diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt index 050d0a2f2..ba23d749a 100644 --- a/lib/CMakeLists.txt +++ b/lib/CMakeLists.txt @@ -153,6 +153,7 @@ set (LIB_HEADERS serialize.h service-management.h seqnum.h + stackdump.h str-format.h str-utils.h syslog-names.h @@ -249,6 +250,7 @@ set(LIB_SOURCES scratch-buffers.c serialize.c service-management.c + stackdump.c str-format.c str-utils.c syslog-names.c diff --git a/lib/Makefile.am b/lib/Makefile.am index 995360761..2e65e2562 100644 --- a/lib/Makefile.am +++ b/lib/Makefile.am @@ -172,6 +172,7 @@ pkginclude_HEADERS += \ lib/service-management.h \ lib/seqnum.h \ lib/signal-handler.h \ + lib/stackdump.h \ lib/str-format.h \ lib/str-utils.h \ lib/syslog-names.h \ @@ -264,6 +265,7 @@ lib_libsyslog_ng_la_SOURCES = \ lib/scratch-buffers.c \ lib/serialize.c \ lib/service-management.c \ + lib/stackdump.c \ lib/str-format.c \ lib/str-utils.c \ lib/syslog-names.c \ diff --git a/lib/gprocess.c b/lib/gprocess.c index 68cdd1a45..0e69c2c9e 100644 --- a/lib/gprocess.c +++ b/lib/gprocess.c @@ -27,6 +27,7 @@ #include "messages.h" #include "reloc.h" #include "console.h" +#include "stackdump.h" #include #include @@ -1306,6 +1307,14 @@ g_process_perform_supervise(void) exit(0); } + +static void +g_process_setup_fatal_signal_handler(void) +{ + stackdump_setup_signal(SIGSEGV); + stackdump_setup_signal(SIGABRT); +} + /** * g_process_start: * @@ -1409,6 +1418,8 @@ g_process_start(void) g_assert_not_reached(); } + g_process_setup_fatal_signal_handler(); + /* daemon process, we should return to the caller to perform work */ /* Only call setsid() for backgrounded processes. */ if (process_opts.mode != G_PM_FOREGROUND) diff --git a/lib/stackdump.c b/lib/stackdump.c new file mode 100644 index 000000000..2e7f32316 --- /dev/null +++ b/lib/stackdump.c @@ -0,0 +1,245 @@ +/* + * Copyright (c) 2024 Balázs Scheidler + * Copyright (c) 2024 Axoflow + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * As an additional exemption you are allowed to compile & link against the + * OpenSSL libraries as published by the OpenSSL project. See the file + * COPYING for details. + * + */ +#include "stackdump.h" +#include "console.h" + +#include +#include +#include +#include + +#ifdef __linux__ + +/* this is Linux only for now */ + +static void +_stackdump_print_stack(gpointer stack_pointer) +{ + guint8 *p = stack_pointer; + + for (gint i = 0; i < 16; i++) + { + gchar line[51] = {0}; + for (gint j = 0; j < 8; j++) + { + sprintf(&line[j*3], "%02x ", (guint) *(p+j)); + } + line[8*3] = ' '; + for (gint j = 8; j < 16; j++) + { + sprintf(&line[j*3 + 1], "%02x ", (guint) *(p+j)); + } + + console_printf("Stack %p: %s", p, line); + p += 16; + } +} + +/* should not do any allocation to allow this to work even if our heap is corrupted */ +static void +_stackdump_print_maps(void) +{ + int fd; + + console_printf("Maps file follows"); + fd = open("/proc/self/maps", O_RDONLY); + if (fd < 0) + { + console_printf("Error opening /proc/self/maps"); + return; + } + + gchar buf[1024]; + int rc; + gchar *p, *eol; + gint avail, end = 0; + + while (1) + { + avail = sizeof(buf) - end; + rc = read(fd, buf + end, avail); + + if (rc < 0) + break; + + end += rc; + + if (rc == 0) + break; + + p = buf; + while (*p && p < (buf + end)) + { + eol = memchr(p, '\n', buf + end - p); + if (eol) + { + *eol = 0; + console_printf("%s", p); + p = eol + 1; + } + else + { + end = end - (p - buf); + memmove(buf, p, end); + break; + } + } + } + if (end) + console_printf("%.*s", end, buf); + close(fd); +} + +static inline void +_stackdump_print_backtrace(void) +{ + void *bt[256]; + gint count; + + count = backtrace(bt, 256); + console_printf("Raw backtrace dump, count=%d", count); + for (gint i = 0; i < count; i++) + { + console_printf("[%d]: %p", i, bt[i]); + } + if (count) + { + gchar **symbols; + + console_printf("Symbol backtrace dump, count=%d", count); + symbols = backtrace_symbols(bt, count); + for (gint i = 0; i < count; i++) + { + console_printf("[%d]: %s", i, symbols[i]); + } + } +} + + +#ifdef __x86_64__ +/**************************************************************************** + * + * + * x86_64 support + * + * + ****************************************************************************/ + +void +_stackdump_print_registers(struct sigcontext *p) +{ + console_printf( + "Registers: " + "rax=%016lx rbx=%016lx rcx=%016lx rdx=%016lx rsi=%016lx rdi=%016lx " + "rbp=%016lx rsp=%016lx r8=%016lx r9=%016lx r10=%016lx r11=%016lx " + "r12=%016lx r13=%016lx r14=%016lx r15=%016lx rip=%016lx", + p->rax, p->rbx, p->rcx, p->rdx, p->rsi, p->rdi, p->rbp, p->rsp, p->r8, p->r9, p->r10, p->r11, p->r12, p->r13, p->r14, p->r15, p->rip); + _stackdump_print_stack((gpointer) p->rsp); +} + +#elif __x86__ +/**************************************************************************** + * + * + * i386 support + * + * + ****************************************************************************/ + +void +_stackdump_print_registers(struct sigcontext *p) +{ + console_printf( + "Registers: eax=%08lx ebx=%08lx ecx=%08lx edx=%08lx esi=%08lx edi=%08lx ebp=%08lx esp=%08lx eip=%08lx", + p->eax, p->ebx, p->ecx, p->edx, p->esi, p->edi, p->ebp, p->esp, p->eip); + _stackdump_print_stack((gpointer) p->esp); +} + +#else +/**************************************************************************** + * + * + * unsupported platform + * + * + ****************************************************************************/ + +static void +_stackdump_print_registers(struct sigcontext *p) +{ +} + +#endif + + +static inline void +_stackdump_log(struct sigcontext *p) +{ + /* the order is important here, even if it might be illogical. The + * backtrace function is the most fragile (as backtrace_symbols() may + * allocate memory). Let's log everything else first, and then we can + * produce the backtrace, which is potentially causing another crash. */ + + _stackdump_print_registers(p); + _stackdump_print_maps(); + _stackdump_print_backtrace(); +} + +static void +_fatal_signal_handler(int signo, siginfo_t *info, void *uc) +{ + struct ucontext_t *ucontext = (struct ucontext_t *) uc; + struct sigcontext *p = (struct sigcontext *) &ucontext->uc_mcontext; + struct sigaction act; + + memset(&act, 0, sizeof(act)); + act.sa_handler = SIG_DFL; + sigaction(signo, &act, NULL); + + console_printf("Fatal signal received, stackdump follows, signal=%d", signo); + _stackdump_log(p); + /* let's get a stacktrace as well */ + kill(getpid(), signo); +} + +void +stackdump_setup_signal(gint signal_number) +{ + struct sigaction act; + + memset(&act, 0, sizeof(act)); + act.sa_flags = SA_SIGINFO; + act.sa_sigaction = _fatal_signal_handler; + + sigaction(signal_number, &act, NULL); +} + +#else + +void +stackdump_setup_signal(gint signal_number) +{ +} + +#endif diff --git a/lib/stackdump.h b/lib/stackdump.h new file mode 100644 index 000000000..7942f651c --- /dev/null +++ b/lib/stackdump.h @@ -0,0 +1,31 @@ +/* + * Copyright (c) 2024 Balázs Scheidler + * Copyright (c) 2024 Axoflow + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * As an additional exemption you are allowed to compile & link against the + * OpenSSL libraries as published by the OpenSSL project. See the file + * COPYING for details. + * + */ +#ifndef STACKDUMP_H_INCLUDED +#define STACKDUMP_H_INCLUDED + +#include "syslog-ng.h" + +void stackdump_setup_signal(gint signal_number); + +#endif