text_file: allocate line buffers dynamically

Use a single GString buffer object in all functions loading the
database.  Enlarge it automatically for long lines.  This eliminates
the maximum line length for tag values.  There is still an upper limit
of 512 kB to prevent denial of service, but that's reasonable I guess.

1 files changed, 19 insertions, 19 deletions

diff --git a/src/database.c b/src/database.c
index 5a06dda98..dc0ef3686 100644
--- a/src/database.c
+++ b/src/database.c
@@ -23,6 +23,7 @@
 #include "song.h"
 #include "path.h"
 #include "stats.h"
+#include "text_file.h"
 #include "config.h"
 
 #include <glib.h>
@@ -256,7 +257,8 @@ db_load(GError **error)
 {
 	FILE *fp = NULL;
 	struct stat st;
-	char buffer[100];
+	GString *buffer = g_string_sized_new(1024);
+	char *line;
 	bool found_charset = false, found_version = false;
 	bool success;
 
@@ -270,50 +272,45 @@ db_load(GError **error)
 		g_set_error(error, db_quark(), errno,
 			    "Failed to open database file \"%s\": %s",
 			    database_path, strerror(errno));
+		g_string_free(buffer, true);
 		return false;
 	}
 
 	/* get initial info */
-	if (!fgets(buffer, sizeof(buffer), fp)) {
-		fclose(fp);
-		g_set_error(error, db_quark(), 0, "Unexpected end of file");
-		return false;
-	}
-
-	g_strchomp(buffer);
-
-	if (0 != strcmp(DIRECTORY_INFO_BEGIN, buffer)) {
+	line = read_text_line(fp, buffer);
+	if (line == NULL || strcmp(DIRECTORY_INFO_BEGIN, line) != 0) {
 		fclose(fp);
 		g_set_error(error, db_quark(), 0, "Database corrupted");
+		g_string_free(buffer, true);
 		return false;
 	}
 
-	while (fgets(buffer, sizeof(buffer), fp) &&
-	       !g_str_has_prefix(buffer, DIRECTORY_INFO_END)) {
-		g_strchomp(buffer);
-
-		if (g_str_has_prefix(buffer, DIRECTORY_MPD_VERSION)) {
+	while ((line = read_text_line(fp, buffer)) != NULL &&
+	       !g_str_has_prefix(line, DIRECTORY_INFO_END)) {
+		if (g_str_has_prefix(line, DIRECTORY_MPD_VERSION)) {
 			if (found_version) {
 				fclose(fp);
 				g_set_error(error, db_quark(), 0,
 					    "Duplicate version line");
+				g_string_free(buffer, true);
 				return false;
 			}
 
 			found_version = true;
-		} else if (g_str_has_prefix(buffer, DIRECTORY_FS_CHARSET)) {
+		} else if (g_str_has_prefix(line, DIRECTORY_FS_CHARSET)) {
 			const char *new_charset, *old_charset;
 
 			if (found_charset) {
 				fclose(fp);
 				g_set_error(error, db_quark(), 0,
 					    "Duplicate charset line");
+				g_string_free(buffer, true);
 				return false;
 			}
 
 			found_charset = true;
 
-			new_charset = &(buffer[strlen(DIRECTORY_FS_CHARSET)]);
+			new_charset = line + sizeof(DIRECTORY_FS_CHARSET) - 1;
 			old_charset = path_get_fs_charset();
 			if (old_charset != NULL
 			    && strcmp(new_charset, old_charset)) {
@@ -323,19 +320,22 @@ db_load(GError **error)
 					    "\"%s\" instead of \"%s\"; "
 					    "discarding database file",
 					    new_charset, old_charset);
+				g_string_free(buffer, true);
 				return false;
 			}
 		} else {
 			fclose(fp);
 			g_set_error(error, db_quark(), 0,
-				    "Malformed line: %s", buffer);
+				    "Malformed line: %s", line);
+			g_string_free(buffer, true);
 			return false;
 		}
 	}
 
 	g_debug("reading DB");
 
-	success = directory_load(fp, music_root, error);
+	success = directory_load(fp, music_root, buffer, error);
+	g_string_free(buffer, true);
 	while (fclose(fp) && errno == EINTR) ;
 
 	if (!success)