+++ /dev/null
-/*
- * lttngtrace.c
- *
- * lttngtrace starts/stop system wide tracing around program execution.
- *
- * Copyright (c) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * 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.
- *
- * This file should be setuid root, and belong to a "tracing" group. Only users
- * part of the tracing group can trace and view the traces gathered.
- *
- * TODO: LTTng should support per-session tracepoint activation.
- * TODO: use mkstemp() and save last trace name in user's home directory.
- * TODO: drop priv + reenable standard signal handlers + call lttv at the end.
- * TODO: -o option should be limited to creation of files in locations that the
- * calling user has file creation access.
- */
-
-#include <errno.h>
-#include <stdio.h>
-#include <fcntl.h>
-#include <signal.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <string.h>
-#include <limits.h>
-#include <dirent.h>
-#include <sys/wait.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
-#if DEBUG
-#define printf_dbg(fmt, args...) printf(fmt, args)
-#else
-#define printf_dbg(fmt, ...)
-#endif
-
-static char *trace_path;
-static char trace_path_pid[PATH_MAX];
-static int autotrace; /*
- * Is the trace_path automatically chosen in /tmp ? Can
- * we unlink if needed ?
- */
-static int sigfwd_pid;
-static char *progname = NULL;
-
-void usage(void) {
- fprintf(stderr, "usage : %s [-o trace_name] command\n", progname);
- fprintf(stderr, "\nTracing tool for LTTng and UST\n\
-\n\
-Options:\n\
- -o trace_name\t\tOutput file of the trace\n\
-");
-}
-
-static int recunlink(const char *dirname)
-{
- DIR *dir;
- struct dirent *entry;
- char path[PATH_MAX];
-
- dir = opendir(dirname);
- if (dir == NULL) {
- if (errno == ENOENT)
- return 0;
- perror("Error opendir()");
- return -errno;
- }
-
- while ((entry = readdir(dir)) != NULL) {
- if (strcmp(entry->d_name, ".") && strcmp(entry->d_name, "..")) {
- snprintf(path, (size_t) PATH_MAX, "%s/%s", dirname,
- entry->d_name);
- if (entry->d_type == DT_DIR)
- recunlink(path);
- else
- unlink(path);
- }
- }
- closedir(dir);
- rmdir(dirname);
-
- return 0;
-}
-
-static int start_tracing(void)
-{
- int ret;
- char command[PATH_MAX];
-
- if (autotrace) {
- ret = recunlink(trace_path);
- if (ret)
- return ret;
- }
-
- /*
- * Create the directory in /tmp to deal with races (refuse if fail).
- * Only allow user and group to read the trace data (to limit
- * information disclosure).
- */
- ret = mkdir(trace_path, S_IRWXU|S_IRWXG);
- if (ret) {
- perror("Trace directory creation error");
- return ret;
- }
- ret = system("ltt-armall > /dev/null");
- if (ret)
- return ret;
-
- ret = snprintf(command, PATH_MAX - 1,
- "lttctl -C -w %s autotrace1 > /dev/null",
- trace_path);
- ret = ret < 0 ? ret : 0;
- if (ret)
- return ret;
- ret = system(command);
- if (ret)
- return ret;
-}
-
-static int stop_tracing(uid_t uid, gid_t egid)
-{
- int ret;
-
- ret = system("lttctl -D autotrace1 > /dev/null");
- if (ret)
- return ret;
- ret = system("ltt-disarmall > /dev/null");
- if (ret)
- return ret;
- /* Hand the trace back to the user after tracing is over */
- ret = chown(trace_path, uid, egid);
- if (ret) {
- perror("chown error");
- return ret;
- }
-}
-
-static int write_child_pid(pid_t pid, uid_t uid, gid_t gid)
-{
- int fd;
- FILE *fp;
- int ret;
-
- /* Create the file as exclusive to deal with /tmp file creation races */
- fd = open(trace_path_pid, O_WRONLY | O_CREAT | O_EXCL | O_TRUNC,
- S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
- fp = fdopen(fd, "w");
- if (!fp) {
- perror("Error writing child pid");
- return -errno;
- }
-
- fprintf(fp, "%u", (unsigned int) pid);
- ret = fclose(fp);
- if (ret)
- perror("Error in fclose");
- /* Hand pid information file back to user */
- ret = chown(trace_path_pid, uid, gid);
- if (ret)
- perror("chown error");
- return ret;
-}
-
-static int parse_options(int argc, char **argv, int *arg)
-{
- int i, c;
-
- while ((c = getopt(argc, argv, "ho:")) != -1) {
- switch (c) {
- case 'o':
- trace_path = strdup(optarg);
- break;
- case 'h':
- usage();
- exit(EXIT_SUCCESS);
- case '?':
- usage();
- exit(EXIT_FAILURE);
- default:
- exit(EXIT_FAILURE);
- }
- }
-
- if (argc - optind > 0) {
- for (i = optind + 1; i < argc; i++) {
- printf ("Non-option argument %s\n", argv[i]);
- }
- } else {
- usage();
- exit(EXIT_FAILURE);
- }
-
- *arg = optind;
-
- return 0;
-}
-
-static int init_trace_path(void)
-{
- int ret;
-
- if (!trace_path) {
- trace_path = "/tmp/autotrace1";
- autotrace = 1;
- }
- ret = snprintf(trace_path_pid, PATH_MAX - 1, "%s/%s",
- trace_path, "pid");
- ret = ret < 0 ? ret : 0;
- return ret;
-}
-
-static void sighandler(int signo, siginfo_t *siginfo, void *context)
-{
- kill(sigfwd_pid, signo);
-}
-
-static int init_sighand(sigset_t *saved_mask)
-{
- sigset_t sig_all_mask;
- int gret = 0, ret;
-
- /* Block signals */
- ret = sigfillset(&sig_all_mask);
- if (ret)
- perror("Error in sigfillset");
- gret = (gret == 0) ? ret : gret;
- ret = sigprocmask(SIG_SETMASK, &sig_all_mask, saved_mask);
- if (ret)
- perror("Error in sigprocmask");
- gret = (gret == 0) ? ret : gret;
- return gret;
-}
-
-static int forward_signals(pid_t pid, sigset_t *saved_mask)
-{
- struct sigaction act;
- int gret = 0, ret;
-
- /* Forward SIGINT and SIGTERM */
- sigfwd_pid = pid;
- act.sa_sigaction = sighandler;
- act.sa_flags = SA_SIGINFO | SA_RESTART;
- sigemptyset(&act.sa_mask);
- ret = sigaction(SIGINT, &act, NULL);
- if (ret)
- perror("Error in sigaction");
- gret = (gret == 0) ? ret : gret;
- ret = sigaction(SIGTERM, &act, NULL);
- if (ret)
- perror("Error in sigaction");
- gret = (gret == 0) ? ret : gret;
-
- /* Reenable signals */
- ret = sigprocmask(SIG_SETMASK, saved_mask, NULL);
- if (ret)
- perror("Error in sigprocmask");
- gret = (gret == 0) ? ret : gret;
- return gret;
-}
-
-int main(int argc, char *argv[])
-{
- uid_t euid, uid;
- gid_t egid, gid;
- pid_t pid;
- int gret = 0, ret = 0;
- int arg = 1;
- sigset_t saved_mask;
-
- progname = argv[0];
-
- if (argc < 2) {
- usage();
- return -ENOENT;
- }
-
- euid = geteuid();
- uid = getuid();
- egid = getegid();
- gid = geteuid();
-
- if (euid != 0 && uid != 0) {
- printf("%s must be setuid root\n", progname);
- return -EPERM;
- }
-
- printf_dbg("euid: %d\n", euid);
- printf_dbg("uid: %d\n", uid);
- printf_dbg("egid: %d\n", egid);
- printf_dbg("gid: %d\n", gid);
-
- ret = parse_options(argc, argv, &arg);
- if (ret)
- return ret;
-
- ret = init_trace_path();
- gret = (gret == 0) ? ret : gret;
-
- ret = init_sighand(&saved_mask);
- gret = (gret == 0) ? ret : gret;
-
- ret = start_tracing();
- if (ret)
- return ret;
-
- pid = fork();
- if (pid > 0) { /* parent */
- int status;
-
- ret = forward_signals(pid, &saved_mask);
- gret = (gret == 0) ? ret : gret;
- pid = wait(&status);
- if (pid == -1)
- gret = (gret == 0) ? -errno : gret;
-
- ret = stop_tracing(uid, egid);
- gret = (gret == 0) ? ret : gret;
- ret = write_child_pid(pid, uid, egid);
- gret = (gret == 0) ? ret : gret;
- } else if (pid == 0) { /* child */
- /* Drop root euid before executing child program */
- seteuid(uid);
- /* Reenable signals */
- ret = sigprocmask(SIG_SETMASK, &saved_mask, NULL);
- if (ret) {
- perror("Error in sigprocmask");
- return ret;
- }
- ret = execvp(argv[arg], &argv[arg]);
- if (ret)
- perror("Execution error");
- return ret;
- } else { /* error */
- perror("Error in fork");
- return -errno;
- }
- return ret;
-}
projects / ltt-control.git / commitdiff
