touch.c revision 795165bc1512faa121083c6bf3ce6f6d83ce59e6 
1#include <stdio.h>
2#include <string.h>
3#include <sys/types.h>
4#include <fcntl.h>
5#include <sys/stat.h>
6#include <stdlib.h>
7#include <fcntl.h>
8
9static void usage(void)
10{
11        fprintf(stderr, "touch: usage: touch [-alm] [-t time_t] <file>\n");
12        exit(1);
13}
14
15int touch_main(int argc, char *argv[])
16{
17        int i, fd, aflag = 0, mflag = 0, debug = 0, flags = 0;
18        struct timespec specified_time, times[2];
19        char *file = 0;
20
21        specified_time.tv_nsec = UTIME_NOW;
22
23        for (i = 1; i < argc; i++) {
24            if (argv[i][0] == '-') {
25                /* an option */
26                const char *arg = argv[i]+1;
27                while (arg[0]) {
28                    switch (arg[0]) {
29                    case 'a': aflag = 1; break;
30                    case 'm': mflag = 1; break;
31                    case 't':
32                        if ((i+1) >= argc)
33                            usage();
34                        specified_time.tv_sec = atol(argv[++i]);
35                        if (specified_time.tv_sec == 0) {
36                            fprintf(stderr, "touch: invalid time_t\n");
37                            exit(1);
38                        }
39                        specified_time.tv_nsec = 0;
40                        break;
41                    case 'l': flags |= AT_SYMLINK_NOFOLLOW; break;
42                    case 'd': debug = 1; break;
43                    default:
44                        usage();
45                    }
46                    arg++;
47                }
48            } else {
49                /* not an option, and only accept one filename */
50                if (i+1 != argc)
51                    usage();
52                file = argv[i];
53            }
54        }
55
56        if (! file) {
57            fprintf(stderr, "touch: no file specified\n");
58            exit(1);
59        }
60
61        if (access(file, F_OK))
62            if ((fd=creat(file, 0666)) != -1)
63                close(fd);
64
65        if ((mflag == 0) && (aflag == 0))
66            aflag = mflag = 1;
67
68        if (aflag)
69            times[0] = specified_time;
70        else
71            times[0].tv_nsec = UTIME_OMIT;
72
73        if (mflag)
74            times[1] = specified_time;
75        else
76            times[1].tv_nsec = UTIME_OMIT;
77
78        if (debug) {
79            fprintf(stderr, "file = %s\n", file);
80            fprintf(stderr, "times[0].tv_sec = %ld, times[0].tv_nsec = %ld\n", times[0].tv_sec, times[0].tv_nsec);
81            fprintf(stderr, "times[1].tv_sec = %ld, times[1].tv_nsec = %ld\n", times[1].tv_sec, times[1].tv_nsec);
82            fprintf(stderr, "flags = 0x%8.8x\n", flags);
83        }
84
85        return utimensat(AT_FDCWD, file, times, flags);
86}
87
88