267 lines
6.8 KiB
C
267 lines
6.8 KiB
C
#define _GNU_SOURCE
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/epoll.h>
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#include <sys/prctl.h>
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#include <sys/wait.h>
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#include <termios.h>
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#include <unistd.h>
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#include <glib.h>
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#define pexit(fmt, ...) \
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do { \
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fprintf(stderr, "conmon: " fmt " %m\n", ##__VA_ARGS__); \
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exit(EXIT_FAILURE); \
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} while (0)
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#define nexit(fmt, ...) \
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do { \
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fprintf(stderr, "conmon: " fmt "\n", ##__VA_ARGS__); \
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exit(EXIT_FAILURE); \
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} while (0)
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#define nwarn(fmt, ...) \
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do { \
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fprintf(stderr, "conmon: " fmt "\n", ##__VA_ARGS__); \
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} while (0)
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#define _cleanup_(x) __attribute__((cleanup(x)))
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static inline void freep(void *p) { free(*(void **)p); }
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static inline void closep(int *fd) {
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if (*fd >= 0)
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close(*fd);
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*fd = -1;
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}
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#define _cleanup_free_ _cleanup_(freep)
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#define _cleanup_close_ _cleanup_(closep)
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struct termios tty_orig;
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static void tty_restore(void)
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{
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if (tcsetattr(STDIN_FILENO, TCSANOW, &tty_orig) == -1)
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pexit("tcsetattr");
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}
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#define BUF_SIZE 256
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#define CMD_SIZE 1024
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#define MAX_EVENTS 10
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int main(int argc, char *argv[])
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{
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int ret;
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int opt;
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bool terminal = FALSE;
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const char *cid = NULL;
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char cmd[CMD_SIZE];
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GError *err = NULL;
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_cleanup_free_ char *contents;
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int cpid = -1;
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int status;
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pid_t pid;
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_cleanup_close_ int mfd = -1;
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_cleanup_close_ int epfd = -1;
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char slname[BUF_SIZE];
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char buf[BUF_SIZE];
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int num_read;
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struct termios t;
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struct epoll_event ev;
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struct epoll_event evlist[MAX_EVENTS];
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int child_pipe = -1;
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char *sync_pipe, *endptr;
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int len;
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while ((opt = getopt(argc, argv, "tc:")) != -1) {
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switch(opt) {
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case 't':
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terminal = TRUE;
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break;
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case 'c':
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cid = optarg;
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break;
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case '?':
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if (optopt == 'c')
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nexit("Option -%c requires an argument.", optopt);
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else if (isprint (optopt))
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nexit("Unknown option `-%c'.", optopt);
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else
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nexit("Unknown option character `\\x%x'.\n", optopt);
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default:
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nexit("Usage: %s [-c container_id] [-t]", argv[0]);
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}
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}
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if (cid == NULL) {
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nexit("Container ID not passed");
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}
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sync_pipe = getenv("_OCI_SYNCPIPE");
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if (sync_pipe) {
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errno = 0;
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child_pipe = strtol(sync_pipe, &endptr, 10);
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if (errno != 0 || *endptr != '\0')
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pexit("unable to parse _OCI_SYNCPIPE");
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}
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/*
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* Set self as subreaper so we can wait for container process
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* and return its exit code.
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*/
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ret = prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0);
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if (ret != 0) {
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pexit("Failed to set as subreaper");
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}
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if (terminal) {
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/* Open the master pty */
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mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
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if (mfd < 0)
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pexit("Failed to open console master pty");
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/* Grant access to the slave pty */
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if (grantpt(mfd) == -1)
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pexit("Failed to grant access to slave pty");
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/* Unlock the slave pty */
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if (unlockpt(mfd) == -1) { /* Unlock slave pty */
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pexit("Failed to unlock the slave pty");
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}
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/* Get the slave pty name */
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ret = ptsname_r(mfd, slname, BUF_SIZE);
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if (ret != 0) {
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pexit("Failed to get the slave pty name");
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}
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}
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/* Create the container */
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if (terminal) {
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snprintf(cmd, CMD_SIZE, "runc create %s --pid-file pidfile --console %s", cid, slname);
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} else {
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snprintf(cmd, CMD_SIZE, "runc create %s --pid-file pidfile", cid);
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}
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ret = system(cmd);
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if (ret != 0) {
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nexit("Failed to create container");
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}
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/* Read the pid so we can wait for the process to exit */
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g_file_get_contents("pidfile", &contents, NULL, &err);
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if (err) {
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fprintf(stderr, "Failed to read pidfile: %s\n", err->message);
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g_error_free(err);
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exit(1);
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}
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cpid = atoi(contents);
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printf("container PID: %d\n", cpid);
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/* Send the container pid back to parent */
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if (child_pipe > 0) {
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len = snprintf(buf, BUF_SIZE, "{\"pid\": %d}\n", cpid);
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if (len < 0 || write(child_pipe, buf, len) != len) {
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pexit("unable to send container pid to parent");
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}
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}
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if (terminal) {
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/* Save exiting termios settings */
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if (tcgetattr(STDIN_FILENO, &tty_orig) == -1)
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pexit("tcegetattr");
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/* Settings for raw mode */
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t.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL | IEXTEN);
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t.c_iflag &= ~(BRKINT | ICRNL | IGNBRK | IGNCR | INLCR | INPCK |
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ISTRIP | IXON | IXOFF | IGNPAR | PARMRK);
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t.c_oflag &= ~OPOST;
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t.c_cc[VMIN] = 1;
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t.c_cc[VTIME] = 0;
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/* Set terminal to raw mode */
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t) == -1)
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pexit("tcsetattr");
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/* Setup terminal restore on exit */
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if (atexit(tty_restore) != 0)
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pexit("atexit");
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epfd = epoll_create(5);
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if (epfd < 0)
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pexit("epoll_create");
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ev.events = EPOLLIN;
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ev.data.fd = STDIN_FILENO;
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if (epoll_ctl(epfd, EPOLL_CTL_ADD, STDIN_FILENO, &ev) < 0) {
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pexit("Failed to add stdin to epoll");
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}
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ev.data.fd = mfd;
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if (epoll_ctl(epfd, EPOLL_CTL_ADD, mfd, &ev) < 0) {
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pexit("Failed to add console master fd to epoll");
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}
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/* Copy data back and forth between STDIN and master fd */
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while (true) {
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int ready = epoll_wait(epfd, evlist, MAX_EVENTS, -1);
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for (int i = 0; i < ready; i++) {
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if (evlist[i].events & EPOLLIN) {
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if (evlist[i].data.fd == STDIN_FILENO) {
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num_read = read(STDIN_FILENO, buf, BUF_SIZE);
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if (num_read <= 0)
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goto out;
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if (write(mfd, buf, num_read) != num_read) {
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nwarn("partial/failed write (masterFd)");
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goto out;
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}
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} else if (evlist[i].data.fd == mfd) {
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num_read = read(mfd, buf, BUF_SIZE);
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if (num_read <= 0)
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goto out;
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if (write(STDOUT_FILENO, buf, num_read) != num_read) {
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nwarn("partial/failed write (STDOUT_FILENO)");
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goto out;
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}
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}
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} else if (evlist[i].events & (EPOLLHUP | EPOLLERR)) {
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printf("closing fd %d\n", evlist[i].data.fd);
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if (close(evlist[i].data.fd) < 0)
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pexit("close");
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goto out;
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}
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}
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}
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out:
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tty_restore();
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}
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/* Wait for the container process and record its exit code */
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while ((pid = waitpid(-1, &status, 0)) > 0) {
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printf("PID %d exited\n", pid);
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if (pid == cpid) {
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_cleanup_free_ char *status_str = NULL;
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ret = asprintf(&status_str, "%d", status);
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if (ret < 0) {
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pexit("Failed to allocate memory for status");
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}
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g_file_set_contents("exit", status_str, strlen(status_str), &err);
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if (err) {
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fprintf(stderr, "Failed to write %s to exit file: %s\n", status_str, err->message);
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g_error_free(err);
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exit(1);
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}
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break;
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}
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}
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return EXIT_SUCCESS;
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}
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