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Message-ID: <20190324142118.GS23599@brightrain.aerifal.cx>
Date: Sun, 24 Mar 2019 10:21:18 -0400
From: Rich Felker <dalias@...c.org>
To: musl@...ts.openwall.com
Subject: futimens on musl libc (fwd)
I think this needs action but I'm not clear what the exact mechanism
is yet, so I'm forwarding to the list.
----- Forwarded message from Bruno Haible <bruno@...sp.org> -----
From: Bruno Haible <bruno@...sp.org>
To: bug-gnulib@....org, Rich Felker <dalias@...c.org>
Subject: futimens on musl libc
Date: Sat, 23 Mar 2019 21:40:33 +0100
Message-ID: <4061903.SY8uJAIc8I@...ga>
The gnulib configure test in m4/futimens.m4, when run on Alpine Linux 3.7,
determines that the errno value is not as expected for a wrong fd.
Let me document this in gnulib and update the cross-compilation guess
accordingly.
Rich, FYI: The test program is this one:
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
int main ()
{
struct timespec ts[2];
int fd = creat ("conftest.file", 0600);
struct stat st;
if (fd < 0) return 1;
ts[0].tv_sec = 1;
ts[0].tv_nsec = UTIME_OMIT;
ts[1].tv_sec = 1;
ts[1].tv_nsec = UTIME_NOW;
errno = 0;
if (futimens (AT_FDCWD, NULL) == 0) return 2;
if (errno != EBADF) return 3; /* <== It fails here */
if (futimens (fd, ts)) return 4;
sleep (1);
ts[0].tv_nsec = UTIME_NOW;
ts[1].tv_nsec = UTIME_OMIT;
if (futimens (fd, ts)) return 5;
if (fstat (fd, &st)) return 6;
if (st.st_ctime < st.st_atime) return 7;
return 0;
}
2019-03-23 Bruno Haible <bruno@...sp.org>
futimens: Document musl libc bug.
* doc/posix-functions/futimens.texi: Mention the bug.
* m4/futimens.m4 (gl_FUNC_FUTIMENS): Require AC_CANONICAL_HOST. When
cross-compiling guess no on glibc and musl systems.
diff --git a/doc/posix-functions/futimens.texi b/doc/posix-functions/futimens.texi
index 19fb84e..1e1c76c 100644
--- a/doc/posix-functions/futimens.texi
+++ b/doc/posix-functions/futimens.texi
@@ -29,7 +29,7 @@ Linux kernel 2.6.32, Solaris 11.1.
@item
Passing @code{AT_FDCWD} as the fd argument does not properly fail with
@code{EBADF} on some systems:
-glibc 2.11, Solaris 11.
+glibc 2.11, musl libc, Solaris 11.
@end itemize
Portability problems not fixed by Gnulib:
diff --git a/m4/futimens.m4 b/m4/futimens.m4
index 3cfa4a1..b5f4be9 100644
--- a/m4/futimens.m4
+++ b/m4/futimens.m4
@@ -1,4 +1,4 @@
-# serial 7
+# serial 8
# See if we need to provide futimens replacement.
dnl Copyright (C) 2009-2019 Free Software Foundation, Inc.
@@ -11,6 +11,7 @@ dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_FUTIMENS],
[
AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_CHECK_FUNCS_ONCE([futimens])
if test $ac_cv_func_futimens = no; then
@@ -44,10 +45,21 @@ AC_DEFUN([gl_FUNC_FUTIMENS],
]])],
[gl_cv_func_futimens_works=yes],
[gl_cv_func_futimens_works=no],
- [gl_cv_func_futimens_works="guessing yes"])
+ [case "$host_os" in
+ # Guess no on glibc systems.
+ *-gnu* | gnu*) gl_cv_func_futimens_works="guessing no" ;;
+ # Guess no on musl systems.
+ *-musl*) gl_cv_func_futimens_works="guessing no" ;;
+ # Guess yes otherwise.
+ *) gl_cv_func_futimens_works="guessing yes" ;;
+ esac
+ ])
rm -f conftest.file])
- if test "$gl_cv_func_futimens_works" = no; then
- REPLACE_FUTIMENS=1
- fi
+ case "$gl_cv_func_futimens_works" in
+ *yes) ;;
+ *)
+ REPLACE_FUTIMENS=1
+ ;;
+ esac
fi
])
----- End forwarded message -----
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