On Sat, Dec 22, 2012 at 20:43:16 -0800, Paul Eggert wrote:
> * src/incremen.c (read_incr_db_01, write_directory_file_entry):
> Allow negative time_t, dev_t, and ino_t.
Attached is a patch to the tar-snapshot-edit script to:
* support architecture-specific field ranges for the "-c" function
* better handle negative or larger-than-32-bit field values even
when running in 32-bit Perl (for the default "print a summary"
function)
Nathan
----------------------------------------------------------------------------
Nathan Stratton Treadway - natha...@ontko.com - Mid-Atlantic region
Ray Ontko & Co. - Software consulting services - http://www.ontko.com/
GPG Key: http://www.ontko.com/~nathanst/gpg_key.txt ID: 1023D/ECFB6239
Key fingerprint = 6AD8 485E 20B9 5C71 231C 0C32 15F3 ADCD ECFB 6239
--- fromgit/tar-snapshot-edit 2012-12-31 16:46:54.778362426 -0500
+++ ./tar-snapshot-edit 2013-03-13 10:45:18.993913482 -0400
@@ -28,7 +28,8 @@
#
# It can also run a check on all the field values found in the
# snapshot file, printing out a detailed message when it finds values
-# that would cause an "Unexpected field value in snapshot file" error
+# that would cause an "Unexpected field value in snapshot file",
+# "Numerical result out of range", or "Invalid argument" error
# if tar were run using that snapshot file as input. (See the
# comments included in the definition of the check_field_values
# routine for more detailed information regarding these checks.)
@@ -47,9 +48,19 @@
# or 2 files.
# * tweak output formatting
#
-#
+# Modified March 13, 2013 by Nathan Stratton Treadway <nathanst AT ontko.com>:
+# * configure field ranges used for -c option based on the system
+# architecture (in response to the December 2012 update to GNU tar
+# enabling support for systems with signed dev_t values).
+# * when printing the list of device ids found in the snapshot file
+# (when run in the default mode), print the raw device id values
+# instead of the hex-string version in those cases where they
+# can't be converted successfully.
use Getopt::Std;
+use Config;
+
+my %snapshot_field_ranges; # used in check_field_values function
## reading
@@ -207,30 +218,151 @@
$devices{$dev}++;
}
+ my $devstr;
foreach $dev (sort {$a <=> $b} keys %devices) {
- printf " Device 0x%04x occurs $devices{$dev} times.\n", $dev;
+ $devstr = sprintf ("0x%04x", $dev);
+ if ( $dev > 0xffffffff or $dev < 0 or hex($devstr) != $dev ) {
+ # sprintf "%x" will not return a useful value for device ids
+ # that are negative or which overflow the integer size on this
+ # instance of Perl, so we convert the hex string back to a
+ # number, and if it doesn't (numerically) equal the original
+ # device id value, we know the hex conversion hasn't worked.
+ #
+ # Unfortunately, since we're running in "-w" mode, Perl will
+ # also print a warning message if the hex() routine is called
+ # on anything larger than "0xffffffff", even in 64-bit Perl
+ # where such values are actually supported... so we have to
+ # avoid calling hex() at all if the device id is too large or
+ # negative. (If it's negative, the conversion to an unsigned
+ # integer for the "%x" specifier will mean the result will
+ # always trigger hex()'s warning on a 64-bit machine.)
+ #
+ # These situations don't seem to occur very often, so for now
+ # when they do occur, we simply print the original text value
+ # that was read from the snapshot file; it will look a bit
+ # funny next to the values that do print in hex, but that's
+ # preferable to printing values that aren't actually correct.
+ $devstr = $dev;
+ }
+ printf " Device %s occurs $devices{$dev} times.\n", $devstr;
}
}
## check field values
-# returns a warning message if $field isn't a valid string representation
-# of an integer, or if the resulting integer is out of the specified range
-sub validate_integer_field ($$$$) {
- my $field = shift;
+# initializes the global %snapshot_field_ranges hash, based on the "-a"
+# command-line option if given, otherwise based on the "archname" of
+# the current system.
+#
+# Each value in the hash is a two-element array containing the minimum
+# and maximum allowed values, respectively, for that field in the snapshot
+# file. GNU tar's allowed values for each architecture are determined
+# in the incremen.c source file, where the TYPE_MIN and TYPE_MAX
+# pre-processor expressions are used to determine the range that can be
+# expressed by the C data type used for each field; the values in the
+# array defined below should match those calculations.
+
+sub choose_architecture ($) {
+ my $opt_a = shift;
+
+ my $arch = $opt_a ? $opt_a : $Config{'archname'};
+
+ # These ranges apply to Linux 2.4/2.6 on iX86 systems, but are used
+ # by default on unrecognized/unsupported systems, too.
+ %iX86_linux_field_ranges = (
+ timestamp_sec => [ -2147483648, 2147483647 ], # min/max of time_t
+ timestamp_nsec => [ 0, 999999999 ], # 0 to BILLION-1
+ nfs => [ 0, 1 ],
+ dev => [ 0, 18446744073709551615 ], # min/max of dev_t
+ ino => [ 0, 4294967295 ], # min/max of ino_t
+ );
+
+
+ if ( $arch =~ m/^i[\dxX]86-linux/i ) {
+ %snapshot_field_ranges = %iX86_linux_field_ranges;
+ print "Checking snapshot field values using \"iX86-linux\" ranges.\n\n";
+ } elsif ( $arch =~ m/^x86_64-linux/i ) {
+ %snapshot_field_ranges = (
+ timestamp_sec => [ -9223372036854775808, 9223372036854775807 ],
+ timestamp_nsec => [ 0, 999999999 ],
+ nfs => [ 0, 1 ],
+ dev => [ 0, 18446744073709551615 ],
+ ino => [ 0, 18446744073709551615 ],
+ );
+ print "Checking snapshot field values using \"x86_64-linux\" ranges.\n\n";
+ } elsif ( $arch =~ m/^IA64.ARCHREV_0/i ) {
+ # HP/UX running on Itanium/ia64 architecture
+ %snapshot_field_ranges = (
+ timestamp_sec => [ -2147483648, 2147483647 ],
+ timestamp_nsec => [ 0, 999999999 ],
+ nfs => [ 0, 1 ],
+ dev => [ -2147483648, 2147483647 ],
+ ino => [ 0, 4294967295 ],
+ );
+ print "Checking snapshot field values using \"IA64.ARCHREV_0\" (HP/UX) ranges.\n\n";
+ } else {
+ %snapshot_field_ranges = %iX86_linux_field_ranges;
+ print "Unrecognized architecture \"$arch\"; defaulting to \"iX86-linux\".\n";
+ print "(Use -a option to override.)\n" unless $opt_a;
+ print "\n";
+ }
+
+ if ( ref(1) ne "" ) {
+ print "(\"bignum\" mode is in effect; skipping 64-bit-integer check.)\n\n"
+ } else {
+ # find the largest max value in the current set of ranges
+ my $maxmax = 0;
+ for $v (values %snapshot_field_ranges ) {
+ $maxmax = $v->[1] if ($v->[1] > $maxmax);
+ }
+
+ # "~0" translates into a platform-native integer with all bits turned
+ # on -- that is, the largest value that can be represented as
+ # an integer. We print a warning if our $maxmax value is greater
+ # than that largest integer, since in that case Perl will switch
+ # to using floats for those large max values. The wording of
+ # the message assumes that the only way this situation can exist
+ # is that the platform uses 32-bit integers but some of the
+ # snapshot-file fields have 64-bit values.
+ if ( ~0 < $maxmax ) {
+ print <<EOF
+Note: this version of Perl uses 32-bit integers, which means that it
+ will switch to using floating-point numbers when checking the ranges
+ for 64-bit snapshot-file fields. This normally will work fine, but
+ might fail to detect cases where the value in the input field value is
+ only slightly out of range. (For example, a "9223372036854775808"
+ might not be recognized as being larger than 9223372036854775807.)
+ If you suspect you are experiencing this problem, you can try running
+ the program using the "-Mbignum" option, as in
+ \$ perl $0 -Mbignum -c [FILES]
+ (but doing so will make the program run *much* slower).
+
+EOF
+ }
+ }
+
+
+}
+
+# returns a warning message if $field_value isn't a valid string
+# representation of an integer, or if the resulting integer is out of range
+# defined by the two-element array retrieved using up the $field_name key in
+# the global %snapshot_field_ranges hash.
+sub validate_integer_field ($$) {
+ my $field_value = shift;
my $field_name = shift;
- my $min = shift;
- my $max = shift;
+
+ my ($min, $max) = @{$snapshot_field_ranges{$field_name}};
my $msg = "";
- if ( not $field =~ /^-?\d+$/ ) {
- $msg = " $field_name value contains invalid characters: \"$field\"\n";
+ if ( not $field_value =~ /^-?\d+$/ ) {
+ $msg = " $field_name value contains invalid characters: \"$field_value\"\n";
} else {
- if ( $field < $min ) {
- $msg = " $field_name value too low: \"$field\" < $min \n";
- } elsif ( $field > $max ) {
- $msg = " $field_name value too high: \"$field\" > $max \n";
+ if ( $field_value < $min ) {
+ $msg = " $field_name value too low: \"$field_value\" < $min \n";
+ } elsif ( $field_value > $max ) {
+ $msg = " $field_name value too high: \"$field_value\" > $max \n";
}
}
return $msg;
@@ -239,28 +371,18 @@
# This routine loops through each directory entry in the $info data
# structure and prints a warning message if tar would abort with an
-# "Unexpected field value in snapshot file" error upon reading this
-# snapshot file.
+# "Unexpected field value in snapshot file", "Numerical result out of
+# range", or "Invalid argument" error upon reading this snapshot file.
#
-# (Note that this specific error message was introduced along with the
-# change to snapshot file format "2", starting with tar v1.16 [or,
-# more precisely, v1.15.91].)
+# (Note that the "Unexpected field value in snapshot file" error message
+# was introduced along with the change to snapshot file format "2",
+# starting with tar v1.16 [or, more precisely, v1.15.91], while the
+# other two were introduced in v1.27.)
#
# The checks here are intended to match those found in the incremen.c
-# source file (as of tar v1.16.1).
-#
-# In that code, the checks are done against pre-processor expressions,
-# as defined in the C header files at compile time. In the routine
-# below, a Perl variable is created for each expression used as part of
-# one of these checks, assigned the value of the related pre-processor
-# expression as found on a Linux 2.6.8/i386 system.
-#
-# It seems likely that these settings will catch most invalid
-# field values found in actual snapshot files on all systems. However,
-# if "tar" is erroring out on a snapshot file that this check routine
-# does not complain about, that probably indicates that the values
-# below need to be adjusted to match those used by "tar" in that
-# particular environment.
+# source file. See the choose_architecture() function (above) for more
+# information on how to configure the range of values considered valid
+# by this script.
#
# (Note: the checks here are taken from the code that processes
# version 2 snapshot files, but to keep things simple we apply those
@@ -270,16 +392,6 @@
sub check_field_values ($) {
my $info = shift;
- # set up a variable with the value of each pre-processor
- # expression used for field-value checks in incremen.c
- # (these values here are from a Linux 2.6.8/i386 system)
- my $BILLION = 1000000000; # BILLION
- my $MIN_TIME_T = -2147483648; # TYPE_MINIMUM(time_t)
- my $MAX_TIME_T = 2147483647; # TYPE_MAXIUMUM(time_t)
- my $MAX_DEV_T = 4294967295; # TYPE_MAXIUMUM(dev_t)
- my $MAX_INO_T = 4294967295; # TYPE_MAXIUMUM(ino_t)
-
-
my $msg;
my $error_found = 0;
@@ -288,11 +400,9 @@
$snapver = $info->[0];
$msg = "";
- $msg .= validate_integer_field($info->[1],
- 'timestamp_sec', $MIN_TIME_T, $MAX_TIME_T);
+ $msg .= validate_integer_field($info->[1], 'timestamp_sec');
if ($snapver >= 1) {
- $msg .= validate_integer_field($info->[2],
- 'timestamp_nsec', 0, $BILLION-1);
+ $msg .= validate_integer_field($info->[2], 'timestamp_nsec');
}
if ( $msg ne "" ) {
$error_found = 1;
@@ -305,15 +415,13 @@
$msg = "";
- $msg .= validate_integer_field($dir->{'nfs'}, 'nfs', 0, 1);
+ $msg .= validate_integer_field($dir->{'nfs'}, 'nfs');
if ($snapver >= 1) {
- $msg .= validate_integer_field($dir->{'timestamp_sec'},
- 'timestamp_sec', $MIN_TIME_T, $MAX_TIME_T);
- $msg .= validate_integer_field($dir->{'timestamp_nsec'},
- 'timestamp_nsec', 0, $BILLION-1);
+ $msg .= validate_integer_field($dir->{'timestamp_sec'}, 'timestamp_sec');
+ $msg .= validate_integer_field($dir->{'timestamp_nsec'}, 'timestamp_nsec');
}
- $msg .= validate_integer_field($dir->{'dev'}, 'dev', 0, $MAX_DEV_T);
- $msg .= validate_integer_field($dir->{'ino'}, 'ino', 0, $MAX_INO_T);
+ $msg .= validate_integer_field($dir->{'dev'}, 'dev');
+ $msg .= validate_integer_field($dir->{'ino'}, 'ino');
if ( $msg ne "" ) {
$error_found = 1;
@@ -438,10 +546,10 @@
## main
sub main {
- our ($opt_b, $opt_r, $opt_h, $opt_c);
- getopts('br:hc');
+ our ($opt_b, $opt_r, $opt_h, $opt_c, $opt_a);
+ getopts('br:hca:');
HELP_MESSAGE() if ($opt_h || $#ARGV == -1 || ($opt_b && !$opt_r) ||
- ($opt_r && $opt_c) );
+ ($opt_a && !$opt_c) || ($opt_r && $opt_c) );
my @repl;
if ($opt_r) {
@@ -451,9 +559,11 @@
}
}
+ choose_architecture($opt_a) if ($opt_c);
+
foreach my $snapfile (@ARGV) {
my $info = read_incr_db($snapfile);
- if ($opt_r ) {
+ if ($opt_r) {
if ($opt_b) {
rename($snapfile, $snapfile . "~") || die "Could not rename '$snapfile' to backup";
}
@@ -474,7 +584,7 @@
Usage:
tar-snapshot-edit SNAPFILE [SNAPFILE [...]]
tar-snapshot-edit -r 'DEV1-DEV2[,DEV3-DEV4...]' [-b] SNAPFILE [SNAPFILE [...]]
- tar-snapshot-edit -c SNAPFILE [SNAPFILE [...]]
+ tar-snapshot-edit -c [-aARCH] SNAPFILE [SNAPFILE [...]]
With no options specified: print a summary of the 'device' values
found in each SNAPFILE.
@@ -487,9 +597,21 @@
With -c: Check the field values in each SNAPFILE and print warning
messages if any invalid values are found. (An invalid value is one
- that would cause \"tar\" to generate an
- Unexpected field value in snapshot file
- error message as it processed the snapshot file.)
+ that would cause \"tar\" to abort with an error message such as
+ Unexpected field value in snapshot file
+ Numerical result out of range
+ or
+ Invalid argument
+ as it processed the snapshot file.)
+
+ Normally the program automatically chooses the valid ranges for
+ the fields based on the current system's architecture, but the
+ -a option can be used to override the selection, e.g. in order
+ to validate a snapshot file generated on a some other system.
+ (Currently only three architectures are supported, "iX86-linux",
+ "x86_64-linux", and "IA64.ARCHREV_0" [HP/UX running on Itanium/ia64],
+ and if the current system isn't recognized, then the iX86-linux
+ values are used by default.)
EOF
exit 1;
