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, 1994 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 2, 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 #if defined (IRIS_4D) || defined (sony)
  40 #include "getpagesize.h"
  41 #include <fcntl.h>
  42 #endif
  43
  44 static void fatal_unexec ();
  45 static void mark_x ();
  46
  47 #define READ(_fd, _buffer, _size, _error_message, _error_arg) \
  48         errno = EEOF; \
  49         if (read (_fd, _buffer, _size) != _size) \
  50           fatal_unexec (_error_message, _error_arg);
  51
  52 #define WRITE(_fd, _buffer, _size, _error_message, _error_arg) \
  53         if (write (_fd, _buffer, _size) != _size) \
  54           fatal_unexec (_error_message, _error_arg);
  55
  56 #define SEEK(_fd, _position, _error_message, _error_arg) \
  57         errno = EEOF; \
  58         if (lseek (_fd, _position, L_SET) != _position) \
  59           fatal_unexec (_error_message, _error_arg);
  60
  61 extern int errno;
  62 extern char *strerror ();
  63 #define EEOF -1
  64
  65 static struct scnhdr *text_section;
  66 static struct scnhdr *init_section;
  67 static struct scnhdr *finit_section;
  68 static struct scnhdr *rdata_section;
  69 static struct scnhdr *data_section;
  70 static struct scnhdr *lit8_section;
  71 static struct scnhdr *lit4_section;
  72 static struct scnhdr *sdata_section;
  73 static struct scnhdr *sbss_section;
  74 static struct scnhdr *bss_section;
  75
  76 struct headers {
  77     struct filehdr fhdr;
  78     struct aouthdr aout;
  79     struct scnhdr section[10];
  80 };
  81
  82 /* Define name of label for entry point for the dumped executable.  */
  83
  84 #ifndef DEFAULT_ENTRY_ADDRESS
  85 #define DEFAULT_ENTRY_ADDRESS __start
  86 #endif
  87 \f
  88 unexec (new_name, a_name, data_start, bss_start, entry_address)
  89      char *new_name, *a_name;
  90      unsigned data_start, bss_start, entry_address;
  91 {
  92   int new, old;
  93   int pagesize, brk;
  94   int newsyms, symrel;
  95   int nread;
  96   struct headers hdr;
  97   int i;
  98   int vaddr, scnptr;
  99 #define BUFSIZE 8192
 100   char buffer[BUFSIZE];
 101
 102   old = open (a_name, O_RDONLY, 0);
 103   if (old < 0) fatal_unexec ("opening %s", a_name);
 104
 105   new = creat (new_name, 0666);
 106   if (new < 0) fatal_unexec ("creating %s", new_name);
 107
 108   hdr = *((struct headers *)TEXT_START);
 109 #ifdef MIPS2
 110   if (hdr.fhdr.f_magic != MIPSELMAGIC
 111       && hdr.fhdr.f_magic != MIPSEBMAGIC
 112       && hdr.fhdr.f_magic != (MIPSELMAGIC | 1)
 113       && hdr.fhdr.f_magic != (MIPSEBMAGIC | 1))
 114     {
 115       fprintf (stderr,
 116                "unexec: input file magic number is %x, not %x, %x, %x or %x.\n",
 117                hdr.fhdr.f_magic,
 118                MIPSELMAGIC, MIPSEBMAGIC,
 119                MIPSELMAGIC | 1, MIPSEBMAGIC | 1);
 120       exit(1);
 121     }
 122 #else /* not MIPS2 */
 123   if (hdr.fhdr.f_magic != MIPSELMAGIC
 124       && hdr.fhdr.f_magic != MIPSEBMAGIC)
 125     {
 126       fprintf (stderr, "unexec: input file magic number is %x, not %x or %x.\n",
 127                hdr.fhdr.f_magic, MIPSELMAGIC, MIPSEBMAGIC);
 128       exit (1);
 129     }
 130 #endif /* not MIPS2 */
 131   if (hdr.fhdr.f_opthdr != sizeof (hdr.aout))
 132     {
 133       fprintf (stderr, "unexec: input a.out header is %d bytes, not %d.\n",
 134                hdr.fhdr.f_opthdr, sizeof (hdr.aout));
 135       exit (1);
 136     }
 137   if (hdr.aout.magic != ZMAGIC)
 138     {
 139       fprintf (stderr, "unexec: input file a.out magic number is %o, not %o.\n",
 140                hdr.aout.magic, ZMAGIC);
 141       exit (1);
 142     }
 143
 144 #define CHECK_SCNHDR(ptr, name, flags)                                  \
 145   ptr = NULL;                                                           \
 146   for (i = 0; i < hdr.fhdr.f_nscns && !ptr; i++)                        \
 147     if (strcmp (hdr.section[i].s_name, name) == 0)                      \
 148       {                                                                 \
 149         if (hdr.section[i].s_flags != flags)                            \
 150           fprintf (stderr, "unexec: %x flags (%x expected) in %s section.\n", \
 151                    hdr.section[i].s_flags, flags, name);                \
 152         ptr = hdr.section + i;                                          \
 153       }                                                                 \
 154
 155   CHECK_SCNHDR (text_section,  _TEXT,  STYP_TEXT);
 156   CHECK_SCNHDR (init_section,  _INIT,  STYP_INIT);
 157   CHECK_SCNHDR (rdata_section, _RDATA, STYP_RDATA);
 158   CHECK_SCNHDR (data_section,  _DATA,  STYP_DATA);
 159 #ifdef _LIT8
 160   CHECK_SCNHDR (lit8_section,  _LIT8,  STYP_LIT8);
 161   CHECK_SCNHDR (lit4_section,  _LIT4,  STYP_LIT4);
 162 #endif /* _LIT8 */
 163   CHECK_SCNHDR (sdata_section, _SDATA, STYP_SDATA);
 164   CHECK_SCNHDR (sbss_section,  _SBSS,  STYP_SBSS);
 165   CHECK_SCNHDR (bss_section,   _BSS,   STYP_BSS);
 166 #if 0 /* Apparently this error check goes off on irix 3.3,
 167          but it doesn't indicate a real problem.  */
 168   if (i != hdr.fhdr.f_nscns)
 169     fprintf (stderr, "unexec: %d sections found instead of %d.\n",
 170              i, hdr.fhdr.f_nscns);
 171 #endif
 172
 173   text_section->s_scnptr = 0;
 174
 175   pagesize = getpagesize ();
 176   brk = (sbrk (0) + pagesize - 1) & (-pagesize);
 177   hdr.aout.dsize = brk - DATA_START;
 178   hdr.aout.bsize = 0;
 179   if (entry_address == 0)
 180     {
 181       extern DEFAULT_ENTRY_ADDRESS ();
 182       hdr.aout.entry = (unsigned)DEFAULT_ENTRY_ADDRESS;
 183     }
 184   else
 185     hdr.aout.entry = entry_address;
 186
 187   hdr.aout.bss_start = hdr.aout.data_start + hdr.aout.dsize;
 188   rdata_section->s_size = data_start - DATA_START;
 189
 190   /* Adjust start and virtual addresses of rdata_section, too.  */
 191   rdata_section->s_vaddr = DATA_START;
 192   rdata_section->s_paddr = DATA_START;
 193   rdata_section->s_scnptr = text_section->s_scnptr + hdr.aout.tsize;
 194
 195   data_section->s_vaddr = data_start;
 196   data_section->s_paddr = data_start;
 197   data_section->s_size = brk - data_start;
 198   data_section->s_scnptr = rdata_section->s_scnptr + rdata_section->s_size;
 199   vaddr = data_section->s_vaddr + data_section->s_size;
 200   scnptr = data_section->s_scnptr + data_section->s_size;
 201   if (lit8_section != NULL)
 202     {
 203       lit8_section->s_vaddr = vaddr;
 204       lit8_section->s_paddr = vaddr;
 205       lit8_section->s_size = 0;
 206       lit8_section->s_scnptr = scnptr;
 207     }
 208   if (lit4_section != NULL)
 209     {
 210       lit4_section->s_vaddr = vaddr;
 211       lit4_section->s_paddr = vaddr;
 212       lit4_section->s_size = 0;
 213       lit4_section->s_scnptr = scnptr;
 214     }
 215   if (sdata_section != NULL)
 216     {
 217       sdata_section->s_vaddr = vaddr;
 218       sdata_section->s_paddr = vaddr;
 219       sdata_section->s_size = 0;
 220       sdata_section->s_scnptr = scnptr;
 221     }
 222   if (sbss_section != NULL)
 223     {
 224       sbss_section->s_vaddr = vaddr;
 225       sbss_section->s_paddr = vaddr;
 226       sbss_section->s_size = 0;
 227       sbss_section->s_scnptr = scnptr;
 228     }
 229   if (bss_section != NULL)
 230     {
 231       bss_section->s_vaddr = vaddr;
 232       bss_section->s_paddr = vaddr;
 233       bss_section->s_size = 0;
 234       bss_section->s_scnptr = scnptr;
 235     }
 236
 237   WRITE (new, TEXT_START, hdr.aout.tsize,
 238          "writing text section to %s", new_name);
 239   WRITE (new, DATA_START, hdr.aout.dsize,
 240          "writing text section to %s", new_name);
 241
 242   SEEK (old, hdr.fhdr.f_symptr, "seeking to start of symbols in %s", a_name);
 243   errno = EEOF;
 244   nread = read (old, buffer, BUFSIZE);
 245   if (nread < sizeof (HDRR)) fatal_unexec ("reading symbols from %s", a_name);
 246 #define symhdr ((pHDRR)buffer)
 247   newsyms = hdr.aout.tsize + hdr.aout.dsize;
 248   symrel = newsyms - hdr.fhdr.f_symptr;
 249   hdr.fhdr.f_symptr = newsyms;
 250   symhdr->cbLineOffset += symrel;
 251   symhdr->cbDnOffset += symrel;
 252   symhdr->cbPdOffset += symrel;
 253   symhdr->cbSymOffset += symrel;
 254   symhdr->cbOptOffset += symrel;
 255   symhdr->cbAuxOffset += symrel;
 256   symhdr->cbSsOffset += symrel;
 257   symhdr->cbSsExtOffset += symrel;
 258   symhdr->cbFdOffset += symrel;
 259   symhdr->cbRfdOffset += symrel;
 260   symhdr->cbExtOffset += symrel;
 261 #undef symhdr
 262   do
 263     {
 264       if (write (new, buffer, nread) != nread)
 265         fatal_unexec ("writing symbols to %s", new_name);
 266       nread = read (old, buffer, BUFSIZE);
 267       if (nread < 0) fatal_unexec ("reading symbols from %s", a_name);
 268 #undef BUFSIZE
 269     } while (nread != 0);
 270
 271   SEEK (new, 0, "seeking to start of header in %s", new_name);
 272   WRITE (new, &hdr, sizeof (hdr),
 273          "writing header of %s", new_name);
 274
 275   close (old);
 276   close (new);
 277   mark_x (new_name);
 278 }
 279 \f
 280 /*
 281  * mark_x
 282  *
 283  * After successfully building the new a.out, mark it executable
 284  */
 285
 286 static void
 287 mark_x (name)
 288      char *name;
 289 {
 290   struct stat sbuf;
 291   int um = umask (777);
 292   umask (um);
 293   if (stat (name, &sbuf) < 0)
 294     fatal_unexec ("getting protection on %s", name);
 295   sbuf.st_mode |= 0111 & ~um;
 296   if (chmod (name, sbuf.st_mode) < 0)
 297     fatal_unexec ("setting protection on %s", name);
 298 }
 299
 300 static void
 301 fatal_unexec (s, va_alist)
 302     va_dcl
 303 {
 304   va_list ap;
 305   if (errno == EEOF)
 306     fputs ("unexec: unexpected end of file, ", stderr);
 307   else
 308     fprintf (stderr, "unexec: %s, ", strerror (errno));
 309   va_start (ap);
 310   _doprnt (s, ap, stderr);
 311   fputs (".\n", stderr);
 312   exit (1);
 313 }