src/unexmips.c

   1 /* Unexec for MIPS (including IRIS4D).
   2    Note that the GNU project considers support for MIPS operation
   3    a peripheral activity which should not be allowed to divert effort
   4    from development of the GNU system.  Changes in this code will be
   5    installed when users send them in, but aside from that
   6    we don't plan to think about it, or about whether other Emacs
   7    maintenance might break it.
   8
   9    Copyright (C) 1988 Free Software Foundation, Inc.
  10
  11 This file is part of GNU Emacs.
  12
  13 GNU Emacs is free software; you can redistribute it and/or modify
  14 it under the terms of the GNU General Public License as published by
  15 the Free Software Foundation; either version 1, or (at your option)
  16 any later version.
  17
  18 GNU Emacs is distributed in the hope that it will be useful,
  19 but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 GNU General Public License for more details.
  22
  23 You should have received a copy of the GNU General Public License
  24 along with GNU Emacs; see the file COPYING.  If not, write to
  25 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  26
  27 \f
  28 #include "config.h"
  29 #include <sys/types.h>
  30 #include <sys/file.h>
  31 #include <sys/stat.h>
  32 #include <stdio.h>
  33 #include <varargs.h>
  34 #include <filehdr.h>
  35 #include <aouthdr.h>
  36 #include <scnhdr.h>
  37 #include <sym.h>
  38
  39 #ifdef IRIS_4D
  40 #include "getpagesize.h"
  41 #endif
  42
  43 static void fatal_unexec ();
  44
  45 #define READ(_fd, _buffer, _size, _error_message, _error_arg) \
  46         errno = EEOF; \
  47         if (read (_fd, _buffer, _size) != _size) \
  48           fatal_unexec (_error_message, _error_arg);
  49
  50 #define WRITE(_fd, _buffer, _size, _error_message, _error_arg) \
  51         if (write (_fd, _buffer, _size) != _size) \
  52           fatal_unexec (_error_message, _error_arg);
  53
  54 #define SEEK(_fd, _position, _error_message, _error_arg) \
  55         errno = EEOF; \
  56         if (lseek (_fd, _position, L_SET) != _position) \
  57           fatal_unexec (_error_message, _error_arg);
  58
  59 extern int errno;
  60 extern int sys_nerr;
  61 extern char *sys_errlist[];
  62 #define EEOF -1
  63
  64 static struct scnhdr *text_section;
  65 static struct scnhdr *init_section;
  66 static struct scnhdr *finit_section;
  67 static struct scnhdr *rdata_section;
  68 static struct scnhdr *data_section;
  69 static struct scnhdr *lit8_section;
  70 static struct scnhdr *lit4_section;
  71 static struct scnhdr *sdata_section;
  72 static struct scnhdr *sbss_section;
  73 static struct scnhdr *bss_section;
  74
  75 struct headers {
  76     struct filehdr fhdr;
  77     struct aouthdr aout;
  78     struct scnhdr section[10];
  79 };
  80
  81 /* Define name of label for entry point for the dumped executable.  */
  82
  83 #ifndef DEFAULT_ENTRY_ADDRESS
  84 #define DEFAULT_ENTRY_ADDRESS __start
  85 #endif
  86 \f
  87 unexec (new_name, a_name, data_start, bss_start, entry_address)
  88      char *new_name, *a_name;
  89      unsigned data_start, bss_start, entry_address;
  90 {
  91   int new, old;
  92   int pagesize, brk;
  93   int newsyms, symrel;
  94   int nread;
  95   struct headers hdr;
  96   int i;
  97   int vaddr, scnptr;
  98 #define BUFSIZE 8192
  99   char buffer[BUFSIZE];
 100
 101   old = open (a_name, O_RDONLY, 0);
 102   if (old < 0) fatal_unexec ("opening %s", a_name);
 103
 104   new = creat (new_name, 0666);
 105   if (new < 0) fatal_unexec ("creating %s", new_name);
 106
 107   hdr = *((struct headers *)TEXT_START);
 108 #ifdef MIPS2
 109   if (hdr.fhdr.f_magic != MIPSELMAGIC
 110       && hdr.fhdr.f_magic != MIPSEBMAGIC
 111       && hdr.fhdr.f_magic != (MIPSELMAGIC | 1)
 112       && hdr.fhdr.f_magic != (MIPSEBMAGIC | 1))
 113     {
 114       fprintf(stderr,
 115               "unexec: input file magic number is %x, not %x, %x, %x or %x.\n",
 116               hdr.fhdr.f_magic,
 117               MIPSELMAGIC, MIPSEBMAGIC,
 118               MIPSELMAGIC | 1, MIPSEBMAGIC | 1);
 119       exit(1);
 120     }
 121 #else /* not MIPS2 */
 122   if (hdr.fhdr.f_magic != MIPSELMAGIC
 123       && hdr.fhdr.f_magic != MIPSEBMAGIC)
 124     {
 125       fprintf (stderr, "unexec: input file magic number is %x, not %x or %x.\n",
 126                hdr.fhdr.f_magic, MIPSELMAGIC, MIPSEBMAGIC);
 127       exit (1);
 128     }
 129 #endif /* not MIPS2 */
 130   if (hdr.fhdr.f_opthdr != sizeof (hdr.aout))
 131     {
 132       fprintf (stderr, "unexec: input a.out header is %d bytes, not %d.\n",
 133                hdr.fhdr.f_opthdr, sizeof (hdr.aout));
 134       exit (1);
 135     }
 136   if (hdr.aout.magic != ZMAGIC)
 137     {
 138       fprintf (stderr, "unexec: input file a.out magic number is %o, not %o.\n",
 139                hdr.aout.magic, ZMAGIC);
 140       exit (1);
 141     }
 142
 143 #define CHECK_SCNHDR(ptr, name, flags)                                  \
 144   if (strcmp (hdr.section[i].s_name, name) == 0)                        \
 145     {                                                                   \
 146       if (hdr.section[i].s_flags != flags)                              \
 147         fprintf (stderr, "unexec: %x flags (%x expected) in %s section.\n", \
 148                  hdr.section[i].s_flags, flags, name);                  \
 149       ptr = hdr.section + i;                                            \
 150       i += 1;                                                           \
 151     }                                                                   \
 152   else                                                                  \
 153     ptr = NULL;
 154
 155   i = 0;
 156   CHECK_SCNHDR (text_section,  _TEXT,  STYP_TEXT);
 157   CHECK_SCNHDR (init_section,  _INIT,  STYP_INIT);
 158   CHECK_SCNHDR (rdata_section, _RDATA, STYP_RDATA);
 159   CHECK_SCNHDR (data_section,  _DATA,  STYP_DATA);
 160 #ifdef _LIT8
 161   CHECK_SCNHDR (lit8_section,  _LIT8,  STYP_LIT8);
 162   CHECK_SCNHDR (lit4_section,  _LIT4,  STYP_LIT4);
 163 #endif /* _LIT8 */
 164   CHECK_SCNHDR (sdata_section, _SDATA, STYP_SDATA);
 165   CHECK_SCNHDR (sbss_section,  _SBSS,  STYP_SBSS);
 166   CHECK_SCNHDR (bss_section,   _BSS,   STYP_BSS);
 167   if (i != hdr.fhdr.f_nscns)
 168     fprintf (stderr, "unexec: %d sections found instead of %d.\n",
 169              i, hdr.fhdr.f_nscns);
 170
 171   pagesize = getpagesize ();
 172   brk = (sbrk (0) + pagesize - 1) & (-pagesize);
 173   hdr.aout.dsize = brk - DATA_START;
 174   hdr.aout.bsize = 0;
 175   if (entry_address == 0)
 176     {
 177       extern DEFAULT_ENTRY_ADDRESS ();
 178       hdr.aout.entry = (unsigned)DEFAULT_ENTRY_ADDRESS;
 179     }
 180   else
 181     hdr.aout.entry = entry_address;
 182
 183   hdr.aout.bss_start = hdr.aout.data_start + hdr.aout.dsize;
 184   rdata_section->s_size = data_start - DATA_START;
 185   data_section->s_vaddr = data_start;
 186   data_section->s_paddr = data_start;
 187   data_section->s_size = brk - DATA_START;
 188   data_section->s_scnptr = rdata_section->s_scnptr + rdata_section->s_size;
 189   vaddr = data_section->s_vaddr + data_section->s_size;
 190   scnptr = data_section->s_scnptr + data_section->s_size;
 191   if (lit8_section != NULL)
 192     {
 193       lit8_section->s_vaddr = vaddr;
 194       lit8_section->s_paddr = vaddr;
 195       lit8_section->s_size = 0;
 196       lit8_section->s_scnptr = scnptr;
 197     }
 198   if (lit4_section != NULL)
 199     {
 200       lit4_section->s_vaddr = vaddr;
 201       lit4_section->s_paddr = vaddr;
 202       lit4_section->s_size = 0;
 203       lit4_section->s_scnptr = scnptr;
 204     }
 205   if (sdata_section != NULL)
 206     {
 207       sdata_section->s_vaddr = vaddr;
 208       sdata_section->s_paddr = vaddr;
 209       sdata_section->s_size = 0;
 210       sdata_section->s_scnptr = scnptr;
 211     }
 212   if (sbss_section != NULL)
 213     {
 214       sbss_section->s_vaddr = vaddr;
 215       sbss_section->s_paddr = vaddr;
 216       sbss_section->s_size = 0;
 217       sbss_section->s_scnptr = scnptr;
 218     }
 219   if (bss_section != NULL)
 220     {
 221       bss_section->s_vaddr = vaddr;
 222       bss_section->s_paddr = vaddr;
 223       bss_section->s_size = 0;
 224       bss_section->s_scnptr = scnptr;
 225     }
 226
 227   WRITE (new, TEXT_START, hdr.aout.tsize,
 228          "writing text section to %s", new_name);
 229   WRITE (new, DATA_START, hdr.aout.dsize,
 230          "writing text section to %s", new_name);
 231
 232   SEEK (old, hdr.fhdr.f_symptr, "seeking to start of symbols in %s", a_name);
 233   errno = EEOF;
 234   nread = read (old, buffer, BUFSIZE);
 235   if (nread < sizeof (HDRR)) fatal_unexec ("reading symbols from %s", a_name);
 236 #define symhdr ((pHDRR)buffer)
 237   newsyms = hdr.aout.tsize + hdr.aout.dsize;
 238   symrel = newsyms - hdr.fhdr.f_symptr;
 239   hdr.fhdr.f_symptr = newsyms;
 240   symhdr->cbLineOffset += symrel;
 241   symhdr->cbDnOffset += symrel;
 242   symhdr->cbPdOffset += symrel;
 243   symhdr->cbSymOffset += symrel;
 244   symhdr->cbOptOffset += symrel;
 245   symhdr->cbAuxOffset += symrel;
 246   symhdr->cbSsOffset += symrel;
 247   symhdr->cbSsExtOffset += symrel;
 248   symhdr->cbFdOffset += symrel;
 249   symhdr->cbRfdOffset += symrel;
 250   symhdr->cbExtOffset += symrel;
 251 #undef symhdr
 252   do
 253     {
 254       if (write (new, buffer, nread) != nread)
 255         fatal_unexec ("writing symbols to %s", new_name);
 256       nread = read (old, buffer, BUFSIZE);
 257       if (nread < 0) fatal_unexec ("reading symbols from %s", a_name);
 258 #undef BUFSIZE
 259     } while (nread != 0);
 260
 261   SEEK (new, 0, "seeking to start of header in %s", new_name);
 262   WRITE (new, &hdr, sizeof (hdr),
 263          "writing header of %s", new_name);
 264
 265   close (old);
 266   close (new);
 267   mark_x (new_name);
 268 }
 269 \f
 270 /*
 271  * mark_x
 272  *
 273  * After succesfully building the new a.out, mark it executable
 274  */
 275
 276 static
 277 mark_x (name)
 278      char *name;
 279 {
 280   struct stat sbuf;
 281   int um = umask (777);
 282   umask (um);
 283   if (stat (name, &sbuf) < 0)
 284     fatal_unexec ("getting protection on %s", name);
 285   sbuf.st_mode |= 0111 & ~um;
 286   if (chmod (name, sbuf.st_mode) < 0)
 287     fatal_unexec ("setting protection on %s", name);
 288 }
 289
 290 static void
 291 fatal_unexec (s, va_alist)
 292      va_dcl
 293 {
 294   va_list ap;
 295   if (errno == EEOF)
 296     fputs ("unexec: unexpected end of file, ", stderr);
 297   else if (errno < sys_nerr)
 298     fprintf (stderr, "unexec: %s, ", sys_errlist[errno]);
 299   else
 300     fprintf (stderr, "unexec: error code %d, ", errno);
 301   va_start (ap);
 302   _doprnt (s, ap, stderr);
 303   fputs (".\n", stderr);
 304   exit (1);
 305 }