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Commit 435e84b9 authored by yuanhao's avatar yuanhao Committed by Anton Hansson
Browse files

Fix "zygote is killed by signal 1" 



Ignore the signal SIGHUP in Zygote and all its forks.

Bug:71965619
Test: manual

Change-Id: I7987bb044d97ae21ec27beca6e9aefcbe77197f5
Signed-off-by: default avataryuanhao <yuanhao@xiaomi.com>
parent 4db2d469

core/jni/com_android_internal_os_Zygote.cpp

+28 −14
Original line number Diff line number Diff line
@@ -141,32 +141,45 @@ static void SigChldHandler(int /*signal_number*/) { 
  errno = saved_errno;

}



// Configures the SIGCHLD handler for the zygote process. This is configured

// very late, because earlier in the runtime we may fork() and exec()

// other processes, and we want to waitpid() for those rather than

// Configures the SIGCHLD/SIGHUP handlers for the zygote process. This is

// configured very late, because earlier in the runtime we may fork() and

// exec() other processes, and we want to waitpid() for those rather than

// have them be harvested immediately.

//

// Ignore SIGHUP because all processes forked by the zygote are in the same

// process group as the zygote and we don't want to be notified if we become

// an orphaned group and have one or more stopped processes. This is not a

// theoretical concern :

// - we can become an orphaned group if one of our direct descendants forks

//   and is subsequently killed before its children.

// - crash_dump routinely STOPs the process it's tracing.

//

// See issues b/71965619 and b/25567761 for further details.

//

// This ends up being called repeatedly before each fork(), but there's

// no real harm in that.

static void SetSigChldHandler() {

  struct sigaction sa;

  memset(&sa, 0, sizeof(sa));

  sa.sa_handler = SigChldHandler;

static void SetSignalHandlers() {

  struct sigaction sig_chld = {};

  sig_chld.sa_handler = SigChldHandler;



  int err = sigaction(SIGCHLD, &sa, NULL);

  if (err < 0) {

  if (sigaction(SIGCHLD, &sig_chld, NULL) < 0) {

    ALOGW("Error setting SIGCHLD handler: %s", strerror(errno));

  }



  struct sigaction sig_hup = {};

  sig_hup.sa_handler = SIG_IGN;

  if (sigaction(SIGHUP, &sig_hup, NULL) < 0) {

    ALOGW("Error setting SIGHUP handler: %s", strerror(errno));

  }

}



// Sets the SIGCHLD handler back to default behavior in zygote children.

static void UnsetSigChldHandler() {

static void UnsetChldSignalHandler() {

  struct sigaction sa;

  memset(&sa, 0, sizeof(sa));

  sa.sa_handler = SIG_DFL;



  int err = sigaction(SIGCHLD, &sa, NULL);

  if (err < 0) {

  if (sigaction(SIGCHLD, &sa, NULL) < 0) {

    ALOGW("Error unsetting SIGCHLD handler: %s", strerror(errno));

  }

}
@@ -505,7 +518,7 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra 
                                     bool is_system_server, jintArray fdsToClose,

                                     jintArray fdsToIgnore,

                                     jstring instructionSet, jstring dataDir) {

  SetSigChldHandler();

  SetSignalHandlers();



  sigset_t sigchld;

  sigemptyset(&sigchld);
@@ -682,7 +695,8 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra 
    delete se_info;

    delete se_name;



    UnsetSigChldHandler();

    // Unset the SIGCHLD handler, but keep ignoring SIGHUP (rationale in SetSignalHandlers).

    UnsetChldSignalHandler();



    env->CallStaticVoidMethod(gZygoteClass, gCallPostForkChildHooks, runtime_flags,

                              is_system_server, instructionSet);