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backtrace.c (backtrace_full): When testing whether we can allocate memory... 

* backtrace.c (backtrace_full): When testing whether we can
	allocate memory, call mmap directly, and munmap the memory.

Fixes https://github.com/ianlancetaylor/libbacktrace/issues/13 .

From-SVN: r259434
This commit is contained in:
Ian Lance Taylor 2018-04-17 13:59:38 +00:00 committed by Ian Lance Taylor
parent 50ffe7adc0
commit 83a658ca0b
2 changed files with 38 additions and 11 deletions
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5
libbacktrace/ChangeLog
View File

@ -1,3 +1,8 @@
2018-04-17 Ian Lance Taylor <iant@golang.org>
* backtrace.c (backtrace_full): When testing whether we can
allocate memory, call mmap directly, and munmap the memory.
2018-04-04 Jakub Jelinek <jakub@redhat.com>
PR other/85161

44
libbacktrace/backtrace.c
View File

@ -32,12 +32,26 @@ POSSIBILITY OF SUCH DAMAGE. */
#include "config.h"
#include <unistd.h>
#include <sys/types.h>
#if !BACKTRACE_USES_MALLOC
#include <sys/mman.h>
#endif
#include "unwind.h"
#include "backtrace.h"
#include "backtrace-supported.h"
#include "internal.h"
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
#ifndef MAP_FAILED
#define MAP_FAILED ((void *)-1)
#endif
/* The main backtrace_full routine. */
/* Data passed through _Unwind_Backtrace. */
@ -104,7 +118,6 @@ backtrace_full (struct backtrace_state *state, int skip,
backtrace_error_callback error_callback, void *data)
{
struct backtrace_data bdata;
void *p;
bdata.skip = skip + 1;
bdata.state = state;
@ -113,16 +126,25 @@ backtrace_full (struct backtrace_state *state, int skip,
bdata.data = data;
bdata.ret = 0;
/* If we can't allocate any memory at all, don't try to produce
file/line information. */
p = backtrace_alloc (state, 4096, NULL, NULL);
if (p == NULL)
bdata.can_alloc = 0;
else
{
backtrace_free (state, p, 4096, NULL, NULL);
bdata.can_alloc = 1;
}
#if !BACKTRACE_USES_MALLOC
{
size_t pagesize;
void *page;
/* If we can't allocate any memory at all, don't try to produce
file/line information. */
pagesize = getpagesize ();
page = mmap (NULL, pagesize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (page == MAP_FAILED)
bdata.can_alloc = 0;
else
{
munmap (page, pagesize);
bdata.can_alloc = 1;
}
}
#endif
_Unwind_Backtrace (unwind, &bdata);
return bdata.ret;