arch/alpha/boot/tools/objstrip.c

   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 && strncmp((char *)elf->e_ident + 1, "ELF", 3) == 0) {
 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 }