lttng/lttng.c

   1 /* Copyright (c)  2011 David Goulet <david.goulet@polymtl.ca>
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  *
  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         return 0;
 109
 110 error:
 111         return ret;
 112 }
 113
 114 /*
 115  *  check_ltt_sessiond
 116  *
 117  *  Check if the session daemon is available using
 118  *  the liblttngctl API for the check.
 119  */
 120 static int check_ltt_sessiond(void)
 121 {
 122         int ret;
 123
 124         ret = lttng_check_session_daemon();
 125         if (ret < 0) {
 126                 ERR("No session daemon found. Aborting.");
 127         }
 128
 129         return ret;
 130 }
 131
 132
 133 /*
 134  * clean_exit
 135  */
 136 void clean_exit(int code)
 137 {
 138         DBG("Clean exit");
 139         exit(code);
 140 }
 141
 142 /*
 143  * main
 144  */
 145 int main(int argc, char *argv[])
 146 {
 147         int ret;
 148
 149         progname = argv[0] ? argv[0] : "lttng";
 150
 151         /* For Mathieu Desnoyers aka Dr Tracing */
 152         if (strncmp(progname, "drtrace", 7) == 0) {
 153                 MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0);
 154         }
 155
 156         ret = parse_args(argc, (const char **) argv);
 157         if (ret < 0) {
 158                 return EXIT_FAILURE;
 159         }
 160
 161         if (opt_tracing_group != NULL) {
 162                 DBG("Set tracing group to '%s'", opt_tracing_group);
 163                 lttng_set_tracing_group(opt_tracing_group);
 164         }
 165
 166         /* If ask for kernel tracing, need root perms */
 167         if (opt_trace_kernel) {
 168                 DBG("Kernel tracing activated");
 169                 if (getuid() != 0) {
 170                         ERR("%s must be setuid root", progname);
 171                         return -EPERM;
 172                 }
 173         }
 174
 175         /* Check if the lttng session daemon is running.
 176          * If no, a daemon will be spawned.
 177          */
 178         if (check_ltt_sessiond() < 0) {
 179                 return EXIT_FAILURE;
 180         }
 181
 182         ret = process_client_opt();
 183         if (ret < 0) {
 184                 return ret;
 185         }
 186
 187         return 0;
 188 }