src/bin/lttng/commands/set_session.c

   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 #include <assert.h>
  17
  18 #include <common/mi-lttng.h>
  19
  20 #include "../command.h"
  21
  22 #ifdef LTTNG_EMBED_HELP
  23 static const char help_msg[] =
  24 #include <lttng-set-session.1.h>
  25 ;
  26 #endif
  27
  28 enum {
  29         OPT_HELP = 1,
  30         OPT_LIST_OPTIONS,
  31 };
  32
  33 static struct mi_writer *writer;
  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         {0, 0, 0, 0, 0, 0, 0}
  40 };
  41
  42 /*
  43  * Print the necessary mi for a session and name.
  44  */
  45 static int mi_print(const char *session_name)
  46 {
  47         int ret;
  48
  49         assert(writer);
  50         assert(session_name);
  51
  52         /*
  53          * Open a sessions element
  54          * This is purely for validation purpose
  55          */
  56         ret = mi_lttng_sessions_open(writer);
  57         if (ret) {
  58                 goto end;
  59         }
  60
  61         /* Open a session element */
  62         ret = mi_lttng_writer_open_element(writer, config_element_session);
  63         if (ret) {
  64                 goto end;
  65         }
  66
  67         /* Session name */
  68         ret = mi_lttng_writer_write_element_string(writer , config_element_name,
  69                         session_name);
  70         if (ret) {
  71                 goto end;
  72         }
  73
  74         /* Close session and sessions element */
  75         ret = mi_lttng_close_multi_element(writer, 2);
  76         if (ret) {
  77                 goto end;
  78         }
  79 end:
  80         return ret;
  81 }
  82
  83 /*
  84  *  set_session
  85  */
  86 static int set_session(const char *session_name)
  87 {
  88         int ret = CMD_SUCCESS;
  89         int count, i;
  90         unsigned int session_found = 0;
  91         struct lttng_session *sessions;
  92
  93         if (session_name && strlen(session_name) > NAME_MAX) {
  94                 ERR("Session name too long. Length must be lower or equal to %d",
  95                         NAME_MAX);
  96                 ret = CMD_ERROR;
  97                 goto end;
  98         }
  99
 100         count = lttng_list_sessions(&sessions);
 101         if (count < 0) {
 102                 ret = CMD_ERROR;
 103                 ERR("%s", lttng_strerror(count));
 104                 goto end;
 105         }
 106
 107         for (i = 0; i < count; i++) {
 108                 if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 109                         session_found = 1;
 110                         break;
 111                 }
 112         }
 113
 114         if (!session_found) {
 115                 ERR("Session '%s' not found", session_name);
 116                 ret = CMD_ERROR;
 117                 goto error;
 118         }
 119
 120         ret = config_init(session_name);
 121         if (ret < 0) {
 122                 ERR("Unable to set session name");
 123                 ret = CMD_ERROR;
 124                 goto error;
 125         }
 126
 127         MSG("Session set to %s", session_name);
 128         if (lttng_opt_mi) {
 129                 ret = mi_print(session_name);
 130                 if (ret) {
 131                         ret = CMD_ERROR;
 132                         goto error;
 133                 }
 134         }
 135
 136         ret = CMD_SUCCESS;
 137
 138 error:
 139         free(sessions);
 140 end:
 141         return ret;
 142 }
 143
 144 /*
 145  *  cmd_set_session
 146  */
 147 int cmd_set_session(int argc, const char **argv)
 148 {
 149         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 150         static poptContext pc;
 151         const char *arg_session_name = NULL;
 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         arg_session_name = poptGetArg(pc);
 171         if (arg_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(arg_session_name);
 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 }