vtv_utils.cc 5.51 KB
Newer Older
1
/* Copyright (C) 2012-2017 Free Software Foundation, Inc.
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

   This file is part of GCC.

   GCC 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 3, or (at your option)
   any later version.

   GCC 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.

   Under Section 7 of GPL version 3, you are granted additional
   permissions described in the GCC Runtime Library Exception, version
   3.1, as published by the Free Software Foundation.

   You should have received a copy of the GNU General Public License and
   a copy of the GCC Runtime Library Exception along with this program;
   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
   <http://www.gnu.org/licenses/>.  */

/* This file is part of the vtable verication runtime library (see
   comments in vtv_rts.cc for more information about vtable
   verification).  This file contains log file utilities.  */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
33
#include <stdlib.h>
34
#include <string.h>
35 36 37
#if defined (__CYGWIN__) || defined (__MINGW32__)
#include <windows.h>
#else
38
#include <execinfo.h>
39 40
#endif

41 42 43 44 45
#include <unistd.h>
#include <errno.h>

#include "vtv_utils.h"

46 47 48 49 50 51 52
#ifndef HAVE_SECURE_GETENV
#  ifdef HAVE___SECURE_GETENV
#    define secure_getenv __secure_getenv
#  else
#    define secure_getenv getenv
#  endif
#endif
53

54
static int vtv_failures_log_fd = -1;
55 56 57

/* This function takes the NAME of a log file to open, attempts to
   open it in the logs_dir directory, and returns the resulting file
58 59 60 61 62 63 64
   descriptor.

   This function first checks to see if the user has specifed (via
   the environment variable VTV_LOGS_DIR) a directory to use for the
   vtable verification logs.  If that fails, the function will open
   the logs in the current directory.
*/
65 66 67 68

int
__vtv_open_log (const char *name)
{
69 70
  char log_name[1024];
  char log_dir[512];
71 72 73
#if defined (__CYGWIN__) || defined (__MINGW32__)
  pid_t process_id = GetCurrentProcessId ();
#else
74 75
  uid_t user_id = getuid ();
  pid_t process_id = getpid ();
76
#endif
77 78 79 80 81 82 83 84
  char *logs_prefix;
  bool logs_dir_specified = false;
  int fd = -1;

  logs_prefix = secure_getenv ("VTV_LOGS_DIR");
  if (logs_prefix && strlen (logs_prefix) > 0)
    {
      logs_dir_specified = true;
85 86 87
#ifdef __MINGW32__
      mkdir (logs_prefix);
#else
88
      mkdir (logs_prefix, S_IRWXU);
89 90
#endif

91 92
      snprintf (log_dir, sizeof (log_dir), "%s/vtv_logs", logs_prefix);

93 94 95 96 97 98 99 100 101 102
#ifdef __MINGW32__
      mkdir (log_dir);
#else
      mkdir (log_dir, S_IRWXU);
#endif
#if defined (__CYGWIN__) || defined (__MINGW32__)
      snprintf (log_name, sizeof (log_name), "%s_%d_%s", log_dir,
		(unsigned) process_id, name);
      fd = open (log_name, O_WRONLY | O_APPEND | O_CREAT, S_IRWXU);
#else
103 104 105 106
      snprintf (log_name, sizeof (log_name), "%s/%d_%d_%s", log_dir,
		(unsigned) user_id, (unsigned) process_id, name);
      fd = open (log_name, O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW,
		 S_IRWXU);
107
#endif
108 109 110 111
    }
  else
    fd = dup (2);

112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150
  if (fd == -1)
    __vtv_add_to_log (2, "Cannot open log file %s %s\n", name,
                    strerror (errno));
  return fd;
}

/* This function takes a file descriptor (FD) and a string (STR) and
   tries to write the string to the file.  */

static int
vtv_log_write (int fd, const char *str)
{
  if (write (fd, str, strlen (str)) != -1)
    return 0;

  if (fd != 2) /* Make sure we dont get in a loop.  */
    __vtv_add_to_log (2, "Error writing to log: %s\n", strerror (errno));
  return -1;
}


/* This function takes a file decriptor (LOG_FILE) and an output
 format string (FORMAT), followed by zero or more print format
 arguments (the same as fprintf, for example).  It gets the current
 process ID and PPID, pre-pends them to the formatted message, and
 writes write it out to the log file referenced by LOG_FILE via calles
 to vtv_log_write.  */

int
__vtv_add_to_log (int log_file, const char * format, ...)
{
  /* We dont want to dynamically allocate this buffer. This should be
     more than enough in most cases. It if isn't we are careful not to
     do a buffer overflow.  */
  char output[1024];

  va_list ap;
  va_start (ap, format);

151 152 153
#if defined (__CYGWIN__) || defined (__MINGW32__)
  snprintf (output, sizeof (output), "VTV: PID=%ld ", GetCurrentProcessId ());
#else
154 155
  snprintf (output, sizeof (output), "VTV: PID=%d PPID=%d ", getpid (),
            getppid ());
156
#endif
157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180
  vtv_log_write (log_file, output);
  vsnprintf (output, sizeof (output), format, ap);
  vtv_log_write (log_file, output);
  va_end (ap);

  return 0;
}

/* Open error logging file, if not already open, and write vtable
   verification failure messages (LOG_MSG) to the log file.  Also
   generate a backtrace in the log file, if GENERATE_BACKTRACE is
   set.  */

void
__vtv_log_verification_failure (const char *log_msg, bool generate_backtrace)
{
  if (vtv_failures_log_fd == -1)
    vtv_failures_log_fd = __vtv_open_log ("vtable_verification_failures.log");

  if (vtv_failures_log_fd == -1)
    return;

  __vtv_add_to_log (vtv_failures_log_fd, "%s", log_msg);

181
#if !defined (__CYGWIN__) && !defined (__MINGW32__)
182 183 184 185 186 187 188
  if (generate_backtrace)
    {
#define STACK_DEPTH 20
      void *callers[STACK_DEPTH];
      int actual_depth = backtrace (callers, STACK_DEPTH);
      backtrace_symbols_fd (callers, actual_depth, vtv_failures_log_fd);
    }
189
#endif
190
}