1 /* 2 * Copyright (c) 1993 Jan-Simon Pendry 3 * Copyright (c) 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Jan-Simon Pendry. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)procfs_subr.c 8.6 (Berkeley) 5/14/95 38 * 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 $ 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/sysctl.h> 46 #include <sys/proc.h> 47 #include <sys/mount.h> 48 #include <sys/vnode.h> 49 #include <sys/malloc.h> 50 51 #include <vfs/procfs/procfs.h> 52 53 #define PFS_HSIZE 256 54 #define PFS_HMASK (PFS_HSIZE - 1) 55 56 static struct pfsnode *pfshead[PFS_HSIZE]; 57 static int pfsvplock; 58 59 #define PFSHASH(pid) &pfshead[(pid) & PFS_HMASK] 60 61 /* 62 * Allocate a pfsnode/vnode pair. If no error occurs the returned vnode 63 * will be referenced and exclusively locked. 64 * 65 * The pid, pfs_type, and mount point uniquely identify a pfsnode. 66 * The mount point is needed because someone might mount this filesystem 67 * twice. 68 * 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. 72 * 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. 78 * 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. 82 */ 83 int 84 procfs_allocvp(struct mount *mp, struct vnode **vpp, long pid, pfstype pfs_type) 85 { 86 struct pfsnode *pfs; 87 struct vnode *vp; 88 struct pfsnode **pp; 89 int error; 90 91 pp = PFSHASH(pid); 92 loop: 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) { 96 vp = PFSTOV(pfs); 97 if (vget(vp, LK_EXCLUSIVE)) 98 goto loop; 99 100 /* 101 * Make sure the vnode is still in the cache after 102 * getting the interlock to avoid racing a free. 103 */ 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) { 109 break; 110 } 111 } 112 if (pfs == NULL || PFSTOV(pfs) != vp) { 113 vput(vp); 114 goto loop; 115 116 } 117 *vpp = vp; 118 return (0); 119 } 120 } 121 122 /* 123 * otherwise lock the vp list while we call getnewvnode 124 * since that can block. 125 */ 126 if (pfsvplock & PROCFS_LOCKED) { 127 pfsvplock |= PROCFS_WANT; 128 (void) tsleep((caddr_t) &pfsvplock, 0, "pfsavp", 0); 129 goto loop; 130 } 131 pfsvplock |= PROCFS_LOCKED; 132 133 /* 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. 137 * 138 * XXX this may not matter anymore since getnewvnode now returns 139 * a VX locked vnode. 140 */ 141 MALLOC(pfs, struct pfsnode *, sizeof(struct pfsnode), M_TEMP, M_WAITOK); 142 143 error = getnewvnode(VT_PROCFS, mp, vpp, 0, 0); 144 if (error) { 145 kfree(pfs, M_TEMP); 146 goto out; 147 } 148 vp = *vpp; 149 150 vp->v_data = pfs; 151 152 pfs->pfs_next = 0; 153 pfs->pfs_pid = (pid_t) pid; 154 pfs->pfs_type = pfs_type; 155 pfs->pfs_vnode = vp; 156 pfs->pfs_flags = 0; 157 pfs->pfs_lockowner = 0; 158 pfs->pfs_fileno = PROCFS_FILENO(pid, pfs_type); 159 160 switch (pfs_type) { 161 case Proot: /* /proc = dr-xr-xr-x */ 162 pfs->pfs_mode = (VREAD|VEXEC) | 163 (VREAD|VEXEC) >> 3 | 164 (VREAD|VEXEC) >> 6; 165 vp->v_type = VDIR; 166 vp->v_flag = VROOT; 167 break; 168 169 case Pcurproc: /* /proc/curproc = lr--r--r-- */ 170 pfs->pfs_mode = (VREAD) | 171 (VREAD >> 3) | 172 (VREAD >> 6); 173 vp->v_type = VLNK; 174 break; 175 176 case Pproc: 177 pfs->pfs_mode = (VREAD|VEXEC) | 178 (VREAD|VEXEC) >> 3 | 179 (VREAD|VEXEC) >> 6; 180 vp->v_type = VDIR; 181 break; 182 183 case Pfile: 184 pfs->pfs_mode = (VREAD|VEXEC) | 185 (VREAD|VEXEC) >> 3 | 186 (VREAD|VEXEC) >> 6; 187 vp->v_type = VLNK; 188 break; 189 190 case Pmem: 191 pfs->pfs_mode = (VREAD|VWRITE); 192 vp->v_type = VREG; 193 break; 194 195 case Pregs: 196 case Pfpregs: 197 case Pdbregs: 198 pfs->pfs_mode = (VREAD|VWRITE); 199 vp->v_type = VREG; 200 break; 201 202 case Pctl: 203 case Pnote: 204 case Pnotepg: 205 pfs->pfs_mode = (VWRITE); 206 vp->v_type = VREG; 207 break; 208 209 case Ptype: 210 case Pmap: 211 case Pstatus: 212 case Pcmdline: 213 case Prlimit: 214 pfs->pfs_mode = (VREAD) | 215 (VREAD >> 3) | 216 (VREAD >> 6); 217 vp->v_type = VREG; 218 break; 219 220 default: 221 panic("procfs_allocvp"); 222 } 223 224 /* add to procfs vnode list */ 225 pfs->pfs_next = *pp; 226 *pp = pfs; 227 228 out: 229 pfsvplock &= ~PROCFS_LOCKED; 230 231 if (pfsvplock & PROCFS_WANT) { 232 pfsvplock &= ~PROCFS_WANT; 233 wakeup((caddr_t) &pfsvplock); 234 } 235 236 return (error); 237 } 238 239 int 240 procfs_freevp(struct vnode *vp) 241 { 242 struct pfsnode **pfspp; 243 struct pfsnode *pfs; 244 245 pfs = VTOPFS(vp); 246 vp->v_data = NULL; 247 248 pfspp = PFSHASH(pfs->pfs_pid); 249 while (*pfspp != pfs && *pfspp) 250 pfspp = &(*pfspp)->pfs_next; 251 KKASSERT(*pfspp); 252 *pfspp = pfs->pfs_next; 253 pfs->pfs_next = NULL; 254 kfree(pfs, M_TEMP); 255 return (0); 256 } 257 258 int 259 procfs_rw(struct vop_read_args *ap) 260 { 261 struct vnode *vp = ap->a_vp; 262 struct uio *uio = ap->a_uio; 263 struct thread *curtd = uio->uio_td; 264 struct proc *curp; 265 struct pfsnode *pfs = VTOPFS(vp); 266 struct proc *p; 267 struct lwp *lp; 268 int rtval; 269 270 if (curtd == NULL) 271 return (EINVAL); 272 if ((curp = curtd->td_proc) == NULL) /* XXX */ 273 return (EINVAL); 274 275 p = PFIND(pfs->pfs_pid); 276 if (p == NULL) 277 return (EINVAL); 278 if (p->p_pid == 1 && securelevel > 0 && uio->uio_rw == UIO_WRITE) 279 return (EACCES); 280 /* XXX lwp */ 281 lp = FIRST_LWP_IN_PROC(p); 282 LWPHOLD(lp); 283 284 while (pfs->pfs_lockowner) { 285 tsleep(&pfs->pfs_lockowner, 0, "pfslck", 0); 286 } 287 pfs->pfs_lockowner = curproc->p_pid; 288 289 switch (pfs->pfs_type) { 290 case Pnote: 291 case Pnotepg: 292 rtval = procfs_donote(curp, lp, pfs, uio); 293 break; 294 295 case Pregs: 296 rtval = procfs_doregs(curp, lp, pfs, uio); 297 break; 298 299 case Pfpregs: 300 rtval = procfs_dofpregs(curp, lp, pfs, uio); 301 break; 302 303 case Pdbregs: 304 rtval = procfs_dodbregs(curp, lp, pfs, uio); 305 break; 306 307 case Pctl: 308 rtval = procfs_doctl(curp, lp, pfs, uio); 309 break; 310 311 case Pstatus: 312 rtval = procfs_dostatus(curp, lp, pfs, uio); 313 break; 314 315 case Pmap: 316 rtval = procfs_domap(curp, lp, pfs, uio); 317 break; 318 319 case Pmem: 320 rtval = procfs_domem(curp, lp, pfs, uio); 321 break; 322 323 case Ptype: 324 rtval = procfs_dotype(curp, lp, pfs, uio); 325 break; 326 327 case Pcmdline: 328 rtval = procfs_docmdline(curp, lp, pfs, uio); 329 break; 330 331 case Prlimit: 332 rtval = procfs_dorlimit(curp, lp, pfs, uio); 333 break; 334 335 default: 336 rtval = EOPNOTSUPP; 337 break; 338 } 339 LWPRELE(lp); 340 pfs->pfs_lockowner = 0; 341 wakeup(&pfs->pfs_lockowner); 342 return rtval; 343 } 344 345 /* 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. 350 * 351 * Returns 0 on success or the following errors 352 * 353 * EINVAL: file offset is non-zero. 354 * EMSGSIZE: message is longer than kernel buffer 355 * EFAULT: user i/o buffer is not addressable 356 */ 357 int 358 vfs_getuserstr(struct uio *uio, char *buf, int *buflenp) 359 { 360 int xlen; 361 int error; 362 363 if (uio->uio_offset != 0) 364 return (EINVAL); 365 366 xlen = *buflenp; 367 368 /* must be able to read the whole string in one go */ 369 if (xlen < uio->uio_resid) 370 return (EMSGSIZE); 371 xlen = uio->uio_resid; 372 373 if ((error = uiomove(buf, xlen, uio)) != 0) 374 return (error); 375 376 /* allow multiple writes without seeks */ 377 uio->uio_offset = 0; 378 379 /* cleanup string and remove trailing newline */ 380 buf[xlen] = '\0'; 381 xlen = strlen(buf); 382 if (xlen > 0 && buf[xlen-1] == '\n') 383 buf[--xlen] = '\0'; 384 *buflenp = xlen; 385 386 return (0); 387 } 388 389 vfs_namemap_t * 390 vfs_findname(vfs_namemap_t *nm, char *buf, int buflen) 391 { 392 393 for (; nm->nm_name; nm++) 394 if (bcmp(buf, nm->nm_name, buflen+1) == 0) 395 return (nm); 396 397 return (0); 398 } 399 400 void 401 procfs_exit(struct thread *td) 402 { 403 struct pfsnode *pfs; 404 struct vnode *vp; 405 pid_t pid; 406 407 KKASSERT(td->td_proc); 408 pid = td->td_proc->p_pid; 409 410 /* 411 * NOTE: We can't just vgone() the vnode any more, not while 412 * it may potentially still be active. This will clean 413 * the vp and clear the mount and cause the new VOP subsystem 414 * to assert or panic when someone tries to do an operation 415 * on an open (exited) procfs descriptor. 416 * 417 * Prevent further operations on this pid by setting pfs_pid to -1. 418 * Note that a pfs_pid of 0 is used for nodes which do not track 419 * any particular pid. 420 * 421 * Use vx_get() to properly ref/lock a vp which may not have any 422 * refs and which may or may not already be reclaimed. vx_put() 423 * will then properly deactivate it and cause it to be recycled. 424 * 425 * The hash table can also get ripped out from under us when 426 * we block so take the easy way out and restart the scan. 427 */ 428 again: 429 pfs = *PFSHASH(pid); 430 while (pfs) { 431 if (pfs->pfs_pid == pid) { 432 vp = PFSTOV(pfs); 433 vx_get(vp); 434 pfs->pfs_pid |= PFS_DEAD; /* does not effect hash */ 435 vx_put(vp); 436 goto again; 437 } 438 pfs = pfs->pfs_next; 439 } 440 } 441 442