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[PATCH] Properly check for short writes when sending the response in nscd
- From: Andreas Schwab <schwab at suse dot de>
- To: libc-alpha at sourceware dot org
- Date: Wed, 10 Apr 2013 12:31:29 +0200
- Subject: [PATCH] Properly check for short writes when sending the response in nscd
This fixes spurious short write messages in nscd. The response record
is only a part of the dataset structure, but total contains the size of
the complete structure, so it will never equal what is written as
response.
Andreas.
* nscd/grpcache.c (cache_addgr): Properly check for short write.
* nscd/initgrcache.c (addinitgroupsX): Likewise.
* nscd/pwdcache.c (cache_addpw): Likewise.
* nscd/servicescache.c (cache_addserv): Likewise. Don't write
more than recsize.
diff --git a/nscd/grpcache.c b/nscd/grpcache.c
index d25d8e9..eccb7b1 100644
--- a/nscd/grpcache.c
+++ b/nscd/grpcache.c
@@ -75,6 +75,7 @@ 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);
@@ -114,8 +115,12 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
total = sizeof (notfound);
if (fd != -1)
- written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
- MSG_NOSIGNAL));
+ {
+ written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
+ MSG_NOSIGNAL));
+ if (written != total)
+ all_written = false;
+ }
else
written = total;
@@ -342,6 +347,9 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
# endif
#endif
written = writeall (fd, &dataset->resp, dataset->head.recsize);
+
+ if (written != dataset->head.recsize)
+ all_written = false;
}
/* Add the record to the database. But only if it has not been
@@ -401,7 +409,7 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
}
}
- 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__,
diff --git a/nscd/initgrcache.c b/nscd/initgrcache.c
index 196407c8..6b0b26b 100644
--- a/nscd/initgrcache.c
+++ b/nscd/initgrcache.c
@@ -171,10 +171,12 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
nip = nip->next;
}
+ bool all_written;
ssize_t total;
ssize_t written;
time_t timeout;
out:
+ all_written = true;
timeout = MAX_TIMEOUT_VALUE;
if (!any_success)
{
@@ -198,8 +200,12 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
/* We have no data. This means we send the standard reply for this
case. */
if (fd != -1)
- written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
- MSG_NOSIGNAL));
+ {
+ written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
+ MSG_NOSIGNAL));
+ if (written != total)
+ all_written = false;
+ }
/* If we have a transient error or cannot permanently store
the result, so be it. */
@@ -379,6 +385,9 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
# endif
#endif
written = writeall (fd, &dataset->resp, dataset->head.recsize);
+
+ if (written != dataset->head.recsize)
+ all_written = false;
}
@@ -405,7 +414,7 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
free (groups);
- 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__,
diff --git a/nscd/pwdcache.c b/nscd/pwdcache.c
index ef492b5..aa82ead 100644
--- a/nscd/pwdcache.c
+++ b/nscd/pwdcache.c
@@ -81,6 +81,7 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
const void *key, struct passwd *pwd, 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);
@@ -120,8 +121,12 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
written = total = sizeof (notfound);
if (fd != -1)
- written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
- MSG_NOSIGNAL));
+ {
+ written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
+ MSG_NOSIGNAL));
+ if (written != total)
+ all_written = false;
+ }
/* If we have a transient error or cannot permanently store
the result, so be it. */
@@ -306,7 +311,7 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
+ db->head->data_size));
written = sendfileall (fd, db->wr_fd,
(char *) &dataset->resp
- - (char *) db->head, dataset->head.recsize );
+ - (char *) db->head, dataset->head.recsize);
# ifndef __ASSUME_SENDFILE
if (written == -1 && errno == ENOSYS)
goto use_write;
@@ -318,6 +323,9 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
# endif
#endif
written = writeall (fd, &dataset->resp, dataset->head.recsize);
+
+ if (written != dataset->head.recsize)
+ all_written = false;
}
@@ -377,7 +385,7 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
}
}
- 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__,
diff --git a/nscd/servicescache.c b/nscd/servicescache.c
index d29cde7..bdbc495 100644
--- a/nscd/servicescache.c
+++ b/nscd/servicescache.c
@@ -65,6 +65,7 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
const void *key, struct servent *serv, 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);
@@ -104,8 +105,12 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
written = total = sizeof (notfound);
if (fd != -1)
- written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
- MSG_NOSIGNAL));
+ {
+ written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
+ MSG_NOSIGNAL));
+ if (written != total)
+ all_written = false;
+ }
/* If we have a transient error or cannot permanently store
the result, so be it. */
@@ -290,14 +295,14 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
{
assert (db->wr_fd != -1);
assert ((char *) &dataset->resp > (char *) db->data);
- assert ((char *) &dataset->resp - (char *) db->head
+ assert ((char *) dataset - (char *) db->head
+ total
<= (sizeof (struct database_pers_head)
+ db->head->module * sizeof (ref_t)
+ db->head->data_size));
written = sendfileall (fd, db->wr_fd,
(char *) &dataset->resp
- - (char *) db->head, total);
+ - (char *) db->head, dataset->head.recsize);
# ifndef __ASSUME_SENDFILE
if (written == -1 && errno == ENOSYS)
goto use_write;
@@ -308,7 +313,10 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
use_write:
# endif
#endif
- written = writeall (fd, &dataset->resp, total);
+ written = writeall (fd, &dataset->resp, dataset->head.recsize);
+
+ if (written != dataset->head.recsize)
+ all_written = false;
}
/* Add the record to the database. But only if it has not been
@@ -332,7 +340,7 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
}
}
- 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__,
--
1.8.2.1
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."