| 1 | /* |
| 2 | * Copyright (C) 2007 Mathieu Desnoyers |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU Lesser General Public |
| 6 | * License as published by the Free Software Foundation; either |
| 7 | * version 2.1 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * This library 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 GNU |
| 12 | * Lesser General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public |
| 15 | * License along with this library; if not, write to the Free Software |
| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | * |
| 18 | */ |
| 19 | |
| 20 | /* This file contains a high-level API for activating and deactivating ust_markers, |
| 21 | * and making sure ust_markers in a given library can be released when the library |
| 22 | * is unloaded. |
| 23 | */ |
| 24 | |
| 25 | #include <ctype.h> |
| 26 | #include <stdlib.h> |
| 27 | |
| 28 | #include "tracer.h" |
| 29 | #include "usterr_signal_safe.h" |
| 30 | |
| 31 | #define DEFAULT_CHANNEL "cpu" |
| 32 | #define DEFAULT_PROBE "default" |
| 33 | |
| 34 | static int initialized; |
| 35 | |
| 36 | CDS_LIST_HEAD(probes_list); |
| 37 | |
| 38 | /* |
| 39 | * Mutex protecting the probe slab cache. |
| 40 | * Nests inside the traces mutex. |
| 41 | */ |
| 42 | DEFINE_MUTEX(probes_mutex); |
| 43 | |
| 44 | struct ltt_available_probe default_probe = { |
| 45 | .name = "default", |
| 46 | .format = NULL, |
| 47 | .probe_func = ltt_vtrace, |
| 48 | .callbacks[0] = ltt_serialize_data, |
| 49 | }; |
| 50 | |
| 51 | //ust//static struct kmem_cache *ust_markers_loaded_cachep; |
| 52 | static CDS_LIST_HEAD(ust_markers_loaded_list); |
| 53 | /* |
| 54 | * List sorted by name strcmp order. |
| 55 | */ |
| 56 | static CDS_LIST_HEAD(probes_registered_list); |
| 57 | |
| 58 | static struct ltt_available_probe *get_probe_from_name(const char *pname) |
| 59 | { |
| 60 | struct ltt_available_probe *iter; |
| 61 | int comparison, found = 0; |
| 62 | |
| 63 | if (!pname) |
| 64 | pname = DEFAULT_PROBE; |
| 65 | cds_list_for_each_entry(iter, &probes_registered_list, node) { |
| 66 | comparison = strcmp(pname, iter->name); |
| 67 | if (!comparison) |
| 68 | found = 1; |
| 69 | if (comparison <= 0) |
| 70 | break; |
| 71 | } |
| 72 | if (found) |
| 73 | return iter; |
| 74 | else |
| 75 | return NULL; |
| 76 | } |
| 77 | |
| 78 | /* (unused) |
| 79 | static char *skip_spaces(char *buf) |
| 80 | { |
| 81 | while (*buf != '\0' && isspace(*buf)) |
| 82 | buf++; |
| 83 | return buf; |
| 84 | } |
| 85 | |
| 86 | static char *skip_nonspaces(char *buf) |
| 87 | { |
| 88 | while (*buf != '\0' && !isspace(*buf)) |
| 89 | buf++; |
| 90 | return buf; |
| 91 | } |
| 92 | |
| 93 | static void get_ust_marker_string(char *buf, char **start, |
| 94 | char **end) |
| 95 | { |
| 96 | *start = skip_spaces(buf); |
| 97 | *end = skip_nonspaces(*start); |
| 98 | **end = '\0'; |
| 99 | } |
| 100 | */ |
| 101 | |
| 102 | int ltt_probe_register(struct ltt_available_probe *pdata) |
| 103 | { |
| 104 | int ret = 0; |
| 105 | int comparison; |
| 106 | struct ltt_available_probe *iter; |
| 107 | |
| 108 | pthread_mutex_lock(&probes_mutex); |
| 109 | cds_list_for_each_entry_reverse(iter, &probes_registered_list, node) { |
| 110 | comparison = strcmp(pdata->name, iter->name); |
| 111 | if (!comparison) { |
| 112 | ret = -EBUSY; |
| 113 | goto end; |
| 114 | } else if (comparison > 0) { |
| 115 | /* We belong to the location right after iter. */ |
| 116 | cds_list_add(&pdata->node, &iter->node); |
| 117 | goto end; |
| 118 | } |
| 119 | } |
| 120 | /* Should be added at the head of the list */ |
| 121 | cds_list_add(&pdata->node, &probes_registered_list); |
| 122 | end: |
| 123 | pthread_mutex_unlock(&probes_mutex); |
| 124 | return ret; |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * Called when a probe does not want to be called anymore. |
| 129 | */ |
| 130 | int ltt_probe_unregister(struct ltt_available_probe *pdata) |
| 131 | { |
| 132 | int ret = 0; |
| 133 | struct ltt_active_ust_marker *amark, *tmp; |
| 134 | |
| 135 | pthread_mutex_lock(&probes_mutex); |
| 136 | cds_list_for_each_entry_safe(amark, tmp, &ust_markers_loaded_list, node) { |
| 137 | if (amark->probe == pdata) { |
| 138 | ret = ust_marker_probe_unregister_private_data( |
| 139 | pdata->probe_func, amark); |
| 140 | if (ret) |
| 141 | goto end; |
| 142 | cds_list_del(&amark->node); |
| 143 | free(amark); |
| 144 | } |
| 145 | } |
| 146 | cds_list_del(&pdata->node); |
| 147 | end: |
| 148 | pthread_mutex_unlock(&probes_mutex); |
| 149 | return ret; |
| 150 | } |
| 151 | |
| 152 | /* |
| 153 | * Connect ust_marker "mname" to probe "pname". |
| 154 | * Only allow _only_ probe instance to be connected to a ust_marker. |
| 155 | */ |
| 156 | int ltt_ust_marker_connect(const char *channel, const char *mname, |
| 157 | const char *pname) |
| 158 | |
| 159 | { |
| 160 | int ret; |
| 161 | struct ltt_active_ust_marker *pdata; |
| 162 | struct ltt_available_probe *probe; |
| 163 | |
| 164 | ltt_lock_traces(); |
| 165 | pthread_mutex_lock(&probes_mutex); |
| 166 | probe = get_probe_from_name(pname); |
| 167 | if (!probe) { |
| 168 | ret = -ENOENT; |
| 169 | goto end; |
| 170 | } |
| 171 | pdata = ust_marker_get_private_data(channel, mname, probe->probe_func, 0); |
| 172 | if (pdata && !IS_ERR(pdata)) { |
| 173 | ret = -EEXIST; |
| 174 | goto end; |
| 175 | } |
| 176 | pdata = zmalloc(sizeof(struct ltt_active_ust_marker)); |
| 177 | if (!pdata) { |
| 178 | ret = -ENOMEM; |
| 179 | goto end; |
| 180 | } |
| 181 | pdata->probe = probe; |
| 182 | /* |
| 183 | * ID has priority over channel in case of conflict. |
| 184 | */ |
| 185 | ret = ust_marker_probe_register(channel, mname, NULL, |
| 186 | probe->probe_func, pdata); |
| 187 | if (ret) |
| 188 | free(pdata); |
| 189 | else |
| 190 | cds_list_add(&pdata->node, &ust_markers_loaded_list); |
| 191 | end: |
| 192 | pthread_mutex_unlock(&probes_mutex); |
| 193 | ltt_unlock_traces(); |
| 194 | return ret; |
| 195 | } |
| 196 | |
| 197 | /* |
| 198 | * Disconnect ust_marker "mname", probe "pname". |
| 199 | */ |
| 200 | int ltt_ust_marker_disconnect(const char *channel, const char *mname, |
| 201 | const char *pname) |
| 202 | { |
| 203 | struct ltt_active_ust_marker *pdata; |
| 204 | struct ltt_available_probe *probe; |
| 205 | int ret = 0; |
| 206 | |
| 207 | pthread_mutex_lock(&probes_mutex); |
| 208 | probe = get_probe_from_name(pname); |
| 209 | if (!probe) { |
| 210 | ret = -ENOENT; |
| 211 | goto end; |
| 212 | } |
| 213 | pdata = ust_marker_get_private_data(channel, mname, probe->probe_func, 0); |
| 214 | if (IS_ERR(pdata)) { |
| 215 | ret = PTR_ERR(pdata); |
| 216 | goto end; |
| 217 | } else if (!pdata) { |
| 218 | /* |
| 219 | * Not registered by us. |
| 220 | */ |
| 221 | ret = -EPERM; |
| 222 | goto end; |
| 223 | } |
| 224 | ret = ust_marker_probe_unregister(channel, mname, probe->probe_func, pdata); |
| 225 | if (ret) |
| 226 | goto end; |
| 227 | else { |
| 228 | cds_list_del(&pdata->node); |
| 229 | free(pdata); |
| 230 | } |
| 231 | end: |
| 232 | pthread_mutex_unlock(&probes_mutex); |
| 233 | return ret; |
| 234 | } |
| 235 | |
| 236 | static void disconnect_all_ust_markers(void) |
| 237 | { |
| 238 | struct ltt_active_ust_marker *pdata, *tmp; |
| 239 | |
| 240 | cds_list_for_each_entry_safe(pdata, tmp, &ust_markers_loaded_list, node) { |
| 241 | ust_marker_probe_unregister_private_data(pdata->probe->probe_func, |
| 242 | pdata); |
| 243 | cds_list_del(&pdata->node); |
| 244 | free(pdata); |
| 245 | } |
| 246 | } |
| 247 | |
| 248 | void __attribute__((constructor)) init_ust_marker_control(void) |
| 249 | { |
| 250 | if (!initialized) { |
| 251 | int ret; |
| 252 | |
| 253 | init_ust_marker(); |
| 254 | ret = ltt_probe_register(&default_probe); |
| 255 | BUG_ON(ret); |
| 256 | ret = ltt_ust_marker_connect("metadata", "core_marker_format", |
| 257 | DEFAULT_PROBE); |
| 258 | BUG_ON(ret); |
| 259 | ret = ltt_ust_marker_connect("metadata", "core_marker_id", DEFAULT_PROBE); |
| 260 | BUG_ON(ret); |
| 261 | initialized = 1; |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | static void __attribute__((destructor)) ust_marker_control_exit(void) |
| 266 | { |
| 267 | int ret; |
| 268 | |
| 269 | ret = ltt_ust_marker_disconnect("metadata", "core_marker_format", |
| 270 | DEFAULT_PROBE); |
| 271 | BUG_ON(ret); |
| 272 | ret = ltt_ust_marker_disconnect("metadata", "core_marker_id", |
| 273 | DEFAULT_PROBE); |
| 274 | BUG_ON(ret); |
| 275 | ret = ltt_probe_unregister(&default_probe); |
| 276 | BUG_ON(ret); |
| 277 | disconnect_all_ust_markers(); |
| 278 | ust_marker_synchronize_unregister(); |
| 279 | } |