[CRIU] [PATCH 6/7] tty: Add support for multiple devpts instances
Pavel Emelyanov
xemul at virtuozzo.com
Tue Jan 31 03:34:38 PST 2017
On 01/21/2017 04:11 PM, Cyrill Gorcunov wrote:
> To support several devpts instances we need to distinguish them
> from each other, thus now use use @mnt_id from dump stage to
> link tty file entries and tty info entries with each other.
>
> To track if we need to dump particular tty info entry
> and test if all peers are present instead of static
> bitmaps we use dynamics: one per mount.
>
> Also to be able to create master/slave pty peers
> from different mounts the pty_alloc_reg been
> reworked and hopefully simplified.
>
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
> criu/tty.c | 239 +++++++++++++++++++++++++++++++++++++++++++------------------
> 1 file changed, 170 insertions(+), 69 deletions(-)
>
> diff --git a/criu/tty.c b/criu/tty.c
> index bbdb3ca2e071..2560b27a855c 100644
> --- a/criu/tty.c
> +++ b/criu/tty.c
> @@ -28,11 +28,13 @@
> #include "files-reg.h"
> #include "namespaces.h"
> #include "external.h"
> +#include "filesystems.h"
> #include "mount.h"
>
> #include "protobuf.h"
> #include "util.h"
> #include "images/tty.pb-c.h"
> +#include "images/mnt.pb-c.h"
>
> #include "parasite-syscall.h"
> #include "parasite.h"
> @@ -150,9 +152,6 @@ 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));
> -
Split bitmap rework into separate patch, please.
> struct tty_driver {
> short type;
> short subtype;
> @@ -166,6 +165,47 @@ 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)
> +{
> + 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 +407,13 @@ 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 +439,18 @@ 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;
> @@ -414,12 +466,41 @@ static int tty_test_and_set(int bit, unsigned long *bitmap)
> * in the image file, ie obsolete interface has been used on
> * checkpoint.
> */
> -static struct file_desc *pty_alloc_reg(struct tty_info *info, bool add)
> +static struct file_desc *pty_alloc_reg(struct tty_info *info, bool add, bool invert)
Plz, describe the new argument. What is it for?
> {
> TtyFileEntry *tfe = info->tfe;
> - const size_t namelen = 64;
> struct reg_file_info *r;
> static struct file_desc_ops noops = {};
> + struct mount_info *mi;
> + size_t namelen;
> + bool need_pts;
> +
> + mi = lookup_mnt_id(info->tfe->mnt_id);
> + if (!mi) {
> + pr_err("Can't resolve mnt_id %#x\n", info->tfe->mnt_id);
> + return NULL;
> + }
> +
> + if ((tty_is_master(info) && !invert) ||
> + (!tty_is_master(info) && invert)) {
> + need_pts = false;
> + } else {
> + need_pts = true;
> +
> + if (info->link) {
> + struct reg_file_info *rfi = container_of(info->link->reg_d,
> + struct reg_file_info, d);
> + pr_debug("Trying to use link: %s\n", rfi->path);
> + mi = lookup_mnt_id(info->link->tfe->mnt_id);
> + if (!mi) {
> + pr_err("Can't resolve link mnt_id %#x\n", info->tfe->mnt_id);
> + return NULL;
> + }
> + pr_debug("Mount at %s\n", mi->mountpoint);
> + }
> + }
> +
> + namelen = strlen(mi->mountpoint) + 64;
>
> r = xzalloc(sizeof(*r) + sizeof(*r->rfe) + namelen);
> if (!r)
> @@ -429,11 +510,12 @@ static struct file_desc *pty_alloc_reg(struct tty_info *info, bool add)
> reg_file_entry__init(r->rfe);
>
> r->rfe->name = (void *)r + sizeof(*r) + sizeof(*r->rfe);
> - if (tty_is_master(info))
> - strcpy(r->rfe->name, "/dev/ptmx");
> +
> + if (!need_pts)
> + snprintf(r->rfe->name, namelen, "%s/ptmx", mi->mountpoint);
> else
> - snprintf(r->rfe->name, namelen, "/dev/pts/%u",
> - info->tie->pty->index);
> + snprintf(r->rfe->name, namelen, "%s/%u",
> + mi->mountpoint, info->tie->pty->index);
>
> if (add)
> file_desc_add(&r->d, tfe->id, &noops);
> @@ -464,52 +546,32 @@ static struct file_desc *pty_alloc_reg(struct tty_info *info, bool add)
> */
> static struct reg_file_info *pty_alloc_fake_reg(struct tty_info *info, int subtype)
> {
> - struct reg_file_info *new, *orig;
> struct file_desc *fake_desc;
> -
> - pr_debug("Allocating fake descriptor for %#x (reg_d %p)\n",
> - info->tfe->id, info->reg_d);
> + struct reg_file_info *rfi;
> + bool invert;
>
> BUG_ON(!info->reg_d);
> BUG_ON(!is_pty(info->driver));
>
> - fake_desc = pty_alloc_reg(info, false);
> - if (!fake_desc)
> - return NULL;
> + if ((subtype == TTY_SUBTYPE_MASTER && tty_is_master(info)) ||
> + (subtype == TTY_SUBTYPE_SLAVE && !tty_is_master(info)))
> + invert = false;
> + else
> + invert = true;
>
> - orig = container_of(info->reg_d, struct reg_file_info, d);
> - new = container_of(fake_desc, struct reg_file_info, d);
> + rfi = container_of(info->reg_d, struct reg_file_info, d);
> + pr_debug("Allocating fake descriptor for %#x (path %s, invert %d)\n",
> + info->tfe->id, rfi->path, invert);
>
> - if ((subtype == TTY_SUBTYPE_MASTER && tty_is_master(info)) ||
> - (subtype == TTY_SUBTYPE_SLAVE && !tty_is_master(info))) {
> - new->path = xstrdup(orig->path);
> - new->rfe->name = &new->path[1];
> - } else {
> - char *pos = strrchr(orig->rfe->name, '/');
> - size_t len = strlen(orig->rfe->name) + 1;
> - size_t slash_at = pos - orig->rfe->name;
> - char *inverted_path = xmalloc(len + 32);
> -
> - BUG_ON(!pos || !inverted_path);
> -
> - memcpy(inverted_path, orig->rfe->name, slash_at + 1);
> - if (subtype == TTY_SUBTYPE_MASTER) {
> - inverted_path[slash_at + 1] = '\0';
> - strcat(inverted_path, "ptmx");
> - } else {
> - if (slash_at >= 3 && strncmp(&inverted_path[slash_at - 3], "pts", 3))
> - snprintf(&inverted_path[slash_at + 1], 10, "pts/%u",
> - info->tie->pty->index);
> - else
> - snprintf(&inverted_path[slash_at + 1], 10, "%u",
> - info->tie->pty->index);
> - }
> + fake_desc = pty_alloc_reg(info, false, invert);
> + if (!fake_desc)
> + return NULL;
>
> - new->rfe->name = inverted_path;
> - new->path = &inverted_path[1];
> - }
> + rfi = container_of(fake_desc, struct reg_file_info, d);
> + pr_debug("Allocated fake descriptor for %#x as (path %s, invert %d)\n",
> + info->tfe->id, rfi->path, invert);
>
> - return new;
> + return rfi;
> }
>
> #define pty_alloc_fake_master(info) pty_alloc_fake_reg(info, TTY_SUBTYPE_MASTER)
> @@ -518,7 +580,6 @@ static struct reg_file_info *pty_alloc_fake_reg(struct tty_info *info, int subty
> static void pty_free_fake_reg(struct reg_file_info **r)
> {
> if (*r) {
> - xfree((*r)->rfe->name);
> xfree((*r));
> *r = NULL;
> }
> @@ -739,12 +800,11 @@ 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)
> @@ -1214,7 +1274,13 @@ 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;
> @@ -1244,9 +1310,15 @@ 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;
> }
>
> @@ -1260,6 +1332,9 @@ 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)
> @@ -1320,7 +1395,8 @@ static int tty_setup_slavery(void * unused)
> list_for_each_entry_continue(peer, &all_ttys, list) {
> if (!is_pty(peer->driver) || peer->link)
> continue;
> - if (peer->tie->pty->index == info->tie->pty->index) {
> + if (peer->tie->pty->index == info->tie->pty->index &&
> + peer->tie->mnt_id == info->tie->mnt_id) {
> info->link = peer;
> peer->link = info;
>
> @@ -1351,7 +1427,8 @@ static int tty_setup_slavery(void * unused)
> if (!peer->tie->sid || peer->ctl_tty ||
> peer->driver->type == TTY_TYPE__CTTY)
> continue;
> - if (peer->tie->sid == info->tie->sid) {
> + if (peer->tie->sid == info->tie->sid &&
> + peer->tie->mnt_id == info->tie->mnt_id) {
> pr_debug(" `- slave %#x\n", peer->tfe->id);
> peer->ctl_tty = info;
> }
> @@ -1368,7 +1445,8 @@ static int tty_setup_slavery(void * unused)
> list_for_each_entry_safe_continue(peer, m, &all_ttys, list) {
> if (!is_pty(peer->driver))
> continue;
> - if (peer->tie->pty->index != info->tie->pty->index)
> + if (peer->tie->pty->index != info->tie->pty->index ||
> + peer->tie->mnt_id != info->tie->mnt_id)
> continue;
>
> if (tty_find_restoring_task(peer))
> @@ -1444,12 +1522,12 @@ static int verify_info(struct tty_info *info)
> return 0;
> }
>
> -static TtyInfoEntry *lookup_tty_info_entry(u32 id)
> +static TtyInfoEntry *lookup_tty_info_entry(u32 id, int mnt_id)
> {
> struct tty_info_entry *e;
>
> list_for_each_entry(e, &all_tty_info_entries, list) {
> - if (e->tie->id == id)
> + if (e->tie->id == id && e->tie->mnt_id == mnt_id)
> return e->tie;
> }
>
> @@ -1516,7 +1594,7 @@ static int collect_one_tty(void *obj, ProtobufCMessage *msg, struct cr_img *i)
> info->tfe->mnt_id = 0;
> }
>
> - info->tie = lookup_tty_info_entry(info->tfe->tty_info_id);
> + info->tie = lookup_tty_info_entry(info->tfe->tty_info_id, info->tfe->mnt_id);
> if (!info->tie) {
> pr_err("No tty-info-id %#x found on id %#x\n",
> info->tfe->tty_info_id, info->tfe->id);
> @@ -1555,7 +1633,7 @@ static int collect_one_tty(void *obj, ProtobufCMessage *msg, struct cr_img *i)
> return -1;
>
> if (is_pty(info->driver)) {
> - info->reg_d = pty_alloc_reg(info, true);
> + info->reg_d = pty_alloc_reg(info, true, false);
> if (!info->reg_d) {
> pr_err("Can't generate new reg descriptor for id %#x\n",
> info->tfe->id);
> @@ -1575,8 +1653,16 @@ 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 = 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);
>
> @@ -1613,7 +1699,8 @@ static int collect_one_tty_data(void *obj, ProtobufCMessage *msg, struct cr_img
> tdo->tde->tty_id, (size_t)tdo->tde->data.len);
>
> list_for_each_entry(info, &all_ttys, list) {
> - if (tdo->tde->tty_id == info->tie->id) {
> + if (tdo->tde->tty_id == info->tie->id &&
> + tdo->tde->mnt_id == info->tie->mnt_id) {
> info->tty_data = tdo;
> return 0;
> }
> @@ -1774,8 +1861,14 @@ 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 = 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;
> @@ -1823,6 +1916,7 @@ 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);
>
> @@ -1877,7 +1971,11 @@ 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)
> @@ -2053,7 +2151,8 @@ static int tty_dump_queued_data(void)
> if (!is_pty(peer->driver) || peer->link)
> continue;
>
> - if (peer->index == dinfo->index) {
> + if (peer->index == dinfo->index &&
> + peer->mnt_id == dinfo->mnt_id) {
> dinfo->link = peer;
> peer->link = dinfo;
> pr_debug("Link PTYs (%#x)\n", dinfo->id);
> @@ -2121,4 +2220,6 @@ 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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