diff options
Diffstat (limited to 'compat/waitpid.c')
| -rw-r--r-- | compat/waitpid.c | 93 |
1 files changed, 45 insertions, 48 deletions
diff --git a/compat/waitpid.c b/compat/waitpid.c index 365d51e..0e9e6d6 100644 --- a/compat/waitpid.c +++ b/compat/waitpid.c @@ -1,18 +1,17 @@ /* * waitpid.c -- * - * This procedure emulates the POSIX waitpid kernel call on - * BSD systems that don't have waitpid but do have wait3. - * This code is based on a prototype version written by - * Mark Diekhans and Karl Lehenbauer. + * This procedure emulates the POSIX waitpid kernel call on BSD systems + * that don't have waitpid but do have wait3. This code is based on a + * prototype version written by Mark Diekhans and Karl Lehenbauer. * * Copyright (c) 1993 The Regents of the University of California. * Copyright (c) 1994 Sun Microsystems, Inc. * - * See the file "license.terms" for information on usage and redistribution - * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * See the file "license.terms" for information on usage and redistribution of + * this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: waitpid.c,v 1.4 2004/04/06 22:25:48 dgp Exp $ + * RCS: @(#) $Id: waitpid.c,v 1.5 2007/04/16 13:36:35 dkf Exp $ */ #include "tclPort.h" @@ -22,40 +21,37 @@ #endif /* - * A linked list of the following structures is used to keep track - * of processes for which we received notification from the kernel, - * but the application hasn't waited for them yet (this can happen - * because wait may not return the process we really want). We - * save the information here until the application finally does - * wait for the process. + * A linked list of the following structures is used to keep track of + * processes for which we received notification from the kernel, but the + * application hasn't waited for them yet (this can happen because wait may + * not return the process we really want). We save the information here until + * the application finally does wait for the process. */ typedef struct WaitInfo { - pid_t pid; /* Pid of process that exited. */ - WAIT_STATUS_TYPE status; /* Status returned when child exited - * or suspended. */ - struct WaitInfo *nextPtr; /* Next in list of exited processes. */ + pid_t pid; /* Pid of process that exited. */ + WAIT_STATUS_TYPE status; /* Status returned when child exited or + * suspended. */ + struct WaitInfo *nextPtr; /* Next in list of exited processes. */ } WaitInfo; -static WaitInfo *deadList = NULL; /* First in list of all dead - * processes. */ +static WaitInfo *deadList = NULL; + /* First in list of all dead processes. */ /* *---------------------------------------------------------------------- * * waitpid -- * - * This procedure emulates the functionality of the POSIX - * waitpid kernel call, using the BSD wait3 kernel call. - * Note: it doesn't emulate absolutely all of the waitpid - * functionality, in that it doesn't support pid's of 0 - * or < -1. + * This procedure emulates the functionality of the POSIX waitpid kernel + * call, using the BSD wait3 kernel call. Note: it doesn't emulate + * absolutely all of the waitpid functionality, in that it doesn't + * support pid's of 0 or < -1. * * Results: - * -1 is returned if there is an error in the wait kernel call. - * Otherwise the pid of an exited or suspended process is - * returned and *statusPtr is set to the status value of the - * process. + * -1 is returned if there is an error in the wait kernel call. Otherwise + * the pid of an exited or suspended process is returned and *statusPtr + * is set to the status value of the process. * * Side effects: * None. @@ -68,12 +64,12 @@ static WaitInfo *deadList = NULL; /* First in list of all dead #endif pid_t -waitpid(pid, statusPtr, options) - pid_t pid; /* The pid to wait on. Must be -1 or - * greater than zero. */ - int *statusPtr; /* Where to store wait status for the +waitpid( + pid_t pid, /* The pid to wait on. Must be -1 or greater + * than zero. */ + int *statusPtr, /* Where to store wait status for the * process. */ - int options; /* OR'ed combination of WNOHANG and + int options) /* OR'ed combination of WNOHANG and * WUNTRACED. */ { register WaitInfo *waitPtr, *prevPtr; @@ -86,9 +82,9 @@ waitpid(pid, statusPtr, options) } /* - * See if there's a suitable process that has already stopped or - * exited. If so, remove it from the list of exited processes and - * return its information. + * See if there's a suitable process that has already stopped or exited. + * If so, remove it from the list of exited processes and return its + * information. */ for (waitPtr = deadList, prevPtr = NULL; waitPtr != NULL; @@ -111,12 +107,12 @@ waitpid(pid, statusPtr, options) } /* - * Wait for any process to stop or exit. If it's an acceptable one - * then return it to the caller; otherwise store information about it - * in the list of exited processes and try again. On systems that - * have only wait but not wait3, there are several situations we can't - * handle, but we do the best we can (e.g. can still handle some - * combinations of options by invoking wait instead of wait3). + * Wait for any process to stop or exit. If it's an acceptable one then + * return it to the caller; otherwise store information about it in the + * list of exited processes and try again. On systems that have only wait + * but not wait3, there are several situations we can't handle, but we do + * the best we can (e.g. can still handle some combinations of options by + * invoking wait instead of wait3). */ while (1) { @@ -149,13 +145,13 @@ waitpid(pid, statusPtr, options) return result; /* - * Can't return this info to caller. Save it in the list of - * stopped or exited processes. Tricky point: first check for - * an existing entry for the process and overwrite it if it - * exists (e.g. a previously stopped process might now be dead). + * Can't return this info to caller. Save it in the list of stopped or + * exited processes. Tricky point: first check for an existing entry + * for the process and overwrite it if it exists (e.g. a previously + * stopped process might now be dead). */ - saveInfo: + saveInfo: for (waitPtr = deadList; waitPtr != NULL; waitPtr = waitPtr->nextPtr) { if (waitPtr->pid == result) { waitPtr->status = status; @@ -168,6 +164,7 @@ waitpid(pid, statusPtr, options) waitPtr->nextPtr = deadList; deadList = waitPtr; - waitAgain: continue; + waitAgain: + continue; } } |