coregrind/launcher.c

/*--------------------------------------------------------------------*/
/*--- Launching valgrind                              m_launcher.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.
*/

/* Note: this is a "normal" program and not part of Valgrind proper,
   and so it doesn't have to conform to Valgrind's arcane rules on
   no-glibc-usage etc. */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>

#include "pub_core_debuglog.h"
#include "pub_core_libcproc.h"  // For VALGRIND_LIB, VALGRIND_LAUNCHER



#define PATH_MAX 4096 /* POSIX refers to this a lot but I dunno
                         where it is defined */

static void barf ( char* str )
{
   fprintf(stderr, "valgrind: Cannot continue: %s\n", str );
   exit(1);
}

/* Where we expect to find all our aux files */
static const char *valgrind_lib = VG_LIBDIR;

int main(int argc, char** argv, char** envp)
{
   int i, j, loglevel, r;
   const char *toolname = NULL;
   const char *cp;
   char *toolfile;
   char launcher_name[PATH_MAX+1];
   char* new_line;
   char** new_env;

   /* Start the debugging-log system ASAP.  First find out how many 
      "-d"s were specified.  This is a pre-scan of the command line.
      At the same time, look for the tool name. */
   loglevel = 0;
   for (i = 1; i < argc; i++) {
      if (argv[i][0] != '-')
         break;
      if (0 == strcmp(argv[i], "--")) 
         break;
      if (0 == strcmp(argv[i], "-d")) 
         loglevel++;
      if (0 == strncmp(argv[i], "--tool=", 7)) 
         toolname = argv[i] + 7;
   }

   /* ... and start the debug logger.  Now we can safely emit logging
      messages all through startup. */
   VG_(debugLog_startup)(loglevel, "Stage 1");

   /* Make sure we know which tool we're using */
   if (toolname) {
      VG_(debugLog)(1, "launcher", "tool '%s' requested\n", toolname);
   } else {
      VG_(debugLog)(1, "launcher", 
                       "no tool requested, defaulting to 'memcheck'\n");
      toolname = "memcheck";
   }

   /* Figure out the name of this executable (viz, the launcher), so
      we can tell stage2.  stage2 will use the name for recursive
      invokations of valgrind on child processes. */
   memset(launcher_name, 0, PATH_MAX+1);
   r = readlink("/proc/self/exe", launcher_name, PATH_MAX);
   if (r == -1) {
      /* If /proc/self/exe can't be followed, don't give up.  Instead
         continue with an empty string for VALGRIND_LAUNCHER.  In the
         sys_execve wrapper, this is tested, and if found to be empty,
         fail the execve. */
      fprintf(stderr, "valgrind: warning (non-fatal): "
                      "readlink(\"/proc/self/exe\") failed.\n");
      fprintf(stderr, "valgrind: continuing, however --trace-children=yes "
                      "will not work.\n");
   }

   /* tediously augment the env: VALGRIND_LAUNCHER=launcher_name */
   new_line = malloc(strlen(VALGRIND_LAUNCHER) + 1 
                     + strlen(launcher_name) + 1);
   if (new_line == NULL)
      barf("malloc of new_line failed.");
   strcpy(new_line, VALGRIND_LAUNCHER);
   strcat(new_line, "=");
   strcat(new_line, launcher_name);

   for (j = 0; envp[j]; j++)
      ;
   new_env = malloc((j+2) * sizeof(char*));
   if (new_env == NULL)
      barf("malloc of new_env failed.");
   for (i = 0; i < j; i++)
      new_env[i] = envp[i];
   new_env[i++] = new_line;
   new_env[i++] = NULL;
   assert(i == j+2);

   /* Establish the correct VALGRIND_LIB. */
   cp = getenv(VALGRIND_LIB);

   if (cp != NULL)
      valgrind_lib = cp;

   /* Build the stage2 invokation, and execve it.  Bye! */
   toolfile = malloc(strlen(valgrind_lib) + strlen(toolname) + 2);
   if (toolfile == NULL)
      barf("malloc of toolfile failed.");
   sprintf(toolfile, "%s/%s", valgrind_lib, toolname);

   VG_(debugLog)(1, "launcher", "launching %s\n", toolfile);

   execve(toolfile, argv, new_env);

   fprintf(stderr, "valgrind: failed to start tool '%s': %s\n",
                   toolname, strerror(errno));

   exit(1);
}