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-rw-r--r--ftpfs/dir.c725
1 files changed, 725 insertions, 0 deletions
diff --git a/ftpfs/dir.c b/ftpfs/dir.c
new file mode 100644
index 00000000..5cde61a6
--- /dev/null
+++ b/ftpfs/dir.c
@@ -0,0 +1,725 @@
+/* Directory operations
+
+ Copyright (C) 1997 Free Software Foundation, Inc.
+ Written by Miles Bader <miles@gnu.ai.mit.edu>
+ This file is part of the GNU Hurd.
+
+ The GNU Hurd is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2, or (at
+ your option) any later version.
+
+ The GNU Hurd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
+
+#include <string.h>
+
+#include <hurd/netfs.h>
+
+#include "ftpfs.h"
+#include "ccache.h"
+
+/* Return an alloca'd string containing NAME appended to DIR's path; if
+ DIR_PFX_LEN is non-zero, the length of DIR's path is returned in it. */
+#define path_append(dir, name, dir_pfx_len) \
+({ \
+ struct ftpfs_dir *_dir = (dir); \
+ const char *_name = (name); \
+ size_t *_dir_pfx_len_p = (dir_pfx_len); \
+ size_t _dir_pfx_len = strlen (_dir->rmt_path) + 1; \
+ char *_path = alloca (_dir_pfx_len + strlen (_name) + 1); \
+ \
+ /* Form the composite name. */ \
+ if (_name && *_name) \
+ stpcpy (stpcpy (stpcpy (_path, _dir->rmt_path), "/"), _name); \
+ else \
+ { \
+ strcpy (_path, _dir->rmt_path); \
+ _dir_pfx_len--; \
+ } \
+ if (_dir_pfx_len_p) \
+ *_dir_pfx_len_p = _dir_pfx_len; \
+ \
+ _path; \
+})
+
+/* Free the directory entry E and all resources it consumes. */
+void
+free_entry (struct ftpfs_dir_entry *e)
+{
+ assert (! e->self_p); /* We should only free deleted nodes. */
+ free (e->name);
+ if (e->symlink_target)
+ free (e->symlink_target);
+ free (e);
+}
+
+/* Put the directory entry E into the hash table HTABLE, of length HTABLE_LEN. */
+static void
+insert (struct ftpfs_dir_entry *e,
+ struct ftpfs_dir_entry **htable, size_t htable_len)
+{
+ struct ftpfs_dir_entry **t = &htable[e->hv % htable_len];
+ if (*t)
+ (*t)->self_p = &e->next;
+ e->next = *t;
+ e->self_p = t;
+ *t = e;
+}
+
+/* Replace DIR's hashtable with a new one of length NEW_LEN, retaining all
+ existing entries. */
+static error_t
+rehash (struct ftpfs_dir *dir, size_t new_len)
+{
+ int i;
+ size_t old_len = dir->htable_len;
+ struct ftpfs_dir_entry **old_htable = dir->htable;
+ struct ftpfs_dir_entry **new_htable =
+ malloc (new_len * sizeof (struct ftpfs_dir_entry *));
+
+ if (! new_htable)
+ return ENOMEM;
+
+ for (i = 0; i < old_len; i++)
+ while (old_htable[i])
+ {
+ struct ftpfs_dir_entry *e = old_htable[i];
+
+ /* Remove E from the old table (don't bother to fixup
+ e->next->self_p). */
+ old_htable[i] = e->next;
+
+ insert (e, new_htable, new_len);
+ }
+
+ free (old_htable);
+
+ dir->htable = new_htable;
+ dir->htable_len = new_len;
+
+ return 0;
+}
+
+/* Calculate NAME's hash value. */
+static size_t
+hash (const char *name)
+{
+ size_t hv = 0;
+ while (*name)
+ hv = ((hv << 5) + *name++) & 0xFFFFFF;
+ return hv;
+}
+
+/* Lookup NAME in DIR and return its entry. If there is no such entry, and
+ ADD is true, then a new entry is allocated and returned, otherwise 0 is
+ returned (if ADD is true then 0 can be returned if a memory allocation
+ error occurs). */
+struct ftpfs_dir_entry *
+lookup (struct ftpfs_dir *dir, const char *name, int add)
+{
+ size_t hv = hash (name);
+ struct ftpfs_dir_entry *h = dir->htable[hv % dir->htable_len], *e = h;
+
+ while (e && strcmp (name, e->name) != 0)
+ e = e->next;
+
+ if (!e && add)
+ {
+ e = malloc (sizeof *e);
+ if (e)
+ {
+ e->hv = hv;
+ e->name = strdup (name);
+ e->dir = dir;
+ e->stat_timestamp = 0;
+ bzero (&e->stat, sizeof e->stat);
+ e->symlink_target = 0;
+ e->noent = 0;
+ e->valid = 0;
+ e->ordered_next = 0;
+ e->ordered_self_p = 0;
+ e->next = 0;
+ e->self_p = 0;
+ insert (e, dir->htable, dir->htable_len);
+ dir->num_entries++;
+ }
+ }
+
+ return e;
+}
+
+/* Remove E from its position in the ordered_next chain. */
+static void
+ordered_unlink (struct ftpfs_dir_entry *e)
+{
+ if (e->ordered_self_p)
+ *e->ordered_self_p = e->ordered_next;
+ if (e->ordered_next)
+ e->ordered_next->self_p = e->ordered_self_p;
+}
+
+/* Delete E from its directory, freeing any resources it holds. */
+static void
+delete (struct ftpfs_dir_entry *e, struct ftpfs_dir *dir)
+{
+ dir->num_entries--;
+
+ /* Take out of the hash chain. */
+ if (e->self_p)
+ *e->self_p = e->next;
+ if (e->next)
+ e->next->self_p = e->self_p;
+
+ /* This indicates a deleted entry. */
+ e->self_p = 0;
+ e->next = 0;
+
+ /* Take out of the directory ordered list. */
+ ordered_unlink (e);
+
+ /* Now stick in the deleted list. */
+}
+
+/* Clear the valid bit in all DIR's htable. */
+static void
+mark (struct ftpfs_dir *dir)
+{
+ size_t len = dir->htable_len, i;
+ struct ftpfs_dir_entry **htable = dir->htable, *e;
+
+ for (i = 0; i < len; i++)
+ for (e = htable[i]; e; e = e->next)
+ e->valid = 0;
+}
+
+/* Delete any entries in DIR which don't have their valid bit set. */
+static void
+sweep (struct ftpfs_dir *dir)
+{
+ size_t len = dir->htable_len, i;
+ struct ftpfs_dir_entry **htable = dir->htable, *e;
+
+ for (i = 0; i < len; i++)
+ for (e = htable[i]; e; e = e->next)
+ if (! e->valid)
+ delete (e, dir);
+}
+
+/* Inode numbers. */
+ino_t ftpfs_next_inode = 2;
+
+/* Update the directory entry for NAME to reflect ST and SYMLINK_TARGET.
+ True is returned if successful, or false if there was a memory allocation
+ error. TIMESTAMP is used to record the time of this update. */
+static struct ftpfs_dir_entry *
+update_entry (struct ftpfs_dir_entry *e, const struct stat *st,
+ const char *symlink_target, time_t timestamp, int no_lock)
+{
+ ino_t ino;
+
+ if (e->stat_timestamp == 0)
+ ino = ftpfs_next_inode++;
+ else
+ ino = e->stat.st_ino;
+
+ e->dirent_timestamp = timestamp;
+
+ e->symlink_target = symlink_target ? strdup (symlink_target) : 0;
+ e->stat = *st;
+ e->stat.st_ino = ino;
+ e->stat_timestamp = timestamp;
+
+ return e;
+}
+
+/* Add the timestamp TIMESTAMP to the set used to detect bulk stats, and
+ return true if there have been enough individual stats recently to call
+ for just refetching the whole directory. */
+static int
+need_bulk_stat (time_t timestamp, struct ftpfs_dir *dir)
+{
+ time_t period = dir->fs->params.bulk_stat_period;
+ unsigned limit = dir->fs->params.bulk_stat_limit;
+
+ if (timestamp > dir->bulk_stat_base_stamp + period * 3)
+ /* No stats done in a while, just start over. */
+ {
+ dir->bulk_stat_count_first_half = 1;
+ dir->bulk_stat_count_second_half = 0;
+ dir->bulk_stat_base_stamp = (timestamp / period) * period;
+ }
+ else if (timestamp > dir->bulk_stat_base_stamp + period * 2)
+ /* Start a new period, but keep the second half of the old one. */
+ {
+ dir->bulk_stat_count_first_half = dir->bulk_stat_count_second_half;
+ dir->bulk_stat_count_second_half = 1;
+ dir->bulk_stat_base_stamp += period;
+ }
+ else if (timestamp > dir->bulk_stat_base_stamp + period)
+ dir->bulk_stat_count_second_half++;
+ else
+ dir->bulk_stat_count_first_half++;
+
+ return
+ (dir->bulk_stat_count_first_half + dir->bulk_stat_count_second_half)
+ > limit;
+}
+
+static void
+reset_bulk_stat_info (struct ftpfs_dir *dir)
+{
+ dir->bulk_stat_count_first_half = 0;
+ dir->bulk_stat_count_second_half = 0;
+ dir->bulk_stat_base_stamp = 0;
+}
+
+/* State shared between ftpfs_dir_refresh and update_ordered_entry. */
+struct dir_fetch_state
+{
+ struct ftpfs_dir *dir;
+ struct ftpfs_dir_entry *prev_entry;
+ time_t timestamp;
+};
+
+/* Update the directory entry for NAME to reflect ST and SYMLINK_TARGET, also
+ rearranging the entries to reflect the order in which they are sent from
+ the server, and setting their valid bits so that obsolete entries can be
+ deleted. HOOK points to the state from ftpfs_dir_fetch. */
+static error_t
+update_ordered_entry (const char *name, const struct stat *st,
+ const char *symlink_target, void *hook)
+{
+ struct dir_fetch_state *rds = hook;
+ struct ftpfs_dir_entry *e = lookup (rds->dir, name, 1), *pe;
+
+ if (!e || !update_entry (e, st, symlink_target, rds->timestamp, 0))
+ return ENOMEM;
+
+ e->valid = 1;
+
+ assert (! e->ordered_self_p);
+ assert (! e->ordered_next);
+
+ /* Position E in the ordered chain. */
+ pe = rds->prev_entry; /* Previously seen entry. */
+ if (pe)
+ e->ordered_self_p = &pe->ordered_next; /* Put E after PE. */
+ else
+ e->ordered_self_p = &rds->dir->ordered; /* Put E at beginning. */
+ assert (! *e->ordered_self_p); /* There shouldn't be anything in E's place. */
+
+ *e->ordered_self_p = e; /* Put E there. */
+ rds->prev_entry = e; /* Put the next entry after this one. */
+
+ return 0;
+}
+
+/* Refresh DIR from the directory DIR_NAME in the filesystem FS. */
+static error_t
+refresh_dir (struct ftpfs_dir *dir, time_t timestamp)
+{
+ error_t err;
+ struct ftp_conn *conn;
+ struct dir_fetch_state rds;
+
+ if (dir->timestamp + dir->fs->params.dir_timeout >= timestamp)
+ /* We've already refreshed this directory recently. */
+ return 0;
+
+ err = ftpfs_get_ftp_conn (dir->fs, &conn);
+ if (err)
+ return err;
+
+ /* Clear DIR's ordered entry list. */
+ if (dir->ordered)
+ {
+ struct ftpfs_dir_entry *e, *next;
+ for (e = dir->ordered; e; e = next)
+ {
+ next = e->ordered_next;
+ e->ordered_next = 0;
+ e->ordered_self_p = 0;
+ }
+ dir->ordered = 0;
+ }
+
+ /* Mark directory entries so we can GC them later using sweep. */
+ mark (dir);
+
+ reset_bulk_stat_info (dir);
+
+ /* Refetch the directory from the server. */
+ rds.dir = dir;
+ rds.prev_entry = 0;
+ rds.timestamp = timestamp;
+ err = ftp_conn_get_stats (conn, dir->rmt_path, 1, update_ordered_entry, &rds);
+
+ if (! err)
+ /* GC any directory entries that weren't seen this time. */
+ {
+ dir->timestamp = timestamp;
+ sweep (dir);
+ }
+
+ ftpfs_release_ftp_conn (dir->fs, conn);
+
+ return err;
+}
+
+/* Refresh DIR. */
+error_t
+ftpfs_dir_refresh (struct ftpfs_dir *dir)
+{
+ time_t timestamp = NOW;
+ return refresh_dir (dir, timestamp);
+}
+
+/* State shared between ftpfs_dir_entry_refresh and update_old_entry. */
+struct refresh_entry_state
+{
+ struct ftpfs_dir_entry *entry;
+ time_t timestamp;
+ /* Prefix to skip at beginning of name returned from listing. */
+ const char *dir_pfx;
+ size_t dir_pfx_len;
+};
+
+/* Update the directory entry for NAME to reflect ST and SYMLINK_TARGET.
+ HOOK points to the state from ftpfs_dir_fetch_entry. */
+static error_t
+update_old_entry (const char *name, const struct stat *st,
+ const char *symlink_target, void *hook)
+{
+ struct refresh_entry_state *res = hook;
+
+ /* Skip the directory part of the name. */
+ if (strncmp (name, res->dir_pfx, res->dir_pfx_len) != 0)
+ return EGRATUITOUS;
+ else
+ name += res->dir_pfx_len;
+
+ if (strcmp (name, res->entry->name) != 0)
+ return EGRATUITOUS;
+
+ if (update_entry (res->entry, st, symlink_target, res->timestamp, 1))
+ return 0;
+ else
+ return ENOMEM;
+}
+
+/* Refresh stat information for NODE. This may actually refresh the whole
+ directory if that is deemed desirable. NODE should be locked. */
+error_t
+ftpfs_refresh_node (struct node *node)
+{
+ struct netnode *nn = node->nn;
+ struct ftpfs_dir_entry *entry = nn->dir_entry;
+
+ if (! entry)
+ /* This is a deleted node, don't attempt to do anything. */
+ return 0;
+ else
+ {
+ error_t err = 0;
+ time_t timestamp = NOW;
+ struct ftpfs_dir *dir = entry->dir;
+
+ mutex_lock (&dir->node->lock);
+
+ if (! entry->self_p)
+ /* This is a deleted entry, just awaiting disposal; do so. */
+ {
+ nn->dir_entry = 0;
+ free_entry (entry);
+ return 0;
+ }
+ else if (entry->stat_timestamp + dir->fs->params.stat_timeout < timestamp)
+ /* Stat information needs updating. */
+ if (need_bulk_stat (timestamp, dir))
+ /* Refetch the whole directory from the server. */
+ err = refresh_dir (entry->dir, timestamp);
+ else
+ {
+ struct ftp_conn *conn;
+ struct refresh_entry_state res;
+ const char *path = path_append (dir, entry->name, &res.dir_pfx_len);
+
+ res.entry = entry;
+ res.timestamp = timestamp;
+ res.dir_pfx = path;
+
+ err = ftpfs_get_ftp_conn (dir->fs, &conn);
+ if (! err)
+ {
+ err =
+ ftp_conn_get_stats (conn, path, 0, update_old_entry, &res);
+ ftpfs_release_ftp_conn (dir->fs, conn);
+ }
+ }
+
+ if ((entry->stat.st_mtime < node->nn_stat.st_mtime
+ || entry->stat.st_size != node->nn_stat.st_size)
+ && nn && nn->contents)
+ /* The file has changed. */
+ ccache_invalidate (nn->contents);
+
+ node->nn_stat = entry->stat;
+ if (!nn->dir && S_ISDIR (entry->stat.st_mode))
+ ftpfs_dir_create (nn->fs, node, nn->rmt_path, &nn->dir);
+
+ mutex_unlock (&dir->node->lock);
+
+ ftpfs_cache_node (node);
+
+ return err;
+ }
+}
+
+/* Remove NODE from its entry (if the entry is still valid, it will remain
+ without a node). NODE should be locked. */
+error_t
+ftpfs_detach_node (struct node *node)
+{
+ struct netnode *nn = node->nn;
+ struct ftpfs_dir_entry *entry = nn->dir_entry;
+
+ if (entry)
+ /* NODE is still attached to some entry, so detach it. */
+ {
+ struct ftpfs_dir *dir = entry->dir;
+
+ mutex_lock (&dir->node->lock);
+
+ if (entry->self_p)
+ /* Just detach NODE from the still active entry. */
+ entry->node = 0;
+ else
+ /* This is a deleted entry, just awaiting disposal; do so. */
+ {
+ nn->dir_entry = 0;
+ free_entry (entry);
+ }
+
+ if (--dir->num_live_entries == 0)
+ netfs_nput (dir->node);
+ else
+ mutex_unlock (&dir->node->lock);
+ }
+
+ return 0;
+}
+
+/* State shared between ftpfs_dir_lookup and update_new_entry. */
+struct new_entry_state
+{
+ time_t timestamp;
+ struct ftpfs_dir *dir;
+ struct ftpfs_dir_entry *entry;
+ /* Prefix to skip at beginning of name returned from listing. */
+ const char *dir_pfx;
+ size_t dir_pfx_len;
+};
+
+/* Update the directory entry for NAME to reflect ST and SYMLINK_TARGET.
+ HOOK->entry will be updated to reflect the new entry. */
+static error_t
+update_new_entry (const char *name, const struct stat *st,
+ const char *symlink_target, void *hook)
+{
+ struct ftpfs_dir_entry *e;
+ struct new_entry_state *nes = hook;
+
+ /* Skip the directory part of the name. */
+ if (strncmp (name, nes->dir_pfx, nes->dir_pfx_len) != 0)
+ return EGRATUITOUS;
+ else
+ name += nes->dir_pfx_len;
+
+ e = lookup (nes->dir, name, 1);
+ if (!e || !update_entry (e, st, symlink_target, nes->timestamp, 0))
+ return ENOMEM;
+
+ nes->entry = e;
+
+ return 0;
+}
+
+/* Lookup NAME in DIR, returning its entry, or an error. DIR's node should
+ be locked, and will be unlocked after returning; *NODE will contain the
+ result node, locked, and with an additional reference, or 0 if an error
+ occurs. */
+error_t
+ftpfs_dir_lookup (struct ftpfs_dir *dir, const char *name,
+ struct node **node)
+{
+ error_t err = 0;
+ time_t timestamp = NOW;
+ struct ftpfs_dir_entry *e;
+
+ if (strcmp (name, ".") == 0)
+ {
+ netfs_nref (dir->node);
+ *node = dir->node;
+ return 0;
+ }
+ else if (strcmp (name, "..") == 0)
+ {
+ if (dir->node->nn->dir_entry)
+ {
+ *node = dir->node->nn->dir_entry->dir->node;
+ mutex_lock (&(*node)->lock);
+ netfs_nref (*node);
+ }
+ else
+ {
+ err = ENOENT; /* No .. */
+ *node = 0;
+ }
+
+ mutex_unlock (&dir->node->lock);
+
+ return err;
+ }
+
+ e = lookup (dir, name, 0);
+ if (!e || e->dirent_timestamp + dir->fs->params.dirent_timeout < timestamp)
+ /* Try to fetch info about NAME. */
+ {
+ if (need_bulk_stat (timestamp, dir))
+ /* Refetch the whole directory from the server. */
+ {
+ err = refresh_dir (dir, timestamp);
+ if (! err)
+ e = lookup (dir, name, 0);
+ }
+ else
+ {
+ struct ftp_conn *conn;
+
+ err = ftpfs_get_ftp_conn (dir->fs, &conn);
+ if (! err)
+ {
+ struct new_entry_state nes;
+ const char *path = path_append (dir, name, &nes.dir_pfx_len);
+
+ nes.dir = dir;
+ nes.timestamp = timestamp;
+ nes.dir_pfx = path;
+
+ err = ftp_conn_get_stats (conn, path, 0, update_new_entry, &nes);
+ if (! err)
+ e = nes.entry;
+ else if (err == ENOENT)
+ {
+ e = lookup (dir, name, 1);
+ if (! e)
+ err = ENOMEM;
+ else
+ e->noent = 1; /* A negative entry. */
+ }
+
+ ftpfs_release_ftp_conn (dir->fs, conn);
+ }
+ }
+ }
+
+ if (! err)
+ if (e && !e->noent)
+ /* We've got a dir entry, get a node for it. */
+ {
+ /* If there's already a node, add a ref so that it doesn't go away. */
+ spin_lock (&netfs_node_refcnt_lock);
+ if (e->node)
+ e->node->references++;
+ spin_unlock (&netfs_node_refcnt_lock);
+
+ if (! e->node)
+ /* No node; make one and install it into E. */
+ {
+ const char *path = path_append (dir, name, 0);
+ err = ftpfs_create_node (e, path, &e->node);
+ if (!err && dir->num_live_entries++ == 0)
+ /* Keep a reference to dir's node corresponding to children. */
+ {
+ spin_lock (&netfs_node_refcnt_lock);
+ dir->node->references++;
+ spin_unlock (&netfs_node_refcnt_lock);
+ }
+ }
+
+ if (! err)
+ {
+ *node = e->node;
+ mutex_unlock (&dir->node->lock);
+ mutex_lock (&e->node->lock);
+ }
+ }
+ else
+ err = ENOENT;
+
+ if (err)
+ {
+ *node = 0;
+ mutex_unlock (&dir->node->lock);
+ }
+
+ return err;
+}
+
+/* Return in DIR a new ftpfs directory, in the filesystem FS, with node NODE
+ and remote path RMT_PATH. RMT_PATH is *not copied*, so it shouldn't ever
+ change while this directory is active. */
+error_t
+ftpfs_dir_create (struct ftpfs *fs, struct node *node, const char *rmt_path,
+ struct ftpfs_dir **dir)
+{
+ struct ftpfs_dir *new = malloc (sizeof (struct ftpfs_dir));
+
+ if (! new)
+ return ENOMEM;
+
+ /* Hold a reference to the new dir's node. */
+ spin_lock (&netfs_node_refcnt_lock);
+ node->references++;
+ spin_unlock (&netfs_node_refcnt_lock);
+
+ new->num_entries = 0;
+ new->num_live_entries = 0;
+ new->htable_len = 5;
+ new->htable = malloc (new->htable_len * sizeof (struct ftpfs_dir_entry *));
+ bzero (new->htable, sizeof *new->htable * new->htable_len);
+ new->ordered = 0;
+ new->rmt_path = rmt_path;
+ new->fs = fs;
+ new->node = node;
+ new->timestamp = 0;
+ new->bulk_stat_base_stamp = 0;
+ new->bulk_stat_count_first_half = 0;
+ new->bulk_stat_count_second_half = 0;
+
+ *dir = new;
+
+ return 0;
+}
+
+void
+ftpfs_dir_free (struct ftpfs_dir *dir)
+{
+ /* Free all entries. */
+ mark (dir);
+ sweep (dir);
+
+ if (dir->htable)
+ free (dir->htable);
+
+ netfs_nrele (dir->node);
+
+ free (dir);
+}