NetBSD/sys/miscfs/procfs/procfs_vnops.c

870 lines
19 KiB
C

/*
* Copyright (c) 1993 The Regents of the University of California.
* Copyright (c) 1993 Jan-Simon Pendry
* 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.
*
* From:
* Id: procfs_vnops.c,v 4.2 1994/01/02 15:28:44 jsp Exp
*
* $Id: procfs_vnops.c,v 1.14 1994/01/28 07:03:41 cgd Exp $
*/
/*
* procfs vnode interface
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/resourcevar.h>
#include <sys/ptrace.h>
#include <miscfs/procfs/procfs.h>
#include <vm/vm.h> /* for page_size */
#include <machine/reg.h>
/*
* Vnode Operations.
*
*/
/*
* This is a list of the valid names in the
* process-specific sub-directories. It is
* used in procfs_lookup and procfs_readdir
*/
static struct pfsnames {
u_short d_namlen;
char d_name[PROCFS_NAMELEN];
pfstype d_pfstype;
} procent[] = {
#define N(s) sizeof(s)-1, s
/* namlen, nam, type */
{ N("."), Pproc },
{ N(".."), Proot },
{ N("file"), Pfile },
{ N("mem"), Pmem },
{ N("regs"), Pregs },
{ N("fpregs"), Pfpregs },
{ N("ctl"), Pctl },
{ N("status"), Pstatus },
{ N("note"), Pnote },
{ N("notepg"), Pnotepg },
#undef N
};
#define Nprocent (sizeof(procent)/sizeof(procent[0]))
#define PROCFS_XFILES 3 /* number of other entries, like "curproc" */
static pid_t atopid __P((const char *, u_int));
/*
* set things up for doing i/o on
* the pfsnode (vp). (vp) is locked
* on entry, and should be left locked
* on exit.
*
* for procfs we don't need to do anything
* in particular for i/o. all that is done
* is to support exclusive open on process
* memory images.
*/
procfs_open(vp, mode, cred, p)
struct vnode *vp;
int mode;
struct ucred *cred;
struct proc *p;
{
struct pfsnode *pfs = VTOPFS(vp);
switch (pfs->pfs_type) {
case Pmem:
if (PFIND(pfs->pfs_pid) == 0)
return (ENOENT); /* was ESRCH, jsp */
if ((pfs->pfs_flags & FWRITE) && (mode & O_EXCL) ||
(pfs->pfs_flags & O_EXCL) && (mode & FWRITE))
return (EBUSY);
if (mode & FWRITE)
pfs->pfs_flags = (mode & (FWRITE|O_EXCL));
return (0);
default:
break;
}
return (0);
}
/*
* close the pfsnode (vp) after doing i/o.
* (vp) is not locked on entry or exit.
*
* nothing to do for procfs other than undo
* any exclusive open flag (see _open above).
*/
procfs_close(vp, flag, cred, p)
struct vnode *vp;
int flag;
struct ucred *cred;
struct proc *p;
{
struct pfsnode *pfs = VTOPFS(vp);
switch (pfs->pfs_type) {
case Pmem:
if ((flag & FWRITE) && (pfs->pfs_flags & O_EXCL))
pfs->pfs_flags &= ~(FWRITE|O_EXCL);
break;
}
return (0);
}
/*
* do an ioctl operation on pfsnode (vp).
* (vp) is not locked on entry or exit.
*/
procfs_ioctl(vp, com, data, fflag, cred, p)
struct vnode *vp;
int com;
caddr_t data;
int fflag;
struct ucred *cred;
struct proc *p;
{
return (ENOTTY);
}
/*
* do block mapping for pfsnode (vp).
* since we don't use the buffer cache
* for procfs this function should never
* be called. in any case, it's not clear
* what part of the kernel ever makes use
* of this function. for sanity, this is the
* usual no-op bmap, although returning
* (EIO) would be a reasonable alternative.
*/
procfs_bmap(vp, bn, vpp, bnp)
struct vnode *vp;
daddr_t bn;
struct vnode **vpp;
daddr_t *bnp;
{
if (vpp != NULL)
*vpp = vp;
if (bnp != NULL)
*bnp = bn;
return (0);
}
/*
* _inactive is called when the pfsnode
* is vrele'd and the reference count goes
* to zero. (vp) will be on the vnode free
* list, so to get it back vget() must be
* used.
*
* for procfs, check if the process is still
* alive and if it isn't then just throw away
* the vnode by calling vgone(). this may
* be overkill and a waste of time since the
* chances are that the process will still be
* there and PFIND is not free.
*
* (vp) is not locked on entry or exit.
*/
procfs_inactive(vp, p)
struct vnode *vp;
struct proc *p;
{
struct pfsnode *pfs = VTOPFS(vp);
if (PFIND(pfs->pfs_pid) == 0)
vgone(vp);
return (0);
}
/*
* _reclaim is called when getnewvnode()
* wants to make use of an entry on the vnode
* free list. at this time the filesystem needs
* to free any private data and remove the node
* from any private lists.
*/
procfs_reclaim(vp)
struct vnode *vp;
{
int error;
error = procfs_freevp(vp);
return (error);
}
/*
* _print is used for debugging.
* just print a readable description
* of (vp).
*/
procfs_print(vp)
struct vnode *vp;
{
struct pfsnode *pfs = VTOPFS(vp);
printf("tag VT_PROCFS, pid %d, mode %x, flags %x\n",
pfs->pfs_pid,
pfs->pfs_mode, pfs->pfs_flags);
}
/*
* _abortop is called when operations such as
* rename and create fail. this entry is responsible
* for undoing any side-effects caused by the lookup.
* this will always include freeing the pathname buffer.
*/
procfs_abortop(ndp)
struct nameidata *ndp;
{
if ((ndp->ni_nameiop & (HASBUF | SAVESTART)) == HASBUF)
FREE(ndp->ni_pnbuf, M_NAMEI);
return (0);
}
/*
* generic entry point for unsupported operations
*/
procfs_badop()
{
return (EIO);
}
/*
* Invent attributes for pfsnode (vp) and store
* them in (vap).
* Directories lengths are returned as zero since
* any real length would require the genuine size
* to be computed, and nothing cares anyway.
*
* this is relatively minimal for procfs.
*/
procfs_getattr(vp, vap, cred, p)
struct vnode *vp;
struct vattr *vap;
struct ucred *cred;
struct proc *p;
{
struct pfsnode *pfs = VTOPFS(vp);
struct proc *procp;
int error;
/* start by zeroing out the attributes */
VATTR_NULL(vap);
/* next do all the common fields */
vap->va_type = vp->v_type;
vap->va_mode = pfs->pfs_mode;
vap->va_fileid = pfs->pfs_fileno;
vap->va_flags = 0;
vap->va_blocksize = page_size;
vap->va_bytes = vap->va_size = 0;
/*
* Make all times be current TOD.
* It would be possible to get the process start
* time from the p_stat structure, but there's
* no "file creation" time stamp anyway, and the
* p_stat structure is not addressible if u. gets
* swapped out for that process.
*/
microtime(&vap->va_ctime);
vap->va_atime = vap->va_mtime = vap->va_ctime;
error = 0;
if (pfs->pfs_type != Proot) {
/* check the process still exists */
procp = PFIND(pfs->pfs_pid);
if (procp == 0)
return (ENOENT);
/* most of the time we want these values */
vap->va_nlink = 1;
vap->va_uid = procp->p_ucred->cr_uid;
vap->va_gid = procp->p_ucred->cr_gid;
}
/*
* now do the object specific fields
*
* The size could be set from struct reg, but it's hardly
* worth the trouble, and it puts some (potentially) machine
* dependent data into this machine-independent code. If it
* becomes important then this function should break out into
* a per-file stat function in the corresponding .c file.
*/
switch (pfs->pfs_type) {
case Proot:
switch ((int)pfs->pfs_pid) {
case 0: /* /proc */
vap->va_nlink = 2;
vap->va_uid = 0;
vap->va_gid = 0;
vap->va_bytes = vap->va_size
= (maxproc + 1 + PROCFS_XFILES) * UIO_MX;
break;
case 1: /* /proc/curproc */
vap->va_nlink = 1;
vap->va_uid = 0;
vap->va_gid = 0;
break;
default:
panic("procfs_getattr root");
}
break;
case Pproc:
vap->va_nlink = 2;
vap->va_bytes = vap->va_size = Nprocent * UIO_MX;
break;
case Pmem:
vap->va_bytes = vap->va_size =
ctob(procp->p_vmspace->vm_tsize +
procp->p_vmspace->vm_dsize +
procp->p_vmspace->vm_ssize);
break;
case Pregs:
#if defined(PT_GETREGS) || defined(PT_SETREGS)
vap->va_bytes = vap->va_size = sizeof(struct reg);
#else
vap->va_bytes = vap->va_size = 0;
#endif
break;
case Pfpregs:
#if defined(PT_GETFPREGS) || defined(PT_SETFPREGS)
vap->va_bytes = vap->va_size = sizeof(struct fpreg);
#else
vap->va_bytes = vap->va_size = 0;
#endif
break;
case Pstatus:
vap->va_bytes = vap->va_size = 256; /* only a maximum */
break;
case Pctl:
vap->va_bytes = vap->va_size = PROCFS_CTLLEN;
break;
case Pnote:
vap->va_bytes = vap->va_size = PROCFS_NOTELEN;
break;
case Pnotepg:
break;
default:
panic("procfs_getattr type");
}
return (error);
}
procfs_setattr(vp, vap, cred, p)
struct vnode *vp;
struct vattr *vap;
struct ucred *cred;
struct proc *p;
{
/*
* just fake out attribute setting
* it's not good to generate an error
* return, otherwise things like creat()
* will fail when they try to set the
* file length to 0. worse, this means
* that echo $note > /proc/$pid/note will fail.
*/
return (0);
}
/*
* implement access checking.
*
* something very similar to this code is duplicated
* throughout the 4bsd kernel and should be moved
* into kern/vfs_subr.c sometime.
*
* actually, the check for super-user is slightly
* broken since it will allow read access to write-only
* objects. this doesn't cause any particular trouble
* but does mean that the i/o entry points need to check
* that the operation really does make sense.
*/
procfs_access(vp, mode, cred, p)
struct vnode *vp;
int mode;
struct ucred *cred;
struct proc *p;
{
struct vattr *vap;
struct vattr vattr;
int error;
/*
* If you're the super-user,
* you always get access.
*/
if (cred->cr_uid == (uid_t) 0)
return (0);
vap = &vattr;
if (error = VOP_GETATTR(vp, vap, cred, p))
return (error);
/*
* Access check is based on only one of owner, group, public.
* If not owner, then check group. If not a member of the
* group, then check public access.
*/
if (cred->cr_uid != vap->va_uid) {
gid_t *gp;
int i;
mode >>= 3;
gp = cred->cr_groups;
for (i = 0; i < cred->cr_ngroups; i++, gp++)
if (vap->va_gid == *gp)
goto found;
mode >>= 3;
found:
;
}
if ((vap->va_mode & mode) == mode)
return (0);
return (EACCES);
}
/*
* lookup. this is incredibly complicated in the
* general case, however for most pseudo-filesystems
* very little needs to be done.
*
* (dvp) is the directory in which the lookup takes place.
* (ndp) contains all the information about the type of
* lookup being done.
*
* (dvp) is locked on entry.
* the job of lookup is to set ndp->ni_dvp, and ndp->ni_vp.
* (this changes in 4.4 where all we want is the equivalent
* of ndp->ni_vp.)
*
* unless you want to get a migraine, just make sure your
* filesystem doesn't do any locking of its own. otherwise
* read and inwardly digest ufs_lookup().
*/
procfs_lookup(dvp, ndp, p)
struct vnode *dvp;
struct nameidata *ndp;
struct proc *p;
{
char *pname = ndp->ni_ptr;
int error = 0;
int flag;
pid_t pid;
struct vnode *nvp;
struct pfsnode *pfs;
struct proc *procp;
int mode;
pfstype pfs_type;
int i;
if (ndp->ni_namelen == 1 && *pname == '.') {
ndp->ni_vp = dvp;
ndp->ni_dvp = dvp;
VREF(dvp);
return (0);
}
ndp->ni_dvp = dvp;
ndp->ni_vp = NULL;
pfs = VTOPFS(dvp);
switch (pfs->pfs_type) {
case Proot:
if (ndp->ni_isdotdot)
return (EIO);
if (NDEQ(ndp, "curproc", 7)) {
if (error = procfs_allocvp(dvp->v_mount, &nvp, 1, Proot))
return error;
ndp->ni_vp = nvp;
return 0;
}
pid = atopid(pname, ndp->ni_namelen);
if (pid == NO_PID)
return (ENOENT);
procp = PFIND(pid);
if (procp == 0)
return (ENOENT);
error = procfs_allocvp(dvp->v_mount, &nvp, pid, Pproc);
if (error)
return (error);
ndp->ni_vp = nvp;
return (0);
case Pproc:
if (ndp->ni_isdotdot) {
ndp->ni_dvp = dvp;
error = procfs_root(dvp->v_mount, &ndp->ni_vp);
return (error);
}
procp = PFIND(pfs->pfs_pid);
if (procp == 0)
return (ENOENT);
for (i = 0; i < Nprocent; i++) {
struct pfsnames *dp = &procent[i];
if (ndp->ni_namelen == dp->d_namlen &&
bcmp(pname, dp->d_name, dp->d_namlen) == 0) {
pfs_type = dp->d_pfstype;
goto found;
}
}
return (ENOENT);
found:
if (pfs_type == Pfile) {
nvp = procfs_findtextvp(procp);
if (nvp) {
VREF(nvp);
VOP_LOCK(nvp);
} else {
error = ENXIO;
}
} else {
error = procfs_allocvp(dvp->v_mount, &nvp,
pfs->pfs_pid, pfs_type);
if (error)
return (error);
pfs = VTOPFS(nvp);
}
ndp->ni_vp = nvp;
return (error);
default:
return (ENOTDIR);
}
}
/*
* readdir returns directory entries from pfsnode (vp).
*
* the strategy here with procfs is to generate a single
* directory entry at a time (struct pfsdent) and then
* copy that out to userland using uiomove. a more efficent
* though more complex implementation, would try to minimize
* the number of calls to uiomove(). for procfs, this is
* hardly worth the added code complexity.
*
* this should just be done through read()
*/
procfs_readdir(vp, uio, cred, eofflagp, cookies, ncookies)
struct vnode *vp;
struct uio *uio;
struct ucred *cred;
int *eofflagp;
u_int *cookies;
int ncookies;
{
struct pfsdent d;
struct pfsdent *dp = &d;
struct pfsnode *pfs;
int error;
int count;
int i;
/*
* NFS mounting of procfs doesn't work correctly.
* The files in procfs are more similar to devices
* than to regular files.
* See also procfs_vptofh & procfs_fhtovp in procfs_vfsops.c
*/
if (cookies)
panic("procfs_readdir");
pfs = VTOPFS(vp);
if (uio->uio_resid < UIO_MX)
return (EINVAL);
if (uio->uio_offset & (UIO_MX-1))
return (EINVAL);
if (uio->uio_offset < 0)
return (EINVAL);
error = 0;
count = 0;
i = uio->uio_offset / UIO_MX;
switch (pfs->pfs_type) {
/*
* this is for the process-specific sub-directories.
* all that is needed to is copy out all the entries
* from the procent[] table (top of this file).
*/
case Pproc: {
while (uio->uio_resid >= UIO_MX && (!cookies || ncookies > 0)) {
struct pfsnames *dt;
pid_t pid = pfs->pfs_pid;
if (i >= Nprocent) {
*eofflagp = 1;
break;
}
dt = &procent[i];
dp->d_reclen = UIO_MX;
if (dt->d_pfstype == Proot)
pid = 0;
dp->d_fileno = PROCFS_FILENO(pid, dt->d_pfstype);
dp->d_namlen = dt->d_namlen;
bcopy(dt->d_name, dp->d_name, sizeof(dt->d_name)-1);
error = uiomove((caddr_t) dp, UIO_MX, uio);
if (error)
break;
count += UIO_MX;
i++;
if (cookies) {
*cookies++ = i * UIO_MX;
ncookies--;
}
}
break;
}
/*
* this is for the root of the procfs filesystem
* what is needed is a special entry for "curproc"
* followed by an entry for each process on allproc
#ifdef PROCFS_ZOMBIE
* and zombproc.
#endif
*/
case Proot: {
int pcnt;
#ifdef PROCFS_ZOMBIE
int doingzomb = 0;
#endif
struct proc *p;
p = (struct proc *) allproc;
pcnt = PROCFS_XFILES;
while (p && uio->uio_resid >= UIO_MX && (!cookies || ncookies > 0)) {
bzero((char *) dp, UIO_MX);
dp->d_reclen = UIO_MX;
switch (i) {
case 0: /* `.' */
case 1: /* `..' */
dp->d_fileno = PROCFS_FILENO(0, Proot);
bcopy("..",dp->d_name,3);
dp->d_namlen = i + 1;
dp->d_name[i + 1] = 0;
break;
case 2:
/* ship out entry for "curproc" */
dp->d_fileno = PROCFS_FILENO(1, Proot);
dp->d_namlen = 7;
bcopy("curproc", dp->d_name, dp->d_namlen+1);
break;
default:
if (pcnt >= i) {
dp->d_fileno = PROCFS_FILENO(p->p_pid, Pproc);
dp->d_namlen = sprintf(dp->d_name, "%ld", (long) p->p_pid);
}
p = p->p_nxt;
#ifdef PROCFS_ZOMBIE
if (p == 0 && doingzomb == 0) {
doingzomb = 1;
p = zombproc;
}
#endif
if (pcnt++ < i)
continue;
break;
}
error = uiomove((caddr_t) dp, UIO_MX, uio);
if (error)
break;
count += UIO_MX;
i++;
if (cookies) {
*cookies++ = i * UIO_MX;
ncookies--;
}
}
break;
}
default:
error = ENOTDIR;
break;
}
uio->uio_offset = i * UIO_MX;
if (count == 0)
*eofflagp = 1;
return (error);
}
/*
* readlink reads the link of "curproc"
*/
procfs_readlink(vp, uio, cred)
struct vnode *vp;
struct uio *uio;
struct ucred *cred;
{
struct pfsnode *pfs = VTOPFS(vp);
char buf[16]; /* should be enough */
int len;
if (pfs->pfs_fileno != PROCFS_FILENO(1,Proot))
return EINVAL;
len = sprintf(buf,"%ld",(long)curproc->p_pid);
return uiomove(buf, len, uio);
}
/*
* convert decimal ascii to pid_t
*/
static pid_t
atopid(b, len)
const char *b;
u_int len;
{
pid_t p = 0;
while (len--) {
char c = *b++;
if (c < '0' || c > '9')
return (NO_PID);
p = 10 * p + (c - '0');
if (p > PID_MAX)
return (NO_PID);
}
return (p);
}
/*
* procfs vnode operations.
*/
struct vnodeops procfs_vnodeops = {
procfs_lookup, /* lookup */
procfs_create, /* create */
procfs_mknod, /* mknod */
procfs_open, /* open */
procfs_close, /* close */
procfs_access, /* access */
procfs_getattr, /* getattr */
procfs_setattr, /* setattr */
procfs_read, /* read */
procfs_write, /* write */
procfs_ioctl, /* ioctl */
procfs_select, /* select */
procfs_mmap, /* mmap */
procfs_fsync, /* fsync */
procfs_seek, /* seek */
procfs_remove, /* remove */
procfs_link, /* link */
procfs_rename, /* rename */
procfs_mkdir, /* mkdir */
procfs_rmdir, /* rmdir */
procfs_symlink, /* symlink */
procfs_readdir, /* readdir */
procfs_readlink, /* readlink */
procfs_abortop, /* abortop */
procfs_inactive, /* inactive */
procfs_reclaim, /* reclaim */
procfs_lock, /* lock */
procfs_unlock, /* unlock */
procfs_bmap, /* bmap */
procfs_strategy, /* strategy */
procfs_print, /* print */
procfs_islocked, /* islocked */
procfs_advlock, /* advlock */
};