#5329: fix os.popen* regression from 2.5: don't execute commands as a sequence
through the shell. also document the correct subprocess replacement for this
case
patch from Jean-Paul Calderone and Jani Hakala
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 6b91f69..45e49a1 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -298,54 +298,80 @@
Replacing os.popen*
-------------------
-pipe = os.popen(cmd, mode='r', bufsize)
+pipe = os.popen("cmd", mode='r', bufsize)
==>
-pipe = Popen(cmd, shell=True, bufsize=bufsize, stdout=PIPE).stdout
+pipe = Popen("cmd", shell=True, bufsize=bufsize, stdout=PIPE).stdout
-pipe = os.popen(cmd, mode='w', bufsize)
+pipe = os.popen("cmd", mode='w', bufsize)
==>
-pipe = Popen(cmd, shell=True, bufsize=bufsize, stdin=PIPE).stdin
+pipe = Popen("cmd", shell=True, bufsize=bufsize, stdin=PIPE).stdin
-(child_stdin, child_stdout) = os.popen2(cmd, mode, bufsize)
+(child_stdin, child_stdout) = os.popen2("cmd", mode, bufsize)
==>
-p = Popen(cmd, shell=True, bufsize=bufsize,
+p = Popen("cmd", shell=True, bufsize=bufsize,
stdin=PIPE, stdout=PIPE, close_fds=True)
(child_stdin, child_stdout) = (p.stdin, p.stdout)
(child_stdin,
child_stdout,
- child_stderr) = os.popen3(cmd, mode, bufsize)
+ child_stderr) = os.popen3("cmd", mode, bufsize)
==>
-p = Popen(cmd, shell=True, bufsize=bufsize,
+p = Popen("cmd", shell=True, bufsize=bufsize,
stdin=PIPE, stdout=PIPE, stderr=PIPE, close_fds=True)
(child_stdin,
child_stdout,
child_stderr) = (p.stdin, p.stdout, p.stderr)
-(child_stdin, child_stdout_and_stderr) = os.popen4(cmd, mode, bufsize)
+(child_stdin, child_stdout_and_stderr) = os.popen4("cmd", mode,
+ bufsize)
==>
-p = Popen(cmd, shell=True, bufsize=bufsize,
+p = Popen("cmd", shell=True, bufsize=bufsize,
stdin=PIPE, stdout=PIPE, stderr=STDOUT, close_fds=True)
(child_stdin, child_stdout_and_stderr) = (p.stdin, p.stdout)
+On Unix, os.popen2, os.popen3 and os.popen4 also accept a sequence as
+the command to execute, in which case arguments will be passed
+directly to the program without shell intervention. This usage can be
+replaced as follows:
+
+(child_stdin, child_stdout) = os.popen2(["/bin/ls", "-l"], mode,
+ bufsize)
+==>
+p = Popen(["/bin/ls", "-l"], bufsize=bufsize, stdin=PIPE, stdout=PIPE)
+(child_stdin, child_stdout) = (p.stdin, p.stdout)
+
+Return code handling translates as follows:
+
+pipe = os.popen("cmd", 'w')
+...
+rc = pipe.close()
+if rc != None and rc % 256:
+ print "There were some errors"
+==>
+process = Popen("cmd", 'w', shell=True, stdin=PIPE)
+...
+process.stdin.close()
+if process.wait() != 0:
+ print "There were some errors"
+
Replacing popen2.*
------------------
-Note: If the cmd argument to popen2 functions is a string, the command
-is executed through /bin/sh. If it is a list, the command is directly
-executed.
-
(child_stdout, child_stdin) = popen2.popen2("somestring", bufsize, mode)
==>
p = Popen(["somestring"], shell=True, bufsize=bufsize
stdin=PIPE, stdout=PIPE, close_fds=True)
(child_stdout, child_stdin) = (p.stdout, p.stdin)
+On Unix, popen2 also accepts a sequence as the command to execute, in
+which case arguments will be passed directly to the program without
+shell intervention. This usage can be replaced as follows:
-(child_stdout, child_stdin) = popen2.popen2(["mycmd", "myarg"], bufsize, mode)
+(child_stdout, child_stdin) = popen2.popen2(["mycmd", "myarg"], bufsize,
+ mode)
==>
p = Popen(["mycmd", "myarg"], bufsize=bufsize,
stdin=PIPE, stdout=PIPE, close_fds=True)