631 lines
13 KiB
C
631 lines
13 KiB
C
/*
|
||
* 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* This is an unpublished work copyright (c) 1992 HELIOS Software GmbH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)
|
||
{
|
||
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: ");
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||
strcat(errbuf, strerror(errno));
|
||
return NULL;
|
||
}
|
||
|
||
mp->name = malloc(strlen(path) + 1);
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strcpy(mp->name, path);
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||
|
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/*
|
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* load should be declared load(const char *...). Thus we cast the path to
|
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* a normal char *. Ugly.
|
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*/
|
||
|
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mp->entry = (void *) load((char *)path, L_NOAUTODEFER, NULL);
|
||
if (mp->entry == NULL) {
|
||
free(mp->name);
|
||
free(mp);
|
||
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 can be further
|
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* described by querying the loader about the last error.
|
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*/
|
||
|
||
if (errno == ENOEXEC) {
|
||
char *tmp[BUFSIZ/sizeof(char *)], **p;
|
||
|
||
if (loadquery(L_GETMESSAGES, tmp, sizeof(tmp)) == -1) {
|
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strcpy(errbuf, strerror(errno));
|
||
} else {
|
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for (p=tmp ; *p ; p++) {
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||
caterr(*p);
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}
|
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}
|
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} else {
|
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strcat(errbuf, strerror(errno));
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}
|
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return 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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loadbindFailure:
|
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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 NULL;
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||
}
|
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|
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/*
|
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* If the user wants global binding, loadbind against all other loaded
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* modules.
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*/
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|
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if (mode & RTLD_GLOBAL) {
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ModulePtr mp1;
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|
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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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||
goto loadbindFailure;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (readExports(mp) == -1) {
|
||
dlclose(mp);
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return 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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}
|
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} else {
|
||
errvalid = 0;
|
||
}
|
||
|
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/*
|
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* If the shared object was compiled using xlC we will need to call static
|
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* constructors (and later on dlclose destructors).
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*/
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||
|
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if (mp->cdtors = (CdtorPtr) dlsym(mp, "__cdtors")) {
|
||
while (mp->cdtors->init) {
|
||
mp->cdtors->init();
|
||
mp->cdtors++;
|
||
}
|
||
} else {
|
||
errvalid = 0;
|
||
}
|
||
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||
return (void *) mp;
|
||
}
|
||
|
||
/*
|
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* Attempt to decipher an AIX loader error message and append it to our static
|
||
* error message buffer.
|
||
*/
|
||
|
||
static void
|
||
caterr(
|
||
char *s)
|
||
{
|
||
char *p = s;
|
||
|
||
while (*p >= '0' && *p <= '9') {
|
||
p++;
|
||
}
|
||
switch (atoi(s)) { /* INTL: "C", UTF safe. */
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||
case L_ERROR_TOOMANY:
|
||
strcat(errbuf, "to many errors");
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||
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");
|
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strcat(errbuf, p);
|
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break;
|
||
case L_ERROR_RLDBAD:
|
||
strcat(errbuf, "bad RLD");
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||
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)
|
||
{
|
||
ModulePtr mp = (ModulePtr)handle;
|
||
ExportPtr ep;
|
||
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)
|
||
{
|
||
ModulePtr mp = (ModulePtr)handle;
|
||
int result;
|
||
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) {
|
||
ExportPtr ep;
|
||
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(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:
|
||
*/
|