Codechange: validate that "max" value of settings fit in their storage

This is an easy mistake to make, so protect us against making such
mistakes, by validating it doesn't happen.

9 files changed, 122 insertions, 57 deletions

diff --git a/src/settings_type.h b/src/settings_type.h
index f2c591f64..433e8d535 100644
--- a/src/settings_type.h
+++ b/src/settings_type.h
@@ -21,6 +21,15 @@
 #include "zoom_type.h"
 #include "openttd.h"
 
+/* Used to validate sizes of "max" value in settings. */
+const size_t MAX_SLE_UINT8 = UINT8_MAX;
+const size_t MAX_SLE_UINT16 = UINT16_MAX;
+const size_t MAX_SLE_UINT32 = UINT32_MAX;
+const size_t MAX_SLE_UINT = UINT_MAX;
+const size_t MAX_SLE_INT8 = INT8_MAX;
+const size_t MAX_SLE_INT16 = INT16_MAX;
+const size_t MAX_SLE_INT32 = INT32_MAX;
+const size_t MAX_SLE_INT = INT_MAX;
 
 /** Settings profiles and highscore tables. */
 enum SettingsProfile {
diff --git a/src/settingsgen/settingsgen.cpp b/src/settingsgen/settingsgen.cpp
index ac3a2a85a..8dd9ff6f4 100644
--- a/src/settingsgen/settingsgen.cpp
+++ b/src/settingsgen/settingsgen.cpp
@@ -186,11 +186,13 @@ struct SettingsIniFile : IniLoadFile {
 };
 
 OutputStore _stored_output; ///< Temporary storage of the output, until all processing is done.
+OutputStore _post_amble_output; ///< Similar to _stored_output, but for the post amble.
 
-static const char *PREAMBLE_GROUP_NAME  = "pre-amble";  ///< Name of the group containing the pre amble.
+static const char *PREAMBLE_GROUP_NAME  = "pre-amble"; ///< Name of the group containing the pre amble.
 static const char *POSTAMBLE_GROUP_NAME = "post-amble"; ///< Name of the group containing the post amble.
-static const char *TEMPLATES_GROUP_NAME = "templates";  ///< Name of the group containing the templates.
-static const char *DEFAULTS_GROUP_NAME  = "defaults";   ///< Name of the group containing default values for the template variables.
+static const char *TEMPLATES_GROUP_NAME = "templates"; ///< Name of the group containing the templates.
+static const char *VALIDATION_GROUP_NAME = "validation"; ///< Name of the group containing the validation statements.
+static const char *DEFAULTS_GROUP_NAME  = "defaults"; ///< Name of the group containing default values for the template variables.
 
 /**
  * Load the INI file.
@@ -240,16 +242,83 @@ static const char *FindItemValue(const char *name, IniGroup *grp, IniGroup *defa
 }
 
 /**
+ * Parse a single entry via a template and output this.
+ * @param item The template to use for the output.
+ * @param grp Group current being used for template rendering.
+ * @param default_grp Default values for items not set in @grp.
+ * @param output Output to use for result.
+ */
+static void DumpLine(IniItem *item, IniGroup *grp, IniGroup *default_grp, OutputStore &output)
+{
+	static const int MAX_VAR_LENGTH = 64;
+
+	/* Prefix with #if/#ifdef/#ifndef */
+	static const char * const pp_lines[] = {"if", "ifdef", "ifndef", nullptr};
+	int count = 0;
+	for (const char * const *name = pp_lines; *name != nullptr; name++) {
+		const char *condition = FindItemValue(*name, grp, default_grp);
+		if (condition != nullptr) {
+			output.Add("#", 1);
+			output.Add(*name);
+			output.Add(" ", 1);
+			output.Add(condition);
+			output.Add("\n", 1);
+			count++;
+		}
+	}
+
+	/* Output text of the template, except template variables of the form '$[_a-z0-9]+' which get replaced by their value. */
+	const char *txt = item->value->c_str();
+	while (*txt != '\0') {
+		if (*txt != '$') {
+			output.Add(txt, 1);
+			txt++;
+			continue;
+		}
+		txt++;
+		if (*txt == '$') { // Literal $
+			output.Add(txt, 1);
+			txt++;
+			continue;
+		}
+
+		/* Read variable. */
+		char variable[MAX_VAR_LENGTH];
+		int i = 0;
+		while (i < MAX_VAR_LENGTH - 1) {
+			if (!(txt[i] == '_' || (txt[i] >= 'a' && txt[i] <= 'z') || (txt[i] >= '0' && txt[i] <= '9'))) break;
+			variable[i] = txt[i];
+			i++;
+		}
+		variable[i] = '\0';
+		txt += i;
+
+		if (i > 0) {
+			/* Find the text to output. */
+			const char *valitem = FindItemValue(variable, grp, default_grp);
+			if (valitem != nullptr) output.Add(valitem);
+		} else {
+			output.Add("$", 1);
+		}
+	}
+	output.Add("\n", 1); // \n after the expanded template.
+	while (count > 0) {
+		output.Add("#endif\n");
+		count--;
+	}
+}
+
+/**
  * Output all non-special sections through the template / template variable expansion system.
  * @param ifile Loaded INI data.
  */
 static void DumpSections(IniLoadFile *ifile)
 {
-	static const int MAX_VAR_LENGTH = 64;
-	static const char * const special_group_names[] = {PREAMBLE_GROUP_NAME, POSTAMBLE_GROUP_NAME, DEFAULTS_GROUP_NAME, TEMPLATES_GROUP_NAME, nullptr};
+	static const char * const special_group_names[] = {PREAMBLE_GROUP_NAME, POSTAMBLE_GROUP_NAME, DEFAULTS_GROUP_NAME, TEMPLATES_GROUP_NAME, VALIDATION_GROUP_NAME, nullptr};
 
 	IniGroup *default_grp = ifile->GetGroup(DEFAULTS_GROUP_NAME, false);
 	IniGroup *templates_grp  = ifile->GetGroup(TEMPLATES_GROUP_NAME, false);
+	IniGroup *validation_grp  = ifile->GetGroup(VALIDATION_GROUP_NAME, false);
 	if (templates_grp == nullptr) return;
 
 	/* Output every group, using its name as template name. */
@@ -263,61 +332,14 @@ static void DumpSections(IniLoadFile *ifile)
 			fprintf(stderr, "settingsgen: Warning: Cannot find template %s\n", grp->name.c_str());
 			continue;
 		}
+		DumpLine(template_item, grp, default_grp, _stored_output);
 
-		/* Prefix with #if/#ifdef/#ifndef */
-		static const char * const pp_lines[] = {"if", "ifdef", "ifndef", nullptr};
-		int count = 0;
-		for (const char * const *name = pp_lines; *name != nullptr; name++) {
-			const char *condition = FindItemValue(*name, grp, default_grp);
-			if (condition != nullptr) {
-				_stored_output.Add("#", 1);
-				_stored_output.Add(*name);
-				_stored_output.Add(" ", 1);
-				_stored_output.Add(condition);
-				_stored_output.Add("\n", 1);
-				count++;
+		if (validation_grp != nullptr) {
+			IniItem *validation_item = validation_grp->GetItem(grp->name, false); // Find template value.
+			if (validation_item != nullptr && validation_item->value.has_value()) {
+				DumpLine(validation_item, grp, default_grp, _post_amble_output);
 			}
 		}
-
-		/* Output text of the template, except template variables of the form '$[_a-z0-9]+' which get replaced by their value. */
-		const char *txt = template_item->value->c_str();
-		while (*txt != '\0') {
-			if (*txt != '$') {
-				_stored_output.Add(txt, 1);
-				txt++;
-				continue;
-			}
-			txt++;
-			if (*txt == '$') { // Literal $
-				_stored_output.Add(txt, 1);
-				txt++;
-				continue;
-			}
-
-			/* Read variable. */
-			char variable[MAX_VAR_LENGTH];
-			int i = 0;
-			while (i < MAX_VAR_LENGTH - 1) {
-				if (!(txt[i] == '_' || (txt[i] >= 'a' && txt[i] <= 'z') || (txt[i] >= '0' && txt[i] <= '9'))) break;
-				variable[i] = txt[i];
-				i++;
-			}
-			variable[i] = '\0';
-			txt += i;
-
-			if (i > 0) {
-				/* Find the text to output. */
-				const char *valitem = FindItemValue(variable, grp, default_grp);
-				if (valitem != nullptr) _stored_output.Add(valitem);
-			} else {
-				_stored_output.Add("$", 1);
-			}
-		}
-		_stored_output.Add("\n", 1); // \n after the expanded template.
-		while (count > 0) {
-			_stored_output.Add("#endif\n");
-			count--;
-		}
 	}
 }
 
@@ -476,6 +498,7 @@ int CDECL main(int argc, char *argv[])
 	}
 
 	_stored_output.Clear();
+	_post_amble_output.Clear();
 
 	for (int i = 0; i < mgo.numleft; i++) ProcessIniFile(mgo.argv[i]);
 
@@ -483,6 +506,7 @@ int CDECL main(int argc, char *argv[])
 	if (output_file == nullptr) {
 		CopyFile(before_file, stdout);
 		_stored_output.Write(stdout);
+		_post_amble_output.Write(stdout);
 		CopyFile(after_file, stdout);
 	} else {
 		static const char * const tmp_output = "tmp2.xxx";
@@ -494,6 +518,7 @@ int CDECL main(int argc, char *argv[])
 		}
 		CopyFile(before_file, fp);
 		_stored_output.Write(fp);
+		_post_amble_output.Write(fp);
 		CopyFile(after_file, fp);
 		fclose(fp);
 
diff --git a/src/table/company_settings.ini b/src/table/company_settings.ini
index e685ff6dc..eea2371fc 100644
--- a/src/table/company_settings.ini
+++ b/src/table/company_settings.ini
@@ -20,6 +20,9 @@ SDT_BOOL = SDT_BOOL($base, $var,        $flags, $guiflags, $def,
 SDT_VAR  =  SDT_VAR($base, $var, $type, $flags, $guiflags, $def, $min, $max, $interval, $str, $strhelp, $strval, $proc, $from, $to, $cat, $extra, $startup),
 SDT_END  = SDT_END()
 
+[validation]
+SDT_VAR = static_assert($max <= MAX_$type, "Maximum value for $base.$var exceeds storage size");
+
 [defaults]
 flags    = 0
 guiflags = SGF_PER_COMPANY
diff --git a/src/table/currency_settings.ini b/src/table/currency_settings.ini
index 7ff879964..c242c83a8 100644
--- a/src/table/currency_settings.ini
+++ b/src/table/currency_settings.ini
@@ -14,6 +14,9 @@ SDT_CHR = SDT_CHR($base, $var,        $flags, $guiflags, $def,
 SDT_STR = SDT_STR($base, $var, $type, $flags, $guiflags, $def,                        $str, $strhelp, $strval, $proc, $from, $to, $cat, $extra, $startup),
 SDT_END = SDT_END()
 
+[validation]
+SDT_VAR = static_assert($max <= MAX_$type, "Maximum value for $base.$var exceeds storage size");
+
 [defaults]
 flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
 guiflags = SGF_NONE
diff --git a/src/table/gameopt_settings.ini b/src/table/gameopt_settings.ini
index b85e11d9c..c4140f428 100644
--- a/src/table/gameopt_settings.ini
+++ b/src/table/gameopt_settings.ini
@@ -46,6 +46,13 @@ SDT_OMANY    =  SDT_OMANY($base, $var, $type, $flags, $guiflags, $def,       $ma
 SDT_VAR      =    SDT_VAR($base, $var, $type, $flags, $guiflags, $def, $min, $max,        $interval, $str, $strhelp, $strval, $proc, $from, $to,        $cat, $extra, $startup),
 SDT_END      = SDT_END()
 
+[validation]
+SDTG_VAR = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+SDTG_OMANY = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+SDTC_OMANY = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+SDT_OMANY = static_assert($max <= MAX_$type, "Maximum value for $base.$var exceeds storage size");
+SDT_VAR = static_assert($max <= MAX_$type, "Maximum value for $base.$var exceeds storage size");
+
 [defaults]
 flags    = 0
 guiflags = SGF_NONE
diff --git a/src/table/misc_settings.ini b/src/table/misc_settings.ini
index 3add5148f..9d2f76cc0 100644
--- a/src/table/misc_settings.ini
+++ b/src/table/misc_settings.ini
@@ -26,6 +26,10 @@ SDTG_BOOL  =  SDTG_BOOL($name,                 $flags, $guiflags, $var, $def,
 SDTG_VAR   =   SDTG_VAR($name, $type,          $flags, $guiflags, $var, $def, $min, $max, $interval,        $str, $strhelp, $strval, $proc, $from, $to, $cat, $extra, $startup),
 SDTG_END   = SDTG_END()
 
+[validation]
+SDTG_VAR = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+SDTG_OMANY = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+
 [defaults]
 flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
 guiflags = SGF_NONE
diff --git a/src/table/settings.ini b/src/table/settings.ini
index dd0ecfee5..b48ac6cd6 100644
--- a/src/table/settings.ini
+++ b/src/table/settings.ini
@@ -77,6 +77,14 @@ SDT_VAR    =    SDT_VAR($base, $var, $type, $flags, $guiflags, $def,       $min,
 SDT_NULL   =   SDT_NULL($length, $from, $to),
 SDT_END    = SDT_END()
 
+[validation]
+SDTG_VAR = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+SDTG_OMANY = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+SDTC_OMANY = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+SDTC_VAR = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+SDT_OMANY = static_assert($max <= MAX_$type, "Maximum value for $base.$var exceeds storage size");
+SDT_VAR = static_assert($max <= MAX_$type, "Maximum value for $base.$var exceeds storage size");
+
 [defaults]
 flags    = 0
 guiflags = SGF_NONE
diff --git a/src/table/win32_settings.ini b/src/table/win32_settings.ini
index 406e8dd8f..c3cc45014 100644
--- a/src/table/win32_settings.ini
+++ b/src/table/win32_settings.ini
@@ -18,6 +18,9 @@ SDTG_BOOL = SDTG_BOOL($name,        $flags, $guiflags, $var, $def,
 SDTG_VAR  =  SDTG_VAR($name, $type, $flags, $guiflags, $var, $def, $min, $max, $interval, $str, $strhelp, $strval, $proc, $from, $to, $cat, $extra, $startup),
 SDTG_END  = SDTG_END()
 
+[validation]
+SDTG_VAR = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
+
 [defaults]
 flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
 guiflags = SGF_NONE
diff --git a/src/table/window_settings.ini b/src/table/window_settings.ini
index e336d6447..fb252076c 100644
--- a/src/table/window_settings.ini
+++ b/src/table/window_settings.ini
@@ -14,6 +14,9 @@ SDT_BOOL = SDT_BOOL($base, $var,        $flags, $guiflags, $def,
 SDT_VAR  =  SDT_VAR($base, $var, $type, $flags, $guiflags, $def, $min, $max, $interval, $str, $strhelp, $strval, $proc, $from, $to, $cat, $extra, $startup),
 SDT_END  = SDT_END()
 
+[validation]
+SDT_VAR = static_assert($max <= MAX_$type, "Maximum value for $base.$var exceeds storage size");
+
 [defaults]
 base     = WindowDesc
 flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC