procps/pwdx.c

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/*
* Copyright 2004 Nicholas Miell
*
* This file may be used subject to the terms and conditions of the
* GNU Library General Public License Version 2 as published by the
* Free Software Foundation.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 Library General Public License for more
* details.
*/
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#include <errno.h>
#include <getopt.h>
#include <limits.h>
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
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#include <sys/types.h>
#include <unistd.h>
#include "proc/version.h"
static void __attribute__ ((__noreturn__)) usage(FILE * out)
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{
fprintf(out, "\nUsage:\n"
" %s [options] pid...\n", program_invocation_short_name);
fprintf(out,
"\nOptions:\n"
" -V, --version output version information and exit\n"
" -h, --help output help screen and exit\n\n");
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exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
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}
int main(int argc, char *argv[])
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{
char ch;
int retval = 0, i;
int alloclen = 128;
char *pathbuf;
static const struct option longopts[] = {
{"version", no_argument, 0, 'V'},
{"help", no_argument, 0, 'h'},
{NULL, 0, 0, 0}
};
while ((ch = getopt_long(argc, argv, "Vh", longopts, NULL)) != -1)
switch (ch) {
case 'V':
display_version();
return EXIT_SUCCESS;
case 'h':
usage(stdout);
default:
usage(stderr);
}
argc -= optind;
argv += optind;
if (argc == 0)
usage(stderr);
pathbuf = malloc(alloclen);
for (i = 0; i < argc; i++) {
char *s;
ssize_t len;
/* Constant 10 is the length of strings "/proc/" + "/cwd" + 1 */
char buf[10 + strlen(argv[i]) + 1];
/*
* At this point, all arguments are in the form
* /proc/NNNN or NNNN, so a simple check based on
* the first char is possible
*/
if (argv[i][0] != '/')
snprintf(buf, sizeof buf, "/proc/%s/cwd", argv[i]);
else
snprintf(buf, sizeof buf, "%s/cwd", argv[i]);
/*
* buf contains /proc/NNNN/cwd symlink name
* on entry, the target of that symlink on return
*/
while ((len = readlink(buf, pathbuf, alloclen)) == alloclen) {
alloclen *= 2;
pathbuf = realloc(pathbuf, alloclen);
}
if (len < 0) {
s = strerror(errno == ENOENT ? ESRCH : errno);
retval = 1;
} else {
pathbuf[len] = 0;
s = pathbuf;
}
printf("%s: %s\n", argv[i], s);
}
return retval;
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}