open and close error handling works, finally

diff --git a/virt-chroot/adt-virt-chroot b/virt-chroot/adt-virt-chroot
index b00f6d0a91c6cda427a968124c09e2f45a116e42..82f256076e91775afc7d42db7f91afe0f5fb9deb 100755 (executable)
--- a/virt-chroot/adt-virt-chroot
+++ b/virt-chroot/adt-virt-chroot
@@ -12,16 +12,16 @@ import string
 import urllib
 import signal
 import subprocess
+import traceback
 from optparse import OptionParser
 
 debuglevel = None
 
-class Quit(ecode):
-       def __init__(q,ec): q.ec = ec;
+class Quit:
+       def __init__(q,ec,m): q.ec = ec; q.m = m
 
 def bomb(m):
-       print >> sys.stderr "adt-virtual-chroot: failure:", m
-       raise Quit(16)
+       raise Quit(12, "adt-virtual-chroot: failure: %s" % m)
 
 def debug(m):
        if not debuglevel: return
@@ -46,7 +46,8 @@ def parse_args():
        chroot_arg = args[0]
        if not chroot_arg: pe("chroot specification may not be empty")
        if chroot_arg == '=': down = ['dchroot','-q']
-       elif chroot_arg[0] == '=': down = ['dchroot','-q','-d'+chroot_arg[1:]]
+       elif chroot_arg == '=': down = ['dchroot','-q']
+       elif chroot_arg[0] == '=': down = ['dchroot','-q','-c',chroot_arg[1:]]
        elif chroot_arg[0] == '/': down = ['chroot',chroot_arg,'--']
        else: pe("chroot spec must be =[DCHROOT] or /PATH/TO/CHROOT")
 
@@ -58,34 +59,62 @@ def ok(): print 'ok'
 
 def cmdnoargs(c, cu):
        if len(c) == 1: return
-       bomb("too many arguments to command `%s'": cu[0])
+       bomb("too many arguments to command `%s'" % cu[0])
 
 def cmd_capabilities(c, cu):
        cmdnoargs(c, cu)
 
 def cmd_quit(c, cu):
        cmdnoargs(c, cu)
-       raise Quit(0)
+       raise Quit(0, '')
+
+def execute(cmd_string, cmd_list=[], downp=False, outp=True):
+       cmdl = cmd_string.split()
+
+       if downp: perhaps_down = down
+       else: downp = []
+
+       if outp: stdout = subprocess.PIPE
+       else: stdout = None
+
+       cmd = down + cmdl + cmd_list
+       debug(" + %s" % string.join(cmd))
+
+       sp = subprocess.Popen(cmd, stdin=file('/dev/null','r'), stdout=stdout)
+       (out, err) = sp.communicate()
+       status = sp.wait()
+
+       if status: bomb("%s%s failed (exit status %d)" %
+                       ((downp and "(down) " or ""), cmdl[0], status))
+       if err: bomb("%s unexpectedly produced stderr output which we"
+                       "unexpectedly saw `%s'" % (cmdl[0], err))
+
+       if outp and out and out[-1]=='\n': out = out[:-1]
+
+       return out
 
 def cmd_open(c, cu):
+       global downtmp
        cmdnoargs(c, cu)
        if downtmp: bomb("`open' when already open")
-       (dt, err) =
-               subpocess.Popen(args = down + 'mktemp -t -d'.split(),
-                               stdin=PIPE, stdout=PIPE)
-                               .communicate()
-       if err: bomb("down mktemp failed: %s" % err)
-       downtmp = dt.rstrip("\n")
+       execute('true', downp=True, outp=False)
+       downtmp = execute('mktemp -t -d', downp=True)
+
+def cmd_close(c, cu):
+       global downtmp
+       cmdnoargs(c, cu)
+       if not downtmp: bomb("`close' when not open")
+       cleanup()
 
 def command():
        cu = sys.stdin.readline()
-       cu = c.rstrip().split()
+       cu = cu.rstrip().split()
        c = map(urllib.unquote, cu)
        if not c: bomb('empty commands are not permitted')
        try: f = globals()['cmd_'+c[0]]
        except ValueError: bomb("unknown command `%s'" % cu[0])
        r = f(c, cu)
-       if not r: r = ()
+       if not r: r = []
        r.insert(0, 'ok')
        ru = map(urllib.quote, r)
        print string.join(ru)
@@ -93,13 +122,27 @@ def command():
 def cleanup():
        global downtmp, cleaning
        cleaning = True
-       if downtmp:
-               (x, err) = subprocess.Popen(args = down
-                               + 'rm -rf --'.split() + [downtmp],
-                               stdin=PIPE, stdout=PIPE)
-                               .communicate()
-               if err: bomb("down rm -rf downtmp failed: %s" % err)
+       if downtmp: execute('rm -rf --', [downtmp], downp=True, outp=False)
        cleaning = False
+       downtmp = False
+
+def error_cleanup():
+       try:
+               ok = False
+               try:
+                       cleanup()
+                       ok = True
+               except Quit, q:
+                       print >> sys.stderr, q.m
+               except:
+                       print >> sys.stderr, "Unexpected cleanup error:"
+                       traceback.print_exc()
+                       print >> sys.stderr, ''
+               if not ok:
+                       print >> sys.stderr, ("while cleaning up"
+                               " because of another error:")
+       except:
+               pass
 
 def prepare():
        global downtmp, cleaning
@@ -107,7 +150,7 @@ def prepare():
        signal_list = [ signal.SIGHUP, signal.SIGTERM,
                        signal.SIGINT, signal.SIGPIPE ]
        def sethandlers(f):
-               for signum in signal_list: signal(signum, f)
+               for signum in signal_list: signal.signal(signum, f)
        def handler(args):
                sethandlers(signal.SIG_DFL)
                cleanup()
@@ -120,8 +163,11 @@ prepare()
 try:
        while True: command()
 except Quit, q:
-       cleanup()
-       exit(q.ec)
+       error_cleanup()
+       if q.m: print >> sys.stderr, q.m
+       sys.exit(q.ec)
 except:
-       cleanup()
-       raise
+       error_cleanup()
+       print >> sys.stderr, "Unexpected error:"
+       traceback.print_exc()
+       sys.exit(16)