[PATCHv2,01/12] extrahd.cgi: Add various perl functions deal with block devices

  This functions are going to replace the former used scan/write to file/read from
file approach by directly collecting the required informations from the
kernel sysfs and devfs.

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
---
 html/cgi-bin/extrahd.cgi | 360 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 360 insertions(+)
  

Wouldn't it be more readable to give different names to local and global 
variables? ( see below )

Reviewed-by: Bernhard Bitsch <bbitsch@ipfire.org>

Am 01.08.2023 um 17:48 schrieb Stefan Schantl:
> This functions are going to replace the former used scan/write to file/read from
> file approach by directly collecting the required informations from the
> kernel sysfs and devfs.
> 
> Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
> ---
>   html/cgi-bin/extrahd.cgi | 360 +++++++++++++++++++++++++++++++++++++++
>   1 file changed, 360 insertions(+)
> 
> diff --git a/html/cgi-bin/extrahd.cgi b/html/cgi-bin/extrahd.cgi
> index 9dd3a0eee..5aadf15e8 100644
> --- a/html/cgi-bin/extrahd.cgi
> +++ b/html/cgi-bin/extrahd.cgi
> @@ -255,3 +255,363 @@ END
>   
>   &Header::closebigbox();
>   &Header::closepage();
> +
> +#
> +## Function which return an array with all available block devices.
> +#
> +sub get_block_devices () {
> +	my @devices;
> +
> +	# Open directory from kernel sysfs.
> +	opendir(DEVICES, "/sys/block");
> +
> +	# Loop through the directory.
> +	while(readdir(DEVICES)) {
> +		# Skip . and ..
> +		next if($_ =~ /^\.$/);
> +		next if($_ =~ /^\..$/);
> +
> +		# Skip any loopback and ram devices.
> +		next if($_ =~ "^loop");
> +		next if($_ =~ "^ram");
> +
> +		# Add the device to the array of found devices.
> +		push(@devices, $_);
> +	}
> +
> +	# Close directory handle.
> +	closedir(DEVICES);
> +
> +	# Return the devices array.
> +	return @devices;
> +}
> +
> +#
> +## Function which return all partitions of a given block device.
> +#
> +sub get_device_partitions ($) {
> +	my ($device) = @_;
> +
> +	# Array to store the known partitions for the given
> +	# device.
> +	my @partitions;
> +
> +	# Assign device directory.
> +	my $device_dir = "$sysfs_block_dir/$device";
> +
> +	# Abort and return nothing if the device dir does not exist.
> +	return unless(-d "$device_dir");
> +
> +	opendir(DEVICE, "$sysfs_block_dir/$device");
> +	while(readdir(DEVICE)) {
> +		next unless($_ =~ "^$device");
> +
> +		push(@partitions, $_);
> +	}
> +
> +	closedir(DEVICE);
> +
> +	@partitions = sort(@partitions);
> +
> +	return @partitions;
> +}
> +
> +#
> +## Returns the vendor of a given block device.
> +#
> +sub get_device_vendor ($) {
> +	my ($device) = @_;
> +
> +	# Assign device directory.
> +	my $device_dir = "$sysfs_block_dir/$device";
> +
> +	# Abort and return nothing if the device dir does not exist
> +	# or no vendor file exists.
> +	return unless(-d "$device_dir");
> +	return unless(-f "$device_dir/device/vendor");
> +
> +	# Open and read-in the device vendor.
> +	open(VENDOR, "$device_dir/device/vendor");
> +	my $vendor = <VENDOR>;
> +	close(VENDOR);
> +
> +	# Abort and return nothing if no vendor could be read.
> +	return unless($vendor);
> +
> +	# Remove any newlines from the vendor string.
> +	chomp($vendor);
> +
> +	# Return the omited vendor.
> +	return $vendor;
> +}
> +
> +#
> +## Returns the model name (string) of a given block device.
> +#
> +sub get_device_model ($) {
> +	my ($device) = @_;
> +
> +	# Assign device directory.
> +	my $device_dir = "$sysfs_block_dir/$device";
> +
> +	# Abort and return nothing if the device dir does not exist
> +	# or no model file exists.
> +	return unless(-d "$device_dir");
> +	return unless(-f "$device_dir/device/model");
> +
> +	# Open and read-in the device model.
> +	open(MODEL, "$device_dir/device/model");
> +	my $model = <MODEL>;
> +	close(MODEL);
> +
> +	# Abort and return nothing if no model could be read.
> +	return unless($model);
> +
> +	# Remove any newlines from the model string.
> +	chomp($model);
> +
> +	# Return the model string.
> +	return $model;
> +}
> +
> +#
> +## Returns the size of a given device in bytes.
> +#
> +sub get_device_size ($) {
> +	my ($device) = @_;
> +
> +	# Assign device directory.
> +	my $device_dir = "$sysfs_block_dir/$device";
> +
> +	# Abort and return nothing if the device dir does not exist
> +	# or no size file exists.
> +	return unless(-d "$device_dir");
> +	return unless(-f "$device_dir/size");
> +
> +	# Open and read-in the device size.
> +	open(SIZE, "$device_dir/size");
> +	my $size = <SIZE>;
> +	close(SIZE);
> +
> +	# Abort and return nothing if the size could not be read.
> +	return unless($size);
> +
> +	# Remove any newlines for the size string.
> +	chomp($size);
> +
> +	# The omited size only contains the amount of blocks from the
> +	# given device. To convert this into bytes we have to multiply this
> +	# value with 512 bytes for each block. This is a static value used by
> +	# the linux kernel.
> +	$size = $size * 512;
> +
> +	# Return the size in bytes.
> +	return $size;
> +}
> +
> +#
> +## Function which returns all currently mounted devices as a hash.
> +## example: "sda1" -> "/boot"
> +#
> +sub get_mountpoints () {
> +	my %mounts;
> +
> +	# Open and read-in the current mounts from the
> +	# kernel file system.
> +	open(MOUNT, "/proc/mounts");
> +
> +	# Loop through the known mounts.
> +	while(<MOUNT>) {
> +		# Skip mounts which does not belong to a device.
> +		next unless ($_ =~ "^/dev");
> +
> +		# Cut the line into pieces and assign nice variables.
> +		my ($dev, $mpoint, $fs, $options, $a, $b) = split(/ /, $_);
> +
> +		# Split the device name.
> +		my @tmp = split("/", $dev);
> +
> +		# Assign the plain device name to a new variable.
> +		# It is the last element of the array.
> +		my $device = $tmp[-1];
> +
> +		# Add the mountpoint to the hash of mountpoints.
> +		$mounts{"$device"} = $mpoint;
> +	}
> +
> +	# Close file handle.
> +	close(MOUNT);
> +
> +	# Return the hash of known mountpoints.
> +	return %mounts;
> +}
> +
> +sub get_swaps () {
> +	my @swaps;
> +
> +	# Open and read the swaps file.
> +	open(SWAP, "/proc/swaps");
> +
> +	# Loop though the file content.
> +	while(<SWAP>) {
> +		# Skip lines which does not belong to a device.
> +		next unless ($_ =~ "^/dev");
> +
> +		# Split the line and assign nice variables.
> +		my ($dev, $type, $size, $used, $prio) = split(/ /, $_);
> +
> +		# Cut the device line into pieces.
> +		my @tmp = split("/", $dev);
> +
> +		my $device = @tmp[-1];
> +
> +		# Add the found swap to the array of swaps.
> +		push(@swaps, $device);
> +	}
> +
> +	# Close file handle.
> +	close(SWAP);
> +
> +	# Sort the array.
> +	@swaps = sort(@swaps);
> +
> +	# Return the array.
> +	return @swaps;
> +}
> +
> +#
> +## Function with returns the mounted devices and the used filesystems as a hash.
> +## Example: "sda1" -> "ext4"
> +#
> +sub get_mountedfs () {
> +	my %mountedfs;
> +
> +	# Open and read the current mounts from the kernel
> +	# file system.
> +	open(MOUNT, "/proc/mounts");
> +
> +	# Loop through the known mounts.
> +	while(<MOUNT>) {
> +		# Skip mounts which does not belong to a device.
> +		next unless ($_ =~ "^/dev");
> +
> +		# Split line and assign nice variables.
> +		my ($dev, $mpoint, $fs, $options, $a, $b) = split(/ /, $_);
> +
> +		# Cut the device line into pieces.
> +		my @tmp = split("/", $dev);
> +
> +		# Assign the plain device name to a variable
> +		# It is the last element of the temporary array.
> +		my $device = $tmp[-1];
> +
> +		# Convert the filesystem into lower case format.
> +		$fs = lc($fs);
> +
> +		# Add the mounted file system.
> +		$mountedfs{$device} = $fs;
> +	}
> +
> +	# Close file handle.
> +	close(MOUNT);
> +
> +	# Return the hash with the mounted filesystems.
> +	return %mountedfs;
> +}
> +
> +#
> +## Function which returns all known UUID's as a hash.
> +## Example: "sda1" -> "1234-5678-abcd"
> +#
> +sub get_uuids () {
> +	my %uuids;
> +
> +	# Directory where the uuid mappings can be found.
> +	my $uuid_dir = "/dev/disk/by-uuid";
> +
> +	# Open uuid directory and read-in the current known uuids.
> +	opendir(UUIDS, "$uuid_dir");
> +
> +	# Loop through the uuids.
> +	foreach my $uuid (readdir(UUIDS)) {
> +		# Skip . and ..
> +		next if($uuid eq "." or $uuid eq "..");
> +
> +		# Skip everything which is not a symbolic link.
> +		next unless(-l "$uuid_dir/$uuid");
> +
> +		# Resolve the target of the symbolic link.
> +		my $target = readlink("$uuid_dir/$uuid");
> +
> +		# Split the link target into pieces.
> +		my @tmp = split("/", $target);
> +
> +		# Assign the last element of the array to the dev variable.
> +		my $dev = "$tmp[-1]";
> +
> +		# Add the device and uuid to the hash of uuids.
> +		$uuids{$dev} = $uuid;
> +	}
> +
> +	# Close directory handle.
> +	closedir(UUIDS);
> +
> +	# Return the hash of uuids.
> +	return %uuids;
> +}
> +
> +#
> +## Returns the device name of a given uuid.
> +#
> +sub device_by_uuid ($) {
> +	my ($uuid) = @_;
> +
> +	# Reverse the main uuids hash.
> +	my %uuids = reverse %uuids;

         my %uuids_l = reverse %uuids;
> +
> +	# Lookup and return the device name.
> +	return $uuids{$uuid};

         return $uuids_l{$uuid};

> +}
> +
> +#
> +## Returns "True" in case a given path is a known mountpoint.
> +#
> +sub is_mounted ($) {
> +	my ($mpoint) = @_;
> +
> +	my %mountpoints = reverse %mountpoints;

	my %mountpoints_l = reverse %mountpoints;

> +
> +	# Return "True" if the requested mountpoint is known and
> +	# therefore mounted.
> +	return 1 if($mountpoints{$mpoint});

	return 1 if($mountpoints_l{$mpoint});

> +}
> +
> +#
> +## Returns "True" if a given mountpoint is a subdirectory of one
> +## of the directories specified by the valid_mount_dirs array abouve.
> +#
> +sub is_valid_dir ($) {
> +	my ($mpoint) = @_;
> +
> +	# Split the given mountpoint into pieces and store them
> +	# in a temporay array.
> +	my @tmp = split("/", $mpoint);
> +
> +	# Exit and return nothing if the temporary array is empty.
> +	return unless(@tmp);
> +
> +	# Build the root path based on the given mount point.
> +	my $root_path = "/" . @tmp[1];
> +
> +	# Check if the root path is valid.
> +	return 1 if(grep /$root_path/, @valid_mount_dirs);
> +}
> +
> +#
> +# Returns "True" if a device is used as swap.
> +#
> +sub is_swap ($) {
> +	my ($device) = @_;
> +
> +	return 1 if(grep /$device/, @swaps);
> +}
  

> On Aug 2, 2023, at 6:39 AM, Bernhard Bitsch <bbitsch@ipfire.org> wrote:
> 
> Wouldn't it be more readable to give different names to local and global variables? ( see below )

+ 1

> 
> Reviewed-by: Bernhard Bitsch <bbitsch@ipfire.org <mailto:bbitsch@ipfire.org>>
> 
> Am 01.08.2023 um 17:48 schrieb Stefan Schantl:
>> This functions are going to replace the former used scan/write to file/read from
>> file approach by directly collecting the required informations from the
>> kernel sysfs and devfs.
>> Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
>> ---
>>  html/cgi-bin/extrahd.cgi | 360 +++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 360 insertions(+)
>> diff --git a/html/cgi-bin/extrahd.cgi b/html/cgi-bin/extrahd.cgi
>> index 9dd3a0eee..5aadf15e8 100644
>> --- a/html/cgi-bin/extrahd.cgi
>> +++ b/html/cgi-bin/extrahd.cgi
>> @@ -255,3 +255,363 @@ END
>>    &Header::closebigbox();
>>  &Header::closepage();
>> +
>> +#
>> +## Function which return an array with all available block devices.
>> +#
>> +sub get_block_devices () {
>> +	my @devices;
>> +
>> +	# Open directory from kernel sysfs.
>> +	opendir(DEVICES, "/sys/block");
>> +
>> +	# Loop through the directory.
>> +	while(readdir(DEVICES)) {
>> +		# Skip . and ..
>> +		next if($_ =~ /^\.$/);
>> +		next if($_ =~ /^\..$/);
>> +
>> +		# Skip any loopback and ram devices.
>> +		next if($_ =~ "^loop");
>> +		next if($_ =~ "^ram");
>> +
>> +		# Add the device to the array of found devices.
>> +		push(@devices, $_);
>> +	}
>> +
>> +	# Close directory handle.
>> +	closedir(DEVICES);
>> +
>> +	# Return the devices array.
>> +	return @devices;
>> +}
>> +
>> +#
>> +## Function which return all partitions of a given block device.
>> +#
>> +sub get_device_partitions ($) {
>> +	my ($device) = @_;
>> +
>> +	# Array to store the known partitions for the given
>> +	# device.
>> +	my @partitions;
>> +
>> +	# Assign device directory.
>> +	my $device_dir = "$sysfs_block_dir/$device";
>> +
>> +	# Abort and return nothing if the device dir does not exist.
>> +	return unless(-d "$device_dir");
>> +
>> +	opendir(DEVICE, "$sysfs_block_dir/$device");
>> +	while(readdir(DEVICE)) {
>> +		next unless($_ =~ "^$device");
>> +
>> +		push(@partitions, $_);
>> +	}
>> +
>> +	closedir(DEVICE);
>> +
>> +	@partitions = sort(@partitions);
>> +
>> +	return @partitions;
>> +}
>> +
>> +#
>> +## Returns the vendor of a given block device.
>> +#
>> +sub get_device_vendor ($) {
>> +	my ($device) = @_;
>> +
>> +	# Assign device directory.
>> +	my $device_dir = "$sysfs_block_dir/$device";
>> +
>> +	# Abort and return nothing if the device dir does not exist
>> +	# or no vendor file exists.
>> +	return unless(-d "$device_dir");
>> +	return unless(-f "$device_dir/device/vendor");
>> +
>> +	# Open and read-in the device vendor.
>> +	open(VENDOR, "$device_dir/device/vendor");
>> +	my $vendor = <VENDOR>;
>> +	close(VENDOR);
>> +
>> +	# Abort and return nothing if no vendor could be read.
>> +	return unless($vendor);
>> +
>> +	# Remove any newlines from the vendor string.
>> +	chomp($vendor);
>> +
>> +	# Return the omited vendor.
>> +	return $vendor;
>> +}
>> +
>> +#
>> +## Returns the model name (string) of a given block device.
>> +#
>> +sub get_device_model ($) {
>> +	my ($device) = @_;
>> +
>> +	# Assign device directory.
>> +	my $device_dir = "$sysfs_block_dir/$device";
>> +
>> +	# Abort and return nothing if the device dir does not exist
>> +	# or no model file exists.
>> +	return unless(-d "$device_dir");
>> +	return unless(-f "$device_dir/device/model");
>> +
>> +	# Open and read-in the device model.
>> +	open(MODEL, "$device_dir/device/model");
>> +	my $model = <MODEL>;
>> +	close(MODEL);
>> +
>> +	# Abort and return nothing if no model could be read.
>> +	return unless($model);
>> +
>> +	# Remove any newlines from the model string.
>> +	chomp($model);
>> +
>> +	# Return the model string.
>> +	return $model;
>> +}
>> +
>> +#
>> +## Returns the size of a given device in bytes.
>> +#
>> +sub get_device_size ($) {
>> +	my ($device) = @_;
>> +
>> +	# Assign device directory.
>> +	my $device_dir = "$sysfs_block_dir/$device";
>> +
>> +	# Abort and return nothing if the device dir does not exist
>> +	# or no size file exists.
>> +	return unless(-d "$device_dir");
>> +	return unless(-f "$device_dir/size");
>> +
>> +	# Open and read-in the device size.
>> +	open(SIZE, "$device_dir/size");
>> +	my $size = <SIZE>;
>> +	close(SIZE);
>> +
>> +	# Abort and return nothing if the size could not be read.
>> +	return unless($size);
>> +
>> +	# Remove any newlines for the size string.
>> +	chomp($size);
>> +
>> +	# The omited size only contains the amount of blocks from the
>> +	# given device. To convert this into bytes we have to multiply this
>> +	# value with 512 bytes for each block. This is a static value used by
>> +	# the linux kernel.
>> +	$size = $size * 512;
>> +
>> +	# Return the size in bytes.
>> +	return $size;
>> +}
>> +
>> +#
>> +## Function which returns all currently mounted devices as a hash.
>> +## example: "sda1" -> "/boot"
>> +#
>> +sub get_mountpoints () {
>> +	my %mounts;
>> +
>> +	# Open and read-in the current mounts from the
>> +	# kernel file system.
>> +	open(MOUNT, "/proc/mounts");
>> +
>> +	# Loop through the known mounts.
>> +	while(<MOUNT>) {
>> +		# Skip mounts which does not belong to a device.
>> +		next unless ($_ =~ "^/dev");
>> +
>> +		# Cut the line into pieces and assign nice variables.
>> +		my ($dev, $mpoint, $fs, $options, $a, $b) = split(/ /, $_);
>> +
>> +		# Split the device name.
>> +		my @tmp = split("/", $dev);
>> +
>> +		# Assign the plain device name to a new variable.
>> +		# It is the last element of the array.
>> +		my $device = $tmp[-1];
>> +
>> +		# Add the mountpoint to the hash of mountpoints.
>> +		$mounts{"$device"} = $mpoint;
>> +	}
>> +
>> +	# Close file handle.
>> +	close(MOUNT);
>> +
>> +	# Return the hash of known mountpoints.
>> +	return %mounts;
>> +}
>> +
>> +sub get_swaps () {
>> +	my @swaps;
>> +
>> +	# Open and read the swaps file.
>> +	open(SWAP, "/proc/swaps");
>> +
>> +	# Loop though the file content.
>> +	while(<SWAP>) {
>> +		# Skip lines which does not belong to a device.
>> +		next unless ($_ =~ "^/dev");
>> +
>> +		# Split the line and assign nice variables.
>> +		my ($dev, $type, $size, $used, $prio) = split(/ /, $_);
>> +
>> +		# Cut the device line into pieces.
>> +		my @tmp = split("/", $dev);
>> +
>> +		my $device = @tmp[-1];
>> +
>> +		# Add the found swap to the array of swaps.
>> +		push(@swaps, $device);
>> +	}
>> +
>> +	# Close file handle.
>> +	close(SWAP);
>> +
>> +	# Sort the array.
>> +	@swaps = sort(@swaps);
>> +
>> +	# Return the array.
>> +	return @swaps;
>> +}
>> +
>> +#
>> +## Function with returns the mounted devices and the used filesystems as a hash.
>> +## Example: "sda1" -> "ext4"
>> +#
>> +sub get_mountedfs () {
>> +	my %mountedfs;
>> +
>> +	# Open and read the current mounts from the kernel
>> +	# file system.
>> +	open(MOUNT, "/proc/mounts");
>> +
>> +	# Loop through the known mounts.
>> +	while(<MOUNT>) {
>> +		# Skip mounts which does not belong to a device.
>> +		next unless ($_ =~ "^/dev");
>> +
>> +		# Split line and assign nice variables.
>> +		my ($dev, $mpoint, $fs, $options, $a, $b) = split(/ /, $_);
>> +
>> +		# Cut the device line into pieces.
>> +		my @tmp = split("/", $dev);
>> +
>> +		# Assign the plain device name to a variable
>> +		# It is the last element of the temporary array.
>> +		my $device = $tmp[-1];
>> +
>> +		# Convert the filesystem into lower case format.
>> +		$fs = lc($fs);
>> +
>> +		# Add the mounted file system.
>> +		$mountedfs{$device} = $fs;
>> +	}
>> +
>> +	# Close file handle.
>> +	close(MOUNT);
>> +
>> +	# Return the hash with the mounted filesystems.
>> +	return %mountedfs;
>> +}
>> +
>> +#
>> +## Function which returns all known UUID's as a hash.
>> +## Example: "sda1" -> "1234-5678-abcd"
>> +#
>> +sub get_uuids () {
>> +	my %uuids;
>> +
>> +	# Directory where the uuid mappings can be found.
>> +	my $uuid_dir = "/dev/disk/by-uuid";
>> +
>> +	# Open uuid directory and read-in the current known uuids.
>> +	opendir(UUIDS, "$uuid_dir");
>> +
>> +	# Loop through the uuids.
>> +	foreach my $uuid (readdir(UUIDS)) {
>> +		# Skip . and ..
>> +		next if($uuid eq "." or $uuid eq "..");
>> +
>> +		# Skip everything which is not a symbolic link.
>> +		next unless(-l "$uuid_dir/$uuid");
>> +
>> +		# Resolve the target of the symbolic link.
>> +		my $target = readlink("$uuid_dir/$uuid");
>> +
>> +		# Split the link target into pieces.
>> +		my @tmp = split("/", $target);
>> +
>> +		# Assign the last element of the array to the dev variable.
>> +		my $dev = "$tmp[-1]";
>> +
>> +		# Add the device and uuid to the hash of uuids.
>> +		$uuids{$dev} = $uuid;
>> +	}
>> +
>> +	# Close directory handle.
>> +	closedir(UUIDS);
>> +
>> +	# Return the hash of uuids.
>> +	return %uuids;
>> +}
>> +
>> +#
>> +## Returns the device name of a given uuid.
>> +#
>> +sub device_by_uuid ($) {
>> +	my ($uuid) = @_;
>> +
>> +	# Reverse the main uuids hash.
>> +	my %uuids = reverse %uuids;
> 
>        my %uuids_l = reverse %uuids;
>> +
>> +	# Lookup and return the device name.
>> +	return $uuids{$uuid};
> 
>        return $uuids_l{$uuid};
> 
>> +}
>> +
>> +#
>> +## Returns "True" in case a given path is a known mountpoint.
>> +#
>> +sub is_mounted ($) {
>> +	my ($mpoint) = @_;
>> +
>> +	my %mountpoints = reverse %mountpoints;
> 
> 	my %mountpoints_l = reverse %mountpoints;
> 
>> +
>> +	# Return "True" if the requested mountpoint is known and
>> +	# therefore mounted.
>> +	return 1 if($mountpoints{$mpoint});
> 
> 	return 1 if($mountpoints_l{$mpoint});
> 
>> +}
>> +
>> +#
>> +## Returns "True" if a given mountpoint is a subdirectory of one
>> +## of the directories specified by the valid_mount_dirs array abouve.
>> +#
>> +sub is_valid_dir ($) {
>> +	my ($mpoint) = @_;
>> +
>> +	# Split the given mountpoint into pieces and store them
>> +	# in a temporay array.
>> +	my @tmp = split("/", $mpoint);
>> +
>> +	# Exit and return nothing if the temporary array is empty.
>> +	return unless(@tmp);
>> +
>> +	# Build the root path based on the given mount point.
>> +	my $root_path = "/" . @tmp[1];
>> +
>> +	# Check if the root path is valid.
>> +	return 1 if(grep /$root_path/, @valid_mount_dirs);
>> +}
>> +
>> +#
>> +# Returns "True" if a device is used as swap.
>> +#
>> +sub is_swap ($) {
>> +	my ($device) = @_;
>> +
>> +	return 1 if(grep /$device/, @swaps);
>> +}