From 851d97cf07ce846079e02c800daa54bab8314c2a Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@gentoo.org>
Date: Thu, 17 May 2007 09:13:00 +0000
Subject: [PATCH] For bug #162404, use a pseudo-terminal device pair (instead
 of a normal pipe) for moving ouput out of the sesandbox domain.

svn path=/main/trunk/; revision=6541
---
 pym/portage/__init__.py | 72 +++++++++++++++++++++++++++--------------
 1 file changed, 47 insertions(+), 25 deletions(-)

diff --git a/pym/portage/__init__.py b/pym/portage/__init__.py
index cf27256aa..acb403b80 100644
--- a/pym/portage/__init__.py
+++ b/pym/portage/__init__.py
@@ -2258,10 +2258,12 @@ def spawn(mystring, mysettings, debug=0, free=0, droppriv=0, sesandbox=0, **keyw
 	# from shells and from binaries that belong to portage (the number of entry
 	# points is minimized).  The "tee" binary is not among the allowed entry
 	# points, so it is spawned outside of the sesandbox domain and reads from a
-	# pipe between two domains.
+	# pseudo-terminal that connects two domains.
 	logfile = keywords.get("logfile")
 	mypids = []
-	pw = None
+	slave_fd = None
+	output_pid = None
+	input_pid = None
 	if logfile:
 		del keywords["logfile"]
 		fd_pipes = keywords.get("fd_pipes")
@@ -2269,12 +2271,29 @@ def spawn(mystring, mysettings, debug=0, free=0, droppriv=0, sesandbox=0, **keyw
 			fd_pipes = {0:0, 1:1, 2:2}
 		elif 1 not in fd_pipes or 2 not in fd_pipes:
 			raise ValueError(fd_pipes)
-		pr, pw = os.pipe()
-		mypids.extend(portage.process.spawn(('tee', '-i', '-a', logfile),
-			 returnpid=True, fd_pipes={0:pr, 1:fd_pipes[1], 2:fd_pipes[2]}))
-		os.close(pr)
-		fd_pipes[1] = pw
-		fd_pipes[2] = pw
+		from pty import openpty
+		master_fd, slave_fd = openpty()
+		# Disable the ECHO attribute so the terminal behaves properly
+		# if the subprocess needs to read input from stdin.
+		import termios
+		term_attr = termios.tcgetattr(master_fd)
+		term_attr[3] &= ~termios.ECHO
+		termios.tcsetattr(master_fd, termios.TCSAFLUSH, term_attr)
+		# tee will always exit with an IO error, so ignore it's stderr.
+		null_file = open('/dev/null', 'w')
+		mypids.extend(portage.process.spawn(['tee', '-i', '-a', logfile],
+			returnpid=True, fd_pipes={0:master_fd, 1:fd_pipes[1],
+			2:null_file.fileno()}))
+		output_pid = mypids[-1]
+		mypids.extend(portage.process.spawn(['cat'],
+			returnpid=True, fd_pipes={0:fd_pipes[0], 1:master_fd,
+			2:null_file.fileno()}))
+		input_pid = mypids[-1]
+		os.close(master_fd)
+		null_file.close()
+		fd_pipes[0] = slave_fd
+		fd_pipes[1] = slave_fd
+		fd_pipes[2] = slave_fd
 		keywords["fd_pipes"] = fd_pipes
 
 	features = mysettings.features
@@ -2307,29 +2326,32 @@ def spawn(mystring, mysettings, debug=0, free=0, droppriv=0, sesandbox=0, **keyw
 	try:
 		mypids.extend(spawn_func(mystring, env=env, **keywords))
 	finally:
-		if pw:
-			os.close(pw)
+		if slave_fd:
+			os.close(slave_fd)
 		if sesandbox:
 			selinux.setexec(None)
 
 	if returnpid:
 		return mypids
 
-	while mypids:
-		pid = mypids.pop(0)
-		retval = os.waitpid(pid, 0)[1]
-		portage.process.spawned_pids.remove(pid)
-		if retval != os.EX_OK:
-			for pid in mypids:
-				if os.waitpid(pid, os.WNOHANG) == (0,0):
-					import signal
-					os.kill(pid, signal.SIGTERM)
-					os.waitpid(pid, 0)
-				portage.process.spawned_pids.remove(pid)
-			if retval & 0xff:
-				return (retval & 0xff) << 8
-			return retval >> 8
-	return os.EX_OK
+	if output_pid:
+		# tee will exit when the other end of the pseudo-terminal is closed.
+		os.waitpid(output_pid, 0)
+		portage.process.spawned_pids.remove(output_pid)
+	if input_pid:
+		# cat is blocking on stdin, so it must be killed.
+		import signal
+		os.kill(input_pid, signal.SIGTERM)
+		os.waitpid(input_pid, 0)
+		portage.process.spawned_pids.remove(input_pid)
+	pid = mypids[-1]
+	retval = os.waitpid(pid, 0)[1]
+	portage.process.spawned_pids.remove(pid)
+	if retval != os.EX_OK:
+		if retval & 0xff:
+			return (retval & 0xff) << 8
+		return retval >> 8
+	return retval
 
 def fetch(myuris, mysettings, listonly=0, fetchonly=0, locks_in_subdir=".locks",use_locks=1, try_mirrors=1):
 	"fetch files.  Will use digest file if available."
-- 
2.26.2