kern_descrip.c

MIPS处理器的bootloader,龙芯就是用的修改过的PMON2

}

/*
 * Allocate a file descriptor for the process.
 */
int fdexpand;

int
fdalloc(p, want, result)
	struct proc *p;
	int want;
	int *result;
{
	register struct filedesc *fdp = p->p_fd;
	register int i; 
	int lim;
#ifndef PMON
	int last;
	int nfiles;
	struct file **newofile;
	char *newofileflags;
#endif

	/*
	 * Search for a free descriptor starting at the higher
	 * of want or fd_freefile.  If that fails, consider
	 * expanding the ofile array.
	 */
#ifdef NOTUSED_BY_PMON
	lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
#else
	lim = maxfiles;
#endif
#ifndef PMON
	for (;;) {
		last = min(fdp->fd_nfiles, lim);
		if ((i = want) < fdp->fd_freefile)
			i = fdp->fd_freefile;
		for (; i < last; i++) {
			if (fdp->fd_ofiles[i] == NULL) {
				fd_used(fdp, i);
				if (want <= fdp->fd_freefile)
					fdp->fd_freefile = i;
				*result = i;
				return (0);
			}
		}

		/*
		 * No space in current array.  Expand?
		 */
		if (fdp->fd_nfiles >= lim)
			return (EMFILE);
		if (fdp->fd_nfiles < NDEXTENT)
			nfiles = NDEXTENT;
		else
			nfiles = 2 * fdp->fd_nfiles;
		nfiles = min(lim, nfiles);
		MALLOC(newofile, struct file **, nfiles * OFILESIZE,
		    M_FILEDESC, M_WAITOK);
		newofileflags = (char *) &newofile[nfiles];
		/*
		 * Copy the existing ofile and ofileflags arrays
		 * and zero the new portion of each array.
		 */
		bcopy(fdp->fd_ofiles, newofile,
			(i = sizeof(struct file *) * fdp->fd_nfiles));
		bzero((char *)newofile + i, nfiles * sizeof(struct file *) - i);
		bcopy(fdp->fd_ofileflags, newofileflags,
			(i = sizeof(char) * fdp->fd_nfiles));
		bzero(newofileflags + i, nfiles * sizeof(char) - i);
		if (fdp->fd_nfiles > NDFILE)
			FREE(fdp->fd_ofiles, M_FILEDESC);
		fdp->fd_ofiles = newofile;
		fdp->fd_ofileflags = newofileflags;
		fdp->fd_nfiles = nfiles;
		fdexpand++;
	}
#else
	i = open("/dev/socket", 0, 0);
	if (i > 0) {
	   fd_used(fdp, i);
	   *result = i;
	   return (0);
	}
	return (EMFILE);
#endif
}

/*
 * Check to see whether n user file descriptors
 * are available to the process p.
 */
int
fdavail(p, n)
	struct proc *p;
	register int n;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file **fpp;
	register int i, lim;

#ifdef NOTUSED_BY_PMON
	lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
#else
	lim = NDFILE;
#endif
	if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
		return (1);
	fpp = &fdp->fd_ofiles[fdp->fd_freefile];
	for (i = min(lim, fdp->fd_nfiles) - fdp->fd_freefile; --i >= 0; fpp++)
		if (*fpp == NULL && --n <= 0)
			return (1);
	return (0);
}

/*
 * Create a new open file structure and allocate
 * a file decriptor for the process that refers to it.
 */
int
falloc(p, resultfp, resultfd)
	register struct proc *p;
	struct file **resultfp;
	int *resultfd;
{
	register struct file *fp, *fq;
	int error, i;

	if ((error = fdalloc(p, 0, &i)) != 0)
		return (error);
	if (nfiles >= maxfiles) {
		tablefull("file");
		return (ENFILE);
	}
	/*
	 * Allocate a new file descriptor.
	 * If the process has file descriptor zero open, add to the list
	 * of open files at that point, otherwise put it at the front of
	 * the list of open files.
	 */
	nfiles++;
	MALLOC(fp, struct file *, sizeof(struct file), M_FILE, M_WAITOK);
	bzero(fp, sizeof(struct file));
	if ((fq = p->p_fd->fd_ofiles[0]) != NULL) {
		LIST_INSERT_AFTER(fq, fp, f_list);
	} else {
		LIST_INSERT_HEAD(&filehead, fp, f_list);
	}
	p->p_fd->fd_ofiles[i] = fp;
	fp->f_count = 1;
	fp->f_cred = p->p_ucred;
	crhold(fp->f_cred);
	if (resultfp)
		*resultfp = fp;
	if (resultfd)
		*resultfd = i;
	return (0);
}

/*
 * Free a file descriptor.
 */
void
ffree(fp)
	register struct file *fp;
{
	LIST_REMOVE(fp, f_list);
	crfree(fp->f_cred);
#ifdef DIAGNOSTIC
	fp->f_count = 0;
#endif
	nfiles--;
	FREE(fp, M_FILE);
}

/*
 * Build a new filedesc structure.
 */
struct filedesc *
fdinit(p)
	struct proc *p;
{
	register struct filedesc0 *newfdp;
	register struct filedesc *fdp = p->p_fd;
	extern int cmask;

	MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0),
	    M_FILEDESC, M_WAITOK);
	bzero(newfdp, sizeof(struct filedesc0));
	newfdp->fd_fd.fd_cdir = fdp->fd_cdir;
#ifndef PMON
	VREF(newfdp->fd_fd.fd_cdir);
#endif
	newfdp->fd_fd.fd_rdir = fdp->fd_rdir;
#ifndef PMON
	if (newfdp->fd_fd.fd_rdir)
		VREF(newfdp->fd_fd.fd_rdir);
#endif

	/* Create the file descriptor table. */
	newfdp->fd_fd.fd_refcnt = 1;
	newfdp->fd_fd.fd_cmask = cmask;
	newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
	newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
	newfdp->fd_fd.fd_nfiles = NDFILE;

	newfdp->fd_fd.fd_freefile = 0;
	newfdp->fd_fd.fd_lastfile = 0;

	return (&newfdp->fd_fd);
}

/*
 * Share a filedesc structure.
 */
struct filedesc *
fdshare(p)
	struct proc *p;
{
	p->p_fd->fd_refcnt++;
	return (p->p_fd);
}

/*
 * Copy a filedesc structure.
 */
struct filedesc *
fdcopy(p)
	struct proc *p;
{
	register struct filedesc *newfdp, *fdp = p->p_fd;
	register struct file **fpp;
	register int i;

	MALLOC(newfdp, struct filedesc *, sizeof(struct filedesc0),
	    M_FILEDESC, M_WAITOK);
	bcopy(fdp, newfdp, sizeof(struct filedesc));
#ifndef PMON
	VREF(newfdp->fd_cdir);
	if (newfdp->fd_rdir)
		VREF(newfdp->fd_rdir);
#endif
	newfdp->fd_refcnt = 1;

	/*
	 * If the number of open files fits in the internal arrays
	 * of the open file structure, use them, otherwise allocate
	 * additional memory for the number of descriptors currently
	 * in use.
	 */
	if (newfdp->fd_lastfile < NDFILE) {
		newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles;
		newfdp->fd_ofileflags =
		    ((struct filedesc0 *) newfdp)->fd_dfileflags;
		i = NDFILE;
	} else {
		/*
		 * Compute the smallest multiple of NDEXTENT needed
		 * for the file descriptors currently in use,
		 * allowing the table to shrink.
		 */
		i = newfdp->fd_nfiles;
		while (i >= 2 * NDEXTENT && i > newfdp->fd_lastfile * 2)
			i /= 2;
		MALLOC(newfdp->fd_ofiles, struct file **, i * OFILESIZE,
		    M_FILEDESC, M_WAITOK);
		newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i];
	}
	newfdp->fd_nfiles = i;
	bcopy(fdp->fd_ofiles, newfdp->fd_ofiles, i * sizeof(struct file **));
	bcopy(fdp->fd_ofileflags, newfdp->fd_ofileflags, i * sizeof(char));
	fpp = newfdp->fd_ofiles;
	for (i = newfdp->fd_lastfile; i >= 0; i--, fpp++)
		if (*fpp != NULL) {
			/*
			 * XXX Gruesome hack. If count gets too high, fail
			 * to copy an fd, since fdcopy()'s callers do not
			 * permit it to indicate failure yet.
			 */
			if ((*fpp)->f_count == LONG_MAX-2)
				*fpp = NULL;
			else
				(*fpp)->f_count++;
		}
	return (newfdp);
}

/*
 * Release a filedesc structure.
 */
void
fdfree(p)
	struct proc *p;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file **fpp, *fp;
	register int i;

	if (--fdp->fd_refcnt > 0)
		return;
	fpp = fdp->fd_ofiles;
	for (i = fdp->fd_lastfile; i >= 0; i--, fpp++) {
		fp = *fpp;
		if (fp != NULL) {
			*fpp = NULL;
			(void) closef(fp, p);
		}
	}
	p->p_fd = NULL;
	if (fdp->fd_nfiles > NDFILE)
		FREE(fdp->fd_ofiles, M_FILEDESC);
#ifndef PMON
	vrele(fdp->fd_cdir);
	if (fdp->fd_rdir)
		vrele(fdp->fd_rdir);
#endif
	FREE(fdp, M_FILEDESC);
}

/*
 * Internal form of close.
 * Decrement reference count on file structure.
 * Note: p may be NULL when closing a file
 * that was being passed in a message.
 */
int
closef(fp, p)
	register struct file *fp;
	register struct proc *p;
{
#ifndef PMON
	struct vnode *vp;
	struct flock lf;
#endif
	int error;

	if (fp == NULL)
		return (0);
	/*
	 * POSIX record locking dictates that any close releases ALL
	 * locks owned by this process.  This is handled by setting
	 * a flag in the unlock to free ONLY locks obeying POSIX
	 * semantics, and not to free BSD-style file locks.
	 * If the descriptor was in a message, POSIX-style locks
	 * aren't passed with the descriptor.
	 */
#ifndef PMON
	if (p && (p->p_flag & P_ADVLOCK) && fp->f_type == DTYPE_VNODE) {
		lf.l_whence = SEEK_SET;
		lf.l_start = 0;
		lf.l_len = 0;
		lf.l_type = F_UNLCK;
		vp = (struct vnode *)fp->f_data;
		(void) VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_POSIX);
	}
#endif
	if (--fp->f_count > 0)
		return (0);
	if (fp->f_count < 0)
		panic("closef: count < 0");
#ifndef PMON
	if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
		lf.l_whence = SEEK_SET;
		lf.l_start = 0;
		lf.l_len = 0;
		lf.l_type = F_UNLCK;
		vp = (struct vnode *)fp->f_data;
		(void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
	}
#endif
	if (fp->f_ops)
		error = (*fp->f_ops->fo_close)(fp, p);
	else
		error = 0;
	ffree(fp);
	return (error);
}

#ifdef NOTUSED_BY_PMON
/*
 * Apply an advisory lock on a file descriptor.
 *
 * Just attempt to get a record lock of the requested type on
 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
 */
/* ARGSUSED */
int
sys_flock(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_flock_args /* {
		syscallarg(int) fd;
		syscallarg(int) how;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	int how = SCARG(uap, how);
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	struct vnode *vp;
	struct flock lf;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	if (fp->f_type != DTYPE_VNODE)
		return (EOPNOTSUPP);
	vp = (struct vnode *)fp->f_data;
	lf.l_whence = SEEK_SET;
	lf.l_start = 0;
	lf.l_len = 0;
	if (how & LOCK_UN) {
		lf.l_type = F_UNLCK;
		fp->f_flag &= ~FHASLOCK;
		return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK));
	}
	if (how & LOCK_EX)
		lf.l_type = F_WRLCK;
	else if (how & LOCK_SH)
		lf.l_type = F_RDLCK;
	else
		return (EINVAL);
	fp->f_flag |= FHASLOCK;
	if (how & LOCK_NB)
		return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK));
	return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT));
}

/*
 * File Descriptor pseudo-device driver (/dev/fd/).
 *
 * Opening minor device N dup()s the file (if any) connected to file
 * descriptor N belonging to the calling process.  Note that this driver
 * consists of only the ``open()'' routine, because all subsequent
 * references to this file will be direct to the other driver.
 */
/* ARGSUSED */
int
filedescopen(dev, mode, type, p)
	dev_t dev;
	int mode, type;
	struct proc *p;
{

	/*
	 * XXX Kludge: set curproc->p_dupfd to contain the value of the
	 * the file descriptor being sought for duplication. The error 
	 * return ensures that the vnode for this device will be released
	 * by vn_open. Open will detect this special error and take the
	 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
	 * will simply report the error.
	 */
	p->p_dupfd = minor(dev);
	return (ENODEV);
}

/*
 * Duplicate the specified descriptor to a free descriptor.
 */
int
dupfdopen(fdp, indx, dfd, mode, error)
	register struct filedesc *fdp;
	register int indx, dfd;
	int mode;
	int error;
{
	register struct file *wfp;
	struct file *fp;

	/*
	 * If the to-be-dup'd fd number is greater than the allowed number
	 * of file descriptors, or the fd to be dup'd has already been
	 * closed, reject.  Note, check for new == old is necessary as
	 * falloc could allocate an already closed to-be-dup'd descriptor
	 * as the new descriptor.
	 */
	fp = fdp->fd_ofiles[indx];
	if ((u_int)dfd >= fdp->fd_nfiles ||
	    (wfp = fdp->fd_ofiles[dfd]) == NULL || fp == wfp)
		return (EBADF);

	/*
	 * There are two cases of interest here.
	 *
	 * For ENODEV simply dup (dfd) to file descriptor
	 * (indx) and return.
	 *
	 * For ENXIO steal away the file structure from (dfd) and
	 * store it in (indx).  (dfd) is effectively closed by
	 * this operation.
	 *
	 * Any other error code is just returned.
	 */
	switch (error) {
	case ENODEV:
		/*
		 * Check that the mode the file is being opened for is a
		 * subset of the mode of the existing descriptor.
		 */
		if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag)
			return (EACCES);
		if (wfp->f_count == LONG_MAX-2)
			return (EDEADLK);
		fdp->fd_ofiles[indx] = wfp;
		fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
		wfp->f_count++;
		fd_used(fdp, indx);
		return (0);

	case ENXIO:
		/*
		 * Steal away the file pointer from dfd, and stuff it into indx.
		 */
		fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
		fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
		fdp->fd_ofiles[dfd] = NULL;
		fdp->fd_ofileflags[dfd] = 0;
		/*
		 * Complete the clean up of the filedesc structure by
		 * recomputing the various hints.
		 */
		fd_used(fdp, indx);
		fd_unused(fdp, dfd);
		return (0);

	default:
		return (error);
	}
	/* NOTREACHED */
}

/*
 * Close any files on exec?
 */
void
fdcloseexec(p)
	struct proc *p;
{
	register struct filedesc *fdp = p->p_fd;
	register int fd;

	for (fd = 0; fd <= fdp->fd_lastfile; fd++)
		if (fdp->fd_ofileflags[fd] & UF_EXCLOSE)
			(void) fdrelease(p, fd);
}
#endif /* NOTUSED_BY_PMON */