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Commit 99e19664 authored by Rom Lemarchand's avatar Rom Lemarchand
Browse files

logwrap: ensure child exits with _exit 

Always exit the child process with _exit() rather than exit() to ensure none
of the parent's atexit functions get called if the child needs to exit before
calling exec.

Change-Id: I6a75111ef1bb3468c114c98743565471cf82c9dd
parent 83dee8e4

logwrapper/logwrap.c

+19 −20
Original line number Diff line number Diff line
@@ -36,10 +36,17 @@ 


static int signal_fd_write;



static void fatal(const char *msg) {

    fprintf(stderr, "%s", msg);

    ALOG(LOG_ERROR, "logwrapper", "%s", msg);

}

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

do {                                                                          \

    fprintf(stderr, fmt, ## args);                                            \

    ALOG(LOG_ERROR, "logwrapper", fmt, ## args);                              \

} while(0)



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

do {                                                                          \

    ERROR(fmt, ## args);                                                      \

    _exit(-1);                                                                \

} while(0)



static int parent(const char *tag, int parent_read, int signal_fd, pid_t pid,

        int *chld_sts) {
@@ -75,7 +82,7 @@ static int parent(const char *tag, int parent_read, int signal_fd, pid_t pid, 
        if (poll(poll_fds, remote_hung ? 1 : 2, -1) < 0) {

            if (errno == EINTR)

                continue;

            fatal("poll failed\n");

            ERROR("poll failed\n");

            rc = -1;

            goto err_poll;

        }
@@ -166,9 +173,8 @@ static void child(int argc, char* argv[]) { 
    argv_child[argc] = NULL;



    if (execvp(argv_child[0], argv_child)) {

        ALOG(LOG_ERROR, "logwrapper",

            "executing %s failed: %s\n", argv_child[0], strerror(errno));

        exit(-1);

        FATAL_CHILD("executing %s failed: %s\n", argv_child[0],

                strerror(errno));

    }

}
@@ -191,14 +197,14 @@ int logwrap(int argc, char* argv[], int *status) { 
    /* Use ptty instead of socketpair so that STDOUT is not buffered */

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

    if (parent_ptty < 0) {

        fatal("Cannot create parent ptty\n");

        ERROR("Cannot create parent ptty\n");

        rc = -1;

        goto err_open;

    }



    if (grantpt(parent_ptty) || unlockpt(parent_ptty) ||

            ((child_devname = (char*)ptsname(parent_ptty)) == 0)) {

        fatal("Problem with /dev/ptmx\n");

        ERROR("Problem with /dev/ptmx\n");

        rc = -1;

        goto err_ptty;

    }
@@ -209,7 +215,7 @@ int logwrap(int argc, char* argv[], int *status) { 


    pid = fork();

    if (pid < 0) {

        fatal("Failed to fork\n");

        ERROR("Failed to fork\n");

        rc = -1;

        goto err_fork;

    } else if (pid == 0) {
@@ -218,8 +224,7 @@ int logwrap(int argc, char* argv[], int *status) { 


        child_ptty = open(child_devname, O_RDWR);

        if (child_ptty < 0) {

            fatal("Problem with child ptty\n");

            return -1;

            FATAL_CHILD("Problem with child ptty\n");

        }



        // redirect stdout and stderr
@@ -228,8 +233,6 @@ int logwrap(int argc, char* argv[], int *status) { 
        close(child_ptty);



        child(argc, argv);

        fatal("This should never happen\n");

        return -1;

    } else {

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

        chldact.sa_handler = sigchld_handler;
@@ -247,11 +250,7 @@ int logwrap(int argc, char* argv[], int *status) { 


        rc = socketpair(AF_UNIX, SOCK_STREAM, 0, sockets);

        if (rc == -1) {

            char msg[40];



            snprintf(msg, sizeof(msg), "socketpair failed: %d\n", errno);



            fatal(msg);

            ERROR("socketpair failed: %s\n", strerror(errno));

            goto err_socketpair;

        }