1 files changed, 130 insertions, 3 deletions

diff --git a/src/util.c b/src/util.c
index 46e6842..2ebeb4e 100644
--- a/src/util.c
+++ b/src/util.c
@@ -15,11 +15,15 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-
 #include <ctype.h> /* for isdigit */
-#include <stdlib.h>
-#include <error.h>
 #include <errno.h>
+#include <error.h>
+#include <netdb.h> /* for {get,free}addrinfo() */
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/stat.h> /* for open */
+#include <sys/un.h>
+#include <unistd.h> /* for unlink */
 
 #include "util.h"
 
@@ -86,3 +90,126 @@ int get_fd(const char *addr) {
 	}
 	return sock;
 }
+
+FILE *xfopen(const char *path, const char *mode) {
+	FILE *stream = fopen(path, mode);
+	if (stream == NULL)
+		error(EXIT_FAILURE, errno, "fopen: %s", path);
+	return stream;
+}
+
+FILE *xfdopen(const char *path, const char *mode) {
+	int fd = get_fd(path);
+	if (fd < 0)
+		error(EXIT_FAILURE, -fd, "get_fd: %s", path);
+	FILE *stream = fdopen(fd, mode);
+	if (stream == NULL)
+		error(EXIT_FAILURE, errno, "fdopen: %s (%d)", path, fd);
+	return stream;
+}
+
+/* same error codes values as -getaddrinfo(); */
+int sockstream_listen(const char *type, const char *addr) {
+	int sock;
+	if (strcmp(type, "fd") == 0) {
+		sock = get_fd(addr);
+		if (sock < 0) {
+			errno = -sock;
+			return -EAI_SYSTEM;
+		}
+		/* make sure it's a socket */
+		struct stat st;
+		if (fstat(sock, &st) < 0)
+			return -EAI_SYSTEM;
+		if (!S_ISSOCK(st.st_mode)) {
+			errno = ENOTSOCK;
+			return -EAI_SYSTEM;
+		}
+		/* make sure the socket is a stream */
+		int fd_socktype = 0;
+		socklen_t l = sizeof(fd_socktype);
+		if (getsockopt(sock, SOL_SOCKET, SO_TYPE, &fd_socktype, &l) < 0)
+			return -EAI_SYSTEM;
+		if (l != sizeof(fd_socktype)) {
+			errno = EINVAL;
+			return -EAI_SYSTEM;
+		}
+		if (fd_socktype != SOCK_STREAM) {
+			errno = ENOSTR;
+			return -EAI_SYSTEM;
+		}
+		/* make sure the socket is listening */
+		int fd_listening = 0;
+		l = sizeof(fd_listening);
+		if (getsockopt(sock, SOL_SOCKET, SO_ACCEPTCONN, &fd_listening, &l) < 0)
+			return -EAI_SYSTEM;
+		if (l != sizeof(fd_listening)) {
+			errno = EINVAL;
+			return -EAI_SYSTEM;
+		}
+		if (!fd_listening)
+			listen(sock, SOMAXCONN);
+		/* return the socket */
+		return sock;
+	} else if (strcmp(type, "unix") == 0) {
+		struct sockaddr_un un_addr = { 0 };
+		if (strlen(addr)+1 > sizeof(un_addr.sun_path)) {
+			errno = ENAMETOOLONG;
+			return -EAI_SYSTEM;
+		}
+		un_addr.sun_family = AF_UNIX;
+		strcpy(un_addr.sun_path, addr);
+		int sock = socket(AF_UNIX, SOCK_STREAM, 0);
+		if (sock < 0)
+			return -EAI_SYSTEM;
+		unlink(addr);
+		if (bind(sock, (struct sockaddr *)&un_addr, sizeof(un_addr)) < 0)
+			return -EAI_SYSTEM;
+		if (listen(sock, SOMAXCONN) < 0)
+			return -EAI_SYSTEM;
+		return sock;
+	} else if (strcmp(type, "tcp4") == 0 || strcmp(type, "tcp6") == 0) {
+		struct addrinfo *ai_addr = NULL;
+		struct addrinfo ai_hints = { 0 };
+
+		char *host = strdupa(addr);
+		char *col = strrchr(host, ':');
+		if (col == NULL) {
+			errno = EINVAL;
+			return -EAI_SYSTEM;
+		}
+		char *port = &col[1];
+		*col = '\0';
+		if (host[0] == '\0')
+			host = NULL;
+
+		ai_hints.ai_family = (strcmp(type, "tcp6") == 0) ? AF_INET6 : AF_INET;
+		ai_hints.ai_socktype = SOCK_STREAM;
+		ai_hints.ai_flags = AI_PASSIVE;
+
+		int r = getaddrinfo(host, port, &ai_hints, &ai_addr);
+		if (r < 0)
+			return r;
+		if (r > 0)
+			return -r;
+
+		int sock = socket(ai_addr->ai_family, ai_addr->ai_socktype, ai_addr->ai_protocol);
+		if (sock < 0)
+			return -EAI_SYSTEM;
+
+		int yes = 1;
+		setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
+
+		if (bind(sock, ai_addr->ai_addr, ai_addr->ai_addrlen) < 0)
+			return -EAI_SYSTEM;
+
+		if (listen(sock, SOMAXCONN) < 0)
+			return -EAI_SYSTEM;
+
+		freeaddrinfo(ai_addr);
+		return sock;
+	} else {
+		errno = EINVAL;
+		return -EAI_SYSTEM;
+	}
+}