From d66b197b227e1fbd4a72f002cb8b8a7ee9461062 Mon Sep 17 00:00:00 2001

From: "Brian C. Lane" <bcl@redhat.com>

Date: Thu, 6 Aug 2015 07:17:14 -0700

Subject: [PATCH 19/20] libparted: Use read only when probing devices on linux

 (#1245144)

When a device is opened for RW closing it can trigger other actions,

like udev scanning it for partition changes. Use read only for the

init_* methods and RW for actual changes to the device.

This adds _device_open which takes mode flags as an argument and turns

linux_open into a wrapper for it with RW_MODE.

_device_open_ro is added to open the device with RD_MODE and increment

the open_counter. This is used in the init_* functions.

_device_close is a wrapper around linux_close that decrements the

open_counter and is used in the init_* functions.

All of these changes are self-contained with no external API changes.

The only visible change in behavior is that when a new PedDevice is

created the device is opened in RO_MODE instead of RW_MODE.

Resolves: rhbz#1245144

(cherry picked from commit 0e169215efcdb33d588ddc2267467593bbf717c9)

---

 libparted/arch/linux.c | 62 +++++++++++++++++++++++++++++++++++---------------

 1 file changed, 44 insertions(+), 18 deletions(-)

diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c

index b68130b..3934a5b 100644

--- a/libparted/arch/linux.c

+++ b/libparted/arch/linux.c

@@ -291,7 +291,9 @@ struct blkdev_ioctl_param {

 static char* _device_get_part_path (PedDevice const *dev, int num);

 static int _partition_is_mounted_by_path (const char* path);

 static unsigned int _device_get_partition_range(PedDevice const* dev);

-

+static int _device_open (PedDevice* dev, int flags);

+static int _device_open_ro (PedDevice* dev);

+static int _device_close (PedDevice* dev);

 static int

 _read_fd (int fd, char **buf)

@@ -910,7 +912,7 @@ init_ide (PedDevice* dev)

         if (!_device_stat (dev, &dev_stat))

                 goto error;

-        if (!ped_device_open (dev))

+        if (!_device_open_ro (dev))

                 goto error;

         if (ioctl (arch_specific->fd, HDIO_GET_IDENTITY, &hdi)) {

@@ -979,11 +981,11 @@ init_ide (PedDevice* dev)

         if (!_device_probe_geometry (dev))

                 goto error_close_dev;

-        ped_device_close (dev);

+        _device_close (dev);

         return 1;

 error_close_dev:

-        ped_device_close (dev);

+        _device_close (dev);

 error:

         return 0;

 }

@@ -1116,7 +1118,7 @@ init_scsi (PedDevice* dev)

         char* vendor;

         char* product;

-        if (!ped_device_open (dev))

+        if (!_device_open_ro (dev))

                 goto error;

         if (ioctl (arch_specific->fd, SCSI_IOCTL_GET_IDLUN, &idlun) < 0) {

@@ -1130,7 +1132,7 @@ init_scsi (PedDevice* dev)

                         goto error_close_dev;

                 if (!_device_probe_geometry (dev))

                         goto error_close_dev;

-                ped_device_close (dev);

+                _device_close (dev);

                 return 1;

         }

@@ -1152,11 +1154,11 @@ init_scsi (PedDevice* dev)

         if (!_device_probe_geometry (dev))

                 goto error_close_dev;

-        ped_device_close (dev);

+        _device_close (dev);

         return 1;

 error_close_dev:

-        ped_device_close (dev);

+        _device_close (dev);

 error:

         return 0;

 }

@@ -1168,7 +1170,7 @@ init_file (PedDevice* dev)

         if (!_device_stat (dev, &dev_stat))

                 goto error;

-        if (!ped_device_open (dev))

+        if (!_device_open_ro (dev))

                 goto error;

         dev->sector_size = PED_SECTOR_SIZE_DEFAULT;

@@ -1195,7 +1197,7 @@ init_file (PedDevice* dev)

                 goto error_close_dev;

         }

-        ped_device_close (dev);

+        _device_close (dev);

         dev->bios_geom.cylinders = dev->length / 4 / 32;

         dev->bios_geom.heads = 4;

@@ -1206,7 +1208,7 @@ init_file (PedDevice* dev)

         return 1;

 error_close_dev:

-        ped_device_close (dev);

+        _device_close (dev);

 error:

         return 0;

 }

@@ -1222,7 +1224,7 @@ init_dasd (PedDevice* dev, const char* model_name)

         if (!_device_stat (dev, &dev_stat))

                 goto error;

-        if (!ped_device_open (dev))

+        if (!_device_open_ro (dev))

                 goto error;

         LinuxSpecific* arch_specific = LINUX_SPECIFIC (dev);

@@ -1262,11 +1264,11 @@ init_dasd (PedDevice* dev, const char* model_name)

         dev->model = strdup (model_name);

-        ped_device_close (dev);

+        _device_close (dev);

         return 1;

 error_close_dev:

-        ped_device_close (dev);

+        _device_close (dev);

 error:

         return 0;

 }

@@ -1281,7 +1283,7 @@ init_generic (PedDevice* dev, const char* model_name)

         if (!_device_stat (dev, &dev_stat))

                 goto error;

-        if (!ped_device_open (dev))

+        if (!_device_open_ro (dev))

                 goto error;

         ped_exception_fetch_all ();

@@ -1329,11 +1331,11 @@ init_generic (PedDevice* dev, const char* model_name)

         dev->model = strdup (model_name);

-        ped_device_close (dev);

+        _device_close (dev);

         return 1;

 error_close_dev:

-        ped_device_close (dev);

+        _device_close (dev);

 error:

         return 0;

 }

@@ -1620,12 +1622,27 @@ retry:

 }

 static int

+_device_open_ro (PedDevice* dev)

+{

+    int rc = _device_open (dev, RD_MODE);

+    if (rc)

+        dev->open_count++;

+    return rc;

+}

+

+static int

 linux_open (PedDevice* dev)

 {

+    return _device_open (dev, RW_MODE);

+}

+

+static int

+_device_open (PedDevice* dev, int flags)

+{

         LinuxSpecific*  arch_specific = LINUX_SPECIFIC (dev);

 retry:

-        arch_specific->fd = open (dev->path, RW_MODE);

+        arch_specific->fd = open (dev->path, flags);

         if (arch_specific->fd == -1) {

                 char*   rw_error_msg = strerror (errno);

@@ -1694,6 +1711,15 @@ linux_refresh_close (PedDevice* dev)

         return 1;

 }

+static int

+_device_close (PedDevice* dev)

+{

+    int rc = linux_close (dev);

+    if (dev->open_count > 0)

+        dev->open_count--;

+    return rc;

+}

+

 #if SIZEOF_OFF_T < 8

 static _syscall5(int,_llseek,

-- 

2.4.3