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-rw-r--r--unix/tclLoadAix.c549
1 files changed, 549 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.
+ *
+ * SCCS: @(#) tclLoadAix.c 1.11 96/10/07 10:41:24
+ *
+ * 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+ * This is an unpublished work copyright (c) 1992 HELIOS Software GmbH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) {
+ if ((mainModule = findMain()) == 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;
+ }
+ if ((mp = (ModulePtr)calloc(1, sizeof(*mp))) == NULL) {
+ errvalid++;
+ strcpy(errbuf, "calloc: ");
+ strcat(errbuf, strerror(errno));
+ return (VOID *) 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.
+ */
+ if ((mp->entry = (void *)load((char *)path, L_NOAUTODEFER, NULL)) == 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 *)];
+ if (loadquery(L_GETMESSAGES, tmp, sizeof(tmp)) == -1)
+ strcpy(errbuf, strerror(errno));
+ else {
+ char **p;
+ for (p = tmp; *p; p++)
+ caterr(*p);
+ }
+ } else
+ strcat(errbuf, strerror(errno));
+ return (VOID *) NULL;
+ }
+ mp->refCnt = 1;
+ mp->next = modList;
+ modList = mp;
+ if (loadbind(0, mainModule, mp->entry) == -1) {
+ dlclose(mp);
+ errvalid++;
+ strcpy(errbuf, "loadbind: ");
+ strcat(errbuf, strerror(errno));
+ return (VOID *) 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) {
+ dlclose(mp);
+ errvalid++;
+ strcpy(errbuf, "loadbind: ");
+ strcat(errbuf, strerror(errno));
+ return (VOID *) NULL;
+ }
+ }
+ if (readExports(mp) == -1) {
+ dlclose(mp);
+ return (VOID *) 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)) {
+ 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)));
+ 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;
+
+ if ((ldp = ldopen(mp->name, ldp)) == NULL) {
+ struct ld_info *lp;
+ char *buf;
+ int size = 4*1024;
+ if (errno != ENOENT) {
+ errvalid++;
+ strcpy(errbuf, "readExports: ");
+ strcat(errbuf, strerror(errno));
+ return -1;
+ }
+ /*
+ * The module might be loaded due to the LIBPATH
+ * environment variable. Search for the loaded
+ * module using L_GETINFO.
+ */
+ if ((buf = malloc(size)) == NULL) {
+ errvalid++;
+ strcpy(errbuf, "readExports: ");
+ strcat(errbuf, strerror(errno));
+ return -1;
+ }
+ while ((i = loadquery(L_GETINFO, buf, size)) == -1 && errno == ENOMEM) {
+ free(buf);
+ size += 4*1024;
+ if ((buf = malloc(size)) == NULL) {
+ errvalid++;
+ strcpy(errbuf, "readExports: ");
+ strcat(errbuf, strerror(errno));
+ return -1;
+ }
+ }
+ if (i == -1) {
+ errvalid++;
+ strcpy(errbuf, "readExports: ");
+ strcat(errbuf, strerror(errno));
+ free(buf);
+ return -1;
+ }
+ /*
+ * 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) {
+ errvalid++;
+ strcpy(errbuf, "readExports: ");
+ strcat(errbuf, strerror(errno));
+ return -1;
+ }
+ }
+ if (TYPE(ldp) != U802TOCMAGIC) {
+ errvalid++;
+ strcpy(errbuf, "readExports: bad magic");
+ while(ldclose(ldp) == FAILURE)
+ ;
+ return -1;
+ }
+ /*
+ * 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) {
+ errvalid++;
+ strcpy(errbuf, "readExports: cannot read data section header");
+ while(ldclose(ldp) == FAILURE)
+ ;
+ return -1;
+ }
+ if (ldnshread(ldp, _LOADER, &sh) != SUCCESS) {
+ errvalid++;
+ strcpy(errbuf, "readExports: cannot read loader section header");
+ while(ldclose(ldp) == FAILURE)
+ ;
+ return -1;
+ }
+ /*
+ * We read the complete loader section in one chunk, this makes
+ * finding long symbol names residing in the string table easier.
+ */
+ if ((ldbuf = (char *)malloc(sh.s_size)) == NULL) {
+ errvalid++;
+ strcpy(errbuf, "readExports: ");
+ strcat(errbuf, strerror(errno));
+ while(ldclose(ldp) == FAILURE)
+ ;
+ return -1;
+ }
+ if (FSEEK(ldp, sh.s_scnptr, BEGINNING) != OKFSEEK) {
+ errvalid++;
+ strcpy(errbuf, "readExports: cannot seek to loader section");
+ free(ldbuf);
+ while(ldclose(ldp) == FAILURE)
+ ;
+ return -1;
+ }
+ if (FREAD(ldbuf, sh.s_size, 1, ldp) != 1) {
+ errvalid++;
+ strcpy(errbuf, "readExports: cannot read loader section");
+ free(ldbuf);
+ while(ldclose(ldp) == FAILURE)
+ ;
+ return -1;
+ }
+ 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++;
+ }
+ if ((mp->exports = (ExportPtr)calloc(mp->nExports, sizeof(*mp->exports))) == NULL) {
+ errvalid++;
+ strcpy(errbuf, "readExports: ");
+ strcat(errbuf, strerror(errno));
+ free(ldbuf);
+ while(ldclose(ldp) == FAILURE)
+ ;
+ return -1;
+ }
+ /*
+ * 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; 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)
+ ;
+ return 0;
+}
+
+/*
+ * 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;
+
+ if ((buf = malloc(size)) == NULL) {
+ errvalid++;
+ strcpy(errbuf, "findMain: ");
+ strcat(errbuf, strerror(errno));
+ return NULL;
+ }
+ while ((i = loadquery(L_GETINFO, buf, size)) == -1 && errno == ENOMEM) {
+ free(buf);
+ size += 4*1024;
+ if ((buf = malloc(size)) == NULL) {
+ errvalid++;
+ strcpy(errbuf, "findMain: ");
+ strcat(errbuf, strerror(errno));
+ return NULL;
+ }
+ }
+ if (i == -1) {
+ errvalid++;
+ strcpy(errbuf, "findMain: ");
+ strcat(errbuf, strerror(errno));
+ free(buf);
+ return NULL;
+ }
+ /*
+ * 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;
+}
+
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