| /* |
| * Copyright (C) 2007 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. |
| */ |
| |
| #define LOG_TAG "ProcessManager" |
| |
| #include <sys/resource.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| #include <fcntl.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <errno.h> |
| |
| #include "jni.h" |
| #include "JNIHelp.h" |
| #include "JniConstants.h" |
| #include "ScopedLocalRef.h" |
| #include "cutils/log.h" |
| |
| /** Close all open fds > 2 (i.e. everything but stdin/out/err), != skipFd. */ |
| static void closeNonStandardFds(int skipFd1, int skipFd2) { |
| // TODO: rather than close all these non-open files, we could look in /proc/self/fd. |
| rlimit rlimit; |
| getrlimit(RLIMIT_NOFILE, &rlimit); |
| const int max_fd = rlimit.rlim_max; |
| for (int fd = 3; fd < max_fd; ++fd) { |
| if (fd != skipFd1 && fd != skipFd2) { |
| close(fd); |
| } |
| } |
| } |
| |
| #define PIPE_COUNT (4) // number of pipes used to communicate with child proc |
| |
| /** Closes all pipes in the given array. */ |
| static void closePipes(int pipes[], int skipFd) { |
| for (int i = 0; i < PIPE_COUNT * 2; i++) { |
| int fd = pipes[i]; |
| if (fd == -1) { |
| return; |
| } |
| if (fd != skipFd) { |
| close(pipes[i]); |
| } |
| } |
| } |
| |
| /** Executes a command in a child process. */ |
| static pid_t executeProcess(JNIEnv* env, char** commands, char** environment, |
| const char* workingDirectory, jobject inDescriptor, |
| jobject outDescriptor, jobject errDescriptor, |
| jboolean redirectErrorStream) { |
| |
| // Keep track of the system properties fd so we don't close it. |
| int androidSystemPropertiesFd = -1; |
| char* fdString = getenv("ANDROID_PROPERTY_WORKSPACE"); |
| if (fdString) { |
| androidSystemPropertiesFd = atoi(fdString); |
| } |
| |
| // Create 4 pipes: stdin, stdout, stderr, and an exec() status pipe. |
| int pipes[PIPE_COUNT * 2] = { -1, -1, -1, -1, -1, -1, -1, -1 }; |
| for (int i = 0; i < PIPE_COUNT; i++) { |
| if (pipe(pipes + i * 2) == -1) { |
| jniThrowIOException(env, errno); |
| closePipes(pipes, -1); |
| return -1; |
| } |
| } |
| int stdinIn = pipes[0]; |
| int stdinOut = pipes[1]; |
| int stdoutIn = pipes[2]; |
| int stdoutOut = pipes[3]; |
| int stderrIn = pipes[4]; |
| int stderrOut = pipes[5]; |
| int statusIn = pipes[6]; |
| int statusOut = pipes[7]; |
| |
| pid_t childPid = fork(); |
| |
| // If fork() failed... |
| if (childPid == -1) { |
| jniThrowIOException(env, errno); |
| closePipes(pipes, -1); |
| return -1; |
| } |
| |
| // If this is the child process... |
| if (childPid == 0) { |
| /* |
| * Note: We cannot malloc() or free() after this point! |
| * A no-longer-running thread may be holding on to the heap lock, and |
| * an attempt to malloc() or free() would result in deadlock. |
| */ |
| |
| // Replace stdin, out, and err with pipes. |
| dup2(stdinIn, 0); |
| dup2(stdoutOut, 1); |
| if (redirectErrorStream) { |
| dup2(stdoutOut, 2); |
| } else { |
| dup2(stderrOut, 2); |
| } |
| |
| // Close all but statusOut. This saves some work in the next step. |
| closePipes(pipes, statusOut); |
| |
| // Make statusOut automatically close if execvp() succeeds. |
| fcntl(statusOut, F_SETFD, FD_CLOEXEC); |
| |
| // Close remaining unwanted open fds. |
| closeNonStandardFds(statusOut, androidSystemPropertiesFd); |
| |
| // Switch to working directory. |
| if (workingDirectory != NULL) { |
| if (chdir(workingDirectory) == -1) { |
| goto execFailed; |
| } |
| } |
| |
| // Set up environment. |
| if (environment != NULL) { |
| extern char** environ; // Standard, but not in any header file. |
| environ = environment; |
| } |
| |
| // Execute process. By convention, the first argument in the arg array |
| // should be the command itself. In fact, I get segfaults when this |
| // isn't the case. |
| execvp(commands[0], commands); |
| |
| // If we got here, execvp() failed or the working dir was invalid. |
| execFailed: |
| int error = errno; |
| write(statusOut, &error, sizeof(int)); |
| close(statusOut); |
| exit(error); |
| } |
| |
| // This is the parent process. |
| |
| // Close child's pipe ends. |
| close(stdinIn); |
| close(stdoutOut); |
| close(stderrOut); |
| close(statusOut); |
| |
| // Check status pipe for an error code. If execvp() succeeds, the other |
| // end of the pipe should automatically close, in which case, we'll read |
| // nothing. |
| int result; |
| int count = read(statusIn, &result, sizeof(int)); |
| close(statusIn); |
| if (count > 0) { |
| jniThrowIOException(env, result); |
| |
| close(stdoutIn); |
| close(stdinOut); |
| close(stderrIn); |
| |
| return -1; |
| } |
| |
| // Fill in file descriptor wrappers. |
| jniSetFileDescriptorOfFD(env, inDescriptor, stdoutIn); |
| jniSetFileDescriptorOfFD(env, outDescriptor, stdinOut); |
| jniSetFileDescriptorOfFD(env, errDescriptor, stderrIn); |
| |
| return childPid; |
| } |
| |
| /** Converts a Java String[] to a 0-terminated char**. */ |
| static char** convertStrings(JNIEnv* env, jobjectArray javaArray) { |
| if (javaArray == NULL) { |
| return NULL; |
| } |
| |
| jsize length = env->GetArrayLength(javaArray); |
| char** array = new char*[length + 1]; |
| array[length] = 0; |
| for (jsize i = 0; i < length; ++i) { |
| ScopedLocalRef<jstring> javaEntry(env, reinterpret_cast<jstring>(env->GetObjectArrayElement(javaArray, i))); |
| // We need to pass these strings to const-unfriendly code. |
| char* entry = const_cast<char*>(env->GetStringUTFChars(javaEntry.get(), NULL)); |
| array[i] = entry; |
| } |
| |
| return array; |
| } |
| |
| /** Frees a char** which was converted from a Java String[]. */ |
| static void freeStrings(JNIEnv* env, jobjectArray javaArray, char** array) { |
| if (javaArray == NULL) { |
| return; |
| } |
| |
| jsize length = env->GetArrayLength(javaArray); |
| for (jsize i = 0; i < length; ++i) { |
| ScopedLocalRef<jstring> javaEntry(env, reinterpret_cast<jstring>(env->GetObjectArrayElement(javaArray, i))); |
| env->ReleaseStringUTFChars(javaEntry.get(), array[i]); |
| } |
| |
| delete[] array; |
| } |
| |
| /** |
| * Converts Java String[] to char** and delegates to executeProcess(). |
| */ |
| static pid_t ProcessManager_exec(JNIEnv* env, jclass, jobjectArray javaCommands, |
| jobjectArray javaEnvironment, jstring javaWorkingDirectory, |
| jobject inDescriptor, jobject outDescriptor, jobject errDescriptor, |
| jboolean redirectErrorStream) { |
| |
| // Copy commands into char*[]. |
| char** commands = convertStrings(env, javaCommands); |
| |
| // Extract working directory string. |
| const char* workingDirectory = NULL; |
| if (javaWorkingDirectory != NULL) { |
| workingDirectory = env->GetStringUTFChars(javaWorkingDirectory, NULL); |
| } |
| |
| // Convert environment array. |
| char** environment = convertStrings(env, javaEnvironment); |
| |
| pid_t result = executeProcess(env, commands, environment, workingDirectory, |
| inDescriptor, outDescriptor, errDescriptor, redirectErrorStream); |
| |
| // Temporarily clear exception so we can clean up. |
| jthrowable exception = env->ExceptionOccurred(); |
| env->ExceptionClear(); |
| |
| freeStrings(env, javaEnvironment, environment); |
| |
| // Clean up working directory string. |
| if (javaWorkingDirectory != NULL) { |
| env->ReleaseStringUTFChars(javaWorkingDirectory, workingDirectory); |
| } |
| |
| freeStrings(env, javaCommands, commands); |
| |
| // Re-throw exception if present. |
| if (exception != NULL) { |
| if (env->Throw(exception) < 0) { |
| ALOGE("Error rethrowing exception!"); |
| } |
| } |
| |
| return result; |
| } |
| |
| static JNINativeMethod methods[] = { |
| NATIVE_METHOD(ProcessManager, exec, "([Ljava/lang/String;[Ljava/lang/String;Ljava/lang/String;Ljava/io/FileDescriptor;Ljava/io/FileDescriptor;Ljava/io/FileDescriptor;Z)I"), |
| }; |
| void register_java_lang_ProcessManager(JNIEnv* env) { |
| jniRegisterNativeMethods(env, "java/lang/ProcessManager", methods, NELEM(methods)); |
| } |