Blame src/core/lt_path.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 <limits.h>
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#include <dlfcn.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.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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#include "sltdl_module.h"
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#ifdef  O_EXEC
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#define SLTDL_MODULE_OPEN_OPTIONS (O_CLOEXEC|O_EXEC)
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#else
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#define SLTDL_MODULE_OPEN_OPTIONS (O_CLOEXEC)
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#endif
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static int     lt_status;
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static off_t   lt_plen;
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static off_t   lt_plocs;
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static char *  lt_upath;
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static char *  lt_vpath;
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static char ** lt_vmark;
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static char ** lt_pathv;
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static struct lt_modctx * lt_modv_head;
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static struct lt_modctx * lt_modv_tail;
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static struct lt_modctx * lt_modv_next;
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static struct lt_modctx * lt_modv_cap;
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static int lt_setstatus(int ret, int status)
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{
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	lt_status = status;
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	return ret;
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}
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const char * lt_dlgetsearchpath(void)
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{
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	return lt_upath;
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}
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static int lt_dlsetsearchpath_locked(const char * path)
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{
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	const char *    ch;
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	char *          uch;
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	char *          vch;
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	char **         pathv;
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	off_t           elements;
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	if (path[0] != '/')
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		return lt_setstatus(1,SLTDL_PATH_INVALID_FIRST_CHAR);
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	elements = 1;
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	for (ch=&path[1]; *ch; ch++) {
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		if (*ch == ':') {
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			if (ch[1] != '/')
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				return lt_setstatus(1,SLTDL_PATH_INVALID_FIRST_CHAR);
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			elements++;
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		}
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	}
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	if (++elements > lt_plocs) {
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		if (lt_pathv) {
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			free(lt_pathv);
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			lt_pathv = 0;
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		}
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		lt_plocs  = elements;
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		lt_plocs += 0x3f;
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		lt_plocs |= 0x3f;
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		lt_plocs ^= 0x3f;
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		if (!(lt_pathv = calloc(lt_plocs,sizeof(char *))))
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			return lt_setstatus(1,SLTDL_SYSTEM_ERROR);
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	}
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	if ((ch - path) > lt_plen) {
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		if (lt_upath) {
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			free(lt_upath);
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			lt_upath = 0;
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		}
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		lt_plen = ((ch - path + 1) <= 0x800)
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			? 0x800 : ch - path + 1;
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		lt_plen += 0x7ff;
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		lt_plen |= 0x7ff;
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		lt_plen ^= 0x7ff;
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		if (!(lt_upath = calloc(2*lt_plen,1)))
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			return lt_setstatus(1,SLTDL_SYSTEM_ERROR);
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		lt_vpath = &lt_upath[lt_plen];
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	}
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	pathv    = lt_pathv;
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	*pathv++ = lt_vpath;
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	for (ch=path, uch=lt_upath, vch=lt_vpath; *ch; ch++) {
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		if (*ch == ':') {
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			*uch++ = ch[0];
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			*uch++ = ch[1];
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			*vch++ = 0;
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			*pathv = vch;
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			*vch++ = ch[1];
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			ch++;
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			pathv++;
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		} else {
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			*uch++ = *ch;
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			*vch++ = *ch;
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		}
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	}
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	lt_vmark = pathv;
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	return lt_setstatus(0,SLTDL_OK);
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}
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int lt_dlsetsearchpath(const char * path)
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{
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	int ret;
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	lt_slock();
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	ret = lt_dlsetsearchpath_locked(path);
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	return lt_sunlock(ret,lt_status);
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}
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static int lt_dladdsearchdir_locked(const char * path)
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{
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	int          ret;
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	const char * ch;
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	char *       buf;
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	off_t        alen;
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	off_t        plen;
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	if (path[0] != '/')
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		return lt_setstatus(1,SLTDL_PATH_INVALID_FIRST_CHAR);
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	for (ch=path; *ch; ch++)
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		if (*ch == ':')
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			return lt_setstatus(1,SLTDL_PATH_INVALID_SEPARATTOR_CHAR);
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	alen = strlen(path);
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	plen = strlen(lt_upath);
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	/* no allocation needed? */
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	if (!lt_pathv[lt_plocs - 2] && ((plen + 1 + alen + 1) <= lt_plen)) {
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		lt_upath[plen] = ':';
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		lt_vpath[plen] = 0;
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		plen++;
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		strcpy(&lt_upath[plen],path);
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		strcpy(&lt_vpath[plen],path);
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		*lt_vmark++ = &lt_vpath[plen];
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		return lt_setstatus(0,SLTDL_OK);
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	}
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	/* (allocation needed) */
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	if (!(buf = malloc(plen + 1 + alen + 1)))
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		return lt_setstatus(1,SLTDL_SYSTEM_ERROR);
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	sprintf(buf,"%s:%s",lt_upath,path);
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	ret = lt_dlsetsearchpath_locked(buf);
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	free(buf);
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	return ret;
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}
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int lt_dladdsearchdir(const char * path)
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{
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	int ret;
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	lt_slock();
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	ret = lt_dladdsearchdir_locked(path);
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	return lt_sunlock(ret,lt_status);
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}
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int lt_dlinsertsearchdir(const char * mark, const char * path)
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{
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	int          ret;
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	const char * ch;
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	char *       buf;
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	char *       dst;
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	off_t        alen;
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	off_t        plen;
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	off_t        slen;
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	off_t        offset;
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	char **      pathv;
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	if (!mark)
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		return lt_dladdsearchdir(path);
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	lt_slock();
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	if (path[0] != '/')
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		return lt_sunlock(1,SLTDL_PATH_INVALID_FIRST_CHAR);
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	for (ch=path; *ch; ch++)
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		if (*ch == ':')
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			return lt_sunlock(1,SLTDL_PATH_INVALID_SEPARATTOR_CHAR);
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	alen = strlen(path);
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	plen = strlen(lt_upath);
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	if ((mark < lt_upath) || (mark >= &lt_upath[plen]))
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		return lt_sunlock(1,SLTDL_PATH_INVALID_MARK);
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	if ((mark > lt_upath) && (mark[-1] != ':'))
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		return lt_sunlock(1,SLTDL_PATH_INVALID_MARK);
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	mark = &lt_vpath[mark - lt_upath];
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	/* no allocation needed? */
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	if (!lt_pathv[lt_plocs - 2] && ((plen + 1 + alen + 1) <= lt_plen)) {
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		for (pathv=lt_vmark; pathv>=lt_pathv; pathv--) {
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			slen    = strlen(pathv[-1]);
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			offset  = pathv[-1] - lt_vpath;
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			offset += alen + 1;
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			memcpy(&lt_upath[offset],pathv[-1],slen);
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			memcpy(&lt_vpath[offset],&lt_upath[offset],slen);
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			if (pathv < lt_vmark)
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				lt_upath[offset + slen] = ':';
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			pathv[0] = pathv[-1] + alen + 1;
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			if (pathv[-1] == mark) {
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				offset = mark - lt_vpath;
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				strcpy(&lt_vpath[offset],path);
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				memcpy(&lt_upath[offset],path,alen);
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				lt_upath[offset+alen] = ':';
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				lt_vmark++;
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				return lt_sunlock(0,SLTDL_OK);
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			}
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		}
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	}
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	/* (allocation needed) */
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	if (!(buf = malloc(plen + 1 + alen + 1)))
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		return lt_sunlock(1,SLTDL_SYSTEM_ERROR);
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	for (dst=buf, pathv=lt_pathv; *pathv; pathv++) {
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		if (*pathv == mark)
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			dst += sprintf(dst,"%s:",path);
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		if (pathv[1])
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			dst += sprintf(dst,"%s:",*pathv);
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		else
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			dst += sprintf(dst,"%s",*pathv);
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	}
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	ret = lt_dlsetsearchpath_locked(buf);
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	free(buf);
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	return lt_sunlock(ret,lt_status);
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}
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static int lt_dlpathopen_locked(
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	const char *  module,
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	const char ** extv,
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	char **       mpath)
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{
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	int           fdat;
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	int           fdmod;
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	char **       ppath;
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	const char ** pext;
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	size_t        plen;
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	size_t        mlen;
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	size_t        elen;
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	char          path[1024];
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	if ((mlen = strlen(module)) >= sizeof(path))
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		return lt_setstatus(-1,SLTDL_PATH_INVALID_LEN);
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	memcpy(path,module,mlen);
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	for (ppath=lt_pathv; *ppath; ppath++) {
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		fdat = open(*ppath,O_RDONLY|O_DIRECTORY|O_CLOEXEC,0);
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		if (fdat >= 0) {
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			for (pext=extv; *pext; pext++) {
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				if (mlen + (elen = strlen(*pext)) >= (sizeof(path))) {
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					close(fdat);
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					return lt_setstatus(-1,SLTDL_PATH_INVALID_LEN);
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				}
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				memcpy(&path[mlen],*pext,elen);
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				path[mlen+elen] = 0;
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				fdmod = openat(fdat,path,SLTDL_MODULE_OPEN_OPTIONS,0);
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				if (fdmod >= 0) {
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					if (mpath) {
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						plen  = strlen(*ppath);
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						plen += mlen + 1 + elen + 1;
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						if (!(*mpath = malloc(plen))) {
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							close(fdat);
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							close(fdmod);
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							return lt_setstatus(-1,SLTDL_SYSTEM_ERROR);
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						}
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						sprintf(*mpath,"%s/%s",*ppath,path);
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					}
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					close(fdat);
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					return lt_setstatus(fdmod,SLTDL_OK);
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				}
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			}
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			close(fdat);
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		}
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	}
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	return lt_setstatus(-1,SLTDL_PATH_NO_ENTRY);
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}
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int lt_dlpathopen(const char * module, const char ** extv)
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{
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	int ret;
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	lt_slock();
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	ret = lt_dlpathopen_locked(module,extv,0);
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	return lt_sunlock(ret,lt_status);
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}
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static struct lt_modctx * lt_dlopen_locked(
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	const char *  module,
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	const char ** extv,
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	int           mode)
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{
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	int                 fdmod;
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	char *              mpath;
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	void *              maddr;
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	struct lt_modctx *  modctx;
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	struct lt_modctx *  modctx_buf;
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	/* path open */
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	if ((fdmod = lt_dlpathopen_locked(module,extv,&mpath)) < 0)
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		return 0;
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	close(fdmod);
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	/* entry alloc */
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	if (lt_modv_next == lt_modv_cap) {
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		if (!(modctx_buf = calloc(64,sizeof(*modctx)))) {
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			free(mpath);
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			lt_setstatus(0,SLTDL_SYSTEM_ERROR);
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			return 0;
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		}
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		lt_modv_next = modctx_buf;
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		lt_modv_cap  = &lt_modv_next[64];
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	}
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	/* dlopen */
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	if (!(maddr = dlopen(mpath,mode))) {
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		free(mpath);
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		lt_setstatus(0,SLTDL_DLFCN_ERROR);
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		return 0;
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	}
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	/* already dlopen'ed? */
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	for (modctx=lt_modv_head; modctx; modctx=modctx->mnext) {
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		if (!strcmp(modctx->mpath,mpath)) {
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			free(mpath);
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			modctx->mrefs++;
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			return modctx;
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		}
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	}
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	/* module entry */
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	modctx        = lt_modv_next;
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	modctx->maddr = maddr;
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	modctx->mpath = mpath;
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	modctx->mrefs = 1;
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	lt_modv_next++;
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	/* add to list */
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	if (lt_modv_tail) {
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		lt_modv_tail->mnext = modctx;
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		lt_modv_tail        = modctx;
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	} else {
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		lt_modv_head        = modctx;
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		lt_modv_tail        = modctx;
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	}
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	/* all done */
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	return modctx;
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}
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struct lt_modctx * lt_dlopen(const char * module)
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{
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	struct lt_modctx * modctx;
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	const char *       extv[2] = {"",0};
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	lt_slock();
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	modctx = lt_dlopen_locked(module,extv,RTLD_NOW);
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	lt_sunlock(0,lt_status);
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	return modctx;
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}
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struct lt_modctx * lt_dlopenext(const char * module)
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{
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	struct lt_modctx * modctx;
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	const char *       extv[3] = {"",OS_LIB_SUFFIX,0};
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	lt_slock();
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	modctx = lt_dlopen_locked(module,extv,RTLD_NOW);
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	lt_sunlock(0,lt_status);
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	return modctx;
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}
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struct lt_modctx * lt_dlopenadvise(const char * module, struct lt_modctl * modctl)
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{
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	(void)modctl;
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	return lt_dlopenext(module);
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}
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void * lt_dlsym(struct lt_modctx * modctx, const char * symname)
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{
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	return dlsym(modctx->maddr,symname);
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}
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int lt_dlclose(struct lt_modctx * modctx)
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{
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	struct lt_modctx * pmod;
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	lt_slock();
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	for (pmod=lt_modv_head; pmod ; pmod=pmod->mnext) {
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		if (pmod == modctx) {
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			if (pmod->mrefs) {
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				pmod->mrefs--;
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				return lt_sunlock(0,SLTDL_OK);
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			}
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			return lt_sunlock(-1,SLTDL_MODULE_REF_COUNT);
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		}
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	}
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	return lt_sunlock(-1,SLTDL_MODULE_PTR_INVALID);
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}