don't mmap

Before we mmap(2) file for reading, and use a buffer to handle CGI
scripts.  Turns out, for sequential access over the whole mmap isn't
better than our loop on read.  This has also the additional advantage
that we can use handle_cgi (now handle_copy) for both files and CGI,
which is pretty cool.

This also fixes a nasty bug where we could hang a connection forever,
because we scheduled the wrong type of event (read on POLLOUT and
write on POLLIN, it's the other way around!)

gmid.h

@@ -171,9 +171,8 @@ struct client {
 	const char	*meta;
 	int		 fd, pfd;
 	DIR		*dir;
-	char		 sbuf[1024];	  /* static buffer */
-	void		*buf, *i;	  /* mmap buffer */
-	ssize_t		 len, off;	  /* mmap/static buffer  */
+	char		 sbuf[BUFSIZ];
+	ssize_t		 len, off;
 	struct sockaddr_storage	 addr;
 	struct vhost	*host;	/* host she's talking to */
 };

server.c

@@ -14,7 +14,6 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#include <sys/mman.h>
 #include <sys/stat.h>
 
 #include <netdb.h>
@@ -46,7 +45,6 @@ static inline void reschedule_write(int, struct client*, statefn);
 
 static int	 check_path(struct client*, const char*, int*);
 static void	 open_file(struct client*);
-static void	 load_file(struct client*);
 static void	 check_for_cgi(struct client*);
 static void	 handle_handshake(int, short, void*);
 static char	*strip_path(char*, int);
@@ -57,7 +55,6 @@ static void	 handle_open_conn(int, short, void*);
 static void	 start_reply(struct client*, int, const char*);
 static void	 handle_start_reply(int, short, void*);
 static void	 start_cgi(const char*, const char*, struct client*);
-static void	 send_file(int, short, void*);
 static void	 open_dir(struct client*);
 static void	 redirect_canonical_dir(struct client*);
 static void	 enter_handle_dirlist(int, short, void*);
@@ -65,7 +62,7 @@ static void	 handle_dirlist(int, short, void*);
 static int 	 read_next_dir_entry(struct client*);
 static void	 send_directory_listing(int, short, void*);
 static void	 handle_cgi_reply(int, short, void*);
-static void	 handle_cgi(int, short, void*);
+static void	 handle_copy(int, short, void*);
 static void	 close_conn(int, short, void*);
 static void	 do_accept(int, short, void*);
 static void	 handle_sighup(int, short, void*);
@@ -277,7 +274,8 @@ open_file(struct client *c)
 		/* fallthrough */
 
 	case FILE_EXISTS:
-		load_file(c);
+		c->next = handle_copy;
+		start_reply(c, SUCCESS, mime(c->host, c->iri.path));
 		return;
 
 	case FILE_DIRECTORY:
@@ -298,27 +296,6 @@ open_file(struct client *c)
 	}
 }
 
-static void
-load_file(struct client *c)
-{
-	if ((c->len = filesize(c->pfd)) == -1) {
-		log_err(c, "failed to get file size for %s: %s",
-		    c->iri.path, strerror(errno));
-		start_reply(c, TEMP_FAILURE, "internal server error");
-		return;
-	}
-
-	if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
-		    c->pfd, 0)) == MAP_FAILED) {
-		log_err(c, "mmap: %s: %s", c->iri.path, strerror(errno));
-		start_reply(c, TEMP_FAILURE, "internal server error");
-		return;
-	}
-	c->i = c->buf;
-	c->next = send_file;
-	start_reply(c, SUCCESS, mime(c->host, c->iri.path));
-}
-
 /*
  * the inverse of this algorithm, i.e. starting from the start of the
  * path + strlen(cgi), and checking if each component, should be
@@ -674,39 +651,6 @@ err:
 	fatal("cannot talk to the executor process");
 }
 
-static void
-send_file(int fd, short ev, void *d)
-{
-	struct client *c = d;
-	ssize_t ret, len;
-
-	len = (c->buf + c->len) - c->i;
-
-	while (len > 0) {
-		switch (ret = tls_write(c->ctx, c->i, len)) {
-		case -1:
-			log_err(c, "tls_write: %s", tls_error(c->ctx));
-			close_conn(fd, ev, c);
-			return;
-
-		case TLS_WANT_POLLIN:
-			reschedule_read(fd, c, &send_file);
-			return;
-
-		case TLS_WANT_POLLOUT:
-			reschedule_write(fd, c, &send_file);
-			return;
-
-		default:
-			c->i += ret;
-			len -= ret;
-			break;
-		}
-	}
-
-	close_conn(fd, ev, c);
-}
-
 static void
 open_dir(struct client *c)
 {
@@ -938,7 +882,7 @@ handle_cgi_reply(int fd, short ev, void *d)
 		log_request(c, c->sbuf, c->len);
 
 		c->off = 0;
-		handle_cgi(fd, ev, c);
+		handle_copy(fd, ev, c);
 		return;
 	}
 
@@ -946,39 +890,23 @@ handle_cgi_reply(int fd, short ev, void *d)
 }
 
 static void
-handle_cgi(int fd, short ev, void *d)
+handle_copy(int fd, short ev, void *d)
 {
 	struct client *c = d;
 	ssize_t r;
 
 	while (1) {
-		if (c->len == 0) {
-			switch (r = read(c->pfd, c->sbuf, sizeof(c->sbuf))) {
-			case 0:
-				goto end;
-			case -1:
-				if (errno == EAGAIN || errno == EWOULDBLOCK) {
-					reschedule_read(c->pfd, c, &handle_cgi);
-					return;
-				}
-				goto end;
-			default:
-				c->len = r;
-				c->off = 0;
-			}
-		}
-
 		while (c->len > 0) {
 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
 			case -1:
 				goto end;
 
 			case TLS_WANT_POLLOUT:
-				reschedule_read(c->fd, c, &handle_cgi);
+				reschedule_write(c->fd, c, &handle_copy);
 				return;
 
 			case TLS_WANT_POLLIN:
-				reschedule_write(c->fd, c, &handle_cgi);
+				reschedule_read(c->fd, c, &handle_copy);
 				return;
 
 			default:
@@ -987,6 +915,20 @@ handle_cgi(int fd, short ev, void *d)
 				break;
 			}
 		}
+
+		switch (r = read(c->pfd, c->sbuf, sizeof(c->sbuf))) {
+		case 0:
+			goto end;
+		case -1:
+			if (errno == EAGAIN || errno == EWOULDBLOCK) {
+				reschedule_read(c->pfd, c, &handle_copy);
+				return;
+			}
+			goto end;
+		default:
+			c->len = r;
+			c->off = 0;
+		}
 	}
 
 end:
@@ -1012,9 +954,6 @@ close_conn(int fd, short ev, void *d)
 	tls_free(c->ctx);
 	c->ctx = NULL;
 
-	if (c->buf != MAP_FAILED)
-		munmap(c->buf, c->len);
-
 	if (c->pfd != -1)
 		close(c->pfd);
 
@@ -1055,7 +994,6 @@ do_accept(int sock, short et, void *d)
 
 			c->fd = fd;
 			c->pfd = -1;
-			c->buf = MAP_FAILED;
 			c->dir = NULL;
 			c->addr = addr;