The Bluetooth UUID is used in big endian reversed order. Add new
modifier to print a UUID in big endian, but where the input byte
stream is actually in reversed order.
This is similar to %pMR that allows to print a MAC address in
reversed order since that is how the Bluetooth BD_ADDR is
actually represented in a byte stream.
Signed-off-by: Marcel Holtmann <mar...@holtmann.org>
---
v2: Allow combinations of %pUlr etc.
Documentation/printk-formats.txt | 6 ++++++
lib/vsprintf.c | 40 ++++++++++++++++++++++++++++------------
2 files changed, 34 insertions(+), 12 deletions(-)
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 445ad74..1fd0e43 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -159,12 +159,18 @@ UUID/GUID addresses:
%pUB 00010203-0405-0607-0809-0A0B0C0D0E0F
%pUl 03020100-0504-0706-0809-0a0b0c0e0e0f
%pUL 03020100-0504-0706-0809-0A0B0C0E0E0F
+ %pUr 0f0e0d0c-0b0a-0908-0706-050403020100
+ %pUR 0F0E0D0C-0B0A-0908-0706-050403020100
For printing 16-byte UUID/GUIDs addresses. The additional 'l', 'L',
'b' and 'B' specifiers are used to specify a little endian order in
lower ('l') or upper case ('L') hex characters - and big endian order
in lower ('b') or upper case ('B') hex characters.
+ The additional 'r' and 'R' specifiers are used to specify reversed
+ big endian order in either lower ('r') or upper case ('R') hex
+ characters. This is useful for Bluetooth UUID addresses.
+
Where no additional specifiers are used the default little endian
order with lower case hex characters will be printed.
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 26559bd..d0f9188 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1106,20 +1106,32 @@ char *uuid_string(char *buf, char *end, const u8 *addr,
static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
const u8 *index = be;
bool uc = false;
+ bool reversed = false;
- switch (*(++fmt)) {
- case 'L':
- uc = true; /* fall-through */
- case 'l':
- index = le;
- break;
- case 'B':
- uc = true;
- break;
+ while (isalpha(*++fmt)) {
+ switch (*fmt) {
+ case 'L':
+ uc = true; /* fall-through */
+ case 'l':
+ index = le;
+ break;
+ case 'B':
+ uc = true;
+ break;
+ case 'R':
+ uc = true; /* fall-through */
+ case 'r':
+ reversed = true;
+ break;
+ }
}
for (i = 0; i < 16; i++) {
- p = hex_byte_pack(p, addr[index[i]]);
+ if (reversed)
+ p = hex_byte_pack(p, addr[index[15 - i]]);
+ else
+ p = hex_byte_pack(p, addr[index[i]]);
+
switch (i) {
case 3:
case 5:
@@ -1199,10 +1211,14 @@ int kptr_restrict __read_mostly;
* B big endian UPPER case hex
* l little endian lower case hex
* L little endian UPPER case hex
+ * r big endian lower case hex, reverse order (Bluetooth)
+ * R big endian UPPER case hex, reverse order (Bluetooth)
* big endian output byte order is:
* [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
* little endian output byte order is:
* [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
+ * big endian, reverse order output byte order is:
+ * [15][14][13][12]-[11][10]-[9][8]-[7][6]-[5][4][3][2][1][0]
* - 'V' For a struct va_format which contains a format string * and va_list *,
* call vsnprintf(->format, *->va_list).
* Implements a "recursive vsnprintf".
@@ -1572,8 +1588,8 @@ qualifier:
* %pI6c print an IPv6 address as specified by RFC 5952
* %pIS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
* %piS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
- * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
- * case.
+ * %pU[bBlLrR] print a UUID/GUID in big or little endian or reversed order
+ * big endian using lower or upper case.
* %*ph[CDN] a variable-length hex string with a separator (supports up to 64
* bytes of the input)
* %n is ignored
--
1.8.3.1
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