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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2012-07-30 14:40:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 17:25:14 -0700
commit31550a16a5d2af859e8a11839e8c6c6c9c92dfa7 (patch)
treeb38c5921bfeecdfc24e3146b15e21360a490e19e /lib/vsprintf.c
parent3715c5309f6d175c3053672b73fd4f73be16fd07 (diff)
downloadlinux-31550a16a5d2af859e8a11839e8c6c6c9c92dfa7.tar.gz
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 <andriy.shevchenko@linux.intel.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/vsprintf.c')
-rw-r--r--lib/vsprintf.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 225aa683e17..0e337541f00 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -655,6 +655,50 @@ char *resource_string(char *buf, char *end, struct resource *res,
}
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 **