badvpn/misc/find_program.h
2014-11-12 21:52:49 +01:00

104 lines
3.3 KiB
C

/**
* @file find_program.h
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* Function that finds the absolute path of a program by checking a predefined
* list of directories.
*/
#ifndef BADVPN_FIND_PROGRAM_H
#define BADVPN_FIND_PROGRAM_H
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <misc/concat_strings.h>
#include <misc/debug.h>
#include <misc/balloc.h>
static char * badvpn_find_program (const char *name);
static char * badvpn_find_program (const char *name)
{
ASSERT(name)
char *path = getenv("PATH");
if (path) {
while (1) {
size_t i = 0;
while (path[i] != ':' && path[i] != '\0') {
i++;
}
char const *src = path;
size_t src_len = i;
if (src_len == 0) {
src = ".";
src_len = 1;
}
size_t name_len = strlen(name);
char *entry = BAllocSize(bsize_add(bsize_fromsize(src_len), bsize_add(bsize_fromsize(name_len), bsize_fromsize(2))));
if (!entry) {
goto fail;
}
memcpy(entry, src, src_len);
entry[src_len] = '/';
strcpy(entry + (src_len + 1), name);
if (access(entry, X_OK) == 0) {
return entry;
}
free(entry);
if (path[i] == '\0') {
break;
}
path += i + 1;
}
}
const char *dirs[] = {"/usr/sbin", "/usr/bin", "/sbin", "/bin", NULL};
for (size_t i = 0; dirs[i]; i++) {
char *try_path = concat_strings(3, dirs[i], "/", name);
if (!try_path) {
goto fail;
}
if (access(try_path, X_OK) == 0) {
return try_path;
}
free(try_path);
}
fail:
return NULL;
}
#endif