coregrind/vg_procselfmaps.c

/*--------------------------------------------------------------------*/
/*--- A simple parser for /proc/self/maps on Linux 2.4.X           ---*/
/*---                                            vg_procselfmaps.c ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2000-2005 Julian Seward 
      jseward@acm.org

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
*/


#include "core.h"

/* Size of a smallish table used to read /proc/self/map entries. */
#define M_PROCMAP_BUF 50000

/* static ... to keep it out of the stack frame. */
static Char procmap_buf[M_PROCMAP_BUF];

/* Records length of /proc/self/maps read into procmap_buf. */
static Int  buf_n_tot;


/* Helper fns. */

static Int hexdigit ( Char c )
{
   if (c >= '0' && c <= '9') return (Int)(c - '0');
   if (c >= 'a' && c <= 'f') return 10 + (Int)(c - 'a');
   if (c >= 'A' && c <= 'F') return 10 + (Int)(c - 'A');
   return -1;
}

static Int decdigit ( Char c )
{
   if (c >= '0' && c <= '9') return (Int)(c - '0');
   return -1;
}

static Int readchar ( const Char* buf, Char* ch )
{
   if (*buf == 0) return 0;
   *ch = *buf;
   return 1;
}

static Int readhex ( const Char* buf, UWord* val )
{
   Int n = 0;
   *val = 0;
   while (hexdigit(*buf) >= 0) {
      *val = (*val << 4) + hexdigit(*buf);
      n++; buf++;
   }
   return n;
}

static Int readdec ( const Char* buf, UInt* val )
{
   Int n = 0;
   *val = 0;
   while (hexdigit(*buf) >= 0) {
      *val = (*val * 10) + decdigit(*buf);
      n++; buf++;
   }
   return n;
}


/* Read /proc/self/maps, store the contents into a static buffer.  If
   there's a syntax error or other failure, just abort. */

static void read_procselfmaps ( void )
{
   Int n_chunk, fd;
   
   /* Read the initial memory mapping from the /proc filesystem. */
   fd = VG_(open) ( "/proc/self/maps", VKI_O_RDONLY, 0 );
   if (fd < 0) {
      VG_(message)(Vg_UserMsg, "FATAL: can't open /proc/self/maps");
      VG_(exit)(1);
   }
   buf_n_tot = 0;
   do {
      n_chunk = VG_(read) ( fd, &procmap_buf[buf_n_tot],
                            M_PROCMAP_BUF - buf_n_tot );
      buf_n_tot += n_chunk;
   } while ( n_chunk > 0 && buf_n_tot < M_PROCMAP_BUF );
   VG_(close)(fd);
   if (buf_n_tot >= M_PROCMAP_BUF-5) {
      VG_(message)(Vg_UserMsg, "FATAL: M_PROCMAP_BUF is too small; "
                               "increase it and recompile");
       VG_(exit)(1);
   }
   if (buf_n_tot == 0) {
      VG_(message)(Vg_UserMsg, "FATAL: I/O error on /proc/self/maps" );
       VG_(exit)(1);
   }
   procmap_buf[buf_n_tot] = 0;
}

/* Parse /proc/self/maps.  For each map entry, call
   record_mapping, passing it, in this order:

      start address in memory
      length
      page protections (using the VKI_PROT_* flags)
      mapped file device and inode
      offset in file, or zero if no file
      filename, zero terminated, or NULL if no file

   So the sig of the called fn might be

      void (*record_mapping)( Addr start, SizeT size, UInt prot,
			      UInt dev, UInt info,
                              ULong foffset, UChar* filename )

   Note that the supplied filename is transiently stored; record_mapping 
   should make a copy if it wants to keep it.

   Nb: it is important that this function does not alter the contents of
       procmap_buf!
*/
void VG_(parse_procselfmaps) (
   void (*record_mapping)( Addr addr, SizeT len, UInt prot,
			   UInt dev, UInt ino, ULong foff, const UChar* filename )
   )
{
   Int    i, j, i_eol;
   Addr   start, endPlusOne;
   UChar* filename;
   UChar  rr, ww, xx, pp, ch, tmp;
   UInt	  ino, prot;
   UWord  foffset, maj, min;

   read_procselfmaps();

   tl_assert( '\0' != procmap_buf[0] && 0 != buf_n_tot);

   if (0)
      VG_(message)(Vg_DebugMsg, "raw:\n%s", procmap_buf );

   /* Ok, it's safely aboard.  Parse the entries. */
   i = 0;
   while (True) {
      if (i >= buf_n_tot) break;

      /* Read (without fscanf :) the pattern %16x-%16x %c%c%c%c %16x %2x:%2x %d */
      j = readhex(&procmap_buf[i], &start);
      if (j > 0) i += j; else goto syntaxerror;
      j = readchar(&procmap_buf[i], &ch);
      if (j == 1 && ch == '-') i += j; else goto syntaxerror;
      j = readhex(&procmap_buf[i], &endPlusOne);
      if (j > 0) i += j; else goto syntaxerror;

      j = readchar(&procmap_buf[i], &ch);
      if (j == 1 && ch == ' ') i += j; else goto syntaxerror;

      j = readchar(&procmap_buf[i], &rr);
      if (j == 1 && (rr == 'r' || rr == '-')) i += j; else goto syntaxerror;
      j = readchar(&procmap_buf[i], &ww);
      if (j == 1 && (ww == 'w' || ww == '-')) i += j; else goto syntaxerror;
      j = readchar(&procmap_buf[i], &xx);
      if (j == 1 && (xx == 'x' || xx == '-')) i += j; else goto syntaxerror;
      /* This field is the shared/private flag */
      j = readchar(&procmap_buf[i], &pp);
      if (j == 1 && (pp == 'p' || pp == '-' || pp == 's')) 
                                              i += j; else goto syntaxerror;

      j = readchar(&procmap_buf[i], &ch);
      if (j == 1 && ch == ' ') i += j; else goto syntaxerror;

      j = readhex(&procmap_buf[i], &foffset);
      if (j > 0) i += j; else goto syntaxerror;

      j = readchar(&procmap_buf[i], &ch);
      if (j == 1 && ch == ' ') i += j; else goto syntaxerror;

      j = readhex(&procmap_buf[i], &maj);
      if (j > 0) i += j; else goto syntaxerror;
      j = readchar(&procmap_buf[i], &ch);
      if (j == 1 && ch == ':') i += j; else goto syntaxerror;
      j = readhex(&procmap_buf[i], &min);
      if (j > 0) i += j; else goto syntaxerror;

      j = readchar(&procmap_buf[i], &ch);
      if (j == 1 && ch == ' ') i += j; else goto syntaxerror;

      j = readdec(&procmap_buf[i], &ino);
      if (j > 0) i += j; else goto syntaxerror;
 
      goto read_line_ok;

    syntaxerror:
      VG_(message)(Vg_UserMsg, "FATAL: syntax error reading /proc/self/maps");
      { Int k;
        VG_(printf)("last 50 chars: `");
        for (k = i-50; k <= i; k++) VG_(printf)("%c", procmap_buf[k]);
        VG_(printf)("'\n");
      }
      VG_(exit)(1);

    read_line_ok:

      /* Try and find the name of the file mapped to this segment, if
         it exists. */
      while (procmap_buf[i] != '\n' && i < buf_n_tot-1) i++;
      i_eol = i;
      i--;
      while (!VG_(isspace)(procmap_buf[i]) && i >= 0) i--;
      i++;
      if (i < i_eol-1 && procmap_buf[i] == '/') {
         /* Minor hack: put a '\0' at the filename end for the call to
            `record_mapping', then restore the old char with `tmp'. */
         filename = &procmap_buf[i];
         tmp = filename[i_eol - i];
         filename[i_eol - i] = '\0';
      } else {
	 tmp = 0;
         filename = NULL;
         foffset = 0;
      }

      prot = 0;
      if (rr == 'r') prot |= VKI_PROT_READ;
      if (ww == 'w') prot |= VKI_PROT_WRITE;
      if (xx == 'x') prot |= VKI_PROT_EXEC;

      //if (start < VG_(valgrind_last))
      (*record_mapping) ( start, endPlusOne-start, 
                          prot, maj * 256 + min, ino,
                          foffset, filename );

      if ('\0' != tmp) {
         filename[i_eol - i] = tmp;
      }

      i = i_eol + 1;
   }
}

/*--------------------------------------------------------------------*/
/*--- end                                        vg_procselfmaps.c ---*/
/*--------------------------------------------------------------------*/