dasdfmt: Replace ERRMSG_EXIT macro with an error handling function
dasdfmt: Replace ERRMSG_EXIT macro with an error handling function

The ERRMSG_EXIT macro is a bit clunky in its usage and a change is
necessary in order to free memory in error cases.

Create a new function error() that takes only a format string and adds
all other relevant information by itself. This function frees memory
before terminating the program with the EXIT_FAILURE exit code.

This simplifies the error handling for pretty much all calls and makes
the code a bit cleaner.

While at it, the defines EXIT_MISUSE and EXIT_BUSY don't provide any
value. Neither are they documented nor are these standardized. Also, a
parent process is mostly interessted in success or failure only anyway.
Replace these by using only EXIT_FAILURE in the error() function.

Also, change multiline output to a combination of warnx and error to
have a uniformed output. So this:

WARNING: Device is formatted with a different blocksize (4096).
Use --mode=full to perform a clean format.

becomes this:

dasdfmt: WARNING: Device is formatted with a different blocksize (4096).
dasdfmt: Use --mode=full to perform a clean format.

Reviewed-by: Stefan Haberland <dec981e3bbb165d021029c42291faf06f59827c1@linux.ibm.com>
Signed-off-by: Jan Höppner <96138615ab4af0813785fa10d283f3d37eca3b78@linux.ibm.com>

ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools