2015-03-24 Paolo Carlini <paolo.carlini@oracle.com>
[official-gcc.git] / libvtv / vtv_utils.cc
blobebbeaf51999f39dd9755378a87adb33ab6fe5e98
1 /* Copyright (C) 2012-2013
2 Free Software Foundation
4 This file is part of GCC.
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.
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.
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.
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/>. */
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. */
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
42 #include <unistd.h>
43 #include <errno.h>
45 #include "vtv_utils.h"
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
55 static int vtv_failures_log_fd = -1;
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.
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.
67 int
68 __vtv_open_log (const char *name)
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;
82 logs_prefix = secure_getenv ("VTV_LOGS_DIR");
83 if (logs_prefix && strlen (logs_prefix) > 0)
85 logs_dir_specified = true;
86 #ifdef __MINGW32__
87 mkdir (logs_prefix);
88 #else
89 mkdir (logs_prefix, S_IRWXU);
90 #endif
92 snprintf (log_dir, sizeof (log_dir), "%s/vtv_logs", logs_prefix);
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
110 else
111 fd = dup (2);
113 if (fd == -1)
114 __vtv_add_to_log (2, "Cannot open log file %s %s\n", name,
115 strerror (errno));
116 return fd;
119 /* This function takes a file descriptor (FD) and a string (STR) and
120 tries to write the string to the file. */
122 static int
123 vtv_log_write (int fd, const char *str)
125 if (write (fd, str, strlen (str)) != -1)
126 return 0;
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;
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. */
142 __vtv_add_to_log (int log_file, const char * format, ...)
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];
149 va_list ap;
150 va_start (ap, format);
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);
163 return 0;
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. */
171 void
172 __vtv_log_verification_failure (const char *log_msg, bool generate_backtrace)
174 if (vtv_failures_log_fd == -1)
175 vtv_failures_log_fd = __vtv_open_log ("vtable_verification_failures.log");
177 if (vtv_failures_log_fd == -1)
178 return;
180 __vtv_add_to_log (vtv_failures_log_fd, "%s", log_msg);
182 #if !defined (__CYGWIN__) && !defined (__MINGW32__)
183 if (generate_backtrace)
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);
190 #endif