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