multipart-replace-http-server: be more flexible about getting sockets

1 files changed, 140 insertions, 30 deletions

diff --git a/multipart-replace-http-server.c b/multipart-replace-http-server.c
index c3e6219..a5b1c8b 100644
--- a/multipart-replace-http-server.c
+++ b/multipart-replace-http-server.c
@@ -1,14 +1,17 @@
 /* Copyright 2016 Luke Shumaker */
 
-#include <error.h>
+#include <ctype.h> /* for isdigit */
 #include <errno.h>
+#include <error.h>
+#include <fcntl.h> /* for open */
 #include <netdb.h> /* for {get,free}addrinfo() */
+#include <stdio.h>
 #include <stdlib.h> /* for EXIT_FAILURE */
+#include <string.h>
 #include <sys/socket.h>
-#include <stdio.h>
-#include <unistd.h>
 #include <sys/stat.h> /* for open */
-#include <fcntl.h> /* for open */
+#include <sys/un.h>
+#include <unistd.h>
 
 #include "util.h"
 #include "multipart-replace.h"
@@ -68,32 +71,123 @@ struct multipart_replace_stream *file_get(const char *filename) {
 	return NULL;
 }
 
-int tcp4_parse_listen(const char *port) {
-	int r;
-	struct addrinfo *addr = NULL;
-	struct addrinfo hints = { 0 };
-	hints.ai_family = AF_INET;
-	hints.ai_socktype = SOCK_STREAM;
-	hints.ai_flags = AI_PASSIVE;
+/* same error codes values as -getaddrinfo(); */
+int sockstream_listen(const char *type, const char *addr) {
+	int sock;
+	if (strcmp(type, "fd") == 0) {
+		if (strcmp(addr, "stdin") == 0) {
+			sock = 0;
+		} else if (strcmp(addr, "stdout") == 0) {
+			sock = 1;
+		} else if (strcmp(addr, "stderr") == 0) {
+			sock = 2;
+		} else if (strcmp(addr, "systemd") == 0) {
+			sock = 3; /* <systemd/sd-daemon.h>:SD_LISTEN_FDS_START */
+		} else {
+			for (size_t i = 0; addr[i] != '\0'; i++)
+				if (!isdigit(addr[i])) {
+					errno = EINVAL;
+					return -EAI_SYSTEM;
+				}
+			if (addr[0] == '\0') {
+				errno = EINVAL;
+				return -EAI_SYSTEM;
+			}
+			sock = atoi(addr);
+		}
+		/* 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 *col = strrchr(addr, ':');
+		if (col == NULL) {
+			errno = EINVAL;
+			return -EAI_SYSTEM;
+		}
+		char *host = strdupa(addr);
+		char *port = &col[1];
+		*col = '\0';
+		if (host[0] == '\0')
+			host = NULL;
 
-	if ((r = getaddrinfo(NULL, port, &hints, &addr)) != 0)
-		error(EXIT_FAILURE, r, _("Could not resolve TCP4 port %s"), port);
+		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 sock = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
-	if (sock < 0)
-		error(EXIT_FAILURE, errno, _("Could not create a TCP4 socket"));
+		int r = getaddrinfo(host, port, &ai_hints, &ai_addr);
+		if (r != 0)
+			return -r;
 
-	int yes = 1;
-	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
+		int sock = socket(ai_addr->ai_family, ai_addr->ai_socktype, ai_addr->ai_protocol);
+		if (sock < 0)
+			return -EAI_SYSTEM;
 
-	if (bind(sock, addr->ai_addr, addr->ai_addrlen) < 0)
-		error(EXIT_FAILURE, errno, _("Could not bind to TCP4 port %s"), port);
+		int yes = 1;
+		setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
 
-	if (listen(sock, 5) < 0)
-		error(EXIT_FAILURE, errno, _("Could not listen on TCP4 port %s"), port);
+		if (bind(sock, ai_addr->ai_addr, ai_addr->ai_addrlen) < 0)
+			return -EAI_SYSTEM;
 
-	freeaddrinfo(addr);
-	return sock;
+		if (listen(sock, SOMAXCONN) < 0)
+			return -EAI_SYSTEM;
+
+		freeaddrinfo(ai_addr);
+		return sock;
+	} else {
+		errno = EINVAL;
+		return -EAI_SYSTEM;
+	}
 }
 
 void connection_handler(int fd) {
@@ -153,20 +247,36 @@ void *connection_thread(void *arg_anon) {
 }
 
 void usage() {
-	printf("Usage: %s [-h] PORT [FILENAME...]\n", program_invocation_name);
+	printf("Usage: %s [-h] ADDRTYPE ADDR [FILENAME...]\n", program_invocation_name);
+	printf("Multiplex several multipart/x-mixed-replace streams over HTTP.\n"
+	       "\n"
+	       "ADDRTYPE is \"tcp4\", \"tcp6\", \"fd\", or \"unix\".  For tcp4/6, ADDR\n"
+	       "is a socket address in standard notation.  For fd, ADDR is \"stdin\",\n"
+	       "\"stdout\", \"stder\", \"systemd\", or an unsigned integer.  For unix,\n"
+	       "ADDR is a file path.\n"
+	       "\n"
+	       "The leading directories of the FILENAMEs are stripped; they are served\n"
+	       "at just the base filename.  As common sense should eventually suggest,\n"
+	       "the FILENAMEs should be pipes or sockets.\n");
 }
 
 int main(int argc, char *argv[]) {
-	if (argc < 2) {
+	if (strcmp(argv[1], "-h") == 0) {
+		usage();
+		return EXIT_SUCCESS;
+	}
+	if (argc < 3) {
 		dup2(2, 1);
 		usage();
 		return EXIT_FAILURE;
 	}
-	if (strcmp(argv[1], "-h") == 0) {
-		usage();
-		return EXIT_SUCCESS;
+	int sock = sockstream_listen(argv[1], argv[2]);
+	if (sock < 0) {
+		if (sock == -EAI_SYSTEM)
+			error(1, errno, "Opening socket %s %s", argv[1], argv[2]);
+		else
+			error(1, 0, "Opening socket %s %s: %s", argv[1], argv[2], gai_strerror(-sock));
 	}
-	int sock = tcp4_parse_listen(argv[1]);
 
 	for (int i = 2; i < argc; i++)
 		file_add(argv[i]);