lttng/lttng.c

   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
  45 /*
  46  *  start_client
  47  *
  48  *  Process client request from the command line
  49  *  options. Every tracing action is done by the
  50  *  liblttngctl API.
  51  */
  52 static int process_client_opt(void)
  53 {
  54         int ret;
  55
  56         /* Connect to the session daemon */
  57         ret = lttng_connect_sessiond();
  58         if (ret < 0) {
  59                 ERR("%s", lttng_get_readable_code(ret));
  60                 goto end;
  61         }
  62
  63         if (opt_list_apps) {
  64                 ret = process_opt_list_apps();
  65                 if (ret < 0) {
  66                         ERR("%s", lttng_get_readable_code(ret));
  67                         goto end;
  68                 }
  69         }
  70
  71         return 0;
  72
  73 end:
  74         return ret;
  75 }
  76
  77 /*
  78  *  process_opt_list_apps
  79  *
  80  *  Get the UST traceable pid list and print
  81  *  them to the user.
  82  */
  83 static int process_opt_list_apps(void)
  84 {
  85         int i, ret;
  86         pid_t *pids;
  87         FILE *fp;
  88         char path[24];  /* Can't go bigger than /proc/65535/cmdline */
  89         char cmdline[PATH_MAX];
  90
  91         ret = lttng_ust_list_apps(&pids);
  92         if (ret < 0) {
  93                 goto error;
  94         }
  95
  96         MSG("LTTng UST traceable application [name (pid)]:");
  97         for (i=0; i < ret; i++) {
  98                 snprintf(path, sizeof(path), "/proc/%d/cmdline", pids[i]);
  99                 fp = fopen(path, "r");
 100                 if (fp == NULL) {
 101                         continue;
 102                 }
 103                 ret = fread(cmdline, 1, sizeof(cmdline), fp);
 104                 MSG("\t%s (%d)", cmdline, pids[i]);
 105                 fclose(fp);
 106         }
 107
 108         /* Allocated by lttng_ust_list_apps() */
 109         free(pids);
 110
 111         return 0;
 112
 113 error:
 114         return ret;
 115 }
 116
 117 /*
 118  *  check_ltt_sessiond
 119  *
 120  *  Check if the session daemon is available using
 121  *  the liblttngctl API for the check.
 122  */
 123 static int check_ltt_sessiond(void)
 124 {
 125         int ret;
 126
 127         ret = lttng_check_session_daemon();
 128         if (ret < 0) {
 129                 ERR("No session daemon found. Aborting.");
 130         }
 131
 132         return ret;
 133 }
 134
 135
 136 /*
 137  * clean_exit
 138  */
 139 void clean_exit(int code)
 140 {
 141         DBG("Clean exit");
 142         exit(code);
 143 }
 144
 145 /*
 146  * main
 147  */
 148 int main(int argc, char *argv[])
 149 {
 150         int ret;
 151
 152         progname = argv[0] ? argv[0] : "lttng";
 153
 154         /* For Mathieu Desnoyers aka Dr Tracing */
 155         if (strncmp(progname, "drtrace", 7) == 0) {
 156                 MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0);
 157         }
 158
 159         ret = parse_args(argc, (const char **) argv);
 160         if (ret < 0) {
 161                 return EXIT_FAILURE;
 162         }
 163
 164         if (opt_tracing_group != NULL) {
 165                 DBG("Set tracing group to '%s'", opt_tracing_group);
 166                 lttng_set_tracing_group(opt_tracing_group);
 167         }
 168
 169         /* If ask for kernel tracing, need root perms */
 170         if (opt_trace_kernel) {
 171                 DBG("Kernel tracing activated");
 172                 if (getuid() != 0) {
 173                         ERR("%s must be setuid root", progname);
 174                         return -EPERM;
 175                 }
 176         }
 177
 178         /* Check if the lttng session daemon is running.
 179          * If no, a daemon will be spawned.
 180          */
 181         if (check_ltt_sessiond() < 0) {
 182                 return EXIT_FAILURE;
 183         }
 184
 185         ret = process_client_opt();
 186         if (ret < 0) {
 187                 return ret;
 188         }
 189
 190         return 0;
 191 }