strace/unwind.c
Dmitry V. Levin 0b03de74bc build: prepare for -Wimplicit-fallthrough=5
* gcc_compat.h (ATTRIBUTE_FALLTHROUGH): New macro.
* block.c (block_ioctl): Use it instead of "fall through" comment.
* btrfs.c (btrfs_ioctl): Likewise.
* loop.c (loop_ioctl): Likewise.
* mtd.c (mtd_ioctl): Likewise.
* rtc.c (rtc_ioctl): Likewise.
* v4l2.c (v4l2_ioctl): Likewise.
* dm.c (dm_decode_values): Likewise.
* process.c (SYS_FUNC(ptrace)): Likewise.
* quota.c (decode_cmd_data): Likewise.
* ucopy.c (umovestr): Likewise.
* unwind.c (unwind_print_stacktrace, unwind_capture_stacktrace)):
Likewise.
* term.c (term_ioctl): Add ATTRIBUTE_FALLTHROUGH.
* ioctl.c (ioctl_decode) [ALPHA || POWERPC]: Likewise.
* m4/st_warn_cflags.m4 (gl_WARN_ADD): Add -Wimplicit-fallthrough=5.
* tests/ioctl_v4l2.c (init_v4l2_format): Reorganize the switch statement
without implicit fallthrough.
2018-03-06 23:52:08 +00:00

441 lines
10 KiB
C

/*
* Copyright (c) 2013 Luca Clementi <luca.clementi@gmail.com>
* Copyright (c) 2013-2018 The strace developers.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "defs.h"
#include "mmap_cache.h"
#include <libunwind-ptrace.h>
#ifdef USE_DEMANGLE
# if defined HAVE_DEMANGLE_H
# include <demangle.h>
# elif defined HAVE_LIBIBERTY_DEMANGLE_H
# include <libiberty/demangle.h>
# endif
#endif
/*
* Type used in stacktrace walker
*/
typedef void (*call_action_fn)(void *data,
const char *binary_filename,
const char *symbol_name,
unw_word_t function_offset,
unsigned long true_offset);
typedef void (*error_action_fn)(void *data,
const char *error,
unsigned long true_offset);
/*
* Type used in stacktrace capturing
*/
struct call_t {
struct call_t *next;
char *output_line;
};
struct queue_t {
struct call_t *tail;
struct call_t *head;
};
static void queue_print(struct queue_t *queue);
static unw_addr_space_t libunwind_as;
static const char asprintf_error_str[] = "???";
void
unwind_init(void)
{
libunwind_as = unw_create_addr_space(&_UPT_accessors, 0);
if (!libunwind_as)
error_msg_and_die("failed to create address space for stack tracing");
unw_set_caching_policy(libunwind_as, UNW_CACHE_GLOBAL);
mmap_cache_enable();
}
void
unwind_tcb_init(struct tcb *tcp)
{
if (tcp->libunwind_ui)
return;
tcp->libunwind_ui = _UPT_create(tcp->pid);
if (!tcp->libunwind_ui)
perror_msg_and_die("_UPT_create");
tcp->queue = xmalloc(sizeof(*tcp->queue));
tcp->queue->head = NULL;
tcp->queue->tail = NULL;
}
void
unwind_tcb_fin(struct tcb *tcp)
{
queue_print(tcp->queue);
free(tcp->queue);
tcp->queue = NULL;
_UPT_destroy(tcp->libunwind_ui);
tcp->libunwind_ui = NULL;
}
static void
get_symbol_name(unw_cursor_t *cursor, char **name,
size_t *size, unw_word_t *offset)
{
for (;;) {
int rc = unw_get_proc_name(cursor, *name, *size, offset);
if (rc == 0)
break;
if (rc != -UNW_ENOMEM) {
**name = '\0';
*offset = 0;
break;
}
*name = xgrowarray(*name, size, 1);
}
}
static int
print_stack_frame(struct tcb *tcp,
call_action_fn call_action,
error_action_fn error_action,
void *data,
unw_cursor_t *cursor,
char **symbol_name,
size_t *symbol_name_size)
{
unw_word_t ip;
struct mmap_cache_t *cur_mmap_cache;
if (unw_get_reg(cursor, UNW_REG_IP, &ip) < 0) {
perror_msg("Can't walk the stack of process %d", tcp->pid);
return -1;
}
cur_mmap_cache = mmap_cache_search(tcp, ip);
if (cur_mmap_cache
/* ignore mappings that have no PROT_EXEC bit set */
&& (cur_mmap_cache->protections & MMAP_CACHE_PROT_EXECUTABLE)) {
unsigned long true_offset;
unw_word_t function_offset;
get_symbol_name(cursor, symbol_name, symbol_name_size,
&function_offset);
true_offset = ip - cur_mmap_cache->start_addr +
cur_mmap_cache->mmap_offset;
#ifdef USE_DEMANGLE
char *demangled_name =
cplus_demangle(*symbol_name,
DMGL_AUTO | DMGL_PARAMS);
#endif
call_action(data,
cur_mmap_cache->binary_filename,
#ifdef USE_DEMANGLE
demangled_name ? demangled_name :
#endif
*symbol_name,
function_offset,
true_offset);
#ifdef USE_DEMANGLE
free(demangled_name);
#endif
return 0;
}
/*
* there is a bug in libunwind >= 1.0
* after a set_tid_address syscall
* unw_get_reg returns IP == 0
*/
if (ip)
error_action(data, "unexpected_backtracing_error", ip);
return -1;
}
/*
* walking the stack
*/
static void
stacktrace_walk(struct tcb *tcp,
call_action_fn call_action,
error_action_fn error_action,
void *data)
{
char *symbol_name;
size_t symbol_name_size = 40;
unw_cursor_t cursor;
int stack_depth;
if (!tcp->mmap_cache)
error_msg_and_die("bug: mmap_cache is NULL");
if (tcp->mmap_cache_size == 0)
error_msg_and_die("bug: mmap_cache is empty");
symbol_name = xmalloc(symbol_name_size);
if (unw_init_remote(&cursor, libunwind_as, tcp->libunwind_ui) < 0)
perror_msg_and_die("Can't initiate libunwind");
for (stack_depth = 0; stack_depth < 256; ++stack_depth) {
if (print_stack_frame(tcp, call_action, error_action, data,
&cursor, &symbol_name, &symbol_name_size) < 0)
break;
if (unw_step(&cursor) <= 0)
break;
}
if (stack_depth >= 256)
error_action(data, "too many stack frames", 0);
free(symbol_name);
}
/*
* printing an entry in stack to stream or buffer
*/
/*
* we want to keep the format used by backtrace_symbols from the glibc
*
* ./a.out() [0x40063d]
* ./a.out() [0x4006bb]
* ./a.out() [0x4006c6]
* /lib64/libc.so.6(__libc_start_main+0xed) [0x7fa2f8a5976d]
* ./a.out() [0x400569]
*/
#define STACK_ENTRY_SYMBOL_FMT \
" > %s(%s+0x%lx) [0x%lx]\n", \
binary_filename, \
symbol_name, \
(unsigned long) function_offset, \
true_offset
#define STACK_ENTRY_NOSYMBOL_FMT \
" > %s() [0x%lx]\n", \
binary_filename, true_offset
#define STACK_ENTRY_BUG_FMT \
" > BUG IN %s\n"
#define STACK_ENTRY_ERROR_WITH_OFFSET_FMT \
" > %s [0x%lx]\n", error, true_offset
#define STACK_ENTRY_ERROR_FMT \
" > %s\n", error
static void
print_call_cb(void *dummy,
const char *binary_filename,
const char *symbol_name,
unw_word_t function_offset,
unsigned long true_offset)
{
if (symbol_name && (symbol_name[0] != '\0'))
tprintf(STACK_ENTRY_SYMBOL_FMT);
else if (binary_filename)
tprintf(STACK_ENTRY_NOSYMBOL_FMT);
else
tprintf(STACK_ENTRY_BUG_FMT, __func__);
line_ended();
}
static void
print_error_cb(void *dummy,
const char *error,
unsigned long true_offset)
{
if (true_offset)
tprintf(STACK_ENTRY_ERROR_WITH_OFFSET_FMT);
else
tprintf(STACK_ENTRY_ERROR_FMT);
line_ended();
}
static char *
sprint_call_or_error(const char *binary_filename,
const char *symbol_name,
unw_word_t function_offset,
unsigned long true_offset,
const char *error)
{
char *output_line = NULL;
int n;
if (symbol_name)
n = asprintf(&output_line, STACK_ENTRY_SYMBOL_FMT);
else if (binary_filename)
n = asprintf(&output_line, STACK_ENTRY_NOSYMBOL_FMT);
else if (error)
n = true_offset
? asprintf(&output_line, STACK_ENTRY_ERROR_WITH_OFFSET_FMT)
: asprintf(&output_line, STACK_ENTRY_ERROR_FMT);
else
n = asprintf(&output_line, STACK_ENTRY_BUG_FMT, __func__);
if (n < 0) {
perror_func_msg("asprintf");
output_line = (char *) asprintf_error_str;
}
return output_line;
}
/*
* queue manipulators
*/
static void
queue_put(struct queue_t *queue,
const char *binary_filename,
const char *symbol_name,
unw_word_t function_offset,
unsigned long true_offset,
const char *error)
{
struct call_t *call;
call = xmalloc(sizeof(*call));
call->output_line = sprint_call_or_error(binary_filename,
symbol_name,
function_offset,
true_offset,
error);
call->next = NULL;
if (!queue->head) {
queue->head = call;
queue->tail = call;
} else {
queue->tail->next = call;
queue->tail = call;
}
}
static void
queue_put_call(void *queue,
const char *binary_filename,
const char *symbol_name,
unw_word_t function_offset,
unsigned long true_offset)
{
queue_put(queue,
binary_filename,
symbol_name,
function_offset,
true_offset,
NULL);
}
static void
queue_put_error(void *queue,
const char *error,
unsigned long ip)
{
queue_put(queue, NULL, NULL, 0, ip, error);
}
static void
queue_print(struct queue_t *queue)
{
struct call_t *call, *tmp;
queue->tail = NULL;
call = queue->head;
queue->head = NULL;
while (call) {
tmp = call;
call = call->next;
tprints(tmp->output_line);
line_ended();
if (tmp->output_line != asprintf_error_str)
free(tmp->output_line);
tmp->output_line = NULL;
tmp->next = NULL;
free(tmp);
}
}
/*
* printing stack
*/
void
unwind_print_stacktrace(struct tcb *tcp)
{
#if SUPPORTED_PERSONALITIES > 1
if (tcp->currpers != DEFAULT_PERSONALITY) {
/* disable stack trace */
return;
}
#endif
if (tcp->queue->head) {
debug_func_msg("head: tcp=%p, queue=%p", tcp, tcp->queue->head);
queue_print(tcp->queue);
} else switch (mmap_cache_rebuild_if_invalid(tcp, __func__)) {
case MMAP_CACHE_REBUILD_RENEWED:
unw_flush_cache(libunwind_as, 0, 0);
ATTRIBUTE_FALLTHROUGH;
case MMAP_CACHE_REBUILD_READY:
debug_func_msg("walk: tcp=%p, queue=%p", tcp, tcp->queue->head);
stacktrace_walk(tcp, print_call_cb, print_error_cb, NULL);
break;
default:
/* Do nothing */
;
}
}
/*
* capturing stack
*/
void
unwind_capture_stacktrace(struct tcb *tcp)
{
#if SUPPORTED_PERSONALITIES > 1
if (tcp->currpers != DEFAULT_PERSONALITY) {
/* disable stack trace */
return;
}
#endif
if (tcp->queue->head)
error_msg_and_die("bug: unprinted entries in queue");
switch (mmap_cache_rebuild_if_invalid(tcp, __func__)) {
case MMAP_CACHE_REBUILD_RENEWED:
unw_flush_cache(libunwind_as, 0, 0);
ATTRIBUTE_FALLTHROUGH;
case MMAP_CACHE_REBUILD_READY:
stacktrace_walk(tcp, queue_put_call, queue_put_error,
tcp->queue);
debug_func_msg("tcp=%p, queue=%p", tcp, tcp->queue->head);
break;
default:
/* Do nothing */
;
}
}