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conmon.c
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#define _GNU_SOURCE
#include "utils.h"
#include "ctr_logging.h"
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <sys/prctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <sys/eventfd.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <unistd.h>
#include <inttypes.h>
#if __STDC_VERSION__ >= 199901L
/* C99 or later */
#else
#error conmon.c requires C99 or later
#endif
#include <glib.h>
#include <glib-unix.h>
#include "cmsg.h"
#include "config.h"
static volatile pid_t container_pid = -1;
static volatile pid_t create_pid = -1;
static gboolean opt_version = FALSE;
static gboolean opt_terminal = FALSE;
static gboolean opt_stdin = FALSE;
static gboolean opt_leave_stdin_open = FALSE;
static gboolean opt_syslog = FALSE;
static char *opt_cid = NULL;
static char *opt_cuuid = NULL;
static char *opt_name = NULL;
static char *opt_runtime_path = NULL;
static char *opt_bundle_path = NULL;
static char *opt_container_pid_file = NULL;
static char *opt_conmon_pid_file = NULL;
static gboolean opt_systemd_cgroup = FALSE;
static gboolean opt_no_pivot = FALSE;
static char *opt_exec_process_spec = NULL;
static gboolean opt_exec = FALSE;
static char *opt_restore_path = NULL;
static gchar **opt_restore_args = NULL;
static gchar **opt_runtime_args = NULL;
static gchar **opt_log_path = NULL;
static char *opt_exit_dir = NULL;
static int opt_timeout = 0;
static int64_t opt_log_size_max = -1;
static char *opt_socket_path = DEFAULT_SOCKET_PATH;
static gboolean opt_no_new_keyring = FALSE;
static char *opt_exit_command = NULL;
static gchar **opt_exit_args = NULL;
static gboolean opt_replace_listen_pid = FALSE;
static char *opt_log_level = NULL;
static GOptionEntry opt_entries[] = {
{"terminal", 't', 0, G_OPTION_ARG_NONE, &opt_terminal, "Terminal", NULL},
{"stdin", 'i', 0, G_OPTION_ARG_NONE, &opt_stdin, "Stdin", NULL},
{"leave-stdin-open", 0, 0, G_OPTION_ARG_NONE, &opt_leave_stdin_open, "Leave stdin open when attached client disconnects", NULL},
{"cid", 'c', 0, G_OPTION_ARG_STRING, &opt_cid, "Container ID", NULL},
{"cuuid", 'u', 0, G_OPTION_ARG_STRING, &opt_cuuid, "Container UUID", NULL},
{"name", 'n', 0, G_OPTION_ARG_STRING, &opt_name, "Container name", NULL},
{"runtime", 'r', 0, G_OPTION_ARG_STRING, &opt_runtime_path, "Runtime path", NULL},
{"restore", 0, 0, G_OPTION_ARG_STRING, &opt_restore_path, "Restore a container from a checkpoint", NULL},
{"restore-arg", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_restore_args,
"Additional arg to pass to the restore command. Can be specified multiple times", NULL},
{"runtime-arg", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_runtime_args,
"Additional arg to pass to the runtime. Can be specified multiple times", NULL},
{"no-new-keyring", 0, 0, G_OPTION_ARG_NONE, &opt_no_new_keyring, "Do not create a new session keyring for the container", NULL},
{"no-pivot", 0, 0, G_OPTION_ARG_NONE, &opt_no_pivot, "Do not use pivot_root", NULL},
{"replace-listen-pid", 0, 0, G_OPTION_ARG_NONE, &opt_replace_listen_pid, "Replace listen pid if set for oci-runtime pid", NULL},
{"bundle", 'b', 0, G_OPTION_ARG_STRING, &opt_bundle_path, "Bundle path", NULL},
{"pidfile", 0, 0, G_OPTION_ARG_STRING, &opt_container_pid_file, "PID file (DEPRECATED)", NULL},
{"container-pidfile", 'p', 0, G_OPTION_ARG_STRING, &opt_container_pid_file, "Container PID file", NULL},
{"conmon-pidfile", 'P', 0, G_OPTION_ARG_STRING, &opt_conmon_pid_file, "Conmon daemon PID file", NULL},
{"systemd-cgroup", 's', 0, G_OPTION_ARG_NONE, &opt_systemd_cgroup, "Enable systemd cgroup manager", NULL},
{"exec", 'e', 0, G_OPTION_ARG_NONE, &opt_exec, "Exec a command in a running container", NULL},
{"exec-process-spec", 0, 0, G_OPTION_ARG_STRING, &opt_exec_process_spec, "Path to the process spec for exec", NULL},
{"exit-dir", 0, 0, G_OPTION_ARG_STRING, &opt_exit_dir, "Path to the directory where exit files are written", NULL},
{"exit-command", 0, 0, G_OPTION_ARG_STRING, &opt_exit_command,
"Path to the program to execute when the container terminates its execution", NULL},
{"exit-command-arg", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_exit_args,
"Additional arg to pass to the exit command. Can be specified multiple times", NULL},
{"log-path", 'l', 0, G_OPTION_ARG_STRING_ARRAY, &opt_log_path, "Log file path", NULL},
{"timeout", 'T', 0, G_OPTION_ARG_INT, &opt_timeout, "Timeout in seconds", NULL},
{"log-size-max", 0, 0, G_OPTION_ARG_INT64, &opt_log_size_max, "Maximum size of log file", NULL},
{"socket-dir-path", 0, 0, G_OPTION_ARG_STRING, &opt_socket_path, "Location of container attach sockets", NULL},
{"version", 0, 0, G_OPTION_ARG_NONE, &opt_version, "Print the version and exit", NULL},
{"syslog", 0, 0, G_OPTION_ARG_NONE, &opt_syslog, "Log to syslog (use with cgroupfs cgroup manager)", NULL},
{"log-level", 0, 0, G_OPTION_ARG_STRING, &opt_log_level, "Print debug logs based on log level", NULL},
{NULL}};
#define CGROUP_ROOT "/sys/fs/cgroup"
#define OOM_SCORE "-999"
static ssize_t write_all(int fd, const void *buf, size_t count)
{
size_t remaining = count;
const char *p = buf;
ssize_t res;
while (remaining > 0) {
do {
res = write(fd, p, remaining);
} while (res == -1 && errno == EINTR);
if (res <= 0)
return -1;
remaining -= res;
p += res;
}
return count;
}
/*
* Returns the path for specified controller name for a pid.
* Returns NULL on error.
*/
static char *process_cgroup_subsystem_path(int pid, const char *subsystem)
{
_cleanup_free_ char *cgroups_file_path = g_strdup_printf("/proc/%d/cgroup", pid);
_cleanup_fclose_ FILE *fp = NULL;
fp = fopen(cgroups_file_path, "re");
if (fp == NULL) {
nwarnf("Failed to open cgroups file: %s", cgroups_file_path);
return NULL;
}
_cleanup_free_ char *line = NULL;
ssize_t read;
size_t len = 0;
char *ptr, *path;
char *subsystem_path = NULL;
int i;
while ((read = getline(&line, &len, fp)) != -1) {
_cleanup_strv_ char **subsystems = NULL;
ptr = strchr(line, ':');
if (ptr == NULL) {
nwarnf("Error parsing cgroup, ':' not found: %s", line);
return NULL;
}
ptr++;
path = strchr(ptr, ':');
if (path == NULL) {
nwarnf("Error parsing cgroup, second ':' not found: %s", line);
return NULL;
}
*path = 0;
path++;
subsystems = g_strsplit(ptr, ",", -1);
for (i = 0; subsystems[i] != NULL; i++) {
if (strcmp(subsystems[i], subsystem) == 0) {
char *subpath = strchr(subsystems[i], '=');
if (subpath == NULL) {
subpath = ptr;
} else {
*subpath = 0;
}
subsystem_path = g_strdup_printf("%s/%s%s", CGROUP_ROOT, subpath, path);
subsystem_path[strlen(subsystem_path) - 1] = '\0';
return subsystem_path;
}
}
}
return NULL;
}
static char *escape_json_string(const char *str)
{
GString *escaped;
const char *p;
p = str;
escaped = g_string_sized_new(strlen(str));
while (*p != 0) {
char c = *p++;
if (c == '\\' || c == '"') {
g_string_append_c(escaped, '\\');
g_string_append_c(escaped, c);
} else if (c == '\n') {
g_string_append_printf(escaped, "\\n");
} else if (c == '\t') {
g_string_append_printf(escaped, "\\t");
} else if ((c > 0 && c < 0x1f) || c == 0x7f) {
g_string_append_printf(escaped, "\\u00%02x", (guint)c);
} else {
g_string_append_c(escaped, c);
}
}
return g_string_free(escaped, FALSE);
}
static int get_pipe_fd_from_env(const char *envname)
{
char *pipe_str, *endptr;
int pipe_fd;
pipe_str = getenv(envname);
if (pipe_str == NULL)
return -1;
errno = 0;
pipe_fd = strtol(pipe_str, &endptr, 10);
if (errno != 0 || *endptr != '\0')
pexitf("unable to parse %s", envname);
if (fcntl(pipe_fd, F_SETFD, FD_CLOEXEC) == -1)
pexitf("unable to make %s CLOEXEC", envname);
return pipe_fd;
}
static void add_argv(GPtrArray *argv_array, ...) G_GNUC_NULL_TERMINATED;
static void add_argv(GPtrArray *argv_array, ...)
{
va_list args;
char *arg;
va_start(args, argv_array);
while ((arg = va_arg(args, char *)))
g_ptr_array_add(argv_array, arg);
va_end(args);
}
static void end_argv(GPtrArray *argv_array)
{
g_ptr_array_add(argv_array, NULL);
}
/* Global state */
static int runtime_status = -1;
static int container_status = -1;
static int masterfd_stdin = -1;
static int masterfd_stdout = -1;
static int masterfd_stderr = -1;
/* Used for attach */
struct conn_sock_s {
int fd;
gboolean readable;
gboolean writable;
};
GPtrArray *conn_socks = NULL;
static int oom_event_fd = -1;
static int attach_socket_fd = -1;
static int console_socket_fd = -1;
static int terminal_ctrl_fd = -1;
static gboolean timed_out = FALSE;
static GMainLoop *main_loop = NULL;
static void conn_sock_shutdown(struct conn_sock_s *sock, int how)
{
if (sock->fd == -1)
return;
shutdown(sock->fd, how);
switch (how) {
case SHUT_RD:
sock->readable = false;
break;
case SHUT_WR:
sock->writable = false;
break;
case SHUT_RDWR:
sock->readable = false;
sock->writable = false;
break;
}
if (!sock->writable && !sock->readable) {
close(sock->fd);
sock->fd = -1;
g_ptr_array_remove(conn_socks, sock);
}
}
static gboolean stdio_cb(int fd, GIOCondition condition, gpointer user_data);
static gboolean tty_hup_timeout_scheduled = false;
static gboolean tty_hup_timeout_cb(G_GNUC_UNUSED gpointer user_data)
{
tty_hup_timeout_scheduled = false;
g_unix_fd_add(masterfd_stdout, G_IO_IN, stdio_cb, GINT_TO_POINTER(STDOUT_PIPE));
return G_SOURCE_REMOVE;
}
static bool read_stdio(int fd, stdpipe_t pipe, gboolean *eof)
{
/* We use two extra bytes. One at the start, which we don't read into, instead
we use that for marking the pipe when we write to the attached socket.
One at the end to guarentee a null-terminated buffer for journald logging*/
char real_buf[STDIO_BUF_SIZE + 2];
char *buf = real_buf + 1;
ssize_t num_read = 0;
size_t i;
if (eof)
*eof = false;
num_read = read(fd, buf, STDIO_BUF_SIZE);
if (num_read == 0) {
if (eof)
*eof = true;
return false;
} else if (num_read < 0) {
nwarnf("stdio_input read failed %s", strerror(errno));
return false;
} else {
// Always null terminate the buffer, just in case.
buf[num_read] = '\0';
bool written = write_to_logs(pipe, buf, num_read);
if (!written)
return written;
if (conn_socks == NULL) {
return true;
}
real_buf[0] = pipe;
for (i = conn_socks->len; i > 0; i--) {
struct conn_sock_s *conn_sock = g_ptr_array_index(conn_socks, i - 1);
if (conn_sock->writable && write_all(conn_sock->fd, real_buf, num_read + 1) < 0) {
nwarn("Failed to write to socket");
conn_sock_shutdown(conn_sock, SHUT_WR);
}
}
return true;
}
}
static void on_sigchld(G_GNUC_UNUSED int signal)
{
raise(SIGUSR1);
}
static void on_sig_exit(int signal)
{
if (container_pid > 0) {
if (kill(container_pid, signal) == 0)
return;
} else if (create_pid > 0) {
if (kill(create_pid, signal) == 0)
return;
if (errno == ESRCH) {
/* The create_pid process might have exited, so try container_pid again. */
if (container_pid > 0 && kill(container_pid, signal) == 0)
return;
}
}
/* Just force a check if we get here. */
raise(SIGUSR1);
}
static void check_child_processes(GHashTable *pid_to_handler)
{
void (*cb)(GPid, int, gpointer);
for (;;) {
int status;
pid_t pid = waitpid(-1, &status, WNOHANG);
if (pid < 0 && errno == EINTR)
continue;
if (pid < 0 && errno == ECHILD) {
g_main_loop_quit(main_loop);
return;
}
if (pid < 0)
pexit("Failed to read child process status");
if (pid == 0)
return;
/* If we got here, pid > 0, so we have a valid pid to check. */
cb = g_hash_table_lookup(pid_to_handler, &pid);
if (cb)
cb(pid, status, 0);
}
}
static gboolean on_sigusr1_cb(gpointer user_data)
{
GHashTable *pid_to_handler = (GHashTable *)user_data;
check_child_processes(pid_to_handler);
return G_SOURCE_CONTINUE;
}
static gboolean stdio_cb(int fd, GIOCondition condition, gpointer user_data)
{
stdpipe_t pipe = GPOINTER_TO_INT(user_data);
gboolean read_eof = FALSE;
gboolean has_input = (condition & G_IO_IN) != 0;
gboolean has_hup = (condition & G_IO_HUP) != 0;
/* When we get here, condition can be G_IO_IN and/or G_IO_HUP.
IN means there is some data to read.
HUP means the other side closed the fd. In the case of a pine
this in final, and we will never get more data. However, in the
terminal case this just means that nobody has the terminal
open at this point, and this can be change whenever someone
opens the tty */
/* Read any data before handling hup */
if (has_input) {
read_stdio(fd, pipe, &read_eof);
}
if (has_hup && opt_terminal && pipe == STDOUT_PIPE) {
/* We got a HUP from the terminal master this means there
are no open slaves ptys atm, and we will get a lot
of wakeups until we have one, switch to polling
mode. */
/* If we read some data this cycle, wait one more, maybe there
is more in the buffer before we handle the hup */
if (has_input && !read_eof) {
return G_SOURCE_CONTINUE;
}
if (!tty_hup_timeout_scheduled) {
g_timeout_add(100, tty_hup_timeout_cb, NULL);
}
tty_hup_timeout_scheduled = true;
return G_SOURCE_REMOVE;
}
if (read_eof || (has_hup && !has_input)) {
/* End of input */
if (pipe == STDOUT_PIPE)
masterfd_stdout = -1;
if (pipe == STDERR_PIPE)
masterfd_stderr = -1;
close(fd);
return G_SOURCE_REMOVE;
}
return G_SOURCE_CONTINUE;
}
static gboolean timeout_cb(G_GNUC_UNUSED gpointer user_data)
{
timed_out = TRUE;
ninfo("Timed out, killing main loop");
g_main_loop_quit(main_loop);
return G_SOURCE_REMOVE;
}
static gboolean oom_cb(int fd, GIOCondition condition, G_GNUC_UNUSED gpointer user_data)
{
uint64_t oom_event;
ssize_t num_read = 0;
if ((condition & G_IO_IN) != 0) {
num_read = read(fd, &oom_event, sizeof(uint64_t));
if (num_read < 0) {
nwarn("Failed to read oom event from eventfd");
return G_SOURCE_CONTINUE;
}
if (num_read > 0) {
if (num_read != sizeof(uint64_t))
nwarn("Failed to read full oom event from eventfd");
ninfo("OOM received");
if (open("oom", O_CREAT, 0666) < 0) {
nwarn("Failed to write oom file");
}
return G_SOURCE_CONTINUE;
}
}
/* End of input */
close(fd);
oom_event_fd = -1;
return G_SOURCE_REMOVE;
}
#define CONN_SOCK_BUF_SIZE 32 * 1024 /* Match the write size in CopyDetachable */
static gboolean conn_sock_cb(int fd, GIOCondition condition, gpointer user_data)
{
char buf[CONN_SOCK_BUF_SIZE];
ssize_t num_read = 0;
struct conn_sock_s *sock = (struct conn_sock_s *)user_data;
if ((condition & G_IO_IN) != 0) {
num_read = read(fd, buf, CONN_SOCK_BUF_SIZE);
if (num_read < 0)
return G_SOURCE_CONTINUE;
if (num_read > 0 && masterfd_stdin >= 0) {
if (write_all(masterfd_stdin, buf, num_read) < 0) {
nwarn("Failed to write to container stdin");
}
return G_SOURCE_CONTINUE;
}
}
/* End of input */
conn_sock_shutdown(sock, SHUT_RD);
if (masterfd_stdin >= 0 && opt_stdin) {
if (!opt_leave_stdin_open) {
close(masterfd_stdin);
masterfd_stdin = -1;
} else {
ninfo("Not closing input");
}
}
return G_SOURCE_REMOVE;
}
static gboolean attach_cb(int fd, G_GNUC_UNUSED GIOCondition condition, G_GNUC_UNUSED gpointer user_data)
{
int conn_fd = accept(fd, NULL, NULL);
if (conn_fd == -1) {
if (errno != EWOULDBLOCK)
nwarn("Failed to accept client connection on attach socket");
} else {
struct conn_sock_s *conn_sock;
if (conn_socks == NULL) {
conn_socks = g_ptr_array_new_with_free_func(free);
}
conn_sock = malloc(sizeof(*conn_sock));
if (conn_sock == NULL) {
pexit("Failed to allocate memory");
}
conn_sock->fd = conn_fd;
conn_sock->readable = true;
conn_sock->writable = true;
g_unix_fd_add(conn_sock->fd, G_IO_IN | G_IO_HUP | G_IO_ERR, conn_sock_cb, conn_sock);
g_ptr_array_add(conn_socks, conn_sock);
ninfof("Accepted connection %d", conn_sock->fd);
}
return G_SOURCE_CONTINUE;
}
/*
* resize_winsz resizes the pty window size.
*/
static void resize_winsz(int height, int width)
{
struct winsize ws;
int ret;
ws.ws_row = height;
ws.ws_col = width;
ret = ioctl(masterfd_stdout, TIOCSWINSZ, &ws);
if (ret == -1) {
nwarn("Failed to set process pty terminal size");
}
}
#define CTLBUFSZ 200
static gboolean ctrl_cb(int fd, G_GNUC_UNUSED GIOCondition condition, G_GNUC_UNUSED gpointer user_data)
{
static char ctlbuf[CTLBUFSZ];
static int readsz = CTLBUFSZ - 1;
static char *readptr = ctlbuf;
ssize_t num_read = 0;
int ctl_msg_type = -1;
int height = -1;
int width = -1;
int ret;
num_read = read(fd, readptr, readsz);
if (num_read <= 0) {
nwarn("Failed to read from control fd");
return G_SOURCE_CONTINUE;
}
readptr[num_read] = '\0';
ninfof("Got ctl message: %s", ctlbuf);
char *beg = ctlbuf;
char *newline = strchrnul(beg, '\n');
/* Process each message which ends with a line */
while (*newline != '\0') {
ret = sscanf(ctlbuf, "%d %d %d\n", &ctl_msg_type, &height, &width);
if (ret != 3) {
nwarn("Failed to sscanf message");
return G_SOURCE_CONTINUE;
}
ninfof("Message type: %d, Height: %d, Width: %d", ctl_msg_type, height, width);
switch (ctl_msg_type) {
// This matches what we write from container_attach.go
case 1:
resize_winsz(height, width);
break;
case 2:
reopen_log_files();
break;
default:
ninfof("Unknown message type: %d", ctl_msg_type);
break;
}
beg = newline + 1;
newline = strchrnul(beg, '\n');
}
if (num_read == (CTLBUFSZ - 1) && beg == ctlbuf) {
/*
* We did not find a newline in the entire buffer.
* This shouldn't happen as our buffer is larger than
* the message that we expect to receive.
*/
nwarn("Could not find newline in entire buffer");
} else if (*beg == '\0') {
/* We exhausted all messages that were complete */
readptr = ctlbuf;
readsz = CTLBUFSZ - 1;
} else {
/*
* We copy remaining data to beginning of buffer
* and advance readptr after that.
*/
int cp_rem = 0;
do {
ctlbuf[cp_rem++] = *beg++;
} while (*beg != '\0');
readptr = ctlbuf + cp_rem;
readsz = CTLBUFSZ - 1 - cp_rem;
}
return G_SOURCE_CONTINUE;
}
static gboolean terminal_accept_cb(int fd, G_GNUC_UNUSED GIOCondition condition, G_GNUC_UNUSED gpointer user_data)
{
const char *csname = user_data;
struct file_t console;
int connfd = -1;
struct termios tset;
ninfof("about to accept from console_socket_fd: %d", fd);
connfd = accept4(fd, NULL, NULL, SOCK_CLOEXEC);
if (connfd < 0) {
nwarn("Failed to accept console-socket connection");
return G_SOURCE_CONTINUE;
}
/* Not accepting anything else. */
close(fd);
unlink(csname);
/* We exit if this fails. */
ninfof("about to recvfd from connfd: %d", connfd);
console = recvfd(connfd);
ninfof("console = {.name = '%s'; .fd = %d}", console.name, console.fd);
free(console.name);
/* We change the terminal settings to match kube settings */
if (tcgetattr(console.fd, &tset) == -1) {
nwarn("Failed to get console terminal settings");
goto exit;
}
tset.c_oflag |= ONLCR;
if (tcsetattr(console.fd, TCSANOW, &tset) == -1)
nwarn("Failed to set console terminal settings");
exit:
/* We only have a single fd for both pipes, so we just treat it as
* stdout. stderr is ignored. */
masterfd_stdin = console.fd;
masterfd_stdout = console.fd;
/* Clean up everything */
close(connfd);
return G_SOURCE_CONTINUE;
}
static int get_exit_status(int status)
{
if (WIFEXITED(status))
return WEXITSTATUS(status);
if (WIFSIGNALED(status))
return 128 + WTERMSIG(status);
return -1;
}
static void runtime_exit_cb(G_GNUC_UNUSED GPid pid, int status, G_GNUC_UNUSED gpointer user_data)
{
runtime_status = status;
create_pid = -1;
g_main_loop_quit(main_loop);
}
static void container_exit_cb(G_GNUC_UNUSED GPid pid, int status, G_GNUC_UNUSED gpointer user_data)
{
if (get_exit_status(status) != 0) {
ninfof("container %d exited with status %d", pid, get_exit_status(status));
}
container_status = status;
container_pid = -1;
g_main_loop_quit(main_loop);
}
static void write_sync_fd(int sync_pipe_fd, int res, const char *message)
{
_cleanup_free_ char *escaped_message = NULL;
_cleanup_free_ char *json = NULL;
const char *res_key;
ssize_t len;
if (sync_pipe_fd == -1)
return;
if (opt_exec)
res_key = "exit_code";
else
res_key = "pid";
if (message) {
escaped_message = escape_json_string(message);
json = g_strdup_printf("{\"%s\": %d, \"message\": \"%s\"}\n", res_key, res, escaped_message);
} else {
json = g_strdup_printf("{\"%s\": %d}\n", res_key, res);
}
len = strlen(json);
if (write_all(sync_pipe_fd, json, len) != len) {
pexit("Unable to send container stderr message to parent");
}
}
static char *setup_console_socket(void)
{
struct sockaddr_un addr = {0};
_cleanup_free_ const char *tmpdir = g_get_tmp_dir();
_cleanup_free_ char *csname = g_build_filename(tmpdir, "conmon-term.XXXXXX", NULL);
/*
* Generate a temporary name. Is this unsafe? Probably, but we can
* replace it with a rename(2) setup if necessary.
*/
int unusedfd = g_mkstemp(csname);
if (unusedfd < 0)
pexit("Failed to generate random path for console-socket");
close(unusedfd);
addr.sun_family = AF_UNIX;
strncpy(addr.sun_path, csname, sizeof(addr.sun_path) - 1);
ninfof("addr{sun_family=AF_UNIX, sun_path=%s}", addr.sun_path);
/* Bind to the console socket path. */
console_socket_fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (console_socket_fd < 0)
pexit("Failed to create console-socket");
if (fchmod(console_socket_fd, 0700))
pexit("Failed to change console-socket permissions");
/* XXX: This should be handled with a rename(2). */
if (unlink(csname) < 0)
pexit("Failed to unlink temporary random path");
if (bind(console_socket_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0)
pexit("Failed to bind to console-socket");
if (listen(console_socket_fd, 128) < 0)
pexit("Failed to listen on console-socket");
return g_strdup(csname);
}
static char *setup_attach_socket(void)
{
_cleanup_free_ char *attach_sock_path = NULL;
char *attach_symlink_dir_path;
struct sockaddr_un attach_addr = {0};
attach_addr.sun_family = AF_UNIX;
/*
* Create a symlink so we don't exceed unix domain socket
* path length limit.
*/
attach_symlink_dir_path = g_build_filename(opt_socket_path, opt_cuuid, NULL);
if (unlink(attach_symlink_dir_path) == -1 && errno != ENOENT)
pexit("Failed to remove existing symlink for attach socket directory");
/*
* This is to address a corner case where the symlink path length can end up to be
* the same as the socket. When it happens, the symlink prevents the socket to be
* be created. This could still be a problem with other containers, but it is safe
* to assume the CUUIDs don't change length in the same directory. As a workaround,
* in such case, make the symlink one char shorter.
*/
if (strlen(attach_symlink_dir_path) == (sizeof(attach_addr.sun_path) - 1))
attach_symlink_dir_path[sizeof(attach_addr.sun_path) - 2] = '\0';
if (symlink(opt_bundle_path, attach_symlink_dir_path) == -1)
pexit("Failed to create symlink for attach socket");
attach_sock_path = g_build_filename(opt_socket_path, opt_cuuid, "attach", NULL);
ninfof("attach sock path: %s", attach_sock_path);
strncpy(attach_addr.sun_path, attach_sock_path, sizeof(attach_addr.sun_path) - 1);
ninfof("addr{sun_family=AF_UNIX, sun_path=%s}", attach_addr.sun_path);
/*
* We make the socket non-blocking to avoid a race where client aborts connection
* before the server gets a chance to call accept. In that scenario, the server
* accept blocks till a new client connection comes in.
*/
attach_socket_fd = socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
if (attach_socket_fd == -1)
pexit("Failed to create attach socket");
if (fchmod(attach_socket_fd, 0700))
pexit("Failed to change attach socket permissions");
if (bind(attach_socket_fd, (struct sockaddr *)&attach_addr, sizeof(struct sockaddr_un)) == -1)
pexitf("Failed to bind attach socket: %s", attach_sock_path);
if (listen(attach_socket_fd, 10) == -1)
pexitf("Failed to listen on attach socket: %s", attach_sock_path);
g_unix_fd_add(attach_socket_fd, G_IO_IN, attach_cb, NULL);
return attach_symlink_dir_path;
}
static void setup_terminal_control_fifo()
{
_cleanup_free_ char *ctl_fifo_path = g_build_filename(opt_bundle_path, "ctl", NULL);
ninfof("ctl fifo path: %s", ctl_fifo_path);
/* Setup fifo for reading in terminal resize and other stdio control messages */
if (mkfifo(ctl_fifo_path, 0666) == -1)
pexitf("Failed to mkfifo at %s", ctl_fifo_path);
terminal_ctrl_fd = open(ctl_fifo_path, O_RDONLY | O_NONBLOCK | O_CLOEXEC);
if (terminal_ctrl_fd == -1)
pexit("Failed to open control fifo");
/*
* Open a dummy writer to prevent getting flood of POLLHUPs when
* last writer closes.
*/
int dummyfd = open(ctl_fifo_path, O_WRONLY | O_CLOEXEC);
if (dummyfd == -1)
pexit("Failed to open dummy writer for fifo");
g_unix_fd_add(terminal_ctrl_fd, G_IO_IN, ctrl_cb, NULL);
ninfof("terminal_ctrl_fd: %d", terminal_ctrl_fd);
}
static void setup_oom_handling(int container_pid)
{
/* Setup OOM notification for container process */
_cleanup_free_ char *memory_cgroup_path = process_cgroup_subsystem_path(container_pid, "memory");
_cleanup_close_ int cfd = -1;
int ofd = -1; /* Not closed */
if (!memory_cgroup_path) {
nexit("Failed to get memory cgroup path");
}
_cleanup_free_ char *memory_cgroup_file_path = g_build_filename(memory_cgroup_path, "cgroup.event_control", NULL);
if ((cfd = open(memory_cgroup_file_path, O_WRONLY | O_CLOEXEC)) == -1) {
nwarnf("Failed to open %s", memory_cgroup_file_path);
return;
}
_cleanup_free_ char *memory_cgroup_file_oom_path = g_build_filename(memory_cgroup_path, "memory.oom_control", NULL);
if ((ofd = open(memory_cgroup_file_oom_path, O_RDONLY | O_CLOEXEC)) == -1)
pexitf("Failed to open %s", memory_cgroup_file_oom_path);
if ((oom_event_fd = eventfd(0, EFD_CLOEXEC)) == -1)
pexit("Failed to create eventfd");
_cleanup_free_ char *data = g_strdup_printf("%d %d", oom_event_fd, ofd);
if (write_all(cfd, data, strlen(data)) < 0)
pexit("Failed to write to cgroup.event_control");
g_unix_fd_add(oom_event_fd, G_IO_IN, oom_cb, NULL);
}
static void do_exit_command()
{
gchar **args;
size_t n_args = 0;
/* Count the additional args, if any. */
if (opt_exit_args)
for (; opt_exit_args[n_args]; n_args++)
;
args = malloc(sizeof(gchar *) * (n_args + 2));
if (args == NULL)
_exit(EXIT_FAILURE);
args[0] = opt_exit_command;
if (opt_exit_args)
for (n_args = 0; opt_exit_args[n_args]; n_args++)
args[n_args + 1] = opt_exit_args[n_args];
args[n_args + 1] = NULL;
execv(opt_exit_command, args);
/* Should not happen, but better be safe. */
_exit(EXIT_FAILURE);
}
int main(int argc, char *argv[])
{
int fd, ret;
char cwd[PATH_MAX];
_cleanup_free_ char *default_pid_file = NULL;
_cleanup_free_ char *csname = NULL;
GError *err = NULL;
_cleanup_free_ char *contents = NULL;
pid_t main_pid;
/* Used for !terminal cases. */
int slavefd_stdin = -1;
int slavefd_stdout = -1;
int slavefd_stderr = -1;
char buf[BUF_SIZE];
int num_read;
int sync_pipe_fd = -1;
int start_pipe_fd = -1;
GError *error = NULL;
GOptionContext *context;
GPtrArray *runtime_argv = NULL;
_cleanup_close_ int dev_null_r = -1;
_cleanup_close_ int dev_null_w = -1;
int fds[2];
int oom_score_fd = -1;
/* Command line parameters */
context = g_option_context_new("- conmon utility");
g_option_context_add_main_entries(context, opt_entries, "conmon");
if (!g_option_context_parse(context, &argc, &argv, &error)) {
g_print("option parsing failed: %s\n", error->message);
exit(1);
}
if (opt_version) {
g_print("conmon version " VERSION "\ncommit: " GIT_COMMIT "\n");
exit(0);
}
if (opt_cid == NULL) {
fprintf(stderr, "Container ID not provided. Use --cid\n");
exit(EXIT_FAILURE);
}
set_conmon_logs(opt_log_level, opt_cid, opt_syslog);
oom_score_fd = open("/proc/self/oom_score_adj", O_WRONLY);
if (oom_score_fd < 0) {
ndebugf("failed to open /proc/self/oom_score_adj: %s\n", strerror(errno));
} else {
if (write(oom_score_fd, OOM_SCORE, strlen(OOM_SCORE)) < 0) {
ndebugf("failed to write to /proc/self/oom_score_adj: %s\n", strerror(errno));
}
close(oom_score_fd);
}
main_loop = g_main_loop_new(NULL, FALSE);
if (opt_restore_path && opt_exec)
nexit("Cannot use 'exec' and 'restore' at the same time.");
if (!opt_exec && opt_cuuid == NULL)
nexit("Container UUID not provided. Use --cuuid");
if (opt_name == NULL)
nexit("Container name not provided. Use --name");
if (opt_runtime_path == NULL)