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-rw-r--r--toolkit/xre/nsSigHandlers.cpp450
1 files changed, 450 insertions, 0 deletions
diff --git a/toolkit/xre/nsSigHandlers.cpp b/toolkit/xre/nsSigHandlers.cpp
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+++ b/toolkit/xre/nsSigHandlers.cpp
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This module is supposed to abstract signal handling away from the other
+ * platforms that do not support it.
+ */
+
+#include "nsSigHandlers.h"
+
+#ifdef XP_UNIX
+
+# include <signal.h>
+# include <stdio.h>
+# include <string.h>
+# include "prthread.h"
+# include "prenv.h"
+# include "nsDebug.h"
+# include "nsString.h"
+# include "nsXULAppAPI.h"
+
+# if defined(LINUX)
+# include <sys/time.h>
+# include <sys/resource.h>
+# include <unistd.h>
+# include <stdlib.h> // atoi
+# include <sys/prctl.h>
+# ifndef ANDROID // no Android impl
+# include <ucontext.h>
+# endif
+# endif
+
+# if defined(SOLARIS)
+# include <sys/resource.h>
+# include <ucontext.h>
+# endif
+
+# ifdef MOZ_WIDGET_GTK
+# include <dlfcn.h>
+# endif
+
+// Note: some tests manipulate this value.
+unsigned int _gdb_sleep_duration = 300;
+
+# if defined(LINUX) && !defined(ANDROID) && defined(DEBUG) && \
+ (defined(__i386) || defined(__x86_64) || defined(PPC))
+# define CRAWL_STACK_ON_SIGSEGV
+# endif
+
+# ifndef PR_SET_PTRACER
+# define PR_SET_PTRACER 0x59616d61
+# endif
+# ifndef PR_SET_PTRACER_ANY
+# define PR_SET_PTRACER_ANY ((unsigned long)-1)
+# endif
+
+# if defined(CRAWL_STACK_ON_SIGSEGV)
+
+# include <unistd.h>
+# include "nsISupportsUtils.h"
+# include "mozilla/Attributes.h"
+# include "mozilla/StackWalk.h"
+
+static const char* gProgname = "huh?";
+
+// NB: keep me up to date with the same variable in
+// ipc/chromium/chrome/common/ipc_channel_posix.cc
+static const int kClientChannelFd = 3;
+
+extern "C" {
+
+static void PrintStackFrame(uint32_t aFrameNumber, void* aPC, void* aSP,
+ void* aClosure) {
+ char buf[1024];
+ MozCodeAddressDetails details;
+
+ MozDescribeCodeAddress(aPC, &details);
+ MozFormatCodeAddressDetails(buf, sizeof(buf), aFrameNumber, aPC, &details);
+ fprintf(stdout, "%s\n", buf);
+ fflush(stdout);
+}
+}
+
+void common_crap_handler(int signum, const void* aFirstFramePC) {
+ printf("\nProgram %s (pid = %d) received signal %d.\n", gProgname, getpid(),
+ signum);
+
+ printf("Stack:\n");
+ MozStackWalk(PrintStackFrame, aFirstFramePC, /* maxFrames */ 0, nullptr);
+
+ printf("Sleeping for %d seconds.\n", _gdb_sleep_duration);
+ printf("Type 'gdb %s %d' to attach your debugger to this thread.\n",
+ gProgname, getpid());
+
+ // Allow us to be ptraced by gdb on Linux with Yama restrictions enabled.
+ prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY);
+
+ sleep(_gdb_sleep_duration);
+
+ printf("Done sleeping...\n");
+
+ _exit(signum);
+}
+
+MOZ_NEVER_INLINE void ah_crap_handler(int signum) {
+ common_crap_handler(signum, CallerPC());
+}
+
+MOZ_NEVER_INLINE void child_ah_crap_handler(int signum) {
+ if (!getenv("MOZ_DONT_UNBLOCK_PARENT_ON_CHILD_CRASH"))
+ close(kClientChannelFd);
+ common_crap_handler(signum, CallerPC());
+}
+
+# endif // CRAWL_STACK_ON_SIGSEGV
+
+# ifdef MOZ_WIDGET_GTK
+// Need this include for version test below.
+# include <glib.h>
+# endif
+
+# if defined(MOZ_WIDGET_GTK)
+
+# if GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION < 50
+// These types are only available in glib 2.50+
+typedef enum {
+ G_LOG_WRITER_HANDLED = 1,
+ G_LOG_WRITER_UNHANDLED = 0,
+} GLogWriterOutput;
+typedef struct _GLogField GLogField;
+struct _GLogField {
+ const gchar* key;
+ gconstpointer value;
+ gssize length;
+};
+typedef GLogWriterOutput (*GLogWriterFunc)(GLogLevelFlags log_level,
+ const GLogField* fields,
+ gsize n_fields, gpointer user_data);
+# endif
+
+static GLogFunc orig_log_func = nullptr;
+
+extern "C" {
+static void glib_log_func(const gchar* log_domain, GLogLevelFlags log_level,
+ const gchar* message, gpointer user_data);
+static GLogWriterOutput glib_log_writer_func(GLogLevelFlags, const GLogField*,
+ gsize, gpointer);
+}
+
+// GDK sometimes avoids calling exit handlers, but we still want to know when we
+// crash, see https://gitlab.gnome.org/GNOME/gtk/-/issues/4514 and bug 1743144.
+static bool IsCrashyGtkMessage(const nsACString& aMessage) {
+ if (aMessage.EqualsLiteral("Lost connection to Wayland compositor.")) {
+ // https://gitlab.gnome.org/GNOME/gtk/-/blob/gtk-3-24/gdk/wayland/gdkeventsource.c#L210
+ return true;
+ }
+ if (StringBeginsWith(aMessage, "Error flushing display: "_ns)) {
+ // https://gitlab.gnome.org/GNOME/gtk/-/blob/gtk-3-24/gdk/wayland/gdkeventsource.c#L68
+ return true;
+ }
+ if (StringBeginsWith(aMessage, "Error reading events from display: "_ns)) {
+ // https://gitlab.gnome.org/GNOME/gtk/-/blob/gtk-3-24/gdk/wayland/gdkeventsource.c#L97
+ return true;
+ }
+ if (StringBeginsWith(aMessage, "Error "_ns) &&
+ StringEndsWith(aMessage, " dispatching to Wayland display."_ns)) {
+ // https://gitlab.gnome.org/GNOME/gtk/-/blob/gtk-3-24/gdk/wayland/gdkeventsource.c#L205
+ return true;
+ }
+ return false;
+}
+
+static void HandleGLibMessage(GLogLevelFlags aLogLevel,
+ const nsDependentCString& aMessage) {
+ if (MOZ_UNLIKELY(IsCrashyGtkMessage(aMessage))) {
+ MOZ_CRASH_UNSAFE(strdup(aMessage.get()));
+ }
+
+ if (aLogLevel &
+ (G_LOG_LEVEL_ERROR | G_LOG_FLAG_FATAL | G_LOG_FLAG_RECURSION)) {
+ NS_DebugBreak(NS_DEBUG_ASSERTION, aMessage.get(), "glib assertion",
+ __FILE__, __LINE__);
+ } else if (aLogLevel & (G_LOG_LEVEL_CRITICAL | G_LOG_LEVEL_WARNING)) {
+ NS_DebugBreak(NS_DEBUG_WARNING, aMessage.get(), "glib warning", __FILE__,
+ __LINE__);
+ }
+}
+
+/* static */ void glib_log_func(const gchar* log_domain,
+ GLogLevelFlags log_level, const gchar* message,
+ gpointer user_data) {
+ HandleGLibMessage(log_level, nsDependentCString(message));
+ orig_log_func(log_domain, log_level, message, nullptr);
+}
+
+GLogWriterOutput glib_log_writer_func(GLogLevelFlags flags,
+ const GLogField* fields, gsize n_fields,
+ gpointer user_data) {
+ static const GLogWriterFunc sLogWriterDefault =
+ (GLogWriterFunc)dlsym(RTLD_DEFAULT, "g_log_writer_default");
+ for (gsize i = 0; i < n_fields; ++i) {
+ if (!strcmp(fields[i].key, "MESSAGE") && fields[i].length < 0) {
+ HandleGLibMessage(flags,
+ nsDependentCString((const char*)fields[i].value));
+ break;
+ }
+ }
+ return sLogWriterDefault(flags, fields, n_fields, user_data);
+}
+
+# endif
+
+# ifdef SA_SIGINFO
+static void fpehandler(int signum, siginfo_t* si, void* context) {
+ /* Integer divide by zero or integer overflow. */
+ /* Note: FPE_INTOVF is ignored on Intel, PowerPC and SPARC systems. */
+ if (si->si_code == FPE_INTDIV || si->si_code == FPE_INTOVF) {
+ NS_DebugBreak(NS_DEBUG_ABORT, "Divide by zero", nullptr, __FILE__,
+ __LINE__);
+ }
+
+# ifdef XP_MACOSX
+# if defined(__i386__) || defined(__amd64__)
+ ucontext_t* uc = (ucontext_t*)context;
+
+ _STRUCT_FP_CONTROL* ctrl = &uc->uc_mcontext->__fs.__fpu_fcw;
+ ctrl->__invalid = ctrl->__denorm = ctrl->__zdiv = ctrl->__ovrfl =
+ ctrl->__undfl = ctrl->__precis = 1;
+
+ _STRUCT_FP_STATUS* status = &uc->uc_mcontext->__fs.__fpu_fsw;
+ status->__invalid = status->__denorm = status->__zdiv = status->__ovrfl =
+ status->__undfl = status->__precis = status->__stkflt =
+ status->__errsumm = 0;
+
+ uint32_t* mxcsr = &uc->uc_mcontext->__fs.__fpu_mxcsr;
+ *mxcsr |= SSE_EXCEPTION_MASK; /* disable all SSE exceptions */
+ *mxcsr &= ~SSE_STATUS_FLAGS; /* clear all pending SSE exceptions */
+# endif
+# endif
+# if defined(LINUX) && !defined(ANDROID)
+
+# if defined(__i386__)
+ ucontext_t* uc = (ucontext_t*)context;
+ /*
+ * It seems that we have no access to mxcsr on Linux. libc
+ * seems to be translating cw/sw to mxcsr.
+ */
+ unsigned long int* cw = &uc->uc_mcontext.fpregs->cw;
+ *cw |= FPU_EXCEPTION_MASK;
+
+ unsigned long int* sw = &uc->uc_mcontext.fpregs->sw;
+ *sw &= ~FPU_STATUS_FLAGS;
+# endif
+# if defined(__amd64__)
+ ucontext_t* uc = (ucontext_t*)context;
+
+ uint16_t* cw = &uc->uc_mcontext.fpregs->cwd;
+ *cw |= FPU_EXCEPTION_MASK;
+
+ uint16_t* sw = &uc->uc_mcontext.fpregs->swd;
+ *sw &= ~FPU_STATUS_FLAGS;
+
+ uint32_t* mxcsr = &uc->uc_mcontext.fpregs->mxcsr;
+ *mxcsr |= SSE_EXCEPTION_MASK; /* disable all SSE exceptions */
+ *mxcsr &= ~SSE_STATUS_FLAGS; /* clear all pending SSE exceptions */
+# endif
+# endif
+# ifdef SOLARIS
+ ucontext_t* uc = (ucontext_t*)context;
+
+# if defined(__i386)
+ uint32_t* cw = &uc->uc_mcontext.fpregs.fp_reg_set.fpchip_state.state[0];
+ *cw |= FPU_EXCEPTION_MASK;
+
+ uint32_t* sw = &uc->uc_mcontext.fpregs.fp_reg_set.fpchip_state.state[1];
+ *sw &= ~FPU_STATUS_FLAGS;
+
+ /* address of the instruction that caused the exception */
+ uint32_t* ip = &uc->uc_mcontext.fpregs.fp_reg_set.fpchip_state.state[3];
+ uc->uc_mcontext.gregs[REG_PC] = *ip;
+# endif
+# if defined(__amd64__)
+ uint16_t* cw = &uc->uc_mcontext.fpregs.fp_reg_set.fpchip_state.cw;
+ *cw |= FPU_EXCEPTION_MASK;
+
+ uint16_t* sw = &uc->uc_mcontext.fpregs.fp_reg_set.fpchip_state.sw;
+ *sw &= ~FPU_STATUS_FLAGS;
+
+ uint32_t* mxcsr = &uc->uc_mcontext.fpregs.fp_reg_set.fpchip_state.mxcsr;
+ *mxcsr |= SSE_EXCEPTION_MASK; /* disable all SSE exceptions */
+ *mxcsr &= ~SSE_STATUS_FLAGS; /* clear all pending SSE exceptions */
+# endif
+# endif
+}
+# endif
+
+void InstallSignalHandlers(const char* aProgname) {
+# if defined(CRAWL_STACK_ON_SIGSEGV)
+ if (aProgname) {
+ const char* tmp = strdup(aProgname);
+ if (tmp) {
+ gProgname = tmp;
+ }
+ }
+# endif // CRAWL_STACK_ON_SIGSEGV
+
+ const char* gdbSleep = PR_GetEnv("MOZ_GDB_SLEEP");
+ if (gdbSleep && *gdbSleep) {
+ unsigned int s;
+ if (1 == sscanf(gdbSleep, "%u", &s)) {
+ _gdb_sleep_duration = s;
+ }
+ }
+
+# if defined(CRAWL_STACK_ON_SIGSEGV)
+ if (!getenv("XRE_NO_WINDOWS_CRASH_DIALOG")) {
+ void (*crap_handler)(int) = GeckoProcessType_Default != XRE_GetProcessType()
+ ? child_ah_crap_handler
+ : ah_crap_handler;
+ signal(SIGSEGV, crap_handler);
+ signal(SIGILL, crap_handler);
+ signal(SIGABRT, crap_handler);
+ }
+# endif // CRAWL_STACK_ON_SIGSEGV
+
+# ifdef SA_SIGINFO
+ /* Install a handler for floating point exceptions and disable them if they
+ * occur. */
+ struct sigaction sa, osa;
+ sa.sa_flags = SA_ONSTACK | SA_RESTART | SA_SIGINFO;
+ sa.sa_sigaction = fpehandler;
+ sigemptyset(&sa.sa_mask);
+ sigaction(SIGFPE, &sa, &osa);
+# endif
+
+ if (!XRE_IsParentProcess()) {
+ /*
+ * If the user is debugging a Gecko parent process in gdb and hits ^C to
+ * suspend, a SIGINT signal will be sent to the child. We ignore this signal
+ * so the child isn't killed.
+ */
+ signal(SIGINT, SIG_IGN);
+ }
+
+# if defined(DEBUG) && defined(LINUX)
+ const char* memLimit = PR_GetEnv("MOZ_MEM_LIMIT");
+ if (memLimit && *memLimit) {
+ long m = atoi(memLimit);
+ m *= (1024 * 1024);
+ struct rlimit r;
+ r.rlim_cur = m;
+ r.rlim_max = m;
+ setrlimit(RLIMIT_AS, &r);
+ }
+# endif
+
+# ifdef MOZ_WIDGET_GTK
+ // Override the default glib logging function to intercept some crashes that
+ // are uninterceptable otherwise. Also, when XPCOM_DEBUG_BREAK is set, we can
+ // also get stacks for them, so we get stacks for it too.
+ //
+ // If we can hook via g_log_set_writer_func, then we don't need to hook via
+ // g_log_set_default_handler, because the GTK default handler uses structured
+ // logging and thus will end up in our log writer function anyways.
+ static const auto sSetLogWriter =
+ (void (*)(GLogWriterFunc, gpointer, GDestroyNotify))dlsym(
+ RTLD_DEFAULT, "g_log_set_writer_func");
+ if (sSetLogWriter) {
+ sSetLogWriter(glib_log_writer_func, nullptr, nullptr);
+ } else {
+ orig_log_func = g_log_set_default_handler(glib_log_func, nullptr);
+ }
+# endif
+}
+
+#elif XP_WIN
+
+# include <windows.h>
+
+# ifdef _M_IX86
+/*
+ * WinNT.h prior to SDK7 does not expose the structure of the ExtendedRegisters
+ * for ia86. We known that MxCsr is at offset 0x18 and is a DWORD.
+ */
+# define MXCSR(ctx) (*(DWORD*)(((BYTE*)(ctx)->ExtendedRegisters) + 0x18))
+# endif
+
+# ifdef _M_X64
+# define MXCSR(ctx) (ctx)->MxCsr
+# endif
+
+# if defined(_M_IX86) || defined(_M_X64)
+
+# ifdef _M_X64
+# define X87CW(ctx) (ctx)->FltSave.ControlWord
+# define X87SW(ctx) (ctx)->FltSave.StatusWord
+# else
+# define X87CW(ctx) (ctx)->FloatSave.ControlWord
+# define X87SW(ctx) (ctx)->FloatSave.StatusWord
+# endif
+
+static LPTOP_LEVEL_EXCEPTION_FILTER gFPEPreviousFilter;
+
+LONG __stdcall FpeHandler(PEXCEPTION_POINTERS pe) {
+ PEXCEPTION_RECORD e = (PEXCEPTION_RECORD)pe->ExceptionRecord;
+ CONTEXT* c = (CONTEXT*)pe->ContextRecord;
+
+ switch (e->ExceptionCode) {
+ case STATUS_FLOAT_DENORMAL_OPERAND:
+ case STATUS_FLOAT_DIVIDE_BY_ZERO:
+ case STATUS_FLOAT_INEXACT_RESULT:
+ case STATUS_FLOAT_INVALID_OPERATION:
+ case STATUS_FLOAT_OVERFLOW:
+ case STATUS_FLOAT_STACK_CHECK:
+ case STATUS_FLOAT_UNDERFLOW:
+ case STATUS_FLOAT_MULTIPLE_FAULTS:
+ case STATUS_FLOAT_MULTIPLE_TRAPS:
+ X87CW(c) |= FPU_EXCEPTION_MASK; /* disable all FPU exceptions */
+ X87SW(c) &= ~FPU_STATUS_FLAGS; /* clear all pending FPU exceptions */
+# ifdef _M_IX86
+ if (c->ContextFlags & CONTEXT_EXTENDED_REGISTERS) {
+# endif
+ MXCSR(c) |= SSE_EXCEPTION_MASK; /* disable all SSE exceptions */
+ MXCSR(c) &= ~SSE_STATUS_FLAGS; /* clear all pending SSE exceptions */
+# ifdef _M_IX86
+ }
+# endif
+ return EXCEPTION_CONTINUE_EXECUTION;
+ }
+ LONG action = EXCEPTION_CONTINUE_SEARCH;
+ if (gFPEPreviousFilter) action = gFPEPreviousFilter(pe);
+
+ return action;
+}
+
+void InstallSignalHandlers(const char* aProgname) {
+ gFPEPreviousFilter = SetUnhandledExceptionFilter(FpeHandler);
+}
+
+# else
+
+void InstallSignalHandlers(const char* aProgname) {}
+
+# endif
+
+#else
+# error No signal handling implementation for this platform.
+#endif