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Commit 5b811fa5 authored by Christopher Tate's avatar Christopher Tate
Browse files

Tidy up the end-of-data handling in backup 

* Increase transfer buffer size to 32K
* Add logging about error conditions and fd teardown
* Pass the fd number as a command line option to the 'bu' subprocess
* Properly harvest the 'bu' subprocess after it's done

Change-Id: Id44dde25778ecf43c5604fd9d01d726ba58861e5
parent 352dfdfa

adb/backup_service.c

+42 −7
Original line number Diff line number Diff line
@@ -22,6 +22,23 @@ 
#define TRACE_TAG  TRACE_ADB

#include "adb.h"



// socketpair but do *not* mark as close_on_exec

static int backup_socketpair(int sv[2]) {

    int rc = unix_socketpair( AF_UNIX, SOCK_STREAM, 0, sv );

    if (rc < 0)

        return -1;



    return 0;

}



static void* backup_child_waiter(void* pid_cookie) {

    int status;



    waitpid((pid_t) pid_cookie, &status, 0);

    D("harvested backup/restore child, status=%d\n", status);

    return NULL;

}



/* returns the data socket passing the backup data here for forwarding */

int backup_service(BackupOperation op, char* args) {

    pid_t pid;
@@ -42,12 +59,15 @@ int backup_service(BackupOperation op, char* args) { 


    // set up the pipe from the subprocess to here

    // parent will read s[0]; child will write s[1]

    if (adb_socketpair(s)) {

    if (backup_socketpair(s)) {

        D("can't create backup/restore socketpair\n");

        fprintf(stderr, "unable to create backup/restore socketpair\n");

        return -1;

    }



    D("Backup/restore socket pair: (send=%d, receive=%d)\n", s[1], s[0]);

    close_on_exec(s[0]);    // only the side we hold on to



    // spin off the child process to run the backup command

    pid = fork();

    if (pid < 0) {
@@ -61,12 +81,14 @@ int backup_service(BackupOperation op, char* args) { 


    // Great, we're off and running.

    if (pid == 0) {

        // child -- actually run the backup here

        char* p;

        int argc;

        char portnum[16];

        char** bu_args;



        // child -- actually run the backup here

        argc = 2; // room for the basic 'bu' argv[0] and '[operation]' argv[1]

        // fixed args:  [0] is 'bu', [1] is the port number, [2] is the 'operation' string

        argc = 3;

        for (p = (char*)args; p && *p; ) {

            argc++;

            while (*p && *p != ':') p++;
@@ -74,9 +96,13 @@ int backup_service(BackupOperation op, char* args) { 
        }



        bu_args = (char**) alloca(argc*sizeof(char*) + 1);

        bu_args[0] = "bu";

        bu_args[1] = operation;

        argc = 2;   // run through again to build the argv array



        // run through again to build the argv array

        argc = 0;

        bu_args[argc++] = "bu";

        snprintf(portnum, sizeof(portnum), "%d", s[1]);

        bu_args[argc++] = portnum;

        bu_args[argc++] = operation;

        for (p = (char*)args; p && *p; ) {

            bu_args[argc++] = p;

            while (*p && *p != ':') p++;
@@ -90,7 +116,6 @@ int backup_service(BackupOperation op, char* args) { 
        // Close the half of the socket that we don't care about, route 'bu's console

        // to the output socket, and off we go

        adb_close(s[0]);

        dup2(s[1], socketnum);



        // off we go

        execvp("/system/bin/bu", (char * const *)bu_args);
@@ -98,8 +123,18 @@ int backup_service(BackupOperation op, char* args) { 
        fprintf(stderr, "Unable to exec 'bu', bailing\n");

        exit(-1);

    } else {

        adb_thread_t t;



        // parent, i.e. adbd -- close the sending half of the socket

        D("fork() returned pid %d\n", pid);

        adb_close(s[1]);



        // spin a thread to harvest the child process

        if (adb_thread_create(&t, backup_child_waiter, (void*)pid)) {

            adb_close(s[0]);

            D("Unable to create child harvester\n");

            return -1;

        }

    }



    // we'll be reading from s[0] as the data is sent by the child process

adb/commandline.c

+9 −3
Original line number Diff line number Diff line
@@ -239,18 +239,23 @@ static void read_and_dump(int fd) 
}



static void copy_to_file(int inFd, int outFd) {

    char buf[4096];

    const size_t BUFSIZE = 32 * 1024;

    char* buf = (char*) malloc(BUFSIZE);

    int len;

    long total = 0;



    D("copy_to_file(%d -> %d)\n", inFd, outFd);

    for (;;) {

        len = adb_read(inFd, buf, sizeof(buf));

        len = adb_read(inFd, buf, BUFSIZE);

        if (len == 0) {

            D("copy_to_file() : read 0 bytes; exiting\n");

            break;

        }

        if (len < 0) {

            if (errno == EINTR) continue;

            if (errno == EINTR) {

                D("copy_to_file() : EINTR, retrying\n");

                continue;

            }

            D("copy_to_file() : error %d\n", errno);

            break;

        }
@@ -258,6 +263,7 @@ static void copy_to_file(int inFd, int outFd) { 
        total += len;

    }

    D("copy_to_file() finished after %lu bytes\n", total);

    free(buf);

}



static void *stdin_read_thread(void *x)

adb/sockets.c

+3 −0
Original line number Diff line number Diff line
@@ -288,6 +288,7 @@ static void local_socket_event_func(int fd, unsigned ev, void *_s) 
                    if(errno == EAGAIN) return;

                    if(errno == EINTR) continue;

                }

                D(" closing after write because r=%d and errno is %d\n", r, errno);

                s->close(s);

                return;

            }
@@ -303,6 +304,7 @@ static void local_socket_event_func(int fd, unsigned ev, void *_s) 
            ** we can now destroy it.

            */

        if (s->closing) {

            D(" closing because 'closing' is set after write\n");

            s->close(s);

            return;

        }
@@ -372,6 +374,7 @@ static void local_socket_event_func(int fd, unsigned ev, void *_s) 
        }

        /* Don't allow a forced eof if data is still there */

        if((s->fde.force_eof && !r) || is_eof) {

            D(" closing because is_eof=%d r=%d s->fde.force_eof=%d\n", is_eof, r, s->fde.force_eof);

            s->close(s);

        }

    }