#include <sys/types.h>
#include <signal.h>
#include <stdbool.h>
+#include <stddef.h>
#include <sys/stat.h>
#include <errno.h>
#include "revision.h"
#include "timespec.h"
-#include "fcntl-safer.h"
+#include "dirname.h"
+#include "fcntl--.h"
#include "getopt.h"
#include "ignore-value.h"
#include "stat-time.h"
/* configuration */
-#include <fcntl.h>
#include <limits.h>
#include <unistd.h>
#include <stdlib.h>
# include <utimens.h>
#endif
-#define RW_USER (S_IRUSR | S_IWUSR) /* creation mode for open() */
-
#ifndef MAX_PATH_LEN
# define MAX_PATH_LEN 1024 /* max pathname length */
#endif
static off_t total_out; /* output bytes for all files */
char ifname[MAX_PATH_LEN]; /* input file name */
char ofname[MAX_PATH_LEN]; /* output file name */
+static char dfname[MAX_PATH_LEN]; /* name of dir containing output file */
static struct stat istat; /* status for input file */
int ifd; /* input file descriptor */
int ofd; /* output file descriptor */
+static int dfd = -1; /* output directory file descriptor */
unsigned insize; /* valid bytes in inbuf */
unsigned inptr; /* index of next byte to be processed in inbuf */
unsigned outcnt; /* bytes in output buffer */
}
}
+static char const dot = '.';
+
+/* True if the cached directory for calls to openat etc. is DIR, with
+ length DIRLEN. DIR need not be null-terminated. DIRLEN must be
+ less than MAX_PATH_LEN. */
+static bool
+atdir_eq (char const *dir, ptrdiff_t dirlen)
+{
+ if (dirlen == 0)
+ dir = &dot, dirlen = 1;
+ return memcmp (dfname, dir, dirlen) == 0 && !dfname[dirlen];
+}
+
+/* Set the directory used for calls to openat etc. to be the directory
+ DIR, with length DIRLEN. DIR need not be null-terminated.
+ DIRLEN must be less than MAX_PATH_LEN. Return a file descriptor for
+ the directory, or -1 if one could not be obtained. */
+static int
+atdir_set (char const *dir, ptrdiff_t dirlen)
+{
+ /* Don't bother opening directories on older systems that
+ lack openat and unlinkat. It's not worth the porting hassle. */
+ #if HAVE_OPENAT && HAVE_UNLINKAT
+ enum { try_opening_directories = true };
+ #else
+ enum { try_opening_directories = false };
+ #endif
+
+ if (try_opening_directories && ! atdir_eq (dir, dirlen))
+ {
+ if (0 <= dfd)
+ close (dfd);
+ if (dirlen == 0)
+ dir = &dot, dirlen = 1;
+ memcpy (dfname, dir, dirlen);
+ dfname[dirlen] = '\0';
+ dfd = open (dfname, O_SEARCH | O_DIRECTORY);
+ }
+
+ return dfd;
+}
+
/* ========================================================================
* Compress or decompress the given file
*/
{
copy_stat (&istat);
- /* Transfer output data to the output file's storage device.
+ /* If KEEP, transfer output data to the output file's storage device.
Otherwise, if the system crashed now the user might lose
both input and output data. See: Pillai TS et al. All
file systems are not created equal: on the complexity of
crafting crash-consistent applications. OSDI'14. 2014:433-48.
https://www.usenix.org/conference/osdi14/technical-sessions/presentation/pillai */
- if (!keep && fsync (ofd) != 0 && errno != EINVAL)
- write_error ();
-
- if (close (ofd) != 0)
+ if ((!keep
+ && ((0 <= dfd && fdatasync (dfd) != 0 && errno != EINVAL)
+ || (fsync (ofd) != 0 && errno != EINVAL)))
+ || close (ofd) != 0)
write_error ();
if (!keep)
{
sigset_t oldset;
int unlink_errno;
+ char *ifbase = last_component (ifname);
+ int ufd = atdir_eq (ifname, ifbase - ifname) ? dfd : -1;
+ int res;
sigprocmask (SIG_BLOCK, &caught_signals, &oldset);
remove_ofname_fd = -1;
- unlink_errno = xunlink (ifname) == 0 ? 0 : errno;
+ res = ufd < 0 ? xunlink (ifname) : unlinkat (ufd, ifbase, 0);
+ unlink_errno = res == 0 ? 0 : errno;
sigprocmask (SIG_SETMASK, &oldset, NULL);
if (unlink_errno)
int name_shortened = 0;
int flags = (O_WRONLY | O_CREAT | O_EXCL
| (ascii && decompress ? 0 : O_BINARY));
+ char const *base = ofname;
+ int atfd = AT_FDCWD;
+
+ if (!keep)
+ {
+ char const *b = last_component (ofname);
+ int f = atdir_set (ofname, b - ofname);
+ if (0 <= f)
+ {
+ base = b;
+ atfd = f;
+ }
+ }
for (;;)
{
sigset_t oldset;
sigprocmask (SIG_BLOCK, &caught_signals, &oldset);
- remove_ofname_fd = ofd = OPEN (ofname, flags, RW_USER);
+ remove_ofname_fd = ofd = openat (atfd, base, flags, S_IRUSR | S_IWUSR);
open_errno = errno;
sigprocmask (SIG_SETMASK, &oldset, NULL);
}
-/* Open file NAME with the given flags and mode and store its status
+/* Open file NAME with the given flags and store its status
into *ST. Return a file descriptor to the newly opened file, or -1
(setting errno) on failure. */
static int
-open_and_stat (char *name, int flags, mode_t mode, struct stat *st)
+open_and_stat (char *name, int flags, struct stat *st)
{
int fd;
+ int atfd = AT_FDCWD;
+ char const *base = name;
/* Refuse to follow symbolic links unless -c or -f. */
if (!to_stdout && !force)
}
}
- fd = OPEN (name, flags, mode);
+ if (!keep)
+ {
+ char const *b = last_component (name);
+ int f = atdir_set (name, b - name);
+ if (0 <= f)
+ {
+ base = b;
+ atfd = f;
+ }
+ }
+
+ fd = openat (atfd, base, flags);
if (0 <= fd && fstat (fd, st) != 0)
{
int e = errno;
strcpy(ifname, iname);
/* If input file exists, return OK. */
- fd = open_and_stat (ifname, open_flags, RW_USER, sbuf);
+ fd = open_and_stat (ifname, open_flags, sbuf);
if (0 <= fd)
return fd;
if (sizeof ifname <= ilen + strlen (s))
goto name_too_long;
strcat(ifname, s);
- fd = open_and_stat (ifname, open_flags, RW_USER, sbuf);
+ fd = open_and_stat (ifname, open_flags, sbuf);
if (0 <= fd)
return fd;
if (errno != ENOENT)
projects / debian / gzip / commitdiff