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 1.5 2003/08/07 21:17:43 dillon 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>
53 static struct pfsnode *pfshead;
57 * allocate a pfsnode/vnode pair. the vnode is
58 * referenced, but not locked.
60 * the pid, pfs_type, and mount point uniquely
61 * identify a pfsnode. the mount point is needed
62 * because someone might mount this filesystem
65 * all pfsnodes are maintained on a singly-linked
66 * list. new nodes are only allocated when they cannot
67 * be found on this list. entries on the list are
68 * removed when the vfs reclaim entry is called.
70 * a single lock is kept for the entire list. this is
71 * needed because the getnewvnode() function can block
72 * waiting for a vnode to become free, in which case there
73 * may be more than one process trying to get the same
74 * vnode. this lock is only taken if we are going to
75 * call getnewvnode, since the kernel itself is single-threaded.
77 * if an entry is found on the list, then call vget() to
78 * take a reference. this is done because there may be
79 * zero references to it and so it needs to removed from
80 * the vnode free list.
83 procfs_allocvp(mp, vpp, pid, pfs_type)
89 struct thread *td = curthread; /* XXX */
96 for (pfs = pfshead; pfs != 0; pfs = pfs->pfs_next) {
98 if (pfs->pfs_pid == pid &&
99 pfs->pfs_type == pfs_type &&
109 * otherwise lock the vp list while we call getnewvnode
110 * since that can block.
112 if (pfsvplock & PROCFS_LOCKED) {
113 pfsvplock |= PROCFS_WANT;
114 (void) tsleep((caddr_t) &pfsvplock, 0, "pfsavp", 0);
117 pfsvplock |= PROCFS_LOCKED;
120 * Do the MALLOC before the getnewvnode since doing so afterward
121 * might cause a bogus v_data pointer to get dereferenced
122 * elsewhere if MALLOC should block.
124 MALLOC(pfs, struct pfsnode *, sizeof(struct pfsnode), M_TEMP, M_WAITOK);
126 if ((error = getnewvnode(VT_PROCFS, mp, procfs_vnodeop_p, vpp)) != 0) {
135 pfs->pfs_pid = (pid_t) pid;
136 pfs->pfs_type = pfs_type;
139 pfs->pfs_lockowner = 0;
140 pfs->pfs_fileno = PROCFS_FILENO(pid, pfs_type);
143 case Proot: /* /proc = dr-xr-xr-x */
144 pfs->pfs_mode = (VREAD|VEXEC) |
151 case Pcurproc: /* /proc/curproc = lr--r--r-- */
152 pfs->pfs_mode = (VREAD) |
159 pfs->pfs_mode = (VREAD|VEXEC) |
166 pfs->pfs_mode = (VREAD|VEXEC) |
173 pfs->pfs_mode = (VREAD|VWRITE);
180 pfs->pfs_mode = (VREAD|VWRITE);
187 pfs->pfs_mode = (VWRITE);
196 pfs->pfs_mode = (VREAD) |
203 panic("procfs_allocvp");
206 /* add to procfs vnode list */
207 for (pp = &pfshead; *pp; pp = &(*pp)->pfs_next)
212 pfsvplock &= ~PROCFS_LOCKED;
214 if (pfsvplock & PROCFS_WANT) {
215 pfsvplock &= ~PROCFS_WANT;
216 wakeup((caddr_t) &pfsvplock);
226 struct pfsnode **pfspp;
227 struct pfsnode *pfs = VTOPFS(vp);
229 for (pfspp = &pfshead; *pfspp != 0; pfspp = &(*pfspp)->pfs_next) {
231 *pfspp = pfs->pfs_next;
236 FREE(vp->v_data, M_TEMP);
242 procfs_rw(struct vop_read_args *ap)
244 struct vnode *vp = ap->a_vp;
245 struct uio *uio = ap->a_uio;
246 struct thread *curtd = uio->uio_td;
248 struct pfsnode *pfs = VTOPFS(vp);
254 if ((curp = curtd->td_proc) == NULL) /* XXX */
257 p = PFIND(pfs->pfs_pid);
260 if (p->p_pid == 1 && securelevel > 0 && uio->uio_rw == UIO_WRITE)
263 while (pfs->pfs_lockowner) {
264 tsleep(&pfs->pfs_lockowner, 0, "pfslck", 0);
266 pfs->pfs_lockowner = curproc->p_pid;
268 switch (pfs->pfs_type) {
271 rtval = procfs_donote(curp, p, pfs, uio);
275 rtval = procfs_doregs(curp, p, pfs, uio);
279 rtval = procfs_dofpregs(curp, p, pfs, uio);
283 rtval = procfs_dodbregs(curp, p, pfs, uio);
287 rtval = procfs_doctl(curp, p, pfs, uio);
291 rtval = procfs_dostatus(curp, p, pfs, uio);
295 rtval = procfs_domap(curp, p, pfs, uio);
299 rtval = procfs_domem(curp, p, pfs, uio);
303 rtval = procfs_dotype(curp, p, pfs, uio);
307 rtval = procfs_docmdline(curp, p, pfs, uio);
311 rtval = procfs_dorlimit(curp, p, pfs, uio);
318 pfs->pfs_lockowner = 0;
319 wakeup(&pfs->pfs_lockowner);
324 * Get a string from userland into (buf). Strip a trailing
325 * nl character (to allow easy access from the shell).
326 * The buffer should be *buflenp + 1 chars long. vfs_getuserstr
327 * will automatically add a nul char at the end.
329 * Returns 0 on success or the following errors
331 * EINVAL: file offset is non-zero.
332 * EMSGSIZE: message is longer than kernel buffer
333 * EFAULT: user i/o buffer is not addressable
336 vfs_getuserstr(uio, buf, buflenp)
344 if (uio->uio_offset != 0)
349 /* must be able to read the whole string in one go */
350 if (xlen < uio->uio_resid)
352 xlen = uio->uio_resid;
354 if ((error = uiomove(buf, xlen, uio)) != 0)
357 /* allow multiple writes without seeks */
360 /* cleanup string and remove trailing newline */
363 if (xlen > 0 && buf[xlen-1] == '\n')
371 vfs_findname(nm, buf, buflen)
377 for (; nm->nm_name; nm++)
378 if (bcmp(buf, nm->nm_name, buflen+1) == 0)
385 procfs_exit(struct thread *td)
390 KKASSERT(td->td_proc);
391 pid = td->td_proc->p_pid;
394 * The reason for this loop is not obvious -- basicly,
395 * procfs_freevp(), which is called via vgone() (eventually),
396 * removes the specified procfs node from the pfshead list.
397 * It does this by *pfsp = pfs->pfs_next, meaning that it
398 * overwrites the node. So when we do pfs = pfs->next, we
399 * end up skipping the node that replaces the one that was
400 * vgone'd. Since it may have been the last one on the list,
401 * it may also have been set to null -- but *our* pfs pointer,
402 * here, doesn't see this. So the loop starts from the beginning
405 * This is not a for() loop because the final event
406 * would be "pfs = pfs->pfs_next"; in the case where
407 * pfs is set to pfshead again, that would mean that
408 * pfshead is skipped over.
413 if (pfs->pfs_pid == pid) {