libbb: add xfstat function

function                                             old     new   delta
xfstat                                                 -      25     +25
mkfs_ext2_main                                      2421    2423      +2
mkfs_reiser_main                                    1197    1194      -3
next                                                 312     307      -5
ar_main                                              533     522     -11
mkfs_minix_main                                     2938    2924     -14
mkfs_vfat_main                                      1511    1495     -16
writeTarFile                                         272     255     -17
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/6 up/down: 27/-66)            Total: -39 bytes

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

archival/ar.c

@@ -123,8 +123,7 @@ static int write_ar_archive(archive_handle_t *handle)
 	struct stat st;
 	archive_handle_t *out_handle;
 
-	if (fstat(handle->src_fd, &st) == -1)
-		bb_simple_perror_msg_and_die(handle->ar__name);
+	xfstat(handle->src_fd, &st, handle->ar__name);
 
 	/* if archive exists, create a new handle for output.
 	 * we create it in place of the old one.

archival/tar.c

@@ -572,8 +572,7 @@ static NOINLINE int writeTarFile(int tar_fd, int verboseFlag,
 
 	/* Store the stat info for the tarball's file, so
 	 * can avoid including the tarball into itself....  */
-	if (fstat(tbInfo.tarFd, &tbInfo.tarFileStatBuf) < 0)
-		bb_perror_msg_and_die("can't stat tar file");
+	xfstat(tbInfo.tarFd, &tbInfo.tarFileStatBuf, "can't stat tar file");
 
 #if ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
 	if (gzip)

include/libbb.h

@@ -411,6 +411,7 @@ void bb_unsetenv(const char *key) FAST_FUNC;
 void bb_unsetenv_and_free(char *key) FAST_FUNC;
 void xunlink(const char *pathname) FAST_FUNC;
 void xstat(const char *pathname, struct stat *buf) FAST_FUNC;
+void xfstat(int fd, struct stat *buf, const char *errmsg) FAST_FUNC;
 int xopen(const char *pathname, int flags) FAST_FUNC;
 int xopen_nonblocking(const char *pathname) FAST_FUNC;
 int xopen3(const char *pathname, int flags, int mode) FAST_FUNC;

libbb/dump.c

@@ -323,9 +323,7 @@ static void do_skip(priv_dumper_t *dumper, const char *fname, int statok)
 	struct stat sbuf;
 
 	if (statok) {
-		if (fstat(STDIN_FILENO, &sbuf)) {
-			bb_simple_perror_msg_and_die(fname);
-		}
+		xfstat(STDIN_FILENO, &sbuf, fname);
 		if (!(S_ISCHR(sbuf.st_mode) || S_ISBLK(sbuf.st_mode) || S_ISFIFO(sbuf.st_mode))
 		 && dumper->pub.dump_skip >= sbuf.st_size
 		) {

libbb/update_passwd.c

@@ -133,7 +133,7 @@ int FAST_FUNC update_passwd(const char *filename,
 	goto close_old_fp;
 
  created:
-	if (!fstat(old_fd, &sb)) {
+	if (fstat(old_fd, &sb) == 0) {
 		fchmod(new_fd, sb.st_mode & 0777); /* ignore errors */
 		fchown(new_fd, sb.st_uid, sb.st_gid);
 	}

libbb/xfuncs_printf.c

@@ -436,6 +436,16 @@ void FAST_FUNC xstat(const char *name, struct stat *stat_buf)
 		bb_perror_msg_and_die("can't stat '%s'", name);
 }
 
+void FAST_FUNC xfstat(int fd, struct stat *stat_buf, const char *errmsg)
+{
+	/* errmsg is usually a file name, but not always:
+	 * xfstat may be called in a spot where file name is no longer
+	 * available, and caller may give e.g. "can't stat input file" string.
+	 */
+	if (fstat(fd, stat_buf))
+		bb_simple_perror_msg_and_die(errmsg);
+}
+
 // selinux_or_die() - die if SELinux is disabled.
 void FAST_FUNC selinux_or_die(void)
 {

miscutils/ubi_attach_detach.c

@@ -63,9 +63,9 @@ int ubi_attach_detach_main(int argc UNUSED_PARAM, char **argv)
 	ubi_ctrl = argv[optind];
 
 	fd = xopen(ubi_ctrl, O_RDWR);
-	//fstat(fd, &st);
+	//xfstat(fd, &st, ubi_ctrl);
 	//if (!S_ISCHR(st.st_mode))
-	//	bb_error_msg_and_die("'%s' is not a char device", ubi_ctrl);
+	//	bb_error_msg_and_die("%s: not a char device", ubi_ctrl);
 
 	if (do_attach) {
 		if (!(opts & OPTION_M))

shell/ash.c

@@ -4989,9 +4989,13 @@ noclobberopen(const char *fname)
 	 * revealed that it was a regular file, and the file has not been
 	 * replaced, return the file descriptor.
 	 */
-	if (fstat(fd, &finfo2) == 0 && !S_ISREG(finfo2.st_mode)
-	 && finfo.st_dev == finfo2.st_dev && finfo.st_ino == finfo2.st_ino)
+	if (fstat(fd, &finfo2) == 0
+	 && !S_ISREG(finfo2.st_mode)
+	 && finfo.st_dev == finfo2.st_dev
+	 && finfo.st_ino == finfo2.st_ino
+	) {
 		return fd;
+	}
 
 	/* The file has been replaced.  badness. */
 	close(fd);

util-linux/mkfs_ext2.c

@@ -221,7 +221,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
 
 	// open the device, check the device is a block device
 	xmove_fd(xopen(argv[0], O_WRONLY), fd);
-	fstat(fd, &st);
+	xfstat(fd, &st, argv[0]);
 	if (!S_ISBLK(st.st_mode) && !(option_mask32 & OPT_F))
 		bb_error_msg_and_die("%s: not a block device", argv[0]);
 

util-linux/mkfs_minix.c

@@ -686,8 +686,7 @@ int mkfs_minix_main(int argc UNUSED_PARAM, char **argv)
 		bb_error_msg_and_die("can't format mounted filesystem");
 
 	xmove_fd(xopen(G.device_name, O_RDWR), dev_fd);
-	if (fstat(dev_fd, &statbuf) < 0)
-		bb_error_msg_and_die("can't stat '%s'", G.device_name);
+	xfstat(dev_fd, &statbuf, G.device_name);
 	if (!S_ISBLK(statbuf.st_mode))
 		opt &= ~1; // clear -c (check)
 

util-linux/mkfs_reiser.c

@@ -168,9 +168,9 @@ int mkfs_reiser_main(int argc UNUSED_PARAM, char **argv)
 
 	// check the device is a block device
 	fd = xopen(argv[0], O_WRONLY | O_EXCL);
-	fstat(fd, &st);
+	xfstat(fd, &st, argv[0]);
 	if (!S_ISBLK(st.st_mode) && !(option_mask32 & OPT_f))
-		bb_error_msg_and_die("not a block device");
+		bb_error_msg_and_die("%s: not a block device", argv[0]);
 
 	// check if it is mounted
 	// N.B. what if we format a file? find_mount_point will return false negative since

util-linux/mkfs_vfat.c

@@ -245,8 +245,7 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 	volume_id = time(NULL);
 
 	dev = xopen(device_name, O_RDWR);
-	if (fstat(dev, &st) < 0)
-		bb_simple_perror_msg_and_die(device_name);
+	xfstat(dev, &st, device_name);
 
 	//
 	// Get image size and sector size

util-linux/mkswap.c

@@ -15,8 +15,7 @@ static void mkswap_selinux_setcontext(int fd, const char *path)
 	if (!is_selinux_enabled())
 		return;
 
-	if (fstat(fd, &stbuf) < 0)
-		bb_perror_msg_and_die("fstat failed");
+	xfstat(fd, &stbuf, argv[0]);
 	if (S_ISREG(stbuf.st_mode)) {
 		security_context_t newcon;
 		security_context_t oldcon = NULL;