From 4f5dd3943bef8a04be7e3b838b822bb9a7ad6cb3 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 23 Oct 2015 18:52:53 +0200 Subject: util: split out escaping code into escape.[ch] This really deserves its own file, given how much code this is now. --- src/basic/escape.c | 480 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 480 insertions(+) create mode 100644 src/basic/escape.c (limited to 'src/basic/escape.c') diff --git a/src/basic/escape.c b/src/basic/escape.c new file mode 100644 index 0000000000..cf05ce10ef --- /dev/null +++ b/src/basic/escape.c @@ -0,0 +1,480 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2010 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see . +***/ + +#include "utf8.h" +#include "util.h" + +#include "escape.h" + +size_t cescape_char(char c, char *buf) { + char * buf_old = buf; + + switch (c) { + + case '\a': + *(buf++) = '\\'; + *(buf++) = 'a'; + break; + case '\b': + *(buf++) = '\\'; + *(buf++) = 'b'; + break; + case '\f': + *(buf++) = '\\'; + *(buf++) = 'f'; + break; + case '\n': + *(buf++) = '\\'; + *(buf++) = 'n'; + break; + case '\r': + *(buf++) = '\\'; + *(buf++) = 'r'; + break; + case '\t': + *(buf++) = '\\'; + *(buf++) = 't'; + break; + case '\v': + *(buf++) = '\\'; + *(buf++) = 'v'; + break; + case '\\': + *(buf++) = '\\'; + *(buf++) = '\\'; + break; + case '"': + *(buf++) = '\\'; + *(buf++) = '"'; + break; + case '\'': + *(buf++) = '\\'; + *(buf++) = '\''; + break; + + default: + /* For special chars we prefer octal over + * hexadecimal encoding, simply because glib's + * g_strescape() does the same */ + if ((c < ' ') || (c >= 127)) { + *(buf++) = '\\'; + *(buf++) = octchar((unsigned char) c >> 6); + *(buf++) = octchar((unsigned char) c >> 3); + *(buf++) = octchar((unsigned char) c); + } else + *(buf++) = c; + break; + } + + return buf - buf_old; +} + +char *cescape(const char *s) { + char *r, *t; + const char *f; + + assert(s); + + /* Does C style string escaping. May be reversed with + * cunescape(). */ + + r = new(char, strlen(s)*4 + 1); + if (!r) + return NULL; + + for (f = s, t = r; *f; f++) + t += cescape_char(*f, t); + + *t = 0; + + return r; +} + +int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode) { + int r = 1; + + assert(p); + assert(*p); + assert(ret); + + /* Unescapes C style. Returns the unescaped character in ret, + * unless we encountered a \u sequence in which case the full + * unicode character is returned in ret_unicode, instead. */ + + if (length != (size_t) -1 && length < 1) + return -EINVAL; + + switch (p[0]) { + + case 'a': + *ret = '\a'; + break; + case 'b': + *ret = '\b'; + break; + case 'f': + *ret = '\f'; + break; + case 'n': + *ret = '\n'; + break; + case 'r': + *ret = '\r'; + break; + case 't': + *ret = '\t'; + break; + case 'v': + *ret = '\v'; + break; + case '\\': + *ret = '\\'; + break; + case '"': + *ret = '"'; + break; + case '\'': + *ret = '\''; + break; + + case 's': + /* This is an extension of the XDG syntax files */ + *ret = ' '; + break; + + case 'x': { + /* hexadecimal encoding */ + int a, b; + + if (length != (size_t) -1 && length < 3) + return -EINVAL; + + a = unhexchar(p[1]); + if (a < 0) + return -EINVAL; + + b = unhexchar(p[2]); + if (b < 0) + return -EINVAL; + + /* Don't allow NUL bytes */ + if (a == 0 && b == 0) + return -EINVAL; + + *ret = (char) ((a << 4U) | b); + r = 3; + break; + } + + case 'u': { + /* C++11 style 16bit unicode */ + + int a[4]; + unsigned i; + uint32_t c; + + if (length != (size_t) -1 && length < 5) + return -EINVAL; + + for (i = 0; i < 4; i++) { + a[i] = unhexchar(p[1 + i]); + if (a[i] < 0) + return a[i]; + } + + c = ((uint32_t) a[0] << 12U) | ((uint32_t) a[1] << 8U) | ((uint32_t) a[2] << 4U) | (uint32_t) a[3]; + + /* Don't allow 0 chars */ + if (c == 0) + return -EINVAL; + + if (c < 128) + *ret = c; + else { + if (!ret_unicode) + return -EINVAL; + + *ret = 0; + *ret_unicode = c; + } + + r = 5; + break; + } + + case 'U': { + /* C++11 style 32bit unicode */ + + int a[8]; + unsigned i; + uint32_t c; + + if (length != (size_t) -1 && length < 9) + return -EINVAL; + + for (i = 0; i < 8; i++) { + a[i] = unhexchar(p[1 + i]); + if (a[i] < 0) + return a[i]; + } + + c = ((uint32_t) a[0] << 28U) | ((uint32_t) a[1] << 24U) | ((uint32_t) a[2] << 20U) | ((uint32_t) a[3] << 16U) | + ((uint32_t) a[4] << 12U) | ((uint32_t) a[5] << 8U) | ((uint32_t) a[6] << 4U) | (uint32_t) a[7]; + + /* Don't allow 0 chars */ + if (c == 0) + return -EINVAL; + + /* Don't allow invalid code points */ + if (!unichar_is_valid(c)) + return -EINVAL; + + if (c < 128) + *ret = c; + else { + if (!ret_unicode) + return -EINVAL; + + *ret = 0; + *ret_unicode = c; + } + + r = 9; + break; + } + + case '0': + case '1': + case '2': + case '3': + case '4': + case '5': + case '6': + case '7': { + /* octal encoding */ + int a, b, c; + uint32_t m; + + if (length != (size_t) -1 && length < 3) + return -EINVAL; + + a = unoctchar(p[0]); + if (a < 0) + return -EINVAL; + + b = unoctchar(p[1]); + if (b < 0) + return -EINVAL; + + c = unoctchar(p[2]); + if (c < 0) + return -EINVAL; + + /* don't allow NUL bytes */ + if (a == 0 && b == 0 && c == 0) + return -EINVAL; + + /* Don't allow bytes above 255 */ + m = ((uint32_t) a << 6U) | ((uint32_t) b << 3U) | (uint32_t) c; + if (m > 255) + return -EINVAL; + + *ret = m; + r = 3; + break; + } + + default: + return -EINVAL; + } + + return r; +} + +int cunescape_length_with_prefix(const char *s, size_t length, const char *prefix, UnescapeFlags flags, char **ret) { + char *r, *t; + const char *f; + size_t pl; + + assert(s); + assert(ret); + + /* Undoes C style string escaping, and optionally prefixes it. */ + + pl = prefix ? strlen(prefix) : 0; + + r = new(char, pl+length+1); + if (!r) + return -ENOMEM; + + if (prefix) + memcpy(r, prefix, pl); + + for (f = s, t = r + pl; f < s + length; f++) { + size_t remaining; + uint32_t u; + char c; + int k; + + remaining = s + length - f; + assert(remaining > 0); + + if (*f != '\\') { + /* A literal literal, copy verbatim */ + *(t++) = *f; + continue; + } + + if (remaining == 1) { + if (flags & UNESCAPE_RELAX) { + /* A trailing backslash, copy verbatim */ + *(t++) = *f; + continue; + } + + free(r); + return -EINVAL; + } + + k = cunescape_one(f + 1, remaining - 1, &c, &u); + if (k < 0) { + if (flags & UNESCAPE_RELAX) { + /* Invalid escape code, let's take it literal then */ + *(t++) = '\\'; + continue; + } + + free(r); + return k; + } + + if (c != 0) + /* Non-Unicode? Let's encode this directly */ + *(t++) = c; + else + /* Unicode? Then let's encode this in UTF-8 */ + t += utf8_encode_unichar(t, u); + + f += k; + } + + *t = 0; + + *ret = r; + return t - r; +} + +int cunescape_length(const char *s, size_t length, UnescapeFlags flags, char **ret) { + return cunescape_length_with_prefix(s, length, NULL, flags, ret); +} + +int cunescape(const char *s, UnescapeFlags flags, char **ret) { + return cunescape_length(s, strlen(s), flags, ret); +} + +char *xescape(const char *s, const char *bad) { + char *r, *t; + const char *f; + + /* Escapes all chars in bad, in addition to \ and all special + * chars, in \xFF style escaping. May be reversed with + * cunescape(). */ + + r = new(char, strlen(s) * 4 + 1); + if (!r) + return NULL; + + for (f = s, t = r; *f; f++) { + + if ((*f < ' ') || (*f >= 127) || + (*f == '\\') || strchr(bad, *f)) { + *(t++) = '\\'; + *(t++) = 'x'; + *(t++) = hexchar(*f >> 4); + *(t++) = hexchar(*f); + } else + *(t++) = *f; + } + + *t = 0; + + return r; +} + +static char *strcpy_backslash_escaped(char *t, const char *s, const char *bad) { + assert(bad); + + for (; *s; s++) { + if (*s == '\\' || strchr(bad, *s)) + *(t++) = '\\'; + + *(t++) = *s; + } + + return t; +} + +char *shell_escape(const char *s, const char *bad) { + char *r, *t; + + r = new(char, strlen(s)*2+1); + if (!r) + return NULL; + + t = strcpy_backslash_escaped(r, s, bad); + *t = 0; + + return r; +} + +char *shell_maybe_quote(const char *s) { + const char *p; + char *r, *t; + + assert(s); + + /* Encloses a string in double quotes if necessary to make it + * OK as shell string. */ + + for (p = s; *p; p++) + if (*p <= ' ' || + *p >= 127 || + strchr(SHELL_NEED_QUOTES, *p)) + break; + + if (!*p) + return strdup(s); + + r = new(char, 1+strlen(s)*2+1+1); + if (!r) + return NULL; + + t = r; + *(t++) = '"'; + t = mempcpy(t, s, p - s); + + t = strcpy_backslash_escaped(t, p, SHELL_NEED_ESCAPE); + + *(t++)= '"'; + *t = 0; + + return r; +} -- cgit v1.2.3-54-g00ecf