linux/arch/alpha/boot/tools/objstrip.c
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   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
  39const char * prog_name;
  40
  41
  42static void
  43usage (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
  52int
  53main (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 && str_has_prefix((char *)elf->e_ident + 1, "ELF")) {
 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}
 285