glob, globfree - generate pathnames matching a pattern
#include <glob.h>
int
glob(const char *pattern, int flags,
const int (*errfunc)(const char *, int), glob_t
*pglob);
void
globfree(glob_t *pglob);
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 *
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);
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_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 by matches
to ARG_MAX.
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().
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.
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.
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);
sh(1), fnmatch(3), regexp(3)
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_MAGCHAR,
GLOB_NOMAGIC, GLOB_QUOTE, GLOB_TILDE, and GLOB_LIMIT and the
fields
gl_matchc and gl_flags should not be used by applications
striving for
strict standards conformance.
The glob() and globfree() functions first appeared in
4.4BSD.
Patterns longer than MAXPATHLEN may cause unchecked 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).
OpenBSD 3.6 April 16, 1994
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