There are many places in the kernel where the drivers print small buffers as a hex string. This patch adds a support of the variable width buffer to print it as a hex string with a delimiter. The idea came from Pavel Roskin here: http://www.digipedia.pl/usenet/thread/18835/17449/ Sample output of pr_info("buf[%d:%d] %*pM\n", from, len, len, &buf[from]); could be look like this: [ 0.726130] buf[51:8] e8:16:b6:ef:e3:74:45:6e [ 0.750736] buf[59:15] 31:81:b8:3f:35:49:06:ae:df:32:06:05:4a:af:55 [ 0.757602] buf[17:5] ac:16:d5:2c:ef Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> --- Documentation/printk-formats.txt | 5 ++++ lib/vsprintf.c | 49 ++++++++++++++++++++++++++------------ 2 files changed, 39 insertions(+), 15 deletions(-) diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt index 90ff4d7..3ae3d32 100644 --- a/Documentation/printk-formats.txt +++ b/Documentation/printk-formats.txt @@ -73,6 +73,11 @@ MAC/FDDI addresses: specifier to use reversed byte order suitable for visual interpretation of Bluetooth addresses which are in the little endian order. + Optional usage of all of the above is to specify variable length via + putting '*' into the specificator ('%*p[Mm][FR]'). In this case it will + print up to 64 bytes of the input as a hex string with certain + separator. For larger buffers consider to use print_hex_dump(). + IPv4 addresses: %pI4 1.2.3.4 diff --git a/lib/vsprintf.c b/lib/vsprintf.c index c65f5d4..ef4bbd2 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -655,12 +655,13 @@ char *resource_string(char *buf, char *end, struct resource *res, } static noinline_for_stack -char *mac_address_string(char *buf, char *end, u8 *addr, - struct printf_spec spec, const char *fmt) +char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec, + const char *fmt) { - char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")]; - char *p = mac_addr; - int i; + char hex_str[8*3+1]; /* support up to 8 bytes to print */ + int len = 6; /* default length is 6 bytes */ + char *p; + int i = 0, j; char separator; bool reversed = false; @@ -678,18 +679,31 @@ char *mac_address_string(char *buf, char *end, u8 *addr, break; } - for (i = 0; i < 6; i++) { - if (reversed) - p = hex_byte_pack(p, addr[5 - i]); - else - p = hex_byte_pack(p, addr[i]); + if (spec.field_width > 0) + len = min_t(int, spec.field_width, 64); + + while (i < len) { + p = hex_str; + for (j = 0; j < 8 && i < len; j++) { + if (reversed) + p = hex_byte_pack(p, addr[len - 1 - i]); + else + p = hex_byte_pack(p, addr[i]); + + if (fmt[0] == 'M' && i != len - 1) + *p++ = separator; + i++; + } + *p = '\0'; - if (fmt[0] == 'M' && i != 5) - *p++ = separator; + for (p = hex_str; *p != '\0'; p++) { + if (buf < end) + *buf = *p; + ++buf; + } } - *p = '\0'; - return string(buf, end, mac_addr, spec); + return buf; } static noinline_for_stack @@ -947,6 +961,9 @@ int kptr_restrict __read_mostly; * - 'MF' For a 6-byte MAC FDDI address, it prints the address * with a dash-separated hex notation * - '[mM]R For a 6-byte MAC address, Reverse order (Bluetooth) + * Optional usage is %*p[Mn][FR] with variable length to print. It + * supports up to 64 bytes of the input. Consider to use print_hex_dump() + * for the larger input. * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way * IPv4 uses dot-separated decimal without leading 0's (1.2.3.4) * IPv6 uses colon separated network-order 16 bit hex with leading 0's @@ -1011,7 +1028,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'm': /* Contiguous: 000102030405 */ /* [mM]F (FDDI) */ /* [mM]R (Reverse order; Bluetooth) */ - return mac_address_string(buf, end, ptr, spec, fmt); + return hex_string(buf, end, ptr, spec, fmt); case 'I': /* Formatted IP supported * 4: 1.2.3.4 * 6: 0001:0203:...:0708 @@ -1291,6 +1308,8 @@ qualifier: * %pMF output a 6-byte MAC address with dashes * %pm output a 6-byte MAC address without colons * %pmR output a 6-byte MAC address without colons in reversed order + * %*p[Mm][FR] a variable-length hex string with a separator (supports up to 64 + * bytes of the input) * %pI4 print an IPv4 address without leading zeros * %pi4 print an IPv4 address with leading zeros * %pI6 print an IPv6 address with colons -- 1.7.10 -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
