From b6a2637524e4b94ba51abcf5ee42f3676c9755ed Mon Sep 17 00:00:00 2001
From: Kay Sievers <kay.sievers@vrfy.org>
Date: Thu, 10 Sep 2009 02:08:05 +0200
Subject: [PATCH] put util_create_path() and file creastion in a retry loop

On 8/29/09, Florian Zumbiehl <florz@florz.de> wrote:
> Could it happen that > util_create_path() and util_delete_path()
> do run in parallel for > the same directory? After all, util_create_path()
> does handle > the case where creation of the directory happens in parallel
> to it running, so it doesn't seem all that unlikely to me ...
---
 libudev/libudev-queue-private.c | 15 ++++++++----
 udev/udev-node.c                | 42 ++++++++++++++++++++++-----------
 2 files changed, 38 insertions(+), 19 deletions(-)

diff --git a/libudev/libudev-queue-private.c b/libudev/libudev-queue-private.c
index d9f7a67d1..4e67a1f9d 100644
--- a/libudev/libudev-queue-private.c
+++ b/libudev/libudev-queue-private.c
@@ -45,9 +45,9 @@
 #include <fcntl.h>
 #include <dirent.h>
 #include <limits.h>
+#include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <assert.h>
 
 #include "libudev.h"
 #include "libudev-private.h"
@@ -396,6 +396,7 @@ static void update_failed(struct udev_queue_export *udev_queue_export,
 {
 	struct udev *udev = udev_device_get_udev(udev_device);
 	char filename[UTIL_PATH_SIZE];
+	int err;
 
 	if (state != DEVICE_FAILED && udev_queue_export->failed_count == 0)
 		return;
@@ -408,10 +409,14 @@ static void update_failed(struct udev_queue_export *udev_queue_export,
 	case DEVICE_FAILED:
 		/* record event in the failed directory */
 		udev_queue_export->failed_count++;
-		util_create_path(udev, filename);
-		udev_selinux_setfscreatecon(udev, filename, S_IFLNK);
-		symlink(udev_device_get_devpath(udev_device), filename);
-		udev_selinux_resetfscreatecon(udev);
+		do {
+			util_create_path(udev, filename);
+			udev_selinux_setfscreatecon(udev, filename, S_IFLNK);
+			err = symlink(udev_device_get_devpath(udev_device), filename);
+			if (err != 0)
+				err = errno;
+			udev_selinux_resetfscreatecon(udev);
+		} while (err == ENOENT);
 		break;
 
 	case DEVICE_QUEUED:
diff --git a/udev/udev-node.c b/udev/udev-node.c
index 3685485eb..39bec3e16 100644
--- a/udev/udev-node.c
+++ b/udev/udev-node.c
@@ -77,10 +77,14 @@ int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mod
 		}
 	} else {
 		info(udev, "mknod(%s, %#o, (%u,%u))\n", file, mode, major(devnum), minor(devnum));
-		util_create_path(udev, file);
-		udev_selinux_setfscreatecon(udev, file, mode);
-		err = mknod(file, mode, devnum);
-		udev_selinux_resetfscreatecon(udev);
+		do {
+			util_create_path(udev, file);
+			udev_selinux_setfscreatecon(udev, file, mode);
+			err = mknod(file, mode, devnum);
+			if (err != 0)
+				err = errno;
+			udev_selinux_resetfscreatecon(udev);
+		} while (err == ENOENT);
 		if (err != 0) {
 			err(udev, "mknod(%s, %#o, (%u,%u) failed: %m\n", file, mode, major(devnum), minor(devnum));
 			goto exit;
@@ -175,10 +179,14 @@ static int node_symlink(struct udev *udev, const char *node, const char *slink)
 		}
 	} else {
 		info(udev, "creating symlink '%s' to '%s'\n", slink, target);
-		util_create_path(udev, slink);
-		udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
-		err = symlink(target, slink);
-		udev_selinux_resetfscreatecon(udev);
+		do {
+			util_create_path(udev, slink);
+			udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
+			err = symlink(target, slink);
+			if (err != 0)
+				err = errno;
+			udev_selinux_resetfscreatecon(udev);
+		} while (err == ENOENT);
 		if (err == 0)
 			goto exit;
 	}
@@ -186,10 +194,14 @@ static int node_symlink(struct udev *udev, const char *node, const char *slink)
 	info(udev, "atomically replace '%s'\n", slink);
 	util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
 	unlink(slink_tmp);
-	util_create_path(udev, slink);
-	udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
-	err = symlink(target, slink_tmp);
-	udev_selinux_resetfscreatecon(udev);
+	do {
+		util_create_path(udev, slink);
+		udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
+		err = symlink(target, slink_tmp);
+		if (err != 0)
+			err = errno;
+		udev_selinux_resetfscreatecon(udev);
+	} while (err == ENOENT);
 	if (err != 0) {
 		err(udev, "symlink(%s, %s) failed: %m\n", target, slink_tmp);
 		goto exit;
@@ -302,8 +314,10 @@ static void link_update(struct udev_device *dev, const char *slink, bool add)
 
 	if (add) {
 		dbg(udev, "creating index: '%s'\n", filename);
-		util_create_path(udev, filename);
-		symlink(udev_device_get_devpath(dev), filename);
+		do {
+			util_create_path(udev, filename);
+			symlink(udev_device_get_devpath(dev), filename);
+		} while (errno == ENOENT);
 	}
 }
 
-- 
2.30.2