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pbx.c: Simplify ast_context memory management. 

Allocate all of the ast_context's character data in the structure's
flexible array member and eliminate the clunky fake_context. This will
simplify future changes to ast_context.

Change-Id: I98357de75d8ac2b3c4c9f201223632e6901021ea
This commit is contained in:
Sean Bright 2022-07-05 11:24:58 -04:00 committed by Kevin Harwell
parent dd0badf16b
commit a0c3eb3b08
1 changed files with 48 additions and 49 deletions
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97
main/pbx.c
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@ -280,21 +280,29 @@ struct scoreboard /* make sure all fields are 0 before calling new_find_extensi
struct ast_exten *exten;
};
/*! \brief ast_context: An extension context - must remain in sync with fake_context */
/*! \brief ast_context: An extension context */
struct ast_context {
ast_rwlock_t lock; /*!< A lock to prevent multiple threads from clobbering the context */
struct ast_exten *root; /*!< The root of the list of extensions */
struct ast_hashtab *root_table; /*!< For exact matches on the extensions in the pattern tree, and for traversals of the pattern_tree */
struct match_char *pattern_tree; /*!< A tree to speed up extension pattern matching */
struct ast_context *next; /*!< Link them together */
struct ast_includes includes; /*!< Include other contexts */
struct ast_ignorepats ignorepats; /*!< Patterns for which to continue playing dialtone */
struct ast_sws alts; /*!< Alternative switches */
char *registrar; /*!< Registrar -- make sure you malloc this, as the registrar may have to survive module unloads */
int refcount; /*!< each module that would have created this context should inc/dec this as appropriate */
int autohints; /*!< Whether autohints support is enabled or not */
ast_mutex_t macrolock; /*!< A lock to implement "exclusive" macros - held whilst a call is executing in the macro */
char name[0]; /*!< Name of the context */
const char *name;
const char *registrar;
ast_rwlock_t lock; /*!< A lock to prevent multiple threads from clobbering the context */
struct ast_exten *root; /*!< The root of the list of extensions */
struct ast_hashtab *root_table; /*!< For exact matches on the extensions in the pattern tree, and for traversals of the pattern_tree */
struct match_char *pattern_tree; /*!< A tree to speed up extension pattern matching */
struct ast_context *next; /*!< Link them together */
struct ast_includes includes; /*!< Include other contexts */
struct ast_ignorepats ignorepats; /*!< Patterns for which to continue playing dialtone */
struct ast_sws alts; /*!< Alternative switches */
int refcount; /*!< each module that would have created this context should inc/dec this as appropriate */
int autohints; /*!< Whether autohints support is enabled or not */
ast_mutex_t macrolock; /*!< A lock to implement "exclusive" macros - held whilst a call is executing in the macro */
/*!
* Buffer to hold the name & registrar character data.
*
* The context name *must* be stored first in this buffer.
*/
char data[];
};
/*! \brief ast_state_cb: An extension state notify register item */
@ -2429,35 +2437,18 @@ int ast_extension_close(const char *pattern, const char *data, int needmore)
return extension_match_core(pattern, data, needmore);
}
/* This structure must remain in sync with ast_context for proper hashtab matching */
struct fake_context /* this struct is purely for matching in the hashtab */
{
ast_rwlock_t lock;
struct ast_exten *root;
struct ast_hashtab *root_table;
struct match_char *pattern_tree;
struct ast_context *next;
struct ast_includes includes;
struct ast_ignorepats ignorepats;
struct ast_sws alts;
const char *registrar;
int refcount;
int autohints;
ast_mutex_t macrolock;
char name[256];
};
struct ast_context *ast_context_find(const char *name)
{
struct ast_context *tmp;
struct fake_context item;
struct ast_context item = {
.name = name,
};
if (!name) {
return NULL;
}
ast_rdlock_contexts();
if (contexts_table) {
ast_copy_string(item.name, name, sizeof(item.name));
tmp = ast_hashtab_lookup(contexts_table, &item);
} else {
tmp = NULL;
@ -2768,7 +2759,10 @@ struct ast_exten *pbx_find_extension(struct ast_channel *chan,
return NULL;
}
}
q->incstack[q->stacklen++] = tmp->name; /* Setup the stack */
/* Technically we should be using tmp->name here, but if we used that we
* would have to cast away the constness of the 'name' pointer and I do
* not want to do that. */
q->incstack[q->stacklen++] = tmp->data; /* Setup the stack */
/* Now try any includes we have in this context */
for (idx = 0; idx < ast_context_includes_count(tmp); idx++) {
const struct ast_include *i = ast_context_includes_get(tmp, idx);
@ -4806,9 +4800,9 @@ void pbx_set_overrideswitch(const char *newval)
*/
static struct ast_context *find_context(const char *context)
{
struct fake_context item;
ast_copy_string(item.name, context, sizeof(item.name));
struct ast_context item = {
.name = context,
};
return ast_hashtab_lookup(contexts_table, &item);
}
@ -4821,9 +4815,9 @@ static struct ast_context *find_context(const char *context)
static struct ast_context *find_context_locked(const char *context)
{
struct ast_context *c;
struct fake_context item;
ast_copy_string(item.name, context, sizeof(item.name));
struct ast_context item = {
.name = context,
};
ast_rdlock_contexts();
c = ast_hashtab_lookup(contexts_table, &item);
@ -6199,8 +6193,12 @@ void unreference_cached_app(struct ast_app *app)
struct ast_context *ast_context_find_or_create(struct ast_context **extcontexts, struct ast_hashtab *exttable, const char *name, const char *registrar)
{
struct ast_context *tmp, **local_contexts;
struct fake_context search;
int length = sizeof(struct ast_context) + strlen(name) + 1;
struct ast_context search = {
.name = name,
};
size_t name_bytes = strlen(name);
size_t registrar_bytes = strlen(registrar);
int length = sizeof(struct ast_context) + name_bytes + registrar_bytes + 2;
if (!contexts_table) {
/* Protect creation of contexts_table from reentrancy. */
@ -6216,7 +6214,6 @@ struct ast_context *ast_context_find_or_create(struct ast_context **extcontexts,
ast_unlock_contexts();
}
ast_copy_string(search.name, name, sizeof(search.name));
if (!extcontexts) {
ast_rdlock_contexts();
local_contexts = &contexts;
@ -6238,14 +6235,19 @@ struct ast_context *ast_context_find_or_create(struct ast_context **extcontexts,
if ((tmp = ast_calloc(1, length))) {
ast_rwlock_init(&tmp->lock);
ast_mutex_init(&tmp->macrolock);
strcpy(tmp->name, name);
tmp->name = memcpy(&tmp->data[0], name, name_bytes);
tmp->registrar = memcpy(&tmp->data[name_bytes + 1], registrar, registrar_bytes);
tmp->root = NULL;
tmp->root_table = NULL;
tmp->registrar = ast_strdup(registrar);
AST_VECTOR_INIT(&tmp->includes, 0);
AST_VECTOR_INIT(&tmp->ignorepats, 0);
AST_VECTOR_INIT(&tmp->alts, 0);
tmp->refcount = 1;
/* The context 'name' must be stored at the beginning of 'data.' The
* order of subsequent strings (currently only 'registrar') is not
* relevant. */
ast_assert(tmp->name == &tmp->data[0]);
} else {
ast_log(LOG_ERROR, "Danger! We failed to allocate a context for %s!\n", name);
if (!extcontexts) {
@ -8072,9 +8074,6 @@ static void __ast_internal_context_destroy( struct ast_context *con)
AST_VECTOR_CALLBACK_VOID(&tmp->alts, sw_free);
AST_VECTOR_FREE(&tmp->alts);
if (tmp->registrar)
ast_free(tmp->registrar);
/* destroy the hash tabs */
if (tmp->root_table) {
ast_hashtab_destroy(tmp->root_table, 0);