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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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