Commit f41fdcf1 authored by Guillem Jover's avatar Guillem Jover

Add funopen() function

This is a wrapper over the glibc fopencookie() function.

We diverge from the FreeBSD, OpenBSD and DragonFlyBSD declarations,
because seekfn() there wrongly uses fpos_t, assuming it's an integral
type, and any code using that on a system where fpos_t is a struct
(such as GNU-based systems or NetBSD) will fail to build. In which case,
as the code has to be modified anyway, we might just as well use the
correct declaration.
parent 86cbff38
......@@ -124,7 +124,7 @@ AC_LINK_IFELSE(
AC_MSG_RESULT([yes])],
[AC_MSG_RESULT([no])])
AC_CHECK_FUNCS([clearenv dirfd __fpurge getexecname getline sysconf])
AC_CHECK_FUNCS([clearenv dirfd fopencookie __fpurge getexecname getline sysconf])
AC_CONFIG_FILES([
Makefile
......
......@@ -46,6 +46,23 @@ const char *fmtcheck(const char *, const char *);
char *fgetln(FILE *fp, size_t *lenp);
/*
* Note: We diverge from the FreeBSD, OpenBSD and DragonFlyBSD declarations,
* because seekfn() there wrongly uses fpos_t, assuming it's an integral
* type, and any code using that on a system where fpos_t is a struct
* (such as GNU-based systems or NetBSD) will fail to build. In which case,
* as the code has to be modified anyway, we might just as well use the
* correct declaration here.
*/
FILE *funopen(const void *cookie,
int (*readfn)(void *cookie, char *buf, int size),
int (*writefn)(void *cookie, const char *buf, int size),
off_t (*seekfn)(void *cookie, off_t offset, int whence),
int (*closefn)(void *cookie));
#define fropen(cookie, fn) funopen(cookie, fn, NULL, NULL, NULL)
#define fwopen(cookie, fn) funopen(cookie, NULL, fn, NULL, NULL)
int fpurge(FILE *fp);
__END_DECLS
......
......@@ -28,6 +28,7 @@ dist_man_MANS = \
flopen.3 \
fmtcheck.3 \
fparseln.3 \
funopen.3 \
getmode.3 \
getpeereid.3 \
getprogname.3 \
......
.\" Copyright (c) 1990, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek.
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)funopen.3 8.1 (Berkeley) 6/9/93
.\" $FreeBSD$
.\"
.Dd March 19, 2004
.Dt FUNOPEN 3
.Os
.Sh NAME
.Nm funopen ,
.Nm fropen ,
.Nm fwopen
.Nd open a stream
.Sh LIBRARY
.ds str-Lb-libbsd Utility functions from BSD systems (libbsd, \-lbsd)
.Lb libbsd
.Sh SYNOPSIS
.In bsd/stdio.h
.Ft FILE *
.Fn funopen "const void *cookie" "int (*readfn)(void *, char *, int)" "int (*writefn)(void *, const char *, int)" "off_t (*seekfn)(void *, off_t, int)" "int (*closefn)(void *)"
.Ft FILE *
.Fn fropen "void *cookie" "int (*readfn)(void *, char *, int)"
.Ft FILE *
.Fn fwopen "void *cookie" "int (*writefn)(void *, const char *, int)"
.Sh DESCRIPTION
The
.Fn funopen
function
associates a stream with up to four
.Dq Tn I/O No functions .
Either
.Fa readfn
or
.Fa writefn
must be specified;
the others can be given as an appropriately-typed
.Dv NULL
pointer.
These
.Tn I/O
functions will be used to read, write, seek and
close the new stream.
.Pp
In general, omitting a function means that any attempt to perform the
associated operation on the resulting stream will fail.
If the close function is omitted, closing the stream will flush
any buffered output and then succeed.
.Pp
The calling conventions of
.Fa readfn ,
.Fa writefn ,
.Fa seekfn
and
.Fa closefn
must match those, respectively, of
.Xr read 2 ,
.Xr write 2 ,
.Xr lseek 2 ,
and
.Xr close 2
with the single exception that they are passed the
.Fa cookie
argument specified to
.Fn funopen
in place of the traditional file descriptor argument.
.Pp
Read and write
.Tn I/O
functions are allowed to change the underlying buffer
on fully buffered or line buffered streams by calling
.Xr setvbuf 3 .
They are also not required to completely fill or empty the buffer.
They are not, however, allowed to change streams from unbuffered to buffered
or to change the state of the line buffering flag.
They must also be prepared to have read or write calls occur on buffers other
than the one most recently specified.
.Pp
All user
.Tn I/O
functions can report an error by returning \-1.
Additionally, all of the functions should set the external variable
.Va errno
appropriately if an error occurs.
.Pp
An error on
.Fn closefn
does not keep the stream open.
.Pp
As a convenience, the include file
.In stdio.h
defines the macros
.Fn fropen
and
.Fn fwopen
as calls to
.Fn funopen
with only a read or write function specified.
.Sh RETURN VALUES
Upon successful completion,
.Fn funopen
returns a
.Dv FILE
pointer.
Otherwise,
.Dv NULL
is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EINVAL
The
.Fn funopen
function
was called without either a read or write function.
The
.Fn funopen
function
may also fail and set
.Va errno
for any of the errors
specified for the routine
.Xr malloc 3 .
.El
.Sh SEE ALSO
.Xr fcntl 2 ,
.Xr open 2 ,
.Xr fclose 3 ,
.Xr fopen 3 ,
.Xr fseek 3 ,
.Xr setbuf 3
.Sh HISTORY
The
.Fn funopen
functions first appeared in
.Bx 4.4 .
.Sh BUGS
The
.Fn funopen
function
may not be portable to systems other than
.Bx .
.Pp
On
.Fx ,
.Ox
and
.Dx
the
.Fn funopen
interface erroneously assumes that
.Vt fpos_t
is an integral type, and uses it in the
.Fa seekfn
hook; but because code using a
.Fa seekfn
hook will fail to build on systems where
.Vt fpos_t
is a struct, and it will need to be slightly fixed anyway, the
implementation provided by libbsd (in the same way as
.Nx )
uses the correct
.Vt off_t
types.
......@@ -51,6 +51,7 @@ libbsd_la_SOURCES = \
fmtcheck.c \
fparseln.c \
fpurge.c \
funopen.c \
getpeereid.c \
hash/md5.c \
hash/md5hl.c \
......
/*
* Copyright © 2011, 2013 Guillem Jover
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include <sys/types.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#ifdef HAVE_FOPENCOOKIE
struct funopen_cookie {
void *orig_cookie;
int (*readfn)(void *cookie, char *buf, int size);
int (*writefn)(void *cookie, const char *buf, int size);
off_t (*seekfn)(void *cookie, off_t offset, int whence);
int (*closefn)(void *cookie);
};
static ssize_t
funopen_read(void *cookie, char *buf, size_t size)
{
struct funopen_cookie *cookiewrap = cookie;
if (cookiewrap->readfn == NULL) {
errno = EBADF;
return -1;
}
return cookiewrap->readfn(cookiewrap->orig_cookie, buf, size);
}
static ssize_t
funopen_write(void *cookie, const char *buf, size_t size)
{
struct funopen_cookie *cookiewrap = cookie;
if (cookiewrap->writefn == NULL)
return EOF;
return cookiewrap->writefn(cookiewrap->orig_cookie, buf, size);
}
static int
funopen_seek(void *cookie, off64_t *offset, int whence)
{
struct funopen_cookie *cookiewrap = cookie;
off_t soff = *offset;
if (cookiewrap->seekfn == NULL) {
errno = ESPIPE;
return -1;
}
soff = cookiewrap->seekfn(cookiewrap->orig_cookie, soff, whence);
*offset = soff;
return *offset;
}
static int
funopen_close(void *cookie)
{
struct funopen_cookie *cookiewrap = cookie;
int rc;
if (cookiewrap->closefn == NULL)
return 0;
rc = cookiewrap->closefn(cookiewrap->orig_cookie);
free(cookiewrap);
return rc;
}
FILE *
funopen(const void *cookie,
int (*readfn)(void *cookie, char *buf, int size),
int (*writefn)(void *cookie, const char *buf, int size),
off_t (*seekfn)(void *cookie, off_t offset, int whence),
int (*closefn)(void *cookie))
{
struct funopen_cookie *cookiewrap;
cookie_io_functions_t funcswrap = {
.read = funopen_read,
.write = funopen_write,
.seek = funopen_seek,
.close = funopen_close,
};
const char *mode;
if (readfn) {
if (writefn == NULL)
mode = "r";
else
mode = "r+";
} else if (writefn) {
mode = "w";
} else {
errno = EINVAL;
return NULL;
}
cookiewrap = malloc(sizeof(*cookiewrap));
if (cookiewrap == NULL)
return NULL;
cookiewrap->orig_cookie = (void *)cookie;
cookiewrap->readfn = readfn;
cookiewrap->writefn = writefn;
cookiewrap->seekfn = seekfn;
cookiewrap->closefn = closefn;
return fopencookie(cookiewrap, mode, funcswrap);
}
#else
#error "Function funopen() needs to be ported."
#endif
......@@ -110,3 +110,7 @@ LIBBSD_0.6 {
/* Exported to cope with the constructor+dlopen+threads mess. */
setproctitle_init;
} LIBBSD_0.5;
LIBBSD_0.7 {
funopen;
} LIBBSD_0.6;
endian
fgetln
funopen
headers
humanize
overlay
......
......@@ -13,11 +13,13 @@ check_PROGRAMS = \
endian \
humanize \
fgetln \
funopen \
proctitle \
$(nil)
humanize_LDFLAGS = $(top_builddir)/src/libbsd.la
fgetln_LDFLAGS = $(top_builddir)/src/libbsd.la
funopen_LDFLAGS = $(top_builddir)/src/libbsd.la
proctitle_LDFLAGS = \
-Wl,-u,libbsd_init_func \
$(top_builddir)/src/libbsd-ctor.a \
......
/*
* Copyright © 2013 Guillem Jover <guillem@hadrons.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#define ARRAY_SIZE 100
#define TEST_SIZE 50
struct test_cookie {
char array[ARRAY_SIZE];
int index;
};
int
test_readfn(void *cookie, char *buf, int size)
{
struct test_cookie *tc = cookie;
int left_size = sizeof(tc->array) - tc->index;
if (left_size < 0)
size = 0;
else if (left_size < size)
size = left_size;
if (size > 0) {
memcpy(buf, tc->array + tc->index, size);
tc->index += size;
}
return size;
}
int
test_writefn(void *cookie, const char *buf, int size)
{
struct test_cookie *tc = cookie;
int left_size = sizeof(tc->array) - tc->index;
if (left_size < 0)
size = 0;
else if (left_size < size)
size = left_size;
if (size > 0) {
memcpy(tc->array + tc->index, buf, size);
tc->index += size;
}
return size;
}
off_t
test_seekfn(void *cookie, off_t offset, int whence)
{
struct test_cookie *tc = cookie;
switch (whence) {
case SEEK_SET:
tc->index = offset;
break;
case SEEK_CUR:
tc->index += offset;
break;
case SEEK_END:
tc->index = sizeof(tc->array) + offset;
break;
}
return tc->index;
}
int
test_closefn(void *cookie)
{
struct test_cookie *tc = cookie;
memset(tc->array, 0x7f, sizeof(tc->array));
return 0;
}
int
main(int argc, char **argv)
{
struct test_cookie tc;
char data[ARRAY_SIZE];
FILE *fp;
size_t i;
/* Test invalid hooks. */
fp = funopen(&tc, NULL, NULL, NULL, NULL);
assert(fp == NULL);
assert(errno == EINVAL);
/* Test read-only file. */
tc.index = 0;
for (i = 0; i < sizeof(tc.array); i++)
tc.array[i] = i;
fp = fropen(&tc, test_readfn);
assert(fp);
assert(fread(data, 1, TEST_SIZE, fp) == TEST_SIZE);
assert(memcmp(tc.array, data, TEST_SIZE) == 0);
assert(fwrite(data, 1, TEST_SIZE, fp) == 0);
assert(fclose(fp) == 0);
/* Test write-only file. */
memset(&tc, 0, sizeof(tc));
fp = fwopen(&tc, test_writefn);
assert(fp);
setvbuf(fp, NULL, _IONBF, 0);
assert(fwrite(data, 1, TEST_SIZE, fp) == TEST_SIZE);
assert(memcmp(tc.array, data, TEST_SIZE) == 0);
assert(fread(data, 1, TEST_SIZE, fp) == 0);
assert(fclose(fp) == 0);
/* Test seekable file. */
memset(&tc, 0, sizeof(tc));
fp = funopen(&tc, test_readfn, test_writefn, test_seekfn, NULL);
assert(fp);
setvbuf(fp, NULL, _IONBF, 0);
assert(fwrite(data, 1, TEST_SIZE, fp) == TEST_SIZE);
assert(fseek(fp, 0L, SEEK_SET) == 0);
assert(fwrite(data, 1, ARRAY_SIZE, fp) == ARRAY_SIZE);
assert(memcmp(tc.array, data, ARRAY_SIZE) == 0);
assert(fread(data, 1, TEST_SIZE, fp) == 0);
assert(fclose(fp) == 0);
/* Test close hook. */
memset(&tc, 0, sizeof(tc));
fp = funopen(&tc, test_readfn, test_writefn, NULL, test_closefn);
assert(fclose(fp) == 0);
for (i = 0; i < sizeof(tc.array); i++)
assert(tc.array[i] == 0x7f);
return 0;
}
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