2005-07-13 Ulrich Drepper <drepper@redhat.com>

	* nscd/nscd_helper.c: Add a few __builtin_expect.
	[BZ #1080]
	* nscd/connections.c (send_ro_fd): Make sure BUF is aligned correctly.
	* nscd/nscd_helper.c (wait_on_socket): New function.
	(get_mapping): Use wait_on_socket instead of poll.  The former handles
	EINTR of poll correctly.
	(__nscd_open_socket): Likewise.
	(get_mapping): Make sure BUF is aligned correctly.
	(get_mapping): Use munmap on correct pointer.

diff --git a/nscd/nscd_helper.c b/nscd/nscd_helper.c
index b7f0239a23ecc65d974e5e2a9de9e2e0ab2011e2..5ea139ad70d069dd77cabf2538cd5dbde042013a 100644 (file)
--- a/nscd/nscd_helper.c
+++ b/nscd/nscd_helper.c
@@ -26,6 +26,7 @@
 #include <sys/poll.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 #include <sys/uio.h>
 #include <sys/un.h>
 #include <not-cancel.h>
@@ -135,6 +136,36 @@ __nscd_unmap (struct mapped_database *mapped)
 }
 
 
+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 *
@@ -166,8 +197,8 @@ get_mapping (request_type type, const char *key,
   iov[1].iov_base = (void *) key;
   iov[1].iov_len = keylen;
 
-  if (TEMP_FAILURE_RETRY (__writev (sock, iov, 2))
-      != iov[0].iov_len + iov[1].iov_len)
+  if (__builtin_expect (TEMP_FAILURE_RETRY (__writev (sock, iov, 2))
+                       != iov[0].iov_len + iov[1].iov_len, 0))
     /* We cannot even write the request.  */
     goto out_close2;
 
@@ -176,73 +207,80 @@ get_mapping (request_type type, const char *key,
   iov[0].iov_base = resdata;
   iov[0].iov_len = keylen;
 
-  char buf[CMSG_SPACE (sizeof (int))];
+  union
+  {
+    struct cmsghdr hdr;
+    char bytes[CMSG_SPACE (sizeof (int))];
+  } buf;
   struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 1,
-                       .msg_control = buf, .msg_controllen = sizeof (buf) };
+                       .msg_control = buf.bytes,
+                       .msg_controllen = sizeof (buf) };
   struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);
 
   cmsg->cmsg_level = SOL_SOCKET;
   cmsg->cmsg_type = SCM_RIGHTS;
   cmsg->cmsg_len = CMSG_LEN (sizeof (int));
 
+  /* This access is well-aligned since BUF is correctly aligned for an
+     int and CMSG_DATA preserves this alignment.  */
   *(int *) CMSG_DATA (cmsg) = -1;
 
   msg.msg_controllen = cmsg->cmsg_len;
 
-  struct pollfd fds[1];
-  fds[0].fd = sock;
-  fds[0].events = POLLIN | POLLERR | POLLHUP;
-  if (__poll (fds, 1, 5 * 1000) <= 0)
-    /* Failure or timeout.  */
+  if (wait_on_socket (sock) <= 0)
     goto out_close2;
 
 #ifndef MSG_NOSIGNAL
 # define MSG_NOSIGNAL 0
 #endif
-  if (TEMP_FAILURE_RETRY (__recvmsg (sock, &msg, MSG_NOSIGNAL)) != keylen)
+  if (__builtin_expect (TEMP_FAILURE_RETRY (__recvmsg (sock, &msg,
+                                                      MSG_NOSIGNAL))
+                       != keylen, 0))
     goto out_close2;
 
   mapfd = *(int *) CMSG_DATA (cmsg);
 
-  if (CMSG_FIRSTHDR (&msg)->cmsg_len != CMSG_LEN (sizeof (int)))
+  if (__builtin_expect (CMSG_FIRSTHDR (&msg)->cmsg_len
+                       != CMSG_LEN (sizeof (int)), 0))
     goto out_close;
 
   struct stat64 st;
-  if (strcmp (resdata, key) != 0
-      || fstat64 (mapfd, &st) != 0
-      || st.st_size < sizeof (struct database_pers_head))
+  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;
 
   struct database_pers_head head;
-  if (TEMP_FAILURE_RETRY (__pread (mapfd, &head, sizeof (head), 0))
-      != sizeof (head))
+  if (__builtin_expect (TEMP_FAILURE_RETRY (__pread (mapfd, &head,
+                                                    sizeof (head), 0))
+                       != sizeof (head), 0))
     goto out_close;
 
-  if (head.version != DB_VERSION || head.header_size != sizeof (head)
+  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.  */
-      || (! head.nscd_certainly_running
-         && head.timestamp + MAPPING_TIMEOUT < time (NULL)))
+      || __builtin_expect (! head.nscd_certainly_running
+                          && head.timestamp + MAPPING_TIMEOUT < time (NULL),
+                          0))
     goto out_close;
 
   size_t size = (sizeof (head) + roundup (head.module * sizeof (ref_t), ALIGN)
                 + head.data_size);
 
-  if (st.st_size < size)
+  if (__builtin_expect (st.st_size < size, 0))
     goto out_close;
 
   /* The file is large enough, map it now.  */
   void *mapping = __mmap (NULL, size, PROT_READ, MAP_SHARED, mapfd, 0);
-  if (mapping != MAP_FAILED)
+  if (__builtin_expect (mapping != MAP_FAILED, 1))
     {
       /* Allocate a record for the mapping.  */
-      struct mapped_database *newp;
-
-      newp = malloc (sizeof (*newp));
+      struct mapped_database *newp = malloc (sizeof (*newp));
       if (newp == NULL)
        {
          /* Ugh, after all we went through the memory allocation failed.  */
-         __munmap (result, size);
+         __munmap (mapping, size);
          goto out_close;
        }
 
@@ -372,19 +410,13 @@ __nscd_open_socket (const char *key, size_t keylen, request_type type,
       vec[1].iov_len = keylen;
 
       ssize_t nbytes = TEMP_FAILURE_RETRY (__writev (sock, vec, 2));
-      if (nbytes == (ssize_t) (sizeof (request_header) + keylen))
-       {
+      if (nbytes == (ssize_t) (sizeof (request_header) + keylen)
          /* Wait for data.  */
-         struct pollfd fds[1];
-         fds[0].fd = sock;
-         fds[0].events = POLLIN | POLLERR | POLLHUP;
-         if (__poll (fds, 1, 5 * 1000) > 0)
-           {
-             nbytes = TEMP_FAILURE_RETRY (__read (sock, response,
-                                                  responselen));
-             if (nbytes == (ssize_t) responselen)
-               return sock;
-           }
+         && wait_on_socket (sock) > 0)
+       {
+         nbytes = TEMP_FAILURE_RETRY (__read (sock, response, responselen));
+         if (nbytes == (ssize_t) responselen)
+           return sock;
        }
 
       close_not_cancel_no_status (sock);