1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/alpha/boot/tools/objstrip.c
4 *
5 * Strip the object file headers/trailers from an executable (ELF or ECOFF).
6 *
7 * Copyright (C) 1996 David Mosberger-Tang.
8 */
9 /*
10 * Converts an ECOFF or ELF object file into a bootable file. The
11 * object file must be a OMAGIC file (i.e., data and bss follow immediately
12 * behind the text). See DEC "Assembly Language Programmer's Guide"
13 * documentation for details. The SRM boot process is documented in
14 * the Alpha AXP Architecture Reference Manual, Second Edition by
15 * Richard L. Sites and Richard T. Witek.
16 */
17 #include <stdio.h>
18 #include <string.h>
19 #include <stdlib.h>
20 #include <unistd.h>
21
22 #include <sys/fcntl.h>
23 #include <sys/stat.h>
24 #include <sys/types.h>
25
26 #include <linux/a.out.h>
27 #include <linux/coff.h>
28 #include <linux/param.h>
29 #ifdef __ELF__
30 # include <linux/elf.h>
31 # define elfhdr elf64_hdr
32 # define elf_phdr elf64_phdr
33 # define elf_check_arch(x) ((x)->e_machine == EM_ALPHA)
34 #endif
35
36 /* bootfile size must be multiple of BLOCK_SIZE: */
37 #define BLOCK_SIZE 512
38
39 const char * prog_name;
40
41
42 static void
usage(void)43 usage (void)
44 {
45 fprintf(stderr,
46 "usage: %s [-v] -p file primary\n"
47 " %s [-vb] file [secondary]\n", prog_name, prog_name);
48 exit(1);
49 }
50
51
52 int
main(int argc,char * argv[])53 main (int argc, char *argv[])
54 {
55 size_t nwritten, tocopy, n, mem_size, fil_size, pad = 0;
56 int fd, ofd, i, j, verbose = 0, primary = 0;
57 char buf[8192], *inname;
58 struct exec * aout; /* includes file & aout header */
59 long offset;
60 #ifdef __ELF__
61 struct elfhdr *elf;
62 struct elf_phdr *elf_phdr; /* program header */
63 unsigned long long e_entry;
64 #endif
65
66 prog_name = argv[0];
67
68 for (i = 1; i < argc && argv[i][0] == '-'; ++i) {
69 for (j = 1; argv[i][j]; ++j) {
70 switch (argv[i][j]) {
71 case 'v':
72 verbose = ~verbose;
73 break;
74
75 case 'b':
76 pad = BLOCK_SIZE;
77 break;
78
79 case 'p':
80 primary = 1; /* make primary bootblock */
81 break;
82 }
83 }
84 }
85
86 if (i >= argc) {
87 usage();
88 }
89 inname = argv[i++];
90
91 fd = open(inname, O_RDONLY);
92 if (fd == -1) {
93 perror("open");
94 exit(1);
95 }
96
97 ofd = 1;
98 if (i < argc) {
99 ofd = open(argv[i++], O_WRONLY | O_CREAT | O_TRUNC, 0666);
100 if (ofd == -1) {
101 perror("open");
102 exit(1);
103 }
104 }
105
106 if (primary) {
107 /* generate bootblock for primary loader */
108
109 unsigned long bb[64], sum = 0;
110 struct stat st;
111 off_t size;
112 int i;
113
114 if (ofd == 1) {
115 usage();
116 }
117
118 if (fstat(fd, &st) == -1) {
119 perror("fstat");
120 exit(1);
121 }
122
123 size = (st.st_size + BLOCK_SIZE - 1) & ~(BLOCK_SIZE - 1);
124 memset(bb, 0, sizeof(bb));
125 strcpy((char *) bb, "Linux SRM bootblock");
126 bb[60] = size / BLOCK_SIZE; /* count */
127 bb[61] = 1; /* starting sector # */
128 bb[62] = 0; /* flags---must be 0 */
129 for (i = 0; i < 63; ++i) {
130 sum += bb[i];
131 }
132 bb[63] = sum;
133 if (write(ofd, bb, sizeof(bb)) != sizeof(bb)) {
134 perror("boot-block write");
135 exit(1);
136 }
137 printf("%lu\n", size);
138 return 0;
139 }
140
141 /* read and inspect exec header: */
142
143 if (read(fd, buf, sizeof(buf)) < 0) {
144 perror("read");
145 exit(1);
146 }
147
148 #ifdef __ELF__
149 elf = (struct elfhdr *) buf;
150
151 if (memcmp(&elf->e_ident[EI_MAG0], ELFMAG, SELFMAG) == 0) {
152 if (elf->e_type != ET_EXEC) {
153 fprintf(stderr, "%s: %s is not an ELF executable\n",
154 prog_name, inname);
155 exit(1);
156 }
157 if (!elf_check_arch(elf)) {
158 fprintf(stderr, "%s: is not for this processor (e_machine=%d)\n",
159 prog_name, elf->e_machine);
160 exit(1);
161 }
162 if (elf->e_phnum != 1) {
163 fprintf(stderr,
164 "%s: %d program headers (forgot to link with -N?)\n",
165 prog_name, elf->e_phnum);
166 }
167
168 e_entry = elf->e_entry;
169
170 lseek(fd, elf->e_phoff, SEEK_SET);
171 if (read(fd, buf, sizeof(*elf_phdr)) != sizeof(*elf_phdr)) {
172 perror("read");
173 exit(1);
174 }
175
176 elf_phdr = (struct elf_phdr *) buf;
177 offset = elf_phdr->p_offset;
178 mem_size = elf_phdr->p_memsz;
179 fil_size = elf_phdr->p_filesz;
180
181 /* work around ELF bug: */
182 if (elf_phdr->p_vaddr < e_entry) {
183 unsigned long delta = e_entry - elf_phdr->p_vaddr;
184 offset += delta;
185 mem_size -= delta;
186 fil_size -= delta;
187 elf_phdr->p_vaddr += delta;
188 }
189
190 if (verbose) {
191 fprintf(stderr, "%s: extracting %#016lx-%#016lx (at %lx)\n",
192 prog_name, (long) elf_phdr->p_vaddr,
193 elf_phdr->p_vaddr + fil_size, offset);
194 }
195 } else
196 #endif
197 {
198 aout = (struct exec *) buf;
199
200 if (!(aout->fh.f_flags & COFF_F_EXEC)) {
201 fprintf(stderr, "%s: %s is not in executable format\n",
202 prog_name, inname);
203 exit(1);
204 }
205
206 if (aout->fh.f_opthdr != sizeof(aout->ah)) {
207 fprintf(stderr, "%s: %s has unexpected optional header size\n",
208 prog_name, inname);
209 exit(1);
210 }
211
212 if (N_MAGIC(*aout) != OMAGIC) {
213 fprintf(stderr, "%s: %s is not an OMAGIC file\n",
214 prog_name, inname);
215 exit(1);
216 }
217 offset = N_TXTOFF(*aout);
218 fil_size = aout->ah.tsize + aout->ah.dsize;
219 mem_size = fil_size + aout->ah.bsize;
220
221 if (verbose) {
222 fprintf(stderr, "%s: extracting %#016lx-%#016lx (at %lx)\n",
223 prog_name, aout->ah.text_start,
224 aout->ah.text_start + fil_size, offset);
225 }
226 }
227
228 if (lseek(fd, offset, SEEK_SET) != offset) {
229 perror("lseek");
230 exit(1);
231 }
232
233 if (verbose) {
234 fprintf(stderr, "%s: copying %lu byte from %s\n",
235 prog_name, (unsigned long) fil_size, inname);
236 }
237
238 tocopy = fil_size;
239 while (tocopy > 0) {
240 n = tocopy;
241 if (n > sizeof(buf)) {
242 n = sizeof(buf);
243 }
244 tocopy -= n;
245 if ((size_t) read(fd, buf, n) != n) {
246 perror("read");
247 exit(1);
248 }
249 do {
250 nwritten = write(ofd, buf, n);
251 if ((ssize_t) nwritten == -1) {
252 perror("write");
253 exit(1);
254 }
255 n -= nwritten;
256 } while (n > 0);
257 }
258
259 if (pad) {
260 mem_size = ((mem_size + pad - 1) / pad) * pad;
261 }
262
263 tocopy = mem_size - fil_size;
264 if (tocopy > 0) {
265 fprintf(stderr,
266 "%s: zero-filling bss and aligning to %lu with %lu bytes\n",
267 prog_name, pad, (unsigned long) tocopy);
268
269 memset(buf, 0x00, sizeof(buf));
270 do {
271 n = tocopy;
272 if (n > sizeof(buf)) {
273 n = sizeof(buf);
274 }
275 nwritten = write(ofd, buf, n);
276 if ((ssize_t) nwritten == -1) {
277 perror("write");
278 exit(1);
279 }
280 tocopy -= nwritten;
281 } while (tocopy > 0);
282 }
283 return 0;
284 }
285