Serge E. Hallyn wrote:
> Quoting Oren Laadan (orenl@xxxxxxxxxxxxxxx):
>> 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) {
>
> How about making that
>
> if (mount("pts", "/dev/pts", "devpts", 0, "ptmxmode=666,newinstance")
> < 0) {
>
> (or take that as another arg if you must)? Otherwise restarting
> non-root-owned tasks not only ends up with tasks not able to create
> a new terminal, but you can't externally fix that since the mount
> is private...
Ok. And also either umount() won't fail by default.
Oren.
>
>> + 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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