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