2 * Copyright (c) 1993 Jan-Simon Pendry
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
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37 * @(#)procfs_subr.c 8.6 (Berkeley) 5/14/95
39 * $FreeBSD: src/sys/miscfs/procfs/procfs_subr.c,v 1.26.2.3 2002/02/18 21:28:04 des Exp $
40 * $DragonFly: src/sys/vfs/procfs/procfs_subr.c,v 1.18 2007/08/25 23:27:02 corecode Exp $
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/sysctl.h>
47 #include <sys/mount.h>
48 #include <sys/vnode.h>
49 #include <sys/malloc.h>
51 #include <vfs/procfs/procfs.h>
54 #define PFS_HMASK (PFS_HSIZE - 1)
56 static struct pfsnode *pfshead[PFS_HSIZE];
59 #define PFSHASH(pid) &pfshead[(pid) & PFS_HMASK]
62 * Allocate a pfsnode/vnode pair. If no error occurs the returned vnode
63 * will be referenced and exclusively locked.
65 * The pid, pfs_type, and mount point uniquely identify a pfsnode.
66 * The mount point is needed because someone might mount this filesystem
69 * All pfsnodes are maintained on a singly-linked list. new nodes are
70 * only allocated when they cannot be found on this list. entries on
71 * the list are removed when the vfs reclaim entry is called.
73 * A single lock is kept for the entire list. this is needed because the
74 * getnewvnode() function can block waiting for a vnode to become free,
75 * in which case there may be more than one process trying to get the same
76 * vnode. this lock is only taken if we are going to call getnewvnode,
77 * since the kernel itself is single-threaded.
79 * If an entry is found on the list, then call vget() to take a reference
80 * and obtain the lock. This will properly re-reference the vnode if it
81 * had gotten onto the free list.
84 procfs_allocvp(struct mount *mp, struct vnode **vpp, long pid, pfstype pfs_type)
93 for (pfs = *pp; pfs; pfs = pfs->pfs_next) {
94 if (pfs->pfs_pid == pid && pfs->pfs_type == pfs_type &&
95 PFSTOV(pfs)->v_mount == mp) {
97 if (vget(vp, LK_EXCLUSIVE))
101 * Make sure the vnode is still in the cache after
102 * getting the interlock to avoid racing a free.
104 for (pfs = *pp; pfs; pfs = pfs->pfs_next) {
105 if (PFSTOV(pfs) == vp &&
106 pfs->pfs_pid == pid &&
107 pfs->pfs_type == pfs_type &&
108 PFSTOV(pfs)->v_mount == mp) {
112 if (pfs == NULL || PFSTOV(pfs) != vp) {
123 * otherwise lock the vp list while we call getnewvnode
124 * since that can block.
126 if (pfsvplock & PROCFS_LOCKED) {
127 pfsvplock |= PROCFS_WANT;
128 (void) tsleep((caddr_t) &pfsvplock, 0, "pfsavp", 0);
131 pfsvplock |= PROCFS_LOCKED;
134 * Do the MALLOC before the getnewvnode since doing so afterward
135 * might cause a bogus v_data pointer to get dereferenced
136 * elsewhere if MALLOC should block.
138 * XXX this may not matter anymore since getnewvnode now returns
141 MALLOC(pfs, struct pfsnode *, sizeof(struct pfsnode), M_TEMP, M_WAITOK);
143 error = getnewvnode(VT_PROCFS, mp, vpp, 0, 0);
153 pfs->pfs_pid = (pid_t) pid;
154 pfs->pfs_type = pfs_type;
157 pfs->pfs_lockowner = 0;
158 pfs->pfs_fileno = PROCFS_FILENO(pid, pfs_type);
161 case Proot: /* /proc = dr-xr-xr-x */
162 pfs->pfs_mode = (VREAD|VEXEC) |
169 case Pcurproc: /* /proc/curproc = lr--r--r-- */
170 pfs->pfs_mode = (VREAD) |
177 pfs->pfs_mode = (VREAD|VEXEC) |
184 pfs->pfs_mode = (VREAD|VEXEC) |
191 pfs->pfs_mode = (VREAD|VWRITE);
198 pfs->pfs_mode = (VREAD|VWRITE);
205 pfs->pfs_mode = (VWRITE);
214 pfs->pfs_mode = (VREAD) |
221 panic("procfs_allocvp");
224 /* add to procfs vnode list */
229 pfsvplock &= ~PROCFS_LOCKED;
231 if (pfsvplock & PROCFS_WANT) {
232 pfsvplock &= ~PROCFS_WANT;
233 wakeup((caddr_t) &pfsvplock);
240 procfs_freevp(struct vnode *vp)
242 struct pfsnode **pfspp;
248 pfspp = PFSHASH(pfs->pfs_pid);
249 while (*pfspp != pfs && *pfspp)
250 pfspp = &(*pfspp)->pfs_next;
252 *pfspp = pfs->pfs_next;
253 pfs->pfs_next = NULL;
259 procfs_rw(struct vop_read_args *ap)
261 struct vnode *vp = ap->a_vp;
262 struct uio *uio = ap->a_uio;
263 struct thread *curtd = uio->uio_td;
265 struct pfsnode *pfs = VTOPFS(vp);
272 if ((curp = curtd->td_proc) == NULL) /* XXX */
275 p = PFIND(pfs->pfs_pid);
278 if (p->p_pid == 1 && securelevel > 0 && uio->uio_rw == UIO_WRITE)
281 lp = FIRST_LWP_IN_PROC(p);
284 while (pfs->pfs_lockowner) {
285 tsleep(&pfs->pfs_lockowner, 0, "pfslck", 0);
287 pfs->pfs_lockowner = curproc->p_pid;
289 switch (pfs->pfs_type) {
292 rtval = procfs_donote(curp, lp, pfs, uio);
296 rtval = procfs_doregs(curp, lp, pfs, uio);
300 rtval = procfs_dofpregs(curp, lp, pfs, uio);
304 rtval = procfs_dodbregs(curp, lp, pfs, uio);
308 rtval = procfs_doctl(curp, lp, pfs, uio);
312 rtval = procfs_dostatus(curp, lp, pfs, uio);
316 rtval = procfs_domap(curp, lp, pfs, uio);
320 rtval = procfs_domem(curp, lp, pfs, uio);
324 rtval = procfs_dotype(curp, lp, pfs, uio);
328 rtval = procfs_docmdline(curp, lp, pfs, uio);
332 rtval = procfs_dorlimit(curp, lp, pfs, uio);
340 pfs->pfs_lockowner = 0;
341 wakeup(&pfs->pfs_lockowner);
346 * Get a string from userland into (buf). Strip a trailing
347 * nl character (to allow easy access from the shell).
348 * The buffer should be *buflenp + 1 chars long. vfs_getuserstr
349 * will automatically add a nul char at the end.
351 * Returns 0 on success or the following errors
353 * EINVAL: file offset is non-zero.
354 * EMSGSIZE: message is longer than kernel buffer
355 * EFAULT: user i/o buffer is not addressable
358 vfs_getuserstr(struct uio *uio, char *buf, int *buflenp)
363 if (uio->uio_offset != 0)
368 /* must be able to read the whole string in one go */
369 if (xlen < uio->uio_resid)
371 xlen = uio->uio_resid;
373 if ((error = uiomove(buf, xlen, uio)) != 0)
376 /* allow multiple writes without seeks */
379 /* cleanup string and remove trailing newline */
382 if (xlen > 0 && buf[xlen-1] == '\n')
390 vfs_findname(vfs_namemap_t *nm, char *buf, int buflen)
393 for (; nm->nm_name; nm++)
394 if (bcmp(buf, nm->nm_name, buflen+1) == 0)
401 procfs_exit(struct thread *td)
407 KKASSERT(td->td_proc);
408 pid = td->td_proc->p_pid;
411 * The reason for this loop is not obvious -- basicly,
412 * procfs_freevp(), which is called via vgone() (eventually),
413 * removes the specified procfs node from the pfshead list.
414 * It does this by *pfsp = pfs->pfs_next, meaning that it
415 * overwrites the node. So when we do pfs = pfs->next, we
416 * end up skipping the node that replaces the one that was
417 * vgone'd. Since it may have been the last one on the list,
418 * it may also have been set to null -- but *our* pfs pointer,
419 * here, doesn't see this. So the loop starts from the beginning
422 * This is not a for() loop because the final event
423 * would be "pfs = pfs->pfs_next"; in the case where
424 * pfs is set to pfshead again, that would mean that
425 * pfshead is skipped over.
431 if (pfs->pfs_pid == pid) {