1/* 2 * mkbrncmdline.c - partially based on OpenWrt's wndr3700.c 3 * 4 * Copyright (C) 2011 Tobias Diedrich <ranma+openwrt@tdiedrich.de> 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 * version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 18 */ 19 20#include <stdio.h> 21#include <stdlib.h> 22#include <stddef.h> 23#include <unistd.h> 24#include <errno.h> 25#include <fcntl.h> 26#include <sys/mman.h> 27#include <string.h> 28#include <netinet/in.h> 29#include <inttypes.h> 30 31static void usage(const char *) __attribute__ (( __noreturn__ )); 32 33static void usage(const char *mess) 34{ 35 fprintf(stderr, "Error: %s\n", mess); 36 fprintf(stderr, "Usage: mkbrncmdline -i input_file -o output_file [-a loadaddress] arg1 [argx ...]\n"); 37 fprintf(stderr, "\n"); 38 exit(1); 39} 40 41static char *input_file = NULL; 42static char *output_file = NULL; 43static unsigned loadaddr = 0x80002000; 44 45static void parseopts(int *argc, char ***argv) 46{ 47 char *endptr; 48 int res; 49 50 while ((res = getopt(*argc, *argv, "a:i:o:")) != -1) { 51 switch (res) { 52 default: 53 usage("Unknown option"); 54 break; 55 case 'a': 56 loadaddr = strtoul(optarg, &endptr, 0); 57 if (endptr == optarg || *endptr != 0) 58 usage("loadaddress must be a decimal or hexadecimal 32-bit value"); 59 break; 60 case 'i': 61 input_file = optarg; 62 break; 63 case 'o': 64 output_file = optarg; 65 break; 66 } 67 } 68 *argc -= optind; 69 *argv += optind; 70} 71 72static void emitload(int outfd, int reg, unsigned value) 73{ 74 char buf[8] = { 75 0x3c, 0x04 + reg, 76 value >> 24, value >> 16, 77 0x34, 0x84 + reg + (reg << 5), 78 value >> 8, value, 79 }; 80 if (write(outfd, buf, sizeof(buf)) != sizeof(buf)) { 81 fprintf(stderr, "write: %s\n", strerror(errno)); 82 exit(1); 83 } 84} 85 86int main(int argc, char **argv) 87{ 88 int outfd; 89 int i; 90 int fd; 91 size_t len, skip, buf_len; 92 unsigned cmdline_addr; 93 unsigned s_ofs; 94 char *buf; 95 96 parseopts(&argc, &argv); 97 98 if (argc < 1) 99 usage("must specify at least one kernel cmdline argument"); 100 101 if (input_file == NULL || output_file == NULL) 102 usage("must specify input and output file"); 103 104 if ((outfd = open(output_file, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1) 105 { 106 fprintf(stderr, "Error opening '%s' for writing: %s\n", output_file, strerror(errno)); 107 exit(1); 108 } 109 110 // mmap input_file 111 if ((fd = open(input_file, O_RDONLY)) < 0 112 || (len = lseek(fd, 0, SEEK_END)) < 0 113 || (input_file = mmap(0, len, PROT_READ, MAP_SHARED, fd, 0)) == (void *) (-1) 114 || close(fd) < 0) 115 { 116 fprintf(stderr, "Error mapping file '%s': %s\n", input_file, strerror(errno)); 117 exit(1); 118 } 119 120 cmdline_addr = loadaddr + len; 121 122 // Kernel args are passed in registers a0,a1,a2 and a3 123 emitload(outfd, 0, 0); /* a0 = 0 */ 124 emitload(outfd, 1, 0); /* a1 = 0 */ 125 emitload(outfd, 2, cmdline_addr); /* a2 = &cmdline */ 126 emitload(outfd, 3, 0); /* a3 = 0 */ 127 skip = lseek(outfd, 0, SEEK_END); 128 129 // write the kernel 130 if (write(outfd, input_file + skip, len - skip) != len -skip) { 131 fprintf(stderr, "write: %s\n", strerror(errno)); 132 exit(1); 133 } 134 135 // write cmdline structure 136 buf_len = (argc + 1) * 4; 137 for (i=0; i<argc; i++) { 138 buf_len += strlen(argv[i]) + 1; 139 } 140 buf = malloc(buf_len + 16); 141 if (!buf) { 142 fprintf(stderr, "Could not allocate memory for cmdline buffer\n"); 143 exit(1); 144 } 145 memset(buf, 0, buf_len); 146 147 s_ofs = 4 * (argc + 1); 148 for (i=0; i<argc; i++) { 149 unsigned s_ptr = cmdline_addr + s_ofs; 150 buf[i * 4 + 0] = s_ptr >> 24; 151 buf[i * 4 + 1] = s_ptr >> 16; 152 buf[i * 4 + 2] = s_ptr >> 8; 153 buf[i * 4 + 3] = s_ptr >> 0; 154 memcpy(&buf[s_ofs], argv[i], strlen(argv[i])); 155 s_ofs += strlen(argv[i]) + 1; 156 } 157 if (write(outfd, buf, buf_len) != buf_len) { 158 fprintf(stderr, "write: %s\n", strerror(errno)); 159 exit(1); 160 } 161 162 163 munmap(input_file, len); 164 close(outfd); 165 free(buf); 166 167 return 0; 168} 169