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seq_buf: Add printing formatted hex dumps

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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: Piotr Maziarz <piotrx.maziarz@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Piotr Maziarz 2019-11-07 13:45:37 +01:00 committed by Steven Rostedt (VMware)
parent c7411a1a12
commit 353cade314
2 changed files with 65 additions and 0 deletions
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3
include/linux/seq_buf.h
View File

@ -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

62
lib/seq_buf.c
View File

@ -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;
}