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

2 Aug 2023

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);

+}

    

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

Signed-off-by: Stefan Schantl stefan.schantl@ipfire.org