Commit 9e97fee0 authored Oct 17, 2013 by Scott Anderson

Enhance the ioctl toolbox command



1) Implement documented but unimplemented read-only option.
2) Allow standard input to be used as the <device> by passing
   "-".  On some devices, opening the device has side effects.
   Allowing standard input can prevent this by using a sequence
   of something like:

      # Open the device on file descriptor 3
      exec 3<> /dev/something
      ioctl -d - 0 0 <&3
      ioctl -d - 1 0 <&3
      dd if=myfile >&3
      # Close file descriptor 3
      exec 3>&-

Change-Id: If17ac3cffa7ccb159051550724b4ce7d8efa5feb
Signed-off-by: Scott Anderson <saa@android.com>

parent 8ac7c9f6

toolbox/ioctl.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -63,11 +63,15 @@ int ioctl_main(int argc, char *argv[])
		exit(1);
		}

		fd = open(argv[optind], O_RDWR \| O_SYNC);
		if (!strcmp(argv[optind], "-")) {
		fd = STDIN_FILENO;
		} else {
		fd = open(argv[optind], read_only ? O_RDONLY : (O_RDWR \| O_SYNC));
		if (fd < 0) {
		fprintf(stderr, "cannot open %s\n", argv[optind]);
		return 1;
		}
		}
		optind++;

		ioctl_nr = strtol(argv[optind], NULL, 0);