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.\"     @(#)glob.3      8.3 (Berkeley) 4/16/94

.\" $FreeBSD: src/lib/libc/gen/glob.3,v 1.20 2001/10/01 16:08:51 ru Exp $

.\"

.Dd April 16, 1994

.Dt GLOB 3

.Os

.Sh NAME

.Nm glob ,

.Nm globfree

.Nd generate pathnames matching a pattern

.Sh LIBRARY

.Lb libc

.Sh SYNOPSIS

.In glob.h

.Ft int

.Fn glob "const char *pattern" "int flags" "int (*errfunc)(const char *, int)" "glob_t *pglob"

.Ft void

.Fn globfree "glob_t *pglob"

.Sh DESCRIPTION

The

.Fn glob

function

is a pathname generator that implements the rules for file name pattern

matching used by the shell.

.Pp

The include file

.Pa glob.h

defines the structure type

.Fa glob_t ,

which contains at least the following fields:

.Bd -literal

typedef struct {

        int gl_pathc;           /* count of total paths so far */

        int gl_matchc;          /* count of paths matching pattern */

        int gl_offs;            /* reserved at beginning of gl_pathv */

        int gl_flags;           /* returned flags */

        char **gl_pathv;        /* list of paths matching pattern */

} glob_t;

.Ed

.Pp

The argument

.Fa pattern

is a pointer to a pathname pattern to be expanded.

The

.Fn glob

argument

matches all accessible pathnames against the pattern and creates

a list of the pathnames that match.

In order to have access to a pathname,

.Fn glob

requires search permission on every component of a path except the last

and read permission on each directory of any filename component of

.Fa pattern

that contains any of the special characters

.Ql * ,

.Ql ?\&

or

.Ql \&[ .

.Pp

The

.Fn glob

argument

stores the number of matched pathnames into the

.Fa gl_pathc

field, and a pointer to a list of pointers to pathnames into the

.Fa gl_pathv

field.

The first pointer after the last pathname is

.Dv NULL .

If the pattern does not match any pathnames, the returned number of

matched paths is set to zero.

.Pp

It is the caller's responsibility to create the structure pointed to by

.Fa pglob .

The

.Fn glob

function allocates other space as needed, including the memory pointed

to by

.Fa gl_pathv .

.Pp

The argument

.Fa flags

is used to modify the behavior of

.Fn glob .

The value of

.Fa flags

is the bitwise inclusive

.Tn OR

of any of the following

values defined in

.Pa glob.h :

.Bl -tag -width GLOB_ALTDIRFUNC

.It Dv GLOB_APPEND

Append pathnames generated to the ones from a previous call (or calls)

to

.Fn glob .

The value of

.Fa gl_pathc

will be the total matches found by this call and the previous call(s).

The pathnames are appended to, not merged with the pathnames returned by

the previous call(s).

Between calls, the caller must not change the setting of the

.Dv GLOB_DOOFFS

flag, nor change the value of

.Fa gl_offs

when

.Dv GLOB_DOOFFS

is set, nor (obviously) call

.Fn globfree

for

.Fa pglob .

.It Dv GLOB_DOOFFS

Make use of the

.Fa gl_offs

field.

If this flag is set,

.Fa gl_offs

is used to specify how many

.Dv NULL

pointers to prepend to the beginning

of the

.Fa gl_pathv

field.

In other words,

.Fa gl_pathv

will point to

.Fa gl_offs

.Dv NULL

pointers,

followed by

.Fa gl_pathc

pathname pointers, followed by a

.Dv NULL

pointer.

.It Dv GLOB_ERR

Causes

.Fn glob

to return when it encounters a directory that it cannot open or read.

Ordinarily,

.Fn glob

continues to find matches.

.It Dv GLOB_MARK

Each pathname that is a directory that matches

.Fa pattern

has a slash

appended.

.It Dv GLOB_NOCHECK

If

.Fa pattern

does not match any pathname, then

.Fn glob

returns a list

consisting of only

.Fa pattern ,

with the number of total pathnames is set to 1, and the number of matched

pathnames set to 0.

If

.Dv GLOB_QUOTE

is set, its effect is present in the pattern returned.

.It Dv GLOB_NOSORT

By default, the pathnames are sorted in ascending

.Tn ASCII

order;

this flag prevents that sorting (speeding up

.Fn glob ) .

.El

.Pp

The following values may also be included in

.Fa flags ,

however, they are non-standard extensions to

.St -p1003.2 .

.Bl -tag -width GLOB_ALTDIRFUNC

.It Dv GLOB_ALTDIRFUNC

The following additional fields in the pglob structure have been

initialized with alternate functions for glob to use to open, read,

and close directories and to get stat information on names found

in those directories.

.Bd -literal

void *(*gl_opendir)(const char * name);

struct dirent *(*gl_readdir)(void *);

void (*gl_closedir)(void *);

int (*gl_lstat)(const char *name, struct stat *st);

int (*gl_stat)(const char *name, struct stat *st);

.Ed

.Pp

This extension is provided to allow programs such as

.Xr restore 8

to provide globbing from directories stored on tape.

.It Dv GLOB_BRACE

Pre-process the pattern string to expand

.Ql {pat,pat,...}

strings like

.Xr csh 1 .

The pattern

.Ql {}

is left unexpanded for historical reasons (and

.Xr csh 1

does the same thing to

ease typing

of

.Xr find 1

patterns).

.It Dv GLOB_MAGCHAR

Set by the

.Fn glob

function if the pattern included globbing characters.

See the description of the usage of the

.Fa gl_matchc

structure member for more details.

.It Dv GLOB_NOMAGIC

Is the same as

.Dv GLOB_NOCHECK

but it only appends the

.Fa pattern

if it does not contain any of the special characters ``*'', ``?'' or ``[''.

.Dv GLOB_NOMAGIC

is provided to simplify implementing the historic

.Xr csh 1

globbing behavior and should probably not be used anywhere else.

.It Dv GLOB_QUOTE

Use the backslash

.Pq Ql \e

character for quoting: every occurrence of

a backslash followed by a character in the pattern is replaced by that

character, avoiding any special interpretation of the character.

.It Dv GLOB_TILDE

Expand patterns that start with

.Ql ~

to user name home directories.

.It Dv GLOB_LIMIT

Limit the total number of returned pathnames to the value provided in

.Fa gl_matchc

(default

.Dv ARG_MAX ) .

This option should be set for programs

that can be coerced into a denial of service attack

via patterns that expand to a very large number of matches,

such as a long string of

.Ql */../*/.. .

.El

.Pp

If, during the search, a directory is encountered that cannot be opened

or read and

.Fa errfunc

is

.Pf non- Dv NULL ,

.Fn glob

calls

.Fa \*(lp*errfunc\*(rp Ns ( Fa path , errno ) .

This may be unintuitive: a pattern like

.Ql */Makefile

will try to

.Xr stat 2

.Ql foo/Makefile

even if

.Ql foo

is not a directory, resulting in a

call to

.Fa errfunc .

The error routine can suppress this action by testing for

.Er ENOENT

and

.Er ENOTDIR ;

however, the

.Dv GLOB_ERR

flag will still cause an immediate

return when this happens.

.Pp

If

.Fa errfunc

returns non-zero,

.Fn glob

stops the scan and returns

.Dv GLOB_ABEND

after setting

.Fa gl_pathc

and

.Fa gl_pathv

to reflect any paths already matched.

This also happens if an error is encountered and

.Dv GLOB_ERR

is set in

.Fa flags ,

regardless of the return value of

.Fa errfunc ,

if called.

If

.Dv GLOB_ERR

is not set and either

.Fa errfunc

is

.Dv NULL

or

.Fa errfunc

returns zero, the error is ignored.

.Pp

The

.Fn globfree

function frees any space associated with

.Fa pglob

from a previous call(s) to

.Fn glob .

.Sh RETURN VALUES

On successful completion,

.Fn glob

returns zero.

In addition the fields of

.Fa pglob

contain the values described below:

.Bl -tag -width GLOB_NOCHECK

.It Fa gl_pathc

contains the total number of matched pathnames so far.

This includes other matches from previous invocations of

.Fn glob

if

.Dv GLOB_APPEND

was specified.

.It Fa gl_matchc

contains the number of matched pathnames in the current invocation of

.Fn glob .

.It Fa gl_flags

contains a copy of the

.Fa flags

parameter with the bit

.Dv GLOB_MAGCHAR

set if

.Fa pattern

contained any of the special characters ``*'', ``?'' or ``['', cleared

if not.

.It Fa gl_pathv

contains a pointer to a

.Dv NULL Ns -terminated

list of matched pathnames.

However, if

.Fa gl_pathc

is zero, the contents of

.Fa gl_pathv

are undefined.

.El

.Pp

If

.Fn glob

terminates due to an error, it sets errno and returns one of the

following non-zero constants, which are defined in the include

file

.Aq Pa glob.h :

.Bl -tag -width GLOB_NOCHECK

.It Dv GLOB_NOSPACE

An attempt to allocate memory failed, or if

.Fa errno

was 0

.Dv GLOB_LIMIT

was specified in the flags and

.Fa pglob\->gl_matchc

or more patterns were matched.

.It Dv GLOB_ABEND

The scan was stopped because an error was encountered and either

.Dv GLOB_ERR

was set or

.Fa \*(lp*errfunc\*(rp\*(lp\*(rp

returned non-zero.

.El

.Pp

The arguments

.Fa pglob\->gl_pathc

and

.Fa pglob\->gl_pathv

are still set as specified above.

.Sh EXAMPLES

A rough equivalent of

.Ql "ls -l *.c *.h"

can be obtained with the

following code:

.Bd -literal -offset indent

glob_t g;

g.gl_offs = 2;

glob("*.c", GLOB_DOOFFS, NULL, &g);

glob("*.h", GLOB_DOOFFS | GLOB_APPEND, NULL, &g);

g.gl_pathv[0] = "ls";

g.gl_pathv[1] = "-l";

execvp("ls", g.gl_pathv);

.Ed

.Sh SEE ALSO

.Xr sh 1 ,

.Xr fnmatch 3 ,

.Xr regexp 3

.Sh STANDARDS

The

.Fn glob

function is expected to be

.St -p1003.2

compatible with the exception

that the flags

.Dv GLOB_ALTDIRFUNC ,

.Dv GLOB_BRACE ,

.Dv GLOB_LIMIT ,

.Dv GLOB_MAGCHAR ,

.Dv GLOB_NOMAGIC ,

.Dv GLOB_QUOTE ,

and

.Dv GLOB_TILDE ,

and the fields

.Fa gl_matchc

and

.Fa gl_flags

should not be used by applications striving for strict

.Tn POSIX

conformance.

.Sh HISTORY

The

.Fn glob

and

.Fn globfree

functions first appeared in

.Bx 4.4 .

.Sh BUGS

Patterns longer than

.Dv MAXPATHLEN

may cause unchecked errors.

.Pp

The

.Fn glob

argument

may fail and set errno for any of the errors specified for the

library routines

.Xr stat 2 ,

.Xr closedir 3 ,

.Xr opendir 3 ,

.Xr readdir 3 ,

.Xr malloc 3 ,

and

.Xr free 3 .