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Commit 5f2ff6a9 authored by Christopher Ferris's avatar Christopher Ferris
Browse files

Add timed versions of stack dumping functions. 

Under some unknown circumstances, debuggerd could become unresponsive.
If you try and take a bugreport during this time, it will hang forever.
Adding functions that have a timeout will allow dumpstate to stop if
dumping is taking too long.

Bug: 18766581
Change-Id: I85053b8dcfe6224e2b64b4d8f7f2ef448b3cda34
parent f2bd3fdd

include/cutils/debugger.h

+15 −0
Original line number Diff line number Diff line
@@ -64,11 +64,26 @@ typedef struct { 
 */

int dump_tombstone(pid_t tid, char* pathbuf, size_t pathlen);



/* Dumps a process backtrace, registers, and stack to a tombstone file (requires root).

 * Stores the tombstone path in the provided buffer.

 * If reading debugger data from debuggerd ever takes longer than timeout_secs

 * seconds, then stop and return an error.

 * Returns 0 on success, -1 on error.

 */

int dump_tombstone_timeout(pid_t tid, char* pathbuf, size_t pathlen, int timeout_secs);



/* Dumps a process backtrace only to the specified file (requires root).

 * Returns 0 on success, -1 on error.

 */

int dump_backtrace_to_file(pid_t tid, int fd);



/* Dumps a process backtrace only to the specified file (requires root).

 * If reading debugger data from debuggerd ever takes longer than timeout_secs

 * seconds, then stop and return an error.

 * Returns 0 on success, -1 on error.

 */

int dump_backtrace_to_file_timeout(pid_t tid, int fd, int timeout_secs);



#ifdef __cplusplus

}

#endif

libcutils/debugger.c

+29 −3
Original line number Diff line number Diff line
@@ -19,11 +19,16 @@ 
#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <unistd.h>



#include <cutils/debugger.h>

#include <cutils/sockets.h>



#define LOG_TAG "DEBUG"

#include <log/log.h>



#if defined(__LP64__)

#include <elf.h>
@@ -64,7 +69,7 @@ static int send_request(int sock_fd, void* msg_ptr, size_t msg_len) { 
  return result;

}



static int make_dump_request(debugger_action_t action, pid_t tid) {

static int make_dump_request(debugger_action_t action, pid_t tid, int timeout_secs) {

  const char* socket_name;

  debugger_msg_t msg;

  size_t msg_len;
@@ -98,6 +103,19 @@ static int make_dump_request(debugger_action_t action, pid_t tid) { 
    return -1;

  }



  if (timeout_secs > 0) {

    struct timeval tm;

    tm.tv_sec = timeout_secs;

    tm.tv_usec = 0;

    if (setsockopt(sock_fd, SOL_SOCKET, SO_RCVTIMEO, &tm, sizeof(tm)) == -1) {

      ALOGE("WARNING: Cannot set receive timeout value on socket: %s", strerror(errno));

    }



    if (setsockopt(sock_fd, SOL_SOCKET, SO_SNDTIMEO, &tm, sizeof(tm)) == -1) {

      ALOGE("WARNING: Cannot set send timeout value on socket: %s", strerror(errno));

    }

  }



  if (send_request(sock_fd, msg_ptr, msg_len) < 0) {

    TEMP_FAILURE_RETRY(close(sock_fd));

    return -1;
@@ -107,7 +125,11 @@ static int make_dump_request(debugger_action_t action, pid_t tid) { 
}



int dump_backtrace_to_file(pid_t tid, int fd) {

  int sock_fd = make_dump_request(DEBUGGER_ACTION_DUMP_BACKTRACE, tid);

  return dump_backtrace_to_file_timeout(tid, fd, 0);

}



int dump_backtrace_to_file_timeout(pid_t tid, int fd, int timeout_secs) {

  int sock_fd = make_dump_request(DEBUGGER_ACTION_DUMP_BACKTRACE, tid, timeout_secs);

  if (sock_fd < 0) {

    return -1;

  }
@@ -127,7 +149,11 @@ int dump_backtrace_to_file(pid_t tid, int fd) { 
}



int dump_tombstone(pid_t tid, char* pathbuf, size_t pathlen) {

  int sock_fd = make_dump_request(DEBUGGER_ACTION_DUMP_TOMBSTONE, tid);

  return dump_tombstone_timeout(tid, pathbuf, pathlen, 0);

}



int dump_tombstone_timeout(pid_t tid, char* pathbuf, size_t pathlen, int timeout_secs) {

  int sock_fd = make_dump_request(DEBUGGER_ACTION_DUMP_TOMBSTONE, tid, timeout_secs);

  if (sock_fd < 0) {

    return -1;

  }