From be1791ad6a09d08f6234ba53e45d022e3269dffd Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Mon, 13 Aug 2018 17:59:44 +0900
Subject: [PATCH] libudev-monitor: rename udev_has_devtmpfs() and move it to
 mount-util.c

As the function itself is quite generic.
---
 src/basic/mount-util.c        | 36 ++++++++++++++++++++++++++++++
 src/basic/mount-util.h        |  2 ++
 src/libudev/libudev-monitor.c | 42 +----------------------------------
 3 files changed, 39 insertions(+), 41 deletions(-)

diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index 1f9590ccb6..ae62d3090e 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -951,3 +951,39 @@ int mount_option_mangle(
 
         return 0;
 }
+
+int dev_is_devtmpfs(void) {
+        _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
+        char line[LINE_MAX], *e;
+        int mount_id, r;
+
+        r = path_get_mnt_id("/dev", &mount_id);
+        if (r < 0)
+                return r;
+
+        proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
+        if (!proc_self_mountinfo)
+                return -errno;
+
+        (void) __fsetlocking(proc_self_mountinfo, FSETLOCKING_BYCALLER);
+
+        FOREACH_LINE(line, proc_self_mountinfo, return -errno) {
+                int mid;
+
+                if (sscanf(line, "%i", &mid) != 1)
+                        continue;
+
+                if (mid != mount_id)
+                        continue;
+
+                e = strstr(line, " - ");
+                if (!e)
+                        continue;
+
+                /* accept any name that starts with the currently expected type */
+                if (startswith(e + 3, "devtmpfs"))
+                        return true;
+        }
+
+        return false;
+}
diff --git a/src/basic/mount-util.h b/src/basic/mount-util.h
index 3cfea3bb20..ad8c47cb32 100644
--- a/src/basic/mount-util.h
+++ b/src/basic/mount-util.h
@@ -54,3 +54,5 @@ int mount_option_mangle(
                 unsigned long mount_flags,
                 unsigned long *ret_mount_flags,
                 char **ret_remaining_options);
+
+int dev_is_devtmpfs(void);
diff --git a/src/libudev/libudev-monitor.c b/src/libudev/libudev-monitor.c
index f83115c95c..5ca035d43c 100644
--- a/src/libudev/libudev-monitor.c
+++ b/src/libudev/libudev-monitor.c
@@ -94,46 +94,6 @@ static struct udev_monitor *udev_monitor_new(struct udev *udev) {
         return udev_monitor;
 }
 
-/* we consider udev running when /dev is on devtmpfs */
-static bool udev_has_devtmpfs(struct udev *udev) {
-
-        _cleanup_fclose_ FILE *f = NULL;
-        char line[LINE_MAX], *e;
-        int mount_id, r;
-
-        r = path_get_mnt_id("/dev", &mount_id);
-        if (r < 0) {
-                if (r != -EOPNOTSUPP)
-                        log_debug_errno(r, "name_to_handle_at on /dev: %m");
-
-                return false;
-        }
-
-        f = fopen("/proc/self/mountinfo", "re");
-        if (!f)
-                return false;
-
-        FOREACH_LINE(line, f, return false) {
-                int mid;
-
-                if (sscanf(line, "%i", &mid) != 1)
-                        continue;
-
-                if (mid != mount_id)
-                        continue;
-
-                e = strstr(line, " - ");
-                if (!e)
-                        continue;
-
-                /* accept any name that starts with the currently expected type */
-                if (startswith(e + 3, "devtmpfs"))
-                        return true;
-        }
-
-        return false;
-}
-
 static void monitor_set_nl_address(struct udev_monitor *udev_monitor) {
         union sockaddr_union snl;
         socklen_t addrlen;
@@ -169,7 +129,7 @@ struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const c
                  * We do not set a netlink multicast group here, so the socket
                  * will not receive any messages.
                  */
-                if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) {
+                if (access("/run/udev/control", F_OK) < 0 && dev_is_devtmpfs() <= 0) {
                         log_debug("the udev service seems not to be active, disable the monitor");
                         group = UDEV_MONITOR_NONE;
                 } else