Messages in this thread | | | Date | Thu, 6 Dec 2001 21:01:59 +0100 (CET) | From | kees <> | Subject | Q: device(file) permissions for USB |
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Hi,
I have been playing with an USB camera. I've run into the following problem: The (default?) permissions for /proc/bus/usb/001/011 (and others) are 0644. This makes the ioctl (see attached trace to fail). So I have to: either chmod the usb device file each time I unplug and replug the camera OR make the pencam program SUID root, which is neither comfortable. Is there a way to affect the default permissions for the USB devices?
regards Kees open("/proc/bus/usb/002/001", O_RDONLY) = 5 read(5, "\22\1\0\1\t\0\0\10\0\0\0\0\0\0\0\2\1\1", 18) = 18 close(5) = 0 ipc_subcall(0x4, 0x804e568, 0x400, 0) = 0 close(4) = 0 open("/proc/bus/usb/001/011", O_RDWR) = -1 EACCES (Permission denied) open("/proc/bus/usb/001/011", O_RDONLY) = 4 ioctl(4, 0x80045505, 0xbfffeaf8) = -1 EPERM (Operation not permitted) fstat64(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 7), ...}) = 0 old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000 ioctl(1, TCGETS, {B9600 opost isig icanon echo ...}) = 0 write(1, "pencam_set_configuration error\n", 31) = 31 ioctl(4, 0xc0105500, 0xbfffeaac) = -1 EPERM (Operation not permitted) ioctl(4, 0xc0105500, 0xbfffeaac) = -1 EPERM (Operation not permitted) write(1, "Last error: 255, command = 0xff"..., 33) = 33 write(1, "Camera ping failed!! Check conne"..., 54) = 54 write(1, "Error initializing camera!!\n", 28) = 28 close(4) = 0
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