libtracectl/marker-control.c

   1 /*
   2  * Copyright (C) 2007 Mathieu Desnoyers
   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 as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * LTT marker control module over /proc
  19  */
  20
  21 //ust// #include <linux/proc_fs.h>
  22 //ust// #include <linux/module.h>
  23 //ust// #include <linux/stat.h>
  24 //ust// #include <linux/vmalloc.h>
  25 //ust// #include <linux/marker.h>
  26 //ust// #include <linux/ltt-tracer.h>
  27 //ust// #include <linux/uaccess.h>
  28 //ust// #include <linux/string.h>
  29 //ust// #include <linux/ctype.h>
  30 //ust// #include <linux/list.h>
  31 //ust// #include <linux/mutex.h>
  32 //ust// #include <linux/seq_file.h>
  33 //ust// #include <linux/slab.h>
  34 #include "kernelcompat.h"
  35 #include "list.h"
  36 #include "tracer.h"
  37 #include "usterr.h"
  38
  39 #define DEFAULT_CHANNEL "cpu"
  40 #define DEFAULT_PROBE "default"
  41
  42 LIST_HEAD(probes_list);
  43
  44 /*
  45  * Mutex protecting the probe slab cache.
  46  * Nests inside the traces mutex.
  47  */
  48 DEFINE_MUTEX(probes_mutex);
  49
  50 struct ltt_available_probe default_probe = {
  51         .name = "default",
  52         .format = NULL,
  53         .probe_func = ltt_vtrace,
  54         .callbacks[0] = ltt_serialize_data,
  55 };
  56
  57 //ust//static struct kmem_cache *markers_loaded_cachep;
  58 static LIST_HEAD(markers_loaded_list);
  59 /*
  60  * List sorted by name strcmp order.
  61  */
  62 static LIST_HEAD(probes_registered_list);
  63
  64 //ust// static struct proc_dir_entry *pentry;
  65
  66 //ust// static struct file_operations ltt_fops;
  67
  68 static struct ltt_available_probe *get_probe_from_name(const char *pname)
  69 {
  70         struct ltt_available_probe *iter;
  71         int comparison, found = 0;
  72
  73         if (!pname)
  74                 pname = DEFAULT_PROBE;
  75         list_for_each_entry(iter, &probes_registered_list, node) {
  76                 comparison = strcmp(pname, iter->name);
  77                 if (!comparison)
  78                         found = 1;
  79                 if (comparison <= 0)
  80                         break;
  81         }
  82         if (found)
  83                 return iter;
  84         else
  85                 return NULL;
  86 }
  87
  88 static char *skip_spaces(char *buf)
  89 {
  90         while (*buf != '\0' && isspace(*buf))
  91                 buf++;
  92         return buf;
  93 }
  94
  95 static char *skip_nonspaces(char *buf)
  96 {
  97         while (*buf != '\0' && !isspace(*buf))
  98                 buf++;
  99         return buf;
 100 }
 101
 102 static void get_marker_string(char *buf, char **start,
 103                 char **end)
 104 {
 105         *start = skip_spaces(buf);
 106         *end = skip_nonspaces(*start);
 107         **end = '\0';
 108 }
 109
 110 int ltt_probe_register(struct ltt_available_probe *pdata)
 111 {
 112         int ret = 0;
 113         int comparison;
 114         struct ltt_available_probe *iter;
 115
 116         mutex_lock(&probes_mutex);
 117         list_for_each_entry_reverse(iter, &probes_registered_list, node) {
 118                 comparison = strcmp(pdata->name, iter->name);
 119                 if (!comparison) {
 120                         ret = -EBUSY;
 121                         goto end;
 122                 } else if (comparison > 0) {
 123                         /* We belong to the location right after iter. */
 124                         list_add(&pdata->node, &iter->node);
 125                         goto end;
 126                 }
 127         }
 128         /* Should be added at the head of the list */
 129         list_add(&pdata->node, &probes_registered_list);
 130 end:
 131         mutex_unlock(&probes_mutex);
 132         return ret;
 133 }
 134 EXPORT_SYMBOL_GPL(ltt_probe_register);
 135
 136 /*
 137  * Called when a probe does not want to be called anymore.
 138  */
 139 int ltt_probe_unregister(struct ltt_available_probe *pdata)
 140 {
 141         int ret = 0;
 142         struct ltt_active_marker *amark, *tmp;
 143
 144         mutex_lock(&probes_mutex);
 145         list_for_each_entry_safe(amark, tmp, &markers_loaded_list, node) {
 146                 if (amark->probe == pdata) {
 147                         ret = marker_probe_unregister_private_data(
 148                                 pdata->probe_func, amark);
 149                         if (ret)
 150                                 goto end;
 151                         list_del(&amark->node);
 152                         free(amark);
 153                 }
 154         }
 155         list_del(&pdata->node);
 156 end:
 157         mutex_unlock(&probes_mutex);
 158         return ret;
 159 }
 160 EXPORT_SYMBOL_GPL(ltt_probe_unregister);
 161
 162 /*
 163  * Connect marker "mname" to probe "pname".
 164  * Only allow _only_ probe instance to be connected to a marker.
 165  */
 166 int ltt_marker_connect(const char *channel, const char *mname,
 167                        const char *pname)
 168
 169 {
 170         int ret;
 171         struct ltt_active_marker *pdata;
 172         struct ltt_available_probe *probe;
 173
 174         ltt_lock_traces();
 175         mutex_lock(&probes_mutex);
 176         probe = get_probe_from_name(pname);
 177         if (!probe) {
 178                 ret = -ENOENT;
 179                 goto end;
 180         }
 181         pdata = marker_get_private_data(channel, mname, probe->probe_func, 0);
 182         if (pdata && !IS_ERR(pdata)) {
 183                 ret = -EEXIST;
 184                 goto end;
 185         }
 186         pdata = zmalloc(sizeof(struct ltt_active_marker));
 187         if (!pdata) {
 188                 ret = -ENOMEM;
 189                 goto end;
 190         }
 191         pdata->probe = probe;
 192         /*
 193          * ID has priority over channel in case of conflict.
 194          */
 195         ret = marker_probe_register(channel, mname, NULL,
 196                 probe->probe_func, pdata);
 197         if (ret)
 198                 free(pdata);
 199         else
 200                 list_add(&pdata->node, &markers_loaded_list);
 201 end:
 202         mutex_unlock(&probes_mutex);
 203         ltt_unlock_traces();
 204         return ret;
 205 }
 206 EXPORT_SYMBOL_GPL(ltt_marker_connect);
 207
 208 /*
 209  * Disconnect marker "mname", probe "pname".
 210  */
 211 int ltt_marker_disconnect(const char *channel, const char *mname,
 212                           const char *pname)
 213 {
 214         struct ltt_active_marker *pdata;
 215         struct ltt_available_probe *probe;
 216         int ret = 0;
 217
 218         mutex_lock(&probes_mutex);
 219         probe = get_probe_from_name(pname);
 220         if (!probe) {
 221                 ret = -ENOENT;
 222                 goto end;
 223         }
 224         pdata = marker_get_private_data(channel, mname, probe->probe_func, 0);
 225         if (IS_ERR(pdata)) {
 226                 ret = PTR_ERR(pdata);
 227                 goto end;
 228         } else if (!pdata) {
 229                 /*
 230                  * Not registered by us.
 231                  */
 232                 ret = -EPERM;
 233                 goto end;
 234         }
 235         ret = marker_probe_unregister(channel, mname, probe->probe_func, pdata);
 236         if (ret)
 237                 goto end;
 238         else {
 239                 list_del(&pdata->node);
 240                 free(pdata);
 241         }
 242 end:
 243         mutex_unlock(&probes_mutex);
 244         return ret;
 245 }
 246 EXPORT_SYMBOL_GPL(ltt_marker_disconnect);
 247
 248 /*
 249  * function handling proc entry write.
 250  *
 251  * connect <channel name> <marker name> [<probe name>]]
 252  * disconnect <channel name> <marker name> [<probe name>]
 253  */
 254 //ust// static ssize_t ltt_write(struct file *file, const char __user *buffer,
 255 //ust//                            size_t count, loff_t *offset)
 256 //ust// {
 257 //ust//         char *kbuf;
 258 //ust//         char *iter, *marker_action, *arg[4];
 259 //ust//         ssize_t ret;
 260 //ust//         int i;
 261 //ust//
 262 //ust//         if (!count)
 263 //ust//                 return -EINVAL;
 264 //ust//
 265 //ust//         kbuf = vmalloc(count + 1);
 266 //ust//         kbuf[count] = '\0';             /* Transform into a string */
 267 //ust//         ret = copy_from_user(kbuf, buffer, count);
 268 //ust//         if (ret) {
 269 //ust//                 ret = -EINVAL;
 270 //ust//                 goto end;
 271 //ust//         }
 272 //ust//         get_marker_string(kbuf, &marker_action, &iter);
 273 //ust//         if (!marker_action || marker_action == iter) {
 274 //ust//                 ret = -EINVAL;
 275 //ust//                 goto end;
 276 //ust//         }
 277 //ust//         for (i = 0; i < 4; i++) {
 278 //ust//                 arg[i] = NULL;
 279 //ust//                 if (iter < kbuf + count) {
 280 //ust//                         iter++;                 /* skip the added '\0' */
 281 //ust//                         get_marker_string(iter, &arg[i], &iter);
 282 //ust//                         if (arg[i] == iter)
 283 //ust//                                 arg[i] = NULL;
 284 //ust//                 }
 285 //ust//         }
 286 //ust//
 287 //ust//         if (!arg[0] || !arg[1]) {
 288 //ust//                 ret = -EINVAL;
 289 //ust//                 goto end;
 290 //ust//         }
 291 //ust//
 292 //ust//         if (!strcmp(marker_action, "connect")) {
 293 //ust//                 ret = ltt_marker_connect(arg[0], arg[1], arg[2]);
 294 //ust//                 if (ret)
 295 //ust//                         goto end;
 296 //ust//         } else if (!strcmp(marker_action, "disconnect")) {
 297 //ust//                 ret = ltt_marker_disconnect(arg[0], arg[1], arg[2]);
 298 //ust//                 if (ret)
 299 //ust//                         goto end;
 300 //ust//         }
 301 //ust//         ret = count;
 302 //ust// end:
 303 //ust//         vfree(kbuf);
 304 //ust//         return ret;
 305 //ust// }
 306 //ust//
 307 //ust// static void *s_next(struct seq_file *m, void *p, loff_t *pos)
 308 //ust// {
 309 //ust//         struct marker_iter *iter = m->private;
 310 //ust//
 311 //ust//         marker_iter_next(iter);
 312 //ust//         if (!iter->marker) {
 313 //ust//                 /*
 314 //ust//                  * Setting the iter module to -1UL will make sure
 315 //ust//                  * that no module can possibly hold the current marker.
 316 //ust//                  */
 317 //ust//                 iter->module = (void *)-1UL;
 318 //ust//                 return NULL;
 319 //ust//         }
 320 //ust//         return iter->marker;
 321 //ust// }
 322 //ust//
 323 //ust// static void *s_start(struct seq_file *m, loff_t *pos)
 324 //ust// {
 325 //ust//         struct marker_iter *iter = m->private;
 326 //ust//
 327 //ust//         if (!*pos)
 328 //ust//                 marker_iter_reset(iter);
 329 //ust//         marker_iter_start(iter);
 330 //ust//         if (!iter->marker) {
 331 //ust//                 /*
 332 //ust//                  * Setting the iter module to -1UL will make sure
 333 //ust//                  * that no module can possibly hold the current marker.
 334 //ust//                  */
 335 //ust//                 iter->module = (void *)-1UL;
 336 //ust//                 return NULL;
 337 //ust//         }
 338 //ust//         return iter->marker;
 339 //ust// }
 340 //ust//
 341 //ust// static void s_stop(struct seq_file *m, void *p)
 342 //ust// {
 343 //ust//         marker_iter_stop(m->private);
 344 //ust// }
 345 //ust//
 346 //ust// static int s_show(struct seq_file *m, void *p)
 347 //ust// {
 348 //ust//         struct marker_iter *iter = m->private;
 349 //ust//
 350 //ust//         seq_printf(m, "channel: %s marker: %s format: \"%s\" state: %d "
 351 //ust//                 "event_id: %hu call: 0x%p probe %s : 0x%p\n",
 352 //ust//                 iter->marker->channel,
 353 //ust//                 iter->marker->name, iter->marker->format,
 354 //ust//                 _imv_read(iter->marker->state),
 355 //ust//                 iter->marker->event_id,
 356 //ust//                 iter->marker->call,
 357 //ust//                 iter->marker->ptype ? "multi" : "single",
 358 //ust//                 iter->marker->ptype ?
 359 //ust//                 (void*)iter->marker->multi : (void*)iter->marker->single.func);
 360 //ust//         return 0;
 361 //ust// }
 362 //ust//
 363 //ust// static const struct seq_operations ltt_seq_op = {
 364 //ust//         .start = s_start,
 365 //ust//         .next = s_next,
 366 //ust//         .stop = s_stop,
 367 //ust//         .show = s_show,
 368 //ust// };
 369 //ust//
 370 //ust// static int ltt_open(struct inode *inode, struct file *file)
 371 //ust// {
 372 //ust//         /*
 373 //ust//          * Iterator kept in m->private.
 374 //ust//          * Restart iteration on all modules between reads because we do not lock
 375 //ust//          * the module mutex between those.
 376 //ust//          */
 377 //ust//         int ret;
 378 //ust//         struct marker_iter *iter;
 379 //ust//
 380 //ust//         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 381 //ust//         if (!iter)
 382 //ust//                 return -ENOMEM;
 383 //ust//
 384 //ust//         ret = seq_open(file, &ltt_seq_op);
 385 //ust//         if (ret == 0)
 386 //ust//                 ((struct seq_file *)file->private_data)->private = iter;
 387 //ust//         else
 388 //ust//                 kfree(iter);
 389 //ust//         return ret;
 390 //ust// }
 391 //ust//
 392 //ust// static struct file_operations ltt_fops = {
 393 //ust//         .write = ltt_write,
 394 //ust//         .open = ltt_open,
 395 //ust//         .read = seq_read,
 396 //ust//         .llseek = seq_lseek,
 397 //ust//         .release = seq_release_private,
 398 //ust// };
 399
 400 static void disconnect_all_markers(void)
 401 {
 402         struct ltt_active_marker *pdata, *tmp;
 403
 404         list_for_each_entry_safe(pdata, tmp, &markers_loaded_list, node) {
 405                 marker_probe_unregister_private_data(pdata->probe->probe_func,
 406                         pdata);
 407                 list_del(&pdata->node);
 408                 free(pdata);
 409         }
 410 }
 411
 412 static char initialized = 0;
 413
 414 void __attribute__((constructor)) init_marker_control(void)
 415 {
 416         if(!initialized) {
 417                 int ret;
 418
 419 //ust// pentry = create_proc_entry("ltt", S_IRUSR|S_IWUSR, NULL);
 420 //ust// if (!pentry)
 421 //ust//         return -EBUSY;
 422 //ust// markers_loaded_cachep = KMEM_CACHE(ltt_active_marker, 0);
 423
 424                 ret = ltt_probe_register(&default_probe);
 425                 BUG_ON(ret);
 426                 ret = ltt_marker_connect("metadata", "core_marker_format",
 427                                          DEFAULT_PROBE);
 428                 BUG_ON(ret);
 429                 ret = ltt_marker_connect("metadata", "core_marker_id", DEFAULT_PROBE);
 430                 BUG_ON(ret);
 431 //ust// pentry->proc_fops = &ltt_fops;
 432
 433                 initialized = 1;
 434         }
 435
 436         return 0;
 437 }
 438 //ust// module_init(marker_control_init);
 439
 440 static void __exit marker_control_exit(void)
 441 {
 442         int ret;
 443
 444 //ust// remove_proc_entry("ltt", NULL);
 445         ret = ltt_marker_disconnect("metadata", "core_marker_format",
 446                                     DEFAULT_PROBE);
 447         BUG_ON(ret);
 448         ret = ltt_marker_disconnect("metadata", "core_marker_id",
 449                                     DEFAULT_PROBE);
 450         BUG_ON(ret);
 451         ret = ltt_probe_unregister(&default_probe);
 452         BUG_ON(ret);
 453         disconnect_all_markers();
 454 //ust// kmem_cache_destroy(markers_loaded_cachep);
 455 //ust// marker_synchronize_unregister();
 456 }
 457 //ust// module_exit(marker_control_exit);
 458
 459 //ust// MODULE_LICENSE("GPL");
 460 //ust// MODULE_AUTHOR("Mathieu Desnoyers");
 461 //ust// MODULE_DESCRIPTION("Linux Trace Toolkit Marker Control");