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![Nguyễn Thái Ngọc Duy](/assets/img/avatar_default.png)
Bug 6530 [1] in glibc causes "git show v0.99.6~1" to fail with error "your vsnprintf is broken". The workaround avoids that, but it corrupts system error messages in non-C locales. The bug has been fixed since 2.17. We could know running glibc version with gnu_get_libc_version(). But version is not a sure way to detect the bug because downstream may back port the fix to older versions. Do a runtime test that immitates the call flow that leads to "your vsnprintf is broken". Only enable the workaround if the test fails. Tested on Gentoo Linux, glibc 2.16.0 and 2.17, amd64. [1] http://sourceware.org/bugzilla/show_bug.cgi?id=6530 Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
154 lines
4.3 KiB
C
154 lines
4.3 KiB
C
/*
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* Copyright (c) 2010 Ævar Arnfjörð Bjarmason
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*/
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#include "git-compat-util.h"
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#include "gettext.h"
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#include "strbuf.h"
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#include "utf8.h"
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#ifndef NO_GETTEXT
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# include <locale.h>
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# include <libintl.h>
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# ifdef HAVE_LIBCHARSET_H
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# include <libcharset.h>
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# else
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# include <langinfo.h>
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# define locale_charset() nl_langinfo(CODESET)
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# endif
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#endif
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#ifdef GETTEXT_POISON
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int use_gettext_poison(void)
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{
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static int poison_requested = -1;
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if (poison_requested == -1)
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poison_requested = getenv("GIT_GETTEXT_POISON") ? 1 : 0;
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return poison_requested;
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}
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#endif
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#ifndef NO_GETTEXT
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static int test_vsnprintf(const char *fmt, ...)
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{
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char buf[26];
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int ret;
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va_list ap;
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va_start(ap, fmt);
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ret = vsnprintf(buf, sizeof(buf), fmt, ap);
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va_end(ap);
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return ret;
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}
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static const char *charset;
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static void init_gettext_charset(const char *domain)
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{
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/*
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This trick arranges for messages to be emitted in the user's
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requested encoding, but avoids setting LC_CTYPE from the
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environment for the whole program.
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This primarily done to avoid a bug in vsnprintf in the GNU C
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Library [1]. which triggered a "your vsnprintf is broken" error
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on Git's own repository when inspecting v0.99.6~1 under a UTF-8
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locale.
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That commit contains a ISO-8859-1 encoded author name, which
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the locale aware vsnprintf(3) won't interpolate in the format
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argument, due to mismatch between the data encoding and the
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locale.
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Even if it wasn't for that bug we wouldn't want to use LC_CTYPE at
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this point, because it'd require auditing all the code that uses C
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functions whose semantics are modified by LC_CTYPE.
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But only setting LC_MESSAGES as we do creates a problem, since
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we declare the encoding of our PO files[2] the gettext
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implementation will try to recode it to the user's locale, but
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without LC_CTYPE it'll emit something like this on 'git init'
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under the Icelandic locale:
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Bj? til t?ma Git lind ? /hlagh/.git/
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Gettext knows about the encoding of our PO file, but we haven't
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told it about the user's encoding, so all the non-US-ASCII
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characters get encoded to question marks.
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But we're in luck! We can set LC_CTYPE from the environment
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only while we call nl_langinfo and
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bind_textdomain_codeset. That suffices to tell gettext what
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encoding it should emit in, so it'll now say:
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Bjó til tóma Git lind í /hlagh/.git/
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And the equivalent ISO-8859-1 string will be emitted under a
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ISO-8859-1 locale.
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With this change way we get the advantages of setting LC_CTYPE
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(talk to the user in his language/encoding), without the major
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drawbacks (changed semantics for C functions we rely on).
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However foreign functions using other message catalogs that
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aren't using our neat trick will still have a problem, e.g. if
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we have to call perror(3):
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#include <stdio.h>
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#include <locale.h>
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#include <errno.h>
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int main(void)
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{
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setlocale(LC_MESSAGES, "");
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setlocale(LC_CTYPE, "C");
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errno = ENODEV;
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perror("test");
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return 0;
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}
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Running that will give you a message with question marks:
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$ LANGUAGE= LANG=de_DE.utf8 ./test
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test: Kein passendes Ger?t gefunden
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The vsnprintf bug has been fixed since glibc 2.17.
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Then we could simply set LC_CTYPE from the environment, which would
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make things like the external perror(3) messages work.
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See t/t0203-gettext-setlocale-sanity.sh's "gettext.c" tests for
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regression tests.
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1. http://sourceware.org/bugzilla/show_bug.cgi?id=6530
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2. E.g. "Content-Type: text/plain; charset=UTF-8\n" in po/is.po
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*/
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setlocale(LC_CTYPE, "");
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charset = locale_charset();
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bind_textdomain_codeset(domain, charset);
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/* the string is taken from v0.99.6~1 */
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if (test_vsnprintf("%.*s", 13, "David_K\345gedal") < 0)
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setlocale(LC_CTYPE, "C");
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}
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void git_setup_gettext(void)
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{
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const char *podir = getenv("GIT_TEXTDOMAINDIR");
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if (!podir)
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podir = GIT_LOCALE_PATH;
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bindtextdomain("git", podir);
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setlocale(LC_MESSAGES, "");
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init_gettext_charset("git");
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textdomain("git");
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}
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/* return the number of columns of string 's' in current locale */
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int gettext_width(const char *s)
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{
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static int is_utf8 = -1;
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if (is_utf8 == -1)
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is_utf8 = !strcmp(charset, "UTF-8");
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return is_utf8 ? utf8_strwidth(s) : strlen(s);
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}
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#endif
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