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