printk: add %pM format specifier for MAC addresses
Add format specifiers for printing out six colon-separated bytes:
MAC addresses (%pM):
xx:xx:xx:xx:xx:xx
%#pM is also supported and omits the colon separators.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index a013bbc..0deaaaf 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -581,6 +581,23 @@
return string(buf, end, sym, field_width, precision, flags);
}
+static char *mac_address_string(char *buf, char *end, u8 *addr, int field_width,
+ int precision, int flags)
+{
+ char mac_addr[6 * 3]; /* (6 * 2 hex digits), 5 colons and trailing zero */
+ char *p = mac_addr;
+ int i;
+
+ for (i = 0; i < 6; i++) {
+ p = pack_hex_byte(p, addr[i]);
+ if (!(flags & SPECIAL) && i != 5)
+ *p++ = ':';
+ }
+ *p = '\0';
+
+ return string(buf, end, mac_addr, field_width, precision, flags & ~SPECIAL);
+}
+
/*
* Show a '%p' thing. A kernel extension is that the '%p' is followed
* by an extra set of alphanumeric characters that are extended format
@@ -592,6 +609,8 @@
* - 'S' For symbolic direct pointers
* - 'R' For a struct resource pointer, it prints the range of
* addresses (not the name nor the flags)
+ * - 'M' For a 6-byte MAC address, it prints the address in the
+ * usual colon-separated hex notation
*
* Note: The difference between 'S' and 'F' is that on ia64 and ppc64
* function pointers are really function descriptors, which contain a
@@ -607,6 +626,8 @@
return symbol_string(buf, end, ptr, field_width, precision, flags);
case 'R':
return resource_string(buf, end, ptr, field_width, precision, flags);
+ case 'M':
+ return mac_address_string(buf, end, ptr, field_width, precision, flags);
}
flags |= SMALL;
if (field_width == -1) {