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- /*
- * Copyright (C) 2011 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #include <unistd.h>
- #include <stdio.h>
- #include "sysdeps.h"
- #define TRACE_TAG TRACE_ADB
- #include "adb.h"
- typedef struct {
- pid_t pid;
- int fd;
- } backup_harvest_params;
- // 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;
- }
- // harvest the child process then close the read end of the socketpair
- static void* backup_child_waiter(void* args) {
- int status;
- backup_harvest_params* params = (backup_harvest_params*) args;
- waitpid(params->pid, &status, 0);
- adb_close(params->fd);
- free(params);
- return NULL;
- }
- /* returns the data socket passing the backup data here for forwarding */
- int backup_service(BackupOperation op, char* args) {
- pid_t pid;
- int s[2];
- char* operation;
- int socketnum;
- // Command string and choice of stdin/stdout for the pipe depend on our invocation
- if (op == BACKUP) {
- operation = "backup";
- socketnum = STDOUT_FILENO;
- } else {
- operation = "restore";
- socketnum = STDIN_FILENO;
- }
- D("backup_service(%s, %s)\n", operation, args);
- // set up the pipe from the subprocess to here
- // parent will read s[0]; child will write s[1]
- 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) {
- // failure
- D("can't fork for %s\n", operation);
- fprintf(stderr, "unable to fork for %s\n", operation);
- adb_close(s[0]);
- adb_close(s[1]);
- return -1;
- }
- // 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;
- // 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++;
- if (*p == ':') p++;
- }
- bu_args = (char**) alloca(argc*sizeof(char*) + 1);
- // 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++;
- if (*p == ':') {
- *p = 0;
- p++;
- }
- }
- bu_args[argc] = NULL;
- // 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]);
- // off we go
- execvp("/system/bin/bu", (char * const *)bu_args);
- // oops error - close up shop and go home
- fprintf(stderr, "Unable to exec 'bu', bailing\n");
- exit(-1);
- } else {
- adb_thread_t t;
- backup_harvest_params* params;
- // 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
- params = (backup_harvest_params*) malloc(sizeof(backup_harvest_params));
- params->pid = pid;
- params->fd = s[0];
- if (adb_thread_create(&t, backup_child_waiter, params)) {
- adb_close(s[0]);
- free(params);
- 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
- return s[0];
- }
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