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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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ea053e164c
I'm exposing some information about NFS clients in pseudofiles. I expect to eventually have simple tools to help read those pseudofiles. But it's also helpful if the raw files are human-readable to the extent possible. It aids debugging and makes them usable on systems that don't have the latest nfs-utils. A minor challenge there is opaque client-generated protocol objects like state owners and client identifiers. Some clients generate those to include handy information in plain ascii. But they may also include arbitrary byte sequences. I think the simplest approach is to limit to isprint(c) && isascii(c) and escape everything else. That means you can just cat the file and get something that looks OK. Also, I'm trying to keep these files legal YAML, which requires them to UTF-8, and this is a simple way to guarantee that. Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
649 lines
14 KiB
C
649 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Helpers for formatting and printing strings
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*
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* Copyright 31 August 2008 James Bottomley
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* Copyright (C) 2013, Intel Corporation
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*/
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#include <linux/bug.h>
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#include <linux/kernel.h>
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#include <linux/math64.h>
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#include <linux/export.h>
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#include <linux/ctype.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/limits.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/string_helpers.h>
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/**
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* string_get_size - get the size in the specified units
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* @size: The size to be converted in blocks
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* @blk_size: Size of the block (use 1 for size in bytes)
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* @units: units to use (powers of 1000 or 1024)
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* @buf: buffer to format to
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* @len: length of buffer
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*
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* This function returns a string formatted to 3 significant figures
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* giving the size in the required units. @buf should have room for
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* at least 9 bytes and will always be zero terminated.
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*
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*/
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void string_get_size(u64 size, u64 blk_size, const enum string_size_units units,
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char *buf, int len)
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{
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static const char *const units_10[] = {
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"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"
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};
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static const char *const units_2[] = {
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"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"
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};
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static const char *const *const units_str[] = {
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[STRING_UNITS_10] = units_10,
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[STRING_UNITS_2] = units_2,
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};
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static const unsigned int divisor[] = {
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[STRING_UNITS_10] = 1000,
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[STRING_UNITS_2] = 1024,
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};
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static const unsigned int rounding[] = { 500, 50, 5 };
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int i = 0, j;
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u32 remainder = 0, sf_cap;
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char tmp[8];
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const char *unit;
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tmp[0] = '\0';
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if (blk_size == 0)
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size = 0;
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if (size == 0)
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goto out;
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/* This is Napier's algorithm. Reduce the original block size to
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*
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* coefficient * divisor[units]^i
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*
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* we do the reduction so both coefficients are just under 32 bits so
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* that multiplying them together won't overflow 64 bits and we keep
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* as much precision as possible in the numbers.
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*
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* Note: it's safe to throw away the remainders here because all the
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* precision is in the coefficients.
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*/
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while (blk_size >> 32) {
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do_div(blk_size, divisor[units]);
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i++;
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}
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while (size >> 32) {
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do_div(size, divisor[units]);
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i++;
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}
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/* now perform the actual multiplication keeping i as the sum of the
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* two logarithms */
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size *= blk_size;
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/* and logarithmically reduce it until it's just under the divisor */
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while (size >= divisor[units]) {
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remainder = do_div(size, divisor[units]);
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i++;
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}
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/* work out in j how many digits of precision we need from the
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* remainder */
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sf_cap = size;
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for (j = 0; sf_cap*10 < 1000; j++)
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sf_cap *= 10;
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if (units == STRING_UNITS_2) {
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/* express the remainder as a decimal. It's currently the
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* numerator of a fraction whose denominator is
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* divisor[units], which is 1 << 10 for STRING_UNITS_2 */
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remainder *= 1000;
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remainder >>= 10;
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}
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/* add a 5 to the digit below what will be printed to ensure
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* an arithmetical round up and carry it through to size */
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remainder += rounding[j];
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if (remainder >= 1000) {
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remainder -= 1000;
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size += 1;
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}
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if (j) {
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snprintf(tmp, sizeof(tmp), ".%03u", remainder);
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tmp[j+1] = '\0';
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}
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out:
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if (i >= ARRAY_SIZE(units_2))
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unit = "UNK";
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else
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unit = units_str[units][i];
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snprintf(buf, len, "%u%s %s", (u32)size,
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tmp, unit);
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}
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EXPORT_SYMBOL(string_get_size);
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static bool unescape_space(char **src, char **dst)
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{
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char *p = *dst, *q = *src;
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switch (*q) {
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case 'n':
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*p = '\n';
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break;
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case 'r':
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*p = '\r';
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break;
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case 't':
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*p = '\t';
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break;
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case 'v':
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*p = '\v';
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break;
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case 'f':
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*p = '\f';
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break;
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default:
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return false;
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}
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*dst += 1;
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*src += 1;
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return true;
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}
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static bool unescape_octal(char **src, char **dst)
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{
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char *p = *dst, *q = *src;
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u8 num;
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if (isodigit(*q) == 0)
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return false;
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num = (*q++) & 7;
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while (num < 32 && isodigit(*q) && (q - *src < 3)) {
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num <<= 3;
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num += (*q++) & 7;
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}
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*p = num;
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*dst += 1;
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*src = q;
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return true;
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}
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static bool unescape_hex(char **src, char **dst)
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{
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char *p = *dst, *q = *src;
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int digit;
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u8 num;
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if (*q++ != 'x')
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return false;
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num = digit = hex_to_bin(*q++);
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if (digit < 0)
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return false;
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digit = hex_to_bin(*q);
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if (digit >= 0) {
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q++;
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num = (num << 4) | digit;
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}
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*p = num;
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*dst += 1;
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*src = q;
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return true;
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}
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static bool unescape_special(char **src, char **dst)
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{
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char *p = *dst, *q = *src;
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switch (*q) {
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case '\"':
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*p = '\"';
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break;
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case '\\':
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*p = '\\';
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break;
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case 'a':
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*p = '\a';
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break;
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case 'e':
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*p = '\e';
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break;
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default:
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return false;
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}
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*dst += 1;
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*src += 1;
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return true;
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}
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/**
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* string_unescape - unquote characters in the given string
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* @src: source buffer (escaped)
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* @dst: destination buffer (unescaped)
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* @size: size of the destination buffer (0 to unlimit)
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* @flags: combination of the flags (bitwise OR):
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* %UNESCAPE_SPACE:
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* '\f' - form feed
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* '\n' - new line
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* '\r' - carriage return
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* '\t' - horizontal tab
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* '\v' - vertical tab
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* %UNESCAPE_OCTAL:
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* '\NNN' - byte with octal value NNN (1 to 3 digits)
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* %UNESCAPE_HEX:
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* '\xHH' - byte with hexadecimal value HH (1 to 2 digits)
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* %UNESCAPE_SPECIAL:
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* '\"' - double quote
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* '\\' - backslash
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* '\a' - alert (BEL)
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* '\e' - escape
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* %UNESCAPE_ANY:
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* all previous together
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*
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* Description:
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* The function unquotes characters in the given string.
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*
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* Because the size of the output will be the same as or less than the size of
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* the input, the transformation may be performed in place.
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*
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* Caller must provide valid source and destination pointers. Be aware that
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* destination buffer will always be NULL-terminated. Source string must be
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* NULL-terminated as well.
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*
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* Return:
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* The amount of the characters processed to the destination buffer excluding
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* trailing '\0' is returned.
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*/
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int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
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{
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char *out = dst;
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while (*src && --size) {
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if (src[0] == '\\' && src[1] != '\0' && size > 1) {
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src++;
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size--;
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if (flags & UNESCAPE_SPACE &&
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unescape_space(&src, &out))
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continue;
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if (flags & UNESCAPE_OCTAL &&
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unescape_octal(&src, &out))
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continue;
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if (flags & UNESCAPE_HEX &&
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unescape_hex(&src, &out))
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continue;
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if (flags & UNESCAPE_SPECIAL &&
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unescape_special(&src, &out))
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continue;
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*out++ = '\\';
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}
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*out++ = *src++;
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}
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*out = '\0';
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return out - dst;
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}
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EXPORT_SYMBOL(string_unescape);
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static bool escape_passthrough(unsigned char c, char **dst, char *end)
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{
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char *out = *dst;
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if (out < end)
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*out = c;
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*dst = out + 1;
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return true;
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}
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static bool escape_space(unsigned char c, char **dst, char *end)
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{
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char *out = *dst;
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unsigned char to;
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switch (c) {
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case '\n':
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to = 'n';
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break;
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case '\r':
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to = 'r';
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break;
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case '\t':
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to = 't';
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break;
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case '\v':
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to = 'v';
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break;
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case '\f':
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to = 'f';
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break;
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default:
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return false;
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}
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if (out < end)
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*out = '\\';
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++out;
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if (out < end)
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*out = to;
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++out;
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*dst = out;
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return true;
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}
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static bool escape_special(unsigned char c, char **dst, char *end)
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{
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char *out = *dst;
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unsigned char to;
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switch (c) {
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case '\\':
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to = '\\';
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break;
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case '\a':
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to = 'a';
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break;
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case '\e':
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to = 'e';
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break;
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default:
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return false;
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}
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if (out < end)
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*out = '\\';
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++out;
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if (out < end)
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*out = to;
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++out;
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*dst = out;
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return true;
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}
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static bool escape_null(unsigned char c, char **dst, char *end)
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{
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char *out = *dst;
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if (c)
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return false;
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if (out < end)
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*out = '\\';
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++out;
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if (out < end)
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*out = '0';
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++out;
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*dst = out;
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return true;
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}
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static bool escape_octal(unsigned char c, char **dst, char *end)
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{
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char *out = *dst;
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if (out < end)
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*out = '\\';
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++out;
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if (out < end)
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*out = ((c >> 6) & 0x07) + '0';
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++out;
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if (out < end)
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*out = ((c >> 3) & 0x07) + '0';
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++out;
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if (out < end)
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*out = ((c >> 0) & 0x07) + '0';
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++out;
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*dst = out;
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return true;
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}
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static bool escape_hex(unsigned char c, char **dst, char *end)
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{
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char *out = *dst;
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if (out < end)
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*out = '\\';
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++out;
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if (out < end)
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*out = 'x';
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++out;
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if (out < end)
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*out = hex_asc_hi(c);
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++out;
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if (out < end)
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*out = hex_asc_lo(c);
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++out;
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*dst = out;
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return true;
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}
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/**
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* string_escape_mem - quote characters in the given memory buffer
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* @src: source buffer (unescaped)
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* @isz: source buffer size
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* @dst: destination buffer (escaped)
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* @osz: destination buffer size
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* @flags: combination of the flags (bitwise OR):
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* %ESCAPE_SPACE: (special white space, not space itself)
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* '\f' - form feed
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* '\n' - new line
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* '\r' - carriage return
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* '\t' - horizontal tab
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* '\v' - vertical tab
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* %ESCAPE_SPECIAL:
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* '\\' - backslash
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* '\a' - alert (BEL)
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* '\e' - escape
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* %ESCAPE_NULL:
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* '\0' - null
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* %ESCAPE_OCTAL:
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* '\NNN' - byte with octal value NNN (3 digits)
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* %ESCAPE_ANY:
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* all previous together
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* %ESCAPE_NP:
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* escape only non-printable characters (checked by isprint)
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* %ESCAPE_ANY_NP:
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* all previous together
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* %ESCAPE_HEX:
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* '\xHH' - byte with hexadecimal value HH (2 digits)
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* @only: NULL-terminated string containing characters used to limit
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* the selected escape class. If characters are included in @only
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* that would not normally be escaped by the classes selected
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* in @flags, they will be copied to @dst unescaped.
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*
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* Description:
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* The process of escaping byte buffer includes several parts. They are applied
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* in the following sequence.
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* 1. The character is matched to the printable class, if asked, and in
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* case of match it passes through to the output.
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* 2. The character is not matched to the one from @only string and thus
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* must go as-is to the output.
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* 3. The character is checked if it falls into the class given by @flags.
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* %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
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* character. Note that they actually can't go together, otherwise
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* %ESCAPE_HEX will be ignored.
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*
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* Caller must provide valid source and destination pointers. Be aware that
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* destination buffer will not be NULL-terminated, thus caller have to append
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* it if needs.
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*
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* Return:
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* The total size of the escaped output that would be generated for
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* the given input and flags. To check whether the output was
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* truncated, compare the return value to osz. There is room left in
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* dst for a '\0' terminator if and only if ret < osz.
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*/
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int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
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unsigned int flags, const char *only)
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{
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char *p = dst;
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char *end = p + osz;
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bool is_dict = only && *only;
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while (isz--) {
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unsigned char c = *src++;
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/*
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* Apply rules in the following sequence:
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* - the character is printable, when @flags has
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* %ESCAPE_NP bit set
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* - the @only string is supplied and does not contain a
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* character under question
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* - the character doesn't fall into a class of symbols
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* defined by given @flags
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* In these cases we just pass through a character to the
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* output buffer.
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*/
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if ((flags & ESCAPE_NP && isprint(c)) ||
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(is_dict && !strchr(only, c))) {
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/* do nothing */
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} else {
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if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
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continue;
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if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
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continue;
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if (flags & ESCAPE_NULL && escape_null(c, &p, end))
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continue;
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/* ESCAPE_OCTAL and ESCAPE_HEX always go last */
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if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
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continue;
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if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
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continue;
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}
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escape_passthrough(c, &p, end);
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}
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return p - dst;
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}
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EXPORT_SYMBOL(string_escape_mem);
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int string_escape_mem_ascii(const char *src, size_t isz, char *dst,
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size_t osz)
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{
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char *p = dst;
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char *end = p + osz;
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while (isz--) {
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unsigned char c = *src++;
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if (!isprint(c) || !isascii(c) || c == '"' || c == '\\')
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escape_hex(c, &p, end);
|
|
else
|
|
escape_passthrough(c, &p, end);
|
|
}
|
|
|
|
return p - dst;
|
|
}
|
|
EXPORT_SYMBOL(string_escape_mem_ascii);
|
|
|
|
/*
|
|
* Return an allocated string that has been escaped of special characters
|
|
* and double quotes, making it safe to log in quotes.
|
|
*/
|
|
char *kstrdup_quotable(const char *src, gfp_t gfp)
|
|
{
|
|
size_t slen, dlen;
|
|
char *dst;
|
|
const int flags = ESCAPE_HEX;
|
|
const char esc[] = "\f\n\r\t\v\a\e\\\"";
|
|
|
|
if (!src)
|
|
return NULL;
|
|
slen = strlen(src);
|
|
|
|
dlen = string_escape_mem(src, slen, NULL, 0, flags, esc);
|
|
dst = kmalloc(dlen + 1, gfp);
|
|
if (!dst)
|
|
return NULL;
|
|
|
|
WARN_ON(string_escape_mem(src, slen, dst, dlen, flags, esc) != dlen);
|
|
dst[dlen] = '\0';
|
|
|
|
return dst;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kstrdup_quotable);
|
|
|
|
/*
|
|
* Returns allocated NULL-terminated string containing process
|
|
* command line, with inter-argument NULLs replaced with spaces,
|
|
* and other special characters escaped.
|
|
*/
|
|
char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp)
|
|
{
|
|
char *buffer, *quoted;
|
|
int i, res;
|
|
|
|
buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
|
|
if (!buffer)
|
|
return NULL;
|
|
|
|
res = get_cmdline(task, buffer, PAGE_SIZE - 1);
|
|
buffer[res] = '\0';
|
|
|
|
/* Collapse trailing NULLs, leave res pointing to last non-NULL. */
|
|
while (--res >= 0 && buffer[res] == '\0')
|
|
;
|
|
|
|
/* Replace inter-argument NULLs. */
|
|
for (i = 0; i <= res; i++)
|
|
if (buffer[i] == '\0')
|
|
buffer[i] = ' ';
|
|
|
|
/* Make sure result is printable. */
|
|
quoted = kstrdup_quotable(buffer, gfp);
|
|
kfree(buffer);
|
|
return quoted;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kstrdup_quotable_cmdline);
|
|
|
|
/*
|
|
* Returns allocated NULL-terminated string containing pathname,
|
|
* with special characters escaped, able to be safely logged. If
|
|
* there is an error, the leading character will be "<".
|
|
*/
|
|
char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
|
|
{
|
|
char *temp, *pathname;
|
|
|
|
if (!file)
|
|
return kstrdup("<unknown>", gfp);
|
|
|
|
/* We add 11 spaces for ' (deleted)' to be appended */
|
|
temp = kmalloc(PATH_MAX + 11, GFP_KERNEL);
|
|
if (!temp)
|
|
return kstrdup("<no_memory>", gfp);
|
|
|
|
pathname = file_path(file, temp, PATH_MAX + 11);
|
|
if (IS_ERR(pathname))
|
|
pathname = kstrdup("<too_long>", gfp);
|
|
else
|
|
pathname = kstrdup_quotable(pathname, gfp);
|
|
|
|
kfree(temp);
|
|
return pathname;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kstrdup_quotable_file);
|