Blame src/core/lt_core.c

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/*******************************************************************/
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/*  sltdl: a surrogate ltdl implementation                         */
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/*  Copyright (C) 2019 Z. Gilboa                                   */
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/*  Released under the Standard MIT License; see COPYING.SLTDL.    */
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/*******************************************************************/
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#include <dlfcn.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <pthread.h>
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#include <sltdl/sltdl.h>
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#include "sltdl_core.h"
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static const char * lt_dlerror_desc[] = {
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	[SLTDL_OK]                              = 0,
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	[SLTDL_SYSTEM_ERROR]                    = 0,
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	[SLTDL_DLFCN_ERROR]                     = 0,
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	[SLTDL_SLTDL_ERROR]                     = "sltdl internal error",
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	[SLTDL_DLEXIT_REF_COUNT]                = "lt_dlexit() reference count already zero",
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	[SLTDL_MODULE_REF_COUNT]                = "module reference count already zero",
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	[SLTDL_MODULE_PTR_INVALID]              = "module handle invalid",
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	[SLTDL_PATH_INVALID_FIRST_CHAR]         = "invalid path (does not begin with a forward slash)",
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	[SLTDL_PATH_INVALID_SEPARATTOR_CHAR]    = "invalid path (separator character is not a colon)",
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	[SLTDL_PATH_INVALID_MARK]               = "invalid path (mark not within range)",
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	[SLTDL_PATH_INVALID_LEN]                = "invalid path (string too long)",
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	[SLTDL_PATH_NO_ENTRY]                   = "invalid path (not found)",
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};
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static int             lt_refs  = 0;
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static int             lt_error = 0;
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static int             lt_errno = 0;
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static char *          lt_dlerr = 0;
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static pthread_mutex_t lt_lock  = PTHREAD_MUTEX_INITIALIZER;
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int lt_dlinit(void)
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{
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	if (pthread_mutex_lock(&lt_lock))
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		return 1;
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	lt_refs++;
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	pthread_mutex_unlock(&lt_lock);
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	return 0;
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}
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int lt_dlexit(void)
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{
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	if (pthread_mutex_lock(&lt_lock))
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		return 1;
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	if (!lt_refs) {
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		lt_error = SLTDL_DLEXIT_REF_COUNT;
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		pthread_mutex_unlock(&lt_lock);
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		return 1;
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	}
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	lt_refs--;
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	pthread_mutex_unlock(&lt_lock);
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	return 0;
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}
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void lt_slock(void)
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{
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	int locked;
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	do {
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		locked = pthread_mutex_lock(&lt_lock);
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	} while (locked);
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}
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int lt_sunlock(int ret, int error)
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{
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	if (error ==  0) {
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		pthread_mutex_unlock(&lt_lock);
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		return 0;
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	}
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	if ((error < 0) || (error >= SLTDL_ERROR_CAP)) {
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		error = SLTDL_SLTDL_ERROR;
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	} else if (error == SLTDL_SYSTEM_ERROR) {
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		lt_errno = errno;
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	} else if (error == SLTDL_DLFCN_ERROR) {
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		if (lt_dlerr)
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			free(lt_dlerr);
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		lt_dlerr = strdup(dlerror());
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	}
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	lt_error = error;
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	pthread_mutex_unlock(&lt_lock);
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	return ret;
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}
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const char * lt_dlerror(void)
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{
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	const char * errdesc;
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	lt_slock();
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	switch (lt_error) {
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		case SLTDL_OK:
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			errdesc = 0;
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			break;
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		case SLTDL_SYSTEM_ERROR:
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			errdesc = strerror(lt_errno);
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			break;
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		case SLTDL_DLFCN_ERROR:
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			errdesc = lt_dlerr;
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			break;
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		default:
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			errdesc = lt_dlerror_desc[lt_error];
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			break;
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	}
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	lt_error = 0;
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	lt_sunlock(0,0);
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	return errdesc;
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}