| /* $OpenBSD: utf8.c,v 1.5 2017/02/19 00:10:57 djm Exp $ */ |
| /* |
| * Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org> |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| /* |
| * Utility functions for multibyte-character handling, |
| * in particular to sanitize untrusted strings for terminal output. |
| */ |
| |
| #include "includes.h" |
| |
| #include <sys/types.h> |
| #ifdef HAVE_LANGINFO_H |
| # include <langinfo.h> |
| #endif |
| #include <limits.h> |
| #include <locale.h> |
| #include <stdarg.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS) |
| # include <vis.h> |
| #endif |
| #ifdef HAVE_WCHAR_H |
| # include <wchar.h> |
| #endif |
| |
| #include "utf8.h" |
| |
| static int dangerous_locale(void); |
| static int grow_dst(char **, size_t *, size_t, char **, size_t); |
| static int vasnmprintf(char **, size_t, int *, const char *, va_list); |
| |
| |
| /* |
| * For US-ASCII and UTF-8 encodings, we can safely recover from |
| * encoding errors and from non-printable characters. For any |
| * other encodings, err to the side of caution and abort parsing: |
| * For state-dependent encodings, recovery is impossible. |
| * For arbitrary encodings, replacement of non-printable |
| * characters would be non-trivial and too fragile. |
| */ |
| |
| static int |
| dangerous_locale(void) { |
| char *loc; |
| |
| loc = nl_langinfo(CODESET); |
| return strcmp(loc, "US-ASCII") != 0 && strcmp(loc, "UTF-8") != 0 && |
| strcmp(loc, "ANSI_X3.4-1968") != 0; |
| } |
| |
| static int |
| grow_dst(char **dst, size_t *sz, size_t maxsz, char **dp, size_t need) |
| { |
| char *tp; |
| size_t tsz; |
| |
| if (*dp + need < *dst + *sz) |
| return 0; |
| tsz = *sz + 128; |
| if (tsz > maxsz) |
| tsz = maxsz; |
| if ((tp = realloc(*dst, tsz)) == NULL) |
| return -1; |
| *dp = tp + (*dp - *dst); |
| *dst = tp; |
| *sz = tsz; |
| return 0; |
| } |
| |
| /* |
| * The following two functions limit the number of bytes written, |
| * including the terminating '\0', to sz. Unless wp is NULL, |
| * they limit the number of display columns occupied to *wp. |
| * Whichever is reached first terminates the output string. |
| * To stay close to the standard interfaces, they return the number of |
| * non-NUL bytes that would have been written if both were unlimited. |
| * If wp is NULL, newline, carriage return, and tab are allowed; |
| * otherwise, the actual number of columns occupied by what was |
| * written is returned in *wp. |
| */ |
| |
| static int |
| vasnmprintf(char **str, size_t maxsz, int *wp, const char *fmt, va_list ap) |
| { |
| char *src; /* Source string returned from vasprintf. */ |
| char *sp; /* Pointer into src. */ |
| char *dst; /* Destination string to be returned. */ |
| char *dp; /* Pointer into dst. */ |
| char *tp; /* Temporary pointer for dst. */ |
| size_t sz; /* Number of bytes allocated for dst. */ |
| wchar_t wc; /* Wide character at sp. */ |
| int len; /* Number of bytes in the character at sp. */ |
| int ret; /* Number of bytes needed to format src. */ |
| int width; /* Display width of the character wc. */ |
| int total_width, max_width, print; |
| |
| src = NULL; |
| if ((ret = vasprintf(&src, fmt, ap)) <= 0) |
| goto fail; |
| |
| sz = strlen(src) + 1; |
| if ((dst = malloc(sz)) == NULL) { |
| free(src); |
| ret = -1; |
| goto fail; |
| } |
| |
| if (maxsz > INT_MAX) |
| maxsz = INT_MAX; |
| |
| sp = src; |
| dp = dst; |
| ret = 0; |
| print = 1; |
| total_width = 0; |
| max_width = wp == NULL ? INT_MAX : *wp; |
| while (*sp != '\0') { |
| if ((len = mbtowc(&wc, sp, MB_CUR_MAX)) == -1) { |
| (void)mbtowc(NULL, NULL, MB_CUR_MAX); |
| if (dangerous_locale()) { |
| ret = -1; |
| break; |
| } |
| len = 1; |
| width = -1; |
| } else if (wp == NULL && |
| (wc == L'\n' || wc == L'\r' || wc == L'\t')) { |
| /* |
| * Don't use width uninitialized; the actual |
| * value doesn't matter because total_width |
| * is only returned for wp != NULL. |
| */ |
| width = 0; |
| } else if ((width = wcwidth(wc)) == -1 && |
| dangerous_locale()) { |
| ret = -1; |
| break; |
| } |
| |
| /* Valid, printable character. */ |
| |
| if (width >= 0) { |
| if (print && (dp - dst >= (int)maxsz - len || |
| total_width > max_width - width)) |
| print = 0; |
| if (print) { |
| if (grow_dst(&dst, &sz, maxsz, |
| &dp, len) == -1) { |
| ret = -1; |
| break; |
| } |
| total_width += width; |
| memcpy(dp, sp, len); |
| dp += len; |
| } |
| sp += len; |
| if (ret >= 0) |
| ret += len; |
| continue; |
| } |
| |
| /* Escaping required. */ |
| |
| while (len > 0) { |
| if (print && (dp - dst >= (int)maxsz - 4 || |
| total_width > max_width - 4)) |
| print = 0; |
| if (print) { |
| if (grow_dst(&dst, &sz, maxsz, |
| &dp, 4) == -1) { |
| ret = -1; |
| break; |
| } |
| tp = vis(dp, *sp, VIS_OCTAL | VIS_ALL, 0); |
| width = tp - dp; |
| total_width += width; |
| dp = tp; |
| } else |
| width = 4; |
| len--; |
| sp++; |
| if (ret >= 0) |
| ret += width; |
| } |
| if (len > 0) |
| break; |
| } |
| free(src); |
| *dp = '\0'; |
| *str = dst; |
| if (wp != NULL) |
| *wp = total_width; |
| |
| /* |
| * If the string was truncated by the width limit but |
| * would have fit into the size limit, the only sane way |
| * to report the problem is using the return value, such |
| * that the usual idiom "if (ret < 0 || ret >= sz) error" |
| * works as expected. |
| */ |
| |
| if (ret < (int)maxsz && !print) |
| ret = -1; |
| return ret; |
| |
| fail: |
| if (wp != NULL) |
| *wp = 0; |
| if (ret == 0) { |
| *str = src; |
| return 0; |
| } else { |
| *str = NULL; |
| return -1; |
| } |
| } |
| |
| int |
| snmprintf(char *str, size_t sz, int *wp, const char *fmt, ...) |
| { |
| va_list ap; |
| char *cp; |
| int ret; |
| |
| va_start(ap, fmt); |
| ret = vasnmprintf(&cp, sz, wp, fmt, ap); |
| va_end(ap); |
| if (cp != NULL) { |
| (void)strlcpy(str, cp, sz); |
| free(cp); |
| } else |
| *str = '\0'; |
| return ret; |
| } |
| |
| /* |
| * To stay close to the standard interfaces, the following functions |
| * return the number of non-NUL bytes written. |
| */ |
| |
| int |
| vfmprintf(FILE *stream, const char *fmt, va_list ap) |
| { |
| char *str; |
| int ret; |
| |
| if ((ret = vasnmprintf(&str, INT_MAX, NULL, fmt, ap)) < 0) |
| return -1; |
| if (fputs(str, stream) == EOF) |
| ret = -1; |
| free(str); |
| return ret; |
| } |
| |
| int |
| fmprintf(FILE *stream, const char *fmt, ...) |
| { |
| va_list ap; |
| int ret; |
| |
| va_start(ap, fmt); |
| ret = vfmprintf(stream, fmt, ap); |
| va_end(ap); |
| return ret; |
| } |
| |
| int |
| mprintf(const char *fmt, ...) |
| { |
| va_list ap; |
| int ret; |
| |
| va_start(ap, fmt); |
| ret = vfmprintf(stdout, fmt, ap); |
| va_end(ap); |
| return ret; |
| } |
| |
| /* |
| * Set up libc for multibyte output in the user's chosen locale. |
| * |
| * XXX: we are known to have problems with Turkish (i/I confusion) so we |
| * deliberately fall back to the C locale for now. Longer term we should |
| * always prefer to select C.[encoding] if possible, but there's no |
| * standardisation in locales between systems, so we'll need to survey |
| * what's out there first. |
| */ |
| void |
| msetlocale(void) |
| { |
| const char *vars[] = { "LC_ALL", "LC_CTYPE", "LANG", NULL }; |
| char *cp; |
| int i; |
| |
| /* |
| * We can't yet cope with dotless/dotted I in Turkish locales, |
| * so fall back to the C locale for these. |
| */ |
| for (i = 0; vars[i] != NULL; i++) { |
| if ((cp = getenv(vars[i])) == NULL) |
| continue; |
| if (strncasecmp(cp, "TR", 2) != 0) |
| break; |
| /* |
| * If we're in a UTF-8 locale then prefer to use |
| * the C.UTF-8 locale (or equivalent) if it exists. |
| */ |
| if ((strcasestr(cp, "UTF-8") != NULL || |
| strcasestr(cp, "UTF8") != NULL) && |
| (setlocale(LC_CTYPE, "C.UTF-8") != NULL || |
| setlocale(LC_CTYPE, "POSIX.UTF-8") != NULL)) |
| return; |
| setlocale(LC_CTYPE, "C"); |
| return; |
| } |
| /* We can handle this locale */ |
| setlocale(LC_CTYPE, ""); |
| } |