src/bin/lttng/commands/set_session.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   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 #include <assert.h>
  17
  18 #include <common/mi-lttng.h>
  19
  20 #include "../command.h"
  21
  22 static char *opt_session_name;
  23
  24 #ifdef LTTNG_EMBED_HELP
  25 static const char help_msg[] =
  26 #include <lttng-set-session.1.h>
  27 ;
  28 #endif
  29
  30 enum {
  31         OPT_HELP = 1,
  32         OPT_LIST_OPTIONS,
  33 };
  34
  35 static struct mi_writer *writer;
  36
  37 static struct poptOption long_options[] = {
  38         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  39         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  40         {"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  41         {0, 0, 0, 0, 0, 0, 0}
  42 };
  43
  44 /*
  45  * Print the necessary mi for a session and name.
  46  */
  47 static int mi_print(char *session_name)
  48 {
  49         int ret;
  50
  51         assert(writer);
  52         assert(session_name);
  53
  54         /*
  55          * Open a sessions element
  56          * This is purely for validation purpose
  57          */
  58         ret = mi_lttng_sessions_open(writer);
  59         if (ret) {
  60                 goto end;
  61         }
  62
  63         /* Open a session element */
  64         ret = mi_lttng_writer_open_element(writer, config_element_session);
  65         if (ret) {
  66                 goto end;
  67         }
  68
  69         /* Session name */
  70         ret = mi_lttng_writer_write_element_string(writer , config_element_name,
  71                         session_name);
  72         if (ret) {
  73                 goto end;
  74         }
  75
  76         /* Close session and sessions element */
  77         ret = mi_lttng_close_multi_element(writer, 2);
  78         if (ret) {
  79                 goto end;
  80         }
  81 end:
  82         return ret;
  83 }
  84
  85 /*
  86  *  set_session
  87  */
  88 static int set_session(void)
  89 {
  90         int ret = CMD_SUCCESS;
  91         int count, i;
  92         unsigned int session_found = 0;
  93         struct lttng_session *sessions;
  94
  95         if (opt_session_name && strlen(opt_session_name) > NAME_MAX) {
  96                 ERR("Session name too long. Length must be lower or equal to %d",
  97                         NAME_MAX);
  98                 ret = CMD_ERROR;
  99                 goto end;
 100         }
 101
 102         count = lttng_list_sessions(&sessions);
 103         if (count < 0) {
 104                 ret = CMD_ERROR;
 105                 ERR("%s", lttng_strerror(count));
 106                 goto end;
 107         }
 108
 109         for (i = 0; i < count; i++) {
 110                 if (strncmp(sessions[i].name, opt_session_name, NAME_MAX) == 0) {
 111                         session_found = 1;
 112                         break;
 113                 }
 114         }
 115
 116         if (!session_found) {
 117                 ERR("Session '%s' not found", opt_session_name);
 118                 ret = CMD_ERROR;
 119                 goto error;
 120         }
 121
 122         ret = config_init(opt_session_name);
 123         if (ret < 0) {
 124                 ERR("Unable to set session name");
 125                 ret = CMD_ERROR;
 126                 goto error;
 127         }
 128
 129         MSG("Session set to %s", opt_session_name);
 130         if (lttng_opt_mi) {
 131                 ret = mi_print(opt_session_name);
 132                 if (ret) {
 133                         ret = CMD_ERROR;
 134                         goto error;
 135                 }
 136         }
 137
 138         ret = CMD_SUCCESS;
 139
 140 error:
 141         free(sessions);
 142 end:
 143         return ret;
 144 }
 145
 146 /*
 147  *  cmd_set_session
 148  */
 149 int cmd_set_session(int argc, const char **argv)
 150 {
 151         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 152         static poptContext pc;
 153
 154         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 155         poptReadDefaultConfig(pc, 0);
 156
 157         while ((opt = poptGetNextOpt(pc)) != -1) {
 158                 switch (opt) {
 159                 case OPT_HELP:
 160                         SHOW_HELP();
 161                         goto end;
 162                 case OPT_LIST_OPTIONS:
 163                         list_cmd_options(stdout, long_options);
 164                         goto end;
 165                 default:
 166                         ret = CMD_UNDEFINED;
 167                         goto end;
 168                 }
 169         }
 170
 171         opt_session_name = (char *) poptGetArg(pc);
 172         if (opt_session_name == NULL) {
 173                 ERR("Missing session name");
 174                 ret = CMD_ERROR;
 175                 goto end;
 176         }
 177
 178         /* Mi check */
 179         if (lttng_opt_mi) {
 180                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 181                 if (!writer) {
 182                         ret = -LTTNG_ERR_NOMEM;
 183                         goto end;
 184                 }
 185
 186                 /* Open command element */
 187                 ret = mi_lttng_writer_command_open(writer,
 188                                 mi_lttng_element_command_set_session);
 189                 if (ret) {
 190                         ret = CMD_ERROR;
 191                         goto end;
 192                 }
 193
 194                 /* Open output element */
 195                 ret = mi_lttng_writer_open_element(writer,
 196                                 mi_lttng_element_command_output);
 197                 if (ret) {
 198                         ret = CMD_ERROR;
 199                         goto end;
 200                 }
 201         }
 202
 203         command_ret = set_session();
 204         if (command_ret) {
 205                 success = 0;
 206         }
 207
 208         /* Mi closing */
 209         if (lttng_opt_mi) {
 210                 /* Close  output element */
 211                 ret = mi_lttng_writer_close_element(writer);
 212                 if (ret) {
 213                         ret = CMD_ERROR;
 214                         goto end;
 215                 }
 216
 217                 /* Success ? */
 218                 ret = mi_lttng_writer_write_element_bool(writer,
 219                                 mi_lttng_element_command_success, success);
 220                 if (ret) {
 221                         ret = CMD_ERROR;
 222                         goto end;
 223                 }
 224
 225                 /* Command element close */
 226                 ret = mi_lttng_writer_command_close(writer);
 227                 if (ret) {
 228                         ret = CMD_ERROR;
 229                         goto end;
 230                 }
 231         }
 232
 233 end:
 234         /* Mi clean-up */
 235         if (writer && mi_lttng_writer_destroy(writer)) {
 236                 /* Preserve original error code */
 237                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 238         }
 239
 240         /* Overwrite ret if an error occurred during set_session() */
 241         ret = command_ret ? command_ret : ret;
 242
 243         poptFreeContext(pc);
 244         return ret;
 245 }