From a3c2dcc3726261d6463ea35102d86863d698021b Mon Sep 17 00:00:00 2001

From: Tony Asleson <tasleson@redhat.com>

Date: Mon, 6 Jun 2022 09:56:32 -0500

Subject: [PATCH 9/9] lvmdbusd: Don't require "lvm> " prompt for shell

Depending on how lvm is compiled, it may not present the "lvm> " prompt

when using the lvm shell.  Don't require it to be present.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=2090391

(cherry picked from commit 691494268502ddb20da2a14568984c0fa4f29f50)

---

 daemons/lvmdbusd/lvm_shell_proxy.py.in | 83 +++++++++++++-------------

 1 file changed, 43 insertions(+), 40 deletions(-)

diff --git a/daemons/lvmdbusd/lvm_shell_proxy.py.in b/daemons/lvmdbusd/lvm_shell_proxy.py.in

index 1a5051a92..e106ca36f 100644

--- a/daemons/lvmdbusd/lvm_shell_proxy.py.in

+++ b/daemons/lvmdbusd/lvm_shell_proxy.py.in

@@ -19,7 +19,6 @@ import sys

 import tempfile

 import time

 import select

-import copy

 try:

 	import simplejson as json

@@ -31,8 +30,6 @@ from lvmdbusd.cfg import LVM_CMD

 from lvmdbusd.utils import log_debug, log_error, add_no_notify, make_non_block,\

 							read_decoded

-SHELL_PROMPT = "lvm> "

-

 def _quote_arg(arg):

 	if len(shlex.split(arg)) > 1:

@@ -43,10 +40,11 @@ def _quote_arg(arg):

 class LVMShellProxy(object):

-	# Read until we get prompt back and a result

-	# @param: no_output	Caller expects no output to report FD

-	# Returns stdout, report, stderr (report is JSON!)

-	def _read_until_prompt(self, no_output=False):

+	# Read REPORT FD until we have a complete and valid JSON record or give

+	# up trying to get one.

+	#

+	# Returns stdout, report (JSON), stderr

+	def _read_response(self):

 		stdout = ""

 		report = ""

 		stderr = ""

@@ -58,6 +56,7 @@ class LVMShellProxy(object):

 		# Try reading from all FDs to prevent one from filling up and causing

 		# a hang.  Keep reading until we get the prompt back and the report

 		# FD does not contain valid JSON

+

 		while keep_reading:

 			try:

 				rd_fd = [

@@ -78,32 +77,33 @@ class LVMShellProxy(object):

 				if self.lvm_shell.poll() is not None:

 					raise Exception(self.lvm_shell.returncode, "%s" % stderr)

-				if stdout.endswith(SHELL_PROMPT):

-					if no_output:

-						keep_reading = False

-					else:

-						cur_report_len = len(report)

-						if cur_report_len != 0:

-							# Only bother to parse if we have more data

-							if prev_report_len != cur_report_len:

-								prev_report_len = cur_report_len

-								# Parse the JSON if it's good we are done,

-								# if not we will try to read some more.

-								try:

-									report_json = json.loads(report)

-									keep_reading = False

-								except ValueError:

-									pass

-

-						if keep_reading:

-							extra_passes -= 1

-							if extra_passes <= 0:

-								if len(report):

-									raise ValueError("Invalid json: %s" %

-														report)

-								else:

-									raise ValueError(

-										"lvm returned no JSON output!")

+				cur_report_len = len(report)

+				if cur_report_len != 0:

+					# Only bother to parse if we have more data and the last 2 characters match expected

+					# complete JSON, prevents excessive JSON parsing attempts

+					if prev_report_len != cur_report_len and report[-2:] == "}\n":

+						prev_report_len = cur_report_len

+

+						# Parse the JSON if it's good we are done,

+						# if not we will try to read some more.

+						try:

+							report_json = json.loads(report)

+							keep_reading = False

+						except ValueError:

+							pass

+

+				# As long as lvm is spewing something on one of the FDs we will

+				# keep trying.  If we get a few timeouts with no activity, and

+				# we don't have valid JSON, we will raise an error.

+				if len(ready) == 0 and keep_reading:

+					extra_passes -= 1

+					if extra_passes <= 0:

+						if len(report):

+							raise ValueError("Invalid json: %s" %

+												report)

+						else:

+							raise ValueError(

+								"lvm returned no JSON output!")

 			except IOError as ioe:

 				log_debug(str(ioe))

@@ -118,7 +118,6 @@ class LVMShellProxy(object):

 		self.lvm_shell.stdin.flush()

 	def __init__(self):

-

 		# Create a temp directory

 		tmp_dir = tempfile.mkdtemp(prefix="lvmdbus_")

 		tmp_file = "%s/lvmdbus_report" % (tmp_dir)

@@ -139,6 +138,11 @@ class LVMShellProxy(object):

 		local_env = {"LC_ALL": "C", "LVM_REPORT_FD": "%s" % lvm_fd, "LVM_COMMAND_PROFILE": "lvmdbusd",

 					 "LVM_LOG_FILE_MAX_LINES": "0"}

+		# If any env variables contain LVM we will propagate them too

+		for k, v in os.environ.items():

+			if "LVM" in k:

+				local_env[k] = v

+

 		# run the lvm shell

 		self.lvm_shell = subprocess.Popen(

 			[LVM_CMD],

@@ -152,10 +156,9 @@ class LVMShellProxy(object):

 			# Close our copy of the lvm_fd, child process is open in its process space

 			os.close(lvm_fd)

-			# wait for the first prompt

-			errors = self._read_until_prompt(no_output=True)[2]

-			if errors and len(errors):

-				raise RuntimeError(errors)

+			# Assume we are ready as we may not get the lvm prompt message depending on

+			# if we are using readline or editline.

+

 		except:

 			raise

 		finally:

@@ -169,7 +172,7 @@ class LVMShellProxy(object):

 		self._write_cmd('lastlog\n')

 		# read everything from the STDOUT to the next prompt

-		stdout, report_json, stderr = self._read_until_prompt()

+		stdout, report_json, stderr = self._read_response()

 		if 'log' in report_json:

 			error_msg = ""

 			# Walk the entire log array and build an error string

@@ -203,7 +206,7 @@ class LVMShellProxy(object):

 		self._write_cmd(cmd)

 		# read everything from the STDOUT to the next prompt

-		stdout, report_json, stderr = self._read_until_prompt()

+		stdout, report_json, stderr = self._read_response()

 		# Parse the report to see what happened

 		if 'log' in report_json:

-- 

2.37.1