cpython-withatomic / Modules / fcntlmodule.c

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/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
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provided that the above copyright notice appear in all copies and that
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permission.

While CWI is the initial source for this software, a modified version
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(CNRI) at the Internet address ftp://ftp.python.org.

STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
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PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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******************************************************************/

/* fcntl module */

#include "allobjects.h"
#include "modsupport.h"

#include <fcntl.h>


/* fcntl(fd, opt, [arg]) */

static object *
fcntl_fcntl(self, args)
	object *self; /* Not used */
	object *args;
{
	int fd;
	int code;
	int arg;
	int ret;
	char *str;
	int len;
	char buf[1024];

	if (getargs(args, "(iis#)", &fd, &code, &str, &len)) {
		if (len > sizeof buf) {
			err_setstr(ValueError, "fcntl string arg too long");
			return NULL;
		}
		memcpy(buf, str, len);
		BGN_SAVE
		ret = fcntl(fd, code, buf);
		END_SAVE
		if (ret < 0) {
			err_errno(IOError);
			return NULL;
		}
		return newsizedstringobject(buf, len);
	}

	err_clear();
	if (getargs(args, "(ii)", &fd, &code))
		arg = 0;
	else {
		err_clear();
		if (!getargs(args, "(iii)", &fd, &code, &arg))
			return NULL;
	}
	BGN_SAVE
	ret = fcntl(fd, code, arg);
	END_SAVE
	if (ret < 0) {
		err_errno(IOError);
		return NULL;
	}
	return newintobject((long)ret);
}


/* ioctl(fd, opt, [arg]) */

static object *
fcntl_ioctl(self, args)
	object *self; /* Not used */
	object *args;
{
	int fd;
	int code;
	int arg;
	int ret;
	char *str;
	int len;
	char buf[1024];

	if (getargs(args, "(iis#)", &fd, &code, &str, &len)) {
		if (len > sizeof buf) {
			err_setstr(ValueError, "ioctl string arg too long");
			return NULL;
		}
		memcpy(buf, str, len);
		BGN_SAVE
		ret = ioctl(fd, code, buf);
		END_SAVE
		if (ret < 0) {
			err_errno(IOError);
			return NULL;
		}
		return newsizedstringobject(buf, len);
	}

	err_clear();
	if (getargs(args, "(ii)", &fd, &code))
		arg = 0;
	else {
		err_clear();
		if (!getargs(args, "(iii)", &fd, &code, &arg))
			return NULL;
	}
	BGN_SAVE
	ret = ioctl(fd, code, arg);
	END_SAVE
	if (ret < 0) {
		err_errno(IOError);
		return NULL;
	}
	return newintobject((long)ret);
}


/* flock(fd, operation) */

static object *
fcntl_flock(self, args)
	object *self; /* Not used */
	object *args;
{
	int fd;
	int code;
	int ret;
	FILE *f;

	if (!getargs(args, "(ii)", &fd, &code))
		return NULL;

	BGN_SAVE
#ifdef HAVE_FLOCK
	ret = flock(fd, code);
#else

#ifndef LOCK_SH
#define LOCK_SH		1	/* shared lock */
#define LOCK_EX		2	/* exclusive lock */
#define LOCK_NB		4	/* don't block when locking */
#define LOCK_UN		8	/* unlock */
#endif
	{
		struct flock l;
		if (code == LOCK_UN)
			l.l_type = F_UNLCK;
		else if (code & LOCK_SH)
			l.l_type = F_RDLCK;
		else if (code & LOCK_EX)
			l.l_type = F_WRLCK;
		else {
			err_setstr(ValueError, "unrecognized flock argument");
			return NULL;
		}
		l.l_whence = l.l_start = l.l_len = 0;
		ret = fcntl(fd, (code & LOCK_NB) ? F_SETLK : F_SETLKW, &l);
	}
#endif /* HAVE_FLOCK */
	END_SAVE
	if (ret < 0) {
		err_errno(IOError);
		return NULL;
	}
	INCREF(None);
	return None;
}

/* lockf(fd, operation) */
static object *
fcntl_lockf(self, args)
	object *self; /* Not used */
	object *args;
{
	int fd, code, len = 0, start = 0, whence = 0, ret;
	FILE *f;

	if (!PyArg_ParseTuple(args, "ii|iii", &fd, &code, &len, 
			       &start, &whence))
	    return NULL;

	BGN_SAVE
#ifndef LOCK_SH
#define LOCK_SH		1	/* shared lock */
#define LOCK_EX		2	/* exclusive lock */
#define LOCK_NB		4	/* don't block when locking */
#define LOCK_UN		8	/* unlock */
#endif
	{
		struct flock l;
		if (code == LOCK_UN)
			l.l_type = F_UNLCK;
		else if (code & LOCK_SH)
			l.l_type = F_RDLCK;
		else if (code & LOCK_EX)
			l.l_type = F_WRLCK;
		else {
			err_setstr(ValueError, "unrecognized flock argument");
			return NULL;
		}
		l.l_len = len;
		l.l_start = start;
		l.l_whence = whence;
		ret = fcntl(fd, (code & LOCK_NB) ? F_SETLK : F_SETLKW, &l);
	}
	END_SAVE
	if (ret < 0) {
		err_errno(IOError);
		return NULL;
	}
	INCREF(None);
	return None;
}

/* List of functions */

static struct methodlist fcntl_methods[] = {
	{"fcntl",	fcntl_fcntl},
	{"ioctl",	fcntl_ioctl},
	{"flock",	fcntl_flock},
	{"lockf",       fcntl_lockf, 1},
	{NULL,		NULL}		/* sentinel */
};


/* Module initialisation */

void
initfcntl()
{
	object *m, *d;

	/* Create the module and add the functions */
	m = initmodule("fcntl", fcntl_methods);

	/* Add some symbolic constants to the module */
	d = getmoduledict(m);

	/* Check for errors */
	if (err_occurred())
		fatal("can't initialize module fcntl");
}
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