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.\" ========================================================================
.\"
.IX Title "Lintian::Util 3"
.TH Lintian::Util 3 "2019-05-26" "Lintian v2.15.0~bpo9+1" "Debian Package Checker"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
Lintian::Util \- Lintian utility functions
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& use Lintian::Util qw(normalize_pkg_path);
\&
\& my $path = normalize_pkg_path(\*(Aqusr/bin/\*(Aq, \*(Aq../lib/git\-core/git\-pull\*(Aq);
\& if (defined $path) {
\&    # ...
\& }
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This module contains a number of utility subs that are nice to have,
but on their own did not warrant their own module.
.PP
Most subs are imported only on request.
.SH "VARIABLES"
.IX Header "VARIABLES"
.ie n .IP "$PKGNAME_REGEX" 4
.el .IP "\f(CW$PKGNAME_REGEX\fR" 4
.IX Item "$PKGNAME_REGEX"
Regular expression that matches valid package names.  The expression
is not anchored and does not enforce any \*(L"boundary\*(R" characters.
.ie n .IP "$PKGREPACK_REGEX" 4
.el .IP "\f(CW$PKGREPACK_REGEX\fR" 4
.IX Item "$PKGREPACK_REGEX"
Regular expression that matches \*(L"repacked\*(R" package names.  The expression is
not anchored and does not enforce any \*(L"boundary\*(R" characters.
.ie n .IP "$PKGVERSION_REGEX" 4
.el .IP "\f(CW$PKGVERSION_REGEX\fR" 4
.IX Item "$PKGVERSION_REGEX"
Regular expression that matches valid package versions.  The
expression is not anchored and does not enforce any \*(L"boundary\*(R"
characters.
.SH "FUNCTIONS"
.IX Header "FUNCTIONS"
.IP "get_deb_info(\s-1DEBFILE\s0)" 4
.IX Item "get_deb_info(DEBFILE)"
Extracts the control file from \s-1DEBFILE\s0 and returns it as a hashref.
.Sp
Basically, this is a fancy convenience for setting up an ar + tar pipe
and passing said pipe to \*(L"parse_dpkg_control(HANDLE[, FLAGS[, \s-1LINES\s0]])\*(R".
.Sp
\&\s-1DEBFILE\s0 must be an ar file containing a \*(L"control.tar.gz\*(R" member, which
in turn should contain a \*(L"control\*(R" file.  If the \*(L"control\*(R" file is
empty this will return an empty list.
.Sp
Note: the control file is only expected to have a single paragraph and
thus only the first is returned (in the unlikely case that there are
more than one).
.Sp
This function may fail with any of the messages that
\&\*(L"parse_dpkg_control\*(R" do.  It can also emit:
.Sp
.Vb 1
\& "cannot fork to unpack %s: %s\en"
.Ve
.IP "get_dsc_control (\s-1DSCFILE\s0)" 4
.IX Item "get_dsc_control (DSCFILE)"
Convenience function for reading dsc files.  It will read the \s-1DSCFILE\s0
using \*(L"read_dpkg_control(FILE[, FLAGS[, \s-1LINES\s0]])\*(R" and then return the
first paragraph.  If the file has no paragraphs, \f(CW\*(C`undef\*(C'\fR is returned
instead.
.Sp
Note: the control file is only expected to have a single paragraph and
thus only the first is returned (in the unlikely case that there are
more than one).
.Sp
This function may fail with any of the messages that
\&\*(L"read_dpkg_control(FILE[, FLAGS[, \s-1LINES\s0]])\*(R" do.
.IP "drain_pipe(\s-1FD\s0)" 4
.IX Item "drain_pipe(FD)"
Reads and discards any remaining contents from \s-1FD,\s0 which is assumed to
be a pipe.  This is mostly done to avoid having the \*(L"write\*(R"\-end die
with a \s-1SIGPIPE\s0 due to a \*(L"broken pipe\*(R" (which can happen if you just
close the pipe).
.Sp
May cause an exception if there are issues reading from the pipe.
.Sp
Caveat: This will block until the pipe is closed from the \*(L"write\*(R"\-end,
so only use it with pipes where the \*(L"write\*(R"\-end will eventually close
their end by themselves (or something else will make them close it).
.IP "get_file_digest(\s-1ALGO, FILE\s0)" 4
.IX Item "get_file_digest(ALGO, FILE)"
Creates an \s-1ALGO\s0 digest object that is seeded with the contents of
\&\s-1FILE. \s0 If you just want the hex digest, please use
\&\*(L"get_file_checksum(\s-1ALGO, FILE\s0)\*(R" instead.
.Sp
\&\s-1ALGO\s0 can be 'md5' or shaX, where X is any number supported by
Digest::SHA (e.g. 'sha256').
.Sp
This sub is a convenience wrapper around Digest::{\s-1MD5,SHA\s0}.
.IP "get_file_checksum(\s-1ALGO, FILE\s0)" 4
.IX Item "get_file_checksum(ALGO, FILE)"
Returns a hexadecimal string of the message digest checksum generated
by the algorithm \s-1ALGO\s0 on \s-1FILE.\s0
.Sp
\&\s-1ALGO\s0 can be 'md5' or shaX, where X is any number supported by
Digest::SHA (e.g. 'sha256').
.Sp
This sub is a convenience wrapper around Digest::{\s-1MD5,SHA\s0}.
.IP "is_string_utf8_encoded(\s-1STRING\s0)" 4
.IX Item "is_string_utf8_encoded(STRING)"
Returns a truth value if \s-1STRING\s0 can be decoded as valid \s-1UTF\-8.\s0
.IP "file_is_encoded_in_non_utf8 (...)" 4
.IX Item "file_is_encoded_in_non_utf8 (...)"
Undocumented
.IP "\fIdo_fork()\fR" 4
.IX Item "do_fork()"
Overrides fork to reset signal handlers etc. in the child.
.IP "clean_env ([\s-1CLOC\s0])" 4
.IX Item "clean_env ([CLOC])"
Destructively cleans \f(CW%ENV\fR \- removes all variables \f(CW%ENV\fR except a
selected few whitelisted variables.
.Sp
The list of whitelisted \f(CW%ENV\fR variables are:
.Sp
.Vb 3
\& PATH
\& LC_ALL (*)
\& TMPDIR
.Ve
.Sp
(*) \s-1LC_ALL\s0 is a special case as clean_env will change its value to
either \*(L"C.UTF\-8\*(R" or \*(L"C\*(R" (if \s-1CLOC\s0 is given and a truth value).
.IP "perm2oct(\s-1PERM\s0)" 4
.IX Item "perm2oct(PERM)"
Translates \s-1PERM\s0 to an octal permission.  \s-1PERM\s0 should be a string describing
the permissions as done by \fItar t\fR or \fIls \-l\fR.  That is, it should be a
string like \*(L"\-rw\-r\*(--r\-\-\*(R".
.Sp
If the string does not appear to be a valid permission, it will cause
a trappable error.
.Sp
Examples:
.Sp
.Vb 3
\& # Good
\& perm2oct(\*(Aq\-rw\-r\-\-r\-\-\*(Aq) == 0644
\& perm2oct(\*(Aq\-rwxr\-xr\-x\*(Aq) == 0755
\&
\& # Bad
\& perm2oct(\*(Aqbroken\*(Aq)      # too short to be recognised
\& perm2oct(\*(Aq\-resurunet\*(Aq)  # contains unknown permissions
.Ve
.IP "run_cmd([\s-1OPTS, \s0]COMMAND[, \s-1ARGS...\s0])" 4
.IX Item "run_cmd([OPTS, ]COMMAND[, ARGS...])"
Executes the given \f(CW\*(C`COMMAND\*(C'\fR with the (optional) arguments \f(CW\*(C`ARGS\*(C'\fR and
returns the status code as one would see it from a shell script.  Shell
features cannot be used.
.Sp
\&\s-1OPTS,\s0 if given, is a hash reference with zero or more of the following key-value pairs:
.RS 4
.IP "chdir" 4
.IX Item "chdir"
The child process with chdir to the given directory before executing the command.
.IP "in" 4
.IX Item "in"
The \s-1STDIN\s0 of the child process will be reopened and read from the filename denoted by the value of this key.
By default, \s-1STDIN\s0 will reopened to read from /dev/null.
.IP "out" 4
.IX Item "out"
The \s-1STDOUT\s0 of the child process will be reopened and write to filename denoted by the value of this key.
By default, \s-1STDOUT\s0 is discarded.
.IP "update-env-vars" 4
.IX Item "update-env-vars"
Each key/value pair defined in the hashref associated with \fBupdate-env-vars\fR will be updated in the
child processes's environment.  If a value is \f(CW\*(C`undef\*(C'\fR, then the corresponding environment variable
will be removed (if set).  Otherwise, the environment value will be set to that value.
.RE
.RS 4
.RE
.IP "copy_dir (\s-1ARGS\s0)" 4
.IX Item "copy_dir (ARGS)"
Convenient way of calling \fIcp \-a \s-1ARGS\s0\fR.
.IP "gunzip_file (\s-1IN, OUT\s0)" 4
.IX Item "gunzip_file (IN, OUT)"
Decompresses contents of the file \s-1IN\s0 and stores the contents in the
file \s-1OUT.  IN\s0 is \fInot\fR removed by this call.  On error, this function
will cause a trappable error.
.IP "open_gz (\s-1FILE\s0)" 4
.IX Item "open_gz (FILE)"
Opens a handle that reads from the GZip compressed \s-1FILE.\s0
.Sp
On failure, this sub emits a trappable error.
.Sp
Note: The handle may be a pipe from an external processes.
.IP "internal_error (MSG[, ...])" 4
.IX Item "internal_error (MSG[, ...])"
Use to signal an internal error. The argument(s) will used to print a
diagnostic message to the user.
.Sp
If multiple arguments are given, they will be merged into a single
string (by join (' ', \f(CW@_\fR)).  If only one argument is given it will be
stringified and used directly.
.IP "fail (MSG[, ...])" 4
.IX Item "fail (MSG[, ...])"
Deprecated alias of \*(L"internal_error\*(R".
.IP "locate_helper_tool(\s-1TOOLNAME\s0)" 4
.IX Item "locate_helper_tool(TOOLNAME)"
Given the name of a helper tool, returns the path to it.  The tool
must be available in the \*(L"helpers\*(R" subdir of one of the \*(L"lintian root\*(R"
directories used by Lintian.
.Sp
The tool name should follow the same rules as check names.
Particularly, third-party checks should namespace their tools in the
same way they namespace their checks.  E.g. \*(L"python/some\-helper\*(R".
.Sp
If the tool cannot be found, this sub will cause a trappable error.
.IP "strip ([\s-1LINE\s0])" 4
.IX Item "strip ([LINE])"
Strips whitespace from the beginning and the end of \s-1LINE\s0 and returns
it.  If \s-1LINE\s0 is omitted, \f(CW$_\fR will be used instead. Example
.Sp
.Vb 1
\& @lines = map { strip } <$fd>;
.Ve
.Sp
In void context, the input argument will be modified so it can be
used as a replacement for chomp in some cases:
.Sp
.Vb 4
\&  while ( my $line = <$fd> ) {
\&    strip ($line);
\&    # $line no longer has any leading or trailing whitespace
\&  }
.Ve
.Sp
Otherwise, a copy of the string is returned:
.Sp
.Vb 6
\&  while ( my $orig = <$fd> ) {
\&    my $stripped = strip ($orig);
\&    if ($stripped ne $orig) {
\&        # $orig had leading or/and trailing whitespace
\&    }
\&  }
.Ve
.IP "lstrip ([\s-1LINE\s0])" 4
.IX Item "lstrip ([LINE])"
Like strip but only strip leading whitespace.
.IP "rstrip ([\s-1LINE\s0])" 4
.IX Item "rstrip ([LINE])"
Like strip but only strip trailing whitespace.
.IP "check_path (\s-1CMD\s0)" 4
.IX Item "check_path (CMD)"
Returns 1 if \s-1CMD\s0 can be found in \s-1PATH \s0(i.e. \f(CW$ENV\fR{\s-1PATH\s0}) and is
executable.  Otherwise, the function return 0.
.IP "dequote_name(\s-1STR, REMOVESLASH\s0)" 4
.IX Item "dequote_name(STR, REMOVESLASH)"
Strip an extra layer quoting in index file names and optionally
remove an initial \*(L"./\*(R" if any.
.Sp
Remove initial ./ by default
.IP "signal_number2name(\s-1NUM\s0)" 4
.IX Item "signal_number2name(NUM)"
Given a number, returns the name of the signal (without leading
\&\*(L"\s-1SIG\*(R"\s0).  Example:
.Sp
.Vb 1
\&    signal_number2name(2) eq \*(AqINT\*(Aq
.Ve
.IP "normalize_pkg_path(\s-1PATH\s0)" 4
.IX Item "normalize_pkg_path(PATH)"
Normalize \s-1PATH\s0 by removing superfluous path segments.  \s-1PATH\s0 is assumed
to be relative the package root.  Note that the result will never
start nor end with a slash, even if \s-1PATH\s0 does.
.Sp
As the name suggests, this is a path \*(L"normalization\*(R" rather than a
true path resolution (for that use Cwd::realpath).  Particularly,
it assumes none of the path segments are symlinks.
.Sp
normalize_pkg_path will return \f(CW\*(C`q{}\*(C'\fR (i.e. the empty string) if \s-1PATH\s0
is normalized to the root dir and \f(CW\*(C`undef\*(C'\fR if the path cannot be
normalized without escaping the package root.
.Sp
Examples:
  normalize_pkg_path('usr/share/java/../../../usr/share/ant/file')
    eq 'usr/share/ant/file'
  normalize_pkg_path('usr/..') eq q{};
.Sp
.Vb 2
\& The following will return C<undef>:
\&  normalize_pkg_path(\*(Aqusr/bin/../../../../etc/passwd\*(Aq)
.Ve
.IP "normalize_pkg_path(\s-1CURDIR, LINK_TARGET\s0)" 4
.IX Item "normalize_pkg_path(CURDIR, LINK_TARGET)"
Normalize the path obtained by following a link with \s-1LINK_TARGET\s0 as
its target from \s-1CURDIR\s0 as the current directory.  \s-1CURDIR\s0 is assumed to
be relative to the package root.  Note that the result will never
start nor end with a slash, even if \s-1CURDIR\s0 or \s-1DEST\s0 does.
.Sp
normalize_pkg_path will return \f(CW\*(C`q{}\*(C'\fR (i.e. the empty string) if the
target is the root dir and \f(CW\*(C`undef\*(C'\fR if the path cannot be normalized
without escaping the package root.
.Sp
\&\fB\s-1CAVEAT\s0\fR: This function is \fInot always sufficient\fR to test if it is
safe to open a given symlink.  Use
is_ancestor_of for
that.  If you must use this function, remember to check that the
target is not a symlink (or if it is, that it can be resolved safely).
.Sp
Examples:
.Sp
.Vb 6
\&  normalize_pkg_path(\*(Aqusr/share/java\*(Aq, \*(Aq../ant/file\*(Aq) eq \*(Aqusr/share/ant/file\*(Aq
\&  normalize_pkg_path(\*(Aqusr/share/java\*(Aq, \*(Aq../../../usr/share/ant/file\*(Aq)
\&  normalize_pkg_path(\*(Aqusr/share/java\*(Aq, \*(Aq/usr/share/ant/file\*(Aq)
\&    eq \*(Aqusr/share/ant/file\*(Aq
\&  normalize_pkg_path(\*(Aq/usr/share/java\*(Aq, \*(Aq/\*(Aq) eq q{};
\&  normalize_pkg_path(\*(Aq/\*(Aq, \*(Aqusr/..\*(Aq) eq q{};
\&
\& The following will return C<undef>:
\&  normalize_pkg_path(\*(Aqusr/bin\*(Aq, \*(Aq../../../../etc/passwd\*(Aq)
\&  normalize_pkg_path(\*(Aqusr/bin\*(Aq, \*(Aq/../etc/passwd\*(Aq)
.Ve
.IP "parse_boolean (\s-1STR\s0)" 4
.IX Item "parse_boolean (STR)"
Attempt to parse \s-1STR\s0 as a boolean and return its value.
If \s-1STR\s0 is not a valid/recognised boolean, the sub will
invoke croak.
.Sp
The following values recognised (string checks are not
case sensitive):
.RS 4
.IP "The integer 0 is considered false" 4
.IX Item "The integer 0 is considered false"
.PD 0
.IP "Any non-zero integer is considered true" 4
.IX Item "Any non-zero integer is considered true"
.ie n .IP """true"", ""y"" and ""yes"" are considered true" 4
.el .IP "``true'', ``y'' and ``yes'' are considered true" 4
.IX Item "true, y and yes are considered true"
.ie n .IP """false"", ""n"" and ""no"" are considered false" 4
.el .IP "``false'', ``n'' and ``no'' are considered false" 4
.IX Item "false, n and no are considered false"
.RE
.RS 4
.RE
.IP "is_ancestor_of(\s-1PARENTDIR, PATH\s0)" 4
.IX Item "is_ancestor_of(PARENTDIR, PATH)"
.PD
Returns true if and only if \s-1PATH\s0 is \s-1PARENTDIR\s0 or a path stored
somewhere within \s-1PARENTDIR \s0(or its subdirs).
.Sp
This function will resolve the paths; any failure to resolve the path
will cause a trappable error.
.IP "pipe_tee(\s-1INHANDLE,\s0 OUTHANDLES[, \s-1OPTS\s0])" 4
.IX Item "pipe_tee(INHANDLE, OUTHANDLES[, OPTS])"
Read bytes from \s-1INHANDLE\s0 and copy them into all of the handles in the
listref \s-1OUTHANDLES.\s0 The optional \s-1OPTS\s0 argument is a hashref of
options, see below.
.Sp
The subroutine will continue to read from \s-1INHANDLE\s0 until it is
exhausted or an error occurs (either during read or write).  In case
of errors, a trappable error will be raised.  The handles are left
open when the subroutine returns, caller must close them afterwards.
.Sp
Caller should ensure that handles are using \*(L"blocking\*(R" I/O.  The
subroutine will use sysread and
syswrite when reading and writing.
.Sp
\&\s-1OPTS,\s0 if given, may contain the following key-value pairs:
.RS 4
.IP "chunk_size" 4
.IX Item "chunk_size"
A suggested buffer size for read/write.  If given, it will be to
sysread as \s-1LENGTH\s0 argument when reading from \s-1INHANDLE.\s0
.RE
.RS 4
.RE
.IP "untaint(\s-1VALUE\s0)" 4
.IX Item "untaint(VALUE)"
Untaint \s-1VALUE\s0
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fIlintian\fR\|(1)