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procfs_vfsops.c revision 1.117
      1 /*	$NetBSD: procfs_vfsops.c,v 1.117 2024/07/01 01:35:53 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Jan-Simon Pendry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  *	@(#)procfs_vfsops.c	8.7 (Berkeley) 5/10/95
     35  */
     36 
     37 /*
     38  * Copyright (c) 1993 Jan-Simon Pendry
     39  *
     40  * This code is derived from software contributed to Berkeley by
     41  * Jan-Simon Pendry.
     42  *
     43  * Redistribution and use in source and binary forms, with or without
     44  * modification, are permitted provided that the following conditions
     45  * are met:
     46  * 1. Redistributions of source code must retain the above copyright
     47  *    notice, this list of conditions and the following disclaimer.
     48  * 2. Redistributions in binary form must reproduce the above copyright
     49  *    notice, this list of conditions and the following disclaimer in the
     50  *    documentation and/or other materials provided with the distribution.
     51  * 3. All advertising materials mentioning features or use of this software
     52  *    must display the following acknowledgement:
     53  *	This product includes software developed by the University of
     54  *	California, Berkeley and its contributors.
     55  * 4. Neither the name of the University nor the names of its contributors
     56  *    may be used to endorse or promote products derived from this software
     57  *    without specific prior written permission.
     58  *
     59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     69  * SUCH DAMAGE.
     70  *
     71  *	@(#)procfs_vfsops.c	8.7 (Berkeley) 5/10/95
     72  */
     73 
     74 /*
     75  * procfs VFS interface
     76  */
     77 
     78 #include <sys/cdefs.h>
     79 __KERNEL_RCSID(0, "$NetBSD: procfs_vfsops.c,v 1.117 2024/07/01 01:35:53 christos Exp $");
     80 
     81 #if defined(_KERNEL_OPT)
     82 #include "opt_compat_netbsd.h"
     83 #endif
     84 
     85 #include <sys/param.h>
     86 #include <sys/atomic.h>
     87 #include <sys/buf.h>
     88 #include <sys/dirent.h>
     89 #include <sys/file.h>
     90 #include <sys/filedesc.h>
     91 #include <sys/fstrans.h>
     92 #include <sys/kauth.h>
     93 #include <sys/kernel.h>
     94 #include <sys/module.h>
     95 #include <sys/mount.h>
     96 #include <sys/proc.h>
     97 #include <sys/signalvar.h>
     98 #include <sys/sysctl.h>
     99 #include <sys/syslog.h>
    100 #include <sys/systm.h>
    101 #include <sys/time.h>
    102 #include <sys/vnode.h>
    103 
    104 #include <miscfs/genfs/genfs.h>
    105 
    106 #include <miscfs/procfs/procfs.h>
    107 
    108 #include <uvm/uvm_extern.h>			/* for PAGE_SIZE */
    109 
    110 MODULE(MODULE_CLASS_VFS, procfs, "ptrace_common");
    111 
    112 VFS_PROTOS(procfs);
    113 
    114 #define PROCFS_HASHSIZE	256
    115 #define PROCFS_EXEC_HOOK ((void *)1)
    116 #define PROCFS_EXIT_HOOK ((void *)2)
    117 
    118 static kauth_listener_t procfs_listener;
    119 static void *procfs_exechook;
    120 static void *procfs_exithook;
    121 LIST_HEAD(hashhead, pfsnode);
    122 static u_long procfs_hashmask;
    123 static struct hashhead *procfs_hashtab;
    124 static kmutex_t procfs_hashlock;
    125 
    126 static struct hashhead *
    127 procfs_hashhead(pid_t pid)
    128 {
    129 
    130 	return &procfs_hashtab[pid & procfs_hashmask];
    131 }
    132 
    133 void
    134 procfs_hashrem(struct pfsnode *pfs)
    135 {
    136 
    137 	mutex_enter(&procfs_hashlock);
    138 	LIST_REMOVE(pfs, pfs_hash);
    139 	mutex_exit(&procfs_hashlock);
    140 }
    141 
    142 /*
    143  * VFS Operations.
    144  *
    145  * mount system call
    146  */
    147 /* ARGSUSED */
    148 int
    149 procfs_mount(
    150     struct mount *mp,
    151     const char *path,
    152     void *data,
    153     size_t *data_len)
    154 {
    155 	struct lwp *l = curlwp;
    156 	struct procfsmount *pmnt;
    157 	struct procfs_args *args = data;
    158 	int error;
    159 
    160 	if (args == NULL)
    161 		return EINVAL;
    162 
    163 	if (UIO_MX & (UIO_MX-1)) {
    164 		log(LOG_ERR, "procfs: invalid directory entry size");
    165 		return (EINVAL);
    166 	}
    167 
    168 	if (mp->mnt_flag & MNT_GETARGS) {
    169 		if (*data_len < sizeof *args)
    170 			return EINVAL;
    171 
    172 		pmnt = VFSTOPROC(mp);
    173 		if (pmnt == NULL)
    174 			return EIO;
    175 		args->version = PROCFS_ARGSVERSION;
    176 		args->flags = pmnt->pmnt_flags;
    177 		*data_len = sizeof *args;
    178 		return 0;
    179 	}
    180 
    181 	if (mp->mnt_flag & MNT_UPDATE)
    182 		return (EOPNOTSUPP);
    183 
    184 	if (*data_len >= sizeof *args && args->version != PROCFS_ARGSVERSION)
    185 		return EINVAL;
    186 
    187 	pmnt = kmem_zalloc(sizeof(struct procfsmount), KM_SLEEP);
    188 
    189 	mp->mnt_stat.f_namemax = PROCFS_MAXNAMLEN;
    190 	mp->mnt_flag |= MNT_LOCAL;
    191 	mp->mnt_data = pmnt;
    192 	vfs_getnewfsid(mp);
    193 
    194 	error = set_statvfs_info(path, UIO_USERSPACE, "procfs", UIO_SYSSPACE,
    195 	    mp->mnt_op->vfs_name, mp, l);
    196 	if (*data_len >= sizeof *args)
    197 		pmnt->pmnt_flags = args->flags;
    198 	else
    199 		pmnt->pmnt_flags = 0;
    200 
    201 	mp->mnt_iflag |= IMNT_MPSAFE | IMNT_SHRLOOKUP;
    202 	return error;
    203 }
    204 
    205 /*
    206  * unmount system call
    207  */
    208 int
    209 procfs_unmount(struct mount *mp, int mntflags)
    210 {
    211 	int error;
    212 	int flags = 0;
    213 
    214 	if (mntflags & MNT_FORCE)
    215 		flags |= FORCECLOSE;
    216 
    217 	if ((error = vflush(mp, 0, flags)) != 0)
    218 		return (error);
    219 
    220 	kmem_free(mp->mnt_data, sizeof(struct procfsmount));
    221 	mp->mnt_data = NULL;
    222 
    223 	return 0;
    224 }
    225 
    226 int
    227 procfs_root(struct mount *mp, int lktype, struct vnode **vpp)
    228 {
    229 	int error;
    230 
    231 	error = procfs_allocvp(mp, vpp, 0, PFSroot, -1);
    232 	if (error == 0) {
    233 		error = vn_lock(*vpp, lktype);
    234 		if (error != 0) {
    235 			vrele(*vpp);
    236 			*vpp = NULL;
    237 		}
    238 	}
    239 
    240 	return error;
    241 }
    242 
    243 /* ARGSUSED */
    244 int
    245 procfs_start(struct mount *mp, int flags)
    246 {
    247 
    248 	return (0);
    249 }
    250 
    251 /*
    252  * Get file system statistics.
    253  */
    254 int
    255 procfs_statvfs(struct mount *mp, struct statvfs *sbp)
    256 {
    257 
    258 	genfs_statvfs(mp, sbp);
    259 
    260 	sbp->f_bsize = PAGE_SIZE;
    261 	sbp->f_frsize = PAGE_SIZE;
    262 	sbp->f_iosize = PAGE_SIZE;
    263 	sbp->f_blocks = 1;
    264 	sbp->f_files = maxproc;					/* approx */
    265 	sbp->f_ffree = maxproc - atomic_load_relaxed(&nprocs);	/* approx */
    266 	sbp->f_favail = maxproc - atomic_load_relaxed(&nprocs);	/* approx */
    267 
    268 	return (0);
    269 }
    270 
    271 /*ARGSUSED*/
    272 int
    273 procfs_sync(
    274     struct mount *mp,
    275     int waitfor,
    276     kauth_cred_t uc)
    277 {
    278 
    279 	return (0);
    280 }
    281 
    282 /*ARGSUSED*/
    283 int
    284 procfs_vget(struct mount *mp, ino_t ino, int lktype,
    285     struct vnode **vpp)
    286 {
    287 	return (EOPNOTSUPP);
    288 }
    289 
    290 int
    291 procfs_loadvnode(struct mount *mp, struct vnode *vp,
    292     const void *key, size_t key_len, const void **new_key)
    293 {
    294 	int error;
    295 	struct pfskey pfskey;
    296 	struct pfsnode *pfs;
    297 
    298 	KASSERT(key_len == sizeof(pfskey));
    299 	memcpy(&pfskey, key, key_len);
    300 
    301 	pfs = kmem_alloc(sizeof(*pfs), KM_SLEEP);
    302 	pfs->pfs_pid = pfskey.pk_pid;
    303 	pfs->pfs_type = pfskey.pk_type;
    304 	pfs->pfs_fd = pfskey.pk_fd;
    305 	pfs->pfs_vnode = vp;
    306 	pfs->pfs_mount = mp;
    307 	pfs->pfs_flags = 0;
    308 	pfs->pfs_fileno =
    309 	    PROCFS_FILENO(pfs->pfs_pid, pfs->pfs_type, pfs->pfs_fd);
    310 	vp->v_tag = VT_PROCFS;
    311 	vp->v_op = procfs_vnodeop_p;
    312 	vp->v_data = pfs;
    313 
    314 	switch (pfs->pfs_type) {
    315 	case PFSroot:	/* /proc = dr-xr-xr-x */
    316 		vp->v_vflag |= VV_ROOT;
    317 		/*FALLTHROUGH*/
    318 	case PFSproc:	/* /proc/N = dr-xr-xr-x */
    319 		pfs->pfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
    320 		vp->v_type = VDIR;
    321 		break;
    322 
    323 	case PFStask:	/* /proc/N/task = dr-xr-xr-x */
    324 		if (pfs->pfs_fd == -1) {
    325 			pfs->pfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|
    326 			    S_IROTH|S_IXOTH;
    327 			vp->v_type = VDIR;
    328 			break;
    329 		}
    330 		/*FALLTHROUGH*/
    331 	case PFScurproc:	/* /proc/curproc = lr-xr-xr-x */
    332 	case PFSself:	/* /proc/self    = lr-xr-xr-x */
    333 	case PFScwd:	/* /proc/N/cwd = lr-xr-xr-x */
    334 	case PFSchroot:	/* /proc/N/chroot = lr-xr-xr-x */
    335 	case PFSexe:	/* /proc/N/exe = lr-xr-xr-x */
    336 		pfs->pfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
    337 		vp->v_type = VLNK;
    338 		break;
    339 
    340 	case PFSfd:
    341 		if (pfs->pfs_fd == -1) {	/* /proc/N/fd = dr-x------ */
    342 			pfs->pfs_mode = S_IRUSR|S_IXUSR;
    343 			vp->v_type = VDIR;
    344 		} else {	/* /proc/N/fd/M = [ps-]rw------- */
    345 			file_t *fp;
    346 			vnode_t *vxp;
    347 			struct proc *p;
    348 
    349 			mutex_enter(&proc_lock);
    350 			p = procfs_proc_find(mp, pfs->pfs_pid);
    351 			mutex_exit(&proc_lock);
    352 			if (p == NULL) {
    353 				error = ENOENT;
    354 				goto bad;
    355 			}
    356 			KASSERT(rw_read_held(&p->p_reflock));
    357 			if ((fp = fd_getfile2(p, pfs->pfs_fd)) == NULL) {
    358 				error = EBADF;
    359 				goto bad;
    360 			}
    361 
    362 			pfs->pfs_mode = S_IRUSR|S_IWUSR;
    363 			switch (fp->f_type) {
    364 			case DTYPE_VNODE:
    365 				vxp = fp->f_vnode;
    366 
    367 				/*
    368 				 * We make symlinks for directories
    369 				 * to avoid cycles.
    370 				 */
    371 				if (vxp->v_type == VDIR ||
    372 				    procfs_proc_is_linux_compat())
    373 					goto symlink;
    374 				vp->v_type = vxp->v_type;
    375 				break;
    376 			case DTYPE_PIPE:
    377 				vp->v_type = VFIFO;
    378 				break;
    379 			case DTYPE_SOCKET:
    380 				vp->v_type = VSOCK;
    381 				break;
    382 			case DTYPE_KQUEUE:
    383 			case DTYPE_MISC:
    384 			case DTYPE_SEM:
    385 			symlink:
    386 				pfs->pfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|
    387 				    S_IXGRP|S_IROTH|S_IXOTH;
    388 				vp->v_type = VLNK;
    389 				break;
    390 			default:
    391 				error = EOPNOTSUPP;
    392 				closef(fp);
    393 				goto bad;
    394 			}
    395 			closef(fp);
    396 		}
    397 		break;
    398 
    399 	case PFSfile:	/* /proc/N/file = -rw------- */
    400 	case PFSmem:	/* /proc/N/mem = -rw------- */
    401 	case PFSregs:	/* /proc/N/regs = -rw------- */
    402 	case PFSfpregs:	/* /proc/N/fpregs = -rw------- */
    403 		pfs->pfs_mode = S_IRUSR|S_IWUSR;
    404 		vp->v_type = VREG;
    405 		break;
    406 
    407 	case PFSnote:	/* /proc/N/note = --w------ */
    408 	case PFSnotepg:	/* /proc/N/notepg = --w------ */
    409 		pfs->pfs_mode = S_IWUSR;
    410 		vp->v_type = VREG;
    411 		break;
    412 
    413 	case PFSmap:		/* /proc/N/map = -r-------- */
    414 	case PFSmaps:		/* /proc/N/maps = -r-------- */
    415 	case PFSauxv:		/* /proc/N/auxv = -r-------- */
    416 	case PFSenviron:	/* /proc/N/environ = -r-------- */
    417 		pfs->pfs_mode = S_IRUSR;
    418 		vp->v_type = VREG;
    419 		break;
    420 
    421 	case PFSstatus:		/* /proc/N/status = -r--r--r-- */
    422 	case PFSstat:		/* /proc/N/stat = -r--r--r-- */
    423 	case PFScmdline:	/* /proc/N/cmdline = -r--r--r-- */
    424 	case PFSemul:		/* /proc/N/emul = -r--r--r-- */
    425 	case PFSmeminfo:	/* /proc/meminfo = -r--r--r-- */
    426 	case PFScpustat:	/* /proc/stat = -r--r--r-- */
    427 	case PFSdevices:	/* /proc/devices = -r--r--r-- */
    428 	case PFScpuinfo:	/* /proc/cpuinfo = -r--r--r-- */
    429 	case PFSuptime:		/* /proc/uptime = -r--r--r-- */
    430 	case PFSmounts:		/* /proc/mounts = -r--r--r-- */
    431 	case PFSloadavg:	/* /proc/loadavg = -r--r--r-- */
    432 	case PFSstatm:		/* /proc/N/statm = -r--r--r-- */
    433 	case PFSversion:	/* /proc/version = -r--r--r-- */
    434 	case PFSlimit:		/* /proc/N/limit = -r--r--r-- */
    435 	case PFSlimits:		/* /proc/N/limits = -r--r--r-- */
    436 		pfs->pfs_mode = S_IRUSR|S_IRGRP|S_IROTH;
    437 		vp->v_type = VREG;
    438 		break;
    439 
    440 	case PFSsys:	/* /proc/sys = dr-xr-xr-x */
    441 	case PFSsysfs:	/* /proc/sys/fs = dr-xr-xr-x */
    442 	case PFSmqueue:	/* /proc/sys/fs/mqueue = dr-xr-xr-x */
    443 	case PFSsysvipc:/* /proc/sysvipc = dr-xr-xr-x */
    444 		if (pfs->pfs_fd == -1) {
    445 			pfs->pfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|
    446 			    S_IROTH|S_IXOTH;
    447 			vp->v_type = VDIR;
    448 			break;
    449 		}
    450 		/*FALLTHROUGH*/
    451 	case PFSmq_msg_def:	/* /proc/sys/fs/mqueue/msg_default = -r--r--r-- */
    452 	case PFSmq_msg_max:	/* /proc/sys/fs/mqueue/msg_max = -r--r--r-- */
    453 	case PFSmq_siz_def:	/* /proc/sys/fs/mqueue/msgsize_default = -r--r--r-- */
    454 	case PFSmq_siz_max:	/* /proc/sys/fs/mqueue/msgsize_max = -r--r--r-- */
    455 	case PFSmq_qmax:	/* /proc/sys/fs/mqueue/queues_max = -r--r--r-- */
    456 	case PFSsysvipc_msg:	/* /proc/sysvipc/msg = -r--r--r-- */
    457 	case PFSsysvipc_sem:	/* /proc/sysvipc/sem = -r--r--r-- */
    458 	case PFSsysvipc_shm:	/* /proc/sysvipc/shm = -r--r--r-- */
    459 		pfs->pfs_mode = S_IRUSR|S_IRGRP|S_IROTH;
    460 		vp->v_type = VREG;
    461 		break;
    462 
    463 #ifdef __HAVE_PROCFS_MACHDEP
    464 	PROCFS_MACHDEP_NODETYPE_CASES
    465 		procfs_machdep_allocvp(vp);
    466 		break;
    467 #endif
    468 
    469 	default:
    470 		panic("procfs_allocvp");
    471 	}
    472 
    473 	mutex_enter(&procfs_hashlock);
    474 	LIST_INSERT_HEAD(procfs_hashhead(pfs->pfs_pid), pfs, pfs_hash);
    475 	mutex_exit(&procfs_hashlock);
    476 
    477 	uvm_vnp_setsize(vp, 0);
    478 	*new_key = &pfs->pfs_key;
    479 
    480 	return 0;
    481 
    482 bad:
    483 	vp->v_tag =VT_NON;
    484 	vp->v_type = VNON;
    485 	vp->v_op = NULL;
    486 	vp->v_data = NULL;
    487 	kmem_free(pfs, sizeof(*pfs));
    488 	return error;
    489 }
    490 
    491 void
    492 procfs_init(void)
    493 {
    494 
    495 }
    496 
    497 void
    498 procfs_reinit(void)
    499 {
    500 
    501 }
    502 
    503 void
    504 procfs_done(void)
    505 {
    506 
    507 }
    508 
    509 extern const struct vnodeopv_desc procfs_vnodeop_opv_desc;
    510 
    511 const struct vnodeopv_desc * const procfs_vnodeopv_descs[] = {
    512 	&procfs_vnodeop_opv_desc,
    513 	NULL,
    514 };
    515 
    516 struct vfsops procfs_vfsops = {
    517 	.vfs_name = MOUNT_PROCFS,
    518 	.vfs_min_mount_data = sizeof (struct procfs_args),
    519 	.vfs_mount = procfs_mount,
    520 	.vfs_start = procfs_start,
    521 	.vfs_unmount = procfs_unmount,
    522 	.vfs_root = procfs_root,
    523 	.vfs_quotactl = (void *)eopnotsupp,
    524 	.vfs_statvfs = procfs_statvfs,
    525 	.vfs_sync = procfs_sync,
    526 	.vfs_vget = procfs_vget,
    527 	.vfs_loadvnode = procfs_loadvnode,
    528 	.vfs_fhtovp = (void *)eopnotsupp,
    529 	.vfs_vptofh = (void *)eopnotsupp,
    530 	.vfs_init = procfs_init,
    531 	.vfs_reinit = procfs_reinit,
    532 	.vfs_done = procfs_done,
    533 	.vfs_snapshot = (void *)eopnotsupp,
    534 	.vfs_extattrctl = vfs_stdextattrctl,
    535 	.vfs_suspendctl = genfs_suspendctl,
    536 	.vfs_renamelock_enter = genfs_renamelock_enter,
    537 	.vfs_renamelock_exit = genfs_renamelock_exit,
    538 	.vfs_fsync = (void *)eopnotsupp,
    539 	.vfs_opv_descs = procfs_vnodeopv_descs
    540 };
    541 
    542 static void
    543 procfs_exechook_cb(struct proc *p, void *arg)
    544 {
    545 	struct hashhead *head;
    546 	struct pfsnode *pfs;
    547 	struct mount *mp;
    548 	struct pfskey key;
    549 	struct vnode *vp;
    550 	int error;
    551 
    552 	if (arg == PROCFS_EXEC_HOOK && !(p->p_flag & PK_SUGID))
    553 		return;
    554 
    555 	head = procfs_hashhead(p->p_pid);
    556 
    557 again:
    558 	mutex_enter(&procfs_hashlock);
    559 	LIST_FOREACH(pfs, head, pfs_hash) {
    560 		if (pfs->pfs_pid != p->p_pid)
    561 			continue;
    562 		mp = pfs->pfs_mount;
    563 		key = pfs->pfs_key;
    564 		vfs_ref(mp);
    565 		mutex_exit(&procfs_hashlock);
    566 
    567 		error = vcache_get(mp, &key, sizeof(key), &vp);
    568 		vfs_rele(mp);
    569 		if (error != 0)
    570 			goto again;
    571 		if (vrecycle(vp))
    572 			goto again;
    573 		do {
    574 			error = vfs_suspend(mp, 0);
    575 		} while (error == EINTR || error == ERESTART);
    576 		vgone(vp);
    577 		if (error == 0)
    578 			vfs_resume(mp);
    579 		goto again;
    580 	}
    581 	mutex_exit(&procfs_hashlock);
    582 }
    583 
    584 static int
    585 procfs_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
    586     void *arg0, void *arg1, void *arg2, void *arg3)
    587 {
    588 	struct proc *p;
    589 	struct pfsnode *pfs;
    590 	int result;
    591 
    592 	result = KAUTH_RESULT_DEFER;
    593 	p = arg0;
    594 	pfs = arg1;
    595 
    596 	if (action != KAUTH_PROCESS_PROCFS)
    597 		return result;
    598 
    599 	switch (pfs->pfs_type) {
    600 	case PFSregs:
    601 	case PFSfpregs:
    602 	case PFSmem:
    603 		if (kauth_cred_getuid(cred) != kauth_cred_getuid(p->p_cred) ||
    604 		    ISSET(p->p_flag, PK_SUGID))
    605 			break;
    606 
    607 		/*FALLTHROUGH*/
    608 	default:
    609 		result = KAUTH_RESULT_ALLOW;
    610 		break;
    611 	}
    612 
    613 	return result;
    614 }
    615 
    616 SYSCTL_SETUP(procfs_sysctl_setup, "procfs sysctl")
    617 {
    618 
    619 	sysctl_createv(clog, 0, NULL, NULL,
    620 		       CTLFLAG_PERMANENT,
    621 		       CTLTYPE_NODE, "procfs",
    622 		       SYSCTL_DESCR("Process file system"),
    623 		       NULL, 0, NULL, 0,
    624 		       CTL_VFS, 12, CTL_EOL);
    625 	/*
    626 	 * XXX the "12" above could be dynamic, thereby eliminating
    627 	 * one more instance of the "number to vfs" mapping problem,
    628 	 * but "12" is the order as taken from sys/mount.h
    629 	 */
    630 }
    631 
    632 static int
    633 procfs_modcmd(modcmd_t cmd, void *arg)
    634 {
    635 	int error;
    636 
    637 	switch (cmd) {
    638 	case MODULE_CMD_INIT:
    639 		error = vfs_attach(&procfs_vfsops);
    640 		if (error != 0)
    641 			break;
    642 
    643 		procfs_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS,
    644 		    procfs_listener_cb, NULL);
    645 
    646 		procfs_exechook = exechook_establish(procfs_exechook_cb,
    647 		    PROCFS_EXEC_HOOK);
    648 		procfs_exithook = exithook_establish(procfs_exechook_cb,
    649 		    PROCFS_EXIT_HOOK);
    650 
    651 		mutex_init(&procfs_hashlock, MUTEX_DEFAULT, IPL_NONE);
    652 		procfs_hashtab = hashinit(PROCFS_HASHSIZE, HASH_LIST, true,
    653 		    &procfs_hashmask);
    654 
    655 		break;
    656 	case MODULE_CMD_FINI:
    657 		error = vfs_detach(&procfs_vfsops);
    658 		if (error != 0)
    659 			break;
    660 		kauth_unlisten_scope(procfs_listener);
    661 		exechook_disestablish(procfs_exechook);
    662 		exithook_disestablish(procfs_exithook);
    663 		mutex_destroy(&procfs_hashlock);
    664 		hashdone(procfs_hashtab, HASH_LIST, procfs_hashmask);
    665 		break;
    666 	default:
    667 		error = ENOTTY;
    668 		break;
    669 	}
    670 
    671 	return (error);
    672 }
    673