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Add support for console handling

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Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
This commit is contained in:
Mrunal Patel 2016-09-02 14:33:54 -07:00
parent 4cf737bb7d
commit bce17e63f6
1 changed files with 147 additions and 26 deletions
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173
conmon/conmon.c
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@ -1,81 +1,202 @@
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <errno.h>
#include <termios.h>
#include <unistd.h>
#include <glib.h>
#define pexit(fmt, ...) \
do { \
fprintf(stderr, "conmon: " fmt " %m\n", ##__VA_ARGS__); \
exit(EXIT_FAILURE); \
} while (0)
#define pexit(fmt, ...) \
do { \
fprintf(stderr, "conmon: " fmt " %m\n", ##__VA_ARGS__); \
exit(EXIT_FAILURE); \
} while (0)
#define nexit(fmt, ...) \
do { \
fprintf(stderr, "conmon: " fmt "\n", ##__VA_ARGS__); \
exit(EXIT_FAILURE); \
} while (0)
#define nexit(fmt, ...) \
do { \
fprintf(stderr, "conmon: " fmt "\n", ##__VA_ARGS__); \
exit(EXIT_FAILURE); \
} while (0)
#define nexit(fmt, ...) \
do { \
fprintf(stderr, "conmon: " fmt "\n", ##__VA_ARGS__); \
exit(EXIT_FAILURE); \
} while (0)
#define nwarn(fmt, ...) \
do { \
fprintf(stderr, "conmon: " fmt "\n", ##__VA_ARGS__); \
} while (0)
#define _cleanup_(x) __attribute__((cleanup(x)))
static inline void freep(void *p) {
free(*(void**) p);
static inline void freep(void *p) { free(*(void **)p); }
static inline void closep(int *fd) {
if (*fd >= 0)
close(*fd);
*fd = -1;
}
#define _cleanup_free_ _cleanup_(freep)
#define _cleanup_close_ _cleanup_(closep)
struct termios tty_orig;
static void tty_restore(void)
{
if (tcsetattr(STDIN_FILENO, TCSANOW, &tty_orig) == -1)
pexit("tcsetattr");
}
#define BUF_SIZE 256
#define CMD_SIZE 1024
#define MAX_EVENTS 10
int main(int argc, char *argv[])
{
int ret;
const char *cid;
char cmd[128];
char cmd[CMD_SIZE];
GError *err = NULL;
gchar *contents;
_cleanup_free_ char *contents;
int cpid = -1;
int status;
pid_t pid;
_cleanup_close_ int mfd = -1;
_cleanup_close_ int epfd = -1;
char slname[BUF_SIZE];
char buf[BUF_SIZE];
int num_read;
struct termios t;
struct epoll_event ev;
struct epoll_event evlist[MAX_EVENTS];
if (argc < 2) {
nexit("Run as: conmon <id>");
}
// Get the container id
/* Get the container id */
cid = argv[1];
// Set self as subreaper so we can wait for container process
// and return its exit code.
/*
* Set self as subreaper so we can wait for container process
* and return its exit code.
*/
ret = prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0);
if (ret != 0) {
pexit("Failed to set as subreaper");
}
snprintf(cmd, 128, "runc create %s --pid-file pidfile", cid);
/* Open the master pty */
mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
if (mfd < 0)
pexit("Failed to open console master pty");
/* Grant access to the slave pty */
if (grantpt(mfd) == -1)
pexit("Failed to grant access to slave pty");
/* Unlock the slave pty */
if (unlockpt(mfd) == -1) { /* Unlock slave pty */
pexit("Failed to unlock the slave pty");
}
/* Get the slave pty name */
ret = ptsname_r(mfd, slname, BUF_SIZE);
if (ret != 0) {
pexit("Failed to get the slave pty name");
}
/* Create the container */
snprintf(cmd, CMD_SIZE, "runc create %s --pid-file pidfile --console %s", cid, slname);
ret = system(cmd);
if (ret != 0) {
nexit("Failed to create container");
}
// Read the pid so we can wait for the process to exit
/* Read the pid so we can wait for the process to exit */
g_file_get_contents("pidfile", &contents, NULL, &err);
if (err) {
fprintf(stderr, "Failed to read pidfile: %s\n", err->message);
g_error_free(err);
exit(1);
}
}
cpid = atoi(contents);
printf("container PID: %d\n", cpid);
/* Save exiting termios settings */
if (tcgetattr(STDIN_FILENO, &tty_orig) == -1)
pexit("tcegetattr");
/* Settings for raw mode */
t.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL | IEXTEN);
t.c_iflag &= ~(BRKINT | ICRNL | IGNBRK | IGNCR | INLCR | INPCK |
ISTRIP | IXON | IXOFF | IGNPAR | PARMRK);
t.c_oflag &= ~OPOST;
t.c_cc[VMIN] = 1;
t.c_cc[VTIME] = 0;
/* Set terminal to raw mode */
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t) == -1)
pexit("tcsetattr");
/* Setup terminal restore on exit */
if (atexit(tty_restore) != 0)
pexit("atexit");
epfd = epoll_create(5);
if (epfd < 0)
pexit("epoll_create");
ev.events = EPOLLIN;
ev.data.fd = STDIN_FILENO;
if (epoll_ctl(epfd, EPOLL_CTL_ADD, STDIN_FILENO, &ev) < 0) {
pexit("Failed to add stdin to epoll");
}
ev.data.fd = mfd;
if (epoll_ctl(epfd, EPOLL_CTL_ADD, mfd, &ev) < 0) {
pexit("Failed to add console master fd to epoll");
}
/* Copy data back and forth between STDIN and master fd */
while (true) {
int ready = epoll_wait(epfd, evlist, MAX_EVENTS, -1);
for (int i = 0; i < ready; i++) {
if (evlist[i].events & EPOLLIN) {
if (evlist[i].data.fd == STDIN_FILENO) {
num_read = read(STDIN_FILENO, buf, BUF_SIZE);
if (num_read <= 0)
goto out;
if (write(mfd, buf, num_read) != num_read) {
nwarn("partial/failed write (masterFd)");
goto out;
}
} else if (evlist[i].data.fd == mfd) {
num_read = read(mfd, buf, BUF_SIZE);
if (num_read <= 0)
goto out;
if (write(STDOUT_FILENO, buf, num_read) != num_read) {
nwarn("partial/failed write (STDOUT_FILENO)");
goto out;
}
}
} else if (evlist[i].events & (EPOLLHUP | EPOLLERR)) {
printf("closing fd %d\n", evlist[i].data.fd);
if (close(evlist[i].data.fd) < 0)
pexit("close");
goto out;
}
}
}
out:
tty_restore();
/* Wait for the container process and record its exit code */
while ((pid = waitpid(-1, &status, 0)) > 0) {
printf("PID %d exited\n", pid);
if (pid == cpid) {