From b1d6f6efe425c93ba5d692f6c6be53d3ef52606d Mon Sep 17 00:00:00 2001 From: Gregory LEOCADIE Date: Thu, 5 Jan 2023 16:13:29 +0100 Subject: Adjust backtrace2 signature --- doc/unw_backtrace.man | 14 ++++++++++---- doc/unw_backtrace.tex | 6 ++++-- include/libunwind-common.h.in | 2 +- src/mi/backtrace.c | 6 +++--- tests/Gtest-trace.c | 2 +- 5 files changed, 19 insertions(+), 11 deletions(-) diff --git a/doc/unw_backtrace.man b/doc/unw_backtrace.man index 91a693ab..e1a4a9df 100644 --- a/doc/unw_backtrace.man +++ b/doc/unw_backtrace.man @@ -1,7 +1,7 @@ .\" *********************************** start of \input{common.tex} .\" *********************************** end of \input{common.tex} '\" t -.\" Manual page created with latex2man on Thu Dec 8 12:01:30 2022 +.\" Manual page created with latex2man on Thu Jan 5 15:33:00 2023 .\" NOTE: This file is generated, DO NOT EDIT. .de Vb .ft CW @@ -12,7 +12,7 @@ .fi .. -.TH "UNW\\_BACKTRACE" "3" "08 December 2022" "Programming Library " "Programming Library " +.TH "UNW\\_BACKTRACE" "3" "05 January 2023" "Programming Library " "Programming Library " .SH NAME unw_backtrace \-\- return backtrace for the calling program @@ -30,7 +30,8 @@ int size); int unw_backtrace2(void **buffer, int size, -unw_context_t *ctxt); +unw_context_t *ctxt, +int flag); .br .PP #include @@ -68,11 +69,16 @@ is linked against libunwind, it may end up calling unw_backtrace(). .PP +In case you want to obtain the backtrace from a specific unw_context_t, +you can call unw_backtrace2 +with that context passing 0 +for flag. If the unw_context_t is known to be a signal frame (i.e., from the third argument in a sigaction handler on linux), unw_backtrace2 can be used to collect -only the frames before the signal frame. +only the frames before the signal frame passing the UNW_INIT_SIGNAL_FRAME +flag. .PP .SH RETURN VALUE diff --git a/doc/unw_backtrace.tex b/doc/unw_backtrace.tex index 205aaea4..3e5152b6 100644 --- a/doc/unw_backtrace.tex +++ b/doc/unw_backtrace.tex @@ -13,7 +13,7 @@ \File{\#include $<$libunwind.h$>$}\\ \Type{int} \Func{unw\_backtrace}(\Type{void~**}\Var{buffer}, \Type{int}~\Var{size});\\ -\Type{int} \Func{unw\_backtrace2}(\Type{void~**}\Var{buffer}, \Type{int}~\Var{size}, \Type{unw_context_t~*}\Var{ctxt});\\ +\Type{int} \Func{unw\_backtrace2}(\Type{void~**}\Var{buffer}, \Type{int}~\Var{size}, \Type{unw_context_t~*}\Var{ctxt}, \Type{int}~\Var{flag});\\ \File{\#include $<$execinfo.h$>$}\\ @@ -33,9 +33,11 @@ aliases \Func{backtrace}() to \Func{unw\_backtrace}(), so when a program calling \Func{backtrace}() is linked against \Prog{libunwind}, it may end up calling \Func{unw\_backtrace}(). +In case you want to obtain the backtrace from a specific \Type{unw\_context\_t}, +you can call \Func{unw\_backtrace2} with that context passing \Const{0} for flag. If the \Type{unw\_context_t} is known to be a signal frame (i.e., from the third argument in a sigaction handler on linux), \Func{unw\_backtrace2} can be used to collect -only the frames before the signal frame. +only the frames before the signal frame passing the \Const{UNW\_INIT\_SIGNAL\_FRAME} flag. \section{Return Value} diff --git a/include/libunwind-common.h.in b/include/libunwind-common.h.in index 3f04a1c4..7360a028 100644 --- a/include/libunwind-common.h.in +++ b/include/libunwind-common.h.in @@ -316,6 +316,6 @@ extern int unw_get_proc_name_by_ip (unw_addr_space_t, unw_word_t, char *, size_t, unw_word_t *, void *); extern const char *unw_strerror (int); extern int unw_backtrace (void **, int); -extern int unw_backtrace2 (void **, int, unw_context_t*); +extern int unw_backtrace2 (void **, int, unw_context_t*, int); extern unw_addr_space_t unw_local_addr_space; diff --git a/src/mi/backtrace.c b/src/mi/backtrace.c index 8fea3444..e532b79d 100644 --- a/src/mi/backtrace.c +++ b/src/mi/backtrace.c @@ -77,7 +77,7 @@ unw_backtrace (void **buffer, int size) } int -unw_backtrace2 (void **buffer, int size, unw_context_t* uc2) +unw_backtrace2 (void **buffer, int size, unw_context_t* uc2, int flag) { if (size == 0) return 0; @@ -89,7 +89,7 @@ unw_backtrace2 (void **buffer, int size, unw_context_t* uc2) // need to copy, because the context will be modified by tdep_trace unw_context_t uc = *(unw_context_t*)uc2; - if (unlikely (unw_init_local2 (&cursor, &uc, UNW_INIT_SIGNAL_FRAME) < 0)) + if (unlikely (unw_init_local2 (&cursor, &uc, flag) < 0)) return 0; // get the first ip from the context @@ -110,7 +110,7 @@ unw_backtrace2 (void **buffer, int size, unw_context_t* uc2) // and add 1 to it (the one we retrieved above) if (unlikely (tdep_trace (&cursor, buffer, &n) < 0)) { - return slow_backtrace (buffer, remaining_size, &uc, UNW_INIT_SIGNAL_FRAME) + 1; + return slow_backtrace (buffer, remaining_size, &uc, flag) + 1; } return n + 1; diff --git a/tests/Gtest-trace.c b/tests/Gtest-trace.c index e0a5d64d..5f22f1fb 100644 --- a/tests/Gtest-trace.c +++ b/tests/Gtest-trace.c @@ -174,7 +174,7 @@ do_backtrace_with_context(void *context) if (verbose) printf ("\n\tvia unw_backtrace2():\n"); - m = unw_backtrace2 (addresses[1], 128, (unw_context_t*)context); + m = unw_backtrace2 (addresses[1], 128, (unw_context_t*)context, UNW_INIT_SIGNAL_FRAME); if (verbose) for (i = 0; i < m; ++i) -- cgit v1.2.1