src/bin/lttng/commands/enable_channels.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <popt.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #include <unistd.h>
  26 #include <inttypes.h>
  27
  28 #include "../command.h"
  29
  30 #include <src/common/sessiond-comm/sessiond-comm.h>
  31
  32 static char *opt_channels;
  33 static int opt_kernel;
  34 static char *opt_session_name;
  35 static int opt_userspace;
  36 static struct lttng_channel chan;
  37 static char *opt_output;
  38 static int opt_buffer_uid;
  39 static int opt_buffer_pid;
  40 static int opt_buffer_global;
  41
  42 enum {
  43         OPT_HELP = 1,
  44         OPT_DISCARD,
  45         OPT_OVERWRITE,
  46         OPT_SUBBUF_SIZE,
  47         OPT_NUM_SUBBUF,
  48         OPT_SWITCH_TIMER,
  49         OPT_READ_TIMER,
  50         OPT_USERSPACE,
  51         OPT_LIST_OPTIONS,
  52 };
  53
  54 static struct lttng_handle *handle;
  55
  56 const char *output_mmap = "mmap";
  57 const char *output_splice = "splice";
  58
  59 static struct poptOption long_options[] = {
  60         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  61         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  62         {"session",        's', POPT_ARG_STRING, &opt_session_name, 0, 0, 0},
  63         {"kernel",         'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0},
  64         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  65         {"discard",        0,   POPT_ARG_NONE, 0, OPT_DISCARD, 0, 0},
  66         {"overwrite",      0,   POPT_ARG_NONE, 0, OPT_OVERWRITE, 0, 0},
  67         {"subbuf-size",    0,   POPT_ARG_DOUBLE, 0, OPT_SUBBUF_SIZE, 0, 0},
  68         {"num-subbuf",     0,   POPT_ARG_INT, 0, OPT_NUM_SUBBUF, 0, 0},
  69         {"switch-timer",   0,   POPT_ARG_INT, 0, OPT_SWITCH_TIMER, 0, 0},
  70         {"read-timer",     0,   POPT_ARG_INT, 0, OPT_READ_TIMER, 0, 0},
  71         {"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  72         {"output",         0,   POPT_ARG_STRING, &opt_output, 0, 0, 0},
  73         {"buffers-uid",    0,   POPT_ARG_VAL, &opt_buffer_uid, 1, 0, 0},
  74         {"buffers-pid",    0,   POPT_ARG_VAL, &opt_buffer_pid, 1, 0, 0},
  75         {"buffers-global", 0,   POPT_ARG_VAL, &opt_buffer_global, 1, 0, 0},
  76         {0, 0, 0, 0, 0, 0, 0}
  77 };
  78
  79 /*
  80  * usage
  81  */
  82 static void usage(FILE *ofp)
  83 {
  84         fprintf(ofp, "usage: lttng enable-channel NAME[,NAME2,...] [-u|-k] [OPTIONS]\n");
  85         fprintf(ofp, "\n");
  86         fprintf(ofp, "Options:\n");
  87         fprintf(ofp, "  -h, --help               Show this help\n");
  88         fprintf(ofp, "      --list-options       Simple listing of options\n");
  89         fprintf(ofp, "  -s, --session NAME       Apply to session name\n");
  90         fprintf(ofp, "  -k, --kernel             Apply to the kernel tracer\n");
  91         fprintf(ofp, "  -u, --userspace          Apply to the user-space tracer\n");
  92         fprintf(ofp, "\n");
  93         fprintf(ofp, "Channel options:\n");
  94         fprintf(ofp, "      --discard            Discard event when buffers are full%s\n",
  95                 DEFAULT_CHANNEL_OVERWRITE ? "" : " (default)");
  96         fprintf(ofp, "      --overwrite          Flight recorder mode%s\n",
  97                 DEFAULT_CHANNEL_OVERWRITE ? " (default)" : "");
  98         fprintf(ofp, "      --subbuf-size SIZE   Subbuffer size in bytes\n");
  99         fprintf(ofp, "                               (default: %zu, kernel default: %zu)\n",
 100                 default_get_channel_subbuf_size(),
 101                 default_get_kernel_channel_subbuf_size());
 102         fprintf(ofp, "                               Needs to be a power of 2 for\n");
 103         fprintf(ofp, "                               kernel and ust tracers\n");
 104         fprintf(ofp, "      --num-subbuf NUM     Number of subbufers\n");
 105         fprintf(ofp, "                               (default: %u)\n",
 106                 DEFAULT_CHANNEL_SUBBUF_NUM);
 107         fprintf(ofp, "                               Needs to be a power of 2 for\n");
 108         fprintf(ofp, "                               kernel and ust tracers\n");
 109         fprintf(ofp, "      --switch-timer USEC  Switch timer interval in usec (default: %u)\n",
 110                 DEFAULT_CHANNEL_SWITCH_TIMER);
 111         fprintf(ofp, "      --read-timer USEC    Read timer interval in usec (default: %u)\n",
 112                 DEFAULT_CHANNEL_READ_TIMER);
 113         fprintf(ofp, "      --output TYPE        Channel output type (Values: %s, %s)\n",
 114                         output_mmap, output_splice);
 115         fprintf(ofp, "      --buffers-uid        Use per UID buffer (-u only)\n");
 116         fprintf(ofp, "      --buffers-pid        Use per PID buffer (-u only)\n");
 117         fprintf(ofp, "      --buffers-global     Use shared buffer for the whole system (-k only)\n");
 118         fprintf(ofp, "\n");
 119 }
 120
 121 /*
 122  * Set default attributes depending on those already defined from the command
 123  * line.
 124  */
 125 static void set_default_attr(struct lttng_domain *dom)
 126 {
 127         struct lttng_channel_attr default_attr;
 128
 129         /* Set attributes */
 130         lttng_channel_set_default_attr(dom, &default_attr);
 131
 132         if (chan.attr.overwrite == -1) {
 133                 chan.attr.overwrite = default_attr.overwrite;
 134         }
 135         if (chan.attr.subbuf_size == -1) {
 136                 chan.attr.subbuf_size = default_attr.subbuf_size;
 137         }
 138         if (chan.attr.num_subbuf == -1) {
 139                 chan.attr.num_subbuf = default_attr.num_subbuf;
 140         }
 141         if (chan.attr.switch_timer_interval == -1) {
 142                 chan.attr.switch_timer_interval = default_attr.switch_timer_interval;
 143         }
 144         if (chan.attr.read_timer_interval == -1) {
 145                 chan.attr.read_timer_interval = default_attr.read_timer_interval;
 146         }
 147         if (chan.attr.output == -1) {
 148                 chan.attr.output = default_attr.output;
 149         }
 150 }
 151
 152 /*
 153  * Adding channel using the lttng API.
 154  */
 155 static int enable_channel(char *session_name)
 156 {
 157         int ret = CMD_SUCCESS, warn = 0;
 158         char *channel_name;
 159         struct lttng_domain dom;
 160
 161         memset(&dom, 0, sizeof(dom));
 162
 163         /* Create lttng domain */
 164         if (opt_kernel) {
 165                 dom.type = LTTNG_DOMAIN_KERNEL;
 166                 dom.buf_type = LTTNG_BUFFER_GLOBAL;
 167         } else if (opt_userspace) {
 168                 dom.type = LTTNG_DOMAIN_UST;
 169                 if (opt_buffer_uid) {
 170                         dom.buf_type = LTTNG_BUFFER_PER_UID;
 171                 } else {
 172                         dom.buf_type = LTTNG_BUFFER_PER_PID;
 173                 }
 174         } else {
 175                 ERR("Please specify a tracer (-k/--kernel or -u/--userspace)");
 176                 ret = CMD_ERROR;
 177                 goto error;
 178         }
 179
 180         set_default_attr(&dom);
 181
 182         /* Setting channel output */
 183         if (opt_output) {
 184                 if (!strncmp(output_mmap, opt_output, strlen(output_mmap))) {
 185                         chan.attr.output = LTTNG_EVENT_MMAP;
 186                 } else if (!strncmp(output_splice, opt_output, strlen(output_splice))) {
 187                         chan.attr.output = LTTNG_EVENT_SPLICE;
 188                 } else {
 189                         ERR("Unknown output type %s. Possible values are: %s, %s\n",
 190                                         opt_output, output_mmap, output_splice);
 191                         usage(stderr);
 192                         ret = CMD_ERROR;
 193                         goto error;
 194                 }
 195         }
 196
 197         handle = lttng_create_handle(session_name, &dom);
 198         if (handle == NULL) {
 199                 ret = -1;
 200                 goto error;
 201         }
 202
 203         /* Strip channel list (format: chan1,chan2,...) */
 204         channel_name = strtok(opt_channels, ",");
 205         while (channel_name != NULL) {
 206                 /* Copy channel name and normalize it */
 207                 strncpy(chan.name, channel_name, NAME_MAX);
 208                 chan.name[NAME_MAX - 1] = '\0';
 209
 210                 DBG("Enabling channel %s", channel_name);
 211
 212                 ret = lttng_enable_channel(handle, &chan);
 213                 if (ret < 0) {
 214                         switch (-ret) {
 215                         case LTTNG_ERR_KERN_CHAN_EXIST:
 216                         case LTTNG_ERR_UST_CHAN_EXIST:
 217                                 WARN("Channel %s: %s (session %s", channel_name,
 218                                                 lttng_strerror(ret), session_name);
 219                                 goto error;
 220                         default:
 221                                 ERR("Channel %s: %s (session %s)", channel_name,
 222                                                 lttng_strerror(ret), session_name);
 223                                 break;
 224                         }
 225                         warn = 1;
 226                 } else {
 227                         MSG("%s channel %s enabled for session %s",
 228                                         opt_kernel ? "Kernel" : "UST", channel_name,
 229                                         session_name);
 230                 }
 231
 232                 /* Next event */
 233                 channel_name = strtok(NULL, ",");
 234         }
 235
 236         ret = CMD_SUCCESS;
 237
 238 error:
 239         if (warn) {
 240                 ret = CMD_WARNING;
 241         }
 242
 243         lttng_destroy_handle(handle);
 244
 245         return ret;
 246 }
 247
 248 /*
 249  * Default value for channel configuration.
 250  */
 251 static void init_channel_config(void)
 252 {
 253         /*
 254          * Put -1 everywhere so we can identify those set by the command line and
 255          * those needed to be set by the default values.
 256          */
 257         memset(&chan.attr, -1, sizeof(chan.attr));
 258 }
 259
 260 /*
 261  * Add channel to trace session
 262  */
 263 int cmd_enable_channels(int argc, const char **argv)
 264 {
 265         int opt, ret = CMD_SUCCESS;
 266         static poptContext pc;
 267         char *session_name = NULL;
 268
 269         init_channel_config();
 270
 271         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 272         poptReadDefaultConfig(pc, 0);
 273
 274         while ((opt = poptGetNextOpt(pc)) != -1) {
 275                 switch (opt) {
 276                 case OPT_HELP:
 277                         usage(stdout);
 278                         goto end;
 279                 case OPT_DISCARD:
 280                         chan.attr.overwrite = 0;
 281                         DBG("Channel set to discard");
 282                         break;
 283                 case OPT_OVERWRITE:
 284                         chan.attr.overwrite = 1;
 285                         DBG("Channel set to overwrite");
 286                         break;
 287                 case OPT_SUBBUF_SIZE:
 288                         /* TODO Replace atol with strtol and check for errors */
 289                         chan.attr.subbuf_size = atol(poptGetOptArg(pc));
 290                         DBG("Channel subbuf size set to %" PRIu64, chan.attr.subbuf_size);
 291                         break;
 292                 case OPT_NUM_SUBBUF:
 293                         /* TODO Replace atoi with strtol and check for errors */
 294                         chan.attr.num_subbuf = atoi(poptGetOptArg(pc));
 295                         DBG("Channel subbuf num set to %" PRIu64, chan.attr.num_subbuf);
 296                         break;
 297                 case OPT_SWITCH_TIMER:
 298                         /* TODO Replace atoi with strtol and check for errors */
 299                         chan.attr.switch_timer_interval = atoi(poptGetOptArg(pc));
 300                         DBG("Channel switch timer interval set to %d", chan.attr.switch_timer_interval);
 301                         break;
 302                 case OPT_READ_TIMER:
 303                         /* TODO Replace atoi with strtol and check for errors */
 304                         chan.attr.read_timer_interval = atoi(poptGetOptArg(pc));
 305                         DBG("Channel read timer interval set to %d", chan.attr.read_timer_interval);
 306                         break;
 307                 case OPT_USERSPACE:
 308                         opt_userspace = 1;
 309                         break;
 310                 case OPT_LIST_OPTIONS:
 311                         list_cmd_options(stdout, long_options);
 312                         goto end;
 313                 default:
 314                         usage(stderr);
 315                         ret = CMD_UNDEFINED;
 316                         goto end;
 317                 }
 318         }
 319
 320         opt_channels = (char*) poptGetArg(pc);
 321         if (opt_channels == NULL) {
 322                 ERR("Missing channel name.\n");
 323                 usage(stderr);
 324                 ret = CMD_ERROR;
 325                 goto end;
 326         }
 327
 328         if (!opt_session_name) {
 329                 session_name = get_session_name();
 330                 if (session_name == NULL) {
 331                         ret = CMD_ERROR;
 332                         goto end;
 333                 }
 334         } else {
 335                 session_name = opt_session_name;
 336         }
 337
 338         ret = enable_channel(session_name);
 339
 340 end:
 341         if (!opt_session_name && session_name) {
 342                 free(session_name);
 343         }
 344         poptFreeContext(pc);
 345         return ret;
 346 }