From d2c4df9e48c07f31912c6f3d3686f569b50747de Mon Sep 17 00:00:00 2001
From: Mike Yuan <me@yhndnzj.com>
Date: Thu, 13 Mar 2025 14:54:04 +0100
Subject: [PATCH] pidfd-util: use get_proc_field() for pidfd_get_pid_fdinfo()

---
 src/basic/pidfd-util.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/src/basic/pidfd-util.c b/src/basic/pidfd-util.c
index edd2848d07..52a371ba1a 100644
--- a/src/basic/pidfd-util.c
+++ b/src/basic/pidfd-util.c
@@ -89,26 +89,21 @@ static int pidfd_get_info(int fd, struct pidfd_info *info) {
 
 static int pidfd_get_pid_fdinfo(int fd, pid_t *ret) {
         char path[STRLEN("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)];
-        _cleanup_free_ char *fdinfo = NULL;
+        _cleanup_free_ char *p = NULL;
         int r;
 
         assert(fd >= 0);
 
         xsprintf(path, "/proc/self/fdinfo/%i", fd);
 
-        r = read_full_virtual_file(path, &fdinfo, NULL);
+        r = get_proc_field(path, "Pid", &p);
         if (r == -ENOENT)
-                return proc_fd_enoent_errno();
+                return -EBADF;
+        if (r == -ENODATA) /* not a pidfd? */
+                return -ENOTTY;
         if (r < 0)
                 return r;
 
-        char *p = find_line_startswith(fdinfo, "Pid:");
-        if (!p)
-                return -ENOTTY; /* not a pidfd? */
-
-        p = skip_leading_chars(p, /* bad = */ NULL);
-        p[strcspn(p, WHITESPACE)] = 0;
-
         if (streq(p, "0"))
                 return -EREMOTE; /* PID is in foreign PID namespace? */
         if (streq(p, "-1"))