lttng-context.c

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * lttng-context.c
   4  *
   5  * LTTng trace/channel/event context management.
   6  *
   7  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/list.h>
  12 #include <linux/mutex.h>
  13 #include <linux/slab.h>
  14 #include <wrapper/vmalloc.h>    /* for wrapper_vmalloc_sync_all() */
  15 #include <lttng-events.h>
  16 #include <lttng-tracer.h>
  17
  18 /*
  19  * The filter implementation requires that two consecutive "get" for the
  20  * same context performed by the same thread return the same result.
  21  */
  22
  23 /*
  24  * Static array of contexts, for $ctx filters.
  25  */
  26 struct lttng_ctx *lttng_static_ctx;
  27
  28 int lttng_find_context(struct lttng_ctx *ctx, const char *name)
  29 {
  30         unsigned int i;
  31
  32         for (i = 0; i < ctx->nr_fields; i++) {
  33                 /* Skip allocated (but non-initialized) contexts */
  34                 if (!ctx->fields[i].event_field.name)
  35                         continue;
  36                 if (!strcmp(ctx->fields[i].event_field.name, name))
  37                         return 1;
  38         }
  39         return 0;
  40 }
  41 EXPORT_SYMBOL_GPL(lttng_find_context);
  42
  43 int lttng_get_context_index(struct lttng_ctx *ctx, const char *name)
  44 {
  45         unsigned int i;
  46         const char *subname;
  47
  48         if (!ctx)
  49                 return -1;
  50         if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) {
  51                 subname = name + strlen("$ctx.");
  52         } else {
  53                 subname = name;
  54         }
  55         for (i = 0; i < ctx->nr_fields; i++) {
  56                 /* Skip allocated (but non-initialized) contexts */
  57                 if (!ctx->fields[i].event_field.name)
  58                         continue;
  59                 if (!strcmp(ctx->fields[i].event_field.name, subname))
  60                         return i;
  61         }
  62         return -1;
  63 }
  64 EXPORT_SYMBOL_GPL(lttng_get_context_index);
  65
  66 /*
  67  * Note: as we append context information, the pointer location may change.
  68  */
  69 struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
  70 {
  71         struct lttng_ctx_field *field;
  72         struct lttng_ctx *ctx;
  73
  74         if (!*ctx_p) {
  75                 *ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
  76                 if (!*ctx_p)
  77                         return NULL;
  78                 (*ctx_p)->largest_align = 1;
  79         }
  80         ctx = *ctx_p;
  81         if (ctx->nr_fields + 1 > ctx->allocated_fields) {
  82                 struct lttng_ctx_field *new_fields;
  83
  84                 ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields);
  85                 new_fields = lttng_kvzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL);
  86                 if (!new_fields)
  87                         return NULL;
  88                 if (ctx->fields)
  89                         memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields);
  90                 lttng_kvfree(ctx->fields);
  91                 ctx->fields = new_fields;
  92         }
  93         field = &ctx->fields[ctx->nr_fields];
  94         ctx->nr_fields++;
  95         return field;
  96 }
  97 EXPORT_SYMBOL_GPL(lttng_append_context);
  98
  99 /*
 100  * lttng_context_update() should be called at least once between context
 101  * modification and trace start.
 102  */
 103 void lttng_context_update(struct lttng_ctx *ctx)
 104 {
 105         int i;
 106         size_t largest_align = 8;       /* in bits */
 107
 108         for (i = 0; i < ctx->nr_fields; i++) {
 109                 struct lttng_type *type;
 110                 size_t field_align = 8;
 111
 112                 type = &ctx->fields[i].event_field.type;
 113                 switch (type->atype) {
 114                 case atype_integer:
 115                         field_align = type->u.integer.alignment;
 116                         break;
 117                 case atype_array_nestable:
 118                 {
 119                         const struct lttng_type *nested_type;
 120
 121                         nested_type = type->u.array_nestable.elem_type;
 122                         switch (nested_type->atype) {
 123                         case atype_integer:
 124                                 field_align = nested_type->u.integer.alignment;
 125                                 break;
 126                         case atype_string:
 127                                 break;
 128
 129                         case atype_array_nestable:
 130                         case atype_sequence_nestable:
 131                         case atype_struct_nestable:
 132                         case atype_variant_nestable:
 133                         default:
 134                                 WARN_ON_ONCE(1);
 135                                 break;
 136                         }
 137                         field_align = max_t(size_t, field_align,
 138                                         type->u.array_nestable.alignment);
 139                         break;
 140                 }
 141                 case atype_sequence_nestable:
 142                 {
 143                         const struct lttng_type *nested_type;
 144
 145                         nested_type = type->u.sequence_nestable.elem_type;
 146                         switch (nested_type->atype) {
 147                         case atype_integer:
 148                                 field_align = nested_type->u.integer.alignment;
 149                                 break;
 150
 151                         case atype_string:
 152                                 break;
 153
 154                         case atype_array_nestable:
 155                         case atype_sequence_nestable:
 156                         case atype_struct_nestable:
 157                         case atype_variant_nestable:
 158                         default:
 159                                 WARN_ON_ONCE(1);
 160                                 break;
 161                         }
 162                         field_align = max_t(size_t, field_align,
 163                                         type->u.sequence_nestable.alignment);
 164                         break;
 165                 }
 166                 case atype_string:
 167                         break;
 168
 169                 case atype_struct_nestable:
 170                 case atype_variant_nestable:
 171                         break;
 172
 173                 case atype_enum_nestable:
 174                 default:
 175                         WARN_ON_ONCE(1);
 176                         break;
 177                 }
 178                 largest_align = max_t(size_t, largest_align, field_align);
 179         }
 180         ctx->largest_align = largest_align >> 3;        /* bits to bytes */
 181 }
 182
 183 /*
 184  * Remove last context field.
 185  */
 186 void lttng_remove_context_field(struct lttng_ctx **ctx_p,
 187                                 struct lttng_ctx_field *field)
 188 {
 189         struct lttng_ctx *ctx;
 190
 191         ctx = *ctx_p;
 192         ctx->nr_fields--;
 193         WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field);
 194         memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
 195 }
 196 EXPORT_SYMBOL_GPL(lttng_remove_context_field);
 197
 198 void lttng_destroy_context(struct lttng_ctx *ctx)
 199 {
 200         int i;
 201
 202         if (!ctx)
 203                 return;
 204         for (i = 0; i < ctx->nr_fields; i++) {
 205                 if (ctx->fields[i].destroy)
 206                         ctx->fields[i].destroy(&ctx->fields[i]);
 207         }
 208         lttng_kvfree(ctx->fields);
 209         kfree(ctx);
 210 }
 211
 212 int lttng_context_init(void)
 213 {
 214         int ret;
 215
 216         ret = lttng_add_hostname_to_ctx(&lttng_static_ctx);
 217         if (ret) {
 218                 printk(KERN_WARNING "Cannot add context lttng_add_hostname_to_ctx");
 219         }
 220         ret = lttng_add_nice_to_ctx(&lttng_static_ctx);
 221         if (ret) {
 222                 printk(KERN_WARNING "Cannot add context lttng_add_nice_to_ctx");
 223         }
 224         ret = lttng_add_pid_to_ctx(&lttng_static_ctx);
 225         if (ret) {
 226                 printk(KERN_WARNING "Cannot add context lttng_add_pid_to_ctx");
 227         }
 228         ret = lttng_add_ppid_to_ctx(&lttng_static_ctx);
 229         if (ret) {
 230                 printk(KERN_WARNING "Cannot add context lttng_add_ppid_to_ctx");
 231         }
 232         ret = lttng_add_prio_to_ctx(&lttng_static_ctx);
 233         if (ret) {
 234                 printk(KERN_WARNING "Cannot add context lttng_add_prio_to_ctx");
 235         }
 236         ret = lttng_add_procname_to_ctx(&lttng_static_ctx);
 237         if (ret) {
 238                 printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
 239         }
 240         ret = lttng_add_tid_to_ctx(&lttng_static_ctx);
 241         if (ret) {
 242                 printk(KERN_WARNING "Cannot add context lttng_add_tid_to_ctx");
 243         }
 244         ret = lttng_add_vppid_to_ctx(&lttng_static_ctx);
 245         if (ret) {
 246                 printk(KERN_WARNING "Cannot add context lttng_add_vppid_to_ctx");
 247         }
 248         ret = lttng_add_vtid_to_ctx(&lttng_static_ctx);
 249         if (ret) {
 250                 printk(KERN_WARNING "Cannot add context lttng_add_vtid_to_ctx");
 251         }
 252         ret = lttng_add_vpid_to_ctx(&lttng_static_ctx);
 253         if (ret) {
 254                 printk(KERN_WARNING "Cannot add context lttng_add_vpid_to_ctx");
 255         }
 256         ret = lttng_add_cpu_id_to_ctx(&lttng_static_ctx);
 257         if (ret) {
 258                 printk(KERN_WARNING "Cannot add context lttng_add_cpu_id_to_ctx");
 259         }
 260         ret = lttng_add_interruptible_to_ctx(&lttng_static_ctx);
 261         if (ret) {
 262                 printk(KERN_WARNING "Cannot add context lttng_add_interruptible_to_ctx");
 263         }
 264         ret = lttng_add_need_reschedule_to_ctx(&lttng_static_ctx);
 265         if (ret) {
 266                 printk(KERN_WARNING "Cannot add context lttng_add_need_reschedule_to_ctx");
 267         }
 268         ret = lttng_add_preemptible_to_ctx(&lttng_static_ctx);
 269         if (ret && ret != -ENOSYS) {
 270                 printk(KERN_WARNING "Cannot add context lttng_add_preemptible_to_ctx");
 271         }
 272         ret = lttng_add_migratable_to_ctx(&lttng_static_ctx);
 273         if (ret && ret != -ENOSYS) {
 274                 printk(KERN_WARNING "Cannot add context lttng_add_migratable_to_ctx");
 275         }
 276         ret = lttng_add_cgroup_ns_to_ctx(&lttng_static_ctx);
 277         if (ret && ret != -ENOSYS) {
 278                 printk(KERN_WARNING "Cannot add context lttng_add_cgroup_ns_to_ctx");
 279         }
 280         ret = lttng_add_ipc_ns_to_ctx(&lttng_static_ctx);
 281         if (ret && ret != -ENOSYS) {
 282                 printk(KERN_WARNING "Cannot add context lttng_add_ipc_ns_to_ctx");
 283         }
 284         ret = lttng_add_mnt_ns_to_ctx(&lttng_static_ctx);
 285         if (ret && ret != -ENOSYS) {
 286                 printk(KERN_WARNING "Cannot add context lttng_add_mnt_ns_to_ctx");
 287         }
 288         ret = lttng_add_net_ns_to_ctx(&lttng_static_ctx);
 289         if (ret && ret != -ENOSYS) {
 290                 printk(KERN_WARNING "Cannot add context lttng_add_net_ns_to_ctx");
 291         }
 292         ret = lttng_add_pid_ns_to_ctx(&lttng_static_ctx);
 293         if (ret && ret != -ENOSYS) {
 294                 printk(KERN_WARNING "Cannot add context lttng_add_pid_ns_to_ctx");
 295         }
 296         ret = lttng_add_user_ns_to_ctx(&lttng_static_ctx);
 297         if (ret && ret != -ENOSYS) {
 298                 printk(KERN_WARNING "Cannot add context lttng_add_user_ns_to_ctx");
 299         }
 300         ret = lttng_add_uts_ns_to_ctx(&lttng_static_ctx);
 301         if (ret && ret != -ENOSYS) {
 302                 printk(KERN_WARNING "Cannot add context lttng_add_uts_ns_to_ctx");
 303         }
 304         /* TODO: perf counters for filtering */
 305         return 0;
 306 }
 307
 308 void lttng_context_exit(void)
 309 {
 310         lttng_destroy_context(lttng_static_ctx);
 311         lttng_static_ctx = NULL;
 312 }