + (p)->base.mustFree = 0; \ + (p)->base.msgStr = (char *) (emsg) +#define ForwardSetDynamicError(p,emsg) \ + (p)->base.code = TCL_ERROR; \ + (p)->base.mustFree = 1; \ + (p)->base.msgStr = (char *) (emsg) + +static void ForwardSetObjError(ForwardParam *p, Tcl_Obj *objPtr); + +static ReflectedChannelMap * GetThreadReflectedChannelMap(void); +static void DeleteThreadReflectedChannelMap(ClientData clientData); + +#endif /* TCL_THREADS */ + +#define SetChannelErrorStr(c,msgStr) \ + Tcl_SetChannelError((c), Tcl_NewStringObj((msgStr), -1)) + +static Tcl_Obj * MarshallError(Tcl_Interp *interp); +static void UnmarshallErrorResult(Tcl_Interp *interp, + Tcl_Obj *msgObj); + +/* + * Static functions for this file: + */ + +static int EncodeEventMask(Tcl_Interp *interp, + const char *objName, Tcl_Obj *obj, int *mask); +static Tcl_Obj * DecodeEventMask(int mask); +static ReflectedChannel * NewReflectedChannel(Tcl_Interp *interp, + Tcl_Obj *cmdpfxObj, int mode, Tcl_Obj *handleObj); +static Tcl_Obj * NextHandle(void); +static void FreeReflectedChannel(ReflectedChannel *rcPtr); +static int InvokeTclMethod(ReflectedChannel *rcPtr, + MethodName method, Tcl_Obj *argOneObj, + Tcl_Obj *argTwoObj, Tcl_Obj **resultObjPtr); + +static ReflectedChannelMap * GetReflectedChannelMap(Tcl_Interp *interp); +static void DeleteReflectedChannelMap(ClientData clientData, + Tcl_Interp *interp); +static int ErrnoReturn(ReflectedChannel *rcPtr, Tcl_Obj *resObj); + +/* + * Global constant strings (messages). ================== + * These string are used directly as bypass errors, thus they have to be valid + * Tcl lists where the last element is the message itself. Hence the + * list-quoting to keep the words of the message together. See also [x]. + */ + +static const char *msg_read_toomuch = "{read delivered more than requested}"; +static const char *msg_write_toomuch = "{write wrote more than requested}"; +static const char *msg_write_nothing = "{write wrote nothing}"; +static const char *msg_seek_beforestart = "{Tried to seek before origin}"; +#ifdef TCL_THREADS +static const char *msg_send_originlost = "{Channel thread lost}"; +static const char *msg_send_dstlost = "{Owner lost}"; +#endif /* TCL_THREADS */ +static const char *msg_dstlost = "-code 1 -level 0 -errorcode NONE -errorinfo {} -errorline 1 {Owner lost}"; + +/* + * Main methods to plug into the 'chan' ensemble'. ================== + */ + +/* + *---------------------------------------------------------------------- + * + * TclChanCreateObjCmd -- + * + * This function is invoked to process the "chan create" Tcl command. + * See the user documentation for details on what it does. + * + * Results: + * A standard Tcl result. The handle of the new channel is placed in the + * interp result. + * + * Side effects: + * Creates a new channel. + * + *---------------------------------------------------------------------- + */ + +int +TclChanCreateObjCmd( + ClientData clientData, + Tcl_Interp *interp, + int objc, + Tcl_Obj *const *objv) +{ + ReflectedChannel *rcPtr; /* Instance data of the new channel */ + Tcl_Obj *rcId; /* Handle of the new channel */ + int mode; /* R/W mode of new channel. Has to match + * abilities of handler commands */ + Tcl_Obj *cmdObj; /* Command prefix, list of words */ + Tcl_Obj *cmdNameObj; /* Command name */ + Tcl_Channel chan; /* Token for the new channel */ + Tcl_Obj *modeObj; /* mode in obj form for method call */ + int listc; /* Result of 'initialize', and of */ + Tcl_Obj **listv; /* its sublist in the 2nd element */ + int methIndex; /* Encoded method name */ + int result; /* Result code for 'initialize' */ + Tcl_Obj *resObj; /* Result data for 'initialize' */ + int methods; /* Bitmask for supported methods. */ + Channel *chanPtr; /* 'chan' resolved to internal struct. */ + Tcl_Obj *err; /* Error message */ + ReflectedChannelMap *rcmPtr; + /* Map of reflected channels with handlers in + * this interp. */ + Tcl_HashEntry *hPtr; /* Entry in the above map */ + int isNew; /* Placeholder. */ + + /* + * Syntax: chan create MODE CMDPREFIX + * [0] [1] [2] [3] + * + * Actually: rCreate MODE CMDPREFIX + * [0] [1] [2] + */ + +#define MODE (1) +#define CMD (2) + + /* + * Number of arguments... + */ + + if (objc != 3) { + Tcl_WrongNumArgs(interp, 1, objv, "mode cmdprefix"); + return TCL_ERROR; + } + + /* + * First argument is a list of modes. Allowed entries are "read", "write". + * Expect at least one list element. Abbreviations are ok. + */ + + modeObj = objv[MODE]; + if (EncodeEventMask(interp, "mode", objv[MODE], &mode) != TCL_OK) { + return TCL_ERROR; + } + + /* + * Second argument is command prefix, i.e. list of words, first word is + * name of handler command, other words are fixed arguments. Run the + * 'initialize' method to get the list of supported methods. Validate + * this. + */ + + cmdObj = objv[CMD]; + + /* + * Basic check that the command prefix truly is a list. + */ + + if (Tcl_ListObjIndex(interp, cmdObj, 0, &cmdNameObj) != TCL_OK) { + return TCL_ERROR; + } + + /* + * Now create the channel. + */ + + rcId = NextHandle(); + rcPtr = NewReflectedChannel(interp, cmdObj, mode, rcId); + + /* + * Invoke 'initialize' and validate that the handler is present and ok. + * Squash the channel if not. + * + * Note: The conversion of 'mode' back into a Tcl_Obj ensures that + * 'initialize' is invoked with canonical mode names, and no + * abbreviations. Using modeObj directly could feed abbreviations into the + * handler, and the handler is not specified to handle such. + */ + + modeObj = DecodeEventMask(mode); + /* assert modeObj.refCount == 1 */ + result = InvokeTclMethod(rcPtr, METH_INIT, modeObj, NULL, &resObj); + Tcl_DecrRefCount(modeObj); + + if (result != TCL_OK) { + UnmarshallErrorResult(interp, resObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + goto error; + } + + /* + * Verify the result. + * - List, of method names. Convert to mask. + * Check for non-optionals through the mask. + * Compare open mode against optional r/w. + */ + + if (Tcl_ListObjGetElements(NULL, resObj, &listc, &listv) != TCL_OK) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "chan handler \"%s initialize\" returned non-list: %s", + Tcl_GetString(cmdObj), Tcl_GetString(resObj))); + Tcl_DecrRefCount(resObj); + goto error; + } + + methods = 0; + while (listc > 0) { + if (Tcl_GetIndexFromObj(interp, listv[listc-1], methodNames, + "method", TCL_EXACT, &methIndex) != TCL_OK) { + TclNewLiteralStringObj(err, "chan handler \""); + Tcl_AppendObjToObj(err, cmdObj); + Tcl_AppendToObj(err, " initialize\" returned ", -1); + Tcl_AppendObjToObj(err, Tcl_GetObjResult(interp)); + Tcl_SetObjResult(interp, err); + Tcl_DecrRefCount(resObj); + goto error; + } + + methods |= FLAG(methIndex); + listc--; + } + Tcl_DecrRefCount(resObj); + + if ((REQUIRED_METHODS & methods) != REQUIRED_METHODS) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "chan handler \"%s\" does not support all required methods", + Tcl_GetString(cmdObj))); + goto error; + } + + if ((mode & TCL_READABLE) && !HAS(methods, METH_READ)) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "chan handler \"%s\" lacks a \"read\" method", + Tcl_GetString(cmdObj))); + goto error; + } + + if ((mode & TCL_WRITABLE) && !HAS(methods, METH_WRITE)) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "chan handler \"%s\" lacks a \"write\" method", + Tcl_GetString(cmdObj))); + goto error; + } + + if (!IMPLIES(HAS(methods, METH_CGET), HAS(methods, METH_CGETALL))) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "chan handler \"%s\" supports \"cget\" but not \"cgetall\"", + Tcl_GetString(cmdObj))); + goto error; + } + + if (!IMPLIES(HAS(methods, METH_CGETALL), HAS(methods, METH_CGET))) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "chan handler \"%s\" supports \"cgetall\" but not \"cget\"", + Tcl_GetString(cmdObj))); + goto error; + } + + Tcl_ResetResult(interp); + + /* + * Everything is fine now. + */ + + chan = Tcl_CreateChannel(&tclRChannelType, TclGetString(rcId), rcPtr, + mode); + rcPtr->chan = chan; + Tcl_Preserve(chan); + chanPtr = (Channel *) chan; + + if ((methods & NULLABLE_METHODS) != NULLABLE_METHODS) { + /* + * Some of the nullable methods are not supported. We clone the + * channel type, null the associated C functions, and use the result + * as the actual channel type. + */ + + Tcl_ChannelType *clonePtr = ckalloc(sizeof(Tcl_ChannelType)); + + memcpy(clonePtr, &tclRChannelType, sizeof(Tcl_ChannelType)); + + if (!(methods & FLAG(METH_CONFIGURE))) { + clonePtr->setOptionProc = NULL; + } + + if (!(methods & FLAG(METH_CGET)) && !(methods & FLAG(METH_CGETALL))) { + clonePtr->getOptionProc = NULL; + } + if (!(methods & FLAG(METH_BLOCKING))) { + clonePtr->blockModeProc = NULL; + } + if (!(methods & FLAG(METH_SEEK))) { + clonePtr->seekProc = NULL; + clonePtr->wideSeekProc = NULL; + } + + chanPtr->typePtr = clonePtr; + } + + /* + * Register the channel in the I/O system, and in our our map for 'chan + * postevent'. + */ + + Tcl_RegisterChannel(interp, chan); + + rcmPtr = GetReflectedChannelMap(interp); + hPtr = Tcl_CreateHashEntry(&rcmPtr->map, chanPtr->state->channelName, + &isNew); + if (!isNew && chanPtr != Tcl_GetHashValue(hPtr)) { + Tcl_Panic("TclChanCreateObjCmd: duplicate channel names"); + } + Tcl_SetHashValue(hPtr, chan); +#ifdef TCL_THREADS + rcmPtr = GetThreadReflectedChannelMap(); + hPtr = Tcl_CreateHashEntry(&rcmPtr->map, chanPtr->state->channelName, + &isNew); + Tcl_SetHashValue(hPtr, chan); +#endif + + /* + * Return handle as result of command. + */ + + Tcl_SetObjResult(interp, + Tcl_NewStringObj(chanPtr->state->channelName, -1)); + return TCL_OK; + + error: + Tcl_DecrRefCount(rcPtr->name); + Tcl_DecrRefCount(rcPtr->methods); + Tcl_DecrRefCount(rcPtr->cmd); + ckfree((char*) rcPtr); + return TCL_ERROR; + +#undef MODE +#undef CMD +} + +/* + *---------------------------------------------------------------------- + * + * TclChanPostEventObjCmd -- + * + * This function is invoked to process the "chan postevent" Tcl command. + * See the user documentation for details on what it does. + * + * Results: + * A standard Tcl result. + * + * Side effects: + * Posts events to a reflected channel, invokes event handlers. The + * latter implies that arbitrary side effects are possible. + * + *---------------------------------------------------------------------- + */ + +typedef struct ReflectEvent { + Tcl_Event header; + ReflectedChannel *rcPtr; + int events; +} ReflectEvent; + +static int +ReflectEventRun( + Tcl_Event *ev, + int flags) +{ + /* OWNER thread + * + * Note: When the channel is closed any pending events of this type are + * deleted. See ReflectClose() for the Tcl_DeleteEvents() calls + * accomplishing that. + */ + + ReflectEvent *e = (ReflectEvent *) ev; + + Tcl_NotifyChannel(e->rcPtr->chan, e->events); + return 1; +} + +static int +ReflectEventDelete( + Tcl_Event *ev, + ClientData cd) +{ + /* OWNER thread + * + * Invoked by DeleteThreadReflectedChannelMap() and ReflectClose(). The + * latter ensures that no pending events of this type are run on an + * invalid channel. + */ + + ReflectEvent *e = (ReflectEvent *) ev; + + if ((ev->proc != ReflectEventRun) || ((cd != NULL) && (cd != e->rcPtr))) { + return 0; + } + return 1; +} + +int +TclChanPostEventObjCmd( + ClientData clientData, + Tcl_Interp *interp, + int objc, + Tcl_Obj *const *objv) +{ + /* + * Ensure -> HANDLER thread + * + * Syntax: chan postevent CHANNEL EVENTSPEC + * [0] [1] [2] [3] + * + * Actually: rPostevent CHANNEL EVENTSPEC + * [0] [1] [2] + * + * where EVENTSPEC = {read write ...} (Abbreviations allowed as well). + */ + +#define CHAN (1) +#define EVENT (2) + + const char *chanId; /* Tcl level channel handle */ + Tcl_Channel chan; /* Channel associated to the handle */ + const Tcl_ChannelType *chanTypePtr; + /* Its associated driver structure */ + ReflectedChannel *rcPtr; /* Associated instance data */ + int events; /* Mask of events to post */ + ReflectedChannelMap *rcmPtr;/* Map of reflected channels with handlers in + * this interp. */ + Tcl_HashEntry *hPtr; /* Entry in the above map */ + + /* + * Number of arguments... + */ + + if (objc != 3) { + Tcl_WrongNumArgs(interp, 1, objv, "channel eventspec"); + return TCL_ERROR; + } + + /* + * First argument is a channel, a reflected channel, and the call of this + * command is done from the interp defining the channel handler cmd. + */ + + chanId = TclGetString(objv[CHAN]); + + rcmPtr = GetReflectedChannelMap(interp); + hPtr = Tcl_FindHashEntry(&rcmPtr->map, chanId); + + if (hPtr == NULL) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "can not find reflected channel named \"%s\"", chanId)); + Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "CHANNEL", chanId, NULL); + return TCL_ERROR; + } + + /* + * Note that the search above subsumes several of the older checks, namely: + * + * (1) Does the channel handle refer to a reflected channel ? + * (2) Is the post event issued from the interpreter holding the handler + * of the reflected channel ? + * + * A successful search answers yes to both. Because the map holds only + * handles of reflected channels, and only of such whose handler is + * defined in this interpreter. + * + * We keep the old checks for both, for paranioa, but abort now instead of + * throwing errors, as failure now means that our internal datastructures + * have gone seriously haywire. + */ + + chan = Tcl_GetHashValue(hPtr); + chanTypePtr = Tcl_GetChannelType(chan); + + /* + * We use a function referenced by the channel type as our cookie to + * detect calls to non-reflecting channels. The channel type itself is not + * suitable, as it might not be the static definition in this file, but a + * clone thereof. And while we have reserved the name of the type nothing + * in the core checks against violation, so someone else might have + * created a channel type using our name, clashing with ourselves. + */ + + if (chanTypePtr->watchProc != &ReflectWatch) { + Tcl_Panic("TclChanPostEventObjCmd: channel is not a reflected channel"); + } + + rcPtr = Tcl_GetChannelInstanceData(chan); + + if (rcPtr->interp != interp) { + Tcl_Panic("TclChanPostEventObjCmd: postevent accepted for call from outside interpreter"); + } + + /* + * Second argument is a list of events. Allowed entries are "read", + * "write". Expect at least one list element. Abbreviations are ok. + */ + + if (EncodeEventMask(interp, "event", objv[EVENT], &events) != TCL_OK) { + return TCL_ERROR; + } + + /* + * Check that the channel is actually interested in the provided events. + */ + + if (events & ~rcPtr->interest) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "tried to post events channel \"%s\" is not interested in", + chanId)); + return TCL_ERROR; + } + + /* + * We have the channel and the events to post. + */ + +#ifdef TCL_THREADS + if (rcPtr->owner == rcPtr->thread) { +#endif + Tcl_NotifyChannel(chan, events); +#ifdef TCL_THREADS + } else { + ReflectEvent *ev = ckalloc(sizeof(ReflectEvent)); + + ev->header.proc = ReflectEventRun; + ev->events = events; + ev->rcPtr = rcPtr; + + /* + * We are not preserving the structure here. When the channel is + * closed any pending events are deleted, see ReflectClose(), and + * ReflectEventDelete(). Trying to preserve and later release when the + * event is run may generate a situation where the channel structure + * is deleted but not our structure, crashing in + * FreeReflectedChannel(). + * + * Force creation of the RCM, for proper cleanup on thread teardown. + * The teardown of unprocessed events is currently coupled to the + * thread reflected channel map + */ + + (void) GetThreadReflectedChannelMap(); + + /* XXX Race condition !! + * XXX The destination thread may not exist anymore already. + * XXX (Delayed postevent executed after channel got removed). + * XXX Can we detect this ? (check the validity of the owner threadid ?) + * XXX Actually, in that case the channel should be dead also ! + */ + + Tcl_ThreadQueueEvent(rcPtr->owner, (Tcl_Event *) ev, TCL_QUEUE_TAIL); + Tcl_ThreadAlert(rcPtr->owner); + } +#endif + + /* + * Squash interp results left by the event script. + */ + + Tcl_ResetResult(interp); + return TCL_OK; + +#undef CHAN +#undef EVENT +} + +/* + * Channel error message marshalling utilities. + */ + +static Tcl_Obj * +MarshallError( + Tcl_Interp *interp) +{ + /* + * Capture the result status of the interpreter into a string. => List of + * options and values, followed by the error message. The result has + * refCount 0. + */ + + Tcl_Obj *returnOpt = Tcl_GetReturnOptions(interp, TCL_ERROR); + + /* + * => returnOpt.refCount == 0. We can append directly. + */ + + Tcl_ListObjAppendElement(NULL, returnOpt, Tcl_GetObjResult(interp)); + return returnOpt; +} + +static void +UnmarshallErrorResult( + Tcl_Interp *interp, + Tcl_Obj *msgObj) +{ + int lc; + Tcl_Obj **lv; + int explicitResult; + int numOptions; + + /* + * Process the caught message. + * + * Syntax = (option value)... ?message? + * + * Bad syntax causes a panic. This is OK because the other side uses + * Tcl_GetReturnOptions and list construction functions to marshall the + * information; if we panic here, something has gone badly wrong already. + */ + + if (Tcl_ListObjGetElements(interp, msgObj, &lc, &lv) != TCL_OK) { + Tcl_Panic("TclChanCaughtErrorBypass: Bad syntax of caught result"); + } + if (interp == NULL) { + return; + } + + explicitResult = lc & 1; /* Odd number of values? */ + numOptions = lc - explicitResult; + + if (explicitResult) { + Tcl_SetObjResult(interp, lv[lc-1]); + } + + (void) Tcl_SetReturnOptions(interp, Tcl_NewListObj(numOptions, lv)); + ((Interp *) interp)->flags &= ~ERR_ALREADY_LOGGED; +} + +int +TclChanCaughtErrorBypass( + Tcl_Interp *interp, + Tcl_Channel chan) +{ + Tcl_Obj *chanMsgObj = NULL; + Tcl_Obj *interpMsgObj = NULL; + Tcl_Obj *msgObj = NULL; + + /* + * Get a bypassed error message from channel and/or interpreter, save the + * reference, then kill the returned objects, if there were any. If there + * are messages in both the channel has preference. + */ + + if ((chan == NULL) && (interp == NULL)) { + return 0; + } + + if (chan != NULL) { + Tcl_GetChannelError(chan, &chanMsgObj); + } + if (interp != NULL) { + Tcl_GetChannelErrorInterp(interp, &interpMsgObj); + } + + if (chanMsgObj != NULL) { + msgObj = chanMsgObj; + } else if (interpMsgObj != NULL) { + msgObj = interpMsgObj; + } + if (msgObj != NULL) { + Tcl_IncrRefCount(msgObj); + } + + if (chanMsgObj != NULL) { + Tcl_DecrRefCount(chanMsgObj); + } + if (interpMsgObj != NULL) { + Tcl_DecrRefCount(interpMsgObj); + } + + /* + * No message returned, nothing caught. + */ + + if (msgObj == NULL) { + return 0; + } + + UnmarshallErrorResult(interp, msgObj); + + Tcl_DecrRefCount(msgObj); + return 1; +} + +/* + * Driver functions. ================================================ + */ + +/* + *---------------------------------------------------------------------- + * + * ReflectClose -- + * + * This function is invoked when the channel is closed, to delete the + * driver specific instance data. + * + * Results: + * A posix error. + * + * Side effects: + * Releases memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectClose( + ClientData clientData, + Tcl_Interp *interp) +{ + ReflectedChannel *rcPtr = clientData; + int result; /* Result code for 'close' */ + Tcl_Obj *resObj; /* Result data for 'close' */ + ReflectedChannelMap *rcmPtr;/* Map of reflected channels with handlers in + * this interp */ + Tcl_HashEntry *hPtr; /* Entry in the above map */ + + if (TclInThreadExit()) { + /* + * This call comes from TclFinalizeIOSystem. There are no + * interpreters, and therefore we cannot call upon the handler command + * anymore. Threading is irrelevant as well. We simply clean up all + * our C level data structures and leave the Tcl level to the other + * finalization functions. + */ + + /* + * THREADED => Forward this to the origin thread + * + * Note: DeleteThreadReflectedChannelMap() is the thread exit handler + * for the origin thread. Use this to clean up the structure? Except + * if lost? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + ForwardOpToHandlerThread(rcPtr, ForwardedClose, &p); + result = p.base.code; + + /* + * Now squash the pending reflection events for this channel. + */ + + Tcl_DeleteEvents(ReflectEventDelete, rcPtr); + + if (result != TCL_OK) { + FreeReceivedError(&p); + } + return EOK; + } +#endif + + Tcl_EventuallyFree(rcPtr, (Tcl_FreeProc *) FreeReflectedChannel); + return EOK; + } + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + ForwardOpToHandlerThread(rcPtr, ForwardedClose, &p); + result = p.base.code; + + /* + * Now squash the pending reflection events for this channel. + */ + + Tcl_DeleteEvents(ReflectEventDelete, rcPtr); + + if (result != TCL_OK) { + PassReceivedErrorInterp(interp, &p); + } + } else { +#endif + result = InvokeTclMethod(rcPtr, METH_FINAL, NULL, NULL, &resObj); + if ((result != TCL_OK) && (interp != NULL)) { + Tcl_SetChannelErrorInterp(interp, resObj); + } + + Tcl_DecrRefCount(resObj); /* Remove reference we held from the + * invoke */ + + /* + * Remove the channel from the map before releasing the memory, to + * prevent future accesses (like by 'postevent') from finding and + * dereferencing a dangling pointer. + * + * NOTE: The channel may not be in the map. This is ok, that happens + * when the channel was created in a different interpreter and/or + * thread and then was moved here. + * + * NOTE: The channel may have been removed from the map already via + * the per-interp DeleteReflectedChannelMap exit-handler. + */ + + if (!rcPtr->dead) { + rcmPtr = GetReflectedChannelMap(rcPtr->interp); + hPtr = Tcl_FindHashEntry(&rcmPtr->map, + Tcl_GetChannelName(rcPtr->chan)); + if (hPtr) { + Tcl_DeleteHashEntry(hPtr); + } + } +#ifdef TCL_THREADS + rcmPtr = GetThreadReflectedChannelMap(); + hPtr = Tcl_FindHashEntry(&rcmPtr->map, + Tcl_GetChannelName(rcPtr->chan)); + if (hPtr) { + Tcl_DeleteHashEntry(hPtr); + } +#endif + + Tcl_EventuallyFree(rcPtr, (Tcl_FreeProc *) FreeReflectedChannel); +#ifdef TCL_THREADS + } +#endif + return (result == TCL_OK) ? EOK : EINVAL; +} + +/* + *---------------------------------------------------------------------- + * + * ReflectInput -- + * + * This function is invoked when more data is requested from the channel. + * + * Results: + * The number of bytes read. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectInput( + ClientData clientData, + char *buf, + int toRead, + int *errorCodePtr) +{ + ReflectedChannel *rcPtr = clientData; + Tcl_Obj *toReadObj; + int bytec; /* Number of returned bytes */ + unsigned char *bytev; /* Array of returned bytes */ + Tcl_Obj *resObj; /* Result data for 'read' */ + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + p.input.buf = buf; + p.input.toRead = toRead; + + ForwardOpToHandlerThread(rcPtr, ForwardedInput, &p); + + if (p.base.code != TCL_OK) { + if (p.base.code < 0) { + /* No error message, this is an errno signal. */ + *errorCodePtr = -p.base.code; + } else { + PassReceivedError(rcPtr->chan, &p); + *errorCodePtr = EINVAL; + } + p.input.toRead = -1; + } else { + *errorCodePtr = EOK; + } + + return p.input.toRead; + } +#endif + + /* ASSERT: rcPtr->method & FLAG(METH_READ) */ + /* ASSERT: rcPtr->mode & TCL_READABLE */ + + Tcl_Preserve(rcPtr); + + toReadObj = Tcl_NewIntObj(toRead); + Tcl_IncrRefCount(toReadObj); + + if (InvokeTclMethod(rcPtr, METH_READ, toReadObj, NULL, &resObj)!=TCL_OK) { + int code = ErrnoReturn(rcPtr, resObj); + + if (code < 0) { + *errorCodePtr = -code; + goto error; + } + + Tcl_SetChannelError(rcPtr->chan, resObj); + goto invalid; + } + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + + if (toRead < bytec) { + SetChannelErrorStr(rcPtr->chan, msg_read_toomuch); + goto invalid; + } + + *errorCodePtr = EOK; + + if (bytec > 0) { + memcpy(buf, bytev, (size_t) bytec); + } + + stop: + Tcl_DecrRefCount(toReadObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + Tcl_Release(rcPtr); + return bytec; + invalid: + *errorCodePtr = EINVAL; + error: + bytec = -1; + goto stop; +} + +/* + *---------------------------------------------------------------------- + * + * ReflectOutput -- + * + * This function is invoked when data is writen to the channel. + * + * Results: + * The number of bytes actually written. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectOutput( + ClientData clientData, + const char *buf, + int toWrite, + int *errorCodePtr) +{ + ReflectedChannel *rcPtr = clientData; + Tcl_Obj *bufObj; + Tcl_Obj *resObj; /* Result data for 'write' */ + int written; + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + p.output.buf = buf; + p.output.toWrite = toWrite; + + ForwardOpToHandlerThread(rcPtr, ForwardedOutput, &p); + + if (p.base.code != TCL_OK) { + if (p.base.code < 0) { + /* No error message, this is an errno signal. */ + *errorCodePtr = -p.base.code; + } else { + PassReceivedError(rcPtr->chan, &p); + *errorCodePtr = EINVAL; + } + p.output.toWrite = -1; + } else { + *errorCodePtr = EOK; + } + + return p.output.toWrite; + } +#endif + + /* ASSERT: rcPtr->method & FLAG(METH_WRITE) */ + /* ASSERT: rcPtr->mode & TCL_WRITABLE */ + + Tcl_Preserve(rcPtr); + + bufObj = Tcl_NewByteArrayObj((unsigned char *) buf, toWrite); + Tcl_IncrRefCount(bufObj); + + if (InvokeTclMethod(rcPtr, METH_WRITE, bufObj, NULL, &resObj) != TCL_OK) { + int code = ErrnoReturn(rcPtr, resObj); + + if (code < 0) { + *errorCodePtr = -code; + goto error; + } + + Tcl_SetChannelError(rcPtr->chan, resObj); + goto invalid; + } + + if (Tcl_GetIntFromObj(rcPtr->interp, resObj, &written) != TCL_OK) { + Tcl_SetChannelError(rcPtr->chan, MarshallError(rcPtr->interp)); + goto invalid; + } + + if ((written == 0) && (toWrite > 0)) { + /* + * The handler claims to have written nothing of what it was + * given. That is bad. + */ + + SetChannelErrorStr(rcPtr->chan, msg_write_nothing); + goto invalid; + } + if (toWrite < written) { + /* + * The handler claims to have written more than it was given. That is + * bad. Note that the I/O core would crash if we were to return this + * information, trying to write -nnn bytes in the next iteration. + */ + + SetChannelErrorStr(rcPtr->chan, msg_write_toomuch); + goto invalid; + } + + *errorCodePtr = EOK; + stop: + Tcl_DecrRefCount(bufObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + Tcl_Release(rcPtr); + return written; + invalid: + *errorCodePtr = EINVAL; + error: + written = -1; + goto stop; +} + +/* + *---------------------------------------------------------------------- + * + * ReflectSeekWide / ReflectSeek -- + * + * This function is invoked when the user wishes to seek on the channel. + * + * Results: + * The new location of the access point. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static Tcl_WideInt +ReflectSeekWide( + ClientData clientData, + Tcl_WideInt offset, + int seekMode, + int *errorCodePtr) +{ + ReflectedChannel *rcPtr = clientData; + Tcl_Obj *offObj, *baseObj; + Tcl_Obj *resObj; /* Result for 'seek' */ + Tcl_WideInt newLoc; + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + p.seek.seekMode = seekMode; + p.seek.offset = offset; + + ForwardOpToHandlerThread(rcPtr, ForwardedSeek, &p); + + if (p.base.code != TCL_OK) { + PassReceivedError(rcPtr->chan, &p); + *errorCodePtr = EINVAL; + p.seek.offset = -1; + } else { + *errorCodePtr = EOK; + } + + return p.seek.offset; + } +#endif + + /* ASSERT: rcPtr->method & FLAG(METH_SEEK) */ + + Tcl_Preserve(rcPtr); + + offObj = Tcl_NewWideIntObj(offset); + baseObj = Tcl_NewStringObj( + (seekMode == SEEK_SET) ? "start" : + (seekMode == SEEK_CUR) ? "current" : "end", -1); + Tcl_IncrRefCount(offObj); + Tcl_IncrRefCount(baseObj); + + if (InvokeTclMethod(rcPtr, METH_SEEK, offObj, baseObj, &resObj)!=TCL_OK) { + Tcl_SetChannelError(rcPtr->chan, resObj); + goto invalid; + } + + if (Tcl_GetWideIntFromObj(rcPtr->interp, resObj, &newLoc) != TCL_OK) { + Tcl_SetChannelError(rcPtr->chan, MarshallError(rcPtr->interp)); + goto invalid; + } + + if (newLoc < Tcl_LongAsWide(0)) { + SetChannelErrorStr(rcPtr->chan, msg_seek_beforestart); + goto invalid; + } + + *errorCodePtr = EOK; + stop: + Tcl_DecrRefCount(offObj); + Tcl_DecrRefCount(baseObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + Tcl_Release(rcPtr); + return newLoc; + invalid: + *errorCodePtr = EINVAL; + newLoc = -1; + goto stop; +} + +static int +ReflectSeek( + ClientData clientData, + long offset, + int seekMode, + int *errorCodePtr) +{ + /* + * This function can be invoked from a transformation which is based on + * standard seeking, i.e. non-wide. Because of this we have to implement + * it, a dummy is not enough. We simply delegate the call to the wide + * routine. + */ + + return (int) ReflectSeekWide(clientData, Tcl_LongAsWide(offset), seekMode, + errorCodePtr); +} + +/* + *---------------------------------------------------------------------- + * + * ReflectWatch -- + * + * This function is invoked to tell the channel what events the I/O + * system is interested in. + * + * Results: + * None. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static void +ReflectWatch( + ClientData clientData, + int mask) +{ + ReflectedChannel *rcPtr = clientData; + Tcl_Obj *maskObj; + + /* + * We restrict the interest to what the channel can support. IOW there + * will never be write events for a channel which is not writable. + * Analoguously for read events and non-readable channels. + */ + + mask &= rcPtr->mode; + + if (mask == rcPtr->interest) { + /* + * Same old, same old, why should we do something? + */ + + return; + } + + rcPtr->interest = mask; + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + p.watch.mask = mask; + ForwardOpToHandlerThread(rcPtr, ForwardedWatch, &p); + + /* + * Any failure from the forward is ignored. We have no place to put + * this. + */ + + return; + } +#endif + + Tcl_Preserve(rcPtr); + + maskObj = DecodeEventMask(mask); + /* assert maskObj.refCount == 1 */ + (void) InvokeTclMethod(rcPtr, METH_WATCH, maskObj, NULL, NULL); + Tcl_DecrRefCount(maskObj); + + Tcl_Release(rcPtr); +} + +/* + *---------------------------------------------------------------------- + * + * ReflectBlock -- + * + * This function is invoked to tell the channel which blocking behaviour + * is required of it. + * + * Results: + * A posix error number. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectBlock( + ClientData clientData, + int nonblocking) +{ + ReflectedChannel *rcPtr = clientData; + Tcl_Obj *blockObj; + int errorNum; /* EINVAL or EOK (success). */ + Tcl_Obj *resObj; /* Result data for 'blocking' */ + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + p.block.nonblocking = nonblocking; + + ForwardOpToHandlerThread(rcPtr, ForwardedBlock, &p); + + if (p.base.code != TCL_OK) { + PassReceivedError(rcPtr->chan, &p); + return EINVAL; + } + + return EOK; + } +#endif + + blockObj = Tcl_NewBooleanObj(!nonblocking); + Tcl_IncrRefCount(blockObj); + + Tcl_Preserve(rcPtr); + + if (InvokeTclMethod(rcPtr,METH_BLOCKING,blockObj,NULL,&resObj)!=TCL_OK) { + Tcl_SetChannelError(rcPtr->chan, resObj); + errorNum = EINVAL; + } else { + errorNum = EOK; + } + + Tcl_DecrRefCount(blockObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + + Tcl_Release(rcPtr); + return errorNum; +} + +#ifdef TCL_THREADS +/* + *---------------------------------------------------------------------- + * + * ReflectThread -- + * + * This function is invoked to tell the channel about thread movements. + * + * Results: + * None. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static void +ReflectThread( + ClientData clientData, + int action) +{ + ReflectedChannel *rcPtr = clientData; + + switch (action) { + case TCL_CHANNEL_THREAD_INSERT: + rcPtr->owner = Tcl_GetCurrentThread(); + break; + case TCL_CHANNEL_THREAD_REMOVE: + rcPtr->owner = NULL; + break; + default: + Tcl_Panic("Unknown thread action code."); + break; + } +} + +#endif +/* + *---------------------------------------------------------------------- + * + * ReflectSetOption -- + * + * This function is invoked to configure a channel option. + * + * Results: + * A standard Tcl result code. + * + * Side effects: + * Arbitrary, as it calls upon a Tcl script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectSetOption( + ClientData clientData, /* Channel to query */ + Tcl_Interp *interp, /* Interpreter to leave error messages in */ + const char *optionName, /* Name of requested option */ + const char *newValue) /* The new value */ +{ + ReflectedChannel *rcPtr = clientData; + Tcl_Obj *optionObj, *valueObj; + int result; /* Result code for 'configure' */ + Tcl_Obj *resObj; /* Result data for 'configure' */ + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + p.setOpt.name = optionName; + p.setOpt.value = newValue; + + ForwardOpToHandlerThread(rcPtr, ForwardedSetOpt, &p); + + if (p.base.code != TCL_OK) { + Tcl_Obj *err = Tcl_NewStringObj(p.base.msgStr, -1); + + UnmarshallErrorResult(interp, err); + Tcl_DecrRefCount(err); + FreeReceivedError(&p); + } + + return p.base.code; + } +#endif + Tcl_Preserve(rcPtr); + + optionObj = Tcl_NewStringObj(optionName, -1); + valueObj = Tcl_NewStringObj(newValue, -1); + + Tcl_IncrRefCount(optionObj); + Tcl_IncrRefCount(valueObj); + + result = InvokeTclMethod(rcPtr, METH_CONFIGURE,optionObj,valueObj, &resObj); + if (result != TCL_OK) { + UnmarshallErrorResult(interp, resObj); + } + + Tcl_DecrRefCount(optionObj); + Tcl_DecrRefCount(valueObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + Tcl_Release(rcPtr); + return result; +} + +/* + *---------------------------------------------------------------------- + * + * ReflectGetOption -- + * + * This function is invoked to retrieve all or a channel option. + * + * Results: + * A standard Tcl result code. + * + * Side effects: + * Arbitrary, as it calls upon a Tcl script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectGetOption( + ClientData clientData, /* Channel to query */ + Tcl_Interp *interp, /* Interpreter to leave error messages in */ + const char *optionName, /* Name of reuqested option */ + Tcl_DString *dsPtr) /* String to place the result into */ +{ + /* + * This code is special. It has regular passing of Tcl result, and errors. + * The bypass functions are not required. + */ + + ReflectedChannel *rcPtr = clientData; + Tcl_Obj *optionObj; + Tcl_Obj *resObj; /* Result data for 'configure' */ + int listc, result = TCL_OK; + Tcl_Obj **listv; + MethodName method; + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rcPtr->thread != Tcl_GetCurrentThread()) { + int opcode; + ForwardParam p; + + p.getOpt.name = optionName; + p.getOpt.value = dsPtr; + + if (optionName == NULL) { + opcode = ForwardedGetOptAll; + } else { + opcode = ForwardedGetOpt; + } + + ForwardOpToHandlerThread(rcPtr, opcode, &p); + + if (p.base.code != TCL_OK) { + Tcl_Obj *err = Tcl_NewStringObj(p.base.msgStr, -1); + + UnmarshallErrorResult(interp, err); + Tcl_DecrRefCount(err); + FreeReceivedError(&p); + } + + return p.base.code; + } +#endif + + if (optionName == NULL) { + /* + * Retrieve all options. + */ + + method = METH_CGETALL; + optionObj = NULL; + } else { + /* + * Retrieve the value of one option. + */ + + method = METH_CGET; + optionObj = Tcl_NewStringObj(optionName, -1); + Tcl_IncrRefCount(optionObj); + } + + Tcl_Preserve(rcPtr); + + if (InvokeTclMethod(rcPtr, method, optionObj, NULL, &resObj)!=TCL_OK) { + UnmarshallErrorResult(interp, resObj); + goto error; + } + + /* + * The result has to go into the 'dsPtr' for propagation to the caller of + * the driver. + */ + + if (optionObj != NULL) { + TclDStringAppendObj(dsPtr, resObj); + goto ok; + } + + /* + * Extract the list and append each item as element. + */ + + /* + * NOTE (4): If we extract the string rep we can assume a properly quoted + * string. Together with a separating space this way of simply appending + * the whole string rep might be faster. It also doesn't check if the + * result is a valid list. Nor that the list has an even number elements. + */ + + if (Tcl_ListObjGetElements(interp, resObj, &listc, &listv) != TCL_OK) { + goto error; + } + + if ((listc % 2) == 1) { + /* + * Odd number of elements is wrong. + */ + + Tcl_ResetResult(interp); + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "Expected list with even number of " + "elements, got %d element%s instead", listc, + (listc == 1 ? "" : "s"))); + goto error; + } else { + int len; + const char *str = Tcl_GetStringFromObj(resObj, &len); + + if (len) { + TclDStringAppendLiteral(dsPtr, " "); + Tcl_DStringAppend(dsPtr, str, len); + } + goto ok; + } + + ok: + result = TCL_OK; + stop: + if (optionObj) { + Tcl_DecrRefCount(optionObj); + } + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + Tcl_Release(rcPtr); + return result; + error: + result = TCL_ERROR; + goto stop; +} + +/* + * Helpers. ========================================================= + */ + +/* + *---------------------------------------------------------------------- + * + * EncodeEventMask -- + * + * This function takes a list of event items and constructs the + * equivalent internal bitmask. The list must contain at least one + * element. Elements are "read", "write", or any unique abbreviation of + * them. Note that the bitmask is not changed if problems are + * encountered. + * + * Results: + * A standard Tcl error code. A bitmask where TCL_READABLE and/or + * TCL_WRITABLE can be set. + * + * Side effects: + * May shimmer 'obj' to a list representation. May place an error message + * into the interp result. + * + *---------------------------------------------------------------------- + */ + +static int +EncodeEventMask( + Tcl_Interp *interp, + const char *objName, + Tcl_Obj *obj, + int *mask) +{ + int events; /* Mask of events to post */ + int listc; /* #elements in eventspec list */ + Tcl_Obj **listv; /* Elements of eventspec list */ + int evIndex; /* Id of event for an element of the eventspec + * list. */ + + if (Tcl_ListObjGetElements(interp, obj, &listc, &listv) != TCL_OK) { + return TCL_ERROR; + } + + if (listc < 1) { + Tcl_SetObjResult(interp, Tcl_ObjPrintf( + "bad %s list: is empty", objName)); + return TCL_ERROR; + } + + events = 0; + while (listc > 0) { + if (Tcl_GetIndexFromObj(interp, listv[listc-1], eventOptions, + objName, 0, &evIndex) != TCL_OK) { + return TCL_ERROR; + } + switch (evIndex) { + case EVENT_READ: + events |= TCL_READABLE; + break; + case EVENT_WRITE: + events |= TCL_WRITABLE; + break; + } + listc --; + } + + *mask = events; + return TCL_OK; +} + +/* + *---------------------------------------------------------------------- + * + * DecodeEventMask -- + * + * This function takes an internal bitmask of events and constructs the + * equivalent list of event items. + * + * Results, Contract: + * A Tcl_Obj reference. The object will have a refCount of one. The user + * has to decrement it to release the object. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static Tcl_Obj * +DecodeEventMask( + int mask) +{ + register const char *eventStr; + Tcl_Obj *evObj; + + switch (mask & RANDW) { + case RANDW: + eventStr = "read write"; + break; + case TCL_READABLE: + eventStr = "read"; + break; + case TCL_WRITABLE: + eventStr = "write"; + break; + default: + eventStr = ""; + break; + } + + evObj = Tcl_NewStringObj(eventStr, -1); + Tcl_IncrRefCount(evObj); + /* assert evObj.refCount == 1 */ + return evObj; +} + +/* + *---------------------------------------------------------------------- + * + * NewReflectedChannel -- + * + * This function is invoked to allocate and initialize the instance data + * of a new reflected channel. + * + * Results: + * A heap-allocated channel instance. + * + * Side effects: + * Allocates memory. + * + *---------------------------------------------------------------------- + */ + +static ReflectedChannel * +NewReflectedChannel( + Tcl_Interp *interp, + Tcl_Obj *cmdpfxObj, + int mode, + Tcl_Obj *handleObj) +{ + ReflectedChannel *rcPtr; + MethodName mn = METH_BLOCKING; + + rcPtr = ckalloc(sizeof(ReflectedChannel)); + + /* rcPtr->chan: Assigned by caller. Dummy data here. */ + + rcPtr->chan = NULL; + rcPtr->interp = interp; + rcPtr->dead = 0; +#ifdef TCL_THREADS + rcPtr->thread = Tcl_GetCurrentThread(); +#endif + rcPtr->mode = mode; + rcPtr->interest = 0; /* Initially no interest registered */ + + /* ASSERT: cmdpfxObj is a Tcl List */ + rcPtr->cmd = TclListObjCopy(NULL, cmdpfxObj); + Tcl_IncrRefCount(rcPtr->cmd); + rcPtr->methods = Tcl_NewListObj(METH_WRITE + 1, NULL); + while (mn <= METH_WRITE) { + Tcl_ListObjAppendElement(NULL, rcPtr->methods, + Tcl_NewStringObj(methodNames[mn++], -1)); + } + Tcl_IncrRefCount(rcPtr->methods); + rcPtr->name = handleObj; + Tcl_IncrRefCount(rcPtr->name); + return rcPtr; +} + +/* + *---------------------------------------------------------------------- + * + * NextHandle -- + * + * This function is invoked to generate a channel handle for a new + * reflected channel. + * + * Results: + * A Tcl_Obj containing the string of the new channel handle. The + * refcount of the returned object is -- zero --. + * + * Side effects: + * May allocate memory. Mutex protected critical section locks out other + * threads for a short time. + * + *---------------------------------------------------------------------- + */ + +static Tcl_Obj * +NextHandle(void) +{ + /* + * Count number of generated reflected channels. Used for id generation. + * Ids are never reclaimed and there is no dealing with wrap around. On + * the other hand, "unsigned long" should be big enough except for + * absolute longrunners (generate a 100 ids per second => overflow will + * occur in 1 1/3 years). + */ + + TCL_DECLARE_MUTEX(rcCounterMutex) + static unsigned long rcCounter = 0; + Tcl_Obj *resObj; + + Tcl_MutexLock(&rcCounterMutex); + resObj = Tcl_ObjPrintf("rc%lu", rcCounter); + rcCounter++; + Tcl_MutexUnlock(&rcCounterMutex); + + return resObj; +} + +static void +FreeReflectedChannel( + ReflectedChannel *rcPtr) +{ + Channel *chanPtr = (Channel *) rcPtr->chan; + + if (chanPtr->typePtr != &tclRChannelType) { + /* + * Delete a cloned ChannelType structure. + */ + + ckfree(chanPtr->typePtr); + chanPtr->typePtr = NULL; + } + Tcl_Release(chanPtr); + Tcl_DecrRefCount(rcPtr->name); + Tcl_DecrRefCount(rcPtr->methods); + Tcl_DecrRefCount(rcPtr->cmd); + ckfree(rcPtr); +} + +/* + *---------------------------------------------------------------------- + * + * InvokeTclMethod -- + * + * This function is used to invoke the Tcl level of a reflected channel. + * It handles all the command assembly, invokation, and generic state and + * result mgmt. It does *not* handle thread redirection; that is the + * responsibility of clients of this function. + * + * Results: + * Result code and data as returned by the method. + * + * Side effects: + * Arbitrary, as it calls upon a Tcl script. + * + * Contract: + * argOneObj.refCount >= 1 on entry and exit, if argOneObj != NULL + * argTwoObj.refCount >= 1 on entry and exit, if argTwoObj != NULL + * resObj.refCount in {0, 1, ...} + * + *---------------------------------------------------------------------- + */ + +static int +InvokeTclMethod( + ReflectedChannel *rcPtr, + MethodName method, + Tcl_Obj *argOneObj, /* NULL'able */ + Tcl_Obj *argTwoObj, /* NULL'able */ + Tcl_Obj **resultObjPtr) /* NULL'able */ +{ + Tcl_Obj *methObj = NULL; /* Method name in object form */ + Tcl_InterpState sr; /* State of handler interp */ + int result; /* Result code of method invokation */ + Tcl_Obj *resObj = NULL; /* Result of method invokation. */ + Tcl_Obj *cmd; + + if (rcPtr->dead) { + /* + * The channel is marked as dead. Bail out immediately, with an + * appropriate error. + */ + + if (resultObjPtr != NULL) { + resObj = Tcl_NewStringObj(msg_dstlost,-1); + *resultObjPtr = resObj; + Tcl_IncrRefCount(resObj); + } + + /* + * Not touching argOneObj, argTwoObj, they have not been used. + * See the contract as well. + */ + + return TCL_ERROR; + } + + /* + * Insert method into the callback command, after the command prefix, + * before the channel id. + */ + + cmd = TclListObjCopy(NULL, rcPtr->cmd); + + Tcl_ListObjIndex(NULL, rcPtr->methods, method, &methObj); + Tcl_ListObjAppendElement(NULL, cmd, methObj); + Tcl_ListObjAppendElement(NULL, cmd, rcPtr->name); + + /* + * Append the additional argument containing method specific details + * behind the channel id. If specified. + * + * Because of the contract there is no need to increment the refcounts. + * The objects will survive the Tcl_EvalObjv without change. + */ + + if (argOneObj) { + Tcl_ListObjAppendElement(NULL, cmd, argOneObj); + if (argTwoObj) { + Tcl_ListObjAppendElement(NULL, cmd, argTwoObj); + } + } + + /* + * And run the handler... This is done in auch a manner which leaves any + * existing state intact. + */ + + Tcl_IncrRefCount(cmd); + sr = Tcl_SaveInterpState(rcPtr->interp, 0 /* Dummy */); + Tcl_Preserve(rcPtr->interp); + result = Tcl_EvalObjEx(rcPtr->interp, cmd, TCL_EVAL_GLOBAL); + + /* + * We do not try to extract the result information if the caller has no + * interest in it. I.e. there is no need to put effort into creating + * something which is discarded immediately after. + */ + + if (resultObjPtr) { + if (result == TCL_OK) { + /* + * Ok result taken as is, also if the caller requests that there + * is no capture. + */ + + resObj = Tcl_GetObjResult(rcPtr->interp); + } else { + /* + * Non-ok result is always treated as an error. We have to capture + * the full state of the result, including additional options. + * + * This is complex and ugly, and would be completely unnecessary + * if we only added support for a TCL_FORBID_EXCEPTIONS flag. + */ + + if (result != TCL_ERROR) { + int cmdLen; + const char *cmdString = Tcl_GetStringFromObj(cmd, &cmdLen); + + Tcl_IncrRefCount(cmd); + Tcl_ResetResult(rcPtr->interp); + Tcl_SetObjResult(rcPtr->interp, Tcl_ObjPrintf( + "chan handler returned bad code: %d", result)); + Tcl_LogCommandInfo(rcPtr->interp, cmdString, cmdString, + cmdLen); + Tcl_DecrRefCount(cmd); + result = TCL_ERROR; + } + Tcl_AppendObjToErrorInfo(rcPtr->interp, Tcl_ObjPrintf( + "\n (chan handler subcommand \"%s\")", + methodNames[method])); + resObj = MarshallError(rcPtr->interp); + } + Tcl_IncrRefCount(resObj); + } + Tcl_DecrRefCount(cmd); + Tcl_RestoreInterpState(rcPtr->interp, sr); + Tcl_Release(rcPtr->interp); + + /* + * The resObj has a ref count of 1 at this location. This means that the + * caller of InvokeTclMethod has to dispose of it (but only if it was + * returned to it). + */ + + if (resultObjPtr != NULL) { + *resultObjPtr = resObj; + } + + /* + * There no need to handle the case where nothing is returned, because for + * that case resObj was not set anyway. + */ + + return result; +} + +/* + *---------------------------------------------------------------------- + * + * ErrnoReturn -- + * + * Checks a method error result if it returned an 'errno'. + * + * Results: + * The negative errno found in the error result, or 0. + * + * Side effects: + * None. + * + * Users: + * ReflectInput/Output(), to enable the signaling of EAGAIN + * on 0-sized short reads/writes. + * + *---------------------------------------------------------------------- + */ + +static int +ErrnoReturn( + ReflectedChannel *rcPtr, + Tcl_Obj *resObj) +{ + int code; + Tcl_InterpState sr; /* State of handler interp */ + + if (rcPtr->dead) { + return 0; + } + + sr = Tcl_SaveInterpState(rcPtr->interp, 0 /* Dummy */); + UnmarshallErrorResult(rcPtr->interp, resObj); + + resObj = Tcl_GetObjResult(rcPtr->interp); + + if (((Tcl_GetIntFromObj(rcPtr->interp, resObj, &code) != TCL_OK) + || (code >= 0))) { + if (strcmp("EAGAIN", Tcl_GetString(resObj)) == 0) { + code = -EAGAIN; + } else { + code = 0; + } + } + + Tcl_RestoreInterpState(rcPtr->interp, sr); + return code; +} + +/* + *---------------------------------------------------------------------- + * + * GetReflectedChannelMap -- + * + * Gets and potentially initializes the reflected channel map for an + * interpreter. + * + * Results: + * A pointer to the map created, for use by the caller. + * + * Side effects: + * Initializes the reflected channel map for an interpreter. + * + *---------------------------------------------------------------------- + */ + +static ReflectedChannelMap * +GetReflectedChannelMap( + Tcl_Interp *interp) +{ + ReflectedChannelMap *rcmPtr = Tcl_GetAssocData(interp, RCMKEY, NULL); + + if (rcmPtr == NULL) { + rcmPtr = ckalloc(sizeof(ReflectedChannelMap)); + Tcl_InitHashTable(&rcmPtr->map, TCL_STRING_KEYS); + Tcl_SetAssocData(interp, RCMKEY, + (Tcl_InterpDeleteProc *) DeleteReflectedChannelMap, rcmPtr); + } + return rcmPtr; +} + +/* + *---------------------------------------------------------------------- + * + * DeleteReflectedChannelMap -- + * + * Deletes the channel table for an interpreter, closing any open + * channels whose refcount reaches zero. This procedure is invoked when + * an interpreter is deleted, via the AssocData cleanup mechanism. + * + * Results: + * None. + * + * Side effects: + * Deletes the hash table of channels. May close channels. May flush + * output on closed channels. Removes any channeEvent handlers that were + * registered in this interpreter. + * + *---------------------------------------------------------------------- + */ + +static void +DeleteReflectedChannelMap( + ClientData clientData, /* The per-interpreter data structure. */ + Tcl_Interp *interp) /* The interpreter being deleted. */ +{ + ReflectedChannelMap *rcmPtr = clientData; + /* The map */ + Tcl_HashSearch hSearch; /* Search variable. */ + Tcl_HashEntry *hPtr; /* Search variable. */ + ReflectedChannel *rcPtr; + Tcl_Channel chan; +#ifdef TCL_THREADS + ForwardingResult *resultPtr; + ForwardingEvent *evPtr; + ForwardParam *paramPtr; +#endif + + /* + * Delete all entries. The channels may have been closed already, or will + * be closed later, by the standard IO finalization of an interpreter + * under destruction. Except for the channels which were moved to a + * different interpreter and/or thread. They do not exist from the IO + * systems point of view and will not get closed. Therefore mark all as + * dead so that any future access will cause a proper error. For channels + * in a different thread we actually do the same as + * DeleteThreadReflectedChannelMap(), just restricted to the channels of + * this interp. + */ + + for (hPtr = Tcl_FirstHashEntry(&rcmPtr->map, &hSearch); + hPtr != NULL; + hPtr = Tcl_FirstHashEntry(&rcmPtr->map, &hSearch)) { + chan = Tcl_GetHashValue(hPtr); + rcPtr = Tcl_GetChannelInstanceData(chan); + + rcPtr->dead = 1; + Tcl_DeleteHashEntry(hPtr); + } + Tcl_DeleteHashTable(&rcmPtr->map); + ckfree(&rcmPtr->map); + +#ifdef TCL_THREADS + /* + * The origin interpreter for one or more reflected channels is gone. + */ + + /* + * Go through the list of pending results and cancel all whose events were + * destined for this interpreter. While this is in progress we block any + * other access to the list of pending results. + */ + + Tcl_MutexLock(&rcForwardMutex); + + for (resultPtr = forwardList; + resultPtr != NULL; + resultPtr = resultPtr->nextPtr) { + if (resultPtr->dsti != interp) { + /* + * Ignore results/events for other interpreters. + */ + + continue; + } + + /* + * The receiver for the event exited, before processing the event. We + * detach the result now, wake the originator up and signal failure. + */ + + evPtr = resultPtr->evPtr; + + /* Basic crash safety until this routine can get revised [3411310] */ + if (evPtr == NULL) { + continue; + } + paramPtr = evPtr->param; + + evPtr->resultPtr = NULL; + resultPtr->evPtr = NULL; + resultPtr->result = TCL_ERROR; + + ForwardSetStaticError(paramPtr, msg_send_dstlost); + + Tcl_ConditionNotify(&resultPtr->done); + } + Tcl_MutexUnlock(&rcForwardMutex); + + /* + * Get the map of all channels handled by the current thread. This is a + * ReflectedChannelMap, but on a per-thread basis, not per-interp. Go + * through the channels and remove all which were handled by this + * interpreter. They have already been marked as dead. + */ + + rcmPtr = GetThreadReflectedChannelMap(); + for (hPtr = Tcl_FirstHashEntry(&rcmPtr->map, &hSearch); + hPtr != NULL; + hPtr = Tcl_NextHashEntry(&hSearch)) { + chan = Tcl_GetHashValue(hPtr); + rcPtr = Tcl_GetChannelInstanceData(chan); + + if (rcPtr->interp != interp) { + /* + * Ignore entries for other interpreters. + */ + + continue; + } + + rcPtr->dead = 1; + Tcl_DeleteHashEntry(hPtr); + } +#endif +} + +#ifdef TCL_THREADS +/* + *---------------------------------------------------------------------- + * + * GetThreadReflectedChannelMap -- + * + * Gets and potentially initializes the reflected channel map for a + * thread. + * + * Results: + * A pointer to the map created, for use by the caller. + * + * Side effects: + * Initializes the reflected channel map for a thread. + * + *---------------------------------------------------------------------- + */ + +static ReflectedChannelMap * +GetThreadReflectedChannelMap(void) +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + if (!tsdPtr->rcmPtr) { + tsdPtr->rcmPtr = ckalloc(sizeof(ReflectedChannelMap)); + Tcl_InitHashTable(&tsdPtr->rcmPtr->map, TCL_STRING_KEYS); + Tcl_CreateThreadExitHandler(DeleteThreadReflectedChannelMap, NULL); + } + + return tsdPtr->rcmPtr; +} + +/* + *---------------------------------------------------------------------- + * + * DeleteThreadReflectedChannelMap -- + * + * Deletes the channel table for a thread. This procedure is invoked when + * a thread is deleted. The channels have already been marked as dead, in + * DeleteReflectedChannelMap(). + * + * Results: + * None. + * + * Side effects: + * Deletes the hash table of channels. + * + *---------------------------------------------------------------------- + */ + +static void +DeleteThreadReflectedChannelMap( + ClientData clientData) /* The per-thread data structure. */ +{ + Tcl_HashSearch hSearch; /* Search variable. */ + Tcl_HashEntry *hPtr; /* Search variable. */ + Tcl_ThreadId self = Tcl_GetCurrentThread(); + ReflectedChannelMap *rcmPtr; /* The map */ + ForwardingResult *resultPtr; + + /* + * The origin thread for one or more reflected channels is gone. + * NOTE: If this function is called due to a thread getting killed the + * per-interp DeleteReflectedChannelMap is apparently not called. + */ + + /* + * Go through the list of pending results and cancel all whose events were + * destined for this thread. While this is in progress we block any + * other access to the list of pending results. + */ + + Tcl_MutexLock(&rcForwardMutex); + + for (resultPtr = forwardList; + resultPtr != NULL; + resultPtr = resultPtr->nextPtr) { + ForwardingEvent *evPtr; + ForwardParam *paramPtr; + + if (resultPtr->dst != self) { + /* + * Ignore results/events for other threads. + */ + + continue; + } + + /* + * The receiver for the event exited, before processing the event. We + * detach the result now, wake the originator up and signal failure. + */ + + evPtr = resultPtr->evPtr; + + /* Basic crash safety until this routine can get revised [3411310] */ + if (evPtr == NULL ) { + continue; + } + paramPtr = evPtr->param; + + evPtr->resultPtr = NULL; + resultPtr->evPtr = NULL; + resultPtr->result = TCL_ERROR; + + ForwardSetStaticError(paramPtr, msg_send_dstlost); + + Tcl_ConditionNotify(&resultPtr->done); + } + Tcl_MutexUnlock(&rcForwardMutex); + + /* + * Run over the event queue of this thread and remove all ReflectEvent's + * still pending. These are inbound events for reflected channels this + * thread owns but doesn't handle. The inverse of the channel map + * actually. + */ + + Tcl_DeleteEvents(ReflectEventDelete, NULL); + + /* + * Get the map of all channels handled by the current thread. This is a + * ReflectedChannelMap, but on a per-thread basis, not per-interp. Go + * through the channels, remove all, mark them as dead. + */ + + rcmPtr = GetThreadReflectedChannelMap(); + for (hPtr = Tcl_FirstHashEntry(&rcmPtr->map, &hSearch); + hPtr != NULL; + hPtr = Tcl_FirstHashEntry(&rcmPtr->map, &hSearch)) { + Tcl_Channel chan = Tcl_GetHashValue(hPtr); + ReflectedChannel *rcPtr = Tcl_GetChannelInstanceData(chan); + + rcPtr->dead = 1; + Tcl_DeleteHashEntry(hPtr); + } + ckfree(rcmPtr); +} + +static void +ForwardOpToHandlerThread( + ReflectedChannel *rcPtr, /* Channel instance */ + ForwardedOperation op, /* Forwarded driver operation */ + const void *param) /* Arguments */ +{ + /* + * Core of the communication from OWNER to HANDLER thread. + * The receiver is ForwardProc() below. + */ + + Tcl_ThreadId dst = rcPtr->thread; + ForwardingEvent *evPtr; + ForwardingResult *resultPtr; + + /* + * We gather the lock early. This allows us to check the liveness of the + * channel without interference from DeleteThreadReflectedChannelMap(). + */ + + Tcl_MutexLock(&rcForwardMutex); + + if (rcPtr->dead) { + /* + * The channel is marked as dead. Bail out immediately, with an + * appropriate error. Do not forget to unlock the mutex on this path. + */ + + ForwardSetStaticError((ForwardParam *) param, msg_send_dstlost); + Tcl_MutexUnlock(&rcForwardMutex); + return; + } + + /* + * Create and initialize the event and data structures. + */ + + evPtr = ckalloc(sizeof(ForwardingEvent)); + resultPtr = ckalloc(sizeof(ForwardingResult)); + + evPtr->event.proc = ForwardProc; + evPtr->resultPtr = resultPtr; + evPtr->op = op; + evPtr->rcPtr = rcPtr; + evPtr->param = (ForwardParam *) param; + + resultPtr->src = Tcl_GetCurrentThread(); + resultPtr->dst = dst; + resultPtr->dsti = rcPtr->interp; + resultPtr->done = NULL; + resultPtr->result = -1; + resultPtr->evPtr = evPtr; + + /* + * Now execute the forward. + */ + + TclSpliceIn(resultPtr, forwardList); + /* Do not unlock here. That is done by the ConditionWait */ + + /* + * Ensure cleanup of the event if the origin thread exits while this event + * is pending or in progress. Exit of the destination thread is handled by + * DeleteThreadReflectedChannelMap(), this is set up by + * GetThreadReflectedChannelMap(). This is what we use the 'forwardList' + * (see above) for. + */ + + Tcl_CreateThreadExitHandler(SrcExitProc, evPtr); + + /* + * Queue the event and poke the other thread's notifier. + */ + + Tcl_ThreadQueueEvent(dst, (Tcl_Event *) evPtr, TCL_QUEUE_TAIL); + Tcl_ThreadAlert(dst); + + /* + * (*) Block until the handler thread has either processed the transfer or + * rejected it. + */ + + while (resultPtr->result < 0) { + /* + * NOTE (1): Is it possible that the current thread goes away while + * waiting here? IOW Is it possible that "SrcExitProc" is called while + * we are here? See complementary note (2) in "SrcExitProc" + * + * The ConditionWait unlocks the mutex during the wait and relocks it + * immediately after. + */ + + Tcl_ConditionWait(&resultPtr->done, &rcForwardMutex, NULL); + } + + /* + * Unlink result from the forwarder list. No need to lock. Either still + * locked, or locked by the ConditionWait + */ + + TclSpliceOut(resultPtr, forwardList); + + resultPtr->nextPtr = NULL; + resultPtr->prevPtr = NULL; + + Tcl_MutexUnlock(&rcForwardMutex); + Tcl_ConditionFinalize(&resultPtr->done); + + /* + * Kill the cleanup handler now, and the result structure as well, before + * returning the success code. + * + * Note: The event structure has already been deleted. + */ + + Tcl_DeleteThreadExitHandler(SrcExitProc, evPtr); + + ckfree(resultPtr); +} + +static int +ForwardProc( + Tcl_Event *evGPtr, + int mask) +{ + /* + * HANDLER thread. + + * The receiver part for the operations coming from the OWNER thread. + * See ForwardOpToHandlerThread() for the transmitter. + * + * Notes regarding access to the referenced data. + * + * In principle the data belongs to the originating thread (see + * evPtr->src), however this thread is currently blocked at (*), i.e. + * quiescent. Because of this we can treat the data as belonging to us, + * without fear of race conditions. I.e. we can read and write as we like. + * + * The only thing we cannot be sure of is the resultPtr. This can be be + * NULLed if the originating thread went away while the event is handled + * here now. + */ + + ForwardingEvent *evPtr = (ForwardingEvent *) evGPtr; + ForwardingResult *resultPtr = evPtr->resultPtr; + ReflectedChannel *rcPtr = evPtr->rcPtr; + Tcl_Interp *interp = rcPtr->interp; + ForwardParam *paramPtr = evPtr->param; + Tcl_Obj *resObj = NULL; /* Interp result of InvokeTclMethod */ + ReflectedChannelMap *rcmPtr;/* Map of reflected channels with handlers in + * this interp. */ + Tcl_HashEntry *hPtr; /* Entry in the above map */ + + /* + * Ignore the event if no one is waiting for its result anymore. + */ + + if (!resultPtr) { + return 1; + } + + paramPtr->base.code = TCL_OK; + paramPtr->base.msgStr = NULL; + paramPtr->base.mustFree = 0; + + switch (evPtr->op) { + /* + * The destination thread for the following operations is + * rcPtr->thread, which contains rcPtr->interp, the interp we have to + * call upon for the driver. + */ + + case ForwardedClose: + /* + * No parameters/results. + */ + + if (InvokeTclMethod(rcPtr, METH_FINAL, NULL, NULL, &resObj)!=TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + } + + /* + * Freeing is done here, in the origin thread, callback command + * objects belong to this thread. Deallocating them in a different + * thread is not allowed + * + * We remove the channel from both interpreter and thread maps before + * releasing the memory, to prevent future accesses (like by + * 'postevent') from finding and dereferencing a dangling pointer. + */ + + rcmPtr = GetReflectedChannelMap(interp); + hPtr = Tcl_FindHashEntry(&rcmPtr->map, + Tcl_GetChannelName(rcPtr->chan)); + Tcl_DeleteHashEntry(hPtr); + + rcmPtr = GetThreadReflectedChannelMap(); + hPtr = Tcl_FindHashEntry(&rcmPtr->map, + Tcl_GetChannelName(rcPtr->chan)); + Tcl_DeleteHashEntry(hPtr); + + Tcl_EventuallyFree(rcPtr, (Tcl_FreeProc *) FreeReflectedChannel); + break; + + case ForwardedInput: { + Tcl_Obj *toReadObj = Tcl_NewIntObj(paramPtr->input.toRead); + Tcl_IncrRefCount(toReadObj); + + Tcl_Preserve(rcPtr); + if (InvokeTclMethod(rcPtr, METH_READ, toReadObj, NULL, &resObj)!=TCL_OK){ + int code = ErrnoReturn(rcPtr, resObj); + + if (code < 0) { + paramPtr->base.code = code; + } else { + ForwardSetObjError(paramPtr, resObj); + } + paramPtr->input.toRead = -1; + } else { + /* + * Process a regular result. + */ + + int bytec; /* Number of returned bytes */ + unsigned char *bytev; /* Array of returned bytes */ + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + + if (paramPtr->input.toRead < bytec) { + ForwardSetStaticError(paramPtr, msg_read_toomuch); + paramPtr->input.toRead = -1; + } else { + if (bytec > 0) { + memcpy(paramPtr->input.buf, bytev, (size_t) bytec); + } + paramPtr->input.toRead = bytec; + } + } + Tcl_Release(rcPtr); + Tcl_DecrRefCount(toReadObj); + break; + } + + case ForwardedOutput: { + Tcl_Obj *bufObj = Tcl_NewByteArrayObj((unsigned char *) + paramPtr->output.buf, paramPtr->output.toWrite); + Tcl_IncrRefCount(bufObj); + + Tcl_Preserve(rcPtr); + if (InvokeTclMethod(rcPtr, METH_WRITE, bufObj, NULL, &resObj) != TCL_OK) { + int code = ErrnoReturn(rcPtr, resObj); + + if (code < 0) { + paramPtr->base.code = code; + } else { + ForwardSetObjError(paramPtr, resObj); + } + paramPtr->output.toWrite = -1; + } else { + /* + * Process a regular result. + */ + + int written; + + if (Tcl_GetIntFromObj(interp, resObj, &written) != TCL_OK) { + Tcl_DecrRefCount(resObj); + resObj = MarshallError(interp); + ForwardSetObjError(paramPtr, resObj); + paramPtr->output.toWrite = -1; + } else if (written==0 || paramPtr->output.toWrite<written) { + ForwardSetStaticError(paramPtr, msg_write_toomuch); + paramPtr->output.toWrite = -1; + } else { + paramPtr->output.toWrite = written; + } + } + Tcl_Release(rcPtr); + Tcl_DecrRefCount(bufObj); + break; + } + + case ForwardedSeek: { + Tcl_Obj *offObj = Tcl_NewWideIntObj(paramPtr->seek.offset); + Tcl_Obj *baseObj = Tcl_NewStringObj( + (paramPtr->seek.seekMode==SEEK_SET) ? "start" : + (paramPtr->seek.seekMode==SEEK_CUR) ? "current" : "end", -1); + + Tcl_IncrRefCount(offObj); + Tcl_IncrRefCount(baseObj); + + Tcl_Preserve(rcPtr); + if (InvokeTclMethod(rcPtr, METH_SEEK, offObj, baseObj, &resObj)!=TCL_OK){ + ForwardSetObjError(paramPtr, resObj); + paramPtr->seek.offset = -1; + } else { + /* + * Process a regular result. If the type is wrong this may change + * into an error. + */ + + Tcl_WideInt newLoc; + + if (Tcl_GetWideIntFromObj(interp, resObj, &newLoc) == TCL_OK) { + if (newLoc < Tcl_LongAsWide(0)) { + ForwardSetStaticError(paramPtr, msg_seek_beforestart); + paramPtr->seek.offset = -1; + } else { + paramPtr->seek.offset = newLoc; + } + } else { + Tcl_DecrRefCount(resObj); + resObj = MarshallError(interp); + ForwardSetObjError(paramPtr, resObj); + paramPtr->seek.offset = -1; + } + } + Tcl_Release(rcPtr); + Tcl_DecrRefCount(offObj); + Tcl_DecrRefCount(baseObj); + break; + } + + case ForwardedWatch: { + Tcl_Obj *maskObj = DecodeEventMask(paramPtr->watch.mask); + /* assert maskObj.refCount == 1 */ + + Tcl_Preserve(rcPtr); + (void) InvokeTclMethod(rcPtr, METH_WATCH, maskObj, NULL, NULL); + Tcl_DecrRefCount(maskObj); + Tcl_Release(rcPtr); + break; + } + + case ForwardedBlock: { + Tcl_Obj *blockObj = Tcl_NewBooleanObj(!paramPtr->block.nonblocking); + + Tcl_IncrRefCount(blockObj); + Tcl_Preserve(rcPtr); + if (InvokeTclMethod(rcPtr, METH_BLOCKING, blockObj, NULL, + &resObj) != TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + } + Tcl_Release(rcPtr); + Tcl_DecrRefCount(blockObj); + break; + } + + case ForwardedSetOpt: { + Tcl_Obj *optionObj = Tcl_NewStringObj(paramPtr->setOpt.name, -1); + Tcl_Obj *valueObj = Tcl_NewStringObj(paramPtr->setOpt.value, -1); + + Tcl_IncrRefCount(optionObj); + Tcl_IncrRefCount(valueObj); + Tcl_Preserve(rcPtr); + if (InvokeTclMethod(rcPtr, METH_CONFIGURE, optionObj, valueObj, + &resObj) != TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + } + Tcl_Release(rcPtr); + Tcl_DecrRefCount(optionObj); + Tcl_DecrRefCount(valueObj); + break; + } + + case ForwardedGetOpt: { + /* + * Retrieve the value of one option. + */ + + Tcl_Obj *optionObj = Tcl_NewStringObj(paramPtr->getOpt.name, -1); + + Tcl_IncrRefCount(optionObj); + Tcl_Preserve(rcPtr); + if (InvokeTclMethod(rcPtr, METH_CGET, optionObj, NULL, &resObj)!=TCL_OK){ + ForwardSetObjError(paramPtr, resObj); + } else { + TclDStringAppendObj(paramPtr->getOpt.value, resObj); + } + Tcl_Release(rcPtr); + Tcl_DecrRefCount(optionObj); + break; + } + + case ForwardedGetOptAll: + /* + * Retrieve all options. + */ + + Tcl_Preserve(rcPtr); + if (InvokeTclMethod(rcPtr, METH_CGETALL, NULL, NULL, &resObj) != TCL_OK){ + ForwardSetObjError(paramPtr, resObj); + } else { + /* + * Extract list, validate that it is a list, and #elements. See + * NOTE (4) as well. + */ + + int listc; + Tcl_Obj **listv; + + if (Tcl_ListObjGetElements(interp, resObj, &listc, + &listv) != TCL_OK) { + Tcl_DecrRefCount(resObj); + resObj = MarshallError(interp); + ForwardSetObjError(paramPtr, resObj); + } else if ((listc % 2) == 1) { + /* + * Odd number of elements is wrong. [x]. + */ + + char *buf = ckalloc(200); + sprintf(buf, + "{Expected list with even number of elements, got %d %s instead}", + listc, (listc == 1 ? "element" : "elements")); + + ForwardSetDynamicError(paramPtr, buf); + } else { + int len; + const char *str = Tcl_GetStringFromObj(resObj, &len); + + if (len) { + TclDStringAppendLiteral(paramPtr->getOpt.value, " "); + Tcl_DStringAppend(paramPtr->getOpt.value, str, len); + } + } + } + Tcl_Release(rcPtr); + break; + + default: + /* + * Bad operation code. + */ + + Tcl_Panic("Bad operation code in ForwardProc"); + break; + } + + /* + * Remove the reference we held on the result of the invoke, if we had + * such. + */ + + if (resObj != NULL) { + Tcl_DecrRefCount(resObj); + } + + if (resultPtr) { + /* + * Report the forwarding result synchronously to the waiting caller. + * This unblocks (*) as well. This is wrapped into a conditional + * because the caller may have exited in the mean time. + */ + + Tcl_MutexLock(&rcForwardMutex); + resultPtr->result = TCL_OK; + Tcl_ConditionNotify(&resultPtr->done); + Tcl_MutexUnlock(&rcForwardMutex); + } + + return 1; +} + +static void +SrcExitProc( + ClientData clientData) +{ + ForwardingEvent *evPtr = clientData; + ForwardingResult *resultPtr; + ForwardParam *paramPtr; + + /* + * NOTE (2): Can this handler be called with the originator blocked? + */ + + /* + * The originator for the event exited. It is not sure if this can happen, + * as the originator should be blocked at (*) while the event is in + * transit/pending. + * + * We make sure that the event cannot refer to the result anymore, remove + * it from the list of pending results and free the structure. Locking the + * access ensures that we cannot get in conflict with "ForwardProc", + * should it already execute the event. + */ + + Tcl_MutexLock(&rcForwardMutex); + + resultPtr = evPtr->resultPtr; + paramPtr = evPtr->param; + + evPtr->resultPtr = NULL; + resultPtr->evPtr = NULL; + resultPtr->result = TCL_ERROR; + + ForwardSetStaticError(paramPtr, msg_send_originlost); + + /* + * See below: TclSpliceOut(resultPtr, forwardList); + */ + + Tcl_MutexUnlock(&rcForwardMutex); + + /* + * This unlocks (*). The structure will be spliced out and freed by + * "ForwardProc". Maybe. + */ + + Tcl_ConditionNotify(&resultPtr->done); +} + +static void +ForwardSetObjError( + ForwardParam *paramPtr, + Tcl_Obj *obj) +{ + int len; + const char *msgStr = Tcl_GetStringFromObj(obj, &len); + + len++; + ForwardSetDynamicError(paramPtr, ckalloc(len)); + memcpy(paramPtr->base.msgStr, msgStr, (unsigned) len); +} +#endif + +/* + * Local Variables: + * mode: c + * c-basic-offset: 4 + * fill-column: 78 + * tab-width: 8 + * indent-tabs-mode: nil + * End: + */ |