1 files changed, 450 insertions, 0 deletions

diff --git a/toolkit/xre/nsSigHandlers.cpp b/toolkit/xre/nsSigHandlers.cpp
new file mode 100644
index 0000000000..a9679eab75
--- /dev/null
+++ b/toolkit/xre/nsSigHandlers.cpp
@@ -0,0 +1,450 @@
+/* -*- 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