| 1 | /* |
| 2 | * Copyright (C) 2007 Mathieu Desnoyers |
| 3 | * |
| 4 | * Dual LGPL v2.1/GPL v2 license. |
| 5 | */ |
| 6 | |
| 7 | #include <linux/module.h> |
| 8 | #include <linux/stat.h> |
| 9 | #include <linux/vmalloc.h> |
| 10 | #include <linux/marker.h> |
| 11 | #include <linux/uaccess.h> |
| 12 | #include <linux/string.h> |
| 13 | #include <linux/ctype.h> |
| 14 | #include <linux/list.h> |
| 15 | #include <linux/mutex.h> |
| 16 | #include <linux/seq_file.h> |
| 17 | #include <linux/slab.h> |
| 18 | |
| 19 | #include "ltt-tracer.h" |
| 20 | |
| 21 | #define DEFAULT_CHANNEL "cpu" |
| 22 | #define DEFAULT_PROBE "default" |
| 23 | |
| 24 | LIST_HEAD(probes_list); |
| 25 | |
| 26 | /* |
| 27 | * Mutex protecting the probe slab cache. |
| 28 | * Nests inside the traces mutex. |
| 29 | */ |
| 30 | DEFINE_MUTEX(probes_mutex); |
| 31 | |
| 32 | struct ltt_available_probe default_probe = { |
| 33 | .name = "default", |
| 34 | .format = NULL, |
| 35 | .probe_func = ltt_vtrace, |
| 36 | .callbacks[0] = ltt_serialize_data, |
| 37 | }; |
| 38 | |
| 39 | static struct kmem_cache *markers_loaded_cachep; |
| 40 | static LIST_HEAD(markers_loaded_list); |
| 41 | /* |
| 42 | * List sorted by name strcmp order. |
| 43 | */ |
| 44 | static LIST_HEAD(probes_registered_list); |
| 45 | |
| 46 | static struct ltt_available_probe *get_probe_from_name(const char *pname) |
| 47 | { |
| 48 | struct ltt_available_probe *iter; |
| 49 | int comparison, found = 0; |
| 50 | |
| 51 | if (!pname) |
| 52 | pname = DEFAULT_PROBE; |
| 53 | list_for_each_entry(iter, &probes_registered_list, node) { |
| 54 | comparison = strcmp(pname, iter->name); |
| 55 | if (!comparison) |
| 56 | found = 1; |
| 57 | if (comparison <= 0) |
| 58 | break; |
| 59 | } |
| 60 | if (found) |
| 61 | return iter; |
| 62 | else |
| 63 | return NULL; |
| 64 | } |
| 65 | |
| 66 | int ltt_probe_register(struct ltt_available_probe *pdata) |
| 67 | { |
| 68 | int ret = 0; |
| 69 | int comparison; |
| 70 | struct ltt_available_probe *iter; |
| 71 | |
| 72 | mutex_lock(&probes_mutex); |
| 73 | list_for_each_entry_reverse(iter, &probes_registered_list, node) { |
| 74 | comparison = strcmp(pdata->name, iter->name); |
| 75 | if (!comparison) { |
| 76 | ret = -EBUSY; |
| 77 | goto end; |
| 78 | } else if (comparison > 0) { |
| 79 | /* We belong to the location right after iter. */ |
| 80 | list_add(&pdata->node, &iter->node); |
| 81 | goto end; |
| 82 | } |
| 83 | } |
| 84 | /* Should be added at the head of the list */ |
| 85 | list_add(&pdata->node, &probes_registered_list); |
| 86 | end: |
| 87 | mutex_unlock(&probes_mutex); |
| 88 | return ret; |
| 89 | } |
| 90 | EXPORT_SYMBOL_GPL(ltt_probe_register); |
| 91 | |
| 92 | /* |
| 93 | * Called when a probe does not want to be called anymore. |
| 94 | */ |
| 95 | int ltt_probe_unregister(struct ltt_available_probe *pdata) |
| 96 | { |
| 97 | int ret = 0; |
| 98 | struct ltt_active_marker *amark, *tmp; |
| 99 | |
| 100 | mutex_lock(&probes_mutex); |
| 101 | list_for_each_entry_safe(amark, tmp, &markers_loaded_list, node) { |
| 102 | if (amark->probe == pdata) { |
| 103 | ret = marker_probe_unregister_private_data( |
| 104 | pdata->probe_func, amark); |
| 105 | if (ret) |
| 106 | goto end; |
| 107 | list_del(&amark->node); |
| 108 | kmem_cache_free(markers_loaded_cachep, amark); |
| 109 | } |
| 110 | } |
| 111 | list_del(&pdata->node); |
| 112 | end: |
| 113 | mutex_unlock(&probes_mutex); |
| 114 | return ret; |
| 115 | } |
| 116 | EXPORT_SYMBOL_GPL(ltt_probe_unregister); |
| 117 | |
| 118 | /* |
| 119 | * Connect marker "mname" to probe "pname". |
| 120 | * Only allow _only_ probe instance to be connected to a marker. |
| 121 | */ |
| 122 | int ltt_marker_connect(const char *channel, const char *mname, |
| 123 | const char *pname) |
| 124 | |
| 125 | { |
| 126 | int ret; |
| 127 | struct ltt_active_marker *pdata; |
| 128 | struct ltt_available_probe *probe; |
| 129 | |
| 130 | ltt_lock_traces(); |
| 131 | mutex_lock(&probes_mutex); |
| 132 | probe = get_probe_from_name(pname); |
| 133 | if (!probe) { |
| 134 | ret = -ENOENT; |
| 135 | goto end; |
| 136 | } |
| 137 | pdata = marker_get_private_data(channel, mname, probe->probe_func, 0); |
| 138 | if (pdata && !IS_ERR(pdata)) { |
| 139 | ret = -EEXIST; |
| 140 | goto end; |
| 141 | } |
| 142 | pdata = kmem_cache_zalloc(markers_loaded_cachep, GFP_KERNEL); |
| 143 | if (!pdata) { |
| 144 | ret = -ENOMEM; |
| 145 | goto end; |
| 146 | } |
| 147 | pdata->probe = probe; |
| 148 | /* |
| 149 | * ID has priority over channel in case of conflict. |
| 150 | */ |
| 151 | ret = marker_probe_register(channel, mname, NULL, |
| 152 | probe->probe_func, pdata); |
| 153 | if (ret) |
| 154 | kmem_cache_free(markers_loaded_cachep, pdata); |
| 155 | else |
| 156 | list_add(&pdata->node, &markers_loaded_list); |
| 157 | end: |
| 158 | mutex_unlock(&probes_mutex); |
| 159 | ltt_unlock_traces(); |
| 160 | return ret; |
| 161 | } |
| 162 | EXPORT_SYMBOL_GPL(ltt_marker_connect); |
| 163 | |
| 164 | /* |
| 165 | * Disconnect marker "mname", probe "pname". |
| 166 | */ |
| 167 | int ltt_marker_disconnect(const char *channel, const char *mname, |
| 168 | const char *pname) |
| 169 | { |
| 170 | struct ltt_active_marker *pdata; |
| 171 | struct ltt_available_probe *probe; |
| 172 | int ret = 0; |
| 173 | |
| 174 | mutex_lock(&probes_mutex); |
| 175 | probe = get_probe_from_name(pname); |
| 176 | if (!probe) { |
| 177 | ret = -ENOENT; |
| 178 | goto end; |
| 179 | } |
| 180 | pdata = marker_get_private_data(channel, mname, probe->probe_func, 0); |
| 181 | if (IS_ERR(pdata)) { |
| 182 | ret = PTR_ERR(pdata); |
| 183 | goto end; |
| 184 | } else if (!pdata) { |
| 185 | /* |
| 186 | * Not registered by us. |
| 187 | */ |
| 188 | ret = -EPERM; |
| 189 | goto end; |
| 190 | } |
| 191 | ret = marker_probe_unregister(channel, mname, probe->probe_func, pdata); |
| 192 | if (ret) |
| 193 | goto end; |
| 194 | else { |
| 195 | list_del(&pdata->node); |
| 196 | kmem_cache_free(markers_loaded_cachep, pdata); |
| 197 | } |
| 198 | end: |
| 199 | mutex_unlock(&probes_mutex); |
| 200 | return ret; |
| 201 | } |
| 202 | EXPORT_SYMBOL_GPL(ltt_marker_disconnect); |
| 203 | |
| 204 | static void disconnect_all_markers(void) |
| 205 | { |
| 206 | struct ltt_active_marker *pdata, *tmp; |
| 207 | |
| 208 | list_for_each_entry_safe(pdata, tmp, &markers_loaded_list, node) { |
| 209 | marker_probe_unregister_private_data(pdata->probe->probe_func, |
| 210 | pdata); |
| 211 | list_del(&pdata->node); |
| 212 | kmem_cache_free(markers_loaded_cachep, pdata); |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | static int __init marker_control_init(void) |
| 217 | { |
| 218 | int ret; |
| 219 | |
| 220 | markers_loaded_cachep = KMEM_CACHE(ltt_active_marker, 0); |
| 221 | |
| 222 | ret = ltt_probe_register(&default_probe); |
| 223 | BUG_ON(ret); |
| 224 | ret = ltt_marker_connect("metadata", "core_marker_format", |
| 225 | DEFAULT_PROBE); |
| 226 | BUG_ON(ret); |
| 227 | ret = ltt_marker_connect("metadata", "core_marker_id", DEFAULT_PROBE); |
| 228 | BUG_ON(ret); |
| 229 | |
| 230 | return 0; |
| 231 | } |
| 232 | module_init(marker_control_init); |
| 233 | |
| 234 | static void __exit marker_control_exit(void) |
| 235 | { |
| 236 | int ret; |
| 237 | |
| 238 | ret = ltt_marker_disconnect("metadata", "core_marker_format", |
| 239 | DEFAULT_PROBE); |
| 240 | BUG_ON(ret); |
| 241 | ret = ltt_marker_disconnect("metadata", "core_marker_id", |
| 242 | DEFAULT_PROBE); |
| 243 | BUG_ON(ret); |
| 244 | ret = ltt_probe_unregister(&default_probe); |
| 245 | BUG_ON(ret); |
| 246 | disconnect_all_markers(); |
| 247 | kmem_cache_destroy(markers_loaded_cachep); |
| 248 | marker_synchronize_unregister(); |
| 249 | } |
| 250 | module_exit(marker_control_exit); |
| 251 | |
| 252 | MODULE_LICENSE("GPL and additional rights"); |
| 253 | MODULE_AUTHOR("Mathieu Desnoyers"); |
| 254 | MODULE_DESCRIPTION("Linux Trace Toolkit Marker Control"); |