2 files changed, 78 insertions, 0 deletions

diff --git a/FICS/settings.cpp b/FICS/settings.cpp
index 2541759..fac35bb 100644
--- a/FICS/settings.cpp
+++ b/FICS/settings.cpp
@@ -94,6 +94,80 @@ install_setting(const char *name, const char *value)
 	return ENOENT;
 }
 
+bool
+is_valid_hostname(const char *p_str, err_reason_t *p_reason)
+{
+	const char	legal_index[] =
+	    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	    "abcdefghijklmnopqrstuvwxyz"
+	    "0123456789-.";
+	const size_t	HOST_MIN = 3;
+	const size_t	HOST_MAX = 253;
+	size_t		len = 0;
+
+	if (p_str == nullptr || strcmp(p_str, "") == 0) {
+		strlcpy(p_reason->data, "no input", sizeof p_reason->data);
+		return false;
+	} else if ((len = strlen(p_str)) < HOST_MIN) {
+		snprintf(p_reason->data, sizeof p_reason->data, "hostname too "
+		    "short (%zu): min=%zu", len, HOST_MIN);
+		return false;
+	} else if (len > HOST_MAX) {
+		snprintf(p_reason->data, sizeof p_reason->data, "hostname too "
+		    "long (%zu): max=%zu", len, HOST_MAX);
+		return false;
+	} else if (strstr(p_str, "..")) {
+		strlcpy(p_reason->data, "dot followed by dot",
+		    sizeof p_reason->data);
+		return false;
+	}
+
+	for (const char *cp = p_str; *cp != '\0'; cp++) {
+		if (strchr(legal_index, *cp) == nullptr) {
+			snprintf(p_reason->data, sizeof p_reason->data,
+			    "invalid chars found: first was '%c'", *cp);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool
+is_valid_username(const char *p_str, err_reason_t *p_reason)
+{
+	const char	legal_index[] =
+	    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	    "abcdefghijklmnopqrstuvwxyz"
+	    "0123456789_-";
+	const size_t	USER_MIN = 2;
+	const size_t	USER_MAX = 30;
+	size_t		len = 0;
+
+	if (p_str == nullptr || strcmp(p_str, "") == 0) {
+		strlcpy(p_reason->data, "no input", sizeof p_reason->data);
+		return false;
+	} else if ((len = strlen(p_str)) < USER_MIN) {
+		snprintf(p_reason->data, sizeof p_reason->data, "username too "
+		    "short (%zu): min=%zu", len, USER_MIN);
+		return false;
+	} else if (len > USER_MAX) {
+		snprintf(p_reason->data, sizeof p_reason->data, "username too "
+		    "long (%zu): max=%zu", len, USER_MAX);
+		return false;
+	}
+
+	for (const char *cp = p_str; *cp != '\0'; cp++) {
+		if (strchr(legal_index, *cp) == nullptr) {
+			snprintf(p_reason->data, sizeof p_reason->data,
+			    "invalid chars found: first was '%c'", *cp);
+			return false;
+		}
+	}
+
+	return true;
+}
+
 const char *
 settings_get(const char *set_name)
 {
diff --git a/FICS/settings.h b/FICS/settings.h
index 9dcf7dc..bfc8cf3 100644
--- a/FICS/settings.h
+++ b/FICS/settings.h
@@ -3,6 +3,8 @@
 
 #include "common.h"
 
+#include <stdbool.h>
+
 typedef struct {
 	char data[400];
 } err_reason_t;
@@ -11,6 +13,8 @@ __FICS_BEGIN_DECLS
 void		 settings_init(void);
 void		 settings_deinit(void);
 
+bool		 is_valid_hostname(const char *, err_reason_t *);
+bool		 is_valid_username(const char *, err_reason_t *);
 const char	*settings_get(const char *set_name);
 void		 settings_read_conf(const char *path);
 __FICS_END_DECLS