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resolver: abuse _res a little less

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In the past, _res was a global variable.  Now, it's multiple function calls.
Several functions in the resolver use _res multiple times and therefore
call the function(s) far more than necessary.

Fix those callers to store the result of _res in a local variable.

Add __noinline to the definition of res_init() to avoid the code bloat
that these changes would have otherwise incurred.  Thanks to jilles
for noticing this.

Reviewed by:	jilles
MFC after:	1 week
Sponsored by:	Dell Inc.
Differential Revision:	https://reviews.freebsd.org/D3887
This commit is contained in:
Eric van Gyzen 2015-10-23 15:56:17 +00:00
parent ee74891fc7
commit 4cf0f1f5b3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=289837
1 changed files with 51 additions and 38 deletions
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89
lib/libc/resolv/res_data.c
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@ -77,9 +77,10 @@ const char *_res_sectioncodes[] = {
int res_ourserver_p(const res_state, const struct sockaddr_in *);
int
__noinline int
res_init(void) {
extern int __res_vinit(res_state, int);
res_state statp = &_res;
/*
* These three fields used to be statically initialized. This made
@ -100,14 +101,14 @@ res_init(void) {
* set in RES_DEFAULT). Our solution is to declare such applications
* "broken". They could fool us by setting RES_INIT but none do (yet).
*/
if (!_res.retrans)
_res.retrans = RES_TIMEOUT;
if (!_res.retry)
_res.retry = RES_DFLRETRY;
if (!(_res.options & RES_INIT))
_res.options = RES_DEFAULT;
if (!statp->retrans)
statp->retrans = RES_TIMEOUT;
if (!statp->retry)
statp->retry = RES_DFLRETRY;
if (!(statp->options & RES_INIT))
statp->options = RES_DEFAULT;
return (__res_vinit(&_res, 1));
return (__res_vinit(statp, 1));
}
void
@ -122,10 +123,11 @@ fp_query(const u_char *msg, FILE *file) {
void
fp_nquery(const u_char *msg, int len, FILE *file) {
if ((_res.options & RES_INIT) == 0U && res_init() == -1)
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1)
return;
res_pquery(&_res, msg, len, file);
res_pquery(statp, msg, len, file);
}
int
@ -138,23 +140,25 @@ res_mkquery(int op, /*!< opcode of query */
u_char *buf, /*!< buffer to put query */
int buflen) /*!< size of buffer */
{
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(&_res, NETDB_INTERNAL);
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
return (-1);
}
return (res_nmkquery(&_res, op, dname, class, type,
return (res_nmkquery(statp, op, dname, class, type,
data, datalen,
newrr_in, buf, buflen));
}
int
res_mkupdate(ns_updrec *rrecp_in, u_char *buf, int buflen) {
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(&_res, NETDB_INTERNAL);
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
return (-1);
}
return (res_nmkupdate(&_res, rrecp_in, buf, buflen));
return (res_nmkupdate(statp, rrecp_in, buf, buflen));
}
int
@ -163,11 +167,12 @@ res_query(const char *name, /*!< domain name */
u_char *answer, /*!< buffer to put answer */
int anslen) /*!< size of answer buffer */
{
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(&_res, NETDB_INTERNAL);
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
return (-1);
}
return (res_nquery(&_res, name, class, type, answer, anslen));
return (res_nquery(statp, name, class, type, answer, anslen));
}
#ifndef _LIBC
@ -189,12 +194,13 @@ res_isourserver(const struct sockaddr_in *inp) {
int
res_send(const u_char *buf, int buflen, u_char *ans, int anssiz) {
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
/* errno should have been set by res_init() in this case. */
return (-1);
}
return (res_nsend(&_res, buf, buflen, ans, anssiz));
return (res_nsend(statp, buf, buflen, ans, anssiz));
}
#ifndef _LIBC
@ -202,12 +208,13 @@ int
res_sendsigned(const u_char *buf, int buflen, ns_tsig_key *key,
u_char *ans, int anssiz)
{
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
/* errno should have been set by res_init() in this case. */
return (-1);
}
return (res_nsendsigned(&_res, buf, buflen, key, ans, anssiz));
return (res_nsendsigned(statp, buf, buflen, key, ans, anssiz));
}
#endif
@ -218,12 +225,13 @@ res_close(void) {
int
res_update(ns_updrec *rrecp_in) {
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(&_res, NETDB_INTERNAL);
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
return (-1);
}
return (res_nupdate(&_res, rrecp_in, NULL));
return (res_nupdate(statp, rrecp_in, NULL));
}
int
@ -232,12 +240,13 @@ res_search(const char *name, /*!< domain name */
u_char *answer, /*!< buffer to put answer */
int anslen) /*!< size of answer */
{
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(&_res, NETDB_INTERNAL);
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
return (-1);
}
return (res_nsearch(&_res, name, class, type, answer, anslen));
return (res_nsearch(statp, name, class, type, answer, anslen));
}
int
@ -247,24 +256,26 @@ res_querydomain(const char *name,
u_char *answer, /*!< buffer to put answer */
int anslen) /*!< size of answer */
{
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(&_res, NETDB_INTERNAL);
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
return (-1);
}
return (res_nquerydomain(&_res, name, domain,
return (res_nquerydomain(statp, name, domain,
class, type,
answer, anslen));
}
u_int
res_randomid(void) {
if ((_res.options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(&_res, NETDB_INTERNAL);
res_state statp = &_res;
if ((statp->options & RES_INIT) == 0U && res_init() == -1) {
RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
return (-1);
}
return (res_nrandomid(&_res));
return (res_nrandomid(statp));
}
int
@ -284,13 +295,15 @@ hostalias(const char *name) {
int
local_hostname_length(const char *hostname) {
int len_host, len_domain;
res_state statp;
if (!*_res.defdname)
statp = &_res;
if (!*statp->defdname)
res_init();
len_host = strlen(hostname);
len_domain = strlen(_res.defdname);
len_domain = strlen(statp->defdname);
if (len_host > len_domain &&
!strcasecmp(hostname + len_host - len_domain, _res.defdname) &&
!strcasecmp(hostname + len_host - len_domain, statp->defdname) &&
hostname[len_host - len_domain - 1] == '.')
return (len_host - len_domain - 1);
return (0);