src/bin/lttng/commands/set_session.cpp

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   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/mi-lttng.hpp>
  18
  19 #include "../command.hpp"
  20
  21 #ifdef LTTNG_EMBED_HELP
  22 static const char help_msg[] =
  23 #include <lttng-set-session.1.h>
  24 ;
  25 #endif
  26
  27 enum {
  28         OPT_HELP = 1,
  29         OPT_LIST_OPTIONS,
  30 };
  31
  32 static struct mi_writer *writer;
  33
  34 static struct poptOption long_options[] = {
  35         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  36         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  37         {"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  38         {0, 0, 0, 0, 0, 0, 0}
  39 };
  40
  41 /*
  42  * Print the necessary mi for a session and name.
  43  */
  44 static int mi_print(const char *session_name)
  45 {
  46         int ret;
  47
  48         LTTNG_ASSERT(writer);
  49         LTTNG_ASSERT(session_name);
  50
  51         /*
  52          * Open a sessions element
  53          * This is purely for validation purpose
  54          */
  55         ret = mi_lttng_sessions_open(writer);
  56         if (ret) {
  57                 goto end;
  58         }
  59
  60         /* Open a session element */
  61         ret = mi_lttng_writer_open_element(writer, config_element_session);
  62         if (ret) {
  63                 goto end;
  64         }
  65
  66         /* Session name */
  67         ret = mi_lttng_writer_write_element_string(writer , config_element_name,
  68                         session_name);
  69         if (ret) {
  70                 goto end;
  71         }
  72
  73         /* Close session and sessions element */
  74         ret = mi_lttng_close_multi_element(writer, 2);
  75         if (ret) {
  76                 goto end;
  77         }
  78 end:
  79         return ret;
  80 }
  81
  82 /*
  83  *  set_session
  84  */
  85 static int set_session(const char *session_name)
  86 {
  87         int ret = CMD_SUCCESS;
  88         int count, i;
  89         unsigned int session_found = 0;
  90         struct lttng_session *sessions;
  91
  92         if (session_name && strlen(session_name) > NAME_MAX) {
  93                 ERR("Session name too long. Length must be lower or equal to %d",
  94                         NAME_MAX);
  95                 ret = CMD_ERROR;
  96                 goto end;
  97         }
  98
  99         count = lttng_list_sessions(&sessions);
 100         if (count < 0) {
 101                 ret = CMD_ERROR;
 102                 ERR("%s", lttng_strerror(count));
 103                 goto end;
 104         }
 105
 106         for (i = 0; i < count; i++) {
 107                 if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 108                         session_found = 1;
 109                         break;
 110                 }
 111         }
 112
 113         if (!session_found) {
 114                 ERR("Session '%s' not found", session_name);
 115                 ret = CMD_ERROR;
 116                 goto error;
 117         }
 118
 119         ret = config_init(session_name);
 120         if (ret < 0) {
 121                 ERR("Unable to set session name");
 122                 ret = CMD_ERROR;
 123                 goto error;
 124         }
 125
 126         MSG("Session set to %s", session_name);
 127         if (lttng_opt_mi) {
 128                 ret = mi_print(session_name);
 129                 if (ret) {
 130                         ret = CMD_ERROR;
 131                         goto error;
 132                 }
 133         }
 134
 135         ret = CMD_SUCCESS;
 136
 137 error:
 138         free(sessions);
 139 end:
 140         return ret;
 141 }
 142
 143 /*
 144  *  cmd_set_session
 145  */
 146 int cmd_set_session(int argc, const char **argv)
 147 {
 148         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 149         static poptContext pc;
 150         const char *arg_session_name = NULL;
 151
 152         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 153         poptReadDefaultConfig(pc, 0);
 154
 155         while ((opt = poptGetNextOpt(pc)) != -1) {
 156                 switch (opt) {
 157                 case OPT_HELP:
 158                         SHOW_HELP();
 159                         goto end;
 160                 case OPT_LIST_OPTIONS:
 161                         list_cmd_options(stdout, long_options);
 162                         goto end;
 163                 default:
 164                         ret = CMD_UNDEFINED;
 165                         goto end;
 166                 }
 167         }
 168
 169         arg_session_name = poptGetArg(pc);
 170         if (arg_session_name == NULL) {
 171                 ERR("Missing session name");
 172                 ret = CMD_ERROR;
 173                 goto end;
 174         }
 175
 176         /* Mi check */
 177         if (lttng_opt_mi) {
 178                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 179                 if (!writer) {
 180                         ret = -LTTNG_ERR_NOMEM;
 181                         goto end;
 182                 }
 183
 184                 /* Open command element */
 185                 ret = mi_lttng_writer_command_open(writer,
 186                                 mi_lttng_element_command_set_session);
 187                 if (ret) {
 188                         ret = CMD_ERROR;
 189                         goto end;
 190                 }
 191
 192                 /* Open output element */
 193                 ret = mi_lttng_writer_open_element(writer,
 194                                 mi_lttng_element_command_output);
 195                 if (ret) {
 196                         ret = CMD_ERROR;
 197                         goto end;
 198                 }
 199         }
 200
 201         command_ret = set_session(arg_session_name);
 202         if (command_ret) {
 203                 success = 0;
 204         }
 205
 206         /* Mi closing */
 207         if (lttng_opt_mi) {
 208                 /* Close  output element */
 209                 ret = mi_lttng_writer_close_element(writer);
 210                 if (ret) {
 211                         ret = CMD_ERROR;
 212                         goto end;
 213                 }
 214
 215                 /* Success ? */
 216                 ret = mi_lttng_writer_write_element_bool(writer,
 217                                 mi_lttng_element_command_success, success);
 218                 if (ret) {
 219                         ret = CMD_ERROR;
 220                         goto end;
 221                 }
 222
 223                 /* Command element close */
 224                 ret = mi_lttng_writer_command_close(writer);
 225                 if (ret) {
 226                         ret = CMD_ERROR;
 227                         goto end;
 228                 }
 229         }
 230
 231 end:
 232         /* Mi clean-up */
 233         if (writer && mi_lttng_writer_destroy(writer)) {
 234                 /* Preserve original error code */
 235                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 236         }
 237
 238         /* Overwrite ret if an error occurred during set_session() */
 239         ret = command_ret ? command_ret : ret;
 240
 241         poptFreeContext(pc);
 242         return ret;
 243 }