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#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <sys/file.h>
#include "log.h"
#include "xmalloc.h"
static const char *default_cache_dir = ".cache/";
static const char *lock_filename = "tofi.lock";
[[nodiscard("memory leaked")]]
static char *get_lock_path() {
char *lock_name = NULL;
const char *runtime_path = getenv("XDG_RUNTIME_DIR");
if (runtime_path == NULL) {
runtime_path = getenv("XDG_CACHE_HOME");
}
if (runtime_path == NULL) {
const char *home = getenv("HOME");
if (home == NULL) {
log_error("Couldn't retrieve HOME from environment.\n");
return NULL;
}
size_t len = strlen(home) + 1
+ strlen(default_cache_dir) + 1
+ strlen(lock_filename) + 1;
lock_name = xmalloc(len);
snprintf(
lock_name,
len,
"%s/%s/%s",
home,
default_cache_dir,
lock_filename);
} else {
size_t len = strlen(runtime_path) + 1
+ strlen(lock_filename) + 1;
lock_name = xmalloc(len);
snprintf(
lock_name,
len,
"%s/%s",
runtime_path,
lock_filename);
}
return lock_name;
}
bool lock_check(void)
{
bool ret = false;
char *filename = get_lock_path();
errno = 0;
int fd = open(filename, O_RDONLY | O_CREAT, S_IRUSR | S_IWUSR);
if (fd == -1) {
log_error("Failed to open lock file %s: %s.\n", filename, strerror(errno));
} else if (flock(fd, LOCK_EX | LOCK_NB) == -1) {
if (errno == EWOULDBLOCK) {
/*
* We can't lock the file because another tofi process
* already has.
*/
ret = true;
}
}
free(filename);
return ret;
}
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