[CRIU] [PATCH 4/7] tty: Prepare tracking bitmaps for multiple devpts handling
Pavel Emelyanov
xemul at virtuozzo.com
Wed Feb 8 00:37:55 PST 2017
On 02/02/2017 11:02 AM, Cyrill Gorcunov wrote:
> When multiple devpts will be addressed each bitmap
> have to belong own mount instance, so allocate them
> dinamically.
>
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
> criu/tty.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 105 insertions(+), 16 deletions(-)
>
> diff --git a/criu/tty.c b/criu/tty.c
> index 2c0c56c57515..5ee9b85d0019 100644
> --- a/criu/tty.c
> +++ b/criu/tty.c
> @@ -150,9 +150,6 @@ static LIST_HEAD(all_ttys);
> #define STTY_INDEX 1010
> #define INDEX_ERR (MAX_TTYS + 1)
>
> -static DECLARE_BITMAP(tty_bitmap, (MAX_TTYS << 1));
> -static DECLARE_BITMAP(tty_active_pairs, (MAX_TTYS << 1));
> -
> struct tty_driver {
> short type;
> short subtype;
> @@ -166,6 +163,47 @@ struct tty_driver {
> #define TTY_SUBTYPE_MASTER 0x0001
> #define TTY_SUBTYPE_SLAVE 0x0002
>
> +typedef struct tty_bitmap_s {
> + struct tty_bitmap_s *next;
> + unsigned long bitmap[BITS_TO_LONGS((MAX_TTYS << 1))];
> + int mnt_id;
> +} tty_bitmap_t;
> +
> +static tty_bitmap_t *tty_info_id_bitmap;
> +static tty_bitmap_t *tty_active_pairs_bitmap;
> +
> +static void tty_free_bitmap(tty_bitmap_t *root)
> +{
> + tty_bitmap_t *t, *next;
> +
> + for (t = root; t; t = next) {
> + next = t->next;
> + xfree(t);
> + }
> +}
> +
> +static unsigned long *tty_lookup_bitmap(tty_bitmap_t **root, int mnt_id)
It's much better to keep the bitmap on mount_info->private field
rather than introduce yet another list for it.
> +{
> + tty_bitmap_t *t, *prev;
> +
> + for (t = *root, prev = NULL; t; prev = t, t = t->next) {
> + if (t->mnt_id == mnt_id)
> + return t->bitmap;
> + }
> +
> + t = xzalloc(sizeof(*t));
> + if (!t)
> + return NULL;
> +
> + if (prev)
> + prev->next = t;
> + if (!*root)
> + *root = t;
> +
> + t->mnt_id = mnt_id;
> + return t->bitmap;
> +}
> +
> static int ptm_fd_get_index(int fd, const struct fd_parms *p)
> {
> int index;
> @@ -367,13 +405,13 @@ static int tty_get_index(u32 id)
> }
>
> /* Make sure the active pairs do exist */
> -static int tty_verify_active_pairs(void * unused)
> +static int __tty_verify_active_pairs(unsigned long *bitmap)
> {
> unsigned long i, unpaired_slaves = 0;
>
> - for_each_bit(i, tty_active_pairs) {
> + for_each_bit(i, bitmap) {
> if ((i % 2) == 0) {
> - if (test_bit(i + 1, tty_active_pairs)) {
> + if (test_bit(i + 1, bitmap)) {
> i++;
> continue;
> }
> @@ -399,6 +437,18 @@ static int tty_verify_active_pairs(void * unused)
> return 0;
> }
>
> +static int tty_verify_active_pairs(void *unused)
> +{
> + tty_bitmap_t *t;
> +
> + for (t = tty_active_pairs_bitmap; t; t = t->next) {
> + if (__tty_verify_active_pairs(t->bitmap))
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> static int tty_test_and_set(int bit, unsigned long *bitmap)
> {
> int ret;
> @@ -738,12 +788,11 @@ static bool tty_is_hung(struct tty_info *info)
> return info->tie->termios == NULL;
> }
>
> -static bool tty_has_active_pair(struct tty_info *info)
> +static bool tty_has_active_pair(struct tty_info *info, unsigned long *bitmap)
> {
> int d = tty_is_master(info) ? -1 : + 1;
>
> - return test_bit(info->tfe->tty_info_id + d,
> - tty_active_pairs);
> + return test_bit(info->tfe->tty_info_id + d, bitmap);
> }
>
> static void tty_show_pty_info(char *prefix, struct tty_info *info)
> @@ -1233,7 +1282,13 @@ static int tty_find_restoring_task(struct tty_info *info)
>
> if (info->tie->sid) {
> if (!tty_is_master(info)) {
> - if (tty_has_active_pair(info))
> + unsigned long *bitmap;
> +
> + bitmap = tty_lookup_bitmap(&tty_active_pairs_bitmap,
> + info->tfe->mnt_id);
> + if (!bitmap)
> + goto nobitmap;
> + if (tty_has_active_pair(info, bitmap))
> return 0;
> else
> goto shell_job;
> @@ -1263,9 +1318,15 @@ static int tty_find_restoring_task(struct tty_info *info)
>
> goto notask;
> } else {
> + unsigned long *bitmap;
> +
> if (tty_is_master(info))
> return 0;
> - if (tty_has_active_pair(info))
> + bitmap = tty_lookup_bitmap(&tty_active_pairs_bitmap,
> + info->tfe->mnt_id);
> + if (!bitmap)
> + goto nobitmap;
> + if (tty_has_active_pair(info, bitmap))
> return 0;
> }
>
> @@ -1279,6 +1340,9 @@ shell_job:
> notask:
> pr_err("No task found with sid %d\n", info->tie->sid);
> return -1;
> +nobitmap:
> + pr_err("No pairing bitmap for %#x\n", info->tfe->id);
> + return -1;
> }
>
> static int tty_setup_orphan_slavery(void)
> @@ -1594,8 +1658,18 @@ static int collect_one_tty(void *obj, ProtobufCMessage *msg, struct cr_img *i)
> * can't be used. Most likely they appear if a user has
> * dumped program when it was closing a peer.
> */
> - if (is_pty(info->driver) && info->tie->termios)
> - tty_test_and_set(info->tfe->tty_info_id, tty_active_pairs);
> + if (is_pty(info->driver) && info->tie->termios) {
> + unsigned long *bitmap;
> +
> + bitmap = tty_lookup_bitmap(&tty_active_pairs_bitmap,
> + info->tfe->mnt_id);
> + if (!bitmap) {
> + pr_err("No pairing bitmap for %#x\n", info->tfe->id);
> + return -1;
> + }
> +
> + tty_test_and_set(info->tfe->tty_info_id, bitmap);
> + }
>
> pr_info("Collected tty ID %#x (%s)\n", info->tfe->id, info->driver->name);
>
> @@ -1793,8 +1867,16 @@ static int dump_tty_info(int lfd, u32 id, const struct fd_parms *p, int mnt_id,
> * not yet supported by our tool and better to
> * inform a user about such situation.
> */
> - if (is_pty(driver))
> - tty_test_and_set(id, tty_active_pairs);
> + if (is_pty(driver)) {
> + unsigned long *bitmap;
> +
> + bitmap = tty_lookup_bitmap(&tty_active_pairs_bitmap, mnt_id);
> + if (!bitmap) {
> + pr_err("No pairing bitmap for %#x\n", id);
> + return -1;
> + }
> + tty_test_and_set(id, bitmap);
> + }
>
> info.termios = &termios;
> info.termios_locked = &termios_locked;
> @@ -1842,6 +1924,7 @@ static int dump_one_tty(int lfd, u32 id, const struct fd_parms *p)
> TtyFileEntry e = TTY_FILE_ENTRY__INIT;
> int ret = 0, index = -1, mnt_id;
> struct tty_driver *driver;
> + unsigned long *bitmap;
>
> pr_info("Dumping tty %d with id %#x\n", lfd, id);
>
> @@ -1906,7 +1989,11 @@ static int dump_one_tty(int lfd, u32 id, const struct fd_parms *p)
> * transport anyway.
> */
>
> - if (!tty_test_and_set(e.tty_info_id, tty_bitmap))
> + bitmap = tty_lookup_bitmap(&tty_info_id_bitmap, mnt_id);
> + if (!bitmap)
> + return -ENOMEM;
> +
> + if (!tty_test_and_set(e.tty_info_id, bitmap))
> ret = dump_tty_info(lfd, e.tty_info_id, p, mnt_id, driver, index);
>
> if (!ret)
> @@ -2150,4 +2237,6 @@ int tty_prep_fds(void)
> void tty_fini_fds(void)
> {
> close_service_fd(SELF_STDIN_OFF);
> + tty_free_bitmap(tty_info_id_bitmap);
> + tty_free_bitmap(tty_active_pairs_bitmap);
> }
>
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