1/* Copyright (C) 2012-2013 2 Free Software Foundation 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GCC is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 <http://www.gnu.org/licenses/>. */ 24 25/* This file is part of the vtable verication runtime library (see 26 comments in vtv_rts.cc for more information about vtable 27 verification). This file contains log file utilities. */ 28 29#include <sys/types.h> 30#include <sys/stat.h> 31#include <fcntl.h> 32#include <stdarg.h> 33#include <stdio.h> 34#include <stdlib.h> 35#include <string.h> 36#if defined (__CYGWIN__) || defined (__MINGW32__) 37#include <windows.h> 38#else 39#include <execinfo.h> 40#endif 41 42#include <unistd.h> 43#include <errno.h> 44 45#include "vtv_utils.h" 46 47#ifndef HAVE_SECURE_GETENV 48# ifdef HAVE___SECURE_GETENV 49# define secure_getenv __secure_getenv 50# else 51# define secure_getenv getenv 52# endif 53#endif 54 55static int vtv_failures_log_fd = -1; 56 57/* This function takes the NAME of a log file to open, attempts to 58 open it in the logs_dir directory, and returns the resulting file 59 descriptor. 60 61 This function first checks to see if the user has specifed (via 62 the environment variable VTV_LOGS_DIR) a directory to use for the 63 vtable verification logs. If that fails, the function will open 64 the logs in the current directory. 65*/ 66 67int 68__vtv_open_log (const char *name) 69{ 70 char log_name[1024]; 71 char log_dir[512]; 72#if defined (__CYGWIN__) || defined (__MINGW32__) 73 pid_t process_id = GetCurrentProcessId (); 74#else 75 uid_t user_id = getuid (); 76 pid_t process_id = getpid (); 77#endif 78 char *logs_prefix; 79 bool logs_dir_specified = false; 80 int fd = -1; 81 82 logs_prefix = secure_getenv ("VTV_LOGS_DIR"); 83 if (logs_prefix && strlen (logs_prefix) > 0) 84 { 85 logs_dir_specified = true; 86#ifdef __MINGW32__ 87 mkdir (logs_prefix); 88#else 89 mkdir (logs_prefix, S_IRWXU); 90#endif 91 92 snprintf (log_dir, sizeof (log_dir), "%s/vtv_logs", logs_prefix); 93 94#ifdef __MINGW32__ 95 mkdir (log_dir); 96#else 97 mkdir (log_dir, S_IRWXU); 98#endif 99#if defined (__CYGWIN__) || defined (__MINGW32__) 100 snprintf (log_name, sizeof (log_name), "%s_%d_%s", log_dir, 101 (unsigned) process_id, name); 102 fd = open (log_name, O_WRONLY | O_APPEND | O_CREAT, S_IRWXU); 103#else 104 snprintf (log_name, sizeof (log_name), "%s/%d_%d_%s", log_dir, 105 (unsigned) user_id, (unsigned) process_id, name); 106 fd = open (log_name, O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW, 107 S_IRWXU); 108#endif 109 } 110 else 111 fd = dup (2); 112 113 if (fd == -1) 114 __vtv_add_to_log (2, "Cannot open log file %s %s\n", name, 115 strerror (errno)); 116 return fd; 117} 118 119/* This function takes a file descriptor (FD) and a string (STR) and 120 tries to write the string to the file. */ 121 122static int 123vtv_log_write (int fd, const char *str) 124{ 125 if (write (fd, str, strlen (str)) != -1) 126 return 0; 127 128 if (fd != 2) /* Make sure we dont get in a loop. */ 129 __vtv_add_to_log (2, "Error writing to log: %s\n", strerror (errno)); 130 return -1; 131} 132 133 134/* This function takes a file decriptor (LOG_FILE) and an output 135 format string (FORMAT), followed by zero or more print format 136 arguments (the same as fprintf, for example). It gets the current 137 process ID and PPID, pre-pends them to the formatted message, and 138 writes write it out to the log file referenced by LOG_FILE via calles 139 to vtv_log_write. */ 140 141int 142__vtv_add_to_log (int log_file, const char * format, ...) 143{ 144 /* We dont want to dynamically allocate this buffer. This should be 145 more than enough in most cases. It if isn't we are careful not to 146 do a buffer overflow. */ 147 char output[1024]; 148 149 va_list ap; 150 va_start (ap, format); 151 152#if defined (__CYGWIN__) || defined (__MINGW32__) 153 snprintf (output, sizeof (output), "VTV: PID=%ld ", GetCurrentProcessId ()); 154#else 155 snprintf (output, sizeof (output), "VTV: PID=%d PPID=%d ", getpid (), 156 getppid ()); 157#endif 158 vtv_log_write (log_file, output); 159 vsnprintf (output, sizeof (output), format, ap); 160 vtv_log_write (log_file, output); 161 va_end (ap); 162 163 return 0; 164} 165 166/* Open error logging file, if not already open, and write vtable 167 verification failure messages (LOG_MSG) to the log file. Also 168 generate a backtrace in the log file, if GENERATE_BACKTRACE is 169 set. */ 170 171void 172__vtv_log_verification_failure (const char *log_msg, bool generate_backtrace) 173{ 174 if (vtv_failures_log_fd == -1) 175 vtv_failures_log_fd = __vtv_open_log ("vtable_verification_failures.log"); 176 177 if (vtv_failures_log_fd == -1) 178 return; 179 180 __vtv_add_to_log (vtv_failures_log_fd, "%s", log_msg); 181 182#if !defined (__CYGWIN__) && !defined (__MINGW32__) 183 if (generate_backtrace) 184 { 185#define STACK_DEPTH 20 186 void *callers[STACK_DEPTH]; 187 int actual_depth = backtrace (callers, STACK_DEPTH); 188 backtrace_symbols_fd (callers, actual_depth, vtv_failures_log_fd); 189 } 190#endif 191} 192