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These files will get link'd to 'dynloader.[ch]', from configure, which

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will then get link'd into SUBSYS.o
This commit is contained in:
Marc G. Fournier
1997-12-19 22:58:27 +00:00
parent 56a7d9fac2
commit 153558dff8
4 changed files with 933 additions and 0 deletions
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603
src/backend/port/dynloader/aix.c Normal file
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@@ -0,0 +1,603 @@
/*
* @(#)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* This is an unpublished work copyright (c) 1992 HELIOS Software GmbH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 "dlfcn.h"
#include "c.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;
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)
{
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 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)
{
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 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)
{
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+1);
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;
}