GLOB(3) OpenBSD Programmer's Manual GLOB(3)NAME
glob, globfree - generate pathnames matching a pattern
SYNOPSIS
#include <glob.h>
int
glob(const char *pattern, int flags, const int (*errfunc)(const char *,
int), glob_t *pglob);
void
globfree(glob_t *pglob);
DESCRIPTION
The glob() function is a pathname generator that implements the rules for
file name pattern matching used by the shell.
The include file <glob.h> defines the structure type glob_t, which
contains at least the following fields:
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;
The argument pattern is a pointer to a pathname pattern to be expanded.
glob() matches all accessible pathnames against the pattern and creates a
list of the pathnames that match. In order to have access to a pathname,
glob() requires search permission on every component of a path except the
last and read permission on each directory of any filename component of
pattern that contains any of the special characters `*', `?', or `['.
The number of matched pathnames is stored in the gl_pathc field, and a
pointer to a list of pointers to pathnames in the gl_pathv field. The
first pointer after the last pathname is NULL. If the pattern does not
match any pathnames, the returned number of matched paths is set to zero.
It is the caller's responsibility to create the structure pointed to by
pglob. The glob() function allocates other space as needed, including
the memory pointed to by gl_pathv.
The argument flags is used to modify the behavior of glob(). The value
of flags is the bitwise inclusive OR of any of the following values
defined in <glob.h>:
GLOB_APPEND Append pathnames generated to the ones from a previous
call (or calls) to glob(). The value of 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
GLOB_DOOFFS flag, nor change the value of gl_offs when
GLOB_DOOFFS is set, nor (obviously) call globfree() for
pglob.
GLOB_DOOFFS Make use of the gl_offs field. If this flag is set,
gl_offs is used to specify how many null pointers to
prepend to the beginning of the gl_pathv field. In
other words, gl_pathv will point to gl_offs null
pointers, followed by gl_pathc pathname pointers,
followed by a null pointer.
GLOB_ERR Causes glob() to return when it encounters a directory
that it cannot open or read. Ordinarily, glob()
continues to find matches.
GLOB_MARK Each pathname that is a directory that matches pattern
has a slash appended.
GLOB_NOCHECK If pattern does not match any pathname, then glob()
returns a list consisting of only pattern, with the
number of total pathnames set to 1, and the number of
matched pathnames set to 0.
GLOB_NOESCAPE Normally, every occurrence of a backslash (`\') followed
by a character in pattern is replaced by that character.
This is done to negate any special meaning for the
character. If the GLOB_NOESCAPE flag is set, a
backslash character is treated as an ordinary character.
GLOB_NOSORT By default, the pathnames are sorted in ascending ASCII
order; this flag prevents that sorting (speeding up
glob()).
The following values may also be included in flags, however, they are
non-standard extensions to IEEE Std 1003.2 (``POSIX.2'').
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:
void *(*gl_opendir)(const char *);
struct dirent *(*gl_readdir)(void *);
void (*gl_closedir)(void *);
int (*gl_lstat)(const char *, struct stat *);
int (*gl_stat)(const char *, struct stat *);
This extension is provided to allow programs such as
restore(8) to provide globbing from directories stored
on tape.
GLOB_BRACE Pre-process the pattern string to expand `{pat,pat,...}'
strings like csh(1). The pattern `{}' is left
unexpanded for historical reasons. (csh(1) does the
same thing to ease typing of find(1) patterns.)
GLOB_KEEPSTAT Retain a copy of the stat(2) information retrieved for
matching paths in the gl_statv array:
struct stat **gl_statv;
This option may be used to avoid lstat(2) lookups in
cases where they are expensive.
GLOB_MAGCHAR Set by the glob() function if the pattern included
globbing characters. See the description of the usage
of the gl_matchc structure member for more details.
GLOB_NOMAGIC Is the same as GLOB_NOCHECK but it only appends the
pattern if it does not contain any of the special
characters `*', `?', or `['. GLOB_NOMAGIC is provided
to simplify implementing the historic csh(1) globbing
behavior and should probably not be used anywhere else.
GLOB_QUOTE This option has no effect and is included for backwards
compatibility with older sources.
GLOB_TILDE Expand patterns that start with `~' to user name home
directories.
GLOB_LIMIT Limit the amount of memory used to store matched strings
to 64K, the number of stat(2) calls to 128, and the
number of readdir(3) calls to 16K. This option should
be set for programs that can be coerced to a denial of
service attack via patterns that expand to a very large
number of matches, such as a long string of `*/../*/..'.
If, during the search, a directory is encountered that cannot be opened
or read and errfunc is non-null, glob() calls (*errfunc)(path, errno).
This may be unintuitive: a pattern like ``*/Makefile'' will try to
stat(2) ``foo/Makefile'' even if ``foo'' is not a directory, resulting in
a call to errfunc. The error routine can suppress this action by testing
for ENOENT and ENOTDIR; however, the GLOB_ERR flag will still cause an
immediate return when this happens.
If errfunc returns non-zero, glob() stops the scan and returns
GLOB_ABORTED after setting gl_pathc and gl_pathv to reflect any paths
already matched. This also happens if an error is encountered and
GLOB_ERR is set in flags, regardless of the return value of errfunc, if
called. If GLOB_ERR is not set and either errfunc is NULL or errfunc
returns zero, the error is ignored.
The globfree() function frees any space associated with pglob from a
previous call(s) to glob().
RETURN VALUES
On successful completion, glob() returns zero. In addition the fields of
pglob contain the values described below:
gl_pathc Contains the total number of matched pathnames so far.
This includes other matches from previous invocations of
glob() if GLOB_APPEND was specified.
gl_matchc Contains the number of matched pathnames in the current
invocation of glob().
gl_flags Contains a copy of the flags parameter with the bit
GLOB_MAGCHAR set if pattern contained any of the special
characters `*', `?', or `[', cleared if not.
gl_pathv Contains a pointer to a null-terminated list of matched
pathnames. However, if gl_pathc is zero, the contents of
gl_pathv are undefined.
gl_statv If the GLOB_KEEPSTAT flag was set, gl_statv contains a
pointer to a null-terminated list of matched stat(2)
objects corresponding to the paths in gl_pathc.
If 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
<glob.h>:
GLOB_NOSPACE An attempt to allocate memory failed, or if errno was 0
GLOB_LIMIT was specified in the flags and ARG_MAX or more
patterns were matched.
GLOB_ABORTED The scan was stopped because an error was encountered and
either GLOB_ERR was set, or (*errfunc)() returned non-zero.
GLOB_NOMATCH The pattern did not match a pathname and GLOB_NOCHECK was
not set.
GLOB_NOSYS The requested function is not supported by this version of
glob().
The arguments pglob->gl_pathc and pglob->gl_pathv are still set as
specified above.
EXAMPLES
A rough equivalent of `ls -l *.c *.h' can be obtained with the following
code:
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);
ERRORS
The glob() function may fail and set errno for any of the errors
specified for the library routines stat(2), closedir(3), opendir(3),
readdir(3), malloc(3), and free(3).
SEE ALSOsh(1), fnmatch(3), regex(3), glob(7)STANDARDS
The glob() function is expected to conform to IEEE Std 1003.2
(``POSIX.2'') and X/Open Portability Guide Issue 4.2 (``XPG4.2''). Note,
however, that the flags GLOB_ALTDIRFUNC, GLOB_BRACE, GLOB_KEEPSTAT,
GLOB_MAGCHAR, GLOB_NOMAGIC, GLOB_QUOTE, GLOB_TILDE, and GLOB_LIMIT and
the fields gl_matchc, gl_statv and gl_flags should not be used by
applications striving for strict standards conformance.
HISTORY
The glob() and globfree() functions first appeared in 4.4BSD.
BUGS
Patterns longer than MAXPATHLEN may cause unchecked errors.
OpenBSD 4.9 October 8, 2010 OpenBSD 4.9
