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      1 /*
      2  * Copyright (C) 2010 Cyril Hrubis chrubis (at) suse.cz
      3  *
      4  * This program is free software; you can redistribute it and/or modify it
      5  * under the terms of version 2 of the GNU General Public License as
      6  * published by the Free Software Foundation.
      7  *
      8  * This program is distributed in the hope that it would be useful, but
      9  * WITHOUT ANY WARRANTY; without even the implied warranty of
     10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
     11  *
     12  * Further, this software is distributed without any warranty that it is
     13  * free of the rightful claim of any third person regarding infringement
     14  * or the like.  Any license provided herein, whether implied or
     15  * otherwise, applies only to this software file.  Patent licenses, if
     16  * any, provided herein do not apply to combinations of this program with
     17  * other software, or any other product whatsoever.
     18  *
     19  * You should have received a copy of the GNU General Public License along
     20  * with this program; if not, write the Free Software Foundation, Inc.,
     21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
     22  */
     23 
     24  /*
     25   * Looks for binary prog_name in $PATH.
     26   *
     27   * If such file exists and if you are able at least to read it, zero is
     28   * returned and absolute path to the file is filled into buf. In case buf is
     29   * too short to hold the absolute path + prog_name for the file we are looking
     30   * for -1 is returned as well as when there is no such file in all paths in
     31   * $PATH.
     32   */
     33 
     34 #include "test.h"
     35 
     36 #include <stdio.h>
     37 #include <string.h>
     38 #include <stdlib.h>
     39 #include <unistd.h>
     40 #include <sys/types.h>
     41 #include <sys/stat.h>
     42 
     43 #ifndef MIN
     44 #define MIN(a, b) ((a)<(b)?(a):(b))
     45 #endif
     46 
     47 static int file_exist(const char *path)
     48 {
     49 	struct stat st;
     50 
     51 	if (!access(path, R_OK) && !stat(path, &st) && S_ISREG(st.st_mode))
     52 		return 1;
     53 
     54 	return 0;
     55 }
     56 
     57 int tst_get_path(const char *prog_name, char *buf, size_t buf_len)
     58 {
     59 	const char *path = (const char *)getenv("PATH");
     60 	const char *start = path;
     61 	const char *end;
     62 	size_t size, ret;
     63 
     64 	if (path == NULL)
     65 		return -1;
     66 
     67 	do {
     68 		end = strchr(start, ':');
     69 
     70 		if (end != NULL)
     71 			snprintf(buf, MIN(buf_len, (size_t) (end - start + 1)),
     72 				 "%s", start);
     73 		else
     74 			snprintf(buf, buf_len, "%s", start);
     75 
     76 		size = strlen(buf);
     77 
     78 		/*
     79 		 * "::" inside $PATH, $PATH ending with ':' or $PATH starting
     80 		 * with ':' should be expanded into current working directory.
     81 		 */
     82 		if (size == 0) {
     83 			snprintf(buf, buf_len, ".");
     84 			size = strlen(buf);
     85 		}
     86 
     87 		/*
     88 		 * If there is no '/' ad the end of path from $PATH add it.
     89 		 */
     90 		if (buf[size - 1] != '/')
     91 			ret =
     92 			    snprintf(buf + size, buf_len - size, "/%s",
     93 				     prog_name);
     94 		else
     95 			ret =
     96 			    snprintf(buf + size, buf_len - size, "%s",
     97 				     prog_name);
     98 
     99 		if (buf_len - size > ret && file_exist(buf))
    100 			return 0;
    101 
    102 		start = end + 1;
    103 
    104 	} while (end != NULL);
    105 
    106 	return -1;
    107 }
    108