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@@ -1,4 +1,4 @@
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-.\" $File: magic.man,v 1.36 2007/01/10 22:56:49 christos Exp $
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+.\" $File: magic.man,v 1.38 2007/01/27 00:52:08 ljt Exp $
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.Dd January 10, 2007
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.Dt MAGIC __FSECTION__
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.Os
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@@ -49,7 +49,7 @@ An eight-byte value (on most systems) in this machine's native byte order.
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A string of bytes.
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The string type specification can be optionally followed
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by /[Bbc]*.
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-The
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+The
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.Dq B
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flag compacts whitespace in the target, which must
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contain at least one whitespace character.
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@@ -58,7 +58,7 @@ If the magic has
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consecutive blanks, the target needs at least
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.Dv n
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consecutive blanks to match.
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-The
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+The
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.Dq b
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flag treats every blank in the target as an optional blank.
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Finally the
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@@ -69,7 +69,8 @@ targer, whereas upper case characters in the magic, only much uppercase
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characters in the target.
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.It Dv pstring
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A pascal style string where the first byte is interpreted as the an
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-unsigned length. The string is not NUL terminated.
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+unsigned length.
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+The string is not NUL terminated.
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.It Dv date
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A four-byte value interpreted as a UNIX date.
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.It Dv qdate
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@@ -137,7 +138,7 @@ than UTC.
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A regular expression match in extended POSIX regular expression syntax
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(much like egrep).
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The type specification can be optionally followed by /[cse]*.
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-The
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+The
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.Dq c
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flag makes the match case insensitive, while the
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.Dq s
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@@ -158,14 +159,15 @@ and
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will match the beginning and end of individual lines, respectively,
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not beginning and end of file.
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.It Dv search
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-A literal string search starting at the given offset. It must be followed by
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-.Dv /<number>
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+A literal string search starting at the given offset.
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+It must be followed by
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+.Dv \*[Lt]number\*[Gt]
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which specifies how many matches shall be attempted (the range).
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This is suitable for searching larger binary expressions with variable
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offsets, using
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.Dv \e
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escapes for special characters.
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-.It Dv default
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+.It Dv default
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This is intended to be used with the text
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.Dv x
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(which is always true) and a message that is to be used if there are
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@@ -174,7 +176,7 @@ no other matches.
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.El
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.Pp
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The numeric types may optionally be followed by
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-.Dv &
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+.Dv \*[Am]
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and a numeric value,
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to specify that the value is to be AND'ed with the
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numeric value before any comparisons are done.
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@@ -194,13 +196,13 @@ may be preceded by a character indicating the operation to be performed.
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It may be
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.Dv = ,
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to specify that the value from the file must equal the specified value,
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-.Dv < ,
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+.Dv \*[Lt] ,
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to specify that the value from the file must be less than the specified
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value,
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-.Dv > ,
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+.Dv \*[Gt] ,
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to specify that the value from the file must be greater than the specified
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value,
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-.Dv & ,
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+.Dv \*[Am] ,
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to specify that the value from the file must have set all of the bits
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that are set in the specified value,
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.Dv ^ ,
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@@ -215,7 +217,7 @@ If the character is omitted, it is assumed to be
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For all tests except
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.Em string
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and
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-.Em regex,
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+.Em regex ,
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operation
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.Dv !
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specifies that the line matches if the test does
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@@ -234,25 +236,25 @@ For string values, the byte string from the
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file must match the specified byte string.
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The operators
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.Dv = ,
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-.Dv <
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+.Dv \*[Lt]
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and
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-.Dv >
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+.Dv \*[Gt]
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(but not
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-.Dv & )
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+.Dv \*[Am] )
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can be applied to strings.
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The length used for matching is that of the string argument
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in the magic file.
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This means that a line can match any string, and
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then presumably print that string, by doing
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-.Em >\e0
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+.Em \*[Gt]\e0
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(because all strings are greater than the null string).
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.Pp
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The special test
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.Em x
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always evaluates to true.
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.Dv message
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-The message to be printed if the comparison succeeds. If the string
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-contains a
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+The message to be printed if the comparison succeeds.
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+If the string contains a
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.Xr printf 3
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format specification, the value from the file (with any specified masking
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performed) is printed using the message as the format string.
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@@ -265,12 +267,12 @@ Some file formats contain additional information which is to be printed
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along with the file type or need additional tests to determine the true
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file type.
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These additional tests are introduced by one or more
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-.Em >
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+.Em \*[Gt]
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characters preceding the offset.
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The number of
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-.Em >
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+.Em \*[Gt]
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on the line indicates the level of the test; a line with no
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-.Em >
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+.Em \*[Gt]
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at the beginning is considered to be at level 0.
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Tests are arranged in a tree-like hierarchy:
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If a the test on a line at level
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@@ -283,16 +285,16 @@ with level
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(or less) appears.
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For more complex files, one can use empty messages to get just the
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"if/then" effect, in the following way:
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-.Bd -literal -offset indent
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+.Bd -literal -offset indent
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0 string MZ
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->0x18 leshort <0x40 MS-DOS executable
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->0x18 leshort >0x3f extended PC executable (e.g., MS Windows)
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+\*[Gt]0x18 leshort \*[Lt]0x40 MS-DOS executable
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+\*[Gt]0x18 leshort \*[Gt]0x3f extended PC executable (e.g., MS Windows)
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.Ed
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.Pp
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Offsets do not need to be constant, but can also be read from the file
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being examined.
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If the first character following the last
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-.Em >
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+.Em \*[Gt]
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is a
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.Em (
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then the string after the parenthesis is interpreted as an indirect offset.
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@@ -301,11 +303,11 @@ the file.
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The value at that offset is read, and is used again as an offset
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in the file.
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Indirect offsets are of the form:
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-.Em (( x [.[bslBSL]][+\-][ y ]).
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+.Em (( x [.[bslBSL]][+\-][ y ]) .
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The value of
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.Em x
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-is used as an offset in the file. A byte, short or long is read at that offset
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-depending on the
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+is used as an offset in the file.
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+A byte, short or long is read at that offset depending on the
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.Em [bslBSLm]
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type specifier.
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The capitalized types interpret the number as a big endian
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@@ -320,14 +322,14 @@ is added and the result is used as an offset in the file.
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The default type if one is not specified is long.
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.Pp
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That way variable length structures can be examined:
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-.Bd -literal -offset indent
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+.Bd -literal -offset indent
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# MS Windows executables are also valid MS-DOS executables
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0 string MZ
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->0x18 leshort <0x40 MZ executable (MS-DOS)
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+\*[Gt]0x18 leshort \*[Lt]0x40 MZ executable (MS-DOS)
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# skip the whole block below if it is not an extended executable
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->0x18 leshort >0x3f
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->>(0x3c.l) string PE\e0\e0 PE executable (MS-Windows)
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->>(0x3c.l) string LX\e0\e0 LX executable (OS/2)
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+\*[Gt]0x18 leshort \*[Gt]0x3f
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+\*[Gt]\*[Gt](0x3c.l) string PE\e0\e0 PE executable (MS-Windows)
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+\*[Gt]\*[Gt](0x3c.l) string LX\e0\e0 LX executable (OS/2)
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.Ed
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.Pp
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This strategy of examining has one drawback: You must make sure that
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@@ -336,79 +338,84 @@ there is neither PE\e0\e0 nor LE\e0\e0 in the above example)
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.Pp
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If this indirect offset cannot be used as-is, there are simple calculations
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possible: appending
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-.Em [+-*/%&|^]<number>
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+.Em [+-*/%\*[Am]|^]\*[Lt]number\*[Gt]
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inside parentheses allows one to modify
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the value read from the file before it is used as an offset:
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-.Bd -literal -offset indent
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+.Bd -literal -offset indent
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# MS Windows executables are also valid MS-DOS executables
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0 string MZ
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# sometimes, the value at 0x18 is less that 0x40 but there's still an
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# extended executable, simply appended to the file
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->0x18 leshort <0x40
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->>(4.s*512) leshort 0x014c COFF executable (MS-DOS, DJGPP)
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->>(4.s*512) leshort !0x014c MZ executable (MS-DOS)
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+\*[Gt]0x18 leshort \*[Lt]0x40
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+\*[Gt]\*[Gt](4.s*512) leshort 0x014c COFF executable (MS-DOS, DJGPP)
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+\*[Gt]\*[Gt](4.s*512) leshort !0x014c MZ executable (MS-DOS)
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.Ed
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.Pp
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Sometimes you do not know the exact offset as this depends on the length or
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-position (when indirection was used before) of preceding fields. You can
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-specify an offset relative to the end of the last up-level field using
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-.Sq &
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+position (when indirection was used before) of preceding fields.
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+You can specify an offset relative to the end of the last up-level
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+field using
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+.Sq \*[Am]
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as a prefix to the offset:
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-.Bd -literal -offset indent
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+.Bd -literal -offset indent
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0 string MZ
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->0x18 leshort >0x3f
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->>(0x3c.l) string PE\e0\e0 PE executable (MS-Windows)
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+\*[Gt]0x18 leshort \*[Gt]0x3f
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+\*[Gt]\*[Gt](0x3c.l) string PE\e0\e0 PE executable (MS-Windows)
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# immediately following the PE signature is the CPU type
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->>>&0 leshort 0x14c for Intel 80386
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->>>&0 leshort 0x184 for DEC Alpha
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+\*[Gt]\*[Gt]\*[Gt]\*[Am]0 leshort 0x14c for Intel 80386
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+\*[Gt]\*[Gt]\*[Gt]\*[Am]0 leshort 0x184 for DEC Alpha
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.Ed
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.Pp
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Indirect and relative offsets can be combined:
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-.Bd -literal -offset indent
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+.Bd -literal -offset indent
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0 string MZ
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->0x18 leshort <0x40
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->>(4.s*512) leshort !0x014c MZ executable (MS-DOS)
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+\*[Gt]0x18 leshort \*[Lt]0x40
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+\*[Gt]\*[Gt](4.s*512) leshort !0x014c MZ executable (MS-DOS)
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# if it's not COFF, go back 512 bytes and add the offset taken
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# from byte 2/3, which is yet another way of finding the start
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# of the extended executable
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->>>&(2.s-514) string LE LE executable (MS Windows VxD driver)
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+\*[Gt]\*[Gt]\*[Gt]\*[Am](2.s-514) string LE LE executable (MS Windows VxD driver)
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.Ed
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.Pp
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Or the other way around:
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-.Bd -literal -offset indent
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+.Bd -literal -offset indent
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0 string MZ
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->0x18 leshort >0x3f
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->>(0x3c.l) string LE\e0\e0 LE executable (MS-Windows)
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+\*[Gt]0x18 leshort \*[Gt]0x3f
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+\*[Gt]\*[Gt](0x3c.l) string LE\e0\e0 LE executable (MS-Windows)
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# at offset 0x80 (-4, since relative offsets start at the end
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# of the up-level match) inside the LE header, we find the absolute
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# offset to the code area, where we look for a specific signature
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->>>(&0x7c.l+0x26) string UPX \eb, UPX compressed
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+\*[Gt]\*[Gt]\*[Gt](\*[Am]0x7c.l+0x26) string UPX \eb, UPX compressed
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.Ed
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.Pp
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Or even both!
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-.Bd -literal -offset indent
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+.Bd -literal -offset indent
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0 string MZ
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->0x18 leshort >0x3f
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->>(0x3c.l) string LE\e0\e0 LE executable (MS-Windows)
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+\*[Gt]0x18 leshort \*[Gt]0x3f
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+\*[Gt]\*[Gt](0x3c.l) string LE\e0\e0 LE executable (MS-Windows)
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# at offset 0x58 inside the LE header, we find the relative offset
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# to a data area where we look for a specific signature
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->>>&(&0x54.l-3) string UNACE \eb, ACE self-extracting archive
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+\*[Gt]\*[Gt]\*[Gt]\*[Am](\*[Am]0x54.l-3) string UNACE \eb, ACE self-extracting archive
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.Ed
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.Pp
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Finally, if you have to deal with offset/length pairs in your file, even the
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second value in a parenthesized expression can be taken from the file itself,
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-using another set of parentheses. Note that this additional indirect offset
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-is always relative to the start of the main indirect offset.
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-.Bd -literal -offset indent
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+using another set of parentheses.
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+Note that this additional indirect offset is always relative to the
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+start of the main indirect offset.
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+.Bd -literal -offset indent
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0 string MZ
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->0x18 leshort >0x3f
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->>(0x3c.l) string PE\e0\e0 PE executable (MS-Windows)
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+\*[Gt]0x18 leshort \*[Gt]0x3f
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+\*[Gt]\*[Gt](0x3c.l) string PE\e0\e0 PE executable (MS-Windows)
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# search for the PE section called ".idata"...
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->>>&0xf4 search/0x140 .idata
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+\*[Gt]\*[Gt]\*[Gt]\*[Am]0xf4 search/0x140 .idata
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# ...and go to the end of it, calculated from start+length;
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# these are located 14 and 10 bytes after the section name
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->>>>(&0xe.l+(-4)) string PK\e3\e4 \eb, ZIP self-extracting archive
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+\*[Gt]\*[Gt]\*[Gt]\*[Gt](\*[Am]0xe.l+(-4)) string PK\e3\e4 \eb, ZIP self-extracting archive
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.Ed
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+.Sh SEE ALSO
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+.Xr file __CSECTION__
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+\- the command that reads this file.
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.Sh BUGS
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The formats
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.Dv long ,
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@@ -430,9 +437,6 @@ are system-dependent; perhaps they should be specified as a number
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of bytes (2B, 4B, etc),
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since the files being recognized typically come from
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a system on which the lengths are invariant.
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-.Sh SEE ALSO
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-.Xr file __CSECTION__
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-\- the command that reads this file.
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.\"
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.\" From: guy@sun.uucp (Guy Harris)
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.\" Newsgroups: net.bugs.usg
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@@ -446,4 +450,4 @@ a system on which the lengths are invariant.
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.\" the changes I posted to the S5R2 version.
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.\"
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.\" Modified for Ian Darwin's version of the file command.
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-.\" @(#)$Id: magic.man,v 1.37 2007/01/12 17:38:27 christos Exp $
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+.\" @(#)$Id: magic.man,v 1.38 2007/01/27 00:52:08 ljt Exp $
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Daniel Baumann