OpenWrt – Blame information for rev 4

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4 office 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  
31 static void usage(const char *) __attribute__ (( __noreturn__ ));
32  
33 static 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  
41 static char *input_file = NULL;
42 static char *output_file = NULL;
43 static unsigned loadaddr = 0x80002000;
44  
45 static 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  
72 static 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  
86 int 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 }