| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 1 | /* |
| 2 | * patch-cmdline.c - patch the kernel command line |
| 3 | * |
| 4 | * Copyright (C) 2006 Felix Fietkau <nbd@nbd.name> |
| 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 | */ |
| 21 | |
| 22 | #include <stdio.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <stddef.h> |
| 25 | #include <unistd.h> |
| 26 | #include <fcntl.h> |
| 27 | #include <sys/mman.h> |
| 28 | #include <sys/stat.h> |
| 29 | #include <string.h> |
| 30 | |
| 31 | #define SEARCH_SPACE (16 * 1024) |
| 32 | #define CMDLINE_MAX 512 |
| 33 | |
| 34 | int main(int argc, char **argv) |
| 35 | { |
| 36 | int fd, found = 0, len, ret = -1; |
| 37 | char *ptr, *p; |
| 38 | unsigned int search_space; |
| 39 | |
| 40 | if (argc <= 2 || argc > 4) { |
| 41 | fprintf(stderr, "Usage: %s <file> <cmdline> [size]\n", argv[0]); |
| 42 | goto err1; |
| 43 | } else if (argc == 3) { |
| 44 | fprintf(stdout, "search space used is default of 16KB\n"); |
| 45 | search_space = SEARCH_SPACE; |
| 46 | } else { |
| 47 | search_space = atoi(argv[3]); |
| 48 | } |
| 49 | len = strlen(argv[2]); |
| 50 | if (len + 9 > CMDLINE_MAX) { |
| 51 | fprintf(stderr, "Command line string too long\n"); |
| 52 | goto err1; |
| 53 | } |
| 54 | |
| 55 | if (((fd = open(argv[1], O_RDWR)) < 0) || |
| 56 | (ptr = (char *) mmap(0, search_space + CMDLINE_MAX, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == (void *) (-1)) { |
| 57 | fprintf(stderr, "Could not open kernel image"); |
| 58 | goto err2; |
| 59 | } |
| 60 | |
| 61 | for (p = ptr; p < (ptr + search_space); p += 4) { |
| 62 | if (memcmp(p, "CMDLINE:", 8) == 0) { |
| 63 | found = 1; |
| 64 | p += 8; |
| 65 | break; |
| 66 | } |
| 67 | } |
| 68 | if (!found) { |
| 69 | fprintf(stderr, "Command line marker not found!\n"); |
| 70 | goto err3; |
| 71 | } |
| 72 | |
| 73 | memset(p, 0, CMDLINE_MAX - 8); |
| 74 | strcpy(p, argv[2]); |
| 75 | msync(p, CMDLINE_MAX, MS_SYNC|MS_INVALIDATE); |
| 76 | ret = 0; |
| 77 | |
| 78 | err3: |
| 79 | munmap((void *) ptr, len); |
| 80 | err2: |
| 81 | if (fd > 0) |
| 82 | close(fd); |
| 83 | err1: |
| 84 | return ret; |
| 85 | } |