Reduce global state by localizing the server-struct

The server-struct variable s was global, which made it readable and
modifiable from any point in the code. Making it a local variable in
main() instead and passing it as a pointer to constant memory to each
function needing it makes much more sense and allows the compiler to
warn us if we do try to modify it, which it wouldn't have before.

Signed-off-by: Laslo Hunhold <dev@frign.de>

http.c

@@ -528,7 +528,7 @@ parse_range(const char *str, size_t size, size_t *lower, size_t *upper)
 #define RELPATH(x) ((!*(x) || !strcmp(x, "/")) ? "." : ((x) + 1))
 
 enum status
-http_send_response(int fd, const struct request *req)
+http_send_response(int fd, const struct request *req, const struct server *s)
 {
 	enum status returnstatus;
 	struct in6_addr addr;
@@ -547,27 +547,27 @@ http_send_response(int fd, const struct request *req)
 
 	/* match vhost */
 	vhostmatch = NULL;
-	if (s.vhost) {
-		for (i = 0; i < s.vhost_len; i++) {
+	if (s->vhost) {
+		for (i = 0; i < s->vhost_len; i++) {
 			/* switch to vhost directory if there is a match */
-			if (!regexec(&s.vhost[i].re, req->field[REQ_HOST], 0,
+			if (!regexec(&(s->vhost[i].re), req->field[REQ_HOST], 0,
 			             NULL, 0)) {
-				if (chdir(s.vhost[i].dir) < 0) {
+				if (chdir(s->vhost[i].dir) < 0) {
 					return http_send_status(fd, (errno == EACCES) ?
 					                        S_FORBIDDEN : S_NOT_FOUND);
 				}
-				vhostmatch = s.vhost[i].chost;
+				vhostmatch = s->vhost[i].chost;
 				break;
 			}
 		}
-		if (i == s.vhost_len) {
+		if (i == s->vhost_len) {
 			return http_send_status(fd, S_NOT_FOUND);
 		}
 
 		/* if we have a vhost prefix, prepend it to the target */
-		if (s.vhost[i].prefix) {
+		if (s->vhost[i].prefix) {
 			if (esnprintf(tmptarget, sizeof(tmptarget), "%s%s",
-			              s.vhost[i].prefix, realtarget)) {
+			              s->vhost[i].prefix, realtarget)) {
 				return http_send_status(fd, S_REQUEST_TOO_LARGE);
 			}
 			memcpy(realtarget, tmptarget, sizeof(realtarget));
@@ -575,19 +575,19 @@ http_send_response(int fd, const struct request *req)
 	}
 
 	/* apply target prefix mapping */
-	for (i = 0; i < s.map_len; i++) {
-		len = strlen(s.map[i].from);
-		if (!strncmp(realtarget, s.map[i].from, len)) {
+	for (i = 0; i < s->map_len; i++) {
+		len = strlen(s->map[i].from);
+		if (!strncmp(realtarget, s->map[i].from, len)) {
 			/* match canonical host if vhosts are enabled and
 			 * the mapping specifies a canonical host */
-			if (s.vhost && s.map[i].chost &&
-			    strcmp(s.map[i].chost, vhostmatch)) {
+			if (s->vhost && s->map[i].chost &&
+			    strcmp(s->map[i].chost, vhostmatch)) {
 				continue;
 			}
 
 			/* swap out target prefix */
 			if (esnprintf(tmptarget, sizeof(tmptarget), "%s%s",
-			              s.map[i].to, realtarget + len)) {
+			              s->map[i].to, realtarget + len)) {
 				return http_send_status(fd, S_REQUEST_TOO_LARGE);
 			}
 			memcpy(realtarget, tmptarget, sizeof(realtarget));
@@ -628,7 +628,7 @@ http_send_response(int fd, const struct request *req)
 	}
 
 	/* redirect if targets differ, host is non-canonical or we prefixed */
-	if (strcmp(req->target, realtarget) || (s.vhost && vhostmatch &&
+	if (strcmp(req->target, realtarget) || (s->vhost && vhostmatch &&
 	    strcmp(req->field[REQ_HOST], vhostmatch))) {
 		res.status = S_MOVED_PERMANENTLY;
 
@@ -636,14 +636,14 @@ http_send_response(int fd, const struct request *req)
 		encode(realtarget, tmptarget);
 
 		/* determine target location */
-		if (s.vhost) {
+		if (s->vhost) {
 			/* absolute redirection URL */
 			targethost = req->field[REQ_HOST][0] ? vhostmatch ?
-			             vhostmatch : req->field[REQ_HOST] : s.host ?
-			             s.host : "localhost";
+			             vhostmatch : req->field[REQ_HOST] : s->host ?
+			             s->host : "localhost";
 
 			/* do we need to add a port to the Location? */
-			hasport = s.port && strcmp(s.port, "80");
+			hasport = s->port && strcmp(s->port, "80");
 
 			/* RFC 2732 specifies to use brackets for IPv6-addresses
 			 * in URLs, so we need to check if our host is one and
@@ -661,7 +661,7 @@ http_send_response(int fd, const struct request *req)
 			              ipv6host ? "[" : "",
 			              targethost,
 			              ipv6host ? "]" : "", hasport ? ":" : "",
-			              hasport ? s.port : "", tmptarget)) {
+			              hasport ? s->port : "", tmptarget)) {
 				return http_send_status(fd, S_REQUEST_TOO_LARGE);
 			}
 		} else {
@@ -679,16 +679,16 @@ http_send_response(int fd, const struct request *req)
 	if (S_ISDIR(st.st_mode)) {
 		/* append docindex to target */
 		if (esnprintf(realtarget, sizeof(realtarget), "%s%s",
-		              req->target, s.docindex)) {
+		              req->target, s->docindex)) {
 			return http_send_status(fd, S_REQUEST_TOO_LARGE);
 		}
 
 		/* stat the docindex, which must be a regular file */
 		if (stat(RELPATH(realtarget), &st) < 0 || !S_ISREG(st.st_mode)) {
-			if (s.listdirs) {
+			if (s->listdirs) {
 				/* remove index suffix and serve dir */
 				realtarget[strlen(realtarget) -
-				           strlen(s.docindex)] = '\0';
+				           strlen(s->docindex)] = '\0';
 				return resp_dir(fd, RELPATH(realtarget), req);
 			} else {
 				/* reject */

http.h

@@ -4,6 +4,8 @@
 
 #include <limits.h>
 
+#include "util.h"
+
 #define HEADER_MAX 4096
 #define FIELD_MAX 200
 
@@ -69,6 +71,7 @@ struct response {
 enum status http_send_header(int, const struct response *);
 enum status http_send_status(int, enum status);
 int http_get_request(int, struct request *);
-enum status http_send_response(int, const struct request *);
+enum status http_send_response(int, const struct request *,
+                               const struct server *);
 
 #endif /* HTTP_H */

main.c

@@ -23,7 +23,7 @@
 static char *udsname;
 
 static void
-serve(int infd, const struct sockaddr_storage *in_sa)
+serve(int infd, const struct sockaddr_storage *in_sa, const struct server *s)
 {
 	struct request req;
 	time_t t;
@@ -38,7 +38,7 @@ serve(int infd, const struct sockaddr_storage *in_sa)
 
 	/* handle request */
 	if (!(status = http_get_request(infd, &req))) {
-		status = http_send_response(infd, &req);
+		status = http_send_response(infd, &req, s);
 	}
 
 	/* write output to log */
@@ -177,6 +177,9 @@ main(int argc, char *argv[])
 	struct group *grp = NULL;
 	struct passwd *pwd = NULL;
 	struct rlimit rlim;
+	struct server s = {
+		.docindex = "index.html",
+	};
 	struct sockaddr_storage in_sa;
 	size_t i;
 	socklen_t in_sa_len;
@@ -190,13 +193,6 @@ main(int argc, char *argv[])
 	char *user = "nobody";
 	char *group = "nogroup";
 
-	s.host = s.port = NULL;
-	s.vhost = NULL;
-	s.map = NULL;
-	s.vhost_len = s.map_len = 0;
-	s.docindex = "index.html";
-	s.listdirs = 0;
-
 	ARGBEGIN {
 	case 'd':
 		servedir = EARGF(usage());
@@ -372,7 +368,7 @@ main(int argc, char *argv[])
 			/* fork and handle */
 			switch (fork()) {
 			case 0:
-				serve(infd, &in_sa);
+				serve(infd, &in_sa, &s);
 				exit(0);
 				break;
 			case -1:

util.c

@@ -16,7 +16,6 @@
 #include "util.h"
 
 char *argv0;
-struct server s;
 
 static void
 verr(const char *fmt, va_list ap)

util.h

@@ -23,7 +23,7 @@ struct map {
 	char *to;
 };
 
-extern struct server {
+struct server {
 	char *host;
 	char *port;
 	char *docindex;
@@ -32,7 +32,7 @@ extern struct server {
 	size_t vhost_len;
 	struct map *map;
 	size_t map_len;
-} s;
+};
 
 #undef MIN
 #define MIN(x,y)  ((x) < (y) ? (x) : (y))