#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/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index 09ae62b..10747e6 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -457,21 +457,21 @@
::
- pipe = os.popen(cmd, 'r', bufsize)
+ pipe = os.popen("cmd", '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, 'w', bufsize)
+ pipe = os.popen("cmd", '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)
@@ -479,9 +479,9 @@
(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,
@@ -489,21 +489,33 @@
::
- (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')
+ pipe = os.popen("cmd", 'w')
...
rc = pipe.close()
- if rc != None and rc % 256:
+ if rc != None and rc % 256:
print "There were some errors"
==>
- process = Popen(cmd, 'w', stdin=PIPE)
+ process = Popen("cmd", 'w', shell=True, stdin=PIPE)
...
process.stdin.close()
if process.wait() != 0:
@@ -513,11 +525,6 @@
Replacing functions from the :mod:`popen2` module
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-.. 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)
@@ -526,9 +533,12 @@
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)
diff --git a/Lib/os.py b/Lib/os.py
index 40d117e..c41af1a 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -666,8 +666,9 @@
import subprocess
PIPE = subprocess.PIPE
- p = subprocess.Popen(cmd, shell=True, bufsize=bufsize,
- stdin=PIPE, stdout=PIPE, close_fds=True)
+ p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring),
+ bufsize=bufsize, stdin=PIPE, stdout=PIPE,
+ close_fds=True)
return p.stdin, p.stdout
__all__.append("popen2")
@@ -685,9 +686,9 @@
import subprocess
PIPE = subprocess.PIPE
- p = subprocess.Popen(cmd, shell=True, bufsize=bufsize,
- stdin=PIPE, stdout=PIPE, stderr=PIPE,
- close_fds=True)
+ p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring),
+ bufsize=bufsize, stdin=PIPE, stdout=PIPE,
+ stderr=PIPE, close_fds=True)
return p.stdin, p.stdout, p.stderr
__all__.append("popen3")
@@ -705,8 +706,8 @@
import subprocess
PIPE = subprocess.PIPE
- p = subprocess.Popen(cmd, shell=True, bufsize=bufsize,
- stdin=PIPE, stdout=PIPE,
+ p = subprocess.Popen(cmd, shell=isinstance(cmd, basestring),
+ bufsize=bufsize, stdin=PIPE, stdout=PIPE,
stderr=subprocess.STDOUT, close_fds=True)
return p.stdin, p.stdout
__all__.append("popen4")
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)
diff --git a/Lib/test/test_popen2.py b/Lib/test/test_popen2.py
index 743b873..1383c62 100644
--- a/Lib/test/test_popen2.py
+++ b/Lib/test/test_popen2.py
@@ -78,6 +78,14 @@
def test_os_popen2(self):
# same test as test_popen2(), but using the os.popen*() API
+ if os.name == 'posix':
+ w, r = os.popen2([self.cmd])
+ self.validate_output(self.teststr, self.expected, r, w)
+
+ w, r = os.popen2(["echo", self.teststr])
+ got = r.read()
+ self.assertEquals(got, self.teststr + "\n")
+
w, r = os.popen2(self.cmd)
self.validate_output(self.teststr, self.expected, r, w)
@@ -87,9 +95,27 @@
w, r, e = os.popen3([self.cmd])
self.validate_output(self.teststr, self.expected, r, w, e)
+ w, r, e = os.popen3(["echo", self.teststr])
+ got = r.read()
+ self.assertEquals(got, self.teststr + "\n")
+ got = e.read()
+ self.assertFalse(got, "unexpected %r on stderr" % got)
+
w, r, e = os.popen3(self.cmd)
self.validate_output(self.teststr, self.expected, r, w, e)
+ def test_os_popen4(self):
+ if os.name == 'posix':
+ w, r = os.popen4([self.cmd])
+ self.validate_output(self.teststr, self.expected, r, w)
+
+ w, r = os.popen4(["echo", self.teststr])
+ got = r.read()
+ self.assertEquals(got, self.teststr + "\n")
+
+ w, r = os.popen4(self.cmd)
+ self.validate_output(self.teststr, self.expected, r, w)
+
def test_main():
run_unittest(Popen2Test)
diff --git a/Misc/NEWS b/Misc/NEWS
index 9cd6638..13912e9 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
Core and Builtins
-----------------
+- Issue #5329: Fix os.popen* regression from 2.5 with commands as a
+ sequence running through the shell. Patch by Jean-Paul Calderone
+ and Jani Hakala.
+
- Issue #7019: Raise ValueError when unmarshalling bad long data, instead
of producing internally inconsistent Python longs.