# HG changeset patch
# User jwe
# Date 828913834 0
# Node ID 7e430470e098cb55c804a9571caba26c90ca46e5
# Parent  59754656026fa75a4085fa18e9a61a24a0c8d06f
[project @ 1996-04-07 21:50:34 by jwe]
Initial revision

diff -r 59754656026f -r 7e430470e098 dlfcn/dlfcn.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dlfcn/dlfcn.c	Sun Apr 07 21:50:34 1996 +0000
@@ -0,0 +1,533 @@
+/*
+ * @(#)dlfcn.c	1.10 revision of 96/02/15  17:42:44
+ * This is an unpublished work copyright (c) 1992 HELIOS Software GmbH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"
+
+/*
+ * 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")) {
+		CdtorPtr cp = mp->cdtors;
+		while (cp->init || cp->term) {
+			if (cp->init && cp->init != (void (*)(void))0xffffffff)
+				(*cp->init)();
+			cp++;
+		}
+	} 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) {
+		CdtorPtr cp = mp->cdtors;
+		while (cp->init || cp->term) {
+			if (cp->term && cp->init != (void (*)(void))0xffffffff)
+				(*cp->term)();
+			cp++;
+		}
+	}
+	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 = 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;
+}
diff -r 59754656026f -r 7e430470e098 dlfcn/dlfcn.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dlfcn/dlfcn.h	Sun Apr 07 21:50:34 1996 +0000
@@ -0,0 +1,46 @@
+/*
+ * @(#)dlfcn.h	1.4 revision of 95/04/25  09:36:52
+ * This is an unpublished work copyright (c) 1992 HELIOS Software GmbH
+ * 30159 Hannover, Germany
+ */
+
+#ifndef __dlfcn_h__
+#define __dlfcn_h__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Mode flags for the dlopen routine.
+ */
+#define RTLD_LAZY	1	/* lazy function call binding */
+#define RTLD_NOW	2	/* immediate function call binding */
+#define RTLD_GLOBAL	0x100	/* allow symbols to be global */
+
+/*
+ * To be able to intialize, a library may provide a dl_info structure
+ * that contains functions to be called to initialize and terminate.
+ */
+struct dl_info {
+	void (*init)(void);
+	void (*fini)(void);
+};
+
+#if __STDC__ || defined(_IBMR2)
+void *dlopen(const char *path, int mode);
+void *dlsym(void *handle, const char *symbol);
+char *dlerror(void);
+int dlclose(void *handle);
+#else
+void *dlopen();
+void *dlsym();
+char *dlerror();
+int dlclose();
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __dlfcn_h__ */