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 # define elfhdr elf64_hdr 31 # define elf_phdr elf64_phdr 32 # define elf_check_arch(x) ((x)->e_machine == EM_ALPHA) 33 #endif 34 35 /* bootfile size must be multiple of BLOCK_SIZE: */ 36 #define BLOCK_SIZE 512 37 38 const char * prog_name; 39 40 41 static void 42 usage (void) 43 { 44 fprintf(stderr, 45 "usage: %s [-v] -p file primary\n" 46 " %s [-vb] file [secondary]\n", prog_name, prog_name); 47 exit(1); 48 } 49 50 51 int 52 main (int argc, char *argv[]) 53 { 54 size_t nwritten, tocopy, n, mem_size, fil_size, pad = 0; 55 int fd, ofd, i, j, verbose = 0, primary = 0; 56 char buf[8192], *inname; 57 struct exec * aout; /* includes file & aout header */ 58 long offset; 59 #ifdef __ELF__ 60 struct elfhdr *elf; 61 struct elf_phdr *elf_phdr; /* program header */ 62 unsigned long long e_entry; 63 #endif 64 65 prog_name = argv[0]; 66 67 for (i = 1; i < argc && argv[i][0] == '-'; ++i) { 68 for (j = 1; argv[i][j]; ++j) { 69 switch (argv[i][j]) { 70 case 'v': 71 verbose = ~verbose; 72 break; 73 74 case 'b': 75 pad = BLOCK_SIZE; 76 break; 77 78 case 'p': 79 primary = 1; /* make primary bootblock */ 80 break; 81 } 82 } 83 } 84 85 if (i >= argc) { 86 usage(); 87 } 88 inname = argv[i++]; 89 90 fd = open(inname, O_RDONLY); 91 if (fd == -1) { 92 perror("open"); 93 exit(1); 94 } 95 96 ofd = 1; 97 if (i < argc) { 98 ofd = open(argv[i++], O_WRONLY | O_CREAT | O_TRUNC, 0666); 99 if (ofd == -1) { 100 perror("open"); 101 exit(1); 102 } 103 } 104 105 if (primary) { 106 /* generate bootblock for primary loader */ 107 108 unsigned long bb[64], sum = 0; 109 struct stat st; 110 off_t size; 111 int i; 112 113 if (ofd == 1) { 114 usage(); 115 } 116 117 if (fstat(fd, &st) == -1) { 118 perror("fstat"); 119 exit(1); 120 } 121 122 size = (st.st_size + BLOCK_SIZE - 1) & ~(BLOCK_SIZE - 1); 123 memset(bb, 0, sizeof(bb)); 124 strcpy((char *) bb, "Linux SRM bootblock"); 125 bb[60] = size / BLOCK_SIZE; /* count */ 126 bb[61] = 1; /* starting sector # */ 127 bb[62] = 0; /* flags---must be 0 */ 128 for (i = 0; i < 63; ++i) { 129 sum += bb[i]; 130 } 131 bb[63] = sum; 132 if (write(ofd, bb, sizeof(bb)) != sizeof(bb)) { 133 perror("boot-block write"); 134 exit(1); 135 } 136 printf("%lu\n", size); 137 return 0; 138 } 139 140 /* read and inspect exec header: */ 141 142 if (read(fd, buf, sizeof(buf)) < 0) { 143 perror("read"); 144 exit(1); 145 } 146 147 #ifdef __ELF__ 148 elf = (struct elfhdr *) buf; 149 150 if (elf->e_ident[0] == 0x7f && strncmp((char *)elf->e_ident + 1, "ELF", 3) == 0) { 151 if (elf->e_type != ET_EXEC) { 152 fprintf(stderr, "%s: %s is not an ELF executable\n", 153 prog_name, inname); 154 exit(1); 155 } 156 if (!elf_check_arch(elf)) { 157 fprintf(stderr, "%s: is not for this processor (e_machine=%d)\n", 158 prog_name, elf->e_machine); 159 exit(1); 160 } 161 if (elf->e_phnum != 1) { 162 fprintf(stderr, 163 "%s: %d program headers (forgot to link with -N?)\n", 164 prog_name, elf->e_phnum); 165 } 166 167 e_entry = elf->e_entry; 168 169 lseek(fd, elf->e_phoff, SEEK_SET); 170 if (read(fd, buf, sizeof(*elf_phdr)) != sizeof(*elf_phdr)) { 171 perror("read"); 172 exit(1); 173 } 174 175 elf_phdr = (struct elf_phdr *) buf; 176 offset = elf_phdr->p_offset; 177 mem_size = elf_phdr->p_memsz; 178 fil_size = elf_phdr->p_filesz; 179 180 /* work around ELF bug: */ 181 if (elf_phdr->p_vaddr < e_entry) { 182 unsigned long delta = e_entry - elf_phdr->p_vaddr; 183 offset += delta; 184 mem_size -= delta; 185 fil_size -= delta; 186 elf_phdr->p_vaddr += delta; 187 } 188 189 if (verbose) { 190 fprintf(stderr, "%s: extracting %#016lx-%#016lx (at %lx)\n", 191 prog_name, (long) elf_phdr->p_vaddr, 192 elf_phdr->p_vaddr + fil_size, offset); 193 } 194 } else 195 #endif 196 { 197 aout = (struct exec *) buf; 198 199 if (!(aout->fh.f_flags & COFF_F_EXEC)) { 200 fprintf(stderr, "%s: %s is not in executable format\n", 201 prog_name, inname); 202 exit(1); 203 } 204 205 if (aout->fh.f_opthdr != sizeof(aout->ah)) { 206 fprintf(stderr, "%s: %s has unexpected optional header size\n", 207 prog_name, inname); 208 exit(1); 209 } 210 211 if (N_MAGIC(*aout) != OMAGIC) { 212 fprintf(stderr, "%s: %s is not an OMAGIC file\n", 213 prog_name, inname); 214 exit(1); 215 } 216 offset = N_TXTOFF(*aout); 217 fil_size = aout->ah.tsize + aout->ah.dsize; 218 mem_size = fil_size + aout->ah.bsize; 219 220 if (verbose) { 221 fprintf(stderr, "%s: extracting %#016lx-%#016lx (at %lx)\n", 222 prog_name, aout->ah.text_start, 223 aout->ah.text_start + fil_size, offset); 224 } 225 } 226 227 if (lseek(fd, offset, SEEK_SET) != offset) { 228 perror("lseek"); 229 exit(1); 230 } 231 232 if (verbose) { 233 fprintf(stderr, "%s: copying %lu byte from %s\n", 234 prog_name, (unsigned long) fil_size, inname); 235 } 236 237 tocopy = fil_size; 238 while (tocopy > 0) { 239 n = tocopy; 240 if (n > sizeof(buf)) { 241 n = sizeof(buf); 242 } 243 tocopy -= n; 244 if ((size_t) read(fd, buf, n) != n) { 245 perror("read"); 246 exit(1); 247 } 248 do { 249 nwritten = write(ofd, buf, n); 250 if ((ssize_t) nwritten == -1) { 251 perror("write"); 252 exit(1); 253 } 254 n -= nwritten; 255 } while (n > 0); 256 } 257 258 if (pad) { 259 mem_size = ((mem_size + pad - 1) / pad) * pad; 260 } 261 262 tocopy = mem_size - fil_size; 263 if (tocopy > 0) { 264 fprintf(stderr, 265 "%s: zero-filling bss and aligning to %lu with %lu bytes\n", 266 prog_name, pad, (unsigned long) tocopy); 267 268 memset(buf, 0x00, sizeof(buf)); 269 do { 270 n = tocopy; 271 if (n > sizeof(buf)) { 272 n = sizeof(buf); 273 } 274 nwritten = write(ofd, buf, n); 275 if ((ssize_t) nwritten == -1) { 276 perror("write"); 277 exit(1); 278 } 279 tocopy -= nwritten; 280 } while (tocopy > 0); 281 } 282 return 0; 283 } 284