[PATCH] Initialize struct stat st_[acm]tim.tv_nsec when present
Andrey Gursky
andrey.gursky at e-mail.ua
Tue Apr 18 23:59:24 UTC 2017
struct stat in libc for Linux kernel contains few fields more since 14+
years [1].
from bits/stat.h:
struct timespec st_atim; /* Time of last access. */
struct timespec st_mtim; /* Time of last modification. */
struct timespec st_ctim; /* Time of last status change. */
# define st_atime st_atim.tv_sec /* Backward compatibility. */
# define st_mtime st_mtim.tv_sec
# define st_ctime st_ctim.tv_sec
The conventional fields became an alias.
POSIX.1-2008 made struct stat st_[acm]tim mandatory [2].
OS takes care to initialize struct stat properly [3]. By not using an
OS syscall or a libc wrapper to fill struct stat, we have to take care
of initializing all fields (or at least those being used later) explicitly.
[1] https://www.sourceware.org/ml/libc-alpha/2002-12/msg00011.html
[2] https://www.sourceware.org/ml/libc-alpha/2009-11/msg00102.html
[3] https://www.sourceware.org/ml/libc-alpha/2002-12/msg00013.html
Fixes: file timestamps not preserved (https://mail.gnome.org/archives/mc-devel/2017-April/msg00000.html)
Reported-By: Nerijus Baliunas <nerijus at users.sourceforge.net>
---
configure.ac | 2 +-
src/vfs/cpio/cpio.c | 15 +++++++++++++++
src/vfs/tar/tar.c | 3 +++
3 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/configure.ac b/configure.ac
index 45836fcaf..387110daf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -181,7 +181,7 @@ AC_TYPE_PID_T
AC_TYPE_UID_T
AC_STRUCT_ST_BLOCKS
-AC_CHECK_MEMBERS([struct stat.st_blksize, struct stat.st_rdev])
+AC_CHECK_MEMBERS([struct stat.st_blksize, struct stat.st_rdev, struct stat.st_mtim])
gl_STAT_SIZE
AH_TEMPLATE([sig_atomic_t],
diff --git a/src/vfs/cpio/cpio.c b/src/vfs/cpio/cpio.c
index dba1a07c3..ffe6267cf 100644
--- a/src/vfs/cpio/cpio.c
+++ b/src/vfs/cpio/cpio.c
@@ -462,9 +462,15 @@ cpio_create_entry (struct vfs_class *me, struct vfs_s_super *super, struct stat
entry->ino->st.st_mode = st->st_mode;
entry->ino->st.st_uid = st->st_uid;
entry->ino->st.st_gid = st->st_gid;
+#ifdef HAVE_STRUCT_STAT_ST_MTIM
+ entry->ino->st.st_atim = st->st_atim;
+ entry->ino->st.st_mtim = st->st_mtim;
+ entry->ino->st.st_ctim = st->st_ctim;
+#else
entry->ino->st.st_atime = st->st_atime;
entry->ino->st.st_mtime = st->st_mtime;
entry->ino->st.st_ctime = st->st_ctime;
+#endif
}
g_free (name);
@@ -589,6 +595,9 @@ cpio_read_bin_head (struct vfs_class *me, struct vfs_s_super *super)
st.st_rdev = u.buf.c_rdev;
#endif
st.st_size = (u.buf.c_filesizes[0] << 16) | u.buf.c_filesizes[1];
+#ifdef HAVE_STRUCT_STAT_ST_MTIM
+ st.st_atim.tv_nsec = st.st_mtim.tv_nsec = st.st_ctim.tv_nsec = 0;
+#endif
st.st_atime = st.st_mtime = st.st_ctime = (u.buf.c_mtimes[0] << 16) | u.buf.c_mtimes[1];
return cpio_create_entry (me, super, &st, name);
@@ -658,6 +667,9 @@ cpio_read_oldc_head (struct vfs_class *me, struct vfs_s_super *super)
u.st.st_rdev = hd.c_rdev;
#endif
u.st.st_size = hd.c_filesize;
+#ifdef HAVE_STRUCT_STAT_ST_MTIM
+ u.st.st_atim.tv_nsec = u.st.st_mtim.tv_nsec = u.st.st_ctim.tv_nsec = 0;
+#endif
u.st.st_atime = u.st.st_mtime = u.st.st_ctime = hd.c_mtime;
return cpio_create_entry (me, super, &u.st, name);
@@ -736,6 +748,9 @@ cpio_read_crc_head (struct vfs_class *me, struct vfs_s_super *super)
u.st.st_rdev = makedev (hd.c_rdev, hd.c_rdevmin);
#endif
u.st.st_size = hd.c_filesize;
+#ifdef HAVE_STRUCT_STAT_ST_MTIM
+ u.st.st_atim.tv_nsec = u.st.st_mtim.tv_nsec = u.st.st_ctim.tv_nsec = 0;
+#endif
u.st.st_atime = u.st.st_mtime = u.st.st_ctime = hd.c_mtime;
return cpio_create_entry (me, super, &u.st, name);
diff --git a/src/vfs/tar/tar.c b/src/vfs/tar/tar.c
index 3afd8d68d..4b674739d 100644
--- a/src/vfs/tar/tar.c
+++ b/src/vfs/tar/tar.c
@@ -442,6 +442,9 @@ tar_fill_stat (struct vfs_s_super *archive, struct stat *st, union record *heade
}
st->st_size = h_size;
+#ifdef HAVE_STRUCT_STAT_ST_MTIM
+ st->st_atim.tv_nsec = st->st_mtim.tv_nsec = st->st_ctim.tv_nsec = 0;
+#endif
st->st_mtime = tar_from_oct (1 + 12, header->header.mtime);
st->st_atime = 0;
st->st_ctime = 0;
--
2.12.2+git20170411
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