From 21038157e45f37d493c98fc886f3d2b16b74207b Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Mon, 18 Jul 2005 08:01:46 +0000 Subject: [PATCH] 2005-07-13 Ulrich Drepper * 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. --- nscd/nscd_helper.c | 106 +++++++++++++++++++++++++++++---------------- 1 file changed, 69 insertions(+), 37 deletions(-) diff --git a/nscd/nscd_helper.c b/nscd/nscd_helper.c index b7f0239a23..5ea139ad70 100644 --- a/nscd/nscd_helper.c +++ b/nscd/nscd_helper.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -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);