1 /*
2 * arch/alpha/boot/tools/objstrip.c
3 *
4 * Strip the object file headers/trailers from an executable (ELF or ECOFF).
5 *
6 * Copyright (C) 1996 David Mosberger-Tang.
7 */
8 /*
9 * Converts an ECOFF or ELF object file into a bootable file. The
10 * object file must be a OMAGIC file (i.e., data and bss follow immediately
11 * behind the text). See DEC "Assembly Language Programmer's Guide"
12 * documentation for details. The SRM boot process is documented in
13 * the Alpha AXP Architecture Reference Manual, Second Edition by
14 * Richard L. Sites and Richard T. Witek.
15 */
16 #include <stdio.h>
17 #include <string.h>
18 #include <stdlib.h>
19 #include <unistd.h>
20
21 #include <sys/fcntl.h>
22 #include <sys/stat.h>
23 #include <sys/types.h>
24
25 #include <linux/a.out.h>
26 #include <linux/coff.h>
27 #include <linux/param.h>
28 #ifdef __ELF__
29 # include <linux/elf.h>
30 #endif
31
32 /* bootfile size must be multiple of BLOCK_SIZE: */
33 #define BLOCK_SIZE 512
34
35 const char * prog_name;
36
37
38 static void
usage(void)39 usage (void)
40 {
41 fprintf(stderr,
42 "usage: %s [-v] -p file primary\n"
43 " %s [-vb] file [secondary]\n", prog_name, prog_name);
44 exit(1);
45 }
46
47
48 int
main(int argc,char * argv[])49 main (int argc, char *argv[])
50 {
51 size_t nwritten, tocopy, n, mem_size, fil_size, pad = 0;
52 int fd, ofd, i, j, verbose = 0, primary = 0;
53 char buf[8192], *inname;
54 struct exec * aout; /* includes file & aout header */
55 long offset;
56 #ifdef __ELF__
57 struct elfhdr *elf;
58 struct elf_phdr *elf_phdr; /* program header */
59 unsigned long long e_entry;
60 #endif
61
62 prog_name = argv[0];
63
64 for (i = 1; i < argc && argv[i][0] == '-'; ++i) {
65 for (j = 1; argv[i][j]; ++j) {
66 switch (argv[i][j]) {
67 case 'v':
68 verbose = ~verbose;
69 break;
70
71 case 'b':
72 pad = BLOCK_SIZE;
73 break;
74
75 case 'p':
76 primary = 1; /* make primary bootblock */
77 break;
78 }
79 }
80 }
81
82 if (i >= argc) {
83 usage();
84 }
85 inname = argv[i++];
86
87 fd = open(inname, O_RDONLY);
88 if (fd == -1) {
89 perror("open");
90 exit(1);
91 }
92
93 ofd = 1;
94 if (i < argc) {
95 ofd = open(argv[i++], O_WRONLY | O_CREAT | O_TRUNC, 0666);
96 if (ofd == -1) {
97 perror("open");
98 exit(1);
99 }
100 }
101
102 if (primary) {
103 /* generate bootblock for primary loader */
104
105 unsigned long bb[64], sum = 0;
106 struct stat st;
107 off_t size;
108 int i;
109
110 if (ofd == 1) {
111 usage();
112 }
113
114 if (fstat(fd, &st) == -1) {
115 perror("fstat");
116 exit(1);
117 }
118
119 size = (st.st_size + BLOCK_SIZE - 1) & ~(BLOCK_SIZE - 1);
120 memset(bb, 0, sizeof(bb));
121 strcpy((char *) bb, "Linux SRM bootblock");
122 bb[60] = size / BLOCK_SIZE; /* count */
123 bb[61] = 1; /* starting sector # */
124 bb[62] = 0; /* flags---must be 0 */
125 for (i = 0; i < 63; ++i) {
126 sum += bb[i];
127 }
128 bb[63] = sum;
129 if (write(ofd, bb, sizeof(bb)) != sizeof(bb)) {
130 perror("boot-block write");
131 exit(1);
132 }
133 printf("%lu\n", size);
134 return 0;
135 }
136
137 /* read and inspect exec header: */
138
139 if (read(fd, buf, sizeof(buf)) < 0) {
140 perror("read");
141 exit(1);
142 }
143
144 #ifdef __ELF__
145 elf = (struct elfhdr *) buf;
146
147 if (elf->e_ident[0] == 0x7f && strncmp((char *)elf->e_ident + 1, "ELF", 3) == 0) {
148 if (elf->e_type != ET_EXEC) {
149 fprintf(stderr, "%s: %s is not an ELF executable\n",
150 prog_name, inname);
151 exit(1);
152 }
153 if (!elf_check_arch(elf)) {
154 fprintf(stderr, "%s: is not for this processor (e_machine=%d)\n",
155 prog_name, elf->e_machine);
156 exit(1);
157 }
158 if (elf->e_phnum != 1) {
159 fprintf(stderr,
160 "%s: %d program headers (forgot to link with -N?)\n",
161 prog_name, elf->e_phnum);
162 }
163
164 e_entry = elf->e_entry;
165
166 lseek(fd, elf->e_phoff, SEEK_SET);
167 if (read(fd, buf, sizeof(*elf_phdr)) != sizeof(*elf_phdr)) {
168 perror("read");
169 exit(1);
170 }
171
172 elf_phdr = (struct elf_phdr *) buf;
173 offset = elf_phdr->p_offset;
174 mem_size = elf_phdr->p_memsz;
175 fil_size = elf_phdr->p_filesz;
176
177 /* work around ELF bug: */
178 if (elf_phdr->p_vaddr < e_entry) {
179 unsigned long delta = e_entry - elf_phdr->p_vaddr;
180 offset += delta;
181 mem_size -= delta;
182 fil_size -= delta;
183 elf_phdr->p_vaddr += delta;
184 }
185
186 if (verbose) {
187 fprintf(stderr, "%s: extracting %#016lx-%#016lx (at %lx)\n",
188 prog_name, (long) elf_phdr->p_vaddr,
189 elf_phdr->p_vaddr + fil_size, offset);
190 }
191 } else
192 #endif
193 {
194 aout = (struct exec *) buf;
195
196 if (!(aout->fh.f_flags & COFF_F_EXEC)) {
197 fprintf(stderr, "%s: %s is not in executable format\n",
198 prog_name, inname);
199 exit(1);
200 }
201
202 if (aout->fh.f_opthdr != sizeof(aout->ah)) {
203 fprintf(stderr, "%s: %s has unexpected optional header size\n",
204 prog_name, inname);
205 exit(1);
206 }
207
208 if (N_MAGIC(*aout) != OMAGIC) {
209 fprintf(stderr, "%s: %s is not an OMAGIC file\n",
210 prog_name, inname);
211 exit(1);
212 }
213 offset = N_TXTOFF(*aout);
214 fil_size = aout->ah.tsize + aout->ah.dsize;
215 mem_size = fil_size + aout->ah.bsize;
216
217 if (verbose) {
218 fprintf(stderr, "%s: extracting %#016lx-%#016lx (at %lx)\n",
219 prog_name, aout->ah.text_start,
220 aout->ah.text_start + fil_size, offset);
221 }
222 }
223
224 if (lseek(fd, offset, SEEK_SET) != offset) {
225 perror("lseek");
226 exit(1);
227 }
228
229 if (verbose) {
230 fprintf(stderr, "%s: copying %lu byte from %s\n",
231 prog_name, (unsigned long) fil_size, inname);
232 }
233
234 tocopy = fil_size;
235 while (tocopy > 0) {
236 n = tocopy;
237 if (n > sizeof(buf)) {
238 n = sizeof(buf);
239 }
240 tocopy -= n;
241 if ((size_t) read(fd, buf, n) != n) {
242 perror("read");
243 exit(1);
244 }
245 do {
246 nwritten = write(ofd, buf, n);
247 if ((ssize_t) nwritten == -1) {
248 perror("write");
249 exit(1);
250 }
251 n -= nwritten;
252 } while (n > 0);
253 }
254
255 if (pad) {
256 mem_size = ((mem_size + pad - 1) / pad) * pad;
257 }
258
259 tocopy = mem_size - fil_size;
260 if (tocopy > 0) {
261 fprintf(stderr,
262 "%s: zero-filling bss and aligning to %lu with %lu bytes\n",
263 prog_name, pad, (unsigned long) tocopy);
264
265 memset(buf, 0x00, sizeof(buf));
266 do {
267 n = tocopy;
268 if (n > sizeof(buf)) {
269 n = sizeof(buf);
270 }
271 nwritten = write(ofd, buf, n);
272 if ((ssize_t) nwritten == -1) {
273 perror("write");
274 exit(1);
275 }
276 tocopy -= nwritten;
277 } while (tocopy > 0);
278 }
279 return 0;
280 }
281