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/*
Copyright (C) 2010, 2011
Rocky Bernstein <rocky@gnu.org>
Diego 'Flameeyes' Pettenò
Thomas Schmitt
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
POSIX realpath if that's around, and something like it if not.
To compile as a standalone program:
gcc -Wall -g -I../.. -DHAVE_CONFIG_H -DSTANDALONE -o realpath realpath.c
*/
/*
Make sure we handle:
- resolve relative links like /dev/cdrom -> sr2
- abort on cyclic linking like /dev/cdrom -> /dev/cdrom
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
# define __CDIO_CONFIG_H__ 1
#endif
#include <ctype.h>
#ifdef HAVE_STDLIB_H
# include <stdlib.h>
#endif
#ifdef HAVE_STDIO_H
# include <stdio.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_UNISTD_H /* readlink */
# include <unistd.h>
#endif
#ifdef HAVE_INTTYPES_H
# include "inttypes.h"
#endif
#ifdef HAVE_LIMITS_H
# include <limits.h>
#endif
#ifndef PATH_MAX
#define PATH_MAX 4096
#endif
#include <cdio/util.h>
/*! cdio_realpath() same as POSIX.1-2001 realpath if that's
around. If not we do poor-man's simulation of that behavior. */
char *cdio_realpath (const char *psz_src_path, char *psz_resolved_path) {
#ifdef HAVE_REALPATH
psz_resolved_path = realpath(psz_src_path, psz_resolved_path);
#elif defined(HAVE_READLINK)
char tmp_src[PATH_MAX+1];
char tmp_dst[PATH_MAX+1];
char *p_adr;
int i, len;
const int loop_limit = 100;
strcpy(tmp_src, psz_src_path);
/* FIXME:
remove loop and change with stat before and after readlink
which looks direct symlink. Rely on errno to figure out other
non-existent or looped symlinks.
*/
for(i = 0; i < loop_limit; i++) {
len = readlink(tmp_src, tmp_dst, PATH_MAX);
if (-1 == len) {
/* Right now we expect a "not symlink" error. However after
we put in the stat() suggested above, there won't be a symlink
error and we should start reporting what the failure is.
*/
break;
} else {
tmp_dst[len] = '\0';
if (tmp_dst[0] != '/') {
/* Take care of relative link like /dev/cdrom -> sr2 */
p_adr = strrchr(tmp_src, '/');
if (p_adr != NULL) {
strncpy(p_adr + 1, tmp_dst, PATH_MAX - (p_adr + 1 - tmp_src));
} else {
strncpy(tmp_src, tmp_dst, PATH_MAX);
}
} else {
strncpy(tmp_src, tmp_dst, PATH_MAX);
}
tmp_src[PATH_MAX - 1] = 0; /* strncpy() does not always set a 0 */
}
}
strncpy(psz_resolved_path, tmp_src, PATH_MAX);
#else
strncpy(psz_resolved_path, psz_src_path, PATH_MAX);
#endif
return psz_resolved_path;
}
#ifdef STANDALONE
int main(int argc, char **argv)
{
int i;
char dest[PATH_MAX];
if (argc < 2) {
fprintf(stderr, "Usage: %s path [path ...]\n", argv[0]);
fprintf(stderr,
" Resolve symbolic links\n");
exit(1);
}
for (i= 1; i < argc; i++) {
dest[0] = 0;
cdio_realpath (argv[i], dest);
printf("%s -> %s\n", argv[i], dest);
}
exit(0);
}
#endif
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