microhttpd-util: use static buffer for static messages

Most of the messages we send do not require a allocating and
freeing a buffer, to optimize this by using const strings.

Also, rename respond_error to mhd_respond*, since it is used
not only for errors.

Make use of information from printf to avoid one extra call to
strlen.

4 files changed, 78 insertions, 68 deletions

diff --git a/src/journal/journal-gatewayd.c b/src/journal/journal-gatewayd.c
index d47b27ef7f..9a88676242 100644
--- a/src/journal/journal-gatewayd.c
+++ b/src/journal/journal-gatewayd.c
@@ -450,20 +450,20 @@ static int request_handler_entries(
 
         r = open_journal(m);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
+                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
 
         if (request_parse_accept(m, connection) < 0)
-                return respond_error(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse Accept header.\n");
+                return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse Accept header.\n");
 
         if (request_parse_range(m, connection) < 0)
-                return respond_error(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse Range header.\n");
+                return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse Range header.\n");
 
         if (request_parse_arguments(m, connection) < 0)
-                return respond_error(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse URL arguments.\n");
+                return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse URL arguments.\n");
 
         if (m->discrete) {
                 if (!m->cursor)
-                        return respond_error(connection, MHD_HTTP_BAD_REQUEST, "Discrete seeks require a cursor specification.\n");
+                        return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Discrete seeks require a cursor specification.\n");
 
                 m->n_entries = 1;
                 m->n_entries_set = true;
@@ -476,7 +476,7 @@ static int request_handler_entries(
         else if (m->n_skip < 0)
                 r = sd_journal_seek_tail(m->journal);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_BAD_REQUEST, "Failed to seek in journal.\n");
+                return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Failed to seek in journal.\n");
 
         response = MHD_create_response_from_callback(MHD_SIZE_UNKNOWN, 4*1024, request_reader_entries, m, NULL);
         if (!response)
@@ -612,14 +612,14 @@ static int request_handler_fields(
 
         r = open_journal(m);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
+                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
 
         if (request_parse_accept(m, connection) < 0)
-                return respond_error(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse Accept header.\n");
+                return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Failed to parse Accept header.\n");
 
         r = sd_journal_query_unique(m->journal, field);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_BAD_REQUEST, "Failed to query unique fields.\n");
+                return mhd_respond(connection, MHD_HTTP_BAD_REQUEST, "Failed to query unique fields.\n");
 
         response = MHD_create_response_from_callback(MHD_SIZE_UNKNOWN, 4*1024, request_reader_fields, m, NULL);
         if (!response)
@@ -678,10 +678,10 @@ static int request_handler_file(
 
         fd = open(path, O_RDONLY|O_CLOEXEC);
         if (fd < 0)
-                return respond_error(connection, MHD_HTTP_NOT_FOUND, "Failed to open file %s: %m\n", path);
+                return mhd_respondf(connection, MHD_HTTP_NOT_FOUND, "Failed to open file %s: %m\n", path);
 
         if (fstat(fd, &st) < 0)
-                return respond_error(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to stat file: %m\n");
+                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to stat file: %m\n");
 
         response = MHD_create_response_from_fd_at_offset(st.st_size, fd, 0);
         if (!response)
@@ -745,15 +745,15 @@ static int request_handler_machine(
 
         r = open_journal(m);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
+                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to open journal: %s\n", strerror(-r));
 
         r = sd_id128_get_machine(&mid);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine machine ID: %s\n", strerror(-r));
+                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine machine ID: %s\n", strerror(-r));
 
         r = sd_id128_get_boot(&bid);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine boot ID: %s\n", strerror(-r));
+                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine boot ID: %s\n", strerror(-r));
 
         hostname = gethostname_malloc();
         if (!hostname)
@@ -761,11 +761,11 @@ static int request_handler_machine(
 
         r = sd_journal_get_usage(m->journal, &usage);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine disk usage: %s\n", strerror(-r));
+                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine disk usage: %s\n", strerror(-r));
 
         r = sd_journal_get_cutoff_realtime_usec(m->journal, &cutoff_from, &cutoff_to);
         if (r < 0)
-                return respond_error(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine disk usage: %s\n", strerror(-r));
+                return mhd_respondf(connection, MHD_HTTP_INTERNAL_SERVER_ERROR, "Failed to determine disk usage: %s\n", strerror(-r));
 
         parse_env_file("/etc/os-release", NEWLINE, "PRETTY_NAME", &os_name, NULL);
 
@@ -822,8 +822,8 @@ static int request_handler(
         assert(method);
 
         if (!streq(method, "GET"))
-                return respond_error(connection, MHD_HTTP_METHOD_NOT_ACCEPTABLE,
-                                     "Unsupported method.\n");
+                return mhd_respond(connection, MHD_HTTP_METHOD_NOT_ACCEPTABLE,
+                                   "Unsupported method.\n");
 
 
         if (!*connection_cls) {
@@ -853,7 +853,7 @@ static int request_handler(
         if (streq(url, "/machine"))
                 return request_handler_machine(connection, *connection_cls);
 
-        return respond_error(connection, MHD_HTTP_NOT_FOUND, "Not found.\n");
+        return mhd_respond(connection, MHD_HTTP_NOT_FOUND, "Not found.\n");
 }
 
 static int help(void) {
diff --git a/src/journal/journal-remote.c b/src/journal/journal-remote.c
index 1a1ca2c480..78401839d5 100644
--- a/src/journal/journal-remote.c
+++ b/src/journal/journal-remote.c
@@ -411,7 +411,7 @@ static int process_http_upload(
                 if (r < 0) {
                         log_error("Failed to store received data of size %zu: %s",
                                   *upload_data_size, strerror(-r));
-                        return respond_oom_internal(connection);
+                        return mhd_respond_oom(connection);
                 }
                 *upload_data_size = 0;
         } else
@@ -425,8 +425,8 @@ static int process_http_upload(
                         break;
                 else if (r < 0) {
                         log_warning("Failed to process data for connection %p", connection);
-                        return respond_error(connection, MHD_HTTP_UNPROCESSABLE_ENTITY,
-                                             "Processing failed: %s", strerror(-r));
+                        return mhd_respondf(connection, MHD_HTTP_UNPROCESSABLE_ENTITY,
+                                            "Processing failed: %s", strerror(-r));
                 }
         }
 
@@ -437,11 +437,11 @@ static int process_http_upload(
 
         if (source_non_empty(source)) {
                 log_warning("EOF reached with incomplete data");
-                return respond_error(connection, MHD_HTTP_EXPECTATION_FAILED,
-                                     "Trailing data not processed.");
+                return mhd_respond(connection, MHD_HTTP_EXPECTATION_FAILED,
+                                   "Trailing data not processed.");
         }
 
-        return respond_error(connection, MHD_HTTP_ACCEPTED, "OK.\n");
+        return mhd_respond(connection, MHD_HTTP_ACCEPTED, "OK.\n");
 };
 
 static int request_handler(
@@ -470,19 +470,19 @@ static int request_handler(
                                            *connection_cls);
 
         if (!streq(method, "POST"))
-                return respond_error(connection, MHD_HTTP_METHOD_NOT_ACCEPTABLE,
-                                     "Unsupported method.\n");
+                return mhd_respond(connection, MHD_HTTP_METHOD_NOT_ACCEPTABLE,
+                                   "Unsupported method.\n");
 
         if (!streq(url, "/upload"))
-                return respond_error(connection, MHD_HTTP_NOT_FOUND,
-                                     "Not found.\n");
+                return mhd_respond(connection, MHD_HTTP_NOT_FOUND,
+                                   "Not found.\n");
 
         header = MHD_lookup_connection_value(connection,
                                              MHD_HEADER_KIND, "Content-Type");
         if (!header || !streq(header, "application/vnd.fdo.journal"))
-                return respond_error(connection, MHD_HTTP_UNSUPPORTED_MEDIA_TYPE,
-                                     "Content-Type: application/vnd.fdo.journal"
-                                     " is required.\n");
+                return mhd_respond(connection, MHD_HTTP_UNSUPPORTED_MEDIA_TYPE,
+                                   "Content-Type: application/vnd.fdo.journal"
+                                   " is required.\n");
 
         if (trust_pem) {
                 r = check_permissions(connection, &code);
diff --git a/src/journal/microhttpd-util.c b/src/journal/microhttpd-util.c
index f7f12e1a8e..250be93dbe 100644
--- a/src/journal/microhttpd-util.c
+++ b/src/journal/microhttpd-util.c
@@ -48,31 +48,45 @@ void microhttpd_logger(void *arg, const char *fmt, va_list ap) {
 }
 
 
-int respond_oom_internal(struct MHD_Connection *connection) {
-        const char *m = "Out of memory.\n";
-
+static int mhd_respond_internal(struct MHD_Connection *connection,
+                                enum MHD_RequestTerminationCode code,
+                                char *buffer,
+                                size_t size,
+                                enum MHD_ResponseMemoryMode mode) {
         struct MHD_Response *response;
-        int ret;
+        int r;
 
         assert(connection);
 
-        response = MHD_create_response_from_buffer(strlen(m), (char*) m, MHD_RESPMEM_PERSISTENT);
+        response = MHD_create_response_from_buffer(size, buffer, mode);
         if (!response)
                 return MHD_NO;
 
+        log_debug("Queing response %u: %s", code, buffer);
         MHD_add_response_header(response, "Content-Type", "text/plain");
-        ret = MHD_queue_response(connection, MHD_HTTP_SERVICE_UNAVAILABLE, response);
+        r = MHD_queue_response(connection, code, response);
         MHD_destroy_response(response);
 
-        return ret;
+        return r;
 }
 
-_printf_(3,4)
-int respond_error(struct MHD_Connection *connection,
-                  unsigned code,
-                  const char *format, ...) {
+int mhd_respond(struct MHD_Connection *connection,
+                enum MHD_RequestTerminationCode code,
+                const char *message) {
+
+        return mhd_respond_internal(connection, code,
+                                    (char*) message, strlen(message),
+                                    MHD_RESPMEM_PERSISTENT);
+}
+
+int mhd_respond_oom(struct MHD_Connection *connection) {
+        return mhd_respond(connection, MHD_HTTP_SERVICE_UNAVAILABLE,  "Out of memory.\n");
+}
+
+int mhd_respondf(struct MHD_Connection *connection,
+                 enum MHD_RequestTerminationCode code,
+                 const char *format, ...) {
 
-        struct MHD_Response *response;
         char *m;
         int r;
         va_list ap;
@@ -87,17 +101,9 @@ int respond_error(struct MHD_Connection *connection,
         if (r < 0)
                 return respond_oom(connection);
 
-        response = MHD_create_response_from_buffer(strlen(m), m, MHD_RESPMEM_MUST_FREE);
-        if (!response) {
+        r = mhd_respond_internal(connection, code, m, r, MHD_RESPMEM_MUST_FREE);
+        if (r == MHD_NO)
                 free(m);
-                return respond_oom(connection);
-        }
-
-        log_debug("Queing response %u: %s", code, m);
-        MHD_add_response_header(response, "Content-Type", "text/plain");
-        r = MHD_queue_response(connection, code, response);
-        MHD_destroy_response(response);
-
         return r;
 }
 
@@ -229,8 +235,8 @@ int check_permissions(struct MHD_Connection *connection, int *code) {
                                      MHD_CONNECTION_INFO_GNUTLS_SESSION);
         if (!ci) {
                 log_error("MHD_get_connection_info failed: session is unencrypted");
-                *code = respond_error(connection, MHD_HTTP_FORBIDDEN,
-                                      "Encrypted connection is required");
+                *code = mhd_respond(connection, MHD_HTTP_FORBIDDEN,
+                                    "Encrypted connection is required");
                 return -EPERM;
         }
         session = ci->tls_session;
@@ -238,15 +244,15 @@ int check_permissions(struct MHD_Connection *connection, int *code) {
 
         r = get_client_cert(session, &client_cert);
         if (r < 0) {
-                *code = respond_error(connection, MHD_HTTP_UNAUTHORIZED,
-                                      "Authorization through certificate is required");
+                *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
+                                    "Authorization through certificate is required");
                 return -EPERM;
         }
 
         r = get_auth_dn(client_cert, &buf);
         if (r < 0) {
-                *code = respond_error(connection, MHD_HTTP_UNAUTHORIZED,
-                                      "Failed to determine distinguished name from certificate");
+                *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
+                                    "Failed to determine distinguished name from certificate");
                 return -EPERM;
         }
 
@@ -255,8 +261,8 @@ int check_permissions(struct MHD_Connection *connection, int *code) {
         r = verify_cert_authorized(session);
         if (r < 0) {
                 log_warning("Client is not authorized");
-                *code = respond_error(connection, MHD_HTTP_UNAUTHORIZED,
-                                      "Client certificate not signed by recognized authority");
+                *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
+                                    "Client certificate not signed by recognized authority");
         }
         return r;
 }
diff --git a/src/journal/microhttpd-util.h b/src/journal/microhttpd-util.h
index cd14ac4dcf..df4d003eb9 100644
--- a/src/journal/microhttpd-util.h
+++ b/src/journal/microhttpd-util.h
@@ -28,14 +28,18 @@
 
 void microhttpd_logger(void *arg, const char *fmt, va_list ap) _printf_(2, 0);
 
-int respond_oom_internal(struct MHD_Connection *connection);
-
 /* respond_oom() must be usable with return, hence this form. */
-#define respond_oom(connection) log_oom(), respond_oom_internal(connection)
+#define respond_oom(connection) log_oom(), mhd_respond_oom(connection)
+
+int mhd_respondf(struct MHD_Connection *connection,
+                 unsigned code,
+                 const char *format, ...) _printf_(3,4);
+
+int mhd_respond(struct MHD_Connection *connection,
+                unsigned code,
+                const char *message);
 
-int respond_error(struct MHD_Connection *connection,
-                  unsigned code,
-                  const char *format, ...);
+int mhd_respond_oom(struct MHD_Connection *connection);
 
 int check_permissions(struct MHD_Connection *connection, int *code);