550 lines
13 KiB
C
550 lines
13 KiB
C
/*
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* tclLoadAix.c --
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*
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* This file implements the dlopen and dlsym APIs under the
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* AIX operating system, to enable the Tcl "load" command to
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* work. This code was provided by Jens-Uwe Mager.
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*
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* This file is subject to the following copyright notice, which is
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* different from the notice used elsewhere in Tcl. The file has
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* been modified to incorporate the file dlfcn.h in-line.
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*
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* Copyright (c) 1992,1993,1995,1996, Jens-Uwe Mager, Helios Software GmbH
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* Not derived from licensed software.
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* Permission is granted to freely use, copy, modify, and redistribute
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* this software, provided that the author is not construed to be liable
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* for any results of using the software, alterations are clearly marked
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* as such, and this notice is not modified.
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*
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* SCCS: @(#) tclLoadAix.c 1.11 96/10/07 10:41:24
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*
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* Note: this file has been altered from the original in a few
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* ways in order to work properly with Tcl.
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*/
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/*
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* @(#)dlfcn.c 1.7 revision of 95/08/14 19:08:38
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* This is an unpublished work copyright (c) 1992 HELIOS Software GmbH
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* 30159 Hannover, Germany
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*/
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/ldr.h>
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#include <a.out.h>
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#include <ldfcn.h>
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#include "../compat/dlfcn.h"
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/*
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* We simulate dlopen() et al. through a call to load. Because AIX has
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* no call to find an exported symbol we read the loader section of the
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* loaded module and build a list of exported symbols and their virtual
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* address.
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*/
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typedef struct {
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char *name; /* the symbols's name */
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void *addr; /* its relocated virtual address */
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} Export, *ExportPtr;
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/*
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* xlC uses the following structure to list its constructors and
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* destructors. This is gleaned from the output of munch.
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*/
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typedef struct {
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void (*init)(void); /* call static constructors */
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void (*term)(void); /* call static destructors */
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} Cdtor, *CdtorPtr;
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/*
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* The void * handle returned from dlopen is actually a ModulePtr.
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*/
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typedef struct Module {
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struct Module *next;
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char *name; /* module name for refcounting */
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int refCnt; /* the number of references */
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void *entry; /* entry point from load */
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struct dl_info *info; /* optional init/terminate functions */
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CdtorPtr cdtors; /* optional C++ constructors */
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int nExports; /* the number of exports found */
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ExportPtr exports; /* the array of exports */
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} Module, *ModulePtr;
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/*
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* We keep a list of all loaded modules to be able to call the fini
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* handlers and destructors at atexit() time.
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*/
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static ModulePtr modList;
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/*
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* The last error from one of the dl* routines is kept in static
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* variables here. Each error is returned only once to the caller.
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*/
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static char errbuf[BUFSIZ];
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static int errvalid;
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static void caterr(char *);
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static int readExports(ModulePtr);
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static void terminate(void);
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static void *findMain(void);
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VOID *dlopen(const char *path, int mode)
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{
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register ModulePtr mp;
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static void *mainModule;
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/*
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* Upon the first call register a terminate handler that will
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* close all libraries. Also get a reference to the main module
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* for use with loadbind.
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*/
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if (!mainModule) {
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if ((mainModule = findMain()) == NULL)
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return NULL;
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atexit(terminate);
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}
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/*
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* Scan the list of modules if we have the module already loaded.
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*/
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for (mp = modList; mp; mp = mp->next)
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if (strcmp(mp->name, path) == 0) {
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mp->refCnt++;
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return (VOID *) mp;
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}
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if ((mp = (ModulePtr)calloc(1, sizeof(*mp))) == NULL) {
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errvalid++;
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strcpy(errbuf, "calloc: ");
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strcat(errbuf, strerror(errno));
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return (VOID *) NULL;
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}
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mp->name = malloc((unsigned) (strlen(path) + 1));
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strcpy(mp->name, path);
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/*
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* load should be declared load(const char *...). Thus we
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* cast the path to a normal char *. Ugly.
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*/
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if ((mp->entry = (void *)load((char *)path, L_NOAUTODEFER, NULL)) == NULL) {
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free(mp->name);
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free(mp);
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errvalid++;
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strcpy(errbuf, "dlopen: ");
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strcat(errbuf, path);
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strcat(errbuf, ": ");
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/*
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* If AIX says the file is not executable, the error
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* can be further described by querying the loader about
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* the last error.
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*/
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if (errno == ENOEXEC) {
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char *tmp[BUFSIZ/sizeof(char *)];
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if (loadquery(L_GETMESSAGES, tmp, sizeof(tmp)) == -1)
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strcpy(errbuf, strerror(errno));
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else {
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char **p;
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for (p = tmp; *p; p++)
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caterr(*p);
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}
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} else
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strcat(errbuf, strerror(errno));
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return (VOID *) NULL;
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}
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mp->refCnt = 1;
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mp->next = modList;
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modList = mp;
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if (loadbind(0, mainModule, mp->entry) == -1) {
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dlclose(mp);
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errvalid++;
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strcpy(errbuf, "loadbind: ");
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strcat(errbuf, strerror(errno));
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return (VOID *) NULL;
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}
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/*
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* If the user wants global binding, loadbind against all other
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* loaded modules.
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*/
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if (mode & RTLD_GLOBAL) {
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register ModulePtr mp1;
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for (mp1 = mp->next; mp1; mp1 = mp1->next)
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if (loadbind(0, mp1->entry, mp->entry) == -1) {
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dlclose(mp);
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errvalid++;
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strcpy(errbuf, "loadbind: ");
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strcat(errbuf, strerror(errno));
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return (VOID *) NULL;
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}
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}
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if (readExports(mp) == -1) {
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dlclose(mp);
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return (VOID *) NULL;
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}
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/*
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* If there is a dl_info structure, call the init function.
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*/
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if (mp->info = (struct dl_info *)dlsym(mp, "dl_info")) {
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if (mp->info->init)
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(*mp->info->init)();
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} else
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errvalid = 0;
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/*
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* If the shared object was compiled using xlC we will need
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* to call static constructors (and later on dlclose destructors).
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*/
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if (mp->cdtors = (CdtorPtr)dlsym(mp, "__cdtors")) {
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while (mp->cdtors->init) {
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(*mp->cdtors->init)();
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mp->cdtors++;
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}
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} else
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errvalid = 0;
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return (VOID *) mp;
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}
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/*
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* Attempt to decipher an AIX loader error message and append it
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* to our static error message buffer.
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*/
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static void caterr(char *s)
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{
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register char *p = s;
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while (*p >= '0' && *p <= '9')
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p++;
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switch(atoi(s)) {
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case L_ERROR_TOOMANY:
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strcat(errbuf, "to many errors");
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break;
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case L_ERROR_NOLIB:
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strcat(errbuf, "can't load library");
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strcat(errbuf, p);
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break;
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case L_ERROR_UNDEF:
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strcat(errbuf, "can't find symbol");
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strcat(errbuf, p);
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break;
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case L_ERROR_RLDBAD:
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strcat(errbuf, "bad RLD");
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strcat(errbuf, p);
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break;
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case L_ERROR_FORMAT:
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strcat(errbuf, "bad exec format in");
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strcat(errbuf, p);
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break;
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case L_ERROR_ERRNO:
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strcat(errbuf, strerror(atoi(++p)));
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break;
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default:
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strcat(errbuf, s);
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break;
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}
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}
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VOID *dlsym(void *handle, const char *symbol)
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{
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register ModulePtr mp = (ModulePtr)handle;
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register ExportPtr ep;
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register int i;
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/*
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* Could speed up the search, but I assume that one assigns
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* the result to function pointers anyways.
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*/
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for (ep = mp->exports, i = mp->nExports; i; i--, ep++)
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if (strcmp(ep->name, symbol) == 0)
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return ep->addr;
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errvalid++;
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strcpy(errbuf, "dlsym: undefined symbol ");
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strcat(errbuf, symbol);
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return NULL;
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}
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char *dlerror(void)
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{
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if (errvalid) {
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errvalid = 0;
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return errbuf;
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}
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return NULL;
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}
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int dlclose(void *handle)
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{
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register ModulePtr mp = (ModulePtr)handle;
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int result;
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register ModulePtr mp1;
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if (--mp->refCnt > 0)
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return 0;
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if (mp->info && mp->info->fini)
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(*mp->info->fini)();
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if (mp->cdtors)
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while (mp->cdtors->term) {
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(*mp->cdtors->term)();
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mp->cdtors++;
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}
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result = unload(mp->entry);
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if (result == -1) {
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errvalid++;
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strcpy(errbuf, strerror(errno));
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}
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if (mp->exports) {
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register ExportPtr ep;
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register int i;
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for (ep = mp->exports, i = mp->nExports; i; i--, ep++)
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if (ep->name)
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free(ep->name);
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free(mp->exports);
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}
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if (mp == modList)
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modList = mp->next;
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else {
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for (mp1 = modList; mp1; mp1 = mp1->next)
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if (mp1->next == mp) {
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mp1->next = mp->next;
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break;
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}
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}
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free(mp->name);
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free(mp);
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return result;
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}
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static void terminate(void)
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{
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while (modList)
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dlclose(modList);
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}
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/*
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* Build the export table from the XCOFF .loader section.
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*/
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static int readExports(ModulePtr mp)
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{
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LDFILE *ldp = NULL;
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SCNHDR sh, shdata;
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LDHDR *lhp;
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char *ldbuf;
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LDSYM *ls;
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int i;
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ExportPtr ep;
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if ((ldp = ldopen(mp->name, ldp)) == NULL) {
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struct ld_info *lp;
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char *buf;
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int size = 4*1024;
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if (errno != ENOENT) {
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errvalid++;
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strcpy(errbuf, "readExports: ");
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strcat(errbuf, strerror(errno));
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return -1;
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}
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/*
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* The module might be loaded due to the LIBPATH
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* environment variable. Search for the loaded
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* module using L_GETINFO.
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*/
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if ((buf = malloc(size)) == NULL) {
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errvalid++;
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strcpy(errbuf, "readExports: ");
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strcat(errbuf, strerror(errno));
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return -1;
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}
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while ((i = loadquery(L_GETINFO, buf, size)) == -1 && errno == ENOMEM) {
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free(buf);
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size += 4*1024;
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if ((buf = malloc(size)) == NULL) {
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errvalid++;
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strcpy(errbuf, "readExports: ");
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strcat(errbuf, strerror(errno));
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return -1;
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}
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}
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if (i == -1) {
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errvalid++;
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strcpy(errbuf, "readExports: ");
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strcat(errbuf, strerror(errno));
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free(buf);
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return -1;
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}
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/*
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* Traverse the list of loaded modules. The entry point
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* returned by load() does actually point to the data
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* segment origin.
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*/
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lp = (struct ld_info *)buf;
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while (lp) {
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if (lp->ldinfo_dataorg == mp->entry) {
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ldp = ldopen(lp->ldinfo_filename, ldp);
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break;
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}
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if (lp->ldinfo_next == 0)
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lp = NULL;
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else
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lp = (struct ld_info *)((char *)lp + lp->ldinfo_next);
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}
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free(buf);
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if (!ldp) {
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errvalid++;
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strcpy(errbuf, "readExports: ");
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strcat(errbuf, strerror(errno));
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return -1;
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}
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}
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if (TYPE(ldp) != U802TOCMAGIC) {
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errvalid++;
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strcpy(errbuf, "readExports: bad magic");
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while(ldclose(ldp) == FAILURE)
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;
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return -1;
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}
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/*
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* Get the padding for the data section. This is needed for
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* AIX 4.1 compilers. This is used when building the final
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* function pointer to the exported symbol.
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*/
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if (ldnshread(ldp, _DATA, &shdata) != SUCCESS) {
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errvalid++;
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strcpy(errbuf, "readExports: cannot read data section header");
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while(ldclose(ldp) == FAILURE)
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;
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return -1;
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}
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if (ldnshread(ldp, _LOADER, &sh) != SUCCESS) {
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errvalid++;
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strcpy(errbuf, "readExports: cannot read loader section header");
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while(ldclose(ldp) == FAILURE)
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;
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return -1;
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}
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/*
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* We read the complete loader section in one chunk, this makes
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* finding long symbol names residing in the string table easier.
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*/
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if ((ldbuf = (char *)malloc(sh.s_size)) == NULL) {
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errvalid++;
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strcpy(errbuf, "readExports: ");
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strcat(errbuf, strerror(errno));
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while(ldclose(ldp) == FAILURE)
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;
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return -1;
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}
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if (FSEEK(ldp, sh.s_scnptr, BEGINNING) != OKFSEEK) {
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errvalid++;
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strcpy(errbuf, "readExports: cannot seek to loader section");
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free(ldbuf);
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while(ldclose(ldp) == FAILURE)
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;
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return -1;
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}
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if (FREAD(ldbuf, sh.s_size, 1, ldp) != 1) {
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errvalid++;
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strcpy(errbuf, "readExports: cannot read loader section");
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free(ldbuf);
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while(ldclose(ldp) == FAILURE)
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;
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return -1;
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}
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lhp = (LDHDR *)ldbuf;
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ls = (LDSYM *)(ldbuf+LDHDRSZ);
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/*
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* Count the number of exports to include in our export table.
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*/
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for (i = lhp->l_nsyms; i; i--, ls++) {
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if (!LDR_EXPORT(*ls))
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continue;
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mp->nExports++;
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}
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if ((mp->exports = (ExportPtr)calloc(mp->nExports, sizeof(*mp->exports))) == NULL) {
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errvalid++;
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strcpy(errbuf, "readExports: ");
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strcat(errbuf, strerror(errno));
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free(ldbuf);
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while(ldclose(ldp) == FAILURE)
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;
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return -1;
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}
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/*
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* Fill in the export table. All entries are relative to
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* the entry point we got from load.
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*/
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ep = mp->exports;
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ls = (LDSYM *)(ldbuf+LDHDRSZ);
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for (i = lhp->l_nsyms; i; i--, ls++) {
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char *symname;
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char tmpsym[SYMNMLEN+1];
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if (!LDR_EXPORT(*ls))
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continue;
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if (ls->l_zeroes == 0)
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symname = ls->l_offset+lhp->l_stoff+ldbuf;
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else {
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/*
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* The l_name member is not zero terminated, we
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* must copy the first SYMNMLEN chars and make
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* sure we have a zero byte at the end.
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*/
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strncpy(tmpsym, ls->l_name, SYMNMLEN);
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tmpsym[SYMNMLEN] = '\0';
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symname = tmpsym;
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}
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ep->name = malloc((unsigned) (strlen(symname) + 1));
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strcpy(ep->name, symname);
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ep->addr = (void *)((unsigned long)mp->entry +
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ls->l_value - shdata.s_vaddr);
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ep++;
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}
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free(ldbuf);
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while(ldclose(ldp) == FAILURE)
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;
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return 0;
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}
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/*
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* Find the main modules entry point. This is used as export pointer
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* for loadbind() to be able to resolve references to the main part.
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*/
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static void * findMain(void)
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{
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struct ld_info *lp;
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char *buf;
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int size = 4*1024;
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int i;
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void *ret;
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if ((buf = malloc(size)) == NULL) {
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errvalid++;
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strcpy(errbuf, "findMain: ");
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strcat(errbuf, strerror(errno));
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return NULL;
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}
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while ((i = loadquery(L_GETINFO, buf, size)) == -1 && errno == ENOMEM) {
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free(buf);
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size += 4*1024;
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if ((buf = malloc(size)) == NULL) {
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errvalid++;
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strcpy(errbuf, "findMain: ");
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strcat(errbuf, strerror(errno));
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return NULL;
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}
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}
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if (i == -1) {
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errvalid++;
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strcpy(errbuf, "findMain: ");
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strcat(errbuf, strerror(errno));
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free(buf);
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return NULL;
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}
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/*
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* The first entry is the main module. The entry point
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* returned by load() does actually point to the data
|
|
* segment origin.
|
|
*/
|
|
lp = (struct ld_info *)buf;
|
|
ret = lp->ldinfo_dataorg;
|
|
free(buf);
|
|
return ret;
|
|
}
|
|
|