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 # 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 }