// 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;
		}
	}
}