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Improved and portable ast_log recursion avoidance

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This introduces a new logger routine ast_log_safe.  This routine should be
used for all error messages in code that can be run as a result of ast_log.
ast_log_safe does nothing if run recursively.  All error logging in
astobj2.c, strings.c and utils.h have been switched to ast_log_safe.

This required adding support for raw threadstorage.  This provides direct
access to the void* pointer in threadstorage.  In ast_log_safe, NULL is used
to signify that this thread is not already running ast_log_safe, (void*)1 when
it is already running.  This was done since it's critical that ast_log_safe
do nothing that could log during recursion checking.

ASTERISK-24155 #close
Reported by: Timo Teräs
Review: https://reviewboard.asterisk.org/r/4502/
........

Merged revisions 433522 from http://svn.asterisk.org/svn/asterisk/branches/11
........

Merged revisions 433523 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@433524 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Corey Farrell
2015-03-27 07:12:25 +00:00
parent 554eb74516
commit 28e3bd0af7
7 changed files with 83 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
include/asterisk/logger.h
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@@ -62,6 +62,17 @@ extern "C" {
void ast_log(int level, const char *file, int line, const char *function, const char *fmt, ...)
__attribute__((format(printf, 5, 6)));
/*!
* \brief Used for sending a log message with protection against recursion.
*
* \note This function should be used by all error messages that might be directly
* or indirectly caused by logging.
*
* \see ast_log for documentation on the parameters.
*/
void ast_log_safe(int level, const char *file, int line, const char *function, const char *fmt, ...)
__attribute__((format(printf, 5, 6)));
/* XXX needs documentation */
typedef unsigned int ast_callid;

40
include/asterisk/threadstorage.h
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@@ -84,6 +84,8 @@ void __ast_threadstorage_object_replace(void *key_old, void *key_new, size_t len
AST_THREADSTORAGE_CUSTOM_SCOPE(name, NULL, ast_free_ptr,)
#define AST_THREADSTORAGE_EXTERNAL(name) \
extern struct ast_threadstorage name
#define AST_THREADSTORAGE_RAW(name) \
AST_THREADSTORAGE_CUSTOM_SCOPE(name, NULL, NULL,)
/*!
* \brief Define a thread storage variable, with custom initialization and cleanup
@@ -216,4 +218,42 @@ void *__ast_threadstorage_get(struct ast_threadstorage *ts, size_t init_size, co
#define ast_threadstorage_get(ts, init_size) __ast_threadstorage_get(ts, init_size, __FILE__, __PRETTY_FUNCTION__, __LINE__)
#endif /* defined(DEBUG_THREADLOCALS) */
/*!
* \brief Retrieve a raw pointer from threadstorage.
* \param ts Threadstorage object to operate on.
*
* \return A pointer associated with the current thread, NULL
* if no pointer is associated yet.
*
* \note This should only be used on threadstorage declared
* by AST_THREADSTORAGE_RAW unless you really know what
* you are doing.
*/
AST_INLINE_API(
void *ast_threadstorage_get_ptr(struct ast_threadstorage *ts),
{
pthread_once(&ts->once, ts->key_init);
return pthread_getspecific(ts->key);
}
)
/*!
* \brief Set a raw pointer from threadstorage.
* \param ts Threadstorage object to operate on.
*
* \retval 0 Success
* \retval non-zero Failure
*
* \note This should only be used on threadstorage declared
* by AST_THREADSTORAGE_RAW unless you really know what
* you are doing.
*/
AST_INLINE_API(
int ast_threadstorage_set_ptr(struct ast_threadstorage *ts, void *ptr),
{
pthread_once(&ts->once, ts->key_init);
return pthread_setspecific(ts->key, ptr);
}
)
#endif /* ASTERISK_THREADSTORAGE_H */

21
include/asterisk/utils.h
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@@ -25,7 +25,6 @@
#include "asterisk/network.h"
#include <execinfo.h>
#include <time.h> /* we want to override localtime_r */
#include <unistd.h>
#include <string.h>
@@ -526,26 +525,8 @@ long int ast_random(void);
#define ast_free free
#define ast_free_ptr ast_free
/*
* This buffer is in static memory. We never intend to read it,
* nor do we care about multiple threads writing to it at the
* same time. We only want to know if we're recursing too deep
* already. 60 entries should be more than enough. Function
* call depth rarely exceeds 20 or so.
*/
#define _AST_MEM_BACKTRACE_BUFLEN 60
extern void *_ast_mem_backtrace_buffer[_AST_MEM_BACKTRACE_BUFLEN];
/*
* Ok, this sucks. But if we're already out of mem, we don't
* want the logger to create infinite recursion (and a crash).
*/
#define MALLOC_FAILURE_MSG \
do { \
if (backtrace(_ast_mem_backtrace_buffer, _AST_MEM_BACKTRACE_BUFLEN) < _AST_MEM_BACKTRACE_BUFLEN) { \
ast_log(LOG_ERROR, "Memory Allocation Failure in function %s at line %d of %s\n", func, lineno, file); \
} \
} while (0)
ast_log_safe(LOG_ERROR, "Memory Allocation Failure in function %s at line %d of %s\n", func, lineno, file)
/*!
* \brief A wrapper for malloc()

3
main/astobj2.c
View File

@@ -36,6 +36,9 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/cli.h"
#include "asterisk/paths.h"
/* Use ast_log_safe in place of ast_log. */
#define ast_log ast_log_safe
static FILE *ref_log;
/*!

4
main/hashtab.c
View File

@@ -44,10 +44,6 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/hashtab.h"
#ifndef __AST_DEBUG_MALLOC
void *_ast_mem_backtrace_buffer[_AST_MEM_BACKTRACE_BUFLEN];
#endif
#if (defined(MALLOC_DEBUG) && !defined(STANDALONE))
static void _ast_hashtab_resize(struct ast_hashtab *tab, const char *file, int lineno, const char *func);
#define ast_hashtab_resize(a) _ast_hashtab_resize(a,__FILE__, __LINE__, __PRETTY_FUNCTION__)

27
main/logger.c
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@@ -102,6 +102,7 @@ static struct {
} logfiles = { 1 };
static char hostname[MAXHOSTNAMELEN];
AST_THREADSTORAGE_RAW(in_safe_log);
enum logtypes {
LOGTYPE_SYSLOG,
@@ -1719,6 +1720,32 @@ void ast_log(int level, const char *file, int line, const char *function, const
va_end(ap);
}
void ast_log_safe(int level, const char *file, int line, const char *function, const char *fmt, ...)
{
va_list ap;
void *recursed = ast_threadstorage_get_ptr(&in_safe_log);
ast_callid callid;
if (recursed) {
return;
}
if (ast_threadstorage_set_ptr(&in_safe_log, (void*)1)) {
/* We've failed to set the flag that protects against
* recursion, so bail. */
return;
}
callid = ast_read_threadstorage_callid();
va_start(ap, fmt);
ast_log_full(level, file, line, function, callid, fmt, ap);
va_end(ap);
/* Clear flag so the next allocation failure can be logged. */
ast_threadstorage_set_ptr(&in_safe_log, NULL);
}
void ast_log_callid(int level, const char *file, int line, const char *function, ast_callid callid, const char *fmt, ...)
{
va_list ap;

5
main/strings.c
View File

@@ -87,9 +87,6 @@ int __ast_str_helper(struct ast_str **buf, ssize_t max_len,
} else if (max_len == 0) { /* if unbounded, give more room for next time */
need += 16 + need / 4;
}
if (0) { /* debugging */
ast_verbose("extend from %d to %d\n", len, need);
}
if (
#if (defined(MALLOC_DEBUG) && !defined(STANDALONE))
_ast_str_make_space(buf, need, file, lineno, function)
@@ -97,7 +94,7 @@ int __ast_str_helper(struct ast_str **buf, ssize_t max_len,
ast_str_make_space(buf, need)
#endif
) {
ast_verbose("failed to extend from %d to %d\n", len, need);
ast_log_safe(LOG_VERBOSE, "failed to extend from %d to %d\n", len, need);
va_end(aq);
return AST_DYNSTR_BUILD_FAILED;
}