diff options
Diffstat (limited to 'src/Hooks/abrt-hook-ccpp.cpp')
| -rw-r--r-- | src/Hooks/abrt-hook-ccpp.cpp | 368 |
1 files changed, 368 insertions, 0 deletions
diff --git a/src/Hooks/abrt-hook-ccpp.cpp b/src/Hooks/abrt-hook-ccpp.cpp new file mode 100644 index 0000000..237ea6f --- /dev/null +++ b/src/Hooks/abrt-hook-ccpp.cpp @@ -0,0 +1,368 @@ +/* + abrt-hook-ccpp.cpp - the hook for C/C++ crashing program + + Copyright (C) 2009 Zdenek Prikryl (zprikryl@redhat.com) + Copyright (C) 2009 RedHat inc. + + This program 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 2 of the License, or + (at your option) any later version. + + This program 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. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +*/ +#include "abrtlib.h" +#include "hooklib.h" +#include "DebugDump.h" +#include "ABRTException.h" +#include <syslog.h> +#include <sys/statvfs.h> + +#define FILENAME_EXECUTABLE "executable" +#define FILENAME_COREDUMP "coredump" + +using namespace std; + +static char* malloc_readlink(const char *linkname) +{ + char buf[PATH_MAX + 1]; + int len; + + len = readlink(linkname, buf, sizeof(buf)-1); + if (len >= 0) + { + buf[len] = '\0'; + return xstrdup(buf); + } + return NULL; +} + +static char* get_executable(pid_t pid) +{ + char buf[sizeof("/proc/%lu/exe") + sizeof(long)*3]; + + sprintf(buf, "/proc/%lu/exe", (long)pid); + return malloc_readlink(buf); +} + +static char* get_cwd(pid_t pid) +{ + char buf[sizeof("/proc/%lu/cwd") + sizeof(long)*3]; + + sprintf(buf, "/proc/%lu/cwd", (long)pid); + return malloc_readlink(buf); +} + +int main(int argc, char** argv) +{ + int fd; + struct stat sb; + + if (argc < 5) + { + const char* program_name = argv[0]; + error_msg_and_die("Usage: %s: DUMPDIR PID SIGNO UID CORE_SIZE_LIMIT", program_name); + } + openlog("abrt", 0, LOG_PID | LOG_DAEMON); + logmode = LOGMODE_SYSLOG; + + errno = 0; + const char* dddir = argv[1]; + pid_t pid = xatoi_u(argv[2]); + const char* signal_str = argv[3]; + int signal_no = xatoi_u(argv[3]); + uid_t uid = xatoi_u(argv[4]); + off_t ulimit_c = strtoull(argv[5], NULL, 10); + off_t core_size = 0; + + if (errno || pid <= 0 || ulimit_c < 0) + { + error_msg_and_die("pid '%s' or limit '%s' is bogus", argv[2], argv[5]); + } + if (signal_no != SIGQUIT + && signal_no != SIGILL + && signal_no != SIGABRT + && signal_no != SIGFPE + && signal_no != SIGSEGV + ) { + /* not an error, exit silently */ + return 0; + } + + + char *user_pwd = get_cwd(pid); /* may be NULL on error */ + int core_fd = STDIN_FILENO; + + if (!daemon_is_ok()) + { + /* not an error, exit with exitcode 0 */ + log("abrt daemon is not running. If it crashed, " + "/proc/sys/kernel/core_pattern contains a stale value, " + "consider resetting it to 'core'" + ); + goto create_user_core; + } + + try + { + char* executable = get_executable(pid); + if (executable == NULL) + { + error_msg_and_die("can't read /proc/%lu/exe link", (long)pid); + } + if (strstr(executable, "/abrt-hook-ccpp")) + { + error_msg_and_die("pid %lu is '%s', not dumping it to avoid recursion", + (long)pid, executable); + } + + /* Parse abrt.conf and plugins/CCpp.conf */ + unsigned setting_MaxCrashReportsSize = 0; + bool setting_MakeCompatCore = false; + parse_conf(CONF_DIR"/plugins/CCpp.conf", &setting_MaxCrashReportsSize, &setting_MakeCompatCore); + + if (setting_MaxCrashReportsSize > 0) + { + check_free_space(setting_MaxCrashReportsSize); + } + + char path[PATH_MAX]; + + /* Check /var/cache/abrt/last-ccpp marker, do not dump repeated crashes + * if they happen too often. Else, write new marker value. + */ + snprintf(path, sizeof(path), "%s/last-ccpp", dddir); + fd = open(path, O_RDWR | O_CREAT, 0600); + if (fd >= 0) + { + int sz; + fstat(fd, &sb); /* !paranoia. this can't fail. */ + + if (sb.st_size != 0 /* if it wasn't created by us just now... */ + && (unsigned)(time(NULL) - sb.st_mtime) < 20 /* and is relatively new [is 20 sec ok?] */ + ) { + sz = read(fd, path, sizeof(path)-1); /* (ab)using path as scratch buf */ + if (sz > 0) + { + path[sz] = '\0'; + if (strcmp(executable, path) == 0) + { + error_msg("not dumping repeating crash in '%s'", executable); + if (setting_MakeCompatCore) + goto create_user_core; + return 1; + } + } + lseek(fd, 0, SEEK_SET); + } + sz = write(fd, executable, strlen(executable)); + if (sz >= 0) + ftruncate(fd, sz); + close(fd); + } + + if (strstr(executable, "/abrtd")) + { + /* If abrtd crashes, we don't want to create a _directory_, + * since that can make new copy of abrtd to process it, + * and maybe crash again... + * Unlike dirs, mere files are ignored by abrtd. + */ + snprintf(path, sizeof(path), "%s/abrtd-coredump", dddir); + core_fd = xopen3(path, O_WRONLY | O_CREAT | O_TRUNC, 0644); + core_size = copyfd_eof(STDIN_FILENO, core_fd); + if (core_size < 0 || close(core_fd) != 0) + { + unlink(path); + /* copyfd_eof logs the error including errno string, + * but it does not log file name */ + error_msg_and_die("error saving coredump to %s", path); + } + log("saved core dump of pid %lu (%s) to %s (%llu bytes)", (long)pid, executable, path, (long long)core_size); + return 0; + } + + char* cmdline = get_cmdline(pid); /* never NULL */ + const char *signame = strsignal(signal_no); + char *reason = xasprintf("Process was terminated by signal %s (%s)", signal_str, signame ? signame : signal_str); + + snprintf(path, sizeof(path), "%s/ccpp-%ld-%lu", dddir, (long)time(NULL), (long)pid); + CDebugDump dd; + dd.Create(path, uid); + dd.SaveText(FILENAME_ANALYZER, "CCpp"); + dd.SaveText(FILENAME_EXECUTABLE, executable); + dd.SaveText(FILENAME_CMDLINE, cmdline); + dd.SaveText(FILENAME_REASON, reason); + + int len = strlen(path); + snprintf(path + len, sizeof(path) - len, "/"FILENAME_COREDUMP); + + /* We need coredumps to be readable by all, because + * when abrt daemon processes coredump, + * process producing backtrace is run under the same UID + * as the crashed process. + * Thus 644, not 600 */ + core_fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0644); + if (core_fd < 0) + { + dd.Delete(); + dd.Close(); + perror_msg_and_die("can't open '%s'", path); + } +//TODO: chown to uid:abrt? +//Currently it is owned by 0:0 but is readable by anyone, so the owner +//of the crashed binary still can access it, as he has +//r-x access to the dump dir. + core_size = copyfd_eof(STDIN_FILENO, core_fd); + if (core_size < 0 || fsync(core_fd) != 0) + { + unlink(path); + dd.Delete(); + dd.Close(); + /* copyfd_eof logs the error including errno string, + * but it does not log file name */ + error_msg_and_die("error saving coredump to %s", path); + } + lseek(core_fd, 0, SEEK_SET); + /* note: core_fd is still open, we may use it later to copy core to user's dir */ + log("saved core dump of pid %lu (%s) to %s (%llu bytes)", (long)pid, executable, path, (long long)core_size); + free(executable); + free(cmdline); + path[len] = '\0'; /* path now contains directory name */ + + /* We close dumpdir before we start catering for crash storm case. + * Otherwise, delete_debug_dump_dir's from other concurrent + * CCpp's won't be able to delete our dump (their delete_debug_dump_dir + * will wait for us), and we won't be able to delete their dumps. + * Classic deadlock. + */ + dd.Close(); + + /* rhbz#539551: "abrt going crazy when crashing process is respawned" */ + if (setting_MaxCrashReportsSize > 0) + { + trim_debug_dumps(setting_MaxCrashReportsSize, path); + } + + if (!setting_MakeCompatCore) + return 0; + /* fall through to creating user core */ + } + catch (CABRTException& e) + { + error_msg_and_die("%s", e.what()); + } + catch (std::exception& e) + { + error_msg_and_die("%s", e.what()); + } + + + create_user_core: + /* note: core_size may be == 0 ("unknown") */ + if (core_size > ulimit_c || ulimit_c == 0) + return 0; + + /* Write a core file for user */ + + struct passwd* pw = getpwuid(uid); + gid_t gid = pw ? pw->pw_gid : uid; + setgroups(1, &gid); + xsetregid(gid, gid); + xsetreuid(uid, uid); + + errno = 0; + if (user_pwd == NULL + || chdir(user_pwd) != 0 + ) { + perror_msg_and_die("can't cd to %s", user_pwd); + } + + /* Mimic "core.PID" if requested */ + char core_basename[sizeof("core.%lu") + sizeof(long)*3] = "core"; + char buf[] = "0\n"; + fd = open("/proc/sys/kernel/core_uses_pid", O_RDONLY); + if (fd >= 0) + { + read(fd, buf, sizeof(buf)); + close(fd); + } + if (strcmp(buf, "1\n") == 0) + { + sprintf(core_basename, "core.%lu", (long)pid); + } + + /* man core: + * There are various circumstances in which a core dump file + * is not produced: + * + * [skipped obvious ones] + * The process does not have permission to write the core file. + * ...if a file with the same name exists and is not writable + * or is not a regular file (e.g., it is a directory or a symbolic link). + * + * A file with the same name already exists, but there is more + * than one hard link to that file. + * + * The file system where the core dump file would be created is full; + * or has run out of inodes; or is mounted read-only; + * or the user has reached their quota for the file system. + * + * The RLIMIT_CORE or RLIMIT_FSIZE resource limits for the process + * are set to zero. + * [shouldn't it be checked by kernel? 2.6.30.9-96 doesn't, still + * calls us even if "ulimit -c 0"] + * + * The binary being executed by the process does not have + * read permission enabled. [how we can check it here?] + * + * The process is executing a set-user-ID (set-group-ID) program + * that is owned by a user (group) other than the real + * user (group) ID of the process. [TODO?] + * (However, see the description of the prctl(2) PR_SET_DUMPABLE operation, + * and the description of the /proc/sys/fs/suid_dumpable file in proc(5).) + */ + + /* Do not O_TRUNC: if later checks fail, we do not want to have file already modified here */ + errno = 0; + int usercore_fd = open(core_basename, O_WRONLY | O_CREAT | O_NOFOLLOW, 0600); /* kernel makes 0600 too */ + if (usercore_fd < 0 + || fstat(usercore_fd, &sb) != 0 + || !S_ISREG(sb.st_mode) + || sb.st_nlink != 1 + /* kernel internal dumper checks this too: if (inode->i_uid != current->fsuid) <fail>, need to mimic? */ + ) { + perror_msg_and_die("%s/%s is not a regular file with link count 1", user_pwd, core_basename); + } + + /* Note: we do not copy more than ulimit_c */ + off_t size; + if (ftruncate(usercore_fd, 0) != 0 + || (size = copyfd_size(core_fd, usercore_fd, ulimit_c)) < 0 + || close(usercore_fd) != 0 + ) { + /* perror first, otherwise unlink may trash errno */ + perror_msg("write error writing %s/%s", user_pwd, core_basename); + unlink(core_basename); + return 1; + } + if (size == ulimit_c && size != core_size) + { + /* We copied exactly ulimit_c bytes (and it doesn't accidentally match + * core_size (imagine exactly 1MB coredump with "ulimit -c 1M" - that'd be ok)), + * it means that core is larger than ulimit_c. Abort and delete the dump. + */ + unlink(core_basename); + return 1; + } + log("saved core dump of pid %lu to %s/%s (%llu bytes)", (long)pid, user_pwd, core_basename, (long long)size); + + return 0; +} |