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Various fixes when creating objects on disk:

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* Write xattrs last instead of first (required on platforms that use
   system xattrs for security attributes)
 * Better handling of chdir() failures
 * Don't bother trying to shorten files via seek()/write()
 * Fix build on systems that lack link()/symlink()/mknod()
 * Prefer futimens()/utimensat() when they're present
This commit is contained in:
Tim Kientzle 2009-12-29 05:35:40 +00:00
parent dee0ce0cbd
commit bb8a41af51
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=201159
1 changed files with 74 additions and 23 deletions
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97
lib/libarchive/archive_write_disk.c
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@ -442,20 +442,23 @@ _archive_write_header(struct archive *_a, struct archive_entry *entry)
ret = restore_entry(a);
/*
* On the GNU tar mailing list, some people working with new
* Linux filesystems observed that system xattrs used as
* layout hints need to be restored before the file contents
* are written, so this can't be done at file close.
* TODO: There are rumours that some extended attributes must
* be restored before file data is written. If this is true,
* then we either need to write all extended attributes both
* before and after restoring the data, or find some rule for
* determining which must go first and which last. Due to the
* many ways people are using xattrs, this may prove to be an
* intractable problem.
*/
if (a->todo & TODO_XATTR) {
int r2 = set_xattrs(a);
if (r2 < ret) ret = r2;
}
#ifdef HAVE_FCHDIR
/* If we changed directory above, restore it here. */
if (a->restore_pwd >= 0) {
fchdir(a->restore_pwd);
r = fchdir(a->restore_pwd);
if (r != 0) {
archive_set_error(&a->archive, errno, "chdir() failure");
ret = ARCHIVE_FATAL;
}
close(a->restore_pwd);
a->restore_pwd = -1;
}
@ -692,15 +695,18 @@ _archive_write_finish_entry(struct archive *_a)
}
#endif
/*
* Explicitly stat the file as some platforms might not
* implement the XSI option to extend files via ftruncate.
* Not all platforms implement the XSI option to
* extend files via ftruncate. Stat() the file again
* to see what happened.
*/
a->pst = NULL;
if ((ret = _archive_write_disk_lazy_stat(a)) != ARCHIVE_OK)
return (ret);
if (a->st.st_size != a->filesize) {
/* We can use lseek()/write() to extend the file if
* ftruncate didn't work or isn't available. */
if (a->st.st_size < a->filesize) {
const char nul = '\0';
if (lseek(a->fd, a->st.st_size - 1, SEEK_SET) < 0) {
if (lseek(a->fd, a->filesize - 1, SEEK_SET) < 0) {
archive_set_error(&a->archive, errno,
"Seek failed");
return (ARCHIVE_FATAL);
@ -747,6 +753,17 @@ _archive_write_finish_entry(struct archive *_a)
int r2 = set_acls(a);
if (r2 < ret) ret = r2;
}
/*
* Security-related extended attributes (such as
* security.capability on Linux) have to be restored last,
* since they're implicitly removed by other file changes.
*/
if (a->todo & TODO_XATTR) {
int r2 = set_xattrs(a);
if (r2 < ret) ret = r2;
}
/*
* Some flags prevent file modification; they must be restored after
* file contents are written.
@ -1057,7 +1074,7 @@ restore_entry(struct archive_write_disk *a)
* the failed system call. Note: This function should only ever perform
* a single system call.
*/
int
static int
create_filesystem_object(struct archive_write_disk *a)
{
/* Create the entry. */
@ -1069,6 +1086,9 @@ create_filesystem_object(struct archive_write_disk *a)
/* Since link(2) and symlink(2) don't handle modes, we're done here. */
linkname = archive_entry_hardlink(a->entry);
if (linkname != NULL) {
#if !HAVE_LINK
return (EPERM);
#else
r = link(linkname, a->name) ? errno : 0;
/*
* New cpio and pax formats allow hardlink entries
@ -1091,10 +1111,16 @@ create_filesystem_object(struct archive_write_disk *a)
r = errno;
}
return (r);
#endif
}
linkname = archive_entry_symlink(a->entry);
if (linkname != NULL)
if (linkname != NULL) {
#if HAVE_SYMLINK
return symlink(linkname, a->name) ? errno : 0;
#else
return (EPERM);
#endif
}
/*
* The remaining system calls all set permissions, so let's
@ -1126,22 +1152,22 @@ create_filesystem_object(struct archive_write_disk *a)
* S_IFCHR for the mknod() call. This is correct. */
r = mknod(a->name, mode | S_IFCHR,
archive_entry_rdev(a->entry));
break;
#else
/* TODO: Find a better way to warn about our inability
* to restore a char device node. */
return (EINVAL);
#endif /* HAVE_MKNOD */
break;
case AE_IFBLK:
#ifdef HAVE_MKNOD
r = mknod(a->name, mode | S_IFBLK,
archive_entry_rdev(a->entry));
break;
#else
/* TODO: Find a better way to warn about our inability
* to restore a block device node. */
return (EINVAL);
#endif /* HAVE_MKNOD */
break;
case AE_IFDIR:
mode = (mode | MINIMUM_DIR_MODE) & MAXIMUM_DIR_MODE;
r = mkdir(a->name, mode);
@ -1161,12 +1187,12 @@ create_filesystem_object(struct archive_write_disk *a)
case AE_IFIFO:
#ifdef HAVE_MKFIFO
r = mkfifo(a->name, mode);
break;
#else
/* TODO: Find a better way to warn about our inability
* to restore a fifo. */
return (EINVAL);
#endif /* HAVE_MKFIFO */
break;
}
/* All the system calls above set errno on failure. */
@ -1394,9 +1420,15 @@ current_fixup(struct archive_write_disk *a, const char *pathname)
* scan the path and both can be optimized by comparing against other
* recent paths.
*/
/* TODO: Extend this to support symlinks on Windows Vista and later. */
static int
check_symlinks(struct archive_write_disk *a)
{
#if !defined(HAVE_LSTAT)
/* Platform doesn't have lstat, so we can't look for symlinks. */
(void)a; /* UNUSED */
return (ARCHIVE_OK);
#else
char *pn, *p;
char c;
int r;
@ -1477,6 +1509,7 @@ check_symlinks(struct archive_write_disk *a)
/* We've checked and/or cleaned the whole path, so remember it. */
archive_strcpy(&a->path_safe, a->name);
return (ARCHIVE_OK);
#endif
}
#if defined(_WIN32) || defined(__CYGWIN__)
@ -1661,8 +1694,6 @@ create_dir(struct archive_write_disk *a, char *path)
mode_t mode_final, mode;
int r;
r = ARCHIVE_OK;
/* Check for special names and just skip them. */
slash = strrchr(path, '/');
if (slash == NULL)
@ -1806,11 +1837,31 @@ set_ownership(struct archive_write_disk *a)
return (ARCHIVE_WARN);
}
#ifdef HAVE_UTIMES
#if defined(HAVE_UTIMENSAT) && defined(HAVE_FUTIMENS)
/*
* utimensat() and futimens() are defined in POSIX.1-2008. They provide ns
* resolution and setting times on fd and on symlinks, too.
*/
static int
set_time(int fd, int mode, const char *name,
time_t atime, long atime_nsec,
time_t mtime, long mtime_nsec)
{
struct timespec ts[2];
ts[0].tv_sec = atime;
ts[0].tv_nsec = atime_nsec;
ts[1].tv_sec = mtime;
ts[1].tv_nsec = mtime_nsec;
if (fd >= 0)
return futimens(fd, ts);
return utimensat(AT_FDCWD, name, ts, AT_SYMLINK_NOFOLLOW);
}
#elif HAVE_UTIMES
/*
* The utimes()-family functions provide high resolution and
* The utimes()-family functions provide µs-resolution and
* a way to set time on an fd or a symlink. We prefer them
* when they're available.
* when they're available and utimensat/futimens aren't there.
*/
static int
set_time(int fd, int mode, const char *name,