1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
|
/* See LICENSE for licence details. */
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/stat.h>
#include <stdlib.h>
int main(int argc, char **argv){
size_t pathlen, argvlen;
char *path;
if(argc != 2){
fprintf(stderr, "Please supply one argument: the lock directory.\n");
return EXIT_FAILURE;
}
if(access(argv[1], F_OK)){
/* create lock */
if(mkdir(argv[1], S_IRUSR | S_IXUSR)){
fprintf(stderr, "Failed to create lock %s.\n", argv[1]);
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
/* prepare path */
argvlen = strlen(argv[1]);
pathlen = argvlen + sizeof("/..") + 1;
path = malloc(pathlen);
if(path == NULL) {
fprintf(stderr, "malloc() failed\n");
return EXIT_FAILURE;
}
memcpy(path, argv[1], argvlen);
memcpy(path + argvlen, "/..\0", sizeof("/..") + 1);
if(access(path, F_OK)){
/* invalid lock */
fprintf(stderr, "%s is not a lock directory.\n", argv[1]);
free(path);
return EXIT_FAILURE;
}
/* lock exists */
for(; !access(path, F_OK) ;){
sleep(1);
}
free(path);
return EXIT_SUCCESS;
}
|
