ece373-hw/hw1/section_a.md

title, author

title	author
ECE 371 HW 1	Edith Boles

1. open() system call

   A. List the BUGS when using the system call.

   BUGS

   Currently, it is not possible to enable signal-driven I/O by specifying O_ASYNC when calling open(); use fcntl(2) to enable this flag.

   One must check for two different error codes, EISDIR and ENOENT, when trying to determine whether the kernel supports O_TMPFILE functionality.

   When both O_CREAT and O_DIRECTORY are specified in flags and the file specified by pathname does not exist, open() will create a regular file (i.e., O_DIRECTORY is ignored).

   B. What files need to be included to use this function?

   open is inside fcntl.h.

   C. List the first three related system calls to open().

   SEE ALSO
          chmod(2), chown(2), close(2), ...
   

   D. Choose one of the system calls from above and list its bugs (also list what system call you chose) and files needing to be included to use the system call

   For link(2), you need to include fcntrl.h and unistd.h. The BUGS section details an issue on NFS filesystems that requires verifying the operation before assuming it succeeded.

2. https://elixir.bootlin.com/, searching on kernel v6.19.11

   A. usb_device is defined in include/linux/usb.h, with first five members being:

   int		devnum;
   char		devpath[16];
   u32		route;
   enum usb_device_state	state;
   enum usb_device_speed	speed;
   

   B. include/uapi/linux/usb/ch9.h

   C. ``` enum usb_device_speed { USB_SPEED_UNKNOWN = 0, /* enumerating / USB_SPEED_LOW, USB_SPEED_FULL, / usb 1.1 / USB_SPEED_HIGH, / usb 2.0 / USB_SPEED_WIRELESS, / wireless (usb 2.5) / USB_SPEED_SUPER, / usb 3.0 / USB_SPEED_SUPER_PLUS, / usb 3.1 */ };