main/libc0.9.32: fix resolver to return TRY_AGAIN on timeout

This improves error handling for certain programs. E.g. postfix.

2 files changed, 268 insertions, 1 deletions

diff --git a/main/libc0.9.32/0001-resolv-fix-resolver-to-return-TRY_AGAIN-on-timeout.patch b/main/libc0.9.32/0001-resolv-fix-resolver-to-return-TRY_AGAIN-on-timeout.patch
new file mode 100644
index 0000000000..8d6af3deb5
--- /dev/null
+++ b/main/libc0.9.32/0001-resolv-fix-resolver-to-return-TRY_AGAIN-on-timeout.patch
@@ -0,0 +1,265 @@
+From f32b4d27b352724f28c7409490338929fc7ba58f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Timo=20Ter=C3=A4s?= <timo.teras@iki.fi>
+Date: Thu, 7 Jul 2011 18:47:26 +0300
+Subject: [PATCH] resolv: fix resolver to return TRY_AGAIN on timeout
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This fixes the internal __dns_lookup to get a h_errno pointer so
+it works nicely with the _r variants. Additionally the function is
+modified to permanent error if the static buffer lengths are not
+enough. And finally it fixed to return TRY_AGAIN if the nameservers
+timeout.
+
+res_search is fixed to continue searching if we receive TRY_AGAIN.
+It could be a problem with the specific search domain's server
+and not necessarily a problem in the recursive resolver we are
+querying. For same reason, it does not make sense to differentiate
+timeout or SERVFAIL error reply.
+
+The biggest issue this fixes is that we now properly set h_errno
+to TRY_AGAIN if upstream nameserver(s) timed out. Previously we
+would have returned NETDB_INTERNAL.
+
+Signed-off-by: Timo Teräs <timo.teras@iki.fi>
+---
+ libc/inet/resolv.c |   95 +++++++++++++++++++++++++++-------------------------
+ 1 files changed, 49 insertions(+), 46 deletions(-)
+
+diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
+index dc8a752..90ba31c 100644
+--- a/libc/inet/resolv.c
++++ b/libc/inet/resolv.c
+@@ -456,7 +456,8 @@ extern int __read_etc_hosts_r(parser_t *parser,
+ extern int __dns_lookup(const char *name,
+ 		int type,
+ 		unsigned char **outpacket,
+-		struct resolv_answer *a) attribute_hidden;
++		struct resolv_answer *a,
++		int *h_errnop) attribute_hidden;
+ extern int __encode_dotted(const char *dotted,
+ 		unsigned char *dest,
+ 		int maxlen) attribute_hidden;
+@@ -1233,7 +1234,8 @@ static int __decode_answer(const unsigned char *message, /* packet */
+ int attribute_hidden __dns_lookup(const char *name,
+ 		int type,
+ 		unsigned char **outpacket,
+-		struct resolv_answer *a)
++		struct resolv_answer *a,
++		int *h_errnop)
+ {
+ 	/* Protected by __resolv_lock: */
+ 	static int last_ns_num = 0;
+@@ -1265,11 +1267,15 @@ int attribute_hidden __dns_lookup(const char *name,
+ 	fd = -1;
+ 	lookup = NULL;
+ 	name_len = strlen(name);
+-	if ((unsigned)name_len >= MAXDNAME - MAXLEN_searchdomain - 2)
+-		goto fail; /* paranoia */
++	if ((unsigned)name_len >= MAXDNAME - MAXLEN_searchdomain - 2) {
++		*h_errnop = NO_RECOVERY;
++		goto fail1; /* paranoia */
++	}
+ 	lookup = malloc(name_len + 1/*for '.'*/ + MAXLEN_searchdomain + 1);
+-	if (!packet || !lookup || !name[0])
+-		goto fail;
++	if (!packet || !lookup || !name[0]) {
++		*h_errnop = NO_RECOVERY;
++		goto fail1;
++	}
+ 	ends_with_dot = (name[name_len - 1] == '.');
+ 	/* no strcpy! paranoia, user might change name[] under us */
+ 	memcpy(lookup, name, name_len);
+@@ -1337,8 +1343,10 @@ int attribute_hidden __dns_lookup(const char *name,
+ 		h.rd = 1;
+ 		DPRINTF("encoding header\n", h.rd);
+ 		i = __encode_header(&h, packet, PACKETSZ);
+-		if (i < 0)
+-			goto fail;
++		if (i < 0) {
++			*h_errnop = NO_RECOVERY;
++			goto fail1;
++		}
+ 
+ 		/* encode question */
+ 		DPRINTF("lookup name: %s\n", lookup);
+@@ -1346,8 +1354,10 @@ int attribute_hidden __dns_lookup(const char *name,
+ 		q.qtype = type;
+ 		q.qclass = C_IN; /* CLASS_IN */
+ 		j = __encode_question(&q, packet+i, PACKETSZ-i);
+-		if (j < 0)
+-			goto fail;
++		if (j < 0) {
++			*h_errnop = NO_RECOVERY;
++			goto fail1;
++		}
+ 		packet_len = i + j;
+ 
+ 		/* send packet */
+@@ -1473,7 +1483,7 @@ int attribute_hidden __dns_lookup(const char *name,
+ 				/* no more search domains to try */
+ 			}
+ 			/* dont loop, this is "no such host" situation */
+-			h_errno = HOST_NOT_FOUND;
++			*h_errnop = HOST_NOT_FOUND;
+ 			goto fail1;
+ 		}
+ 		/* Insert other non-fatal errors here, which do not warrant
+@@ -1485,7 +1495,7 @@ int attribute_hidden __dns_lookup(const char *name,
+ 
+ 		/* Code below won't work correctly with h.ancount == 0, so... */
+ 		if (h.ancount <= 0) {
+-			h_errno = NO_DATA; /* [is this correct code to check for?] */
++			*h_errnop = NO_DATA; /* [is this correct code to check for?] */
+ 			goto fail1;
+ 		}
+ 		pos = HFIXEDSZ;
+@@ -1562,8 +1572,7 @@ int attribute_hidden __dns_lookup(const char *name,
+ 		variant = -1;
+ 	} while (retries_left > 0);
+ 
+- fail:
+-	h_errno = NETDB_INTERNAL;
++	*h_errnop = TRY_AGAIN;
+  fail1:
+ 	if (fd != -1)
+ 		close(fd);
+@@ -2104,9 +2113,8 @@ int gethostbyname_r(const char *name,
+ 	 * we'll need space of one in_addr + two addr_list[] elems */
+ 	a.buflen = buflen - ((sizeof(addr_list[0]) * 2 + sizeof(struct in_addr)));
+ 	a.add_count = 0;
+-	packet_len = __dns_lookup(name, T_A, &packet, &a);
++	packet_len = __dns_lookup(name, T_A, &packet, &a, h_errnop);
+ 	if (packet_len < 0) {
+-		*h_errnop = HOST_NOT_FOUND;
+ 		DPRINTF("__dns_lookup returned < 0\n");
+ 		return TRY_AGAIN;
+ 	}
+@@ -2290,9 +2298,8 @@ int gethostbyname2_r(const char *name,
+ 		int packet_len;
+ 
+ /* Hmm why we memset(a) to zeros only once? */
+-		packet_len = __dns_lookup(buf, T_AAAA, &packet, &a);
++		packet_len = __dns_lookup(buf, T_AAAA, &packet, &a, h_errnop);
+ 		if (packet_len < 0) {
+-			*h_errnop = HOST_NOT_FOUND;
+ 			return TRY_AGAIN;
+ 		}
+ 		strncpy(buf, a.dotted, buflen);
+@@ -2448,9 +2455,8 @@ int gethostbyaddr_r(const void *addr, socklen_t addrlen,
+ 	memset(&a, '\0', sizeof(a));
+ 	for (;;) {
+ /* Hmm why we memset(a) to zeros only once? */
+-		packet_len = __dns_lookup(buf, T_PTR, &packet, &a);
++		packet_len = __dns_lookup(buf, T_PTR, &packet, &a, h_errnop);
+ 		if (packet_len < 0) {
+-			*h_errnop = HOST_NOT_FOUND;
+ 			return TRY_AGAIN;
+ 		}
+ 
+@@ -3089,7 +3095,7 @@ int res_query(const char *dname, int class, int type,
+ 	}
+ 
+ 	memset(&a, '\0', sizeof(a));
+-	i = __dns_lookup(dname, type, &packet, &a);
++	i = __dns_lookup(dname, type, &packet, &a, &h_errno);
+ 
+ 	if (i < 0) {
+ 		if (!h_errno) /* TODO: can this ever happen? */
+@@ -3117,14 +3123,13 @@ libc_hidden_def(res_query)
+  */
+ #define __TRAILING_DOT	(1<<0)
+ #define __GOT_NODATA	(1<<1)
+-#define __GOT_SERVFAIL	(1<<2)
++#define __GOT_TRYAGAIN	(1<<2)
+ #define __TRIED_AS_IS	(1<<3)
+ int res_search(const char *name, int class, int type, u_char *answer,
+ 		int anslen)
+ {
+ 	const char *cp;
+ 	char **domain;
+-	HEADER *hp = (HEADER *)(void *)answer;
+ 	unsigned dots;
+ 	unsigned state;
+ 	int ret, saved_herrno;
+@@ -3189,19 +3194,9 @@ int res_search(const char *name, int class, int type, u_char *answer,
+ 			if (ret > 0)
+ 				return ret;
+ 
+-			/*
+-			 * If no server present, give up.
+-			 * If name isn't found in this domain,
+-			 * keep trying higher domains in the search list
+-			 * (if that's enabled).
+-			 * On a NO_DATA error, keep trying, otherwise
+-			 * a wildcard entry of another type could keep us
+-			 * from finding this entry higher in the domain.
+-			 * If we get some other error (negative answer or
+-			 * server failure), then stop searching up,
+-			 * but try the input name below in case it's
+-			 * fully-qualified.
+-			 */
++			/* our resolver refused to talk to us -
++			 * no sense to retry, as the retry would likely
++			 * fail too */
+ 			if (errno == ECONNREFUSED) {
+ 				h_errno = TRY_AGAIN;
+ 				return -1;
+@@ -3209,21 +3204,29 @@ int res_search(const char *name, int class, int type, u_char *answer,
+ 
+ 			switch (h_errno) {
+ 				case NO_DATA:
++					/* Keep trying, otherwise a
++					 * wildcard entry of another type
++					 * could keep us from finding this
++					 * entry from higher in the domain
++					 * search. */
+ 					state |= __GOT_NODATA;
+-					/* FALLTHROUGH */
++					break;
+ 				case HOST_NOT_FOUND:
+-					/* keep trying */
++					/* Not found - keep trying higher
++					 * domains in the search list. */
+ 					break;
+ 				case TRY_AGAIN:
+-					if (hp->rcode == SERVFAIL) {
+-						/* try next search element, if any */
+-						state |= __GOT_SERVFAIL;
+-						break;
+-					}
+-					/* FALLTHROUGH */
++					/* Server error or timeout. Could
++					 * be caused by a problem in servers
++					 * our resolver queried. Keep trying
++					 * search, but remember that there
++					 * was a temporary problem. */
++					state |= __GOT_TRYAGAIN;
++					break;
+ 				default:
+ 					/* anything else implies that we're done */
+ 					done = 1;
++					break;
+ 			}
+ 			/*
+ 			 * if we got here for some reason other than DNSRCH,
+@@ -3257,13 +3260,13 @@ int res_search(const char *name, int class, int type, u_char *answer,
+ 		h_errno = saved_herrno;
+ 	else if (state & __GOT_NODATA)
+ 		h_errno = NO_DATA;
+-	else if (state & __GOT_SERVFAIL)
++	else if (state & __GOT_TRYAGAIN)
+ 		h_errno = TRY_AGAIN;
+ 	return -1;
+ }
+ #undef __TRAILING_DOT
+ #undef __GOT_NODATA
+-#undef __GOT_SERVFAIL
++#undef __GOT_TRYAGAIN
+ #undef __TRIED_AS_IS
+ /*
+  * Perform a call on res_query on the concatenation of name and domain,
+-- 
+1.7.1
+
diff --git a/main/libc0.9.32/APKBUILD b/main/libc0.9.32/APKBUILD
index e55ff220cc..d812dddbe0 100644
--- a/main/libc0.9.32/APKBUILD
+++ b/main/libc0.9.32/APKBUILD
@@ -4,7 +4,7 @@ pkgname=libc$_abiver
 _gitver=
 pkgver=0.9.32
 _ver=${pkgver/_/-}
-pkgrel=0
+pkgrel=1
 pkgdesc="C library for developing embedded Linux systems"
 url=http://uclibc.org
 license="LGPL-2"
@@ -22,6 +22,7 @@ _snapfile="$pkgname-$pkgver.tar.bz2"
 source="http://uclibc.org/downloads/uClibc-${_ver}.tar.bz2
 	compat-stack-guard.patch
 	uclibc-resolv-cname-fix.diff
+	0001-resolv-fix-resolver-to-return-TRY_AGAIN-on-timeout.patch
 	0001-libm-x86_64-implement-fesetround.patch
 	0001-ldso-limited-support-for-ORIGIN-in-rpath.patch
 	0002-stdlib-fix-arc4random-return-type-to-u_int32_t.patch
@@ -129,6 +130,7 @@ libthread_db() {
 md5sums="cfcb6c25d8ebe12817499d8749ee8ae1  uClibc-0.9.32.tar.bz2
 a9bfb77ea7dc5fb9abf4d4b19201c614  compat-stack-guard.patch
 5d6e3e382b66f59cfd7242a4fe453f98  uclibc-resolv-cname-fix.diff
+08f31006426a0fca561f262f36bcfb01  0001-resolv-fix-resolver-to-return-TRY_AGAIN-on-timeout.patch
 e0c901502602f7e9e002d910d0f32ab9  0001-libm-x86_64-implement-fesetround.patch
 bc164e262c5feab55c800780704fa71c  0001-ldso-limited-support-for-ORIGIN-in-rpath.patch
 b4fb68ad3d0e8331b1b40c30eb21dfdc  0002-stdlib-fix-arc4random-return-type-to-u_int32_t.patch