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/*
* 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"
#include "cutils/sched_policy.h"
int parent(const char *tag, 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';
ALOG(LOG_INFO, tag, "%s", &buffer[a]);
a = b + 1;
}
}
if (a == 0 && b == sizeof(buffer) - 1) {
// buffer is full, flush
buffer[b] = '\0';
ALOG(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';
ALOG(LOG_INFO, tag, "%s", &buffer[a]);
}
status = 0xAAAA;
if (wait(&status) != -1) { // Wait for child
if (WIFEXITED(status)) {
if (WEXITSTATUS(status) != 0) {
ALOG(LOG_INFO, "logwrapper", "%s terminated by exit(%d)", tag,
WEXITSTATUS(status));
}
return WEXITSTATUS(status);
} else if (WIFSIGNALED(status))
ALOG(LOG_INFO, "logwrapper", "%s terminated by signal %d", tag,
WTERMSIG(status));
else if (WIFSTOPPED(status))
ALOG(LOG_INFO, "logwrapper", "%s stopped by signal %d", tag,
WSTOPSIG(status));
} else
ALOG(LOG_INFO, "logwrapper", "%s wait() failed: %s (%d)", tag,
strerror(errno), errno);
return -EAGAIN;
}
void child(int argc, const char**argv) {
// create null terminated argv_child array
char* argv_child[argc + 1];
memcpy(argv_child, argv, argc * sizeof(char *));
argv_child[argc] = NULL;
// XXX: PROTECT FROM VIKING KILLER
if (execv(argv_child[0], argv_child)) {
ALOG(LOG_ERROR, "logwrapper",
"executing %s failed: %s", argv_child[0], strerror(errno));
exit(-1);
}
}
int logwrap(int argc, const char* argv[], int background)
{
pid_t pid;
int parent_ptty;
int child_ptty;
char *child_devname = NULL;
/* Use ptty instead of socketpair so that STDOUT is not buffered */
parent_ptty = open("/dev/ptmx", O_RDWR);
if (parent_ptty < 0) {
ALOG(LOG_ERROR, "logwrapper", "Cannot create parent ptty");
return -errno;
}
if (grantpt(parent_ptty) || unlockpt(parent_ptty) ||
((child_devname = (char*)ptsname(parent_ptty)) == 0)) {
close(parent_ptty);
ALOG(LOG_ERROR, "logwrapper", "Problem with /dev/ptmx");
return -1;
}
pid = fork();
if (pid < 0) {
close(parent_ptty);
ALOG(LOG_ERROR, "logwrapper", "Failed to fork");
return -errno;
} else if (pid == 0) {
/*
* Child
*/
child_ptty = open(child_devname, O_RDWR);
if (child_ptty < 0) {
close(parent_ptty);
ALOG(LOG_ERROR, "logwrapper", "Problem with child ptty");
return -errno;
}
// redirect stdout and stderr
close(parent_ptty);
dup2(child_ptty, 1);
dup2(child_ptty, 2);
close(child_ptty);
if (background) {
int err = set_sched_policy(getpid(), SP_BACKGROUND);
if (err < 0) {
ALOG(LOG_WARN, "logwrapper",
"Unable to background process (%s)", strerror(-err));
}
}
child(argc, argv);
} else {
/*
* Parent
*/
int rc = parent(argv[0], parent_ptty);
close(parent_ptty);
return rc;
}
return 0;
}
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