Re: [Tarantool-patches] [PATCH v4 2/4] backtrace: allow to specify destination buffer

[Serge Petrenko <sergepetrenko@tarantool.org>]

10.12.2020 19:18, Cyrill Gorcunov пишет:
> This will allow to reuse this routine in crash reports.
>
> Part-of #5261
>
> Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
> ---


LGTM.


>   src/lib/core/backtrace.cc | 12 ++++++------
>   src/lib/core/backtrace.h  |  3 +++
>   2 files changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/src/lib/core/backtrace.cc b/src/lib/core/backtrace.cc
> index 456ce9a4d..b4048089f 100644
> --- a/src/lib/core/backtrace.cc
> +++ b/src/lib/core/backtrace.cc
> @@ -131,7 +131,7 @@ get_proc_name(unw_cursor_t *unw_cur, unw_word_t *offset, bool skip_cache)
>   }
>   
>   char *
> -backtrace(void)
> +backtrace(char *start, size_t size)
>   {
>   	int frame_no = 0;
>   	unw_word_t sp = 0, old_sp = 0, ip, offset;
> @@ -139,10 +139,9 @@ backtrace(void)
>   	unw_getcontext(&unw_context);
>   	unw_cursor_t unw_cur;
>   	unw_init_local(&unw_cur, &unw_context);
> -	char *backtrace_buf = (char *)static_alloc(SMALL_STATIC_SIZE);
> -	char *p = backtrace_buf;
> -	char *end = p + SMALL_STATIC_SIZE - 1;
>   	int unw_status;
> +	char *p = start;
> +	char *end = start + size - 1;
>   	*p = '\0';
>   	while ((unw_status = unw_step(&unw_cur)) > 0) {
>   		const char *proc;
> @@ -174,7 +173,7 @@ backtrace(void)
>   		say_debug("unwinding error: %i", unw_status);
>   #endif
>   out:
> -	return backtrace_buf;
> +	return start;
>   }
>   
>   /*
> @@ -436,7 +435,8 @@ backtrace_foreach(backtrace_cb cb, coro_context *coro_ctx, void *cb_ctx)
>   void
>   print_backtrace(void)
>   {
> -	fdprintf(STDERR_FILENO, "%s", backtrace());
> +	char *start = (char *)static_alloc(SMALL_STATIC_SIZE);
> +	fdprintf(STDERR_FILENO, "%s", backtrace(start, SMALL_STATIC_SIZE));
>   }
>   #endif /* ENABLE_BACKTRACE */
>   
> diff --git a/src/lib/core/backtrace.h b/src/lib/core/backtrace.h
> index c119d5402..e0ae56be4 100644
> --- a/src/lib/core/backtrace.h
> +++ b/src/lib/core/backtrace.h
> @@ -40,6 +40,9 @@ extern "C" {
>   #ifdef ENABLE_BACKTRACE
>   #include <coro.h>
>   
> +char *
> +backtrace(char *start, size_t size);
> +
>   void print_backtrace(void);
>   
>   typedef int (backtrace_cb)(int frameno, void *frameret,

-- 
Serge Petrenko