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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.
This commit is contained in:
Ulrich Drepper 2007-10-13 18:14:58 +00:00
parent f7140274a4
commit 43d3e6bd92
2 changed files with 61 additions and 41 deletions
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4
ChangeLog
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@ -1,5 +1,9 @@
2007-10-13 Ulrich Drepper <drepper@redhat.com> 2007-10-13 Ulrich Drepper <drepper@redhat.com>
* 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.
[BZ #3242] [BZ #3242]
* nscd/nscd_helper.c (wait_on_socket): Take timeout as parameter. * nscd/nscd_helper.c (wait_on_socket): Take timeout as parameter.
(__readall): If reading failed due to EAGAIN error wait a bit (__readall): If reading failed due to EAGAIN error wait a bit

98
nscd/nscd_getgr_r.c
View File

@ -190,26 +190,37 @@ nscd_getgr_r (const char *key, size_t keylen, request_type type,
/* Read the length information, group name, and password. */ /* Read the length information, group name, and password. */
if (gr_name == NULL) if (gr_name == NULL)
{ {
/* Allocate array to store lengths. */ /* Handle a simple, usual case: no group members. */
if (lensize == 0) if (__builtin_expect (gr_resp.gr_mem_cnt == 0, 1))
{ {
lensize = gr_resp.gr_mem_cnt * sizeof (uint32_t); size_t n = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
len = (uint32_t *) alloca (lensize); if (__builtin_expect (__readall (sock, resultbuf->gr_name, n)
!= (ssize_t) n, 0))
goto out_close;
} }
else if (gr_resp.gr_mem_cnt * sizeof (uint32_t) > lensize) else
len = extend_alloca (len, lensize, {
gr_resp.gr_mem_cnt * sizeof (uint32_t)); /* 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_base = (void *) len;
vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t); vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t);
vec[1].iov_base = resultbuf->gr_name; vec[1].iov_base = resultbuf->gr_name;
vec[1].iov_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len; vec[1].iov_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
total_len = vec[0].iov_len + vec[1].iov_len; total_len = vec[0].iov_len + vec[1].iov_len;
/* Get this data. */ /* Get this data. */
size_t n = __readvall (sock, vec, 2); size_t n = __readvall (sock, vec, 2);
if (__builtin_expect (n != total_len, 0)) if (__builtin_expect (n != total_len, 0))
goto out_close; goto out_close;
}
} }
else else
/* We already have the data. Just copy the group name and /* 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; 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 (gr_name == NULL)
if (__builtin_expect (n != total_len, 0))
{ {
/* The `errno' to some value != ERANGE. */ size_t n = __readall (sock, resultbuf->gr_mem[0], total_len);
__set_errno (ENOENT); if (__builtin_expect (n != total_len, 0))
retval = ENOENT; {
/* The `errno' to some value != ERANGE. */
__set_errno (ENOENT);
retval = ENOENT;
}
else
*result = resultbuf;
} }
else 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. */ /* Copy the group member names. */
retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1; memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
goto out_close;
}
*result = resultbuf; /* 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;
}
} }
} }
else else