Additional debug message

[w32zhong]

Print additional debug message to stderr when execution of script failed.

[w32zhong]

I spent a lot of time figuring out why my script cannot be executed (502 Gateway error), it turns out that my Bash script is missing Shebang line. It would be great if a debug message can be printed out so that I do not need to hack the code to find out why.

[Lekensteyn]

What about being more verbose than just "Error"? "Failed to execute script" or something like:

fprintf(stderr, "Failed to execute %s: %s\n", filename, strerror(errno));

[w32zhong]

I am not against removing the "Error", but cgi_error() function will also output "Cannot execute script ....", then it is kind of redundant to print "Failed to execute", but printing only the strerror(errno) without "Error" makes it a little confusing. Any idea on this?
@Lekensteyn

[Lekensteyn]

I suggest to add a parameter to cgi_error that can be used to append additional information that should only be logged to the error log (instead of stdout). This can then be NULL for everything except the internal server error. What do you think of that?

[w32zhong]

I would prefer to keep consistent to the current definition of cgi_error, because adding additional argument will make all the cgi_error calling filled with a NULL expect the "Cannot execute script" one. Create log functionality for only one possible error is not useful too. What I am thinking is just make a string containing the strerror message and pass it into filename argument. Actually I should say, cgi_error is not a very nice design, although it looks simple, but it assume every variable string should append in the end, which is not the case.