133 lines
3.4 KiB
C
133 lines
3.4 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <string.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include "private/android_filesystem_config.h"
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#include "cutils/log.h"
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void fatal(const char *msg) {
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fprintf(stderr, msg);
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LOG(LOG_ERROR, "logwrapper", msg);
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exit(-1);
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}
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void usage() {
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fatal(
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"Usage: logwrapper BINARY [ARGS ...]\n"
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"\n"
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"Forks and executes BINARY ARGS, redirecting stdout and stderr to\n"
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"the Android logging system. Tag is set to BINARY, priority is\n"
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"always LOG_INFO.\n");
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}
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void parent(const char *tag, int parent_read) {
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int status;
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char buffer[1024];
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int a = 0; // start index of unprocessed data
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int b = 0; // end index of unprocessed data
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int sz;
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while ((sz = read(parent_read, &buffer[b], 1023 - b)) > 0) {
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// Log one line at a time
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for (b = a; b < sz; b++) {
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if (buffer[b] == '\n') {
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buffer[b] = '\0';
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LOG(LOG_INFO, tag, &buffer[a]);
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a = b + 1;
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}
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}
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if (a == 0 && b == 1023) {
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// buffer is full, flush
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buffer[b] = '\0';
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LOG(LOG_INFO, tag, &buffer[a]);
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b = 0;
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} else {
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// Keep left-overs
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b = sz - a;
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memmove(buffer, &buffer[a], b);
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a = 0;
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}
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}
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// Flush remaining data
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if (a != b) {
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buffer[b] = '\0';
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LOG(LOG_INFO, tag, &buffer[a]);
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}
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wait(&status); // Wait for child
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}
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void child(int argc, char* argv[]) {
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// create null terminated argv_child array
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char* argv_child[argc + 1];
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memcpy(argv_child, argv, argc * sizeof(char *));
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argv_child[argc] = NULL;
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if (execvp(argv_child[0], argv_child)) {
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LOG(LOG_ERROR, "logwrapper",
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"executing %s failed: %s\n", argv_child[0], strerror(errno));
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exit(-1);
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}
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}
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int main(int argc, char* argv[]) {
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pid_t pid;
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int pipe_fds[2];
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int *parent_read = &pipe_fds[0];
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int *child_write = &pipe_fds[1];
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if (argc < 2) {
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usage();
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}
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if (pipe(pipe_fds) < 0) {
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fatal("Cannot create pipe\n");
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}
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pid = fork();
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if (pid < 0) {
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fatal("Failed to fork\n");
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} else if (pid == 0) {
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// redirect stdout and stderr
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close(*parent_read);
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dup2(*child_write, 1);
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dup2(*child_write, 2);
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close(*child_write);
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child(argc - 1, &argv[1]);
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} else {
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close(*child_write);
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// switch user and group to "log"
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// this may fail if we are not root,
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// but in that case switching user/group is unnecessary
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setgid(AID_LOG);
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setuid(AID_LOG);
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parent(argv[1], *parent_read);
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}
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return 0;
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}
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