From e78900d0aef21345d04c2cfb1904127ace9dc453 Mon Sep 17 00:00:00 2001
From: Aleteoryx <alyx@aleteoryx.me>
Date: Sun, 23 Feb 2025 22:50:32 -0500
Subject: [PATCH] tar import/export

---
 .gitignore    |   1 +
 backupper.tcl | 207 +++++++++++++++++++++++++++++++++++++++++++++++---
 naivetar.tcl  |  67 ++++++++++++++++
 3 files changed, 263 insertions(+), 12 deletions(-)
 create mode 100644 naivetar.tcl

diff --git a/.gitignore b/.gitignore
index 0a11896adf299181be31eb4e82830cd821b7b5c1..cf300cd9ec407b7775f4dbf55dec82c0494e16a9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 *~
 store/
 *.png
+*.tar
diff --git a/backupper.tcl b/backupper.tcl
index ae786632288f55f531add2c59e1a9e5225e20224..7c698814729dc5289a0c4b7ccfca40a8d98ba677 100755
--- a/backupper.tcl
+++ b/backupper.tcl
@@ -2,6 +2,7 @@
 
 package require sqlite3
 package require Thread
+package require tcl::chan::string
 
 set init {
   package require sha256
@@ -142,14 +143,73 @@ set init {
 }
 eval $init
 
+namespace eval ::tar {}
+proc ::tar::nextrec {fd} {
+  set hdr [read $fd 512]
+  binary scan $hdr c _
+  if {[string length $hdr] != 512} { die "got partial header: [string length $hdr] b" }
+
+  binary scan $hdr a100c24a11c1c12c8a1c* name blind1 size _ blind2 _ type blind3
+  set name [lindex [split $name "\0"] 0]
+
+  if {$name == {}} return
+
+  set data [read $fd [expr {$size}]]
+  if {$size % 512 != 0} {
+    read $fd [expr {512 - ($size % 512)}]
+  }
+
+  return [list name $name type $type data [binary encode hex $data]  blind1 $blind1 blind2 $blind2 blind3 $blind3]
+}
+proc ::tar::fmtrec {rec} {
+  set name [dict get $rec name]
+  set type [dict get $rec type]
+  set size [expr {[string length [dict get $rec data]] / 2}]
+  set size [format %011o $size]
+
+  set blind1 [dict get $rec blind1]
+  set blind2 [dict get $rec blind2]
+  set blind3 [dict get $rec blind3]
+
+  set hdr [binary format a100c24a12c12A8a1c* $name $blind1 $size $blind2 "" $type $blind3]
+  binary scan $hdr c* bytes
+  set checksum 0
+  foreach byte $bytes {
+    incr checksum [expr {$byte & 0xFF}]
+  }
+  set checksum [format %07o $checksum]
+  set hdr [binary format a100c24a12c12a8a1c* $name $blind1 $size $blind2 $checksum $type $blind3]
+
+  append hdr [binary decode hex [dict get $rec data]]
+  if {$size % 512 != 0} {
+    append hdr [binary format a[expr {512 - ($size % 512)}] ""]
+  }
+
+  return $hdr
+}
+
+
 proc usage {} {
   global argv0
-  puts stderr "usage: $argv0 command store ?args ...?"
-  puts stderr "commands:"
-  puts stderr "  init - initialize a store in store"
-  puts stderr "  importlist ?listfile? - if listfile is ommitted, reads stdin"
-  puts stderr "  print hash - prints the contents of <hash> on stdout"
-  puts stderr "  stat hash - prints metadata about <hash>"
+  puts stderr {usage: $argv0 command store ?args ...?
+commands:
+  init
+    - initialize a store in store
+  importlist name ?listfile?
+    - imports the contents of listfile under name, treating each line as a filepath
+    - if listfile is ommitted, reads stdin
+  importtar name ?tarfile?
+    - imports the contents of tarfile under name. will not auto-decompress.
+    - if tarfile is ommitted, reads stdin
+  import ?filepath?
+    - stores the contents of filepath, returning the hash
+    - if filepath is ommitted, reads stdin
+  export id
+    - exports the contents of backup id to a file named like NAME_DATE
+  print hash
+    - prints the contents of the file named by hash on stdout
+  stat hash
+    - prints metadata about the file named by hash}
   exit -1
 }
 proc die {reason} {
@@ -186,13 +246,13 @@ set pool [tpool::create -maxworkers $nproc -initcmd [concat $init "; " [list set
 
 switch -- $command {
   importlist {
-    if {[llength $argv] > 1} usage
-    if {[llength $argv] == 1} {
-      set fd [open [lindex $argv 0]]
-      set fname [lindex $argv 0]
+    if {[llength $argv] ni {1 2}} usage
+    set fname [lindex $argv 0]
+
+    if {[llength $argv] == 2} {
+      set fd [open [lindex $argv 1]]
     } else {
       set fd stdin
-      set fname "pipeline"
     }
 
     set files [split [string trim [read $fd]] "\n"]
@@ -212,7 +272,7 @@ switch -- $command {
         close $fd
 
         set hash [writestore $arpath $data 1]
-        return [list [string trimleft $filename "/"] $hash]
+        return [list [string trimleft [file normalize $filename] "/"] $hash]
       }]
 
       lappend joblist [tpool::post $pool $script]
@@ -234,6 +294,115 @@ switch -- $command {
     puts stderr "inserted as archive $rowid with hash $ref"
   }
 
+  importtar {
+    if {[llength $argv] ni {1 2}} usage
+    set fname [lindex $argv 0]
+
+    if {[llength $argv] == 2} {
+      set fd [open [lindex $argv 1]] rb
+    } else {
+      set fd stdin
+      fconfigure stdin -translation binary
+    }
+
+    set joblist {}
+    set result {}
+
+    while {[set record [::tar::nextrec $fd]] != {}} {
+      set script [concat [list set record $record] "; " {
+        set hash [writestore $arpath [binary decode hex [dict get $record data]] 1]
+        dict set record data $hash
+        return $record
+      }]
+
+      lappend joblist [tpool::post $pool $script]
+    }
+
+    if {$fd != "stdin"} { close $fd }
+
+    foreach job $joblist {
+      tpool::wait $pool $job
+      append result [::tar::fmtrec [tpool::get $pool $job]]
+    }
+
+    append result [binary format a[expr {16384 - ([string length $result] % 16384) + 512}] ""]
+
+    set ref [writestore $arpath $result 1]
+    set date [clock seconds]
+    set rowid [db eval {
+      INSERT INTO tarballs VALUES ($fname, "tar", $ref, "", $date) RETURNING rowid;
+    }]
+
+    puts stderr "inserted as archive $rowid with hash $ref"
+  }
+
+  export {
+    if {[llength $argv] != 1} usage
+
+    set rowid [lindex $argv 0]
+    set record [db eval {
+      SELECT ref,type,name,date FROM tarballs WHERE rowid = $rowid;
+    }]
+    if {[llength $record] == 0} { die "unknown archive id" }
+    lassign $record ref type name date
+
+    set exportname [regsub "/" "${name}_[clock format $date -format {%Y-%m-%d_%H.%M.%S}]" "-"]
+    set archive [readstore $arpath $ref 1]
+
+    switch -- $type {
+      list {
+        file mkdir $exportname
+
+        set joblist {}
+        foreach {path hash} $archive {
+          set script [concat [list set path "$exportname/$path"] "; " [list set hash $hash] "; " {
+            puts "$hash -> $path"
+            file mkdir [file dirname $path]
+            set fd [open "$path" wb]
+            puts -nonewline $fd [readstore $arpath $hash 1]
+            close $fd
+          }]
+
+          lappend joblist [tpool::post $pool $script]
+        }
+
+        foreach job $joblist {
+          tpool::wait $pool $job
+        }
+      }
+      tar {
+        set exportname "$exportname.tar"
+        set exportfd [open $exportname wb]
+
+        set importfd [::tcl::chan::string $archive]
+        fconfigure $importfd -translation binary
+
+        set joblist {}
+        while {[set record [::tar::nextrec $importfd]] != {}} {
+          set script [concat [list set record $record] "; " {
+            dict set record data [binary encode hex [readstore $arpath [dict get $record data] 1]]
+            return $record
+          }]
+
+          lappend joblist [tpool::post -nowait $pool $script]
+        }
+
+        foreach job $joblist {
+          tpool::wait $pool $job
+          puts -nonewline $exportfd [::tar::fmtrec [tpool::get $pool $job]]
+        }
+        puts -nonewline $exportfd [binary format a[expr {16384 - ([tell $exportfd] % 16384) + 512}] ""]
+
+        close $exportfd
+      }
+      default {
+        die "database corrupt: unknown archive type \"$type\""
+      }
+    }
+
+    puts "exported to $exportname"
+  }
+
   print {
     if {[llength $argv] != 1} usage
 
@@ -257,5 +426,19 @@ switch -- $command {
     puts "  data size (bytes): [dict get $stat datasize]"
   }
 
+  import {
+    if {[llength $argv] > 1} usage
+    if {[llength $argv] == 1} {
+      set fd [open [lindex $argv 0]]
+    } else {
+      set fd stdin
+    }
+
+    set data [read $fd]
+
+    set hash [writestore $arpath $data 1]
+    puts "imported as $hash"
+  }
+
   default usage
 }
diff --git a/naivetar.tcl b/naivetar.tcl
new file mode 100644
index 0000000000000000000000000000000000000000..4114748e142c2484841bd157347462b91ddd99c8
--- /dev/null
+++ b/naivetar.tcl
@@ -0,0 +1,67 @@
+
+proc die {reason} {
+  global argv0
+  puts stderr "$argv0: fatal: $reason"
+  exit -2
+}
+
+proc nextrec {fd} {
+  set hdr [read $fd 512]
+  binary scan $hdr c _
+  if {[string length $hdr] != 512} { die "got partial header: [string length $hdr]b" }
+
+  binary scan $hdr a100c24a11c1c12c8a1c* name blind1 size _ blind2 _ type blind3
+  set name [lindex [split $name "\0"] 0]
+
+  if {$name == {}} return
+
+  set data [read $fd [expr {$size}]]
+  if {$size % 512 != 0} {
+    read $fd [expr {512 - ($size % 512)}]
+  }
+
+  return [list name $name type $type data [binary encode hex $data]  blind1 $blind1 blind2 $blind2 blind3 $blind3]
+}
+
+proc putrec {fd rec} {
+  set name [dict get $rec name]
+  set type [dict get $rec type]
+  set size [expr {[string length [dict get $rec data]] / 2}]
+  set size [format %011o $size]
+
+#  puts "$name - $size"
+
+  set blind1 [dict get $rec blind1]
+  set blind2 [dict get $rec blind2]
+  set blind3 [dict get $rec blind3]
+
+  set hdr [binary format a100c24a12c12A8a1c* $name $blind1 $size $blind2 "" $type $blind3]
+  binary scan $hdr c* bytes
+  set checksum 0
+  foreach byte $bytes {
+    incr checksum [expr {$byte & 0xFF}]
+  }
+  set checksum [format %07o $checksum]
+  set hdr [binary format a100c24a12c12a8a1c* $name $blind1 $size $blind2 $checksum $type $blind3]
+
+  puts -nonewline $fd $hdr
+
+  puts -nonewline $fd [binary decode hex [dict get $rec data]]
+  if {$size % 512 != 0} {
+    puts -nonewline $fd [binary format a[expr {512 - ($size % 512)}] ""]
+  }
+}
+
+set fd [open [lindex $argv 0] rb]
+set fd2 [open [lindex $argv 1] wb]
+
+while {[set record [nextrec $fd]] != {}} {
+  if {[dict get $record type] == "0"} {
+    puts "type of [dict get $record name] is 0, overwriting"
+    dict set record data [binary encode hex "Hello, World!"]
+#    puts $record
+  }
+  putrec $fd2 $record
+}
+
+puts -nonewline $fd2 [binary format a[expr {16384 - ([tell $fd2] % 16384)}] ""]