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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/socket.h>
#include <signal.h>
#include <poll.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdbool.h>
#include <logwrap/logwrap.h>
#include "private/android_filesystem_config.h"
#include "cutils/log.h"
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
static int signal_fd_write;
#define ERROR(fmt, args...) \
do { \
fprintf(stderr, fmt, ## args); \
ALOG(LOG_ERROR, "logwrapper", fmt, ## args); \
} while(0)
#define FATAL_CHILD(fmt, args...) \
do { \
ERROR(fmt, ## args); \
_exit(-1); \
} while(0)
static int parent(const char *tag, int parent_read, int signal_fd, pid_t pid,
int *chld_sts, bool logwrap) {
int status = 0;
char buffer[4096];
struct pollfd poll_fds[] = {
[0] = {
.fd = signal_fd,
.events = POLLIN,
},
[1] = {
.fd = parent_read,
.events = POLLIN,
},
};
int rc = 0;
sigset_t chldset;
int a = 0; // start index of unprocessed data
int b = 0; // end index of unprocessed data
int sz;
bool remote_hung = false;
bool found_child = false;
char *btag = basename(tag);
if (!btag) btag = (char*) tag;
sigemptyset(&chldset);
sigaddset(&chldset, SIGCHLD);
pthread_sigmask(SIG_UNBLOCK, &chldset, NULL);
while (!found_child) {
if (poll(poll_fds, remote_hung ? 1 : 2, -1) < 0) {
if (errno == EINTR)
continue;
ERROR("poll failed\n");
rc = -1;
goto err_poll;
}
if (!remote_hung) {
if (poll_fds[1].revents & POLLIN) {
sz = read(parent_read, &buffer[b], sizeof(buffer) - 1 - b);
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';
if (logwrap)
ALOG(LOG_INFO, btag, "%s", &buffer[a]);
a = b + 1;
}
}
if (a == 0 && b == sizeof(buffer) - 1) {
// buffer is full, flush
buffer[b] = '\0';
if (logwrap)
ALOG(LOG_INFO, btag, "%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;
}
}
if (poll_fds[1].revents & POLLHUP) {
remote_hung = true;
}
}
if (poll_fds[0].revents & POLLIN) {
char tmp[32];
int ret;
read(signal_fd, tmp, sizeof(tmp));
while (!found_child) {
do {
ret = waitpid(-1, &status, WNOHANG);
} while (ret < 0 && errno == EINTR);
if (ret <= 0)
break;
found_child = (pid == ret);
}
}
}
// Flush remaining data
if (a != b) {
buffer[b] = '\0';
if (logwrap)
ALOG(LOG_INFO, btag, "%s", &buffer[a]);
}
if (WIFEXITED(status)) {
if (WEXITSTATUS(status))
ALOG(LOG_INFO, "logwrapper", "%s terminated by exit(%d)", btag,
WEXITSTATUS(status));
if (chld_sts == NULL)
rc = WEXITSTATUS(status);
} else {
if (chld_sts == NULL)
rc = -ECHILD;
if (WIFSIGNALED(status))
ALOG(LOG_INFO, "logwrapper", "%s terminated by signal %d", btag,
WTERMSIG(status));
else if (WIFSTOPPED(status))
ALOG(LOG_INFO, "logwrapper", "%s stopped by signal %d", btag,
WSTOPSIG(status));
}
if (chld_sts != NULL)
*chld_sts = status;
err_poll:
return rc;
}
static void child(int argc, char* argv[], bool logwrap) {
// 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)) {
FATAL_CHILD("executing %s failed: %s\n", argv_child[0],
strerror(errno));
}
}
static void sigchld_handler(int sig) {
write(signal_fd_write, &sig, 1);
}
int android_fork_execvp(int argc, char* argv[], int *status, bool ignore_int_quit,
bool logwrap) {
pid_t pid;
int parent_ptty;
int child_ptty;
char *child_devname = NULL;
struct sigaction chldact;
struct sigaction oldchldact;
struct sigaction intact;
struct sigaction quitact;
sigset_t blockset;
sigset_t oldset;
int sockets[2];
int rc = 0;
/* Use ptty instead of socketpair so that STDOUT is not buffered */
parent_ptty = open("/dev/ptmx", O_RDWR);
if (parent_ptty < 0) {
ERROR("Cannot create parent ptty\n");
rc = -1;
goto err_open;
}
if (grantpt(parent_ptty) || unlockpt(parent_ptty) ||
((child_devname = (char*)ptsname(parent_ptty)) == 0)) {
ERROR("Problem with /dev/ptmx\n");
rc = -1;
goto err_ptty;
}
sigemptyset(&blockset);
sigaddset(&blockset, SIGINT);
sigaddset(&blockset, SIGQUIT);
sigaddset(&blockset, SIGCHLD);
pthread_sigmask(SIG_BLOCK, &blockset, &oldset);
pid = fork();
if (pid < 0) {
ERROR("Failed to fork\n");
rc = -1;
goto err_fork;
} else if (pid == 0) {
pthread_sigmask(SIG_SETMASK, &oldset, NULL);
close(parent_ptty);
child_ptty = open(child_devname, O_RDWR);
if (child_ptty < 0) {
FATAL_CHILD("Problem with child ptty\n");
return -1;
}
// redirect stdout and stderr
dup2(child_ptty, 1);
dup2(child_ptty, 2);
close(child_ptty);
child(argc, argv, logwrap);
} else {
struct sigaction ignact;
memset(&chldact, 0, sizeof(chldact));
chldact.sa_handler = sigchld_handler;
chldact.sa_flags = SA_NOCLDSTOP;
sigaction(SIGCHLD, &chldact, &oldchldact);
if ((!(oldchldact.sa_flags & SA_SIGINFO) &&
oldchldact.sa_handler != SIG_DFL &&
oldchldact.sa_handler != SIG_IGN) ||
((oldchldact.sa_flags & SA_SIGINFO) &&
oldchldact.sa_sigaction != NULL)) {
ALOG(LOG_WARN, "logwrapper", "logwrap replaced the SIGCHLD "
"handler and might cause interaction issues");
}
if (ignore_int_quit) {
memset(&ignact, 0, sizeof(ignact));
ignact.sa_handler = SIG_IGN;
sigaction(SIGINT, &ignact, &intact);
sigaction(SIGQUIT, &ignact, &quitact);
}
rc = socketpair(AF_UNIX, SOCK_STREAM, 0, sockets);
if (rc == -1) {
ERROR("socketpair failed: %s\n", strerror(errno));
goto err_socketpair;
}
fcntl(sockets[0], F_SETFD, FD_CLOEXEC);
fcntl(sockets[0], F_SETFL, O_NONBLOCK);
fcntl(sockets[1], F_SETFD, FD_CLOEXEC);
fcntl(sockets[1], F_SETFL, O_NONBLOCK);
signal_fd_write = sockets[0];
rc = parent(argv[0], parent_ptty, sockets[1], pid, status, logwrap);
}
close(sockets[0]);
close(sockets[1]);
err_socketpair:
if (ignore_int_quit) {
sigaction(SIGINT, &intact, NULL);
sigaction(SIGQUIT, &quitact, NULL);
}
sigaction(SIGCHLD, &oldchldact, NULL);
err_fork:
pthread_sigmask(SIG_SETMASK, &oldset, NULL);
err_ptty:
close(parent_ptty);
err_open:
return rc;
}
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