Add patch-cmdline to patch the RB1xx kernel command line after installation
[openwrt/svn-archive/archive.git] / package / patch-cmdline / src / patch-cmdline.c
1 /*
2 * patch-cmdline.c - patch the kernel command line on rb532
3 *
4 * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 *
20 * $Id:$
21 */
22
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <stddef.h>
26 #include <unistd.h>
27 #include <fcntl.h>
28 #include <sys/mman.h>
29 #include <sys/stat.h>
30 #include <string.h>
31
32 #define SEARCH_SPACE (16 * 1024)
33 #define CMDLINE_MAX 512
34
35 int main(int argc, char **argv)
36 {
37 int fd, found = 0, len, ret = -1;
38 char *ptr, *p;
39
40 if (argc != 3) {
41 fprintf(stderr, "Usage: %s <file> <cmdline>\n", argv[0]);
42 goto err1;
43 }
44 len = strlen(argv[2]);
45 if (len + 9 > CMDLINE_MAX) {
46 fprintf(stderr, "Command line string too long\n");
47 goto err1;
48 }
49
50 if (((fd = open(argv[1], O_RDWR)) < 0) ||
51 (ptr = (char *) mmap(0, SEARCH_SPACE + CMDLINE_MAX, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == (void *) (-1)) {
52 fprintf(stderr, "Could not open kernel image");
53 goto err2;
54 }
55
56 for (p = ptr; p < (ptr + SEARCH_SPACE); p += 4) {
57 if (memcmp(p, "CMDLINE:", 8) == 0) {
58 found = 1;
59 p += 8;
60 break;
61 }
62 }
63 if (!found) {
64 fprintf(stderr, "Command line marker not found!\n");
65 goto err3;
66 }
67
68 memset(p, 0, CMDLINE_MAX - 8);
69 strcpy(p, argv[2]);
70 msync(p, CMDLINE_MAX, MS_SYNC|MS_INVALIDATE);
71 ret = 0;
72
73 err3:
74 munmap((void *) ptr, len);
75 err2:
76 if (fd > 0)
77 close(fd);
78 err1:
79 return ret;
80 }