/* Cache handling for group lookup.
- Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+ Copyright (C) 1998-2013 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
+ This program 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; version 2 of the License, or
+ (at your option) any later version.
- The GNU C Library is distributed in the hope that it will be useful,
+ This program 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
- Lesser General Public License for more details.
+ 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 Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <http://www.gnu.org/licenses/>. */
+#include <alloca.h>
+#include <assert.h>
#include <errno.h>
#include <error.h>
#include <grp.h>
+#include <libintl.h>
+#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
-#include <libintl.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <stackinfo.h>
#include "nscd.h"
#include "dbg_log.h"
+#ifdef HAVE_SENDFILE
+# include <kernel-features.h>
+#endif
/* This is the standard reply in case the service is disabled. */
static const gr_response_header disabled =
{
- version: NSCD_VERSION,
- found: -1,
- gr_name_len: 0,
- gr_passwd_len: 0,
- gr_gid: -1,
- gr_mem_cnt: 0,
+ .version = NSCD_VERSION,
+ .found = -1,
+ .gr_name_len = 0,
+ .gr_passwd_len = 0,
+ .gr_gid = -1,
+ .gr_mem_cnt = 0,
};
/* This is the struct describing how to write this record. */
const struct iovec grp_iov_disabled =
{
- iov_base: (void *) &disabled,
- iov_len: sizeof (disabled)
+ .iov_base = (void *) &disabled,
+ .iov_len = sizeof (disabled)
};
/* This is the standard reply in case we haven't found the dataset. */
static const gr_response_header notfound =
{
- version: NSCD_VERSION,
- found: 0,
- gr_name_len: 0,
- gr_passwd_len: 0,
- gr_gid: -1,
- gr_mem_cnt: 0,
-};
-
-/* This is the struct describing how to write this record. */
-static const struct iovec iov_notfound =
-{
- iov_base: (void *) ¬found,
- iov_len: sizeof (notfound)
+ .version = NSCD_VERSION,
+ .found = 0,
+ .gr_name_len = 0,
+ .gr_passwd_len = 0,
+ .gr_gid = -1,
+ .gr_mem_cnt = 0,
};
-struct groupdata
-{
- gr_response_header resp;
- char strdata[0];
-};
-
-
-static void
-cache_addgr (struct database *db, int fd, request_header *req, void *key,
- struct group *grp, uid_t owner)
+static time_t
+cache_addgr (struct database_dyn *db, int fd, request_header *req,
+ const void *key, struct group *grp, uid_t owner,
+ struct hashentry *const he, struct datahead *dh, int errval)
{
+ bool all_written = true;
ssize_t total;
- ssize_t written;
time_t t = time (NULL);
- if (grp == NULL)
- {
- /* We have no data. This means we send the standard reply for this
- case. */
- void *copy;
-
- total = sizeof (notfound);
-
- written = writev (fd, &iov_notfound, 1);
+ /* We allocate all data in one memory block: the iov vector,
+ the response header and the dataset itself. */
+ struct dataset
+ {
+ struct datahead head;
+ gr_response_header resp;
+ char strdata[0];
+ } *dataset;
- copy = malloc (req->key_len);
- if (copy == NULL)
- error (EXIT_FAILURE, errno, _("while allocating key copy"));
- memcpy (copy, key, req->key_len);
+ assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
- /* Compute the timeout time. */
- t += db->negtimeout;
-
- /* Now get the lock to safely insert the records. */
- pthread_rwlock_rdlock (&db->lock);
+ time_t timeout = MAX_TIMEOUT_VALUE;
+ if (grp == NULL)
+ {
+ if (he != NULL && errval == EAGAIN)
+ {
+ /* If we have an old record available but cannot find one
+ now because the service is not available we keep the old
+ record and make sure it does not get removed. */
+ if (reload_count != UINT_MAX)
+ /* Do not reset the value if we never not reload the record. */
+ dh->nreloads = reload_count - 1;
- cache_add (req->type, copy, req->key_len, ¬found,
- sizeof (notfound), (void *) -1, 0, t, db, owner);
+ /* Reload with the same time-to-live value. */
+ timeout = dh->timeout = t + db->postimeout;
- pthread_rwlock_unlock (&db->lock);
+ total = 0;
+ }
+ else
+ {
+ /* We have no data. This means we send the standard reply for this
+ case. */
+ total = sizeof (notfound);
+
+ if (fd != -1
+ && TEMP_FAILURE_RETRY (send (fd, ¬found, total,
+ MSG_NOSIGNAL)) != total)
+ all_written = false;
+
+ /* If we have a transient error or cannot permanently store
+ the result, so be it. */
+ if (errno == EAGAIN || __builtin_expect (db->negtimeout == 0, 0))
+ {
+ /* Mark the old entry as obsolete. */
+ if (dh != NULL)
+ dh->usable = false;
+ }
+ else if ((dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len, 1)) != NULL)
+ {
+ dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
+ dataset->head.recsize = total;
+ dataset->head.notfound = true;
+ dataset->head.nreloads = 0;
+ dataset->head.usable = true;
+
+ /* Compute the timeout time. */
+ timeout = dataset->head.timeout = t + db->negtimeout;
+
+ /* This is the reply. */
+ memcpy (&dataset->resp, ¬found, total);
+
+ /* Copy the key data. */
+ memcpy (dataset->strdata, key, req->key_len);
+
+ /* If necessary, we also propagate the data to disk. */
+ if (db->persistent)
+ {
+ // XXX async OK?
+ uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
+ msync ((void *) pval,
+ ((uintptr_t) dataset & pagesize_m1)
+ + sizeof (struct dataset) + req->key_len, MS_ASYNC);
+ }
+
+ (void) cache_add (req->type, &dataset->strdata, req->key_len,
+ &dataset->head, true, db, owner, he == NULL);
+
+ pthread_rwlock_unlock (&db->lock);
+
+ /* Mark the old entry as obsolete. */
+ if (dh != NULL)
+ dh->usable = false;
+ }
+ }
}
else
{
/* Determine the I/O structure. */
- struct groupdata *data;
size_t gr_name_len = strlen (grp->gr_name) + 1;
size_t gr_passwd_len = strlen (grp->gr_passwd) + 1;
size_t gr_mem_cnt = 0;
size_t gr_mem_len_total = 0;
char *gr_name;
char *cp;
- char buf[12];
+ const size_t key_len = strlen (key);
+ const size_t buf_len = 3 * sizeof (grp->gr_gid) + key_len + 1;
+ size_t alloca_used = 0;
+ char *buf = alloca_account (buf_len, alloca_used);
ssize_t n;
size_t cnt;
/* We need this to insert the `bygid' entry. */
- n = snprintf (buf, sizeof (buf), "%d", grp->gr_gid) + 1;
+ int key_offset;
+ n = snprintf (buf, buf_len, "%d%c%n%s", grp->gr_gid, '\0',
+ &key_offset, (char *) key) + 1;
/* Determine the length of all members. */
while (grp->gr_mem[gr_mem_cnt])
++gr_mem_cnt;
- gr_mem_len = (uint32_t *) alloca (gr_mem_cnt * sizeof (uint32_t));
+ gr_mem_len = alloca_account (gr_mem_cnt * sizeof (uint32_t), alloca_used);
for (gr_mem_cnt = 0; grp->gr_mem[gr_mem_cnt]; ++gr_mem_cnt)
{
gr_mem_len[gr_mem_cnt] = strlen (grp->gr_mem[gr_mem_cnt]) + 1;
gr_mem_len_total += gr_mem_len[gr_mem_cnt];
}
- /* We allocate all data in one memory block: the iov vector,
- the response header and the dataset itself. */
- total = (sizeof (struct groupdata)
+ total = (offsetof (struct dataset, strdata)
+ gr_mem_cnt * sizeof (uint32_t)
+ gr_name_len + gr_passwd_len + gr_mem_len_total);
- data = (struct groupdata *) malloc (total + n);
- if (data == NULL)
- /* There is no reason to go on. */
- error (EXIT_FAILURE, errno, _("while allocating cache entry"));
- data->resp.found = 1;
- data->resp.gr_name_len = gr_name_len;
- data->resp.gr_passwd_len = gr_passwd_len;
- data->resp.gr_gid = grp->gr_gid;
- data->resp.gr_mem_cnt = gr_mem_cnt;
+ /* If we refill the cache, first assume the reconrd did not
+ change. Allocate memory on the cache since it is likely
+ discarded anyway. If it turns out to be necessary to have a
+ new record we can still allocate real memory. */
+ bool dataset_temporary = false;
+ bool dataset_malloced = false;
+ dataset = NULL;
- cp = data->strdata;
+ if (he == NULL)
+ dataset = (struct dataset *) mempool_alloc (db, total + n, 1);
+
+ if (dataset == NULL)
+ {
+ /* We cannot permanently add the result in the moment. But
+ we can provide the result as is. Store the data in some
+ temporary memory. */
+ if (! __libc_use_alloca (alloca_used + total + n))
+ {
+ dataset = malloc (total + n);
+ /* Perhaps we should log a message that we were unable
+ to allocate memory for a large request. */
+ if (dataset == NULL)
+ goto out;
+ dataset_malloced = true;
+ }
+ else
+ dataset = alloca_account (total + n, alloca_used);
+
+ /* We cannot add this record to the permanent database. */
+ dataset_temporary = true;
+ }
+
+ dataset->head.allocsize = total + n;
+ dataset->head.recsize = total - offsetof (struct dataset, resp);
+ dataset->head.notfound = false;
+ dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
+ dataset->head.usable = true;
+
+ /* Compute the timeout time. */
+ timeout = dataset->head.timeout = t + db->postimeout;
+
+ dataset->resp.version = NSCD_VERSION;
+ dataset->resp.found = 1;
+ dataset->resp.gr_name_len = gr_name_len;
+ dataset->resp.gr_passwd_len = gr_passwd_len;
+ dataset->resp.gr_gid = grp->gr_gid;
+ dataset->resp.gr_mem_cnt = gr_mem_cnt;
+
+ cp = dataset->strdata;
/* This is the member string length array. */
cp = mempcpy (cp, gr_mem_len, gr_mem_cnt * sizeof (uint32_t));
/* Finally the stringified GID value. */
memcpy (cp, buf, n);
+ char *key_copy = cp + key_offset;
+ assert (key_copy == (char *) rawmemchr (cp, '\0') + 1);
- /* Write the result. */
- written = TEMP_FAILURE_RETRY (write (fd, &data->resp, total));
-
- /* Compute the timeout time. */
- t += db->postimeout;
-
- /* Now get the lock to safely insert the records. */
- pthread_rwlock_rdlock (&db->lock);
+ assert (cp == dataset->strdata + total - offsetof (struct dataset,
+ strdata));
- /* We have to add the value for both, byname and byuid. */
- cache_add (GETGRBYNAME, gr_name, gr_name_len, data,
- total, data, 0, t, db, owner);
-
- cache_add (GETGRBYGID, cp, n, data, total, data, 1, t, db, owner);
+ /* Now we can determine whether on refill we have to create a new
+ record or not. */
+ if (he != NULL)
+ {
+ assert (fd == -1);
+
+ if (total + n == dh->allocsize
+ && total - offsetof (struct dataset, resp) == dh->recsize
+ && memcmp (&dataset->resp, dh->data,
+ dh->allocsize - offsetof (struct dataset, resp)) == 0)
+ {
+ /* The data has not changed. We will just bump the
+ timeout value. Note that the new record has been
+ allocated on the stack and need not be freed. */
+ dh->timeout = dataset->head.timeout;
+ ++dh->nreloads;
+
+ /* If the new record was allocated via malloc, then we must free
+ it here. */
+ if (dataset_malloced)
+ free (dataset);
+ }
+ else
+ {
+ /* We have to create a new record. Just allocate
+ appropriate memory and copy it. */
+ struct dataset *newp
+ = (struct dataset *) mempool_alloc (db, total + n, 1);
+ if (newp != NULL)
+ {
+ /* Adjust pointers into the memory block. */
+ gr_name = (char *) newp + (gr_name - (char *) dataset);
+ cp = (char *) newp + (cp - (char *) dataset);
+ key_copy = (char *) newp + (key_copy - (char *) dataset);
+
+ dataset = memcpy (newp, dataset, total + n);
+ dataset_temporary = false;
+ }
+
+ /* Mark the old record as obsolete. */
+ dh->usable = false;
+ }
+ }
+ else
+ {
+ /* We write the dataset before inserting it to the database
+ since while inserting this thread might block and so would
+ unnecessarily let the receiver wait. */
+ assert (fd != -1);
+
+#ifdef HAVE_SENDFILE
+ if (__builtin_expect (db->mmap_used, 1) && ! dataset_temporary)
+ {
+ assert (db->wr_fd != -1);
+ assert ((char *) &dataset->resp > (char *) db->data);
+ assert ((char *) dataset - (char *) db->head
+ + total
+ <= (sizeof (struct database_pers_head)
+ + db->head->module * sizeof (ref_t)
+ + db->head->data_size));
+ ssize_t written = sendfileall (fd, db->wr_fd,
+ (char *) &dataset->resp
+ - (char *) db->head,
+ dataset->head.recsize);
+ if (written != dataset->head.recsize)
+ {
+# ifndef __ASSUME_SENDFILE
+ if (written == -1 && errno == ENOSYS)
+ goto use_write;
+# endif
+ all_written = false;
+ }
+ }
+ else
+# ifndef __ASSUME_SENDFILE
+ use_write:
+# endif
+#endif
+ if (writeall (fd, &dataset->resp, dataset->head.recsize)
+ != dataset->head.recsize)
+ all_written = false;
+ }
- pthread_rwlock_unlock (&db->lock);
+ /* Add the record to the database. But only if it has not been
+ stored on the stack. */
+ if (! dataset_temporary)
+ {
+ /* If necessary, we also propagate the data to disk. */
+ if (db->persistent)
+ {
+ // XXX async OK?
+ uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
+ msync ((void *) pval,
+ ((uintptr_t) dataset & pagesize_m1) + total + n,
+ MS_ASYNC);
+ }
+
+ /* NB: in the following code we always must add the entry
+ marked with FIRST first. Otherwise we end up with
+ dangling "pointers" in case a latter hash entry cannot be
+ added. */
+ bool first = true;
+
+ /* If the request was by GID, add that entry first. */
+ if (req->type == GETGRBYGID)
+ {
+ if (cache_add (GETGRBYGID, cp, key_offset, &dataset->head, true,
+ db, owner, he == NULL) < 0)
+ goto out;
+
+ first = false;
+ }
+ /* If the key is different from the name add a separate entry. */
+ else if (strcmp (key_copy, gr_name) != 0)
+ {
+ if (cache_add (GETGRBYNAME, key_copy, key_len + 1,
+ &dataset->head, true, db, owner, he == NULL) < 0)
+ goto out;
+
+ first = false;
+ }
+
+ /* We have to add the value for both, byname and byuid. */
+ if ((req->type == GETGRBYNAME || db->propagate)
+ && __builtin_expect (cache_add (GETGRBYNAME, gr_name,
+ gr_name_len,
+ &dataset->head, first, db, owner,
+ he == NULL)
+ == 0, 1))
+ {
+ if (req->type == GETGRBYNAME && db->propagate)
+ (void) cache_add (GETGRBYGID, cp, key_offset, &dataset->head,
+ false, db, owner, false);
+ }
+
+ out:
+ pthread_rwlock_unlock (&db->lock);
+ }
}
- if (__builtin_expect (written != total, 0) && debug_level > 0)
+ if (__builtin_expect (!all_written, 0) && debug_level > 0)
{
char buf[256];
dbg_log (_("short write in %s: %s"), __FUNCTION__,
strerror_r (errno, buf, sizeof (buf)));
}
+
+ return timeout;
}
-void
-addgrbyname (struct database *db, int fd, request_header *req,
- void *key, uid_t uid)
+union keytype
+{
+ void *v;
+ gid_t g;
+};
+
+
+static int
+lookup (int type, union keytype key, struct group *resultbufp, char *buffer,
+ size_t buflen, struct group **grp)
+{
+ if (type == GETGRBYNAME)
+ return __getgrnam_r (key.v, resultbufp, buffer, buflen, grp);
+ else
+ return __getgrgid_r (key.g, resultbufp, buffer, buflen, grp);
+}
+
+
+static time_t
+addgrbyX (struct database_dyn *db, int fd, request_header *req,
+ union keytype key, const char *keystr, uid_t uid,
+ struct hashentry *he, struct datahead *dh)
{
/* Search for the entry matching the key. Please note that we don't
look again in the table whether the dataset is now available. We
simply insert it. It does not matter if it is in there twice. The
pruning function only will look at the timestamp. */
- int buflen = 256;
- char *buffer = alloca (buflen);
+ size_t buflen = 1024;
+ char *buffer = (char *) alloca (buflen);
struct group resultbuf;
struct group *grp;
- uid_t oldeuid = 0;
-
- if (debug_level > 0)
- dbg_log (_("Haven't found \"%s\" in group cache!"), (char *)key);
+ bool use_malloc = false;
+ int errval = 0;
- if (secure[grpdb])
+ if (__builtin_expect (debug_level > 0, 0))
{
- oldeuid = geteuid ();
- seteuid (uid);
+ if (he == NULL)
+ dbg_log (_("Haven't found \"%s\" in group cache!"), keystr);
+ else
+ dbg_log (_("Reloading \"%s\" in group cache!"), keystr);
}
- while (__getgrnam_r (key, &resultbuf, buffer, buflen, &grp) != 0
- && errno == ERANGE)
+ while (lookup (req->type, key, &resultbuf, buffer, buflen, &grp) != 0
+ && (errval = errno) == ERANGE)
{
errno = 0;
- buflen += 256;
- buffer = alloca (buflen);
+
+ if (__builtin_expect (buflen > 32768, 0))
+ {
+ char *old_buffer = buffer;
+ buflen *= 2;
+ buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
+ if (buffer == NULL)
+ {
+ /* We ran out of memory. We cannot do anything but
+ sending a negative response. In reality this should
+ never happen. */
+ grp = NULL;
+ buffer = old_buffer;
+
+ /* We set the error to indicate this is (possibly) a
+ temporary error and that it does not mean the entry
+ is not available at all. */
+ errval = EAGAIN;
+ break;
+ }
+ use_malloc = true;
+ }
+ else
+ /* Allocate a new buffer on the stack. If possible combine it
+ with the previously allocated buffer. */
+ buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
}
- if (secure[grpdb])
- seteuid (oldeuid);
+ time_t timeout = cache_addgr (db, fd, req, keystr, grp, uid, he, dh, errval);
+
+ if (use_malloc)
+ free (buffer);
+
+ return timeout;
+}
+
+
+void
+addgrbyname (struct database_dyn *db, int fd, request_header *req,
+ void *key, uid_t uid)
+{
+ union keytype u = { .v = key };
+
+ addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
+}
+
+
+time_t
+readdgrbyname (struct database_dyn *db, struct hashentry *he,
+ struct datahead *dh)
+{
+ request_header req =
+ {
+ .type = GETGRBYNAME,
+ .key_len = he->len
+ };
+ union keytype u = { .v = db->data + he->key };
- cache_addgr (db, fd, req, key, grp, uid);
+ return addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
}
void
-addgrbygid (struct database *db, int fd, request_header *req,
+addgrbygid (struct database_dyn *db, int fd, request_header *req,
void *key, uid_t uid)
{
- /* Search for the entry matching the key. Please note that we don't
- look again in the table whether the dataset is now available. We
- simply insert it. It does not matter if it is in there twice. The
- pruning function only will look at the timestamp. */
- int buflen = 256;
- char *buffer = alloca (buflen);
- struct group resultbuf;
- struct group *grp;
- uid_t oldeuid = 0;
char *ep;
- gid_t gid = strtoul ((char *)key, &ep, 10);
-
- if (*(char*)key == '\0' || *ep != '\0') /* invalid numeric gid */
+ gid_t gid = strtoul ((char *) key, &ep, 10);
+
+ if (*(char *) key == '\0' || *ep != '\0') /* invalid numeric uid */
{
if (debug_level > 0)
- dbg_log (_("Invalid numeric gid \"%s\"!"), (char *)key);
+ dbg_log (_("Invalid numeric gid \"%s\"!"), (char *) key);
errno = EINVAL;
return;
}
- if (debug_level > 0)
- dbg_log (_("Haven't found \"%d\" in group cache!"), gid);
+ union keytype u = { .g = gid };
- if (secure[grpdb])
- {
- oldeuid = geteuid ();
- seteuid (uid);
- }
+ addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
+}
- while (__getgrgid_r (gid, &resultbuf, buffer, buflen, &grp) != 0
- && errno == ERANGE)
- {
- errno = 0;
- buflen += 256;
- buffer = alloca (buflen);
- }
- if (secure[grpdb])
- seteuid (oldeuid);
+time_t
+readdgrbygid (struct database_dyn *db, struct hashentry *he,
+ struct datahead *dh)
+{
+ char *ep;
+ gid_t gid = strtoul (db->data + he->key, &ep, 10);
+
+ /* Since the key has been added before it must be OK. */
+ assert (*(db->data + he->key) != '\0' && *ep == '\0');
+
+ request_header req =
+ {
+ .type = GETGRBYGID,
+ .key_len = he->len
+ };
+ union keytype u = { .g = gid };
- cache_addgr (db, fd, req, key, grp, uid);
+ return addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
}
projects / platform / upstream / glibc.git / blobdiff