libmpdclient: added resolver library

The resolver library provides unified access to all resolvers
(getaddrinfo(), gethostbyname(), Unix domain sockets).  Like
getaddrinfo(), it can return more than one address for a host name.
This fixes bug 1517 (http://www.musicpd.org/mantis/view.php?id=1517).

4 files changed, 327 insertions, 199 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 31cabfda0..b652ede98 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -12,6 +12,7 @@ ncmpc_LDADD = \
 
 ncmpc_headers = \
   libmpdclient.h\
+	resolver.h \
 	song.h \
   mpdclient.h\
 	playlist.h \
@@ -40,6 +41,7 @@ lyr_src=${lyr_src_fixed}
 
 ncmpc_SOURCES = \
   libmpdclient.c\
+	resolver.c \
 	song.c \
   main.c\
   mpdclient.c\
diff --git a/src/libmpdclient.c b/src/libmpdclient.c
index b2c907b49..0f2b1b503 100644
--- a/src/libmpdclient.c
+++ b/src/libmpdclient.c
@@ -31,6 +31,7 @@
 */
 
 #include "libmpdclient.h"
+#include "resolver.h"
 #include "str_pool.h"
 
 #include <assert.h>
@@ -61,12 +62,6 @@
 #  define MSG_DONTWAIT 0
 #endif
 
-#ifndef MPD_NO_GAI
-#  ifdef AI_ADDRCONFIG
-#    define MPD_HAVE_GAI
-#  endif
-#endif
-
 #define COMMAND_LIST    1
 #define COMMAND_LIST_OK 2
 
@@ -115,130 +110,6 @@ static int do_connect_fail(mpd_Connection *connection,
 }
 #endif /* !WIN32 */
 
-#ifdef MPD_HAVE_GAI
-static int mpd_connect(mpd_Connection * connection, const char * host, int port,
-                       float timeout)
-{
-	int error;
-	char service[20];
-	struct addrinfo hints;
-	struct addrinfo *res = NULL;
-	struct addrinfo *addrinfo = NULL;
-
-	/**
-	 * Setup hints
-	 */
-	hints.ai_flags     = AI_ADDRCONFIG;
-	hints.ai_family    = PF_UNSPEC;
-	hints.ai_socktype  = SOCK_STREAM;
-	hints.ai_protocol  = IPPROTO_TCP;
-	hints.ai_addrlen   = 0;
-	hints.ai_addr      = NULL;
-	hints.ai_canonname = NULL;
-	hints.ai_next      = NULL;
-
-	snprintf(service, sizeof(service), "%d", port);
-
-	error = getaddrinfo(host, service, &hints, &addrinfo);
-
-	if (error) {
-		snprintf(connection->errorStr, sizeof(connection->errorStr),
-			 "host \"%s\" not found: %s",host, gai_strerror(error));
-		connection->error = MPD_ERROR_UNKHOST;
-		return -1;
-	}
-
-	for (res = addrinfo; res; res = res->ai_next) {
-		/* create socket */
-		connection->sock = socket(res->ai_family, SOCK_STREAM, res->ai_protocol);
-		if (connection->sock < 0) {
-			snprintf(connection->errorStr, sizeof(connection->errorStr),
-			         "problems creating socket: %s",
-			         strerror(errno));
-			connection->error = MPD_ERROR_SYSTEM;
-			freeaddrinfo(addrinfo);
-			return -1;
-		}
-
-		mpd_setConnectionTimeout(connection,timeout);
-
-		/* connect stuff */
- 		if (do_connect_fail(connection, res->ai_addr, res->ai_addrlen)) {
- 			/* try the next address family */
- 			closesocket(connection->sock);
- 			connection->sock = -1;
- 			continue;
-		}
-	}
-	freeaddrinfo(addrinfo);
-
-	if (connection->sock < 0) {
-		snprintf(connection->errorStr, sizeof(connection->errorStr),
-			 "problems connecting to \"%s\" on port"
-			 " %i: %s",host,port, strerror(errno));
-		connection->error = MPD_ERROR_CONNPORT;
-
-		return -1;
-	}
-
-	return 0;
-}
-#else /* !MPD_HAVE_GAI */
-static int mpd_connect(mpd_Connection * connection, const char * host, int port,
-                       float timeout)
-{
-	struct hostent * he;
-	struct sockaddr * dest;
-	int destlen;
-	struct sockaddr_in sin;
-
-	if(!(he=gethostbyname(host))) {
-		snprintf(connection->errorStr, sizeof(connection->errorStr),
-			 "host \"%s\" not found",host);
-		connection->error = MPD_ERROR_UNKHOST;
-		return -1;
-	}
-
-	memset(&sin,0,sizeof(struct sockaddr_in));
-	/*dest.sin_family = he->h_addrtype;*/
-	sin.sin_family = AF_INET;
-	sin.sin_port = htons(port);
-
-	switch(he->h_addrtype) {
-	case AF_INET:
-		memcpy((char *)&sin.sin_addr.s_addr,(char *)he->h_addr,
-				he->h_length);
-		dest = (struct sockaddr *)&sin;
-		destlen = sizeof(struct sockaddr_in);
-		break;
-	default:
-		strcpy(connection->errorStr,"address type is not IPv4\n");
-		connection->error = MPD_ERROR_SYSTEM;
-		return -1;
-		break;
-	}
-
-	if((connection->sock = socket(dest->sa_family,SOCK_STREAM,0))<0) {
-		strcpy(connection->errorStr,"problems creating socket");
-		connection->error = MPD_ERROR_SYSTEM;
-		return -1;
-	}
-
-	mpd_setConnectionTimeout(connection,timeout);
-
-	/* connect stuff */
-	if (do_connect_fail(connection, dest, destlen)) {
-		snprintf(connection->errorStr, sizeof(connection->errorStr),
-			 "problems connecting to \"%s\" on port"
-			 " %i",host,port);
-		connection->error = MPD_ERROR_CONNPORT;
-		return -1;
-	}
-
-	return 0;
-}
-#endif /* !MPD_HAVE_GAI */
-
 const char *const mpdTagItemKeys[MPD_TAG_NUM_OF_ITEM_TYPES] =
 {
 	"Artist",
@@ -333,53 +204,6 @@ static int mpd_parseWelcome(mpd_Connection * connection, const char * host, int
 	return 0;
 }
 
-#ifndef WIN32
-static int mpd_connect_un(mpd_Connection * connection,
-			  const char * host, float timeout)
-{
-	int error, flags;
-	size_t path_length;
-	struct sockaddr_un sun;
-
-	path_length = strlen(host);
-	if (path_length >= sizeof(sun.sun_path)) {
-		strcpy(connection->errorStr, "unix socket path is too long");
-		connection->error = MPD_ERROR_UNKHOST;
-		return -1;
-	}
-
-	sun.sun_family = AF_UNIX;
-	memcpy(sun.sun_path, host, path_length + 1);
-
-	connection->sock = socket(AF_UNIX, SOCK_STREAM, 0);
-	if (connection->sock < 0) {
-		strcpy(connection->errorStr, "problems creating socket");
-		connection->error = MPD_ERROR_SYSTEM;
-		return -1;
-	}
-
-	mpd_setConnectionTimeout(connection, timeout);
-
-	flags = fcntl(connection->sock, F_GETFL, 0);
-	fcntl(connection->sock, F_SETFL, flags | O_NONBLOCK);
-
-	error = connect(connection->sock, (struct sockaddr*)&sun, sizeof(sun));
-	if (error < 0) {
-		/* try the next address family */
-		close(connection->sock);
-		connection->sock = 0;
-
-		snprintf(connection->errorStr, sizeof(connection->errorStr),
-			 "problems connecting to \"%s\": %s",
-			 host, strerror(errno));
-		connection->error = MPD_ERROR_CONNPORT;
-		return -1;
-	}
-
-	return 0;
-}
-#endif /* WIN32 */
-
 /**
  * Wait for the socket to become readable.
  */
@@ -486,6 +310,76 @@ static int mpd_recv(mpd_Connection *connection)
 	}
 }
 
+static int
+mpd_connect(mpd_Connection *connection, const char * host, int port)
+{
+	struct resolver *resolver;
+	const struct resolver_address *address;
+	int ret;
+
+	resolver = resolver_new(host, port);
+	if (resolver == NULL) {
+		snprintf(connection->errorStr, sizeof(connection->errorStr),
+			 "host \"%s\" not found", host);
+		connection->error = MPD_ERROR_UNKHOST;
+		return -1;
+	}
+
+	while ((address = resolver_next(resolver)) != NULL) {
+		connection->sock = socket(address->family, SOCK_STREAM,
+					  address->protocol);
+		if (connection->sock < 0) {
+			snprintf(connection->errorStr,
+				 sizeof(connection->errorStr),
+				 "problems creating socket: %s",
+				 strerror(errno));
+			connection->error = MPD_ERROR_SYSTEM;
+			continue;
+		}
+
+		ret = do_connect_fail(connection,
+				      address->addr, address->addrlen);
+		if (ret != 0) {
+			snprintf(connection->errorStr,
+				 sizeof(connection->errorStr),
+				 "problems connecting to \"%s\" on port"
+				 " %i: %s", host, port, strerror(errno));
+			connection->error = MPD_ERROR_CONNPORT;
+
+			closesocket(connection->sock);
+			connection->sock = -1;
+			continue;
+		}
+
+		ret = mpd_wait_connected(connection);
+		if (ret > 0) {
+			resolver_free(resolver);
+			mpd_clearError(connection);
+			return 0;
+		}
+
+		if (ret == 0) {
+			snprintf(connection->errorStr,
+				 sizeof(connection->errorStr),
+				 "timeout in attempting to get a response from"
+				 " \"%s\" on port %i", host, port);
+			connection->error = MPD_ERROR_NORESPONSE;
+		} else if (ret < 0) {
+			snprintf(connection->errorStr,
+				 sizeof(connection->errorStr),
+				 "problems connecting to \"%s\" on port %i: %s",
+				 host, port, strerror(-ret));
+			connection->error = MPD_ERROR_CONNPORT;
+		}
+
+		closesocket(connection->sock);
+		connection->sock = -1;
+	}
+
+	resolver_free(resolver);
+	return -1;
+}
+
 mpd_Connection * mpd_newConnection(const char * host, int port, float timeout) {
 	int err;
 	char * rt;
@@ -504,30 +398,11 @@ mpd_Connection * mpd_newConnection(const char * host, int port, float timeout) {
 	if (winsock_dll_error(connection))
 		return connection;
 
-#ifndef WIN32
-	if (host[0] == '/')
-		err = mpd_connect_un(connection, host, timeout);
-	else
-#endif
-		err = mpd_connect(connection, host, port, timeout);
-	if (err < 0)
-		return connection;
+	mpd_setConnectionTimeout(connection,timeout);
 
-	err = mpd_wait_connected(connection);
-	if (err == 0) {
-		snprintf(connection->errorStr, sizeof(connection->errorStr),
-			 "timeout in attempting to get a response from"
-			 " \"%s\" on port %i",host,port);
-		connection->error = MPD_ERROR_NORESPONSE;
-		return connection;
-	} else if (err < 0) {
-		snprintf(connection->errorStr,
-			 sizeof(connection->errorStr),
-			 "problems connecting to \"%s\" on port %i: %s",
-			 host, port, strerror(-err));
-		connection->error = MPD_ERROR_CONNPORT;
+	err = mpd_connect(connection, host, port);
+	if (err < 0)
 		return connection;
-	}
 
 	while(!(rt = memchr(connection->buffer, '\n', connection->buflen))) {
 		err = mpd_recv(connection);
diff --git a/src/resolver.c b/src/resolver.c
new file mode 100644
index 000000000..e5df05ce5
--- /dev/null
+++ b/src/resolver.c
@@ -0,0 +1,195 @@
+/* libmpdclient
+   (c) 2008 Max Kellermann <max@duempel.org>
+   This project's homepage is: http://www.musicpd.org
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+   - Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+   - Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+   - Neither the name of the Music Player Daemon nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include "resolver.h"
+
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef WIN32
+#  include <ws2tcpip.h>
+#  include <winsock.h>
+#else
+#  include <netinet/in.h>
+#  include <arpa/inet.h>
+#  include <sys/socket.h>
+#  include <sys/un.h>
+#  include <netdb.h>
+#endif
+
+#ifndef MPD_NO_GAI
+#  ifdef AI_ADDRCONFIG
+#    define MPD_HAVE_GAI
+#  endif
+#endif
+
+struct resolver {
+	enum {
+		TYPE_ZERO, TYPE_ONE, TYPE_ANY
+	} type;
+
+#ifdef MPD_HAVE_GAI
+	struct addrinfo *ai;
+	const struct addrinfo *next;
+#else
+	struct sockaddr_in sin;
+#endif
+
+	struct resolver_address current;
+
+#ifndef WIN32
+	struct sockaddr_un sun;
+#endif
+};
+
+struct resolver *
+resolver_new(const char *host, int port)
+{
+	struct resolver *resolver;
+
+	resolver = malloc(sizeof(*resolver));
+	if (resolver == NULL)
+		return NULL;
+
+#ifndef WIN32
+	if (host[0] == '/') {
+		size_t path_length = strlen(host);
+		if (path_length >= sizeof(resolver->sun.sun_path)) {
+			free(resolver);
+			return NULL;
+		}
+
+		resolver->sun.sun_family = AF_UNIX;
+		memcpy(resolver->sun.sun_path, host, path_length + 1);
+
+		resolver->current.family = PF_UNIX;
+		resolver->current.protocol = 0;
+		resolver->current.addrlen = sizeof(resolver->sun);
+		resolver->current.addr = (const struct sockaddr *)&resolver->sun;
+		resolver->type = TYPE_ONE;
+	} else {
+#endif
+#ifdef MPD_HAVE_GAI
+		struct addrinfo hints;
+		char service[20];
+		int ret;
+
+		memset(&hints, 0, sizeof(hints));
+		hints.ai_flags = AI_ADDRCONFIG;
+		hints.ai_family = PF_UNSPEC;
+		hints.ai_socktype = SOCK_STREAM;
+		hints.ai_protocol = IPPROTO_TCP;
+
+		snprintf(service, sizeof(service), "%d", port);
+
+		ret = getaddrinfo(host, service, &hints, &resolver->ai);
+		if (ret != 0) {
+			free(resolver);
+			return NULL;
+		}
+
+		resolver->next = resolver->ai;
+		resolver->type = TYPE_ANY;
+#else
+		const struct hostent *he;
+
+		he = gethostbyname(host);
+		if (he == NULL) {
+			free(resolver);
+			return NULL;
+		}
+
+		if (he->h_addrtype != AF_INET) {
+			free(resolver);
+			return NULL;
+		}
+
+
+		memset(&resolver->sin, 0, sizeof(resolver->sin));
+		resolver->sin.sin_family = AF_INET;
+		resolver->sin.sin_port = htons(port);
+		memcpy((char *)&resolver->sin.sin_addr.s_addr,
+		       (char *)he->h_addr, he->h_length);
+
+		resolver->current.family = PF_INET;
+		resolver->current.protocol = 0;
+		resolver->current.addrlen = sizeof(resolver->sin);
+		resolver->current.addr = (const struct sockaddr *)&resolver->sin;
+
+		resolver->type = TYPE_ONE;
+#endif
+#ifndef WIN32
+	}
+#endif
+
+	return resolver;
+}
+
+void
+resolver_free(struct resolver *resolver)
+{
+#ifdef MPD_HAVE_GAI
+	if (resolver->type == TYPE_ANY)
+		freeaddrinfo(resolver->ai);
+#endif
+	free(resolver);
+}
+
+const struct resolver_address *
+resolver_next(struct resolver *resolver)
+{
+	if (resolver->type == TYPE_ZERO)
+		return NULL;
+
+	if (resolver->type == TYPE_ONE) {
+		resolver->type = TYPE_ZERO;
+		return &resolver->current;
+	}
+
+#ifdef MPD_HAVE_GAI
+	if (resolver->next == NULL)
+		return NULL;
+
+	resolver->current.family = resolver->next->ai_family;
+	resolver->current.protocol = resolver->next->ai_protocol;
+	resolver->current.addrlen = resolver->next->ai_addrlen;
+	resolver->current.addr = resolver->next->ai_addr;
+
+	resolver->next = resolver->next->ai_next;
+
+	return &resolver->current;
+#else
+	return NULL;
+#endif
+}
diff --git a/src/resolver.h b/src/resolver.h
new file mode 100644
index 000000000..6a79dc4cb
--- /dev/null
+++ b/src/resolver.h
@@ -0,0 +1,56 @@
+/* libmpdclient
+   (c) 2008 Max Kellermann <max@duempel.org>
+   This project's homepage is: http://www.musicpd.org
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+   - Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+   - Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+   - Neither the name of the Music Player Daemon nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef LIBMPDCLIENT_RESOLVER_H
+#define LIBMPDCLIENT_RESOLVER_H
+
+#include <stddef.h>
+
+struct resolver;
+
+struct resolver_address {
+	int family;
+	int protocol;
+	size_t addrlen;
+	const struct sockaddr *addr;
+};
+
+struct resolver *
+resolver_new(const char *host, int port);
+
+void
+resolver_free(struct resolver *resolver);
+
+const struct resolver_address *
+resolver_next(struct resolver *resolver);
+
+#endif