cryostat_genesis.kv

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cryostat_genesis.kv     1 ------------------------------------------------------------------------------
cryostat_genesis.kv     2 ------------------------------------------------------------------------------
cryostat_genesis.kv     3 -- This file is part of 'Cryostat', an Ada library for persistent storage.  --
cryostat_genesis.kv     4 --                                                                          --
cryostat_genesis.kv     5 -- (C) 2020 Stanislav Datskovskiy ( www.loper-os.org )                      --
cryostat_genesis.kv     6 -- http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     --
cryostat_genesis.kv     7 --                                                                          --
cryostat_genesis.kv     8 -- You do not have, nor can you ever acquire the right to use, copy or      --
cryostat_genesis.kv     9 -- distribute this software ; Should you use this software for any purpose, --
cryostat_genesis.kv    10 -- or copy and distribute it to anyone or in any manner, you are breaking   --
cryostat_genesis.kv    11 -- the laws of whatever soi-disant jurisdiction, and you promise to         --
cryostat_genesis.kv    12 -- continue doing so for the indefinite future. In any case, please         --
cryostat_genesis.kv    13 -- always : read and understand any software ; verify any PGP signatures    --
cryostat_genesis.kv    14 -- that you use - for any purpose.                                          --
cryostat_genesis.kv    15 ------------------------------------------------------------------------------
cryostat_genesis.kv    16 ------------------------------------------------------------------------------
cryostat_genesis.kv    17 
cryostat_genesis.kv    18 with System; use System;
cryostat_genesis.kv    19 
cryostat_genesis.kv    20 
cryostat_genesis.kv    21 package body PMaps is
cryostat_genesis.kv    22    
cryostat_genesis.kv    23    -- Open a backing file at Path, with given params, for use with Initialize
cryostat_genesis.kv    24    function OpenMapFile(Path     : in  String;
cryostat_genesis.kv    25                         Writable : in  Boolean := False;
cryostat_genesis.kv    26                         Create   : in  Boolean := False) return FD is
cryostat_genesis.kv    27       
cryostat_genesis.kv    28       -- Buffer for converting the civilized Path string to a C-style string :
cryostat_genesis.kv    29       CPath     : String(1 .. Path'Length + 1) := (others => Character'Val(0));
cryostat_genesis.kv    30       
cryostat_genesis.kv    31       -- Unix FD handle for the backing file, obtained by Open()
cryostat_genesis.kv    32       FileFD    : FD;
cryostat_genesis.kv    33       
cryostat_genesis.kv    34       -- Flags provided to Open() -- default 'read only'
cryostat_genesis.kv    35       COpenFlag : O_Flags := O_RDONLY;
cryostat_genesis.kv    36       
cryostat_genesis.kv    37    begin
cryostat_genesis.kv    38       
cryostat_genesis.kv    39       -- Convert civilized string to the barbaric type expected by Open() :
cryostat_genesis.kv    40       CPath(Path'Range) := Path;
cryostat_genesis.kv    41       
cryostat_genesis.kv    42       -- Set the writability flag for Open() if Writable is enabled :
cryostat_genesis.kv    43       if Writable then
cryostat_genesis.kv    44          COpenFlag := O_RDWR;
cryostat_genesis.kv    45       end if;
cryostat_genesis.kv    46       
cryostat_genesis.kv    47       -- If file does not exist, and Create is enabled, it will be created :
cryostat_genesis.kv    48       if Create then
cryostat_genesis.kv    49          COpenFlag := COpenFlag or O_CREAT;
cryostat_genesis.kv    50       end if;
cryostat_genesis.kv    51       
cryostat_genesis.kv    52       -- Open the file :
cryostat_genesis.kv    53       FileFD := Open(CPath'Address, COpenFlag);
cryostat_genesis.kv    54       
cryostat_genesis.kv    55       -- If Open() failed, eggog :
cryostat_genesis.kv    56       if FileFD = FD_EGGOG then
cryostat_genesis.kv    57          raise PMapFailedOpen with "PMap: Failed to Open backing file";
cryostat_genesis.kv    58       end if;
cryostat_genesis.kv    59       
cryostat_genesis.kv    60       -- Return the FD of the backing file :
cryostat_genesis.kv    61       return FileFD;
cryostat_genesis.kv    62       
cryostat_genesis.kv    63    end OpenMapFile;
cryostat_genesis.kv    64    
cryostat_genesis.kv    65    
cryostat_genesis.kv    66    -- Initialize a new map
cryostat_genesis.kv    67    procedure Initialize(Map : in out PMap) is
cryostat_genesis.kv    68       
cryostat_genesis.kv    69       -- Prot flags to be given to MMap()
cryostat_genesis.kv    70       MProtFlag : MM_Prot := PROT_READ;
cryostat_genesis.kv    71       
cryostat_genesis.kv    72       -- Result code returned by FTruncate()
cryostat_genesis.kv    73       CErr      : Unix_Int;
cryostat_genesis.kv    74       
cryostat_genesis.kv    75    begin
cryostat_genesis.kv    76       
cryostat_genesis.kv    77       -- Check that we have not already Open'd:
cryostat_genesis.kv    78       if Map.Status /= Stop then
cryostat_genesis.kv    79          Map.Status := Eggog;
cryostat_genesis.kv    80          raise PMapFailedOpen with "PMap: already Opened backing file";
cryostat_genesis.kv    81       end if;
cryostat_genesis.kv    82       
cryostat_genesis.kv    83       -- If Write is enabled, set the appropriate flag for MMap() :
cryostat_genesis.kv    84       if Map.MapWritable then
cryostat_genesis.kv    85          MProtFlag := PROT_READ or PROT_WRITE;
cryostat_genesis.kv    86       end if;
cryostat_genesis.kv    87       
cryostat_genesis.kv    88       -- If creating, pad the backing file to the payload size :
cryostat_genesis.kv    89       if Map.MapCreate then
cryostat_genesis.kv    90          CErr := FTruncate(Map.FileFD, Map.MapLength);
cryostat_genesis.kv    91          if CErr /= 0 then
cryostat_genesis.kv    92             Map.Status := Eggog;
cryostat_genesis.kv    93             raise PMapFailedOpen with "PMap: Failed to FTruncate backing file";
cryostat_genesis.kv    94          end if;
cryostat_genesis.kv    95       end if;
cryostat_genesis.kv    96       
cryostat_genesis.kv    97       -- Ask the OS to set up the map itself:
cryostat_genesis.kv    98       Map.Address := MMap(Length => Map.MapLength,
cryostat_genesis.kv    99                           Off_T  => Map.MapOffset,
cryostat_genesis.kv   100                           Prot   => MProtFlag,
cryostat_genesis.kv   101                           Flags  => MAP_SHARED,
cryostat_genesis.kv   102                           Handle => Map.FileFD);
cryostat_genesis.kv   103       
cryostat_genesis.kv   104       -- Test for failure of MMap() call :
cryostat_genesis.kv   105       if Map.Address = MAP_FAILED then
cryostat_genesis.kv   106          Map.Status := Eggog;
cryostat_genesis.kv   107          raise PMapFailedMMap with "PMap: MAP_FAILED";
cryostat_genesis.kv   108       end if;
cryostat_genesis.kv   109       
cryostat_genesis.kv   110       if Map.Address = NullPtr then
cryostat_genesis.kv   111          Map.Status := Eggog;
cryostat_genesis.kv   112          raise PMapFailedAddr with "PMap: Map Address is Null";
cryostat_genesis.kv   113       end if;
cryostat_genesis.kv   114       
cryostat_genesis.kv   115       -- If no failure detected, mark the map as usable :
cryostat_genesis.kv   116       Map.Status := Run;
cryostat_genesis.kv   117       
cryostat_genesis.kv   118    end Initialize;
cryostat_genesis.kv   119    
cryostat_genesis.kv   120    
cryostat_genesis.kv   121    -- Test whether a map is operating
cryostat_genesis.kv   122    function IsReady(Map : in PMap) return Boolean is
cryostat_genesis.kv   123    begin
cryostat_genesis.kv   124       
cryostat_genesis.kv   125       return Map.Status = Run;
cryostat_genesis.kv   126       
cryostat_genesis.kv   127    end IsReady;
cryostat_genesis.kv   128    
cryostat_genesis.kv   129    
cryostat_genesis.kv   130    -- Retrieve the memory address where the map payload resides
cryostat_genesis.kv   131    function GetAddress(Map : in PMap) return MapAddress is
cryostat_genesis.kv   132    begin
cryostat_genesis.kv   133       
cryostat_genesis.kv   134       -- Ensure that the map is active :
cryostat_genesis.kv   135       if not IsReady(Map) then
cryostat_genesis.kv   136          raise PMapNotRunning with "PMap: GetAddress on inactive Map";
cryostat_genesis.kv   137       end if;
cryostat_genesis.kv   138       
cryostat_genesis.kv   139       -- Return the address :
cryostat_genesis.kv   140       return Map.Address;
cryostat_genesis.kv   141       
cryostat_genesis.kv   142    end GetAddress;
cryostat_genesis.kv   143    
cryostat_genesis.kv   144    
cryostat_genesis.kv   145    -- Zeroize the map, if it is writable
cryostat_genesis.kv   146    procedure Zap(Map : in out PMap) is
cryostat_genesis.kv   147       
cryostat_genesis.kv   148       -- Represent the map's payload as a byte array across full length :
cryostat_genesis.kv   149       RawArray : array(1 .. Map.MapLength) of Byte;
cryostat_genesis.kv   150       for RawArray'Address use Map.Address;
cryostat_genesis.kv   151       
cryostat_genesis.kv   152    begin
cryostat_genesis.kv   153       
cryostat_genesis.kv   154       -- If map is inactive, do nothing :
cryostat_genesis.kv   155       if not IsReady(Map) then
cryostat_genesis.kv   156          return;
cryostat_genesis.kv   157       end if;
cryostat_genesis.kv   158       
cryostat_genesis.kv   159       -- If tried to zap a read-only map, eggog :
cryostat_genesis.kv   160       if Map.MapWritable = False then
cryostat_genesis.kv   161          raise PMapNotWritable with "PMap: Tried to Zap a Read-Only Map";
cryostat_genesis.kv   162       end if;
cryostat_genesis.kv   163       
cryostat_genesis.kv   164       -- Zeroize the payload of the map :
cryostat_genesis.kv   165       RawArray := (others => 0);
cryostat_genesis.kv   166       
cryostat_genesis.kv   167    end Zap;
cryostat_genesis.kv   168    
cryostat_genesis.kv   169    
cryostat_genesis.kv   170    -- Sync the map to disk
cryostat_genesis.kv   171    procedure Sync(Map : in out PMap) is
cryostat_genesis.kv   172       
cryostat_genesis.kv   173       -- Result code returned by MSync() and Close()
cryostat_genesis.kv   174       CErr : Unix_Int := 0;
cryostat_genesis.kv   175       
cryostat_genesis.kv   176    begin
cryostat_genesis.kv   177       
cryostat_genesis.kv   178       -- If map is inactive, do nothing :
cryostat_genesis.kv   179       if not IsReady(Map) then
cryostat_genesis.kv   180          return;
cryostat_genesis.kv   181       end if;
cryostat_genesis.kv   182       
cryostat_genesis.kv   183       -- If map is writable, sync it to disk :
cryostat_genesis.kv   184       if Map.MapWritable then
cryostat_genesis.kv   185          CErr := MSync(Map.Address, Map.MapLength, MS_SYNC);
cryostat_genesis.kv   186       end if;
cryostat_genesis.kv   187       
cryostat_genesis.kv   188       -- If eggog during MSync() :
cryostat_genesis.kv   189       if CErr /= 0 then
cryostat_genesis.kv   190          Map.Status := Eggog;
cryostat_genesis.kv   191          CErr := Close(Map.FileFD);
cryostat_genesis.kv   192          raise PMapFailedSync with "PMap: Failed to Sync";
cryostat_genesis.kv   193       end if;
cryostat_genesis.kv   194       
cryostat_genesis.kv   195    end Sync;
cryostat_genesis.kv   196    
cryostat_genesis.kv   197    
cryostat_genesis.kv   198    -- Close map and mark it unusable
cryostat_genesis.kv   199    procedure Stop(Map : in out PMap) is
cryostat_genesis.kv   200       
cryostat_genesis.kv   201       -- Result code returned by MUnmap() and Close()
cryostat_genesis.kv   202       CErr : Unix_Int;
cryostat_genesis.kv   203       
cryostat_genesis.kv   204    begin
cryostat_genesis.kv   205       
cryostat_genesis.kv   206       -- If map is already inactive, do nothing :
cryostat_genesis.kv   207       if not IsReady(Map) then
cryostat_genesis.kv   208          return;
cryostat_genesis.kv   209       end if;
cryostat_genesis.kv   210       
cryostat_genesis.kv   211       -- Sync all changes to disk, if map was writable :
cryostat_genesis.kv   212       Sync(Map);
cryostat_genesis.kv   213       
cryostat_genesis.kv   214       -- Mark map as inactive :
cryostat_genesis.kv   215       Map.Status := Stop;
cryostat_genesis.kv   216       
cryostat_genesis.kv   217       -- Unmap the map :
cryostat_genesis.kv   218       CErr := MUnmap(Map.Address, Map.MapLength);
cryostat_genesis.kv   219       if CErr /= 0 then
cryostat_genesis.kv   220          Map.Status := Eggog;
cryostat_genesis.kv   221          raise PMapFailedUnmap with "PMap: Failed to Unmap";
cryostat_genesis.kv   222       end if;
cryostat_genesis.kv   223       
cryostat_genesis.kv   224       -- Lastly, close out the FD :
cryostat_genesis.kv   225       CErr := Close(Map.FileFD);
cryostat_genesis.kv   226       if CErr /= 0 then
cryostat_genesis.kv   227          Map.Status := Eggog;
cryostat_genesis.kv   228          raise PMapFailedClose with "PMap: Failed to Close backing file";
cryostat_genesis.kv   229       end if;
cryostat_genesis.kv   230       
cryostat_genesis.kv   231    end Stop;
cryostat_genesis.kv   232    
cryostat_genesis.kv   233    
cryostat_genesis.kv   234    -- Sync and close a given map, if fell out of scope
cryostat_genesis.kv   235    procedure Finalize(Map : in out PMap) is
cryostat_genesis.kv   236    begin
cryostat_genesis.kv   237       
cryostat_genesis.kv   238       -- Close the map :
cryostat_genesis.kv   239       Stop(Map);
cryostat_genesis.kv   240       
cryostat_genesis.kv   241    end Finalize;
cryostat_genesis.kv   242    
cryostat_genesis.kv   243 end PMaps;