Hi Eric, Following your suggestion, I tried to use fstatvfs() to get filesystem type, but i didn't find which field can be used to do that. The OS system is Mac OS Mavericks, the project lied in a TrueCrypt volume which was formatted as FAT filesystem.
% uname -a Darwin zgx.local 13.1.0 Darwin Kernel Version 13.1.0: Thu Jan 16 19:40:37 PST 2014; root:xnu-2422.90.20~2/RELEASE_X86_64 x86_64 % mount | grep msdos /dev/disk1 on /Users/zouguangxian/Volumes/Windows7X (msdos, local, nodev, nosuid, noowners, mounted by zouguangxian) % automake --version automake (GNU automake) 1.14.1 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl-2.0.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by Tom Tromey <tro...@redhat.com> and Alexandre Duret-Lutz <a...@gnu.org>. % autoconf --version autoconf (GNU Autoconf) 2.69 Copyright (C) 2012 Free Software Foundation, Inc. License GPLv3+/Autoconf: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>, <http://gnu.org/licenses/exceptions.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by David J. MacKenzie and Akim Demaille. the patch is: % diff -u m4-1.4.17.orig/src/debug.c m4-1.4.17/src/debug.c --- m4-1.4.17.orig/src/debug.c 2013-09-22 13:50:43.000000000 +0800 +++ m4-1.4.17/src/debug.c 2014-05-01 13:44:24.000000000 +0800 @@ -23,6 +23,8 @@ #include <stdarg.h> #include <sys/stat.h> +#include <sys/param.h> +#include <sys/mount.h> /* File for debugging output. */ FILE *debug = NULL; @@ -151,6 +153,20 @@ && stdout_stat.st_dev == debug_stat.st_dev && stdout_stat.st_ino != 0) { + /* on fat file systems, zero-length files share this magic value */ + if (debug_stat.st_ino == 999999999) + { + struct statfs sfsb; + if (fstatfs (fileno (debug), &sfsb) == 0) + { + if (strcasecmp (sfsb.f_fstypename, "msdos") == 0 + || strcasecmp (sfsb.f_fstypename, "exfat") == 0) + { + return; + } + } + } + if (debug != stderr && close_stream (debug) != 0) { M4ERROR ((warning_status, errno, ---- Zou Guangxian 2014-05-01 12:31 GMT+08:00 Eric Blake <ebl...@redhat.com>: > On 04/30/2014 10:10 PM, 光先邹 wrote: > >> >> The reason is st_ino of empty file in FAT system is 999999999, which will >> lead debug set back to stdout in function debug_set_file. Here is a patch >> which will resolve this problem. > > Thanks for the report. However, I'd rather you get the filesystem bug > fixed rather than trying to patch lots of individual programs that are > all negatively impacted by the filesystem bug. > >> >> >> % diff -u m4-1.4.17.orig/src/debug.c m4-1.4.17/src/debug.c >> >> --- m4-1.4.17.orig/src/debug.c 2013-09-22 13:50:43.000000000 +0800 >> >> +++ m4-1.4.17/src/debug.c 2014-05-01 11:55:41.000000000 +0800 >> >> @@ -23,6 +23,8 @@ >> > > Your patch came through with whitespace munging; any chance you can > convince your mailer to send it in a way that won't be corrupted in transit? > >> >> #include <stdarg.h> >> >> #include <sys/stat.h> >> >> +#include <sys/param.h> >> >> +#include <sys/mount.h> >> > > These files are not POSIX, and therefore cannot be expected to exist on > all platforms. To use them, you'd first have to add configure.ac checks > on whether they exist. > > >> >> + if(debug_stat.st_ino == 999999999) > > Style: space before ( > >> >> + { >> >> + struct statfs sfsb; >> >> + if(fstatfs(fileno (debug), &sfsb) == 0) > > and again > >> >> + { >> >> + if (strcasecmp(sfsb.f_fstypename, "msdos") == 0 > > and again. > > f_fstypename is not a portable member of struct statfs; more configure > checks are required. In fact, fstatfs() is not portable; POSIX only > requires fstatvfs(). I need more details about your setup - which > kernel are you using, and which version of the fat filesystem? > > Again, this feels too hacky to include in m4 proper; the real bug is in > the file system for violating POSIX semantics on returning an inode > number that reliably determines a unique file. > > -- > Eric Blake eblake redhat com +1-919-301-3266 > Libvirt virtualization library http://libvirt.org >
