| 1 | /* |
| 2 | * Copyright (c) 2011 David Goulet <david.goulet@polymtl.ca> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License along |
| 15 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 16 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 17 | */ |
| 18 | |
| 19 | #define _GNU_SOURCE |
| 20 | #include <errno.h> |
| 21 | #include <fcntl.h> |
| 22 | #include <getopt.h> |
| 23 | #include <grp.h> |
| 24 | #include <limits.h> |
| 25 | #include <stdio.h> |
| 26 | #include <stdlib.h> |
| 27 | #include <string.h> |
| 28 | #include <sys/stat.h> |
| 29 | #include <sys/types.h> |
| 30 | #include <sys/wait.h> |
| 31 | #include <unistd.h> |
| 32 | |
| 33 | #include <lttng/liblttngctl.h> |
| 34 | |
| 35 | #include "lttng.h" |
| 36 | #include "lttngerr.h" |
| 37 | |
| 38 | /* Variables */ |
| 39 | static char *progname; |
| 40 | |
| 41 | /* Prototypes */ |
| 42 | static int process_client_opt(void); |
| 43 | static int process_opt_list_apps(void); |
| 44 | static void sighandler(int sig); |
| 45 | static int set_signal_handler(void); |
| 46 | |
| 47 | /* |
| 48 | * start_client |
| 49 | * |
| 50 | * Process client request from the command line |
| 51 | * options. Every tracing action is done by the |
| 52 | * liblttngctl API. |
| 53 | */ |
| 54 | static int process_client_opt(void) |
| 55 | { |
| 56 | int ret; |
| 57 | |
| 58 | /* Connect to the session daemon */ |
| 59 | ret = lttng_connect_sessiond(); |
| 60 | if (ret < 0) { |
| 61 | goto end; |
| 62 | } |
| 63 | |
| 64 | if (opt_list_apps) { |
| 65 | ret = process_opt_list_apps(); |
| 66 | if (ret < 0) { |
| 67 | goto end; |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | return 0; |
| 72 | |
| 73 | end: |
| 74 | ERR("%s", lttng_get_readable_code(ret)); |
| 75 | return ret; |
| 76 | } |
| 77 | |
| 78 | /* |
| 79 | * process_opt_list_apps |
| 80 | * |
| 81 | * Get the UST traceable pid list and print |
| 82 | * them to the user. |
| 83 | */ |
| 84 | static int process_opt_list_apps(void) |
| 85 | { |
| 86 | int i, ret; |
| 87 | pid_t *pids; |
| 88 | FILE *fp; |
| 89 | char path[24]; /* Can't go bigger than /proc/65535/cmdline */ |
| 90 | char cmdline[PATH_MAX]; |
| 91 | |
| 92 | ret = lttng_ust_list_apps(&pids); |
| 93 | if (ret < 0) { |
| 94 | goto error; |
| 95 | } |
| 96 | |
| 97 | MSG("LTTng UST traceable application [name (pid)]:"); |
| 98 | for (i=0; i < ret; i++) { |
| 99 | snprintf(path, sizeof(path), "/proc/%d/cmdline", pids[i]); |
| 100 | fp = fopen(path, "r"); |
| 101 | if (fp == NULL) { |
| 102 | continue; |
| 103 | } |
| 104 | ret = fread(cmdline, 1, sizeof(cmdline), fp); |
| 105 | MSG("\t%s (%d)", cmdline, pids[i]); |
| 106 | fclose(fp); |
| 107 | } |
| 108 | |
| 109 | /* Allocated by lttng_ust_list_apps() */ |
| 110 | free(pids); |
| 111 | |
| 112 | return 0; |
| 113 | |
| 114 | error: |
| 115 | return ret; |
| 116 | } |
| 117 | |
| 118 | /* |
| 119 | * spawn_sessiond |
| 120 | * |
| 121 | * Spawn a session daemon by forking and execv. |
| 122 | */ |
| 123 | static int spawn_sessiond(char *pathname) |
| 124 | { |
| 125 | int ret = 0; |
| 126 | pid_t pid; |
| 127 | |
| 128 | MSG("Spawning session daemon"); |
| 129 | pid = fork(); |
| 130 | if (pid == 0) { |
| 131 | /* Spawn session daemon and tell |
| 132 | * it to signal us when ready. |
| 133 | */ |
| 134 | ret = execlp(pathname, "ltt-sessiond", "--sig-parent", NULL); |
| 135 | if (ret < 0) { |
| 136 | if (errno == ENOENT) { |
| 137 | ERR("No session daemon found. Use --sessiond-path."); |
| 138 | } else { |
| 139 | perror("execlp"); |
| 140 | } |
| 141 | kill(getppid(), SIGTERM); |
| 142 | exit(EXIT_FAILURE); |
| 143 | } |
| 144 | exit(EXIT_SUCCESS); |
| 145 | } else if (pid > 0) { |
| 146 | /* Wait for ltt-sessiond to start */ |
| 147 | pause(); |
| 148 | goto end; |
| 149 | } else { |
| 150 | perror("fork"); |
| 151 | ret = -1; |
| 152 | goto end; |
| 153 | } |
| 154 | |
| 155 | end: |
| 156 | return ret; |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * check_ltt_sessiond |
| 161 | * |
| 162 | * Check if the session daemon is available using |
| 163 | * the liblttngctl API for the check. If not, try to |
| 164 | * spawn a daemon. |
| 165 | */ |
| 166 | static int check_ltt_sessiond(void) |
| 167 | { |
| 168 | int ret; |
| 169 | char *pathname = NULL; |
| 170 | |
| 171 | ret = lttng_check_session_daemon(); |
| 172 | if (ret < 0) { |
| 173 | /* Try command line option path */ |
| 174 | if (opt_sessiond_path != NULL) { |
| 175 | ret = access(opt_sessiond_path, F_OK | X_OK); |
| 176 | if (ret < 0) { |
| 177 | ERR("No such file: %s", opt_sessiond_path); |
| 178 | goto end; |
| 179 | } |
| 180 | pathname = opt_sessiond_path; |
| 181 | } else { |
| 182 | /* Try LTTNG_SESSIOND_PATH env variable */ |
| 183 | pathname = strdup(getenv(LTTNG_SESSIOND_PATH_ENV)); |
| 184 | } |
| 185 | |
| 186 | /* Let's rock and roll */ |
| 187 | if (pathname == NULL) { |
| 188 | ret = asprintf(&pathname, "ltt-sessiond"); |
| 189 | if (ret < 0) { |
| 190 | goto end; |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | ret = spawn_sessiond(pathname); |
| 195 | free(pathname); |
| 196 | if (ret < 0) { |
| 197 | ERR("Problem occurs when starting %s", pathname); |
| 198 | goto end; |
| 199 | } |
| 200 | } |
| 201 | |
| 202 | end: |
| 203 | return ret; |
| 204 | } |
| 205 | |
| 206 | /* |
| 207 | * set_signal_handler |
| 208 | * |
| 209 | * Setup signal handler for SIGCHLD and SIGTERM. |
| 210 | */ |
| 211 | static int set_signal_handler(void) |
| 212 | { |
| 213 | int ret = 0; |
| 214 | struct sigaction sa; |
| 215 | sigset_t sigset; |
| 216 | |
| 217 | if ((ret = sigemptyset(&sigset)) < 0) { |
| 218 | perror("sigemptyset"); |
| 219 | goto end; |
| 220 | } |
| 221 | |
| 222 | sa.sa_handler = sighandler; |
| 223 | sa.sa_mask = sigset; |
| 224 | sa.sa_flags = 0; |
| 225 | if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) { |
| 226 | perror("sigaction"); |
| 227 | goto end; |
| 228 | } |
| 229 | |
| 230 | if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) { |
| 231 | perror("sigaction"); |
| 232 | goto end; |
| 233 | } |
| 234 | |
| 235 | end: |
| 236 | return ret; |
| 237 | } |
| 238 | |
| 239 | /* |
| 240 | * sighandler |
| 241 | * |
| 242 | * Signal handler for the daemon |
| 243 | */ |
| 244 | static void sighandler(int sig) |
| 245 | { |
| 246 | DBG("%d received", sig); |
| 247 | switch (sig) { |
| 248 | case SIGTERM: |
| 249 | clean_exit(EXIT_FAILURE); |
| 250 | break; |
| 251 | case SIGCHLD: |
| 252 | /* Notify is done */ |
| 253 | break; |
| 254 | default: |
| 255 | break; |
| 256 | } |
| 257 | |
| 258 | return; |
| 259 | } |
| 260 | /* |
| 261 | * clean_exit |
| 262 | */ |
| 263 | void clean_exit(int code) |
| 264 | { |
| 265 | DBG("Clean exit"); |
| 266 | exit(code); |
| 267 | } |
| 268 | |
| 269 | /* |
| 270 | * main |
| 271 | */ |
| 272 | int main(int argc, char *argv[]) |
| 273 | { |
| 274 | int ret; |
| 275 | |
| 276 | progname = argv[0] ? argv[0] : "lttng"; |
| 277 | |
| 278 | /* For Mathieu Desnoyers aka Dr Tracing */ |
| 279 | if (strncmp(progname, "drtrace", 7) == 0) { |
| 280 | MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0); |
| 281 | } |
| 282 | |
| 283 | ret = parse_args(argc, (const char **) argv); |
| 284 | if (ret < 0) { |
| 285 | return EXIT_FAILURE; |
| 286 | } |
| 287 | |
| 288 | ret = set_signal_handler(); |
| 289 | if (ret < 0) { |
| 290 | return ret; |
| 291 | } |
| 292 | |
| 293 | if (opt_tracing_group != NULL) { |
| 294 | DBG("Set tracing group to '%s'", opt_tracing_group); |
| 295 | lttng_set_tracing_group(opt_tracing_group); |
| 296 | } |
| 297 | |
| 298 | /* If ask for kernel tracing, need root perms */ |
| 299 | if (opt_trace_kernel) { |
| 300 | DBG("Kernel tracing activated"); |
| 301 | if (getuid() != 0) { |
| 302 | ERR("%s must be setuid root", progname); |
| 303 | return -EPERM; |
| 304 | } |
| 305 | } |
| 306 | |
| 307 | /* Check if the lttng session daemon is running. |
| 308 | * If no, a daemon will be spawned. |
| 309 | */ |
| 310 | if (opt_no_sessiond == 0 && (check_ltt_sessiond() < 0)) { |
| 311 | return EXIT_FAILURE; |
| 312 | } |
| 313 | |
| 314 | ret = process_client_opt(); |
| 315 | if (ret < 0) { |
| 316 | return ret; |
| 317 | } |
| 318 | |
| 319 | return 0; |
| 320 | } |