Differential D27319 Diff 79872 head/sys/kern/kern_descrip.c

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head/sys/kern/kern_descrip.c

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* Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD).		* Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD).
*/		*/
int		int
kern_dup(struct thread *td, u_int mode, int flags, int old, int new)		kern_dup(struct thread *td, u_int mode, int flags, int old, int new)
{		{
struct filedesc *fdp;		struct filedesc *fdp;
struct filedescent oldfde, newfde;		struct filedescent oldfde, newfde;
struct proc *p;		struct proc *p;
struct file *delfp;		struct file delfp, oldfp;
u_long oioctls, nioctls;		u_long oioctls, nioctls;
int error, maxfd;		int error, maxfd;

p = td->td_proc;		p = td->td_proc;
fdp = p->p_fd;		fdp = p->p_fd;
oioctls = NULL;		oioctls = NULL;

MPASS((flags & ~(FDDUP_FLAG_CLOEXEC)) == 0);		MPASS((flags & ~(FDDUP_FLAG_CLOEXEC)) == 0);
Show All 23 Lines	if ((mode == FDDUP_FIXED \|\| mode == FDDUP_MUSTREPLACE) && old == new) {
td->td_retval[0] = new;		td->td_retval[0] = new;
if (flags & FDDUP_FLAG_CLOEXEC)		if (flags & FDDUP_FLAG_CLOEXEC)
fdp->fd_ofiles[new].fde_flags \|= UF_EXCLOSE;		fdp->fd_ofiles[new].fde_flags \|= UF_EXCLOSE;
error = 0;		error = 0;
goto unlock;		goto unlock;
}		}

oldfde = &fdp->fd_ofiles[old];		oldfde = &fdp->fd_ofiles[old];
if (!fhold(oldfde->fde_file))		oldfp = oldfde->fde_file;
		if (!fhold(oldfp))
goto unlock;		goto unlock;

/*		/*
* If the caller specified a file descriptor, make sure the file		* If the caller specified a file descriptor, make sure the file
* table is large enough to hold it, and grab it. Otherwise, just		* table is large enough to hold it, and grab it. Otherwise, just
* allocate a new descriptor the usual way.		* allocate a new descriptor the usual way.
*/		*/
switch (mode) {		switch (mode) {
case FDDUP_NORMAL:		case FDDUP_NORMAL:
case FDDUP_FCNTL:		case FDDUP_FCNTL:
if ((error = fdalloc(td, new, &new)) != 0) {		if ((error = fdalloc(td, new, &new)) != 0) {
fdrop(oldfde->fde_file, td);		fdrop(oldfp, td);
goto unlock;		goto unlock;
}		}
break;		break;
case FDDUP_MUSTREPLACE:		case FDDUP_MUSTREPLACE:
/* Target file descriptor must exist. */		/* Target file descriptor must exist. */
if (fget_locked(fdp, new) == NULL) {		if (fget_locked(fdp, new) == NULL) {
fdrop(oldfde->fde_file, td);		fdrop(oldfp, td);
goto unlock;		goto unlock;
}		}
break;		break;
case FDDUP_FIXED:		case FDDUP_FIXED:
if (new >= fdp->fd_nfiles) {		if (new >= fdp->fd_nfiles) {
/*		/*
* The resource limits are here instead of e.g.		* The resource limits are here instead of e.g.
* fdalloc(), because the file descriptor table may be		* fdalloc(), because the file descriptor table may be
* shared between processes, so we can't really use		* shared between processes, so we can't really use
* racct_add()/racct_sub(). Instead of counting the		* racct_add()/racct_sub(). Instead of counting the
* number of actually allocated descriptors, just put		* number of actually allocated descriptors, just put
* the limit on the size of the file descriptor table.		* the limit on the size of the file descriptor table.
*/		*/
#ifdef RACCT		#ifdef RACCT
if (RACCT_ENABLED()) {		if (RACCT_ENABLED()) {
error = racct_set_unlocked(p, RACCT_NOFILE, new + 1);		error = racct_set_unlocked(p, RACCT_NOFILE, new + 1);
if (error != 0) {		if (error != 0) {
error = EMFILE;		error = EMFILE;
fdrop(oldfde->fde_file, td);		fdrop(oldfp, td);
goto unlock;		goto unlock;
}		}
}		}
#endif		#endif
fdgrowtable_exp(fdp, new + 1);		fdgrowtable_exp(fdp, new + 1);
}		}
if (!fdisused(fdp, new))		if (!fdisused(fdp, new))
fdused(fdp, new);		fdused(fdp, new);
break;		break;
default:		default:
KASSERT(0, ("%s unsupported mode %d", __func__, mode));		KASSERT(0, ("%s unsupported mode %d", __func__, mode));
}		}

KASSERT(old != new, ("new fd is same as old"));		KASSERT(old != new, ("new fd is same as old"));

		/* Refetch oldfde because the table may have grown and old one freed. */
		oldfde = &fdp->fd_ofiles[old];
		KASSERT(oldfp == oldfde->fde_file,
		("fdt_ofiles shift from growth observed at fd %d",
		old));

newfde = &fdp->fd_ofiles[new];		newfde = &fdp->fd_ofiles[new];
delfp = newfde->fde_file;		delfp = newfde->fde_file;

nioctls = filecaps_copy_prep(&oldfde->fde_caps);		nioctls = filecaps_copy_prep(&oldfde->fde_caps);

/*		/*
* Duplicate the source descriptor.		* Duplicate the source descriptor.
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