[PATCH v4 1/5] x86/boot: Add strlcat() to compressed kernel

[Evgeniy Baskov <baskov@ispras.ru>]

strlcat() simplifies the code of command line
concatenation and reduces the probability of mistakes.

Signed-off-by: Evgeniy Baskov <baskov@ispras.ru>

diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c
index 81fc1eaa3229..6d74d31bf3d9 100644
--- a/arch/x86/boot/compressed/string.c
+++ b/arch/x86/boot/compressed/string.c
@@ -40,6 +40,25 @@ static void *____memcpy(void *dest, const void *src, size_t n)
 }
 #endif
 
+size_t strlcat(char *dest, const char *src, size_t count)
+{
+	size_t dsize = strlen(dest);
+	size_t len = strlen(src);
+	size_t res = dsize + len;
+
+	/* This would be a bug */
+	if (dsize >= count)
+		error("strlcat(): destination too big\n");
+
+	dest += dsize;
+	count -= dsize;
+	if (len >= count)
+		len = count-1;
+	memcpy(dest, src, len);
+	dest[len] = 0;
+	return res;
+}
+
 void *memset(void *s, int c, size_t n)
 {
 	int i;
diff --git a/arch/x86/purgatory/purgatory.c b/arch/x86/purgatory/purgatory.c
index 7558139920f8..65f0cedb65ae 100644
--- a/arch/x86/purgatory/purgatory.c
+++ b/arch/x86/purgatory/purgatory.c
@@ -57,3 +57,4 @@ void purgatory(void)
  * arch/x86/boot/compressed/string.c
  */
 void warn(const char *msg) {}
+void error(char *m) {}
-- 
2.36.1