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[bug-gnulib] Re: iconv made easy
From: |
Simon Josefsson |
Subject: |
[bug-gnulib] Re: iconv made easy |
Date: |
Tue, 28 Dec 2004 00:50:13 +0100 |
User-agent: |
Gnus/5.110003 (No Gnus v0.3) Emacs/21.3.50 (gnu/linux) |
Paul Eggert <address@hidden> writes:
> Simon Josefsson <address@hidden> writes:
>
>> + if (newsize <= outbuf_size
>> + || !(newdest = realloc (dest, newsize)))
>> + {
>> + have_error = 1;
>> + goto out;
>> + }
>
> If newsize <= outbuf_size, this sets have_error=1 and the remaining
> code eventually uses errno. But errno is garbage at that point. You
> need to set errno to ENOMEM in that case.
No, I believe errno would have been E2BIG if 'newsize <= outbuf_size'
trigger the if case. But I have changed it into:
if (newsize <= outbuf_size)
{
errno = EOVERFLOW;
have_error = 1;
goto out;
}
if (!(newdest = realloc (dest, newsize)))
{
have_error = 1;
goto out;
}
>> + if (iconv_close (cd) < 0)
>> + have_error = 1;
>> + else
>> + errno = save_errno;
>> +
>> + if (have_error && dest)
>> + {
>> + free (dest);
>> + dest = NULL;
>> + errno = save_errno;
>> + }
>
> Again, the resulting errno is incorrect if iconv_close returns a
> negative number and dest is nonzero.
New code reads:
{
int save_errno = errno;
if (iconv_close (cd) < 0)
{
/* If we didn't have a real error before, make sure we restore
the iconv_close error below. If we did have an error
before, we should restore that error, instead of the
iconv_close error, below. */
if (!have_error)
save_errno = errno;
have_error = 1;
}
if (have_error && dest)
{
free (dest);
dest = NULL;
errno = save_errno;
}
}
> It might not hurt for you to review all the paths to the code that
> uses errno, to make sure that it can't be garbage.
I tried to do it, but the code is rather hairy even at such a small
size.
>> I'm not sure about the cast of 'str' to 'ICONV_CONST char *'. Is
>> iconv guaranteed to not modify the input string content?
>
> I think so, but I think on some hosts the prototype is char * for
> historical reasons.
The POSIX prototype uses 'char **restrict'. I can't find any text
that say the function doesn't modify inbuf.
Thanks.
Index: lib/iconvme.c
===================================================================
RCS file: lib/iconvme.c
diff -N lib/iconvme.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ lib/iconvme.c 27 Dec 2004 23:50:05 -0000
@@ -0,0 +1,157 @@
+/* Recode strings between character sets, using iconv.
+ Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+
+ This program 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, or (at
+ your option) any later version.
+
+ This program 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 this program; if not, write to the Free Software Foundation,
+ Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Get prototype. */
+#include "iconvme.h"
+
+/* Get malloc. */
+#include <stdlib.h>
+
+/* Get strcmp. */
+#include <string.h>
+
+/* Get errno. */
+#include <errno.h>
+
+#if HAVE_ICONV
+/* Get iconv etc. */
+# include <iconv.h>
+/* Get MB_LEN_MAX. */
+# include <limits.h>
+#endif
+
+/* Get strdup. */
+#include "strdup.h"
+
+/* Convert a zero-terminated string STR from the FROM_CODSET code set
+ to the TO_CODESET code set. The returned string is allocated using
+ malloc, and must be dellocated by the caller using free. On
+ failure, NULL is returned and errno holds the error reason. Note
+ that if TO_CODESET uses \0 for anything but to terminate the
+ string, the caller of this function may have difficulties finding
+ out the length of the output string. */
+char *
+iconv_string (const char *str, const char *from_codeset,
+ const char *to_codeset)
+{
+ char *dest = NULL;
+#if HAVE_ICONV
+ iconv_t cd;
+ char *outp;
+ ICONV_CONST char *p = (ICONV_CONST char *) str;
+ size_t inbytes_remaining = strlen (p);
+ /* Guess the maximum length the output string can have. */
+ size_t outbuf_size = (inbytes_remaining + 1) * MB_LEN_MAX;
+ size_t outbytes_remaining = outbuf_size - 1; /* -1 for NUL */
+ size_t err;
+ int have_error = 0;
+#endif
+
+ if (strcmp (to_codeset, from_codeset) == 0)
+ return strdup (str);
+
+#if HAVE_ICONV
+ cd = iconv_open (to_codeset, from_codeset);
+ if (cd == (iconv_t) - 1)
+ return NULL;
+
+ outp = dest = malloc (outbuf_size);
+ if (dest == NULL)
+ goto out;
+
+again:
+ err = iconv (cd, &p, &inbytes_remaining, &outp, &outbytes_remaining);
+
+ if (err == (size_t) - 1)
+ {
+ switch (errno)
+ {
+ case EINVAL:
+ /* Incomplete text, do not report an error */
+ break;
+
+ case E2BIG:
+ {
+ size_t used = outp - dest;
+ size_t newsize = outbuf_size * 2;
+ char *newdest;
+
+ if (newsize <= outbuf_size)
+ {
+ errno = EOVERFLOW;
+ have_error = 1;
+ goto out;
+ }
+ if (!(newdest = realloc (dest, newsize)))
+ {
+ have_error = 1;
+ goto out;
+ }
+ dest = newdest;
+ outbuf_size = newsize;
+
+ outp = dest + used;
+ outbytes_remaining = outbuf_size - used - 1; /* -1 for NUL */
+
+ goto again;
+ }
+ break;
+
+ case EILSEQ:
+ have_error = 1;
+ break;
+
+ default:
+ have_error = 1;
+ break;
+ }
+ }
+
+ *outp = '\0';
+
+out:
+ {
+ int save_errno = errno;
+
+ if (iconv_close (cd) < 0)
+ {
+ /* If we didn't have a real error before, make sure we restore
+ the iconv_close error below. If we did have an error
+ before, we should restore that error, instead of the
+ iconv_close error, below. */
+ if (!have_error)
+ save_errno = errno;
+ have_error = 1;
+ }
+
+ if (have_error && dest)
+ {
+ free (dest);
+ dest = NULL;
+ errno = save_errno;
+ }
+ }
+#else
+ errno = ENOSYS;
+#endif
+
+ return dest;
+}
- [bug-gnulib] Re: iconv made easy, (continued)
- [bug-gnulib] Re: iconv made easy, Simon Josefsson, 2004/12/13
- [bug-gnulib] Re: iconv made easy, Simon Josefsson, 2004/12/15
- Re: [bug-gnulib] Re: iconv made easy, Paul Eggert, 2004/12/15
- [bug-gnulib] Re: iconv made easy, Simon Josefsson, 2004/12/15
- Re: [bug-gnulib] Re: iconv made easy, Paul Eggert, 2004/12/15
- [bug-gnulib] Re: iconv made easy, Simon Josefsson, 2004/12/15
- [bug-gnulib] Re: iconv made easy, Simon Josefsson, 2004/12/25
- Re: [bug-gnulib] Re: iconv made easy, Paul Eggert, 2004/12/26
- [bug-gnulib] Re: iconv made easy, Simon Josefsson, 2004/12/26
- [bug-gnulib] Re: iconv made easy, Paul Eggert, 2004/12/27
- [bug-gnulib] Re: iconv made easy,
Simon Josefsson <=
- [bug-gnulib] Re: iconv made easy, Paul Eggert, 2004/12/28
- [bug-gnulib] Re: iconv made easy, Simon Josefsson, 2004/12/28
- [bug-gnulib] Re: iconv made easy, Paul Eggert, 2004/12/28