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 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 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 (elf->e_ident[0] == 0x7f && str_has_prefix((char *)elf->e_ident + 1, "ELF")) { 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