From 3589d6c01fd962b6c4a831180cef47aef0c60cc0 Mon Sep 17 00:00:00 2001
From: Mike Yuan <me@yhndnzj.com>
Date: Wed, 30 Apr 2025 19:43:20 +0200
Subject: [PATCH] process-util: assert on pid in procfs_file_alloca(), use
 strjoina()

---
 src/basic/process-util.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/basic/process-util.h b/src/basic/process-util.h
index fd24ee41ce..df6daf1839 100644
--- a/src/basic/process-util.h
+++ b/src/basic/process-util.h
@@ -12,6 +12,7 @@
 #include <sys/types.h>
 
 #include "alloc-util.h"
+#include "assert-util.h"
 #include "format-util.h"
 #include "macro.h"
 #include "pidref.h"
@@ -22,10 +23,10 @@
                 pid_t _pid_ = (pid);                                    \
                 const char *_field_ = (field);                          \
                 char *_r_;                                              \
-                if (_pid_ == 0) {                                       \
-                        _r_ = newa(char, STRLEN("/proc/self/") + strlen(_field_) + 1); \
-                        strcpy(stpcpy(_r_, "/proc/self/"), _field_);    \
-                } else {                                                \
+                if (_pid_ == 0)                                         \
+                        _r_ = strjoina("/proc/self/", _field_);         \
+                else {                                                  \
+                        assert(_pid_ > 0);                              \
                         _r_ = newa(char, STRLEN("/proc/") + DECIMAL_STR_MAX(pid_t) + 1 + strlen(_field_) + 1); \
                         sprintf(_r_, "/proc/" PID_FMT "/%s", _pid_, _field_); \
                 }                                                       \