From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 9 Nov 2021 11:40:39 +0000 (+0100)
Subject: inotify-util: improve reported error codes when inotify_add_watch() fails
X-Git-Tag: v250-rc1~324^2~5
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3777940ab283d41d317d0efd69abe8b0498bef4b;p=thirdparty%2Fsystemd.git

inotify-util: improve reported error codes when inotify_add_watch() fails
---

diff --git a/src/basic/inotify-util.c b/src/basic/inotify-util.c
index 848f8590fab..6da974dec03 100644
--- a/src/basic/inotify-util.c
+++ b/src/basic/inotify-util.c
@@ -2,14 +2,26 @@
 
 #include "fd-util.h"
 #include "inotify-util.h"
+#include "stat-util.h"
 
 int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
-        int wd;
+        int wd, r;
 
         /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
         wd = inotify_add_watch(fd, FORMAT_PROC_FD_PATH(what), mask);
-        if (wd < 0)
-                return -errno;
+        if (wd < 0) {
+                if (errno != ENOENT)
+                        return -errno;
+
+                /* Didn't work with ENOENT? If so, then either /proc/ isn't mounted, or the fd is bad */
+                r = proc_mounted();
+                if (r == 0)
+                        return -ENOSYS;
+                if (r > 0)
+                        return -EBADF;
+
+                return -ENOENT; /* OK, no clue, let's propagate the original error */
+        }
 
         return wd;
 }