-/* Copyright (C) 1998-2002,2003,2004,2005,2006,2007
- Free Software Foundation, Inc.
+/* Copyright (C) 1998-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
Lesser 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. */
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
+#include <stdint.h>
#include <sys/mman.h>
+#include <sys/param.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <not-cancel.h>
-#include <nis/rpcsvc/nis.h>
+#include <kernel-features.h>
+#include <nss.h>
#include "nscd-client.h"
+/* Extra time we wait if the socket is still receiving data. This
+ value is in milliseconds. Note that the other side is nscd on the
+ local machine and it is already transmitting data. So the wait
+ time need not be long. */
+#define EXTRA_RECEIVE_TIME 200
+
+
+static int
+wait_on_socket (int sock, long int usectmo)
+{
+ struct pollfd fds[1];
+ fds[0].fd = sock;
+ fds[0].events = POLLIN | POLLERR | POLLHUP;
+ int n = __poll (fds, 1, usectmo);
+ if (n == -1 && __builtin_expect (errno == EINTR, 0))
+ {
+ /* Handle the case where the poll() call is interrupted by a
+ signal. We cannot just use TEMP_FAILURE_RETRY since it might
+ lead to infinite loops. */
+ struct timeval now;
+ (void) __gettimeofday (&now, NULL);
+ long int end = now.tv_sec * 1000 + usectmo + (now.tv_usec + 500) / 1000;
+ long int timeout = usectmo;
+ while (1)
+ {
+ n = __poll (fds, 1, timeout);
+ if (n != -1 || errno != EINTR)
+ break;
+
+ /* Recompute the timeout time. */
+ (void) __gettimeofday (&now, NULL);
+ timeout = end - (now.tv_sec * 1000 + (now.tv_usec + 500) / 1000);
+ }
+ }
+
+ return n;
+}
+
ssize_t
__readall (int fd, void *buf, size_t len)
ssize_t ret;
do
{
+ again:
ret = TEMP_FAILURE_RETRY (__read (fd, buf, n));
if (ret <= 0)
- break;
+ {
+ if (__builtin_expect (ret < 0 && errno == EAGAIN, 0)
+ /* The socket is still receiving data. Wait a bit more. */
+ && wait_on_socket (fd, EXTRA_RECEIVE_TIME) > 0)
+ goto again;
+
+ break;
+ }
buf = (char *) buf + ret;
n -= ret;
}
{
ssize_t ret = TEMP_FAILURE_RETRY (__readv (fd, iov, iovcnt));
if (ret <= 0)
- return ret;
+ {
+ if (__glibc_likely (ret == 0 || errno != EAGAIN))
+ /* A genuine error or no data to read. */
+ return ret;
+
+ /* The data has not all yet been received. Do as if we have not
+ read anything yet. */
+ ret = 0;
+ }
size_t total = 0;
for (int i = 0; i < iovcnt; ++i)
}
iovp->iov_base = (char *) iovp->iov_base + r;
iovp->iov_len -= r;
+ again:
r = TEMP_FAILURE_RETRY (__readv (fd, iovp, iovcnt));
if (r <= 0)
- break;
+ {
+ if (__builtin_expect (r < 0 && errno == EAGAIN, 0)
+ /* The socket is still receiving data. Wait a bit more. */
+ && wait_on_socket (fd, EXTRA_RECEIVE_TIME) > 0)
+ goto again;
+
+ break;
+ }
ret += r;
}
while (ret < total);
static int
open_socket (request_type type, const char *key, size_t keylen)
{
- int sock = __socket (PF_UNIX, SOCK_STREAM, 0);
+ int sock;
+
+ sock = __socket (PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
if (sock < 0)
return -1;
+ size_t real_sizeof_reqdata = sizeof (request_header) + keylen;
struct
{
request_header req;
- char key[keylen];
- } reqdata;
- size_t real_sizeof_reqdata = sizeof (request_header) + keylen;
-
- /* Make socket non-blocking. */
- __fcntl (sock, F_SETFL, O_RDWR | O_NONBLOCK);
+ char key[];
+ } *reqdata = alloca (real_sizeof_reqdata);
struct sockaddr_un sun;
sun.sun_family = AF_UNIX;
&& errno != EINPROGRESS)
goto out;
- reqdata.req.version = NSCD_VERSION;
- reqdata.req.type = type;
- reqdata.req.key_len = keylen;
+ reqdata->req.version = NSCD_VERSION;
+ reqdata->req.type = type;
+ reqdata->req.key_len = keylen;
- memcpy (reqdata.key, key, keylen);
+ memcpy (reqdata->key, key, keylen);
bool first_try = true;
struct timeval tvend;
#ifndef MSG_NOSIGNAL
# define MSG_NOSIGNAL 0
#endif
- ssize_t wres = TEMP_FAILURE_RETRY (__send (sock, &reqdata,
+ ssize_t wres = TEMP_FAILURE_RETRY (__send (sock, reqdata,
real_sizeof_reqdata,
MSG_NOSIGNAL));
- if (__builtin_expect (wres == (ssize_t) real_sizeof_reqdata, 1))
+ if (__glibc_likely (wres == (ssize_t) real_sizeof_reqdata))
/* We managed to send the request. */
return sock;
}
out:
- close_not_cancel_no_status (sock);
+ __close_nocancel_nostatus (sock);
return -1;
}
}
-static int
-wait_on_socket (int sock)
-{
- struct pollfd fds[1];
- fds[0].fd = sock;
- fds[0].events = POLLIN | POLLERR | POLLHUP;
- int n = __poll (fds, 1, 5 * 1000);
- if (n == -1 && __builtin_expect (errno == EINTR, 0))
- {
- /* Handle the case where the poll() call is interrupted by a
- signal. We cannot just use TEMP_FAILURE_RETRY since it might
- lead to infinite loops. */
- struct timeval now;
- (void) __gettimeofday (&now, NULL);
- long int end = (now.tv_sec + 5) * 1000 + (now.tv_usec + 500) / 1000;
- while (1)
- {
- long int timeout = end - (now.tv_sec * 1000
- + (now.tv_usec + 500) / 1000);
- n = __poll (fds, 1, timeout);
- if (n != -1 || errno != EINTR)
- break;
- (void) __gettimeofday (&now, NULL);
- }
- }
-
- return n;
-}
-
-
/* Try to get a file descriptor for the shared meory segment
containing the database. */
-static struct mapped_database *
-get_mapping (request_type type, const char *key,
- struct mapped_database **mappedp)
+struct mapped_database *
+__nscd_get_mapping (request_type type, const char *key,
+ struct mapped_database **mappedp)
{
struct mapped_database *result = NO_MAPPING;
#ifdef SCM_RIGHTS
/* Room for the data sent along with the file descriptor. We expect
the key name back. */
- struct iovec iov[1];
+ uint64_t mapsize;
+ struct iovec iov[2];
iov[0].iov_base = resdata;
iov[0].iov_len = keylen;
+ iov[1].iov_base = &mapsize;
+ iov[1].iov_len = sizeof (mapsize);
union
{
struct cmsghdr hdr;
char bytes[CMSG_SPACE (sizeof (int))];
} buf;
- struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 1,
+ struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 2,
.msg_control = buf.bytes,
.msg_controllen = sizeof (buf) };
struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);
/* This access is well-aligned since BUF is correctly aligned for an
int and CMSG_DATA preserves this alignment. */
- *(int *) CMSG_DATA (cmsg) = -1;
+ memset (CMSG_DATA (cmsg), '\xff', sizeof (int));
msg.msg_controllen = cmsg->cmsg_len;
- if (wait_on_socket (sock) <= 0)
+ if (wait_on_socket (sock, 5 * 1000) <= 0)
goto out_close2;
# ifndef MSG_CMSG_CLOEXEC
# define MSG_CMSG_CLOEXEC 0
# endif
- if (__builtin_expect (TEMP_FAILURE_RETRY (__recvmsg (sock, &msg,
- MSG_CMSG_CLOEXEC))
- != keylen, 0))
- goto out_close2;
+ ssize_t n = TEMP_FAILURE_RETRY (__recvmsg (sock, &msg, MSG_CMSG_CLOEXEC));
if (__builtin_expect (CMSG_FIRSTHDR (&msg) == NULL
|| (CMSG_FIRSTHDR (&msg)->cmsg_len
!= CMSG_LEN (sizeof (int))), 0))
goto out_close2;
- mapfd = *(int *) CMSG_DATA (cmsg);
-
- struct stat64 st;
- if (__builtin_expect (strcmp (resdata, key) != 0, 0)
- || __builtin_expect (fstat64 (mapfd, &st) != 0, 0)
- || __builtin_expect (st.st_size < sizeof (struct database_pers_head), 0))
- goto out_close;
+ int *ip = (void *) CMSG_DATA (cmsg);
+ mapfd = *ip;
- struct database_pers_head head;
- if (__builtin_expect (TEMP_FAILURE_RETRY (__pread (mapfd, &head,
- sizeof (head), 0))
- != sizeof (head), 0))
+ if (__glibc_unlikely (n != keylen && n != keylen + sizeof (mapsize)))
goto out_close;
- if (__builtin_expect (head.version != DB_VERSION, 0)
- || __builtin_expect (head.header_size != sizeof (head), 0)
- /* This really should not happen but who knows, maybe the update
- thread got stuck. */
- || __builtin_expect (! head.nscd_certainly_running
- && head.timestamp + MAPPING_TIMEOUT < time (NULL),
- 0))
+ if (__glibc_unlikely (strcmp (resdata, key) != 0))
goto out_close;
- size_t size = (sizeof (head) + roundup (head.module * sizeof (ref_t), ALIGN)
- + head.data_size);
+ if (__glibc_unlikely (n == keylen))
+ {
+ struct stat64 st;
+ if (__builtin_expect (fstat64 (mapfd, &st) != 0, 0)
+ || __builtin_expect (st.st_size < sizeof (struct database_pers_head),
+ 0))
+ goto out_close;
- if (__builtin_expect (st.st_size < size, 0))
- goto out_close;
+ mapsize = st.st_size;
+ }
/* The file is large enough, map it now. */
- void *mapping = __mmap (NULL, size, PROT_READ, MAP_SHARED, mapfd, 0);
- if (__builtin_expect (mapping != MAP_FAILED, 1))
+ void *mapping = __mmap (NULL, mapsize, PROT_READ, MAP_SHARED, mapfd, 0);
+ if (__glibc_likely (mapping != MAP_FAILED))
{
- /* Allocate a record for the mapping. */
- struct mapped_database *newp = malloc (sizeof (*newp));
- if (newp == NULL)
+ /* Check whether the database is correct and up-to-date. */
+ struct database_pers_head *head = mapping;
+
+ if (__builtin_expect (head->version != DB_VERSION, 0)
+ || __builtin_expect (head->header_size != sizeof (*head), 0)
+ /* Catch some misconfiguration. The server should catch
+ them now but some older versions did not. */
+ || __builtin_expect (head->module == 0, 0)
+ /* This really should not happen but who knows, maybe the update
+ thread got stuck. */
+ || __builtin_expect (! head->nscd_certainly_running
+ && (head->timestamp + MAPPING_TIMEOUT
+ < time (NULL)), 0))
{
- /* Ugh, after all we went through the memory allocation failed. */
- __munmap (mapping, size);
+ out_unmap:
+ __munmap (mapping, mapsize);
goto out_close;
}
+ size_t size = (sizeof (*head) + roundup (head->module * sizeof (ref_t),
+ ALIGN)
+ + head->data_size);
+
+ if (__glibc_unlikely (mapsize < size))
+ goto out_unmap;
+
+ /* Allocate a record for the mapping. */
+ struct mapped_database *newp = malloc (sizeof (*newp));
+ if (newp == NULL)
+ /* Ugh, after all we went through the memory allocation failed. */
+ goto out_unmap;
+
newp->head = mapping;
- newp->data = ((char *) mapping + head.header_size
- + roundup (head.module * sizeof (ref_t), ALIGN));
+ newp->data = ((char *) mapping + head->header_size
+ + roundup (head->module * sizeof (ref_t), ALIGN));
newp->mapsize = size;
- newp->datasize = head.data_size;
+ newp->datasize = head->data_size;
/* Set counter to 1 to show it is usable. */
newp->counter = 1;
return result;
}
-
struct mapped_database *
__nscd_get_map_ref (request_type type, const char *name,
volatile struct locked_map_ptr *mapptr, int *gc_cyclep)
if (cur == NO_MAPPING)
return cur;
- int cnt = 0;
- while (__builtin_expect (atomic_compare_and_exchange_val_acq (&mapptr->lock,
- 1, 0) != 0, 0))
- {
- // XXX Best number of rounds?
- if (__builtin_expect (++cnt > 5, 0))
- return NO_MAPPING;
-
- atomic_delay ();
- }
+ if (!__nscd_acquire_maplock (mapptr))
+ return NO_MAPPING;
cur = mapptr->mapped;
- if (__builtin_expect (cur != NO_MAPPING, 1))
+ if (__glibc_likely (cur != NO_MAPPING))
{
/* If not mapped or timestamp not updated, request new map. */
if (cur == NULL
|| (cur->head->nscd_certainly_running == 0
&& cur->head->timestamp + MAPPING_TIMEOUT < time (NULL))
|| cur->head->data_size > cur->datasize)
- cur = get_mapping (type, name,
- (struct mapped_database **) &mapptr->mapped);
+ cur = __nscd_get_mapping (type, name,
+ (struct mapped_database **) &mapptr->mapped);
- if (__builtin_expect (cur != NO_MAPPING, 1))
+ if (__glibc_likely (cur != NO_MAPPING))
{
if (__builtin_expect (((*gc_cyclep = cur->head->gc_cycle) & 1) != 0,
0))
}
+/* Using sizeof (hashentry) is not always correct to determine the size of
+ the data structure as found in the nscd cache. The program could be
+ a 64-bit process and nscd could be a 32-bit process. In this case
+ sizeof (hashentry) would overestimate the size. The following is
+ the minimum size of such an entry, good enough for our tests here. */
+#define MINIMUM_HASHENTRY_SIZE \
+ (offsetof (struct hashentry, dellist) + sizeof (int32_t))
+
/* Don't return const struct datahead *, as eventhough the record
is normally constant, it can change arbitrarily during nscd
garbage collection. */
struct datahead *
__nscd_cache_search (request_type type, const char *key, size_t keylen,
- const struct mapped_database *mapped)
+ const struct mapped_database *mapped, size_t datalen)
{
- unsigned long int hash = __nis_hash (key, keylen) % mapped->head->module;
+ unsigned long int hash = __nss_hash (key, keylen) % mapped->head->module;
size_t datasize = mapped->datasize;
- ref_t work = mapped->head->array[hash];
- while (work != ENDREF && work + sizeof (struct hashentry) <= datasize)
+ ref_t trail = mapped->head->array[hash];
+ trail = atomic_forced_read (trail);
+ ref_t work = trail;
+ size_t loop_cnt = datasize / (MINIMUM_HASHENTRY_SIZE
+ + offsetof (struct datahead, data) / 2);
+ int tick = 0;
+
+ while (work != ENDREF && work + MINIMUM_HASHENTRY_SIZE <= datasize)
{
struct hashentry *here = (struct hashentry *) (mapped->data + work);
+ ref_t here_key, here_packet;
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
/* Although during garbage collection when moving struct hashentry
records around we first copy from old to new location and then
adjust pointer from previous hashentry to it, there is no barrier
if (type == here->type
&& keylen == here->len
- && here->key + keylen <= datasize
- && memcmp (key, mapped->data + here->key, keylen) == 0
- && here->packet + sizeof (struct datahead) <= datasize)
+ && (here_key = atomic_forced_read (here->key)) + keylen <= datasize
+ && memcmp (key, mapped->data + here_key, keylen) == 0
+ && ((here_packet = atomic_forced_read (here->packet))
+ + sizeof (struct datahead) <= datasize))
{
/* We found the entry. Increment the appropriate counter. */
struct datahead *dh
- = (struct datahead *) (mapped->data + here->packet);
+ = (struct datahead *) (mapped->data + here_packet);
-#ifndef _STRING_ARCH_unaligned
+#if !_STRING_ARCH_unaligned
if ((uintptr_t) dh & (__alignof__ (*dh) - 1))
return NULL;
#endif
/* See whether we must ignore the entry or whether something
is wrong because garbage collection is in progress. */
- if (dh->usable && here->packet + dh->allocsize <= datasize)
+ if (dh->usable
+ && here_packet + dh->allocsize <= datasize
+ && (here_packet + offsetof (struct datahead, data) + datalen
+ <= datasize))
return dh;
}
- work = here->next;
+ work = atomic_forced_read (here->next);
+ /* Prevent endless loops. This should never happen but perhaps
+ the database got corrupted, accidentally or deliberately. */
+ if (work == trail || loop_cnt-- == 0)
+ break;
+ if (tick)
+ {
+ struct hashentry *trailelem;
+ trailelem = (struct hashentry *) (mapped->data + trail);
+
+#if !_STRING_ARCH_unaligned
+ /* We have to redo the checks. Maybe the data changed. */
+ if ((uintptr_t) trailelem & (__alignof__ (*trailelem) - 1))
+ return NULL;
+#endif
+
+ if (trail + MINIMUM_HASHENTRY_SIZE > datasize)
+ return NULL;
+
+ trail = atomic_forced_read (trailelem->next);
+ }
+ tick = 1 - tick;
}
return NULL;
if (sock >= 0)
{
/* Wait for data. */
- if (wait_on_socket (sock) > 0)
+ if (wait_on_socket (sock, 5 * 1000) > 0)
{
ssize_t nbytes = TEMP_FAILURE_RETRY (__read (sock, response,
responselen));
return sock;
}
- close_not_cancel_no_status (sock);
+ __close_nocancel_nostatus (sock);
}
__set_errno (saved_errno);
projects / thirdparty / glibc.git / blobdiff