From 5088d7147c905bb10872e360c1aaf2dab6d618c7 Mon Sep 17 00:00:00 2001
From: Miles Bader <miles@gnu.org>
Date: Sat, 10 Aug 1996 20:13:02 +0000
Subject: *** empty log message ***

---
 sutils/e2os.sh | 143 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100755 sutils/e2os.sh

diff --git a/sutils/e2os.sh b/sutils/e2os.sh
new file mode 100755
index 00000000..028f076e
--- /dev/null
+++ b/sutils/e2os.sh
@@ -0,0 +1,143 @@
+#!/bin/sh
+# Set/get the `creator_os' field of an ext2fs partition
+#
+# Copyright (C) 1996 Free Software Foundation, Inc.
+#
+# Written by Miles Bader <miles@gnu.ai.mit.edu>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+#
+
+DD=/bin/dd
+OD=/bin/od
+SED=/bin/sed
+AWK=/bin/gawk
+
+USAGE="Usage: $0 DEVICE [OS]"
+
+while :; do
+  case "$1" in
+    --help|"-?")
+      echo "$USAGE"
+      echo "Get or set the creator_os parameter of an ext2fs partition."
+      echo ""
+      echo "  -?, --help                 Give this help list"
+      echo "      --usage                Give a short usage message"
+      echo "  -V, --version              Print program version"
+      exit 0;;
+    --usage)
+      echo "Usage: $0 [-V?] [--help] [--usage] [--version] DEVICE [OS]"
+      exit 0;;
+    --version|-V)
+      echo "e2os 1.0 (`uname -sr`)"; exit 0;;
+    -*)
+      echo 1>&2 "$0: unrecognized option \`$1'"
+      echo 1>&2 "Try \`$0 --help' for more information";
+      exit 1;;
+    *)
+      break;;
+  esac
+done
+
+case  "$#" in 1 | 2) ;; # ok
+  *) echo 1>&2 "$USAGE"
+     echo 1>&2 "Try \`--help' for more information";
+     exit 1;;
+esac
+
+DEVICE="$1"; shift
+OS="$1"
+
+# Superblock fields (format is "BYTE_OFFS SIZE")
+SB_MAGIC="56 2"
+SB_OS="72 4"
+# Ext2fs magic numbers
+MAGIC_EXT2=ef53
+MAGIC_EXT2_OLD=ef53
+# Symbolic names for os types we know about
+OS_LINUX=0
+OS_HURD=1
+OS_MASIX=2
+
+# Superblock
+SB=/tmp/,e2os-sb.$$
+
+# We have to store error output in a file so that we can filter it (for all
+# unix's stressing of pipelines, /bin/sh sure works hard to prevent you using
+# them).
+ERRS=/tmp/,e2os-errs.$$
+
+trap "/bin/rm -f $SB $ERRS" 0
+
+# Read the superblock
+$DD 2>"$ERRS" if="$DEVICE" of="$SB" bs=1k skip=1 count=1 \
+|| { $SED 1>&2 "s;^$DD:;$0:;" "$ERRS"; exit 2 }
+
+# Extract a word of SZ bytes from byte offset POS in the superblock
+# Optional arg FMT is what format to use (x = hex, d = decimal)
+function sbget
+{
+  local pos="$1" sz="$2" fmt="${3-d}"
+  pos=$(($pos / $sz))
+  $DD 2>/dev/null if="$SB" bs="$sz" skip="$pos" count=1 \
+  | $OD -An -t"$fmt$sz" \
+  | $SED 's;^[ 0]*\(.\);\1;'
+}
+
+# Set a word of SZ bytes at byte offset POS in the superblock to VAL
+function sbset
+{
+  local pos="$1" sz="$2" val="$3"
+  pos=$(($pos / $sz))
+  echo "$val" \
+  | $AWK '{ n=$1+0; printf ("%c%c%c%c", n, n/256, n/(2^16), n/(2^24)); }' \
+  | $DD 2>/dev/null of="$SB" bs="$sz" seek="$pos" count=1 conv=notrunc
+}
+
+# Check the magic number
+magic="`sbget $SB_MAGIC x`"
+case "$magic" in
+  $MAGIC_EXT2)     ;; # ok
+  $MAGIC_EXT2_OLD) echo "$0: $DEVICE: Old-format ext2 filesystem"; exit 3;;
+  *) echo "$0: $DEVICE: Not an ext2 filesystem (magic = 0x$magic)"; exit 4;;
+esac
+
+if test "$OS"; then
+  # Set the os field
+  case "$OS" in
+    linux) OS=$OS_LINUX;;
+    hurd)  OS=$OS_HURD;;
+    masix) OS=$OS_MASIX;;
+    "*[!0-9]*") 
+      echo 1>&2 "$0: $OS: Unknown ext2 creator_os value"; exit 5;;
+  esac
+
+  # Frob the superlock
+  sbset $SB_OS "$OS"
+
+  # Write the superblock
+  $DD 2>"$ERRS" if="$SB" of="$DEVICE" bs=1k seek=1 count=1 \
+  || { $SED 1>&2 "s;^$DD:;$0:;" "$ERRS"; exit 6 }
+else
+  # Print the os field.
+  OS="`sbget $SB_OS`"
+  case "$OS" in
+    "") exit 2;;
+    $OS_LINUX) OS=linux;;
+    $OS_HURD)  OS=hurd;;
+    $OS_MASIX) OS=masix;;
+  esac
+  echo "$OS"
+fi
-- 
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