Based on Serge Hallyn's patch:
"Trivial patch, and I'm not sure whether we want this or want to do
it this way. But it saves me having to do it during my restart.sh
wrapper shell-script."
Make sure that the old /dev/pts is un-mounted prior to the mount of
the new one.
Signed-off-by: Oren Laadan <orenl@xxxxxxxxxxxxxxx>
---
restart.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 files changed, 40 insertions(+), 0 deletions(-)
diff --git a/restart.c b/restart.c
index f42b456..e3c4a5c 100644
--- a/restart.c
+++ b/restart.c
@@ -53,6 +53,7 @@ static char usage_str[] =
" --signal=SIG send SIG to root task on SIGINT (default: SIGKILL\n"
" to container root, SIGINT otherwise)\n"
" --mntns restart under a private mounts namespace\n"
+" --mount-pty start in a new devpts namespace to supprt ptys\n"
" -w,--wait wait for root task to termiate (default)\n"
" --show-status show exit status of root task (implies -w)\n"
" --copy-status imitate exit status of root task (implies -w)\n"
@@ -275,6 +276,7 @@ int global_send_sigint = -1;
int global_sent_sigint;
static int ckpt_remount_proc(void);
+static int ckpt_remount_devpts(void);
static int ckpt_build_tree(struct ckpt_ctx *ctx);
static int ckpt_init_tree(struct ckpt_ctx *ctx);
@@ -342,6 +344,7 @@ struct args {
char *root;
int wait;
int mntns;
+ int mnt_pty;
int show_status;
int copy_status;
char *freezer;
@@ -432,6 +435,7 @@ static void parse_args(struct args *args, int argc, char *argv[])
{ "debug", no_argument, NULL, 'd' },
{ "warn-pidzero", no_argument, NULL, 9 },
{ "fail-pidzero", no_argument, NULL, 10 },
+ { "mount-pty", no_argument, NULL, 12 },
{ NULL, 0, NULL, 0 }
};
static char optc[] = "hdvkpPwWF:r:i:l:";
@@ -538,6 +542,9 @@ static void parse_args(struct args *args, int argc, char *argv[])
case 11:
args->mntns = 1;
break;
+ case 12:
+ args->mnt_pty = 1;
+ break;
default:
usage(usage_str);
}
@@ -591,6 +598,9 @@ static void parse_args(struct args *args, int argc, char *argv[])
printf("Invalid used of both -l/--logfile and --logfile-fd\n");
exit(1);
}
+
+ if (args->mnt_pty)
+ args->mntns = 1;
}
static void report_exit_status(int status, char *str, int debug)
@@ -785,6 +795,10 @@ int main(int argc, char *argv[])
exit(1);
}
+ /* remount /dev/pts ? */
+ if (args.mnt_pty && ckpt_remount_devpts() < 0)
+ exit(1);
+
/* self-restart ends here: */
if (args.self) {
restart(getpid(), STDIN_FILENO, RESTART_TASKSELF, args.logfd);
@@ -916,6 +930,32 @@ static int ckpt_collect_child(struct ckpt_ctx *ctx)
return ckpt_parse_status(status, mimic, verbose);
}
+static int ckpt_remount_devpts(void)
+{
+ struct stat ptystat;
+
+ /* make sure /dev/ptmx is a link else we'll just break */
+ if (lstat("/dev/ptmx", &ptystat) < 0) {
+ perror("stat /dev/ptmx");
+ return -1;
+ }
+ if ((ptystat.st_mode & S_IFMT) != S_IFLNK) {
+ ckpt_err("Error: /dev/ptmx must be a link to /dev/pts/ptmx\n");
+ return -1;
+ }
+
+ if (umount2("/dev/pts", MNT_DETACH) < 0) {
+ perror("umount -l /dev/pts");
+ return -1;
+ }
+ if (mount("pts", "/dev/pts", "devpts", 0, "newinstance") < 0) {
+ perror("mount -t devpts -o newinstance");
+ return -1;
+ }
+
+ return 0;
+}
+
static int ckpt_close_files(void)
{
char fdpath[64], *endp;
--
1.6.3.3
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