From d6e15a60e84c1511523aa81272b7db7a6ec441d0 Mon Sep 17 00:00:00 2001 From: Ovidiu Panait Date: Tue, 26 Sep 2017 08:04:58 +0000 Subject: [PATCH] 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 Upstream-Status: Backport Author: Brian C. Lane Signed-off-by: Ovidiu Panait --- 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 f612617..0a06a54 100644 --- a/libparted/arch/linux.c +++ b/libparted/arch/linux.c @@ -294,7 +294,9 @@ 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) @@ -913,7 +915,7 @@ 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)) { @@ -982,11 +984,11 @@ 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; } @@ -1119,7 +1121,7 @@ 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) { @@ -1133,7 +1135,7 @@ 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; } @@ -1155,11 +1157,11 @@ 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; } @@ -1171,7 +1173,7 @@ 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; @@ -1198,7 +1200,7 @@ 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; @@ -1209,7 +1211,7 @@ init_file (PedDevice* dev) return 1; error_close_dev: - ped_device_close (dev); + _device_close (dev); error: return 0; } @@ -1225,7 +1227,7 @@ 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); @@ -1265,11 +1267,11 @@ 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; } @@ -1284,7 +1286,7 @@ 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 (); @@ -1332,11 +1334,11 @@ 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; } @@ -1623,12 +1625,27 @@ 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); @@ -1697,6 +1714,15 @@ 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 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20) -- 2.11.0