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+/*
+ * manconv.c: convert manual page from one encoding to another
+ *
+ * Copyright (C) 2007, 2008, 2009, 2010, 2012 Colin Watson.
+ * Based loosely on parts of glibc's iconv_prog.c, which is:
+ * Copyright (C) 1998-2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+ *
+ * This file is part of man-db.
+ *
+ * man-db is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * man-db 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with man-db; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/* This program arose during a discussion with Adam Borowski. See:
+ * https://lists.debian.org/debian-mentors/2007/09/msg00245.html
+ * It behaves like iconv, but allows multiple source encodings and
+ * attempts to guess the first one that works. An Emacs-style
+ * "-*- coding:" declaration overrides this.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#ifdef HAVE_ICONV
+# include <iconv.h>
+#endif /* HAVE_ICONV */
+
+#include "argp.h"
+
+#include "gettext.h"
+#include <locale.h>
+#define _(String) gettext (String)
+
+#include "manconfig.h"
+
+#include "error.h"
+#include "pipeline.h"
+#include "encodings.h"
+
+#include "manconv.h"
+
+#ifdef HAVE_ICONV
+
+/* When converting text containing an invalid multibyte sequence to
+ * UTF-8//IGNORE, GNU libc's iconv returns EILSEQ but sets *inbuf to the end
+ * of the input buffer. I'm not sure whether this is a bug or not (it seems
+ * to contradict the documentation), but work around it anyway by recoding
+ * to UTF-8 so that we can accurately position the error.
+ */
+static off_t locate_error (const char *try_from_code,
+ const char *input, size_t input_size,
+ char *utf8, size_t utf8_size)
+{
+ iconv_t cd_utf8_strict;
+ char *inptr = (char *) input, *utf8ptr = utf8;
+ size_t inleft = input_size, utf8left = utf8_size;
+ size_t n;
+ off_t ret;
+
+ cd_utf8_strict = iconv_open ("UTF-8", try_from_code);
+ if (cd_utf8_strict == (iconv_t) -1) {
+ error (0, errno, "iconv_open (\"UTF-8\", \"%s\")",
+ try_from_code);
+ return 0;
+ }
+
+ n = iconv (cd_utf8_strict, (ICONV_CONST char **) &inptr, &inleft,
+ &utf8ptr, &utf8left);
+ if (n == (size_t) -1)
+ ret = inptr - input;
+ else
+ ret = 0;
+
+ iconv_close (cd_utf8_strict);
+
+ return ret;
+}
+
+static int try_iconv (pipeline *p, const char *try_from_code, const char *to,
+ int last)
+{
+ char *try_to_code = xstrdup (to);
+ static const size_t buf_size = 65536;
+ size_t input_size = buf_size;
+ off_t input_pos = 0;
+ const char *input;
+ static char *utf8 = NULL, *output = NULL;
+ size_t utf8left = 0;
+ iconv_t cd_utf8, cd = NULL;
+ int to_utf8 = STREQ (try_to_code, "UTF-8") ||
+ STRNEQ (try_to_code, "UTF-8//", 7);
+ const char *utf8_target = last ? "UTF-8//IGNORE" : "UTF-8";
+ int ignore_errors = (strstr (try_to_code, "//IGNORE") != NULL);;
+ int ret = 0;
+
+ debug ("trying encoding %s -> %s\n", try_from_code, try_to_code);
+
+ cd_utf8 = iconv_open (utf8_target, try_from_code);
+ if (cd_utf8 == (iconv_t) -1) {
+ error (0, errno, "iconv_open (\"%s\", \"%s\")",
+ utf8_target, try_from_code);
+ free (try_to_code);
+ return -1;
+ }
+
+ if (!to_utf8) {
+ cd = iconv_open (try_to_code, "UTF-8");
+ if (cd == (iconv_t) -1) {
+ error (0, errno, "iconv_open (\"%s\", \"UTF-8\")",
+ try_to_code);
+ free (try_to_code);
+ return -1;
+ }
+ }
+
+ input = pipeline_peek (p, &input_size);
+ if (input_size < buf_size) {
+ /* End of file, error, or just a short read? Repeat until we
+ * have either a full buffer or EOF/error.
+ */
+ while (input_size < buf_size) {
+ size_t old_input_size = input_size;
+ input_size = buf_size;
+ input = pipeline_peek (p, &input_size);
+ if (input_size == old_input_size)
+ break;
+ }
+ }
+
+ if (!utf8)
+ utf8 = xmalloc (buf_size);
+ if (!output)
+ output = xmalloc (buf_size);
+
+ while (input_size || utf8left) {
+ int handle_iconv_errors = 0;
+ char *inptr = (char *) input, *utf8ptr = utf8;
+ char *outptr = output;
+ size_t inleft = input_size, outleft;
+ size_t n, n2 = -1;
+
+ if (!utf8left) {
+ /* First, convert the text to UTF-8. By assumption,
+ * all validly-encoded text can be converted to
+ * UTF-8 assuming that we picked the correct
+ * encoding. Any errors at this stage are due to
+ * selecting an incorrect encoding, or due to
+ * misencoded source text.
+ */
+ utf8left = buf_size;
+ n = iconv (cd_utf8, (ICONV_CONST char **) &inptr,
+ &inleft, &utf8ptr, &utf8left);
+ utf8left = buf_size - utf8left;
+
+ /* If we need to try the next encoding, do that
+ * before writing anything.
+ */
+ if (!last && n == (size_t) -1 &&
+ (errno == EILSEQ ||
+ (errno == EINVAL && input_size < buf_size))) {
+ ret = -1;
+ break;
+ } else if (n == (size_t) -1)
+ handle_iconv_errors = errno;
+ }
+
+ /* If the target encoding is UTF-8 (the common case), then
+ * we can just write out what we've got. Otherwise, we need
+ * to convert to the target encoding. Any errors at this
+ * stage are due to characters that are not representable in
+ * the target encoding.
+ */
+ if (handle_iconv_errors)
+ /* Fall back to error handling below. If we have
+ * anything to write out, we'll do it next time
+ * round the loop.
+ */
+ ;
+ else if (to_utf8) {
+ memcpy (output, utf8, utf8left);
+ outptr += utf8left;
+ outleft = utf8left;
+ utf8left = 0;
+ } else if (utf8left) {
+ outptr = output;
+ outleft = buf_size;
+ utf8ptr = utf8;
+ n2 = iconv (
+ cd, (ICONV_CONST char **) &utf8ptr, &utf8left,
+ &outptr, &outleft);
+ outleft = buf_size - outleft;
+ if (n2 == (size_t) -1)
+ handle_iconv_errors = errno;
+
+ if (n2 == (size_t) -1 &&
+ errno == EILSEQ && ignore_errors)
+ errno = 0;
+ } else
+ /* We appear to have converted some input text, but
+ * not actually ended up with any UTF-8 text. This
+ * is odd. However, we can at least continue round
+ * the loop, skip the input text we converted, and
+ * then we should get a different result next time.
+ */
+ outptr = output;
+
+ if (outptr != output) {
+ /* We have something to write out. */
+ int errno_save = errno;
+ size_t w;
+ w = fwrite (output, 1, outleft, stdout);
+ if (w < (size_t) outleft || ferror (stdout))
+ error (FATAL, 0, _("can't write to "
+ "standard output"));
+ errno = errno_save;
+ }
+
+ if (!to_utf8 && n2 != (size_t) -1) {
+ /* All the UTF-8 text we have so far was processed.
+ * For state-dependent character sets we have to
+ * flush the state now.
+ */
+ outptr = output;
+ outleft = buf_size;
+ iconv (cd, NULL, NULL, &outptr, &outleft);
+ outleft = buf_size - outleft;
+
+ if (outptr != output) {
+ /* We have something to write out. */
+ int errno_save = errno;
+ size_t w;
+ w = fwrite (output, 1, outleft, stdout);
+ if (w < (size_t) outleft || ferror (stdout))
+ error (FATAL, 0, _("can't write to "
+ "standard output"));
+ errno = errno_save;
+ }
+ } else if (handle_iconv_errors) {
+ intmax_t error_pos;
+
+ if (handle_iconv_errors == EILSEQ && !ignore_errors) {
+ if (!quiet) {
+ error_pos = input_pos + locate_error (
+ try_from_code,
+ input, input_size,
+ utf8, buf_size);
+ error (0, handle_iconv_errors,
+ "byte %jd: iconv", error_pos);
+ }
+ exit (FATAL);
+ } else if (handle_iconv_errors == EINVAL &&
+ input_size < buf_size) {
+ if (!quiet) {
+ error_pos = input_pos + locate_error (
+ try_from_code,
+ input, input_size,
+ utf8, buf_size);
+ error (FATAL, 0, "byte %jd: %s",
+ error_pos,
+ _("iconv: incomplete character "
+ "at end of buffer"));
+ }
+ exit (FATAL);
+ }
+ }
+
+ if (inptr != input) {
+ pipeline_peek_skip (p, input_size - inleft);
+ input_pos += input_size - inleft;
+ }
+
+ /* Unless we have some UTF-8 text left (which will only
+ * happen if the output encoding is more verbose than UTF-8,
+ * so is unlikely for legacy encodings), we need to fetch
+ * more input text now.
+ */
+ if (!utf8left) {
+ input_size = buf_size;
+ input = pipeline_peek (p, &input_size);
+ while (input_size < buf_size) {
+ size_t old_input_size = input_size;
+ input_size = buf_size;
+ input = pipeline_peek (p, &input_size);
+ if (input_size == old_input_size)
+ break;
+ }
+ }
+ }
+
+ if (!to_utf8)
+ iconv_close (cd);
+ iconv_close (cd_utf8);
+ free (try_to_code);
+
+ return ret;
+}
+
+void manconv (pipeline *p, char * const *from, const char *to)
+{
+ char *pp_encoding;
+ char * const *try_from_code;
+
+ pp_encoding = check_preprocessor_encoding (p);
+ if (pp_encoding) {
+ try_iconv (p, pp_encoding, to, 1);
+ free (pp_encoding);
+ } else {
+ for (try_from_code = from; *try_from_code; ++try_from_code)
+ if (try_iconv (p, *try_from_code, to,
+ !*(try_from_code + 1)) == 0)
+ break;
+ }
+}
+
+#else /* !HAVE_ICONV */
+
+/* If we don't have iconv, there isn't much we can do; just pass everything
+ * through unchanged.
+ */
+void manconv (pipeline *p, char * const *from ATTRIBUTE_UNUSED,
+ const char *to ATTRIBUTE_UNUSED)
+{
+ for (;;) {
+ size_t len = 4096;
+ const char *buffer = pipeline_read (p, &len);
+ if (len == 0)
+ break;
+ if (fwrite (buffer, 1, len, stdout) < len || ferror (stdout))
+ error (FATAL, 0, _("can't write to standard output"));
+ }
+}
+
+#endif /* HAVE_ICONV */
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