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Commit 74a7b91c authored by Rom Lemarchand's avatar Rom Lemarchand
Browse files

liblogwrap: lock android_fork_execvp 

Add a lock around android_fork_execvp to ensure no two threads can
execute it at the same time.

This is to help with http://b/8333626

Change-Id: I75d087a74b58f5b8e878675b301200f54d976fb2
parent 39b7fdea

logwrapper/logwrap.c

+11 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <fcntl.h>

#include <libgen.h>

#include <stdbool.h>

#include <pthread.h>



#include <logwrap/logwrap.h>

#include "private/android_filesystem_config.h"
@@ -35,6 +36,7 @@ 
#define ARRAY_SIZE(x)   (sizeof(x) / sizeof(*(x)))



static int signal_fd_write;

static pthread_mutex_t fd_mutex = PTHREAD_MUTEX_INITIALIZER;



#define ERROR(fmt, args...)                                                   \

do {                                                                          \
@@ -204,6 +206,12 @@ int android_fork_execvp(int argc, char* argv[], int *status, bool ignore_int_qui 
    int sockets[2];

    int rc = 0;



    rc = pthread_mutex_lock(&fd_mutex);

    if (rc) {

        ERROR("failed to lock signal_fd mutex\n");

        goto err_lock;

    }



    /* Use ptty instead of socketpair so that STDOUT is not buffered */

    parent_ptty = open("/dev/ptmx", O_RDWR);

    if (parent_ptty < 0) {
@@ -231,6 +239,7 @@ int android_fork_execvp(int argc, char* argv[], int *status, bool ignore_int_qui 
        rc = -1;

        goto err_fork;

    } else if (pid == 0) {

        pthread_mutex_unlock(&fd_mutex);

        pthread_sigmask(SIG_SETMASK, &oldset, NULL);

        close(parent_ptty);
@@ -299,5 +308,7 @@ err_fork: 
err_ptty:

    close(parent_ptty);

err_open:

    pthread_mutex_unlock(&fd_mutex);

err_lock:

    return rc;

}