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-rw-r--r--unix/tclLoadAix.c630
1 files changed, 630 insertions, 0 deletions
diff --git a/unix/tclLoadAix.c b/unix/tclLoadAix.c
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+/*
+ * tclLoadAix.c --
+ *
+ * This file implements the dlopen and dlsym APIs under the AIX operating
+ * system, to enable the Tcl "load" command to work. This code was
+ * provided by Jens-Uwe Mager.
+ *
+ * This file is subject to the following copyright notice, which is
+ * different from the notice used elsewhere in Tcl. The file has been
+ * modified to incorporate the file dlfcn.h in-line.
+ *
+ * Copyright (c) 1992,1993,1995,1996, Jens-Uwe Mager, Helios Software GmbH
+ * Not derived from licensed software.
+ *
+ * Permission is granted to freely use, copy, modify, and redistribute
+ * this software, provided that the author is not construed to be liable
+ * for any results of using the software, alterations are clearly marked
+ * as such, and this notice is not modified.
+ *
+ * Note: this file has been altered from the original in a few ways in order
+ * to work properly with Tcl.
+ */
+
+/*
+ * @(#)dlfcn.c 1.7 revision of 95/08/14 19:08:38
+ * This is an unpublished work copyright (c) 1992 HELIOS Software GmbH
+ * 30159 Hannover, Germany
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/ldr.h>
+#include <a.out.h>
+#include <ldfcn.h>
+#include "../compat/dlfcn.h"
+
+/*
+ * We simulate dlopen() et al. through a call to load. Because AIX has no call
+ * to find an exported symbol we read the loader section of the loaded module
+ * and build a list of exported symbols and their virtual address.
+ */
+
+typedef struct {
+ char *name; /* The symbols's name. */
+ void *addr; /* Its relocated virtual address. */
+} Export, *ExportPtr;
+
+/*
+ * xlC uses the following structure to list its constructors and destructors.
+ * This is gleaned from the output of munch.
+ */
+
+typedef struct {
+ void (*init)(void); /* call static constructors */
+ void (*term)(void); /* call static destructors */
+} Cdtor, *CdtorPtr;
+
+/*
+ * The void * handle returned from dlopen is actually a ModulePtr.
+ */
+
+typedef struct Module {
+ struct Module *next;
+ char *name; /* module name for refcounting */
+ int refCnt; /* the number of references */
+ void *entry; /* entry point from load */
+ struct dl_info *info; /* optional init/terminate functions */
+ CdtorPtr cdtors; /* optional C++ constructors */
+ int nExports; /* the number of exports found */
+ ExportPtr exports; /* the array of exports */
+} Module, *ModulePtr;
+
+/*
+ * We keep a list of all loaded modules to be able to call the fini handlers
+ * and destructors at atexit() time.
+ */
+
+static ModulePtr modList;
+
+/*
+ * The last error from one of the dl* routines is kept in static variables
+ * here. Each error is returned only once to the caller.
+ */
+
+static char errbuf[BUFSIZ];
+static int errvalid;
+
+static void caterr(char *);
+static int readExports(ModulePtr);
+static void terminate(void);
+static void *findMain(void);
+
+void *
+dlopen(
+ const char *path,
+ int mode)
+{
+ register ModulePtr mp;
+ static void *mainModule;
+
+ /*
+ * Upon the first call register a terminate handler that will close all
+ * libraries. Also get a reference to the main module for use with
+ * loadbind.
+ */
+
+ if (!mainModule) {
+ mainModule = findMain();
+ if (mainModule == NULL) {
+ return NULL;
+ }
+ atexit(terminate);
+ }
+
+ /*
+ * Scan the list of modules if we have the module already loaded.
+ */
+
+ for (mp = modList; mp; mp = mp->next) {
+ if (strcmp(mp->name, path) == 0) {
+ mp->refCnt++;
+ return (void *) mp;
+ }
+ }
+
+ mp = (ModulePtr) calloc(1, sizeof(*mp));
+ if (mp == NULL) {
+ errvalid++;
+ strcpy(errbuf, "calloc: ");
+ strcat(errbuf, strerror(errno));
+ return NULL;
+ }
+
+ mp->name = malloc((unsigned) (strlen(path) + 1));
+ strcpy(mp->name, path);
+
+ /*
+ * load should be declared load(const char *...). Thus we cast the path to
+ * a normal char *. Ugly.
+ */
+
+ mp->entry = (void *) load((char *)path, L_NOAUTODEFER, NULL);
+ if (mp->entry == NULL) {
+ free(mp->name);
+ free(mp);
+ errvalid++;
+ strcpy(errbuf, "dlopen: ");
+ strcat(errbuf, path);
+ strcat(errbuf, ": ");
+
+ /*
+ * If AIX says the file is not executable, the error can be further
+ * described by querying the loader about the last error.
+ */
+
+ if (errno == ENOEXEC) {
+ char *tmp[BUFSIZ/sizeof(char *)], **p;
+
+ if (loadquery(L_GETMESSAGES, tmp, sizeof(tmp)) == -1) {
+ strcpy(errbuf, strerror(errno));
+ } else {
+ for (p=tmp ; *p ; p++) {
+ caterr(*p);
+ }
+ }
+ } else {
+ strcat(errbuf, strerror(errno));
+ }
+ return NULL;
+ }
+
+ mp->refCnt = 1;
+ mp->next = modList;
+ modList = mp;
+
+ if (loadbind(0, mainModule, mp->entry) == -1) {
+ loadbindFailure:
+ dlclose(mp);
+ errvalid++;
+ strcpy(errbuf, "loadbind: ");
+ strcat(errbuf, strerror(errno));
+ return NULL;
+ }
+
+ /*
+ * If the user wants global binding, loadbind against all other loaded
+ * modules.
+ */
+
+ if (mode & RTLD_GLOBAL) {
+ register ModulePtr mp1;
+
+ for (mp1 = mp->next; mp1; mp1 = mp1->next) {
+ if (loadbind(0, mp1->entry, mp->entry) == -1) {
+ goto loadbindFailure;
+ }
+ }
+ }
+
+ if (readExports(mp) == -1) {
+ dlclose(mp);
+ return NULL;
+ }
+
+ /*
+ * If there is a dl_info structure, call the init function.
+ */
+
+ if (mp->info = (struct dl_info *)dlsym(mp, "dl_info")) {
+ if (mp->info->init) {
+ mp->info->init();
+ }
+ } else {
+ errvalid = 0;
+ }
+
+ /*
+ * If the shared object was compiled using xlC we will need to call static
+ * constructors (and later on dlclose destructors).
+ */
+
+ if (mp->cdtors = (CdtorPtr) dlsym(mp, "__cdtors")) {
+ while (mp->cdtors->init) {
+ mp->cdtors->init();
+ mp->cdtors++;
+ }
+ } else {
+ errvalid = 0;
+ }
+
+ return (void *) mp;
+}
+
+/*
+ * Attempt to decipher an AIX loader error message and append it to our static
+ * error message buffer.
+ */
+
+static void
+caterr(
+ char *s)
+{
+ register char *p = s;
+
+ while (*p >= '0' && *p <= '9') {
+ p++;
+ }
+ switch (atoi(s)) { /* INTL: "C", UTF safe. */
+ case L_ERROR_TOOMANY:
+ strcat(errbuf, "to many errors");
+ break;
+ case L_ERROR_NOLIB:
+ strcat(errbuf, "can't load library");
+ strcat(errbuf, p);
+ break;
+ case L_ERROR_UNDEF:
+ strcat(errbuf, "can't find symbol");
+ strcat(errbuf, p);
+ break;
+ case L_ERROR_RLDBAD:
+ strcat(errbuf, "bad RLD");
+ strcat(errbuf, p);
+ break;
+ case L_ERROR_FORMAT:
+ strcat(errbuf, "bad exec format in");
+ strcat(errbuf, p);
+ break;
+ case L_ERROR_ERRNO:
+ strcat(errbuf, strerror(atoi(++p))); /* INTL: "C", UTF safe. */
+ break;
+ default:
+ strcat(errbuf, s);
+ break;
+ }
+}
+
+void *
+dlsym(
+ void *handle,
+ const char *symbol)
+{
+ register ModulePtr mp = (ModulePtr)handle;
+ register ExportPtr ep;
+ register int i;
+
+ /*
+ * Could speed up the search, but I assume that one assigns the result to
+ * function pointers anyways.
+ */
+
+ for (ep = mp->exports, i = mp->nExports; i; i--, ep++) {
+ if (strcmp(ep->name, symbol) == 0) {
+ return ep->addr;
+ }
+ }
+
+ errvalid++;
+ strcpy(errbuf, "dlsym: undefined symbol ");
+ strcat(errbuf, symbol);
+ return NULL;
+}
+
+char *
+dlerror(void)
+{
+ if (errvalid) {
+ errvalid = 0;
+ return errbuf;
+ }
+ return NULL;
+}
+
+int
+dlclose(
+ void *handle)
+{
+ register ModulePtr mp = (ModulePtr)handle;
+ int result;
+ register ModulePtr mp1;
+
+ if (--mp->refCnt > 0) {
+ return 0;
+ }
+
+ if (mp->info && mp->info->fini) {
+ mp->info->fini();
+ }
+
+ if (mp->cdtors) {
+ while (mp->cdtors->term) {
+ mp->cdtors->term();
+ mp->cdtors++;
+ }
+ }
+
+ result = unload(mp->entry);
+ if (result == -1) {
+ errvalid++;
+ strcpy(errbuf, strerror(errno));
+ }
+
+ if (mp->exports) {
+ register ExportPtr ep;
+ register int i;
+ for (ep = mp->exports, i = mp->nExports; i; i--, ep++) {
+ if (ep->name) {
+ free(ep->name);
+ }
+ }
+ free(mp->exports);
+ }
+
+ if (mp == modList) {
+ modList = mp->next;
+ } else {
+ for (mp1 = modList; mp1; mp1 = mp1->next) {
+ if (mp1->next == mp) {
+ mp1->next = mp->next;
+ break;
+ }
+ }
+ }
+
+ free(mp->name);
+ free(mp);
+ return result;
+}
+
+static void
+terminate(void)
+{
+ while (modList) {
+ dlclose(modList);
+ }
+}
+
+/*
+ * Build the export table from the XCOFF .loader section.
+ */
+
+static int
+readExports(
+ ModulePtr mp)
+{
+ LDFILE *ldp = NULL;
+ SCNHDR sh, shdata;
+ LDHDR *lhp;
+ char *ldbuf;
+ LDSYM *ls;
+ int i;
+ ExportPtr ep;
+ const char *errMsg;
+
+#define Error(msg) do{errMsg=(msg);goto error;}while(0)
+#define SysErr() Error(strerror(errno))
+
+ ldp = ldopen(mp->name, ldp);
+ if (ldp == NULL) {
+ struct ld_info *lp;
+ char *buf;
+ int size = 0;
+
+ if (errno != ENOENT) {
+ SysErr();
+ }
+
+ /*
+ * The module might be loaded due to the LIBPATH environment variable.
+ * Search for the loaded module using L_GETINFO.
+ */
+
+ while (1) {
+ size += 4 * 1024;
+ buf = malloc(size);
+ if (buf == NULL) {
+ SysErr();
+ }
+
+ i = loadquery(L_GETINFO, buf, size);
+
+ if (i != -1) {
+ break;
+ }
+ free(buf);
+ if (errno != ENOMEM) {
+ SysErr();
+ }
+ }
+
+ /*
+ * Traverse the list of loaded modules. The entry point returned by
+ * load() does actually point to the data segment origin.
+ */
+
+ lp = (struct ld_info *) buf;
+ while (lp) {
+ if (lp->ldinfo_dataorg == mp->entry) {
+ ldp = ldopen(lp->ldinfo_filename, ldp);
+ break;
+ }
+ if (lp->ldinfo_next == 0) {
+ lp = NULL;
+ } else {
+ lp = (struct ld_info *)((char *)lp + lp->ldinfo_next);
+ }
+ }
+
+ free(buf);
+
+ if (!ldp) {
+ SysErr();
+ }
+ }
+
+ if (TYPE(ldp) != U802TOCMAGIC) {
+ Error("bad magic");
+ }
+
+ /*
+ * Get the padding for the data section. This is needed for AIX 4.1
+ * compilers. This is used when building the final function pointer to the
+ * exported symbol.
+ */
+
+ if (ldnshread(ldp, _DATA, &shdata) != SUCCESS) {
+ Error("cannot read data section header");
+ }
+
+ if (ldnshread(ldp, _LOADER, &sh) != SUCCESS) {
+ Error("cannot read loader section header");
+ }
+
+ /*
+ * We read the complete loader section in one chunk, this makes finding
+ * long symbol names residing in the string table easier.
+ */
+
+ ldbuf = (char *) malloc(sh.s_size);
+ if (ldbuf == NULL) {
+ SysErr();
+ }
+
+ if (FSEEK(ldp, sh.s_scnptr, BEGINNING) != OKFSEEK) {
+ free(ldbuf);
+ Error("cannot seek to loader section");
+ }
+
+ if (FREAD(ldbuf, sh.s_size, 1, ldp) != 1) {
+ free(ldbuf);
+ Error("cannot read loader section");
+ }
+
+ lhp = (LDHDR *) ldbuf;
+ ls = (LDSYM *)(ldbuf + LDHDRSZ);
+
+ /*
+ * Count the number of exports to include in our export table.
+ */
+
+ for (i = lhp->l_nsyms; i; i--, ls++) {
+ if (!LDR_EXPORT(*ls)) {
+ continue;
+ }
+ mp->nExports++;
+ }
+
+ mp->exports = (ExportPtr) calloc(mp->nExports, sizeof(*mp->exports));
+ if (mp->exports == NULL) {
+ free(ldbuf);
+ SysErr();
+ }
+
+ /*
+ * Fill in the export table. All entries are relative to the entry point
+ * we got from load.
+ */
+
+ ep = mp->exports;
+ ls = (LDSYM *)(ldbuf + LDHDRSZ);
+ for (i=lhp->l_nsyms ; i!=0 ; i--,ls++) {
+ char *symname;
+ char tmpsym[SYMNMLEN+1];
+
+ if (!LDR_EXPORT(*ls)) {
+ continue;
+ }
+
+ if (ls->l_zeroes == 0) {
+ symname = ls->l_offset + lhp->l_stoff + ldbuf;
+ } else {
+ /*
+ * The l_name member is not zero terminated, we must copy the
+ * first SYMNMLEN chars and make sure we have a zero byte at the
+ * end.
+ */
+
+ strncpy(tmpsym, ls->l_name, SYMNMLEN);
+ tmpsym[SYMNMLEN] = '\0';
+ symname = tmpsym;
+ }
+ ep->name = malloc((unsigned) (strlen(symname) + 1));
+ strcpy(ep->name, symname);
+ ep->addr = (void *)((unsigned long)
+ mp->entry + ls->l_value - shdata.s_vaddr);
+ ep++;
+ }
+ free(ldbuf);
+ while (ldclose(ldp) == FAILURE) {
+ /* Empty body */
+ }
+ return 0;
+
+ /*
+ * This is a factoring out of the error-handling code to make the rest of
+ * the function much simpler to read.
+ */
+
+ error:
+ errvalid++;
+ strcpy(errbuf, "readExports: ");
+ strcat(errbuf, errMsg);
+
+ if (ldp != NULL) {
+ while (ldclose(ldp) == FAILURE) {
+ /* Empty body */
+ }
+ }
+ return -1;
+}
+
+/*
+ * Find the main modules entry point. This is used as export pointer for
+ * loadbind() to be able to resolve references to the main part.
+ */
+
+static void *
+findMain(void)
+{
+ struct ld_info *lp;
+ char *buf;
+ int size = 4*1024;
+ int i;
+ void *ret;
+
+ buf = malloc(size);
+ if (buf == NULL) {
+ goto error;
+ }
+
+ while ((i = loadquery(L_GETINFO, buf, size)) == -1 && errno == ENOMEM) {
+ free(buf);
+ size += 4*1024;
+ buf = malloc(size);
+ if (buf == NULL) {
+ goto error;
+ }
+ }
+
+ if (i == -1) {
+ free(buf);
+ goto error;
+ }
+
+ /*
+ * The first entry is the main module. The entry point returned by load()
+ * does actually point to the data segment origin.
+ */
+
+ lp = (struct ld_info *) buf;
+ ret = lp->ldinfo_dataorg;
+ free(buf);
+ return ret;
+
+ error:
+ errvalid++;
+ strcpy(errbuf, "findMain: ");
+ strcat(errbuf, strerror(errno));
+ return NULL;
+}
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */
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