From 31550a16a5d2af859e8a11839e8c6c6c9c92dfa7 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Mon, 30 Jul 2012 14:40:27 -0700 Subject: vsprintf: add support of '%*ph[CDN]' 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] %*phC\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 Cc: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/vsprintf.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) (limited to 'lib/vsprintf.c') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 225aa683e17..0e337541f00 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -654,6 +654,50 @@ char *resource_string(char *buf, char *end, struct resource *res, return string(buf, end, sym, spec); } +static noinline_for_stack +char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec, + const char *fmt) +{ + int i, len = 1; /* if we pass '%ph[CDN]', field witdh remains + negative value, fallback to the default */ + char separator; + + if (spec.field_width == 0) + /* nothing to print */ + return buf; + + if (ZERO_OR_NULL_PTR(addr)) + /* NULL pointer */ + return string(buf, end, NULL, spec); + + switch (fmt[1]) { + case 'C': + separator = ':'; + break; + case 'D': + separator = '-'; + break; + case 'N': + separator = 0; + break; + default: + separator = ' '; + break; + } + + if (spec.field_width > 0) + len = min_t(int, spec.field_width, 64); + + for (i = 0; i < len && buf < end - 1; i++) { + buf = hex_byte_pack(buf, addr[i]); + + if (buf < end && separator && i != len - 1) + *buf++ = separator; + } + + return buf; +} + static noinline_for_stack char *mac_address_string(char *buf, char *end, u8 *addr, struct printf_spec spec, const char *fmt) @@ -974,6 +1018,13 @@ int kptr_restrict __read_mostly; * correctness of the format string and va_list arguments. * - 'K' For a kernel pointer that should be hidden from unprivileged users * - 'NF' For a netdev_features_t + * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with + * a certain separator (' ' by default): + * C colon + * D dash + * N no separator + * The maximum supported length is 64 bytes of the input. Consider + * to use print_hex_dump() for the larger input. * * Note: The difference between 'S' and 'F' is that on ia64 and ppc64 * function pointers are really function descriptors, which contain a @@ -1007,6 +1058,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'R': case 'r': return resource_string(buf, end, ptr, spec, fmt); + case 'h': + return hex_string(buf, end, ptr, spec, fmt); case 'M': /* Colon separated: 00:01:02:03:04:05 */ case 'm': /* Contiguous: 000102030405 */ /* [mM]F (FDDI) */ @@ -1296,6 +1349,8 @@ qualifier: * %pI6c print an IPv6 address as specified by RFC 5952 * %pU[bBlL] print a UUID/GUID in big or little 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 * * ** Please update Documentation/printk-formats.txt when making changes ** -- cgit v1.2.3-70-g09d2