+++ /dev/null
-$PostgreSQL: pgsql/src/backend/port/dynloader/README.dlfcn.aix,v 1.3 2008/03/21 13:23:28 momjian Exp $
-
-dynaloader
-==========
-
-Copyright (c) 1992,1993,1995, 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 no attempt is made to gain profit from it,
-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.
-
-libdl.a
--------
-
-This is an emulation library to emulate the SunOS/System V.4 functions
-to access the runtime linker. The functions are emulated by using the
-AIX load() function and by reading the .loader section of the loaded
-module to find the exports. The to be loaded module should be linked as
-follows (if using AIX 3):
-
- cc -o module.so -bM:SRE -bE:module.exp -e _nostart $(OBJS)
-
-For AIX 4:
-
- cc -o module.so -bM:SRE -bE:module.exp -bnoentry $(OBJS)
-
-The module export file contains the symbols to be exported. Because
-this library uses the loader section, the final module.so file can be
-stripped. C++ users should build their shared objects using the script
-makeC++SharedLib (part of the IBM C++ compiler), this will make sure
-that constructors and destructors for static and global objects will be
-called upon loading and unloading the module.
-
-Usage
------
-
-void *dlopen(const char *path, int mode);
-
-This routine loads the module pointed to by path and reads its export
-table. If the path does not contain a '/' character, dlopen will search
-for the module using the LIBPATH environment variable. It returns an
-opaque handle to the module or NULL on error. The mode parameter can be
-either RTLD_LAZY (for lazy function binding) or RTLD_NOW for immediate
-function binding. The AIX implementation currently behaves as RTLD_NOW
-even if RTLD_LAZY is specified. The flag RTLD_GLOBAL might be or'ed into the
-mode parameter to allow loaded modules to bind to global variables or
-functions in other loaded modules loaded by dlopen(). If RTLD_GLOBAL is
-not specified, only globals from the main part of the executable or
-shared libraries are used to look for undefined symbols in loaded
-modules.
-
-
-void *dlsym(void *handle, const char *symbol);
-
-This routine searches for the symbol in the module referred to by
-handle and returns its address. If the symbol could not be found, the
-function returns NULL. The return value must be casted to a proper
-function pointer before it can be used. SunOS/System V.4 allow handle
-to be a NULL pointer to refer to the module the call is made from, this
-is not implemented.
-
-int dlclose(void *handle);
-
-This routine unloads the module referred to by the handle and disposes
-of any local storage. this function returns -1 on failure.
-
-char *dlerror(void);
-
-This routine can be used to retrieve a text message describing the most
-recent error that occured on on of the above routines. This function
-returns NULL if there is not error information.
-
-Initialization and termination handlers
----------------------------------------
-
-The emulation provides for an initialization and a termination
-handler. The dlfcn.h file contains a structure declaration named
-dl_info with following members:
-
- void (*init)(void);
- void (*fini)(void);
-
-The init function is called upon first referencing the library. The
-fini function is called at dlclose() time or when the process exits.
-The module should declare a variable named dl_info that contains this
-structure which must be exported. These functions correspond to the
-documented _init() and _fini() functions of SunOS 4.x, but these are
-appearently not implemented in SunOS. When using SunOS 5.0, these
-correspond to #pragma init and #pragma fini respectively. At the same
-time any static or global C++ object's constructors or destructors will
-be called.
-
-Jens-Uwe Mager
-
-HELIOS Software GmbH
-Lavesstr. 80
-30159 Hannover
-Germany
-
-Phone: +49 511 36482-0
-FAX: +49 511 36482-69
-AppleLink: helios.de Attn: Jens-Uwe Mager
-Internet: jum@helios.de
-
-Revison History
----------------
-
-SCCS/s.dlfcn.h:
-
-D 1.4 95/04/25 09:36:52 jum 4 3 00018/00004/00028
-MRs:
-COMMENTS:
-added RTLD_GLOBAL, include and C++ guards
-
-D 1.3 92/12/27 20:58:32 jum 3 2 00001/00001/00031
-MRs:
-COMMENTS:
-we always have prototypes on RS/6000
-
-D 1.2 92/08/16 17:45:11 jum 2 1 00009/00000/00023
-MRs:
-COMMENTS:
-added dl_info structure to implement initialize and terminate functions
-
-D 1.1 92/08/02 18:08:45 jum 1 0 00023/00000/00000
-MRs:
-COMMENTS:
-Erstellungsdatum und -uhrzeit 92/08/02 18:08:45 von jum
-
-SCCS/s.dlfcn.c:
-
-D 1.7 95/08/14 19:08:38 jum 8 6 00026/00004/00502
-MRs:
-COMMENTS:
-Integrated the fixes from Kirk Benell (kirk@rsinc.com) to allow loading of
-shared objects generated under AIX 4. Fixed bug that symbols with exactly
-8 characters would use garbage characters from the following symbol value.
-
-D 1.6 95/04/25 09:38:03 jum 6 5 00046/00006/00460
-MRs:
-COMMENTS:
-added handling of C++ static constructors and destructors, added RTLD_GLOBAL to bind against other loaded modules
-
-D 1.5 93/02/14 20:14:17 jum 5 4 00002/00000/00464
-MRs:
-COMMENTS:
-added path to dlopen error message to make clear where there error occured.
-
-D 1.4 93/01/03 19:13:56 jum 4 3 00061/00005/00403
-MRs:
-COMMENTS:
-to allow calling symbols in the main module call load with L_NOAUTODEFER and
-do a loadbind later with the main module.
-
-D 1.3 92/12/27 20:59:55 jum 3 2 00066/00008/00342
-MRs:
-COMMENTS:
-added search by L_GETINFO if module got loaded by LIBPATH
-
-D 1.2 92/08/16 17:45:43 jum 2 1 00074/00006/00276
-MRs:
-COMMENTS:
-implemented initialize and terminate functions, added reference counting to avoid multiple loads of the same library
-
-D 1.1 92/08/02 18:08:45 jum 1 0 00282/00000/00000
-MRs:
-COMMENTS:
-Erstellungsdatum und -uhrzeit 92/08/02 18:08:45 von jum
-
/*
- * $PostgreSQL: pgsql/src/backend/port/dynloader/aix.c,v 1.20 2008/05/17 01:28:23 adunstan Exp $
+ * $PostgreSQL: pgsql/src/backend/port/dynloader/aix.c,v 1.21 2009/04/21 21:15:50 tgl Exp $
*
+ * Dummy file used for nothing at this point
*
- * @(#)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
+ * see aix.h
*/
-
-#include "postgres.h"
-
-#include "sys/ldr.h"
-#include <a.out.h>
-#include "ldfcn.h"
-
-#include "dynloader.h"
-
-#ifndef HAVE_DLOPEN
-
-/*
- * AIX 4.3 and up has dlopen() and friends in -ldl.
- * A la long, the homebrewn dl*() functions below should be obsolete.
- */
-
-/*
- * 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;
-
-extern char *strdup(const char *);
-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)
- {
- 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 mp;
- }
- if ((mp = (ModulePtr) calloc(1, sizeof(*mp))) == NULL)
- {
- errvalid++;
- strcpy(errbuf, "calloc: ");
- strcat(errbuf, strerror(errno));
- return NULL;
- }
- if ((mp->name = strdup(path)) == NULL)
- {
- errvalid++;
- strcpy(errbuf, "strdup: ");
- strcat(errbuf, strerror(errno));
- free(mp);
- return NULL;
- }
-
- /*
- * 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 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 NULL;
- }
-
- /*
- * If the user wants global binding, loadbind against all other loaded
- * modules.
- */
- if (mode & RTLD_GLOBAL)
- {
- 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 NULL;
- }
- }
- 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 mp;
-}
-
-/*
- * 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))
- {
- case L_ERROR_TOOMANY:
- strcat(errbuf, "to many errors");
- break;
- case L_ERROR_NOLIB:
- strcat(errbuf, "cannot load library");
- strcat(errbuf, p);
- break;
- case L_ERROR_UNDEF:
- strcat(errbuf, "cannot 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)
-{
- 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;
-
- 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 = strdup(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;
-}
-
-#endif /* HAVE_DLOPEN */
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