Commit 353cade3 authored by Piotr Maziarz's avatar Piotr Maziarz Committed by Steven Rostedt (VMware)
Browse files

seq_buf: Add printing formatted hex dumps 

Provided function is an analogue of print_hex_dump().

Implementing this function in seq_buf allows using for multiple
purposes (e.g. for tracing) and therefore prevents from code duplication
in every layer that uses seq_buf.

print_hex_dump() is an essential part of logging data to dmesg. Adding
similar capability for other purposes is beneficial to all users.

Example usage:
seq_buf_hex_dump(seq, "", DUMP_PREFIX_OFFSET, 16, 4, buf,
		 ARRAY_SIZE(buf), true);
Example output:
00000000: 00000000 ffffff10 ffffff32 ffff3210  ........2....2..
00000010: ffff3210 83d00437 c0700000 00000000  .2..7.....p.....
00000020: 02010004 0000000f 0000000f 00004002  .............@..
00000030: 00000fff 00000000                    ........

Link: http://lkml.kernel.org/r/1573130738-29390-1-git-send-email-piotrx.maziarz@linux.intel.com



Signed-off-by: default avatarPiotr Maziarz <piotrx.maziarz@linux.intel.com>
Signed-off-by: default avatarCezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent c7411a1a

include/linux/seq_buf.h

+3 −0
Original line number Diff line number Diff line
@@ -125,6 +125,9 @@ extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len); 
extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,

			      unsigned int len);

extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);

extern int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str,

			    int prefix_type, int rowsize, int groupsize,

			    const void *buf, size_t len, bool ascii);



#ifdef CONFIG_BINARY_PRINTF

extern int

lib/seq_buf.c

+62 −0
Original line number Diff line number Diff line
@@ -328,3 +328,65 @@ int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt) 
	s->readpos += cnt;

	return cnt;

}



/**

 * seq_buf_hex_dump - print formatted hex dump into the sequence buffer

 * @s: seq_buf descriptor

 * @prefix_str: string to prefix each line with;

 *  caller supplies trailing spaces for alignment if desired

 * @prefix_type: controls whether prefix of an offset, address, or none

 *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)

 * @rowsize: number of bytes to print per line; must be 16 or 32

 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)

 * @buf: data blob to dump

 * @len: number of bytes in the @buf

 * @ascii: include ASCII after the hex output

 *

 * Function is an analogue of print_hex_dump() and thus has similar interface.

 *

 * linebuf size is maximal length for one line.

 * 32 * 3 - maximum bytes per line, each printed into 2 chars + 1 for

 *	separating space

 * 2 - spaces separating hex dump and ascii representation

 * 32 - ascii representation

 * 1 - terminating '\0'

 *

 * Returns zero on success, -1 on overflow

 */

int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str, int prefix_type,

		     int rowsize, int groupsize,

		     const void *buf, size_t len, bool ascii)

{

	const u8 *ptr = buf;

	int i, linelen, remaining = len;

	unsigned char linebuf[32 * 3 + 2 + 32 + 1];

	int ret;



	if (rowsize != 16 && rowsize != 32)

		rowsize = 16;



	for (i = 0; i < len; i += rowsize) {

		linelen = min(remaining, rowsize);

		remaining -= rowsize;



		hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,

				   linebuf, sizeof(linebuf), ascii);



		switch (prefix_type) {

		case DUMP_PREFIX_ADDRESS:

			ret = seq_buf_printf(s, "%s%p: %s\n",

			       prefix_str, ptr + i, linebuf);

			break;

		case DUMP_PREFIX_OFFSET:

			ret = seq_buf_printf(s, "%s%.8x: %s\n",

					     prefix_str, i, linebuf);

			break;

		default:

			ret = seq_buf_printf(s, "%s%s\n", prefix_str, linebuf);

			break;

		}

		if (ret)

			return ret;

	}

	return 0;

}

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