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Diffstat (limited to 'libvtv/vtv_utils.cc')
-rw-r--r-- | libvtv/vtv_utils.cc | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/libvtv/vtv_utils.cc b/libvtv/vtv_utils.cc new file mode 100644 index 00000000000..480bfa308dc --- /dev/null +++ b/libvtv/vtv_utils.cc @@ -0,0 +1,131 @@ +/* Copyright (C) 2012-2013 + Free Software Foundation + + 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> +#include <string.h> +#include <execinfo.h> +#include <unistd.h> +#include <errno.h> + +#include "vtv_utils.h" + +/* This is the directory into which all vtable verication log files + get written. */ +static const char * const logs_dir = "/tmp/vtv_logs"; +static int vtv_failures_log_fd = -1; + + + +/* 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 + decriptor. */ + +int +__vtv_open_log (const char *name) +{ + char log_name[256]; + snprintf (log_name, sizeof (log_name), "%s/%s", logs_dir, name); + mkdir (logs_dir, S_IRWXU); + int fd = open (log_name, O_WRONLY | O_APPEND | O_CREAT, S_IRWXU); + 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); + + snprintf (output, sizeof (output), "VTV: PID=%d PPID=%d ", getpid (), + getppid ()); + 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); + + 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); + } +} |