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- /*
- * Copyright (c) Ian F. Darwin 1986-1995.
- * Software written by Ian F. Darwin and others;
- * maintained 1995-present by Christos Zoulas and others.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice immediately at the beginning of the file, without modification,
- * this list of conditions, and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
- * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- /*
- * ASCII magic -- try to detect text encoding.
- *
- * Extensively modified by Eric Fischer <enf@pobox.com> in July, 2000,
- * to handle character codes other than ASCII on a unified basis.
- */
- #include "file.h"
- #ifndef lint
- FILE_RCSID("@(#)$File: ascmagic.c,v 1.116 2023/05/21 16:08:50 christos Exp $")
- #endif /* lint */
- #include "magic.h"
- #include <string.h>
- #include <ctype.h>
- #include <stdlib.h>
- #ifdef HAVE_UNISTD_H
- #include <unistd.h>
- #endif
- #define MAXLINELEN 300 /* longest sane line length */
- #define ISSPC(x) ((x) == ' ' || (x) == '\t' || (x) == '\r' || (x) == '\n' \
- || (x) == 0x85 || (x) == '\f')
- file_private unsigned char *encode_utf8(unsigned char *, size_t, file_unichar_t *,
- size_t);
- file_private size_t trim_nuls(const unsigned char *, size_t);
- /*
- * Undo the NUL-termination kindly provided by process()
- * but leave at least one byte to look at
- */
- file_private size_t
- trim_nuls(const unsigned char *buf, size_t nbytes)
- {
- while (nbytes > 1 && buf[nbytes - 1] == '\0')
- nbytes--;
- return nbytes;
- }
- file_protected int
- file_ascmagic(struct magic_set *ms, const struct buffer *b, int text)
- {
- file_unichar_t *ubuf = NULL;
- size_t ulen = 0;
- int rv = 1;
- struct buffer bb;
- const char *code = NULL;
- const char *code_mime = NULL;
- const char *type = NULL;
- bb = *b;
- bb.flen = trim_nuls(CAST(const unsigned char *, b->fbuf), b->flen);
- /*
- * Avoid trimming at an odd byte if the original buffer was evenly
- * sized; this avoids losing the last character on UTF-16 LE text
- */
- if ((bb.flen & 1) && !(b->flen & 1))
- bb.flen++;
- /* If file doesn't look like any sort of text, give up. */
- if (file_encoding(ms, &bb, &ubuf, &ulen, &code, &code_mime,
- &type) == 0)
- rv = 0;
- else
- rv = file_ascmagic_with_encoding(ms, &bb,
- ubuf, ulen, code, type, text);
- free(ubuf);
- return rv;
- }
- file_protected int
- file_ascmagic_with_encoding(struct magic_set *ms, const struct buffer *b,
- file_unichar_t *ubuf, size_t ulen, const char *code, const char *type,
- int text)
- {
- struct buffer bb;
- const unsigned char *buf = CAST(const unsigned char *, b->fbuf);
- size_t nbytes = b->flen;
- unsigned char *utf8_buf = NULL, *utf8_end;
- size_t mlen, i, len;
- int rv = -1;
- int mime = ms->flags & MAGIC_MIME;
- int need_separator = 0;
- const char *subtype = NULL;
- int has_escapes = 0;
- int has_backspace = 0;
- int seen_cr = 0;
- size_t n_crlf = 0;
- size_t n_lf = 0;
- size_t n_cr = 0;
- size_t n_nel = 0;
- int executable = 0;
- size_t last_line_end = CAST(size_t, -1);
- size_t has_long_lines = 0;
- nbytes = trim_nuls(buf, nbytes);
- /* If we have fewer than 2 bytes, give up. */
- if (nbytes <= 1) {
- rv = 0;
- goto done;
- }
- if (ulen > 0 && (ms->flags & MAGIC_NO_CHECK_SOFT) == 0) {
- /* Convert ubuf to UTF-8 and try text soft magic */
- /* malloc size is a conservative overestimate; could be
- improved, or at least realloced after conversion. */
- mlen = ulen * 6;
- if ((utf8_buf = CAST(unsigned char *, malloc(mlen))) == NULL) {
- file_oomem(ms, mlen);
- goto done;
- }
- if ((utf8_end = encode_utf8(utf8_buf, mlen, ubuf, ulen))
- == NULL) {
- rv = 0;
- goto done;
- }
- buffer_init(&bb, b->fd, &b->st, utf8_buf,
- CAST(size_t, utf8_end - utf8_buf));
- if ((rv = file_softmagic(ms, &bb, NULL, NULL,
- TEXTTEST, text)) == 0)
- rv = -1;
- else
- need_separator = 1;
- buffer_fini(&bb);
- if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION))) {
- rv = rv == -1 ? 0 : 1;
- goto done;
- }
- }
- if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION))) {
- rv = 0;
- goto done;
- }
- /* Now try to discover other details about the file. */
- for (i = 0; i < ulen; i++) {
- if (ubuf[i] == '\n') {
- if (seen_cr)
- n_crlf++;
- else
- n_lf++;
- last_line_end = i;
- } else if (seen_cr)
- n_cr++;
- seen_cr = (ubuf[i] == '\r');
- if (seen_cr)
- last_line_end = i;
- if (ubuf[i] == 0x85) { /* X3.64/ECMA-43 "next line" character */
- n_nel++;
- last_line_end = i;
- }
- /* If this line is _longer_ than MAXLINELEN, remember it. */
- if (i > last_line_end + MAXLINELEN) {
- size_t ll = i - last_line_end;
- if (ll > has_long_lines)
- has_long_lines = ll;
- }
- if (ubuf[i] == '\033')
- has_escapes = 1;
- if (ubuf[i] == '\b')
- has_backspace = 1;
- }
- if (strcmp(type, "binary") == 0) {
- rv = 0;
- goto done;
- }
- len = file_printedlen(ms);
- if (mime) {
- if ((mime & MAGIC_MIME_TYPE) != 0) {
- if (len) {
- /*
- * Softmagic printed something, we
- * are either done, or we need a separator
- */
- if ((ms->flags & MAGIC_CONTINUE) == 0) {
- rv = 1;
- goto done;
- }
- if (need_separator && file_separator(ms) == -1)
- goto done;
- }
- if (file_printf(ms, "text/plain") == -1)
- goto done;
- }
- } else {
- if (len) {
- switch (file_replace(ms, " text$", ", ")) {
- case 0:
- switch (file_replace(ms, " text executable$",
- ", ")) {
- case 0:
- if (file_printf(ms, ", ") == -1)
- goto done;
- break;
- case -1:
- goto done;
- default:
- executable = 1;
- break;
- }
- break;
- case -1:
- goto done;
- default:
- break;
- }
- }
- if (file_printf(ms, "%s", code) == -1)
- goto done;
- if (subtype) {
- if (file_printf(ms, " %s", subtype) == -1)
- goto done;
- }
- if (file_printf(ms, " %s", type) == -1)
- goto done;
- if (executable)
- if (file_printf(ms, " executable") == -1)
- goto done;
- if (has_long_lines)
- if (file_printf(ms, ", with very long lines (%"
- SIZE_T_FORMAT "u)", has_long_lines) == -1)
- goto done;
- /*
- * Only report line terminators if we find one other than LF,
- * or if we find none at all.
- */
- if ((n_crlf == 0 && n_cr == 0 && n_nel == 0 && n_lf == 0) ||
- (n_crlf != 0 || n_cr != 0 || n_nel != 0)) {
- if (file_printf(ms, ", with") == -1)
- goto done;
- if (n_crlf == 0 && n_cr == 0 &&
- n_nel == 0 && n_lf == 0) {
- if (file_printf(ms, " no") == -1)
- goto done;
- } else {
- if (n_crlf) {
- if (file_printf(ms, " CRLF") == -1)
- goto done;
- if (n_cr || n_lf || n_nel)
- if (file_printf(ms, ",") == -1)
- goto done;
- }
- if (n_cr) {
- if (file_printf(ms, " CR") == -1)
- goto done;
- if (n_lf || n_nel)
- if (file_printf(ms, ",") == -1)
- goto done;
- }
- if (n_lf) {
- if (file_printf(ms, " LF") == -1)
- goto done;
- if (n_nel)
- if (file_printf(ms, ",") == -1)
- goto done;
- }
- if (n_nel)
- if (file_printf(ms, " NEL") == -1)
- goto done;
- }
- if (file_printf(ms, " line terminators") == -1)
- goto done;
- }
- if (has_escapes)
- if (file_printf(ms, ", with escape sequences") == -1)
- goto done;
- if (has_backspace)
- if (file_printf(ms, ", with overstriking") == -1)
- goto done;
- }
- rv = 1;
- done:
- free(utf8_buf);
- return rv;
- }
- /*
- * Encode Unicode string as UTF-8, returning pointer to character
- * after end of string, or NULL if an invalid character is found.
- */
- file_private unsigned char *
- encode_utf8(unsigned char *buf, size_t len, file_unichar_t *ubuf, size_t ulen)
- {
- size_t i;
- unsigned char *end = buf + len;
- for (i = 0; i < ulen; i++) {
- if (ubuf[i] <= 0x7f) {
- if (end - buf < 1)
- return NULL;
- *buf++ = CAST(unsigned char, ubuf[i]);
- continue;
- }
- if (ubuf[i] <= 0x7ff) {
- if (end - buf < 2)
- return NULL;
- *buf++ = CAST(unsigned char, (ubuf[i] >> 6) + 0xc0);
- goto out1;
- }
- if (ubuf[i] <= 0xffff) {
- if (end - buf < 3)
- return NULL;
- *buf++ = CAST(unsigned char, (ubuf[i] >> 12) + 0xe0);
- goto out2;
- }
- if (ubuf[i] <= 0x1fffff) {
- if (end - buf < 4)
- return NULL;
- *buf++ = CAST(unsigned char, (ubuf[i] >> 18) + 0xf0);
- goto out3;
- }
- if (ubuf[i] <= 0x3ffffff) {
- if (end - buf < 5)
- return NULL;
- *buf++ = CAST(unsigned char, (ubuf[i] >> 24) + 0xf8);
- goto out4;
- }
- if (ubuf[i] <= 0x7fffffff) {
- if (end - buf < 6)
- return NULL;
- *buf++ = CAST(unsigned char, (ubuf[i] >> 30) + 0xfc);
- goto out5;
- }
- /* Invalid character */
- return NULL;
- out5: *buf++ = CAST(unsigned char, ((ubuf[i] >> 24) & 0x3f) + 0x80);
- out4: *buf++ = CAST(unsigned char, ((ubuf[i] >> 18) & 0x3f) + 0x80);
- out3: *buf++ = CAST(unsigned char, ((ubuf[i] >> 12) & 0x3f) + 0x80);
- out2: *buf++ = CAST(unsigned char, ((ubuf[i] >> 6) & 0x3f) + 0x80);
- out1: *buf++ = CAST(unsigned char, ((ubuf[i] >> 0) & 0x3f) + 0x80);
- }
- return buf;
- }
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