coregrind/vg_preloaded.c

   1
   2 /*--------------------------------------------------------------------*/
   3 /*--- Client-space code for the core.               vg_preloaded.c ---*/
   4 /*--------------------------------------------------------------------*/
   5
   6 /*
   7    This file is part of Valgrind, a dynamic binary instrumentation
   8    framework.
   9
  10    Copyright (C) 2000-2013 Julian Seward
  11       jseward@acm.org
  12
  13    This program is free software; you can redistribute it and/or
  14    modify it under the terms of the GNU General Public License as
  15    published by the Free Software Foundation; either version 2 of the
  16    License, or (at your option) any later version.
  17
  18    This program is distributed in the hope that it will be useful, but
  19    WITHOUT ANY WARRANTY; without even the implied warranty of
  20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21    General Public License for more details.
  22
  23    You should have received a copy of the GNU General Public License
  24    along with this program; if not, write to the Free Software
  25    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  26    02111-1307, USA.
  27
  28    The GNU General Public License is contained in the file COPYING.
  29 */
  30
  31
  32 /* ---------------------------------------------------------------------
  33    ALL THE CODE IN THIS FILE RUNS ON THE SIMULATED CPU.
  34
  35    These functions are not called directly - they're the targets of code
  36    redirection or load notifications (see pub_core_redir.h for info).
  37    They're named weirdly so that the intercept code can find them when the
  38    shared object is initially loaded.
  39
  40    Note that this filename has the "vg_" prefix because it can appear
  41    in stack traces, and the "vg_" makes it a little clearer that it
  42    originates from Valgrind.
  43    ------------------------------------------------------------------ */
  44
  45 #include "pub_core_basics.h"
  46 #include "pub_core_clreq.h"
  47 #include "pub_core_debuginfo.h"  // Needed for pub_core_redir.h
  48 #include "pub_core_redir.h"      // For VG_NOTIFY_ON_LOAD
  49
  50 #if defined(VGO_linux)
  51
  52 /* ---------------------------------------------------------------------
  53    Hook for running __libc_freeres once the program exits.
  54    ------------------------------------------------------------------ */
  55
  56 void VG_NOTIFY_ON_LOAD(freeres)( void );
  57 void VG_NOTIFY_ON_LOAD(freeres)( void )
  58 {
  59 #  if !defined(__UCLIBC__) \
  60    && !defined(VGPV_arm_linux_android) && !defined(VGPV_x86_linux_android) \
  61    && !defined(VGPV_mips32_linux_android)
  62    extern void __libc_freeres(void);
  63    __libc_freeres();
  64 #  endif
  65    VALGRIND_DO_CLIENT_REQUEST_STMT(VG_USERREQ__LIBC_FREERES_DONE,
  66                                    0, 0, 0, 0, 0);
  67    /*NOTREACHED*/
  68    *(volatile int *)0 = 'x';
  69 }
  70
  71 /* ---------------------------------------------------------------------
  72    Wrapper for indirect functions which need to be redirected.
  73    ------------------------------------------------------------------ */
  74
  75 void * VG_NOTIFY_ON_LOAD(ifunc_wrapper) (void);
  76 void * VG_NOTIFY_ON_LOAD(ifunc_wrapper) (void)
  77 {
  78     OrigFn fn;
  79     Addr result = 0;
  80     Addr fnentry;
  81
  82     /* Call the original indirect function and get it's result */
  83     VALGRIND_GET_ORIG_FN(fn);
  84     CALL_FN_W_v(result, fn);
  85
  86 #if defined(VGP_ppc64be_linux)
  87    /* ppc64be uses function descriptors, so get the actual function entry
  88       address for the client request, but return the function descriptor
  89       from this function.
  90       result points to the function descriptor, which starts with the
  91       function entry. */
  92     fnentry = *(Addr*)result;
  93 #else
  94     fnentry = result;
  95 #endif
  96
  97     /* Ask the valgrind core running on the real CPU (as opposed to this
  98        code which runs on the emulated CPU) to update the redirection that
  99        led to this function. This client request eventually gives control to
 100        the function VG_(redir_add_ifunc_target) in m_redir.c  */
 101     VALGRIND_DO_CLIENT_REQUEST_STMT(VG_USERREQ__ADD_IFUNC_TARGET,
 102                                     fn.nraddr, fnentry, 0, 0, 0);
 103     return (void*)result;
 104 }
 105
 106 #elif defined(VGO_darwin)
 107
 108 #include "config.h" /* VERSION */
 109
 110 /* ---------------------------------------------------------------------
 111    Darwin crash log hints
 112    ------------------------------------------------------------------ */
 113
 114 /* This string will be inserted into crash logs, so crashes while
 115    running under Valgrind can be distinguished from other crashes. */
 116 __private_extern__ const char *__crashreporter_info__ = "Instrumented by Valgrind " VERSION;
 117
 118 /* ---------------------------------------------------------------------
 119    Darwin environment cleanup
 120    ------------------------------------------------------------------ */
 121
 122 /* Scrubbing DYLD_INSERT_LIBRARIES from envp during exec is insufficient,
 123    as there are other ways to launch a process with environment that
 124    valgrind can't catch easily (i.e. launchd).
 125    Instead, scrub DYLD_INSERT_LIBRARIES from the parent process once
 126    dyld is done loading vg_preload.so.
 127 */
 128 #include <string.h>
 129 #include <crt_externs.h>
 130
 131 // GrP fixme copied from m_libcproc
 132 static void env_unsetenv ( HChar **env, const HChar *varname )
 133 {
 134    HChar **from;
 135    HChar **to = NULL;
 136    Int len = strlen(varname);
 137
 138    for (from = to = env; from && *from; from++) {
 139       if (!(strncmp(varname, *from, len) == 0 && (*from)[len] == '=')) {
 140          *to = *from;
 141          to++;
 142       }
 143    }
 144    *(to++) = *(from++);
 145    /* fix the 4th "char* apple" pointer (aka. executable path pointer) */
 146    *(to++) = *(from++);
 147    *to = NULL;
 148 }
 149
 150 static void vg_cleanup_env(void)  __attribute__((constructor));
 151 static void vg_cleanup_env(void)
 152 {
 153     HChar **envp = (HChar**)*_NSGetEnviron();
 154     env_unsetenv(envp, "VALGRIND_LAUNCHER");
 155     env_unsetenv(envp, "DYLD_SHARED_REGION");
 156     // GrP fixme should be more like mash_colon_env()
 157     env_unsetenv(envp, "DYLD_INSERT_LIBRARIES");
 158 }
 159
 160 /* ---------------------------------------------------------------------
 161    Darwin arc4random (rdar://6166275)
 162    ------------------------------------------------------------------ */
 163
 164 #include <fcntl.h>
 165 #include <unistd.h>
 166
 167 int VG_REPLACE_FUNCTION_ZU(libSystemZdZaZddylib, arc4random)(void);
 168 int VG_REPLACE_FUNCTION_ZU(libSystemZdZaZddylib, arc4random)(void)
 169 {
 170     static int rnd = -1;
 171     int result;
 172
 173     if (rnd < 0) rnd = open("/dev/random", O_RDONLY);
 174
 175     read(rnd, &result, sizeof(result));
 176     return result;
 177 }
 178
 179 void VG_REPLACE_FUNCTION_ZU(libSystemZdZaZddylib, arc4random_stir)(void);
 180 void VG_REPLACE_FUNCTION_ZU(libSystemZdZaZddylib, arc4random_stir)(void)
 181 {
 182     // do nothing
 183 }
 184
 185 void VG_REPLACE_FUNCTION_ZU(libSystemZdZaZddylib, arc4random_addrandom)(unsigned char *dat, int datlen);
 186 void VG_REPLACE_FUNCTION_ZU(libSystemZdZaZddylib, arc4random_addrandom)(unsigned char *dat, int datlen)
 187 {
 188     // do nothing
 189     // GrP fixme ought to check [dat..dat+datlen) is defined
 190     // but don't care if it's initialized
 191 }
 192
 193 #else
 194
 195 #  error Unknown OS
 196 #endif
 197
 198 /*--------------------------------------------------------------------*/
 199 /*--- end                                                          ---*/
 200 /*--------------------------------------------------------------------*/