freebsd-dev/sys/miscfs/procfs/procfs_subr.c
2000-04-29 15:36:14 +00:00

412 lines
9.7 KiB
C

/*
* Copyright (c) 1993 Jan-Simon Pendry
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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.
*
* @(#)procfs_subr.c 8.6 (Berkeley) 5/14/95
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <miscfs/procfs/procfs.h>
static struct pfsnode *pfshead;
static int pfsvplock;
/*
* allocate a pfsnode/vnode pair. the vnode is
* referenced, but not locked.
*
* the pid, pfs_type, and mount point uniquely
* identify a pfsnode. the mount point is needed
* because someone might mount this filesystem
* twice.
*
* all pfsnodes are maintained on a singly-linked
* list. new nodes are only allocated when they cannot
* be found on this list. entries on the list are
* removed when the vfs reclaim entry is called.
*
* a single lock is kept for the entire list. this is
* needed because the getnewvnode() function can block
* waiting for a vnode to become free, in which case there
* may be more than one process trying to get the same
* vnode. this lock is only taken if we are going to
* call getnewvnode, since the kernel itself is single-threaded.
*
* if an entry is found on the list, then call vget() to
* take a reference. this is done because there may be
* zero references to it and so it needs to removed from
* the vnode free list.
*/
int
procfs_allocvp(mp, vpp, pid, pfs_type)
struct mount *mp;
struct vnode **vpp;
long pid;
pfstype pfs_type;
{
struct proc *p = curproc; /* XXX */
struct pfsnode *pfs;
struct vnode *vp;
struct pfsnode **pp;
int error;
loop:
for (pfs = pfshead; pfs != 0; pfs = pfs->pfs_next) {
vp = PFSTOV(pfs);
if (pfs->pfs_pid == pid &&
pfs->pfs_type == pfs_type &&
vp->v_mount == mp) {
if (vget(vp, 0, p))
goto loop;
*vpp = vp;
return (0);
}
}
/*
* otherwise lock the vp list while we call getnewvnode
* since that can block.
*/
if (pfsvplock & PROCFS_LOCKED) {
pfsvplock |= PROCFS_WANT;
(void) tsleep((caddr_t) &pfsvplock, PINOD, "pfsavp", 0);
goto loop;
}
pfsvplock |= PROCFS_LOCKED;
/*
* Do the MALLOC before the getnewvnode since doing so afterward
* might cause a bogus v_data pointer to get dereferenced
* elsewhere if MALLOC should block.
*/
MALLOC(pfs, struct pfsnode *, sizeof(struct pfsnode), M_TEMP, M_WAITOK);
if ((error = getnewvnode(VT_PROCFS, mp, procfs_vnodeop_p, vpp)) != 0) {
FREE(pfs, M_TEMP);
goto out;
}
vp = *vpp;
vp->v_data = pfs;
pfs->pfs_next = 0;
pfs->pfs_pid = (pid_t) pid;
pfs->pfs_type = pfs_type;
pfs->pfs_vnode = vp;
pfs->pfs_flags = 0;
pfs->pfs_lockowner = 0;
pfs->pfs_fileno = PROCFS_FILENO(pid, pfs_type);
switch (pfs_type) {
case Proot: /* /proc = dr-xr-xr-x */
pfs->pfs_mode = (VREAD|VEXEC) |
(VREAD|VEXEC) >> 3 |
(VREAD|VEXEC) >> 6;
vp->v_type = VDIR;
vp->v_flag = VROOT;
break;
case Pcurproc: /* /proc/curproc = lr--r--r-- */
pfs->pfs_mode = (VREAD) |
(VREAD >> 3) |
(VREAD >> 6);
vp->v_type = VLNK;
break;
case Pproc:
pfs->pfs_mode = (VREAD|VEXEC) |
(VREAD|VEXEC) >> 3 |
(VREAD|VEXEC) >> 6;
vp->v_type = VDIR;
break;
case Pfile:
pfs->pfs_mode = (VREAD|VEXEC) |
(VREAD|VEXEC) >> 3 |
(VREAD|VEXEC) >> 6;
vp->v_type = VLNK;
break;
case Pmem:
pfs->pfs_mode = (VREAD|VWRITE) |
(VREAD) >> 3;;
vp->v_type = VREG;
break;
case Pregs:
case Pfpregs:
case Pdbregs:
pfs->pfs_mode = (VREAD|VWRITE);
vp->v_type = VREG;
break;
case Pctl:
case Pnote:
case Pnotepg:
pfs->pfs_mode = (VWRITE);
vp->v_type = VREG;
break;
case Ptype:
case Pmap:
case Pstatus:
case Pcmdline:
case Prlimit:
pfs->pfs_mode = (VREAD) |
(VREAD >> 3) |
(VREAD >> 6);
vp->v_type = VREG;
break;
default:
panic("procfs_allocvp");
}
/* add to procfs vnode list */
for (pp = &pfshead; *pp; pp = &(*pp)->pfs_next)
continue;
*pp = pfs;
out:
pfsvplock &= ~PROCFS_LOCKED;
if (pfsvplock & PROCFS_WANT) {
pfsvplock &= ~PROCFS_WANT;
wakeup((caddr_t) &pfsvplock);
}
return (error);
}
int
procfs_freevp(vp)
struct vnode *vp;
{
struct pfsnode **pfspp;
struct pfsnode *pfs = VTOPFS(vp);
for (pfspp = &pfshead; *pfspp != 0; pfspp = &(*pfspp)->pfs_next) {
if (*pfspp == pfs) {
*pfspp = pfs->pfs_next;
break;
}
}
FREE(vp->v_data, M_TEMP);
vp->v_data = 0;
return (0);
}
int
procfs_rw(ap)
struct vop_read_args *ap;
{
struct vnode *vp = ap->a_vp;
struct uio *uio = ap->a_uio;
struct proc *curp = uio->uio_procp;
struct pfsnode *pfs = VTOPFS(vp);
struct proc *p;
int rtval;
p = PFIND(pfs->pfs_pid);
if (p == 0)
return (EINVAL);
if (p->p_pid == 1 && securelevel > 0 && uio->uio_rw == UIO_WRITE)
return (EACCES);
while (pfs->pfs_lockowner) {
tsleep(&pfs->pfs_lockowner, PRIBIO, "pfslck", 0);
}
pfs->pfs_lockowner = curproc->p_pid;
switch (pfs->pfs_type) {
case Pnote:
case Pnotepg:
rtval = procfs_donote(curp, p, pfs, uio);
break;
case Pregs:
rtval = procfs_doregs(curp, p, pfs, uio);
break;
case Pfpregs:
rtval = procfs_dofpregs(curp, p, pfs, uio);
break;
case Pdbregs:
rtval = procfs_dodbregs(curp, p, pfs, uio);
break;
case Pctl:
rtval = procfs_doctl(curp, p, pfs, uio);
break;
case Pstatus:
rtval = procfs_dostatus(curp, p, pfs, uio);
break;
case Pmap:
rtval = procfs_domap(curp, p, pfs, uio);
break;
case Pmem:
rtval = procfs_domem(curp, p, pfs, uio);
break;
case Ptype:
rtval = procfs_dotype(curp, p, pfs, uio);
break;
case Pcmdline:
rtval = procfs_docmdline(curp, p, pfs, uio);
break;
case Prlimit:
rtval = procfs_dorlimit(curp, p, pfs, uio);
break;
default:
rtval = EOPNOTSUPP;
break;
}
pfs->pfs_lockowner = 0;
wakeup(&pfs->pfs_lockowner);
return rtval;
}
/*
* Get a string from userland into (buf). Strip a trailing
* nl character (to allow easy access from the shell).
* The buffer should be *buflenp + 1 chars long. vfs_getuserstr
* will automatically add a nul char at the end.
*
* Returns 0 on success or the following errors
*
* EINVAL: file offset is non-zero.
* EMSGSIZE: message is longer than kernel buffer
* EFAULT: user i/o buffer is not addressable
*/
int
vfs_getuserstr(uio, buf, buflenp)
struct uio *uio;
char *buf;
int *buflenp;
{
int xlen;
int error;
if (uio->uio_offset != 0)
return (EINVAL);
xlen = *buflenp;
/* must be able to read the whole string in one go */
if (xlen < uio->uio_resid)
return (EMSGSIZE);
xlen = uio->uio_resid;
if ((error = uiomove(buf, xlen, uio)) != 0)
return (error);
/* allow multiple writes without seeks */
uio->uio_offset = 0;
/* cleanup string and remove trailing newline */
buf[xlen] = '\0';
xlen = strlen(buf);
if (xlen > 0 && buf[xlen-1] == '\n')
buf[--xlen] = '\0';
*buflenp = xlen;
return (0);
}
vfs_namemap_t *
vfs_findname(nm, buf, buflen)
vfs_namemap_t *nm;
char *buf;
int buflen;
{
for (; nm->nm_name; nm++)
if (bcmp(buf, nm->nm_name, buflen+1) == 0)
return (nm);
return (0);
}
void
procfs_exit(struct proc *p)
{
struct pfsnode *pfs;
pid_t pid = p->p_pid;
/*
* The reason for this loop is not obvious -- basicly,
* procfs_freevp(), which is called via vgone() (eventually),
* removes the specified procfs node from the pfshead list.
* It does this by *pfsp = pfs->pfs_next, meaning that it
* overwrites the node. So when we do pfs = pfs->next, we
* end up skipping the node that replaces the one that was
* vgone'd. Since it may have been the last one on the list,
* it may also have been set to null -- but *our* pfs pointer,
* here, doesn't see this. So the loop starts from the beginning
* again.
*
* This is not a for() loop because the final event
* would be "pfs = pfs->pfs_next"; in the case where
* pfs is set to pfshead again, that would mean that
* pfshead is skipped over.
*
*/
pfs = pfshead;
while (pfs) {
if (pfs->pfs_pid == pid) {
vgone(PFSTOV(pfs));
pfs = pfshead;
} else
pfs = pfs->pfs_next;
}
}