using fork & execv in cgi scripts

Matthew Jones (matj@hchworth.demon.co.uk)
Wed, 12 Apr 1995 10:23:41 +0100 (BST)

Sorry if you get 2 copies of this message, I had an error when I sent
the first version.

---


Can anybody help?


I've run into another problem whilst developing cgi scripts.  This time
I want to develop a script that makes calls to fork and execv to spawn
another process.  The script works fine when run at the shell prompt
but won't work through httpd.  I've included the script at the end of
this message.  Here's what I get when running through httpd:


EXCEPTION


posix.error : (10, 'no children') 


Traceback (innermost last):
  File "/usr/local/etc/httpd/cgi-bin/update_users.py", line 66, in ?
    main()
  File "/usr/local/etc/httpd/cgi-bin/update_users.py", line 55, in main
    update_users()
  File "/usr/local/etc/httpd/cgi-bin/update_users.py", line 37, in update_users
    sys.exit(0)
SystemExit: 0




Do I need to do something differently to spawn processes when running a
cgi script?  


Thanks


mat.
matj@hchworth.demon.co.uk      


------------ cut here ----------------


#! /usr/local/bin/python
# update_users.py


from os import environ
import cgi, sys, string, regex


# Get WWW form variables
#wwwform = cgi.FormContent()
#dict = wwwform.pars()
dict = {'user_id':['newuser'],'passwd1':['passwd'],'passwd2':['passwd']}


def update_users():
	from posix import execv, fork, wait
	global dict


	try:
		fd_pub = open("/home/matj/podsys/data/publisher.key",'r')
	except IOError:
		sys.exit(-1)


	new_user_id = dict['user_id'][0]
	new_user_passwd = dict['passwd1'][0]
	args = ('ex_update_users.exp',new_user_id,new_user_passwd)


	try:
		parent = fork()
	except:
		#raise RunTimeError, 'fork failed'
		sys.exit(-1)


	if parent:
		try:
			wait()
		except:
			print "<H2>EXCEPTION</H2>"
			print sys.exc_type, ":", sys.exc_value
			sys.exit(0)
	else:
		try:
			execv('/usr/local/etc/httpd/cgi-bin/ex_update_users.exp', ['ex_update_users.exp', new_user_id, new_user_passwd])
		except:
			print "<H2>EXCEPTION</H2>"
			print sys.exc_type, ":", sys.exc_value
			sys.exit(0)
		


def main():
	print "Content-type: text/HTML\n"
	print "<HTML>"
	print "<HEAD>"
	print "</HEAD>"
	
	if dict.has_key('passwd1') and dict.has_key('passwd2'):
		if dict['passwd1'] == dict['passwd2']:
			update_users()
		else:
			print "<B>Error: passwords are not the same!</B>"
	else:
		print "<B>Error: both password fields must be filled in!</B>"


	print "</HTML>"


if __name__ == '__main__':     # Only do this when run as a script
	import sys, traceback      # Be prepared!
	try:
		main()
	except SystemError, sts:   # main() called sys.exit(sts)
		sys.exit(sts)
	except:
		print "\n<XMP>"        # Turn off HTML parsing
		traceback.print_exc()  # Print stack trace