From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: [PATCH for-4.5 1/2] xen/vsprintf: Introduce %*ph extended format specifier for hex buffers Date: Fri, 26 Sep 2014 11:10:06 +0100 Message-ID: <1411726207-2689-2-git-send-email-andrew.cooper3@citrix.com> References: <1411726207-2689-1-git-send-email-andrew.cooper3@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1411726207-2689-1-git-send-email-andrew.cooper3@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Xen-devel Cc: Andrew Cooper , Keir Fraser , Jan Beulich , Tim Deegan List-Id: xen-devel@lists.xenproject.org This behaves in the same way as Linux. The 64 byte limit is arbitrary but long enough for practical purposes. Signed-off-by: Andrew Cooper CC: Keir Fraser CC: Jan Beulich CC: Tim Deegan CC: Konrad Rzeszutek Wilk --- docs/misc/printk-formats.txt | 6 ++++++ xen/common/vsprintf.c | 25 +++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/docs/misc/printk-formats.txt b/docs/misc/printk-formats.txt index 3b4323a..81b3651 100644 --- a/docs/misc/printk-formats.txt +++ b/docs/misc/printk-formats.txt @@ -18,3 +18,9 @@ Symbol/Function pointers: %pv Domain and vCPU ID from a 'struct vcpu *' (printed as "dv") + + +Raw buffer as hex string: + + %*ph Up to 64 characters, printed as "00 01 02 ... ff". Buffer length + expected via the field_width paramter. i.e. printk("%*ph", 8, buffer); diff --git a/xen/common/vsprintf.c b/xen/common/vsprintf.c index e68886a..4a7da1c 100644 --- a/xen/common/vsprintf.c +++ b/xen/common/vsprintf.c @@ -272,6 +272,31 @@ static char *pointer(char *str, char *end, const char **fmt_ptr, /* Custom %p suffixes. See XEN_ROOT/docs/misc/printk-formats.txt */ switch ( fmt[1] ) { + case 'h': /* Raw buffer as hex string. */ + { + /* + * User expected to provide an explicit count using %*. Bound between + * 0 and 64 bytes, defaulting to 0. + */ + unsigned i, nr_bytes = + ((field_width < 1) || (field_width > 64)) ? 0 : field_width; + const uint8_t *hex_buffer = arg; + + /* Consumed 'h' from the format string. */ + ++*fmt_ptr; + + for ( i = 0; i < nr_bytes; ++i ) + { + /* Each byte: 2 chars, 0-padded, base 16, no hex prefix. */ + str = number(str, end, hex_buffer[i], 16, 2, -1, ZEROPAD); + if ( str < end ) + *str = ' '; + ++str; + } + + return str; + } + case 's': /* Symbol name with offset and size (iff offset != 0) */ case 'S': /* Symbol name unconditionally with offset and size */ { -- 1.7.10.4