distrib-compat 0.1-5: Backport upstream killproc fixes from bitstreamout/killproc

[dcasota]

Summary

Backport critical bug fixes and robustness improvements from Werner Fink's upstream killproc v2.23 into distrib-compat 0.1. This update bumps the release from 0.1-4 to 0.1-5 by adding a single new patch file (Patch1) while preserving the unmodified Source0 tarball and its SHA-512 checksum.

Motivation

Photon OS's distrib-compat package (providing startproc, killproc, checkproc) is a simplified fork of Werner Fink's killproc suite, originally developed for SUSE/openSUSE. The upstream project has accumulated several important fixes since the fork point that address real-world failure scenarios:

• Process name matching failures for binaries with names longer than 15 characters
• Race conditions during daemon startup
• Incorrect SIGKILL escalation behavior
• Permission errors for non-root users and NFS-mounted executables

Source Provenance and Upstream Attribution

All backported code originates from Werner Fink's bitstreamout/killproc repository. The original source files carry the following copyright headers:

Copyright 1994-2000 Werner Fink, 1996-2000 SuSE GmbH Nuernberg, Germany.
Copyright 2005 Werner Fink, 2005 SUSE LINUX Products GmbH, Germany.
Author: Werner Fink <werner@suse.de>

The distrib-compat package was created by Ankit Jain (VMware) in 2021 as a simplified multicall-binary adaptation of Werner Fink's killproc suite for Photon OS compatibility.

License Compliance

Component	License	SPDX Identifier
Upstream killproc (bitstreamout/killproc)	GNU GPL v2 "or any later version"	GPL-2.0-or-later
distrib-compat source (COPYING)	GNU GPL v2 "or any later version"	GPL-2.0-or-later
distrib-compat package metadata (license.txt)	GPL-2.0-only AND GPL-2.0-or-later	GPL-2.0-only AND GPL-2.0-or-later
config.yaml SPDX	license_concluded: GPL-2.0-or-later AND GPL-2.0-only	--

The backported code is licensed under GPL-2.0-or-later (per upstream source file headers), which is fully compatible with the existing distrib-compat license declaration. All modifications are derivative works under the same GPL-2.0 terms. No license change is required.

Changes

High Priority -- Correctness Fixes

1. COMM_LEN process name truncation (libinit.h): Added COMM_LEN constant (15 chars) and rewrote swap_name() to use strncat() with proper truncation. The Linux kernel truncates /proc/<pid>/stat comm field to 15 characters; without this fix, killproc/checkproc fail to match processes whose binary name exceeds 15 characters (e.g., NetworkManager, systemd-resolved).

2. sig_forced flag (killproc.c): Added a boolean flag that prevents unwanted SIGKILL escalation when the user explicitly specifies a signal (e.g., killproc -SIGTERM /path/to/daemon). Previously, killproc would always escalate to SIGKILL after timeout, even when SIGTERM was explicitly requested.

3. pipe2() parent-child synchronization (startproc.c): Replaced the previous fork/exec sequence with pipe-based synchronization using pipe2(O_CLOEXEC) (with pipe()+fcntl() fallback). This eliminates a race condition where the parent would check /proc/<pid>/exe before the child had completed execve(), causing spurious "start of ... failed" errors, particularly under system load.

Medium Priority -- Robustness Improvements

4. UID-based fallback (libinit.c): In pidof(), verify_pidfile(), and check_pids(), added fallback logic for non-root users when readlink(/proc/<pid>/exe) returns EACCES. Falls back to stat-based name matching using the caller's UID, enabling process checks by service users without elevated privileges.

5. expandpath() function (libinit.c, libinit.h): Added a 96-line realpath() alternative that avoids lstat() calls which can hang indefinitely on unresponsive NFS mounts. Used in pidof(), verify_pidfile(), and check_pids() for safe path resolution.

6. O_CLOEXEC on script open (libinit.c): Added O_CLOEXEC flag to the open() call in isscript() to prevent file descriptor leaks to child processes.

7. atexit(undo_proc) cleanup (libinit.c): Added automatic /proc unmount on exit if the tool had to mount it, preventing stale mounts.

8. Bonus: Fixed uninitialized variable p warning in waiton() (startproc.c) -- a pre-existing issue not related to the backport but resolved to achieve a warning-free build.

Files Changed

• SPECS/distrib-compat/distrib-compat.spec -- Release bump 4 -> 5, added Patch1, changelog entry
• SPECS/distrib-compat/distrib-compat-upstream-backports.patch -- New 580-line unified diff (Patch1)

The patch modifies 4 source files within the tarball:

• libinit.h -- COMM_LEN constant, swap_name() rewrite, expandpath() declaration
• libinit.c -- expandpath(), UID fallback, O_CLOEXEC, atexit cleanup
• killproc.c -- sig_forced flag
• startproc.c -- pipe2() sync, waiton() fix

Testing

Build Verification

• Platform: VMware Photon OS 5.0 (PHOTON_BUILD_NUMBER=b9d98344d)
• Compiler: GCC 12.2.0
• Result: Zero errors, zero warnings
• Binary: ELF 64-bit LSB PIE executable, x86-64, dynamically linked, with debug_info

Patch Application

• Both Patch0 (distrib-compat-gen-debuginfo.patch) and Patch1 (distrib-compat-upstream-backports.patch) apply cleanly in sequence to an unmodified extraction of distrib-compat-0.1.tar.bz2
• Source0 tarball and SHA-512 checksum are unchanged

Smoke Tests

Test	Command	Result
Signal listing	killproc -l	All 64 signals listed correctly
Running process check	checkproc -v /usr/bin/bash	Exit 0, PIDs listed
Missing binary check	checkproc -v /usr/bin/nonexistent	Exit 5 (LSB_NOENTR)
Symlink dispatch	ls -la /sbin/{killproc,checkproc,startproc}	All symlinks to proctools

Fork Verification

Build and tests were additionally verified using the dcasota/photon fork's 5.0 branch, confirming that the spec and patch files from the fork's SPECS/distrib-compat/ directory are identical to vmware/photon:5.0 and that the changes apply cleanly.

Reviewer Guidance

Suggested test scenarios for extended validation:

1. COMM_LEN fix: Test checkproc / killproc with daemons whose binary names exceed 15 characters (e.g., NetworkManager, systemd-resolved, systemd-timesyncd)
2. sig_forced: Verify killproc -SIGTERM /path/to/daemon does not escalate to SIGKILL
3. Non-root: Run checkproc as a non-root user against a process owned by that user
4. NFS: If applicable, test on systems with NFS-mounted /usr or /opt