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// SPDX-License-Identifier: GPL-2.0-only
/*
* lib/hexdump.c
*/
#include <stdio.h>
#include "linux_types.h"
#include "defs.h"
#define __get_unaligned_t(type, ptr) ({ \
const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \
__pptr->x; \
})
#define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr))
const char hex_asc[] = "0123456789abcdef";
#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
#define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
void print_hex_dump(const char *prefix_str, int prefix_type,
int rowsize, int groupsize,
const void *buf, size_t len, bool ascii);
/**
* hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
* @buf: data blob to dump
* @len: number of bytes in the @buf
* @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)
* @linebuf: where to put the converted data
* @linebuflen: total size of @linebuf, including space for terminating NUL
* @ascii: include ASCII after the hex output
*
* hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
* 16 or 32 bytes of input data converted to hex + ASCII output.
*
* Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
* to a hex + ASCII dump at the supplied memory location.
* The converted output is always NUL-terminated.
*
* E.g.:
* hex_dump_to_buffer(frame->data, frame->len, 16, 1,
* linebuf, sizeof(linebuf), true);
*
* example output buffer:
* 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
*
* Return:
* The amount of bytes placed in the buffer without terminating NUL. If the
* output was truncated, then the return value is the number of bytes
* (excluding the terminating NUL) which would have been written to the final
* string if enough space had been available.
*/
static int hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
int groupsize, char *linebuf, size_t linebuflen,
bool ascii)
{
const u8 *ptr = buf;
int ngroups;
u8 ch;
int j, lx = 0;
int ascii_column;
int ret;
if (rowsize != 16 && rowsize != 32)
rowsize = 16;
if (len > rowsize) /* limit to one line at a time */
len = rowsize;
if (!is_power_of_2(groupsize) || groupsize > 8)
groupsize = 1;
if ((len % groupsize) != 0) /* no mixed size output */
groupsize = 1;
ngroups = len / groupsize;
ascii_column = rowsize * 2 + rowsize / groupsize + 1;
if (!linebuflen)
goto overflow1;
if (!len)
goto nil;
if (groupsize == 8) {
const u64 *ptr8 = buf;
for (j = 0; j < ngroups; j++) {
ret = snprintf(linebuf + lx, linebuflen - lx,
"%s%16.16llx", j ? " " : "",
get_unaligned(ptr8 + j));
if (ret >= linebuflen - lx)
goto overflow1;
lx += ret;
}
} else if (groupsize == 4) {
const u32 *ptr4 = buf;
for (j = 0; j < ngroups; j++) {
ret = snprintf(linebuf + lx, linebuflen - lx,
"%s%8.8x", j ? " " : "",
get_unaligned(ptr4 + j));
if (ret >= linebuflen - lx)
goto overflow1;
lx += ret;
}
} else if (groupsize == 2) {
const u16 *ptr2 = buf;
for (j = 0; j < ngroups; j++) {
ret = snprintf(linebuf + lx, linebuflen - lx,
"%s%4.4x", j ? " " : "",
get_unaligned(ptr2 + j));
if (ret >= linebuflen - lx)
goto overflow1;
lx += ret;
}
} else {
for (j = 0; j < len; j++) {
if (linebuflen < lx + 2)
goto overflow2;
ch = ptr[j];
linebuf[lx++] = hex_asc_hi(ch);
if (linebuflen < lx + 2)
goto overflow2;
linebuf[lx++] = hex_asc_lo(ch);
if (linebuflen < lx + 2)
goto overflow2;
linebuf[lx++] = ' ';
}
if (j)
lx--;
}
if (!ascii)
goto nil;
while (lx < ascii_column) {
if (linebuflen < lx + 2)
goto overflow2;
linebuf[lx++] = ' ';
}
for (j = 0; j < len; j++) {
if (linebuflen < lx + 2)
goto overflow2;
ch = ptr[j];
linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
}
nil:
linebuf[lx] = '\0';
return lx;
overflow2:
linebuf[lx++] = '\0';
overflow1:
return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
}
/**
* print_hex_dump - print a text hex dump to syslog for a binary blob of data
* @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
*
* Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
* to the kernel log at the specified kernel log level, with an optional
* leading prefix.
*
* print_hex_dump() works on one "line" of output at a time, i.e.,
* 16 or 32 bytes of input data converted to hex + ASCII output.
* print_hex_dump() iterates over the entire input @buf, breaking it into
* "line size" chunks to format and print.
*
* E.g.:
* print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
* 16, 1, frame->data, frame->len, true);
*
* Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
* 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
* Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
* ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
*/
void print_hex_dump(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;
char linebuf[32 * 3 + 2 + 32 + 1];
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:
printf("%s%p: %s\n", prefix_str, ptr + i, linebuf);
break;
case DUMP_PREFIX_OFFSET:
printf("%s%.8x: %s\n", prefix_str, i, linebuf);
break;
default:
printf("%s%s\n", prefix_str, linebuf);
break;
}
}
}
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