296 lines
8.5 KiB
C
296 lines
8.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* lib/hexdump.c
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*/
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#include <linux/types.h>
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#include <linux/ctype.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/minmax.h>
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#include <linux/export.h>
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#include <asm/unaligned.h>
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const char hex_asc[] = "0123456789abcdef";
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EXPORT_SYMBOL(hex_asc);
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const char hex_asc_upper[] = "0123456789ABCDEF";
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EXPORT_SYMBOL(hex_asc_upper);
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/**
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* hex_to_bin - convert a hex digit to its real value
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* @ch: ascii character represents hex digit
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*
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* hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
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* input.
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*
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* This function is used to load cryptographic keys, so it is coded in such a
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* way that there are no conditions or memory accesses that depend on data.
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*
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* Explanation of the logic:
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* (ch - '9' - 1) is negative if ch <= '9'
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* ('0' - 1 - ch) is negative if ch >= '0'
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* we "and" these two values, so the result is negative if ch is in the range
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* '0' ... '9'
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* we are only interested in the sign, so we do a shift ">> 8"; note that right
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* shift of a negative value is implementation-defined, so we cast the
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* value to (unsigned) before the shift --- we have 0xffffff if ch is in
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* the range '0' ... '9', 0 otherwise
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* we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is
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* in the range '0' ... '9', 0 otherwise
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* we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0'
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* ... '9', -1 otherwise
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* the next line is similar to the previous one, but we need to decode both
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* uppercase and lowercase letters, so we use (ch & 0xdf), which converts
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* lowercase to uppercase
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*/
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int hex_to_bin(unsigned char ch)
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{
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unsigned char cu = ch & 0xdf;
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return -1 +
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((ch - '0' + 1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +
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((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);
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}
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EXPORT_SYMBOL(hex_to_bin);
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/**
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* hex2bin - convert an ascii hexadecimal string to its binary representation
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* @dst: binary result
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* @src: ascii hexadecimal string
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* @count: result length
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*
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* Return 0 on success, -EINVAL in case of bad input.
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*/
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int hex2bin(u8 *dst, const char *src, size_t count)
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{
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while (count--) {
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int hi, lo;
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hi = hex_to_bin(*src++);
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if (unlikely(hi < 0))
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return -EINVAL;
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lo = hex_to_bin(*src++);
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if (unlikely(lo < 0))
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return -EINVAL;
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*dst++ = (hi << 4) | lo;
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}
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return 0;
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}
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EXPORT_SYMBOL(hex2bin);
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/**
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* bin2hex - convert binary data to an ascii hexadecimal string
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* @dst: ascii hexadecimal result
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* @src: binary data
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* @count: binary data length
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*/
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char *bin2hex(char *dst, const void *src, size_t count)
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{
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const unsigned char *_src = src;
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while (count--)
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dst = hex_byte_pack(dst, *_src++);
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return dst;
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}
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EXPORT_SYMBOL(bin2hex);
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/**
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* hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
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* @buf: data blob to dump
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* @len: number of bytes in the @buf
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* @rowsize: number of bytes to print per line; must be 16 or 32
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* @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
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* @linebuf: where to put the converted data
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* @linebuflen: total size of @linebuf, including space for terminating NUL
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* @ascii: include ASCII after the hex output
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*
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* hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
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* 16 or 32 bytes of input data converted to hex + ASCII output.
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*
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* Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
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* to a hex + ASCII dump at the supplied memory location.
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* The converted output is always NUL-terminated.
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*
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* E.g.:
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* hex_dump_to_buffer(frame->data, frame->len, 16, 1,
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* linebuf, sizeof(linebuf), true);
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*
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* example output buffer:
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* 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
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*
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* Return:
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* The amount of bytes placed in the buffer without terminating NUL. If the
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* output was truncated, then the return value is the number of bytes
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* (excluding the terminating NUL) which would have been written to the final
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* string if enough space had been available.
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*/
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int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
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char *linebuf, size_t linebuflen, bool ascii)
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{
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const u8 *ptr = buf;
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int ngroups;
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u8 ch;
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int j, lx = 0;
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int ascii_column;
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int ret;
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if (rowsize != 16 && rowsize != 32)
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rowsize = 16;
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if (len > rowsize) /* limit to one line at a time */
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len = rowsize;
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if (!is_power_of_2(groupsize) || groupsize > 8)
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groupsize = 1;
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if ((len % groupsize) != 0) /* no mixed size output */
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groupsize = 1;
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ngroups = len / groupsize;
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ascii_column = rowsize * 2 + rowsize / groupsize + 1;
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if (!linebuflen)
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goto overflow1;
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if (!len)
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goto nil;
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if (groupsize == 8) {
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const u64 *ptr8 = buf;
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for (j = 0; j < ngroups; j++) {
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ret = snprintf(linebuf + lx, linebuflen - lx,
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"%s%16.16llx", j ? " " : "",
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get_unaligned(ptr8 + j));
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if (ret >= linebuflen - lx)
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goto overflow1;
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lx += ret;
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}
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} else if (groupsize == 4) {
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const u32 *ptr4 = buf;
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for (j = 0; j < ngroups; j++) {
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ret = snprintf(linebuf + lx, linebuflen - lx,
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"%s%8.8x", j ? " " : "",
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get_unaligned(ptr4 + j));
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if (ret >= linebuflen - lx)
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goto overflow1;
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lx += ret;
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}
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} else if (groupsize == 2) {
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const u16 *ptr2 = buf;
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for (j = 0; j < ngroups; j++) {
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ret = snprintf(linebuf + lx, linebuflen - lx,
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"%s%4.4x", j ? " " : "",
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get_unaligned(ptr2 + j));
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if (ret >= linebuflen - lx)
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goto overflow1;
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lx += ret;
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}
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} else {
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for (j = 0; j < len; j++) {
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if (linebuflen < lx + 2)
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goto overflow2;
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ch = ptr[j];
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linebuf[lx++] = hex_asc_hi(ch);
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if (linebuflen < lx + 2)
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goto overflow2;
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linebuf[lx++] = hex_asc_lo(ch);
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if (linebuflen < lx + 2)
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goto overflow2;
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linebuf[lx++] = ' ';
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}
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if (j)
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lx--;
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}
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if (!ascii)
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goto nil;
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while (lx < ascii_column) {
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if (linebuflen < lx + 2)
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goto overflow2;
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linebuf[lx++] = ' ';
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}
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for (j = 0; j < len; j++) {
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if (linebuflen < lx + 2)
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goto overflow2;
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ch = ptr[j];
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linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
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}
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nil:
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linebuf[lx] = '\0';
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return lx;
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overflow2:
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linebuf[lx++] = '\0';
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overflow1:
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return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
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}
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EXPORT_SYMBOL(hex_dump_to_buffer);
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#ifdef CONFIG_PRINTK
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/**
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* print_hex_dump - print a text hex dump to syslog for a binary blob of data
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* @level: kernel log level (e.g. KERN_DEBUG)
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* @prefix_str: string to prefix each line with;
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* caller supplies trailing spaces for alignment if desired
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* @prefix_type: controls whether prefix of an offset, address, or none
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* is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
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* @rowsize: number of bytes to print per line; must be 16 or 32
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* @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
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* @buf: data blob to dump
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* @len: number of bytes in the @buf
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* @ascii: include ASCII after the hex output
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*
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* Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
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* to the kernel log at the specified kernel log level, with an optional
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* leading prefix.
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*
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* print_hex_dump() works on one "line" of output at a time, i.e.,
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* 16 or 32 bytes of input data converted to hex + ASCII output.
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* print_hex_dump() iterates over the entire input @buf, breaking it into
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* "line size" chunks to format and print.
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*
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* E.g.:
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* print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
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* 16, 1, frame->data, frame->len, true);
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*
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* Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
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* 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
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* Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
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* ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
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*/
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void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
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int rowsize, int groupsize,
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const void *buf, size_t len, bool ascii)
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{
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const u8 *ptr = buf;
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int i, linelen, remaining = len;
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unsigned char linebuf[32 * 3 + 2 + 32 + 1];
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if (rowsize != 16 && rowsize != 32)
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rowsize = 16;
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for (i = 0; i < len; i += rowsize) {
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linelen = min(remaining, rowsize);
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remaining -= rowsize;
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hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
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linebuf, sizeof(linebuf), ascii);
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switch (prefix_type) {
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case DUMP_PREFIX_ADDRESS:
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printk("%s%s%p: %s\n",
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level, prefix_str, ptr + i, linebuf);
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break;
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case DUMP_PREFIX_OFFSET:
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printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
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break;
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default:
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printk("%s%s%s\n", level, prefix_str, linebuf);
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break;
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}
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}
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}
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EXPORT_SYMBOL(print_hex_dump);
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#endif /* defined(CONFIG_PRINTK) */
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