From e03c60da0f4907cead18d8957cd78dbeec18ab23 Mon Sep 17 00:00:00 2001 From: Carl Worth Date: Tue, 4 Aug 2009 17:00:35 -0700 Subject: [PATCH] Preserve timestamp of symlinks when extracting (if utimensat available) If the utimensat function is not available, then do nothing with symlink time stamps, (which is the same as the current code). This closes Debian bug #313237, (thanks to D Goel for reporting it). --- debian/changelog | 6 +++++ lib/utimens.c | 26 +++++++++++++++++---- lib/utimens.h | 4 ++-- src/extract.c | 61 +++++++++++++++++++++++------------------------- src/misc.c | 2 +- 5 files changed, 59 insertions(+), 40 deletions(-) diff --git a/debian/changelog b/debian/changelog index 393a9e1..99ce9de 100644 --- a/debian/changelog +++ b/debian/changelog @@ -1,3 +1,9 @@ +tar (1.22-3) UNRELEASED; urgency=low + + * Preserve timestamps of extracted symlinks, closes: #313237 + + -- Carl Worth Tue, 04 Aug 2009 17:11:18 -0700 + tar (1.22-2) unstable; urgency=low * Add Carl Worth as an uploader. diff --git a/lib/utimens.c b/lib/utimens.c index 708de10..ae8b0a6 100644 --- a/lib/utimens.c +++ b/lib/utimens.c @@ -72,11 +72,16 @@ struct utimbuf use just futimes (or equivalent) instead of utimes (or equivalent), and fail if on an old system without futimes (or equivalent). If TIMESPEC is null, set the time stamps to the current time. + If the file is a symlink and IS_SYMLINK is set, then the + time stamps of the symlink itself will be updated if + possible, (but if not supported by the operating system + then no change will occur). Return 0 on success, -1 (setting errno) on failure. */ int gl_futimens (int fd ATTRIBUTE_UNUSED, - char const *file, struct timespec const timespec[2]) + char const *file, struct timespec const timespec[2], + int is_symlink) { /* Some Linux-based NFS clients are buggy, and mishandle time stamps of files in NFS file systems in some cases. We have no @@ -102,7 +107,8 @@ gl_futimens (int fd ATTRIBUTE_UNUSED, #if HAVE_UTIMENSAT if (fd < 0) { - int result = utimensat (AT_FDCWD, file, timespec, 0); + int flags = is_symlink ? AT_SYMLINK_NOFOLLOW : 0; + int result = utimensat (AT_FDCWD, file, timespec, flags); # ifdef __linux__ /* Work around what might be a kernel bug: http://bugzilla.redhat.com/442352 @@ -119,6 +125,12 @@ gl_futimens (int fd ATTRIBUTE_UNUSED, return result; } #endif + + /* Without utimensat we have no way to update a symlink rather than + * the target, so just return immediately. */ + if (is_symlink) + return 0; + #if HAVE_FUTIMENS { int result = futimens (fd, timespec); @@ -219,9 +231,13 @@ gl_futimens (int fd ATTRIBUTE_UNUSED, } /* Set the access and modification time stamps of FILE to be - TIMESPEC[0] and TIMESPEC[1], respectively. */ + TIMESPEC[0] and TIMESPEC[1], respectively. + If the file is a symlink and is_symlink is set, then the + time stamps of the symlink itself will be updated if + possible, (but if not supported by the operating system + then no change will occur). */ int -utimens (char const *file, struct timespec const timespec[2]) +utimens (char const *file, struct timespec const timespec[2], int is_symlink) { - return gl_futimens (-1, file, timespec); + return gl_futimens (-1, file, timespec, is_symlink); } diff --git a/lib/utimens.h b/lib/utimens.h index 169521d..625785c 100644 --- a/lib/utimens.h +++ b/lib/utimens.h @@ -1,3 +1,3 @@ #include -int gl_futimens (int, char const *, struct timespec const [2]); -int utimens (char const *, struct timespec const [2]); +int gl_futimens (int, char const *, struct timespec const [2], int flags); +int utimens (char const *, struct timespec const [2], int flags); diff --git a/src/extract.c b/src/extract.c index 6d70398..5ca192d 100644 --- a/src/extract.c +++ b/src/extract.c @@ -239,43 +239,40 @@ set_stat (char const *file_name, mode_t invert_permissions, enum permstatus permstatus, char typeflag) { - if (typeflag != SYMTYPE) + /* We do the utime before the chmod because some versions of utime are + broken and trash the modes of the file. */ + + if (! touch_option && permstatus != INTERDIR_PERMSTATUS) { - /* We do the utime before the chmod because some versions of utime are - broken and trash the modes of the file. */ + /* We set the accessed time to `now', which is really the time we + started extracting files, unless incremental_option is used, in + which case .st_atime is used. */ - if (! touch_option && permstatus != INTERDIR_PERMSTATUS) - { - /* We set the accessed time to `now', which is really the time we - started extracting files, unless incremental_option is used, in - which case .st_atime is used. */ - - /* FIXME: incremental_option should set ctime too, but how? */ - - struct timespec ts[2]; - if (incremental_option) - ts[0] = st->atime; - else - ts[0] = start_time; - ts[1] = st->mtime; - - if (utimens (file_name, ts) != 0) - utime_error (file_name); - else - { - check_time (file_name, ts[0]); - check_time (file_name, ts[1]); - } - } + /* FIXME: incremental_option should set ctime too, but how? */ - /* Some systems allow non-root users to give files away. Once this - done, it is not possible anymore to change file permissions. - However, setting file permissions now would be incorrect, since - they would apply to the wrong user, and there would be a race - condition. So, don't use systems that allow non-root users to - give files away. */ + struct timespec ts[2]; + if (incremental_option) + ts[0] = st->atime; + else + ts[0] = start_time; + ts[1] = st->mtime; + + if (utimens (file_name, ts, typeflag == SYMTYPE) != 0) + utime_error (file_name); + else + { + check_time (file_name, ts[0]); + check_time (file_name, ts[1]); + } } + /* Some systems allow non-root users to give files away. Once this + done, it is not possible anymore to change file permissions. + However, setting file permissions now would be incorrect, since + they would apply to the wrong user, and there would be a race + condition. So, don't use systems that allow non-root users to + give files away. */ + if (0 < same_owner_option && permstatus != INTERDIR_PERMSTATUS) { /* When lchown exists, it should be used to change the attributes of diff --git a/src/misc.c b/src/misc.c index 951449e..d8255f7 100644 --- a/src/misc.c +++ b/src/misc.c @@ -516,7 +516,7 @@ set_file_atime (int fd, char const *file, struct timespec const timespec[2]) } #endif - return gl_futimens (fd, file, timespec); + return gl_futimens (fd, file, timespec, 0); } /* A description of a working directory. */ -- 2.43.0