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authorUlrich Drepper <drepper@redhat.com>2007-10-13 18:14:58 +0000
committerUlrich Drepper <drepper@redhat.com>2007-10-13 18:14:58 +0000
commit43d3e6bd9210fc5900734206ed9478067b3f8003 (patch)
treedc2bbcd631158c54e6df632cb0ccaa643505a8ab /nscd
parentf7140274a410838336adca1acb40f5a862e6cac9 (diff)
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* nscd/nscd_getgr_r.c (nscd_getgr_r): Optimize a bit: use simpler
read mechanism when there are no group members and avoid no-op read syscall in this case.
Diffstat (limited to 'nscd')
-rw-r--r--nscd/nscd_getgr_r.c102
1 files changed, 59 insertions, 43 deletions
diff --git a/nscd/nscd_getgr_r.c b/nscd/nscd_getgr_r.c
index fc036f2..543ee17 100644
--- a/nscd/nscd_getgr_r.c
+++ b/nscd/nscd_getgr_r.c
@@ -190,26 +190,37 @@ nscd_getgr_r (const char *key, size_t keylen, request_type type,
/* Read the length information, group name, and password. */
if (gr_name == NULL)
{
- /* Allocate array to store lengths. */
- if (lensize == 0)
+ /* Handle a simple, usual case: no group members. */
+ if (__builtin_expect (gr_resp.gr_mem_cnt == 0, 1))
{
- lensize = gr_resp.gr_mem_cnt * sizeof (uint32_t);
- len = (uint32_t *) alloca (lensize);
+ size_t n = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
+ if (__builtin_expect (__readall (sock, resultbuf->gr_name, n)
+ != (ssize_t) n, 0))
+ goto out_close;
+ }
+ else
+ {
+ /* Allocate array to store lengths. */
+ if (lensize == 0)
+ {
+ lensize = gr_resp.gr_mem_cnt * sizeof (uint32_t);
+ len = (uint32_t *) alloca (lensize);
+ }
+ else if (gr_resp.gr_mem_cnt * sizeof (uint32_t) > lensize)
+ len = extend_alloca (len, lensize,
+ gr_resp.gr_mem_cnt * sizeof (uint32_t));
+
+ vec[0].iov_base = (void *) len;
+ vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t);
+ vec[1].iov_base = resultbuf->gr_name;
+ vec[1].iov_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
+ total_len = vec[0].iov_len + vec[1].iov_len;
+
+ /* Get this data. */
+ size_t n = __readvall (sock, vec, 2);
+ if (__builtin_expect (n != total_len, 0))
+ goto out_close;
}
- else if (gr_resp.gr_mem_cnt * sizeof (uint32_t) > lensize)
- len = extend_alloca (len, lensize,
- gr_resp.gr_mem_cnt * sizeof (uint32_t));
-
- vec[0].iov_base = (void *) len;
- vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t);
- vec[1].iov_base = resultbuf->gr_name;
- vec[1].iov_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
- total_len = vec[0].iov_len + vec[1].iov_len;
-
- /* Get this data. */
- size_t n = __readvall (sock, vec, 2);
- if (__builtin_expect (n != total_len, 0))
- goto out_close;
}
else
/* We already have the data. Just copy the group name and
@@ -251,37 +262,42 @@ nscd_getgr_r (const char *key, size_t keylen, request_type type,
}
retval = 0;
- if (gr_name == NULL)
+
+ /* If there are no group members TOTAL_LEN is zero. */
+ if (total_len > 0)
{
- size_t n = __readall (sock, resultbuf->gr_mem[0], total_len);
- if (__builtin_expect (n != total_len, 0))
+ if (gr_name == NULL)
{
- /* The `errno' to some value != ERANGE. */
- __set_errno (ENOENT);
- retval = ENOENT;
+ size_t n = __readall (sock, resultbuf->gr_mem[0], total_len);
+ if (__builtin_expect (n != total_len, 0))
+ {
+ /* The `errno' to some value != ERANGE. */
+ __set_errno (ENOENT);
+ retval = ENOENT;
+ }
+ else
+ *result = resultbuf;
}
else
- *result = resultbuf;
- }
- else
- {
- /* Copy the group member names. */
- memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
-
- /* Try to detect corrupt databases. */
- if (resultbuf->gr_name[gr_name_len - 1] != '\0'
- || resultbuf->gr_passwd[gr_resp.gr_passwd_len - 1] != '\0'
- || ({for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
- if (resultbuf->gr_mem[cnt][len[cnt] - 1] != '\0')
- break;
- cnt < gr_resp.gr_mem_cnt; }))
{
- /* We cannot use the database. */
- retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
- goto out_close;
+ /* Copy the group member names. */
+ memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
+
+ /* Try to detect corrupt databases. */
+ if (resultbuf->gr_name[gr_name_len - 1] != '\0'
+ || resultbuf->gr_passwd[gr_resp.gr_passwd_len - 1] != '\0'
+ || ({for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
+ if (resultbuf->gr_mem[cnt][len[cnt] - 1] != '\0')
+ break;
+ cnt < gr_resp.gr_mem_cnt; }))
+ {
+ /* We cannot use the database. */
+ retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
+ goto out_close;
+ }
+
+ *result = resultbuf;
}
-
- *result = resultbuf;
}
}
else