From 092ac9b6200b0c82a877713af54b665d3ea558e8 Mon Sep 17 00:00:00 2001
From: Tom Gundersen <teg@jklm.no>
Date: Fri, 17 Apr 2015 14:53:02 +0200
Subject: [PATCH] sd-device: uniformly handle missing devices

sd_device_new_from_* now returns -ENODEV when the device does not exist, and the enumerator
silently drops these errors as missing devices is exepected.
---
 src/libelogind/sd-device/sd-device.c         | 18 ++++++++++++------
 src/libsystemd/sd-device/device-enumerator.c | 14 ++++++++++----
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/src/libelogind/sd-device/sd-device.c b/src/libelogind/sd-device/sd-device.c
index 9dcb1a892..2e30b85ad 100644
--- a/src/libelogind/sd-device/sd-device.c
+++ b/src/libelogind/sd-device/sd-device.c
@@ -158,15 +158,21 @@ int device_set_syspath(sd_device *device, const char *_syspath, bool verify) {
 
         if (verify) {
                 r = readlink_and_canonicalize(_syspath, &syspath);
-                if (r == -EINVAL) {
+                if (r == -ENOENT)
+                        /* the device does not exist (any more?) */
+                        return -ENODEV;
+                else if (r == -EINVAL) {
                         /* not a symlink */
                         syspath = canonicalize_file_name(_syspath);
                         if (!syspath) {
+                                if (errno == ENOENT)
+                                        /* the device does not exist (any more?) */
+                                        return -ENODEV;
+
                                 log_debug("sd-device: could not canonicalize '%s': %m", _syspath);
                                 return -errno;
                         }
-                /* ignore errors due to the link not being a symlink */
-                } else if (r < 0 && r != -EINVAL) {
+                } else if (r < 0) {
                         log_debug("sd-device: could not get target of '%s': %s", _syspath, strerror(-r));
                         return r;
                 }
@@ -301,7 +307,7 @@ _public_ int sd_device_new_from_subsystem_sysname(sd_device **ret, const char *s
                         return sd_device_new_from_syspath(ret, syspath);
         }
 
-        return -ENOENT;
+        return -ENODEV;
 }
 
 int device_set_devtype(sd_device *device, const char *_devtype) {
@@ -627,7 +633,7 @@ _public_ int sd_device_new_from_device_id(sd_device **ret, const char *id) {
                 if (r < 0)
                         return r;
 
-                /* this si racey, so we might end up with the wrong device */
+                /* this is racey, so we might end up with the wrong device */
                 if (ifr.ifr_ifindex != ifindex)
                         return -ENODEV;
 
@@ -700,7 +706,7 @@ static int device_new_from_child(sd_device **ret, sd_device *child) {
                 return 0;
         }
 
-        return -ENOENT;
+        return -ENODEV;
 }
 
 _public_ int sd_device_get_parent(sd_device *child, sd_device **ret) {
diff --git a/src/libsystemd/sd-device/device-enumerator.c b/src/libsystemd/sd-device/device-enumerator.c
index 49c44bc47..d59da7d88 100644
--- a/src/libsystemd/sd-device/device-enumerator.c
+++ b/src/libsystemd/sd-device/device-enumerator.c
@@ -504,8 +504,10 @@ static int enumerator_scan_dir_and_add_devices(sd_device_enumerator *enumerator,
 
                 k = sd_device_new_from_syspath(&device, syspath);
                 if (k < 0) {
-                        log_debug_errno(k, "device-enumerator: failed to create device from syspath %s: %m", syspath);
-                        r = k;
+                        if (k != -ENODEV)
+                                /* this is necessarily racey, so ignore missing devices */
+                                r = k;
+
                         continue;
                 }
 
@@ -649,7 +651,10 @@ static int enumerator_scan_devices_tag(sd_device_enumerator *enumerator, const c
 
                 k = sd_device_new_from_device_id(&device, dent->d_name);
                 if (k < 0) {
-                        r = k;
+                        if (k != -ENODEV)
+                                /* this is necessarily racy, so ignore missing devices */
+                                r = k;
+
                         continue;
                 }
 
@@ -712,7 +717,8 @@ static int parent_add_child(sd_device_enumerator *enumerator, const char *path)
         int r;
 
         r = sd_device_new_from_syspath(&device, path);
-        if (r == -ENOENT)
+        if (r == -ENODEV)
+                /* this is necessarily racy, so ignore missing devices */
                 return 0;
         else if (r < 0)
                 return r;
-- 
2.30.2