From 0d6b5f522ed755aca8a85c005962fb03232b4c96 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Tue, 15 Dec 2020 18:55:27 +0100
Subject: [PATCH] config_font_parse(): return fail/success

---
 CHANGELOG.md |  1 +
 config.c     | 34 ++++++++++++++++++++++++++--------
 config.h     |  2 +-
 main.c       |  9 +++++++--
 4 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fa15a4c9..9569c3e9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -136,6 +136,7 @@ means foot can be PGO:d in e.g. sandboxed build scripts. See
   (e.g. `\E[38:5...m`)
 * Frames occasionally being rendered while application synchronized
   updates is in effect.
+* Handling of failures to parse the font specification string.
 
 
 ### Security
diff --git a/config.c b/config.c
index 085c9f7e..7434896a 100644
--- a/config.c
+++ b/config.c
@@ -534,8 +534,16 @@ parse_section_main(const char *key, const char *value, struct config *conf,
             /* Trim spaces, strictly speaking not necessary, but looks nice :) */
             while (*font != '\0' && isspace(*font))
                 font++;
-            if (*font != '\0')
-                tll_push_back(conf->fonts[idx], config_font_parse(font));
+            if (*font != '\0') {
+                struct config_font font_data;
+                if (!config_font_parse(font, &font_data)) {
+                    LOG_ERR("%s:%d: [default]: %s: invalid font specification",
+                            path, lineno, key);
+                    free(copy);
+                    return false;
+                }
+                tll_push_back(conf->fonts[idx], font_data);
+            }
         }
         free(copy);
     }
@@ -2083,8 +2091,14 @@ config_load(struct config *conf, const char *conf_path,
         conf->colors.selection_bg >> 24 == 0;
 
 out:
-    if (ret && tll_length(conf->fonts[0]) == 0)
-        tll_push_back(conf->fonts[0], config_font_parse("monospace"));
+    if (ret && tll_length(conf->fonts[0]) == 0) {
+        struct config_font font;
+        if (!config_font_parse("monospace", &font)) {
+            LOG_ERR("failed to load font 'monospace' - no fonts installed?");
+            ret = false;
+        } else
+            tll_push_back(conf->fonts[0], font);
+    }
 
     free(conf_file.path);
     if (conf_file.fd >= 0)
@@ -2131,10 +2145,12 @@ config_free(struct config conf)
     user_notifications_free(&conf.notifications);
 }
 
-struct config_font
-config_font_parse(const char *pattern)
+bool
+config_font_parse(const char *pattern, struct config_font *font)
 {
     FcPattern *pat = FcNameParse((const FcChar8 *)pattern);
+    if (pat == NULL)
+        return false;
 
     double pt_size = -1.0;
     FcPatternGetDouble(pat, FC_SIZE, 0, &pt_size);
@@ -2150,10 +2166,12 @@ config_font_parse(const char *pattern)
     char *stripped_pattern = (char *)FcNameUnparse(pat);
     FcPatternDestroy(pat);
 
-    return (struct config_font){
+    *font = (struct config_font){
         .pattern = stripped_pattern,
         .pt_size = pt_size,
-        .px_size = px_size};
+        .px_size = px_size
+    };
+    return true;
 }
 
 void
diff --git a/config.h b/config.h
index 9e5e8b4e..57af908e 100644
--- a/config.h
+++ b/config.h
@@ -191,5 +191,5 @@ bool config_load(
     user_notifications_t *initial_user_notifications, bool errors_are_fatal);
 void config_free(struct config conf);
 
-struct config_font config_font_parse(const char *pattern);
+bool config_font_parse(const char *pattern, struct config_font *font);
 void config_font_destroy(struct config_font *font);
diff --git a/main.c b/main.c
index 59ac9b61..094c242a 100644
--- a/main.c
+++ b/main.c
@@ -403,8 +403,13 @@ main(int argc, char *const *argv)
                 config_font_destroy(&it->item);
             tll_free(conf.fonts[i]);
         }
-        tll_foreach(conf_fonts, it)
-            tll_push_back(conf.fonts[0], config_font_parse(it->item));
+        tll_foreach(conf_fonts, it) {
+            struct config_font font;
+            if (!config_font_parse(it->item, &font)) {
+                LOG_ERR("%s: invalid font specification", it->item);
+            } else
+                tll_push_back(conf.fonts[0], font);
+        }
         tll_free(conf_fonts);
     }
     if (conf_width > 0 && conf_height > 0) {