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Diffstat (limited to 'tests/backtrace-child.c')
| -rw-r--r-- | tests/backtrace-child.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/tests/backtrace-child.c b/tests/backtrace-child.c new file mode 100644 index 00000000..2bc0eded --- /dev/null +++ b/tests/backtrace-child.c @@ -0,0 +1,221 @@ +/* Test child for parent backtrace test. + Copyright (C) 2013 Red Hat, Inc. + This file is part of elfutils. + + This file is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + elfutils is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +/* Command line syntax: ./backtrace-child [--ptraceme|--gencore] + --ptraceme will call ptrace (PTRACE_TRACEME) in the two threads. + --gencore will call abort () at its end. + Main thread will signal SIGUSR2. Other thread will signal SIGUSR1. + On x86_64 only: + PC will get changed to function 'jmp' by backtrace.c function + prepare_thread. Then SIGUSR2 will be signalled to backtrace-child + which will invoke function sigusr2. + This is all done so that signal interrupts execution of the very first + instruction of a function. Properly handled unwind should not slip into + the previous unrelated function. + The tested functionality is arch-independent but the code reproducing it + has to be arch-specific. + On non-x86_64: + sigusr2 gets called by normal function call from function stdarg. + On any arch then sigusr2 calls raise (SIGUSR1) for --ptraceme. + abort () is called otherwise, expected for --gencore core dump. + + Expected x86_64 output: + TID 10276: + # 0 0x7f7ab61e9e6b raise + # 1 0x7f7ab661af47 - 1 main + # 2 0x7f7ab5e3bb45 - 1 __libc_start_main + # 3 0x7f7ab661aa09 - 1 _start + TID 10278: + # 0 0x7f7ab61e9e6b raise + # 1 0x7f7ab661ab3c - 1 sigusr2 + # 2 0x7f7ab5e4fa60 __restore_rt + # 3 0x7f7ab661ab47 jmp + # 4 0x7f7ab661ac92 - 1 stdarg + # 5 0x7f7ab661acba - 1 backtracegen + # 6 0x7f7ab661acd1 - 1 start + # 7 0x7f7ab61e2c53 - 1 start_thread + # 8 0x7f7ab5f0fdbd - 1 __clone + + Expected non-x86_64 (i386) output; __kernel_vsyscall are skipped if found: + TID 10408: + # 0 0xf779f430 __kernel_vsyscall + # 1 0xf7771466 - 1 raise + # 2 0xf77c1d07 - 1 main + # 3 0xf75bd963 - 1 __libc_start_main + # 4 0xf77c1761 - 1 _start + TID 10412: + # 0 0xf779f430 __kernel_vsyscall + # 1 0xf7771466 - 1 raise + # 2 0xf77c18f4 - 1 sigusr2 + # 3 0xf77c1a10 - 1 stdarg + # 4 0xf77c1a2c - 1 backtracegen + # 5 0xf77c1a48 - 1 start + # 6 0xf77699da - 1 start_thread + # 7 0xf769bbfe - 1 __clone + */ + +#include <config.h> +#include <assert.h> +#include <stdlib.h> +#include <signal.h> +#include <errno.h> +#include <sys/ptrace.h> +#include <string.h> +#include <pthread.h> +#include <stdio.h> +#include <unistd.h> + +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5) +#define NOINLINE_NOCLONE __attribute__ ((noinline, noclone)) +#else +#define NOINLINE_NOCLONE __attribute__ ((noinline)) +#endif + +#define NORETURN __attribute__ ((noreturn)) +#define UNUSED __attribute__ ((unused)) +#define USED __attribute__ ((used)) + +static int ptraceme, gencore; + +/* Execution will arrive here from jmp by an artificial ptrace-spawn signal. */ + +static void +sigusr2 (int signo) +{ + assert (signo == SIGUSR2); + if (! gencore) + { + raise (SIGUSR1); + /* It should not be reached. */ + abort (); + } + /* Here we dump the core for --gencore. */ + raise (SIGABRT); +} + +static NOINLINE_NOCLONE void +dummy1 (void) +{ + asm volatile (""); +} + +#ifdef __x86_64__ +static NOINLINE_NOCLONE USED void +jmp (void) +{ + /* Not reached, signal will get ptrace-spawn to jump into sigusr2. */ + abort (); +} +#endif + +static NOINLINE_NOCLONE void +dummy2 (void) +{ + asm volatile (""); +} + +static NOINLINE_NOCLONE NORETURN void +stdarg (int f UNUSED, ...) +{ + sighandler_t sigusr2_orig = signal (SIGUSR2, sigusr2); + assert (sigusr2_orig == SIG_DFL); + errno = 0; + if (ptraceme) + { + long l = ptrace (PTRACE_TRACEME, 0, NULL, NULL); + assert_perror (errno); + assert (l == 0); + } +#ifdef __x86_64__ + if (! gencore) + { + /* Execution will get PC patched into function jmp. */ + raise (SIGUSR1); + } +#endif + sigusr2 (SIGUSR2); + /* Not reached. */ + abort (); +} + +static NOINLINE_NOCLONE void +dummy3 (void) +{ + asm volatile (""); +} + +static NOINLINE_NOCLONE void +backtracegen (void) +{ + stdarg (1); + /* Here should be no instruction after the stdarg call as it is noreturn + function. It must be stdarg so that it is a call and not jump (jump as + a tail-call). */ +} + +static NOINLINE_NOCLONE void +dummy4 (void) +{ + asm volatile (""); +} + +static void * +start (void *arg UNUSED) +{ + backtracegen (); + /* Not reached. */ + abort (); +} + +int +main (int argc UNUSED, char **argv) +{ + setbuf (stdout, NULL); + assert (*argv++); + ptraceme = (*argv && strcmp (*argv, "--ptraceme") == 0); + argv += ptraceme; + gencore = (*argv && strcmp (*argv, "--gencore") == 0); + argv += gencore; + assert (!*argv); + /* These dummy* functions are there so that each of their surrounding + functions has some unrelated code around. The purpose of some of the + tests is verify unwinding the very first / after the very last instruction + does not inappropriately slip into the unrelated code around. */ + dummy1 (); + dummy2 (); + dummy3 (); + dummy4 (); + if (gencore) + printf ("%ld\n", (long) getpid ()); + pthread_t thread; + int i = pthread_create (&thread, NULL, start, NULL); + // pthread_* functions do not set errno. + assert (i == 0); + if (ptraceme) + { + errno = 0; + long l = ptrace (PTRACE_TRACEME, 0, NULL, NULL); + assert_perror (errno); + assert (l == 0); + } + if (gencore) + pthread_join (thread, NULL); + else + raise (SIGUSR2); + /* Not reached. */ + abort (); +} |