Messages in this thread Patch in this message | | | Subject | [RFC PATCHv3] printk: add %pM format specifier for MAC addresses | From | Harvey Harrison <> | Date | Mon, 27 Oct 2008 12:59:02 -0700 |
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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> --- Dave, this passes testing here, but I was wondering if perhaps it would be better to allow a length to be specified as well, which would allow:
%pM6 for mac addresses, etc as there seem a lot of places in kernel that print out a list of colon separated bytes of various lengths.
But if that was added, it may be more natural to call it %pB (bytes) %pW (words)
Then mac addresses would be %pB6 IPv6 addresses would be %pW8 (8 words)
It would be trivial to add, but maybe I'm overthinking this. In any event, this patch only adds %pM for mac addresses.
lib/vsprintf.c | 21 +++++++++++++++++++++ 1 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index a013bbc..2025305 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -581,6 +581,23 @@ static char *resource_string(char *buf, char *end, struct resource *res, int fie return string(buf, end, sym, field_width, precision, flags); } +static char *mac_address(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 @@ static char *resource_string(char *buf, char *end, struct resource *res, int fie * - '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 @@ static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field 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(buf, end, ptr, field_width, precision, flags); } flags |= SMALL; if (field_width == -1) { -- 1.6.0.3.729.g6ea410
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