--- /dev/null
+/*
+ * Copyright (C) 2008 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 <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include "private/android_filesystem_config.h"
+#include "cutils/log.h"
+
+void fatal(const char *msg) {
+ fprintf(stderr, "%s", msg);
+ LOG(LOG_ERROR, "logwrapper", "%s", msg);
+ exit(-1);
+}
+
+void usage() {
+ fatal(
+ "Usage: logwrapper [-x] BINARY [ARGS ...]\n"
+ "\n"
+ "Forks and executes BINARY ARGS, redirecting stdout and stderr to\n"
+ "the Android logging system. Tag is set to BINARY, priority is\n"
+ "always LOG_INFO.\n"
+ "\n"
+ "-x: Causes logwrapper to SIGSEGV when BINARY terminates\n"
+ " fault address is set to the status of wait()\n");
+}
+
+void parent(const char *tag, int seg_fault_on_exit, int parent_read) {
+ int status;
+ char buffer[4096];
+
+ int a = 0; // start index of unprocessed data
+ int b = 0; // end index of unprocessed data
+ int sz;
+ while ((sz = read(parent_read, &buffer[b], sizeof(buffer) - 1 - b)) > 0) {
+
+ sz += b;
+ // Log one line at a time
+ for (b = 0; b < sz; b++) {
+ if (buffer[b] == '\r') {
+ buffer[b] = '\0';
+ } else if (buffer[b] == '\n') {
+ buffer[b] = '\0';
+ LOG(LOG_INFO, tag, "%s", &buffer[a]);
+ a = b + 1;
+ }
+ }
+
+ if (a == 0 && b == sizeof(buffer) - 1) {
+ // buffer is full, flush
+ buffer[b] = '\0';
+ LOG(LOG_INFO, tag, "%s", &buffer[a]);
+ b = 0;
+ } else if (a != b) {
+ // Keep left-overs
+ b -= a;
+ memmove(buffer, &buffer[a], b);
+ a = 0;
+ } else {
+ a = 0;
+ b = 0;
+ }
+
+ }
+ // Flush remaining data
+ if (a != b) {
+ buffer[b] = '\0';
+ LOG(LOG_INFO, tag, "%s", &buffer[a]);
+ }
+ status = 0xAAAA;
+ if (wait(&status) != -1) { // Wait for child
+ if (WIFEXITED(status))
+ LOG(LOG_INFO, "logwrapper", "%s terminated by exit(%d)", tag,
+ WEXITSTATUS(status));
+ else if (WIFSIGNALED(status))
+ LOG(LOG_INFO, "logwrapper", "%s terminated by signal %d", tag,
+ WTERMSIG(status));
+ else if (WIFSTOPPED(status))
+ LOG(LOG_INFO, "logwrapper", "%s stopped by signal %d", tag,
+ WSTOPSIG(status));
+ } else
+ LOG(LOG_INFO, "logwrapper", "%s wait() failed: %s (%d)", tag,
+ strerror(errno), errno);
+ if (seg_fault_on_exit)
+ *(int *)status = 0; // causes SIGSEGV with fault_address = status
+}
+
+void child(int argc, char* argv[]) {
+ // create null terminated argv_child array
+ char* argv_child[argc + 1];
+ memcpy(argv_child, argv, argc * sizeof(char *));
+ argv_child[argc] = NULL;
+
+ if (execvp(argv_child[0], argv_child)) {
+ LOG(LOG_ERROR, "logwrapper",
+ "executing %s failed: %s\n", argv_child[0], strerror(errno));
+ exit(-1);
+ }
+}
+
+int main(int argc, char* argv[]) {
+ pid_t pid;
+ int seg_fault_on_exit = 0;
+
+ int parent_ptty;
+ int child_ptty;
+ char *child_devname = NULL;
+
+ if (argc < 2) {
+ usage();
+ }
+
+ if (strncmp(argv[1], "-d", 2) == 0) {
+ seg_fault_on_exit = 1;
+ argc--;
+ argv++;
+ }
+
+ if (argc < 2) {
+ usage();
+ }
+
+ /* 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");
+ }
+
+ if (grantpt(parent_ptty) || unlockpt(parent_ptty) ||
+ ((child_devname = (char*)ptsname(parent_ptty)) == 0)) {
+ fatal("Problem with /dev/ptmx\n");
+ }
+
+ pid = fork();
+ if (pid < 0) {
+ fatal("Failed to fork\n");
+ } else if (pid == 0) {
+ child_ptty = open(child_devname, O_RDWR);
+ if (child_ptty < 0) {
+ fatal("Problem with child ptty\n");
+ }
+
+ // redirect stdout and stderr
+ close(parent_ptty);
+ dup2(child_ptty, 1);
+ dup2(child_ptty, 2);
+ close(child_ptty);
+
+ child(argc - 1, &argv[1]);
+
+ } else {
+ // switch user and group to "log"
+ // this may fail if we are not root,
+ // but in that case switching user/group is unnecessary
+ setgid(AID_LOG);
+ setuid(AID_LOG);
+
+ parent(argv[1], seg_fault_on_exit, parent_ptty);
+ }
+
+ return 0;
+}
OSDN Git Service
