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authorFlorian Weimer <fweimer@redhat.com>2017-11-23 14:08:11 +0100
committerFlorian Weimer <fweimer@redhat.com>2017-11-23 14:08:11 +0100
commit67f36c7922fe5053549ec9aa7f60ed2c5c2d65b4 (patch)
treec078a7a50a890570e7c8eb24bf9f81fa45409bcc /nss
parentsigwait: Do not fail with EINTR and return error code [BZ #22478] (diff)
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nss: Export nscd hash function as __nss_hash [BZ #22459]
Diffstat (limited to 'nss')
-rw-r--r--nss/Makefile2
-rw-r--r--nss/Versions1
-rw-r--r--nss/nss_hash.c79
3 files changed, 81 insertions, 1 deletions
diff --git a/nss/Makefile b/nss/Makefile
index 26952112c1..f9ecea56a0 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -28,7 +28,7 @@ headers := nss.h
routines = nsswitch getnssent getnssent_r digits_dots \
valid_field valid_list_field rewrite_field \
$(addsuffix -lookup,$(databases)) \
- compat-lookup
+ compat-lookup nss_hash
# These are the databases that go through nss dispatch.
# Caution: if you add a database here, you must add its real name
diff --git a/nss/Versions b/nss/Versions
index 7694998f1d..db8c887720 100644
--- a/nss/Versions
+++ b/nss/Versions
@@ -15,6 +15,7 @@ libc {
__nss_passwd_lookup2; __nss_group_lookup2; __nss_hosts_lookup2;
__nss_services_lookup2; __nss_next2; __nss_lookup;
+ __nss_hash;
}
}
diff --git a/nss/nss_hash.c b/nss/nss_hash.c
new file mode 100644
index 0000000000..5fb837a381
--- /dev/null
+++ b/nss/nss_hash.c
@@ -0,0 +1,79 @@
+/* Copyright (c) 1997-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Thorsten Kukuk <kukuk@suse.de>, 1997.
+
+ 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.
+
+ The GNU C Library 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.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <nss.h>
+
+/* This is from libc/db/hash/hash_func.c, hash3 is static there */
+/*
+ * This is INCREDIBLY ugly, but fast. We break the string up into 8 byte
+ * units. On the first time through the loop we get the "leftover bytes"
+ * (strlen % 8). On every other iteration, we perform 8 HASHC's so we handle
+ * all 8 bytes. Essentially, this saves us 7 cmp & branch instructions. If
+ * this routine is heavily used enough, it's worth the ugly coding.
+ *
+ * OZ's original sdbm hash
+ */
+uint32_t
+__nss_hash (const void *keyarg, size_t len)
+{
+ const unsigned char *key;
+ size_t loop;
+ uint32_t h;
+
+#define HASHC h = *key++ + 65599 * h
+
+ h = 0;
+ key = keyarg;
+ if (len > 0)
+ {
+ loop = (len + 8 - 1) >> 3;
+ switch (len & (8 - 1))
+ {
+ case 0:
+ do
+ {
+ HASHC;
+ /* FALLTHROUGH */
+ case 7:
+ HASHC;
+ /* FALLTHROUGH */
+ case 6:
+ HASHC;
+ /* FALLTHROUGH */
+ case 5:
+ HASHC;
+ /* FALLTHROUGH */
+ case 4:
+ HASHC;
+ /* FALLTHROUGH */
+ case 3:
+ HASHC;
+ /* FALLTHROUGH */
+ case 2:
+ HASHC;
+ /* FALLTHROUGH */
+ case 1:
+ HASHC;
+ }
+ while (--loop);
+ }
+ }
+ return h;
+}
+
+libc_hidden_def (__nss_hash)