gri3-wm/libi3/get_exe_path.c

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#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <limits.h>
#include <stdlib.h>
#include "libi3.h"
/*
* This function returns the absolute path to the executable it is running in.
*
* The implementation follows http://stackoverflow.com/a/933996/712014
*
*/
const char *get_exe_path(const char *argv0) {
static char destpath[PATH_MAX];
char tmp[PATH_MAX];
#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
/* Linux and Debian/kFreeBSD provide /proc/self/exe */
#if defined(__linux__) || defined(__FreeBSD_kernel__)
const char *exepath = "/proc/self/exe";
#elif defined(__FreeBSD__)
const char *exepath = "/proc/curproc/file";
#endif
ssize_t linksize;
if ((linksize = readlink(exepath, destpath, sizeof(destpath))) != -1) {
/* readlink() does not NULL-terminate strings, so we have to. */
destpath[linksize] = '\0';
return destpath;
}
#endif
/* argv[0] is most likely a full path if it starts with a slash. */
if (argv0[0] == '/')
return argv0;
/* if argv[0] contains a /, prepend the working directory */
if (strchr(argv0, '/') != NULL &&
getcwd(tmp, sizeof(tmp)) != NULL) {
snprintf(destpath, sizeof(destpath), "%s/%s", tmp, argv0);
return destpath;
}
/* Fall back to searching $PATH (or _CS_PATH in absence of $PATH). */
char *path = getenv("PATH");
size_t pathlen;
if (path == NULL) {
/* _CS_PATH is typically something like "/bin:/usr/bin" */
pathlen = confstr(_CS_PATH, tmp, sizeof(tmp));
sasprintf(&path, ":%s", tmp);
} else {
pathlen = strlen(path);
path = strdup(path);
}
const char *component;
char *str = path;
while (1) {
if ((component = strtok(str, ":")) == NULL)
break;
str = NULL;
snprintf(destpath, sizeof(destpath), "%s/%s", component, argv0);
/* Of course this is not 100% equivalent to actually exec()ing the
* binary, but meh. */
if (access(destpath, X_OK) == 0) {
free(path);
return destpath;
}
}
free(path);
/* Last resort: maybe its in /usr/bin? */
return "/usr/bin/i3bar";
}