arch/alpha/boot/tools/objstrip.c

   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
  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
  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 }