src/bin/lttng/commands/view.cpp

   1 /*
   2  * Copyright (C) 2011 David Goulet <dgoulet@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <popt.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include <unistd.h>
  16
  17 #include <common/spawn-viewer.hpp>
  18 #include "../command.hpp"
  19
  20 static char *opt_session_name;
  21 static char *opt_viewer;
  22 static char *opt_trace_path;
  23
  24 #ifdef LTTNG_EMBED_HELP
  25 static const char help_msg[] =
  26 #include <lttng-view.1.h>
  27 ;
  28 #endif
  29
  30 enum {
  31         OPT_HELP = 1,
  32         OPT_LIST_OPTIONS,
  33 };
  34
  35 static struct poptOption long_options[] = {
  36         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  37         {"help",        'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  38         {"list-options", 0,  POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  39         {"viewer",      'e', POPT_ARG_STRING, &opt_viewer, 0, 0, 0},
  40         {"trace-path",  't', POPT_ARG_STRING, &opt_trace_path, 0, 0, 0},
  41         {0, 0, 0, 0, 0, 0, 0}
  42 };
  43
  44 /* Is the session we are trying to view is in live mode. */
  45 static int session_live_mode;
  46
  47 /*
  48  * Build the live path we need for the lttng live view.
  49  */
  50 static char *build_live_path(char *session_name)
  51 {
  52         int ret;
  53         char *path = NULL;
  54         char hostname[LTTNG_HOST_NAME_MAX];
  55
  56         ret = gethostname(hostname, sizeof(hostname));
  57         if (ret < 0) {
  58                 PERROR("gethostname");
  59                 goto error;
  60         }
  61
  62         ret = asprintf(&path, "net://localhost/host/%s/%s", hostname,
  63                         session_name);
  64         if (ret < 0) {
  65                 PERROR("asprintf live path");
  66                 goto error;
  67         }
  68
  69 error:
  70         return path;
  71 }
  72
  73 /*
  74  * Exec viewer if found and use session name path.
  75  */
  76 static int view_trace(void)
  77 {
  78         int ret;
  79         char *session_name, *trace_path = NULL;
  80         struct lttng_session *sessions = NULL;
  81         bool free_trace_path = false;
  82
  83         /*
  84          * Safety net. If lttng is suid at some point for *any* useless reasons,
  85          * this prevent any bad execution of binaries.
  86          */
  87         if (getuid() != 0) {
  88                 if (getuid() != geteuid()) {
  89                         ERR("UID does not match effective UID.");
  90                         ret = CMD_ERROR;
  91                         goto error;
  92                 } else if (getgid() != getegid()) {
  93                         ERR("GID does not match effective GID.");
  94                         ret = CMD_ERROR;
  95                         goto error;
  96                 }
  97         }
  98
  99         /* User define trace path override the session name */
 100         if (opt_trace_path) {
 101                 session_name = NULL;
 102         } else if(opt_session_name == NULL) {
 103                 session_name = get_session_name();
 104                 if (session_name == NULL) {
 105                         ret = CMD_ERROR;
 106                         goto error;
 107                 }
 108         } else {
 109                 session_name = opt_session_name;
 110         }
 111
 112         DBG("Viewing trace for session %s", session_name);
 113
 114         if (session_name) {
 115                 int i, count, found = 0;
 116
 117                 /* Getting all sessions */
 118                 count = lttng_list_sessions(&sessions);
 119                 if (count < 0) {
 120                         ERR("Unable to list sessions. Session name %s not found.",
 121                                         session_name);
 122                         MSG("Is there a session daemon running?");
 123                         ret = CMD_ERROR;
 124                         goto free_error;
 125                 }
 126
 127                 /* Find our session listed by the session daemon */
 128                 for (i = 0; i < count; i++) {
 129                         if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 130                                 found = 1;
 131                                 break;
 132                         }
 133                 }
 134
 135                 if (!found) {
 136                         MSG("Session name %s not found", session_name);
 137                         ret = CMD_ERROR;
 138                         goto free_sessions;
 139                 }
 140
 141                 session_live_mode = sessions[i].live_timer_interval;
 142
 143                 DBG("Session live mode set to %d", session_live_mode);
 144
 145                 if (sessions[i].enabled && !session_live_mode) {
 146                         WARN("Session %s is running. Please stop it before reading it.",
 147                                         session_name);
 148                         ret = CMD_ERROR;
 149                         goto free_sessions;
 150                 }
 151
 152                 /* If the timer interval is set we are in live mode. */
 153                 if (session_live_mode) {
 154                         trace_path = build_live_path(session_name);
 155                         if (!trace_path) {
 156                                 ret = CMD_ERROR;
 157                                 goto free_sessions;
 158                         }
 159                         free_trace_path = true;
 160                 } else {
 161                         /* Get file system session path. */
 162                         trace_path = sessions[i].path;
 163                 }
 164         } else {
 165                 trace_path = opt_trace_path;
 166         }
 167
 168         MSG("Trace directory: %s\n", trace_path);
 169
 170         ret = spawn_viewer(trace_path, opt_viewer, session_live_mode);
 171         if (ret < 0) {
 172                 /* Don't set ret so lttng can interpret the sessiond error. */
 173                 goto free_sessions;
 174         }
 175
 176 free_sessions:
 177         if (session_live_mode && free_trace_path) {
 178                 free(trace_path);
 179         }
 180         free(sessions);
 181 free_error:
 182         if (opt_session_name == NULL) {
 183                 free(session_name);
 184         }
 185 error:
 186         return ret;
 187 }
 188
 189 /*
 190  * The 'view <options>' first level command
 191  */
 192 int cmd_view(int argc, const char **argv)
 193 {
 194         int opt, ret = CMD_SUCCESS;
 195         static poptContext pc;
 196         const char *leftover = NULL;
 197
 198         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 199         poptReadDefaultConfig(pc, 0);
 200
 201         if (lttng_opt_mi) {
 202                 WARN("mi does not apply to view command");
 203         }
 204
 205         while ((opt = poptGetNextOpt(pc)) != -1) {
 206                 switch (opt) {
 207                 case OPT_HELP:
 208                         SHOW_HELP();
 209                         goto end;
 210                 case OPT_LIST_OPTIONS:
 211                         list_cmd_options(stdout, long_options);
 212                         goto end;
 213                 default:
 214                         ret = CMD_UNDEFINED;
 215                         goto end;
 216                 }
 217         }
 218
 219         opt_session_name = (char*) poptGetArg(pc);
 220
 221         leftover = poptGetArg(pc);
 222         if (leftover) {
 223                 ERR("Unknown argument: %s", leftover);
 224                 ret = CMD_ERROR;
 225                 goto end;
 226         }
 227
 228         ret = view_trace();
 229
 230 end:
 231         poptFreeContext(pc);
 232         return ret;
 233 }