thread safer libc (note: safer, not safe)

Access to the global _res structure replaced by pointers to a
per thread instance.  If unthreaded the pointer is to the
global structure.

Also replaced a 64k stack array with malloc-ed memory so
threaded aps (with a default 64k stack) have a chance at working.
ok deraadt@

1 files changed, 24 insertions, 18 deletions

diff --git a/src/lib/libc/net/res_query.c b/src/lib/libc/net/res_query.c
index 9c1aef1218..1e949e8efa 100644
--- a/src/lib/libc/net/res_query.c
+++ b/src/lib/libc/net/res_query.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: res_query.c,v 1.19 2002/06/27 09:55:49 itojun Exp $   */
+/*      $OpenBSD: res_query.c,v 1.20 2003/01/28 04:58:00 marc Exp $     */
 
 /*
  * ++Copyright++ 1988, 1993
@@ -60,7 +60,7 @@
 static char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
 static char rcsid[] = "$From: res_query.c,v 8.9 1996/09/22 00:13:28 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: res_query.c,v 1.19 2002/06/27 09:55:49 itojun Exp $";
+static char rcsid[] = "$OpenBSD: res_query.c,v 1.20 2003/01/28 04:58:00 marc Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -79,6 +79,8 @@ static char rcsid[] = "$OpenBSD: res_query.c,v 1.19 2002/06/27 09:55:49 itojun E
 #include <string.h>
 #include <unistd.h>
 
+#include "thread_private.h"
+
 #if PACKETSZ > 1024
 #define MAXPACKET       PACKETSZ
 #else
@@ -106,31 +108,32 @@ res_query(name, class, type, answer, anslen)
         u_char *answer;         /* buffer to put answer */
         int anslen;             /* size of answer buffer */
 {
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
         u_char buf[MAXPACKET];
         register HEADER *hp = (HEADER *) answer;
         int n;
 
         hp->rcode = NOERROR;    /* default */
 
-        if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+        if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
                 h_errno = NETDB_INTERNAL;
                 return (-1);
         }
 #ifdef DEBUG
-        if (_res.options & RES_DEBUG)
+        if (_resp->options & RES_DEBUG)
                 printf(";; res_query(%s, %d, %d)\n", name, class, type);
 #endif
 
         n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,
                         buf, sizeof(buf));
-        if (n > 0 && ((_res.options & RES_USE_EDNS0) ||
-            (_res.options & RES_USE_DNSSEC))) {
+        if (n > 0 && ((_resp->options & RES_USE_EDNS0) ||
+            (_resp->options & RES_USE_DNSSEC))) {
                 n = res_opt(n, buf, sizeof(buf), anslen);
         }
 
         if (n <= 0) {
 #ifdef DEBUG
-                if (_res.options & RES_DEBUG)
+                if (_resp->options & RES_DEBUG)
                         printf(";; res_query: mkquery failed\n");
 #endif
                 h_errno = NO_RECOVERY;
@@ -139,7 +142,7 @@ res_query(name, class, type, answer, anslen)
         n = res_send(buf, n, answer, anslen);
         if (n < 0) {
 #ifdef DEBUG
-                if (_res.options & RES_DEBUG)
+                if (_resp->options & RES_DEBUG)
                         printf(";; res_query: send error\n");
 #endif
                 h_errno = TRY_AGAIN;
@@ -148,7 +151,7 @@ res_query(name, class, type, answer, anslen)
 
         if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
 #ifdef DEBUG
-                if (_res.options & RES_DEBUG)
+                if (_resp->options & RES_DEBUG)
                         printf(";; rcode = %u, ancount=%u\n", hp->rcode,
                             ntohs(hp->ancount));
 #endif
@@ -188,12 +191,13 @@ res_search(name, class, type, answer, anslen)
         int anslen;             /* size of answer */
 {
         register const char *cp, * const *domain;
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
         HEADER *hp = (HEADER *) answer;
         u_int dots;
         int trailing_dot, ret, saved_herrno;
         int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
 
-        if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+        if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
                 h_errno = NETDB_INTERNAL;
                 return (-1);
         }
@@ -217,7 +221,7 @@ res_search(name, class, type, answer, anslen)
          * 'as is'.  The threshold can be set with the "ndots" option.
          */
         saved_herrno = -1;
-        if (dots >= _res.ndots) {
+        if (dots >= _resp->ndots) {
                 ret = res_querydomain(name, NULL, class, type, answer, anslen);
                 if (ret > 0)
                         return (ret);
@@ -231,11 +235,11 @@ res_search(name, class, type, answer, anslen)
          *      - there is at least one dot, there is no trailing dot,
          *        and RES_DNSRCH is set.
          */
-        if ((!dots && (_res.options & RES_DEFNAMES)) ||
-            (dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
+        if ((!dots && (_resp->options & RES_DEFNAMES)) ||
+            (dots && !trailing_dot && (_resp->options & RES_DNSRCH))) {
                 int done = 0;
 
-                for (domain = (const char * const *)_res.dnsrch;
+                for (domain = (const char * const *)_resp->dnsrch;
                      *domain && !done;
                      domain++) {
 
@@ -284,7 +288,7 @@ res_search(name, class, type, answer, anslen)
                         /* if we got here for some reason other than DNSRCH,
                          * we only wanted one iteration of the loop, so stop.
                          */
-                        if (!(_res.options & RES_DNSRCH))
+                        if (!(_resp->options & RES_DNSRCH))
                                 done++;
                 }
         }
@@ -326,16 +330,17 @@ res_querydomain(name, domain, class, type, answer, anslen)
         u_char *answer;         /* buffer to put answer */
         int anslen;             /* size of answer */
 {
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
         char nbuf[MAXDNAME*2+1+1];
         const char *longname = nbuf;
         int n;
 
-        if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+        if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
                 h_errno = NETDB_INTERNAL;
                 return (-1);
         }
 #ifdef DEBUG
-        if (_res.options & RES_DEBUG)
+        if (_resp->options & RES_DEBUG)
                 printf(";; res_querydomain(%s, %s, %d, %d)\n",
                        name, domain?domain:"<Nil>", class, type);
 #endif
@@ -361,6 +366,7 @@ const char *
 hostalias(name)
         register const char *name;
 {
+        struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
         register char *cp1, *cp2;
         FILE *fp;
         char *file;
@@ -368,7 +374,7 @@ hostalias(name)
         static char abuf[MAXDNAME];
         size_t len;
 
-        if (_res.options & RES_NOALIASES)
+        if (_resp->options & RES_NOALIASES)
                 return (NULL);
         file = getenv("HOSTALIASES");
         if (issetugid() != 0 || file == NULL || (fp = fopen(file, "r")) == NULL)