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kvm_proc.c revision 1.27
      1 /*	$NetBSD: kvm_proc.c,v 1.27 1998/09/09 00:31:25 thorpej Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Charles M. Hannum.
      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. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*-
     40  * Copyright (c) 1989, 1992, 1993
     41  *	The Regents of the University of California.  All rights reserved.
     42  *
     43  * This code is derived from software developed by the Computer Systems
     44  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
     45  * BG 91-66 and contributed to Berkeley.
     46  *
     47  * Redistribution and use in source and binary forms, with or without
     48  * modification, are permitted provided that the following conditions
     49  * are met:
     50  * 1. Redistributions of source code must retain the above copyright
     51  *    notice, this list of conditions and the following disclaimer.
     52  * 2. Redistributions in binary form must reproduce the above copyright
     53  *    notice, this list of conditions and the following disclaimer in the
     54  *    documentation and/or other materials provided with the distribution.
     55  * 3. All advertising materials mentioning features or use of this software
     56  *    must display the following acknowledgement:
     57  *	This product includes software developed by the University of
     58  *	California, Berkeley and its contributors.
     59  * 4. Neither the name of the University nor the names of its contributors
     60  *    may be used to endorse or promote products derived from this software
     61  *    without specific prior written permission.
     62  *
     63  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     64  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     65  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     66  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     67  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     68  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     69  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     70  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     71  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     72  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     73  * SUCH DAMAGE.
     74  */
     75 
     76 #include <sys/cdefs.h>
     77 #if defined(LIBC_SCCS) && !defined(lint)
     78 #if 0
     79 static char sccsid[] = "@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93";
     80 #else
     81 __RCSID("$NetBSD: kvm_proc.c,v 1.27 1998/09/09 00:31:25 thorpej Exp $");
     82 #endif
     83 #endif /* LIBC_SCCS and not lint */
     84 
     85 /*
     86  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
     87  * users of this code, so we've factored it out into a separate module.
     88  * Thus, we keep this grunge out of the other kvm applications (i.e.,
     89  * most other applications are interested only in open/close/read/nlist).
     90  */
     91 
     92 #include <sys/param.h>
     93 #include <sys/user.h>
     94 #include <sys/proc.h>
     95 #include <sys/exec.h>
     96 #include <sys/stat.h>
     97 #include <sys/ioctl.h>
     98 #include <sys/tty.h>
     99 #include <stdlib.h>
    100 #include <string.h>
    101 #include <unistd.h>
    102 #include <nlist.h>
    103 #include <kvm.h>
    104 
    105 #include <vm/vm.h>
    106 #include <vm/vm_param.h>
    107 #include <vm/swap_pager.h>
    108 
    109 #if defined(UVM)
    110 #include <uvm/uvm_extern.h>
    111 #endif
    112 
    113 #include <sys/sysctl.h>
    114 
    115 #include <limits.h>
    116 #include <db.h>
    117 #include <paths.h>
    118 
    119 #include "kvm_private.h"
    120 
    121 #define KREAD(kd, addr, obj) \
    122 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
    123 
    124 char		*_kvm_uread __P((kvm_t *, const struct proc *, u_long, u_long *));
    125 #if !defined(UVM)
    126 int		_kvm_coreinit __P((kvm_t *));
    127 int		_kvm_readfromcore __P((kvm_t *, u_long, u_long));
    128 int		_kvm_readfrompager __P((kvm_t *, struct vm_object *, u_long));
    129 #endif
    130 ssize_t		kvm_uread __P((kvm_t *, const struct proc *, u_long, char *,
    131 		    size_t));
    132 
    133 static char	**kvm_argv __P((kvm_t *, const struct proc *, u_long, int,
    134 		    int));
    135 static int	kvm_deadprocs __P((kvm_t *, int, int, u_long, u_long, u_long,
    136 		    int));
    137 static char	**kvm_doargv __P((kvm_t *, const struct kinfo_proc *, int,
    138 		    void (*)(struct ps_strings *, u_long *, int *)));
    139 static int	kvm_proclist __P((kvm_t *, int, int, struct proc *,
    140 		    struct kinfo_proc *, int));
    141 static int	proc_verify __P((kvm_t *, u_long, const struct proc *));
    142 static void	ps_str_a __P((struct ps_strings *, u_long *, int *));
    143 static void	ps_str_e __P((struct ps_strings *, u_long *, int *));
    144 
    145 char *
    146 _kvm_uread(kd, p, va, cnt)
    147 	kvm_t *kd;
    148 	const struct proc *p;
    149 	u_long va;
    150 	u_long *cnt;
    151 {
    152 	u_long addr, head;
    153 	u_long offset;
    154 	struct vm_map_entry vme;
    155 #if defined(UVM)
    156 	struct vm_amap amap;
    157 	struct vm_anon *anonp, anon;
    158 	struct vm_page pg;
    159 	int slot;
    160 #else
    161 	struct vm_object vmo;
    162 	int rv;
    163 #endif
    164 
    165 	if (kd->swapspc == 0) {
    166 		kd->swapspc = (char *)_kvm_malloc(kd, kd->nbpg);
    167 		if (kd->swapspc == 0)
    168 			return (0);
    169 	}
    170 
    171 	/*
    172 	 * Look through the address map for the memory object
    173 	 * that corresponds to the given virtual address.
    174 	 * The header just has the entire valid range.
    175 	 */
    176 	head = (u_long)&p->p_vmspace->vm_map.header;
    177 	addr = head;
    178 	while (1) {
    179 		if (KREAD(kd, addr, &vme))
    180 			return (0);
    181 
    182 #if defined(UVM)
    183 		if (va >= vme.start && va < vme.end &&
    184 		    vme.aref.ar_amap != NULL)
    185 			break;
    186 
    187 #else
    188 		if (va >= vme.start && va < vme.end &&
    189 		    vme.object.vm_object != 0)
    190 			break;
    191 #endif
    192 
    193 		addr = (u_long)vme.next;
    194 		if (addr == head)
    195 			return (0);
    196 
    197 	}
    198 #if defined(UVM)
    199 
    200 	/*
    201 	 * we found the map entry, now to find the object...
    202 	 */
    203 	if (vme.aref.ar_amap == NULL)
    204 		return NULL;
    205 
    206 	addr = (u_long)vme.aref.ar_amap;
    207 	if (KREAD(kd, addr, &amap))
    208 		return NULL;
    209 
    210 	offset = va - vme.start;
    211 	slot = offset / kd->nbpg + vme.aref.ar_slotoff;
    212 	/* sanity-check slot number */
    213 	if (slot  > amap.am_nslot)
    214 		return NULL;
    215 
    216 	addr = (u_long)amap.am_anon + (offset / kd->nbpg) * sizeof(anonp);
    217 	if (KREAD(kd, addr, &anonp))
    218 		return NULL;
    219 
    220 	addr = (u_long)anonp;
    221 	if (KREAD(kd, addr, &anon))
    222 		return NULL;
    223 
    224 	addr = (u_long)anon.u.an_page;
    225 	if (addr) {
    226 		if (KREAD(kd, addr, &pg))
    227 			return NULL;
    228 
    229 		if (pread(kd->pmfd, kd->swapspc, kd->nbpg,
    230 		    (off_t)pg.phys_addr) != kd->nbpg)
    231 			return NULL;
    232 	}
    233 	else {
    234 		if (pread(kd->swfd, kd->swapspc, kd->nbpg,
    235 		    (off_t)(anon.an_swslot * kd->nbpg)) != kd->nbpg)
    236 			return NULL;
    237 	}
    238 #else
    239 	/*
    240 	 * We found the right object -- follow shadow links.
    241 	 */
    242 	offset = va - vme.start + vme.offset;
    243 	addr = (u_long)vme.object.vm_object;
    244 
    245 	while (1) {
    246 		/* Try reading the page from core first. */
    247 		if ((rv = _kvm_readfromcore(kd, addr, offset)))
    248 			break;
    249 
    250 		if (KREAD(kd, addr, &vmo))
    251 			return (0);
    252 
    253 		/* If there is a pager here, see if it has the page. */
    254 		if (vmo.pager != 0 &&
    255 		    (rv = _kvm_readfrompager(kd, &vmo, offset)))
    256 			break;
    257 
    258 		/* Move down the shadow chain. */
    259 		addr = (u_long)vmo.shadow;
    260 		if (addr == 0)
    261 			return (0);
    262 		offset += vmo.shadow_offset;
    263 	}
    264 
    265 	if (rv == -1)
    266 		return (0);
    267 #endif
    268 
    269 	/* Found the page. */
    270 	offset %= kd->nbpg;
    271 	*cnt = kd->nbpg - offset;
    272 	return (&kd->swapspc[offset]);
    273 }
    274 
    275 #if !defined(UVM)
    276 
    277 #define	vm_page_hash(kd, object, offset) \
    278 	(((u_long)object + (u_long)(offset / kd->nbpg)) & kd->vm_page_hash_mask)
    279 
    280 int
    281 _kvm_coreinit(kd)
    282 	kvm_t *kd;
    283 {
    284 	struct nlist nlist[3];
    285 
    286 	nlist[0].n_name = "_vm_page_buckets";
    287 	nlist[1].n_name = "_vm_page_hash_mask";
    288 	nlist[2].n_name = 0;
    289 	if (kvm_nlist(kd, nlist) != 0)
    290 		return (-1);
    291 
    292 	if (KREAD(kd, nlist[0].n_value, &kd->vm_page_buckets) ||
    293 	    KREAD(kd, nlist[1].n_value, &kd->vm_page_hash_mask))
    294 		return (-1);
    295 
    296 	return (0);
    297 }
    298 
    299 int
    300 _kvm_readfromcore(kd, object, offset)
    301 	kvm_t *kd;
    302 	u_long object, offset;
    303 {
    304 	u_long addr;
    305 	struct pglist bucket;
    306 	struct vm_page mem;
    307 	off_t seekpoint;
    308 
    309 	if (kd->vm_page_buckets == 0 &&
    310 	    _kvm_coreinit(kd))
    311 		return (-1);
    312 
    313 	addr = (u_long)&kd->vm_page_buckets[vm_page_hash(kd, object, offset)];
    314 	if (KREAD(kd, addr, &bucket))
    315 		return (-1);
    316 
    317 	addr = (u_long)bucket.tqh_first;
    318 	offset &= ~(kd->nbpg -1);
    319 	while (1) {
    320 		if (addr == 0)
    321 			return (0);
    322 
    323 		if (KREAD(kd, addr, &mem))
    324 			return (-1);
    325 
    326 		if ((u_long)mem.object == object &&
    327 		    (u_long)mem.offset == offset)
    328 			break;
    329 
    330 		addr = (u_long)mem.hashq.tqe_next;
    331 	}
    332 
    333 	seekpoint = mem.phys_addr;
    334 
    335 	if (pread(kd->pmfd, kd->swapspc, kd->nbpg, seekpoint) != kd->nbpg)
    336 		return (-1);
    337 
    338 	return (1);
    339 }
    340 
    341 int
    342 _kvm_readfrompager(kd, vmop, offset)
    343 	kvm_t *kd;
    344 	struct vm_object *vmop;
    345 	u_long offset;
    346 {
    347 	u_long addr;
    348 	struct pager_struct pager;
    349 	struct swpager swap;
    350 	int ix;
    351 	struct swblock swb;
    352 	off_t seekpoint;
    353 
    354 	/* Read in the pager info and make sure it's a swap device. */
    355 	addr = (u_long)vmop->pager;
    356 	if (KREAD(kd, addr, &pager) || pager.pg_type != PG_SWAP)
    357 		return (-1);
    358 
    359 	/* Read in the swap_pager private data. */
    360 	addr = (u_long)pager.pg_data;
    361 	if (KREAD(kd, addr, &swap))
    362 		return (-1);
    363 
    364 	/*
    365 	 * Calculate the paging offset, and make sure it's within the
    366 	 * bounds of the pager.
    367 	 */
    368 	offset += vmop->paging_offset;
    369 	ix = offset / dbtob(swap.sw_bsize);
    370 #if 0
    371 	if (swap.sw_blocks == 0 || ix >= swap.sw_nblocks)
    372 		return (-1);
    373 #else
    374 	if (swap.sw_blocks == 0 || ix >= swap.sw_nblocks) {
    375 		int i;
    376 		printf("BUG BUG BUG BUG:\n");
    377 		printf("object %p offset %lx pgoffset %lx ",
    378 		    vmop, offset - vmop->paging_offset,
    379 		    (u_long)vmop->paging_offset);
    380 		printf("pager %p swpager %p\n",
    381 		    vmop->pager, pager.pg_data);
    382 		printf("osize %lx bsize %x blocks %p nblocks %x\n",
    383 		    (u_long)swap.sw_osize, swap.sw_bsize, swap.sw_blocks,
    384 		    swap.sw_nblocks);
    385 		for (i = 0; i < swap.sw_nblocks; i++) {
    386 			addr = (u_long)&swap.sw_blocks[i];
    387 			if (KREAD(kd, addr, &swb))
    388 				return (0);
    389 			printf("sw_blocks[%d]: block %x mask %x\n", i,
    390 			    swb.swb_block, swb.swb_mask);
    391 		}
    392 		return (-1);
    393 	}
    394 #endif
    395 
    396 	/* Read in the swap records. */
    397 	addr = (u_long)&swap.sw_blocks[ix];
    398 	if (KREAD(kd, addr, &swb))
    399 		return (-1);
    400 
    401 	/* Calculate offset within pager. */
    402 	offset %= dbtob(swap.sw_bsize);
    403 
    404 	/* Check that the page is actually present. */
    405 	if ((swb.swb_mask & (1 << (offset / kd->nbpg))) == 0)
    406 		return (0);
    407 
    408 	if (!ISALIVE(kd))
    409 		return (-1);
    410 
    411 	/* Calculate the physical address and read the page. */
    412 	seekpoint = dbtob(swb.swb_block) + (offset & ~(kd->nbpg -1));
    413 
    414 	if (pread(kd->swfd, kd->swapspc, kd->nbpg, seekpoint) != kd->nbpg)
    415 		return (-1);
    416 
    417 	return (1);
    418 }
    419 #endif /* !defined(UVM) */
    420 
    421 /*
    422  * Read proc's from memory file into buffer bp, which has space to hold
    423  * at most maxcnt procs.
    424  */
    425 static int
    426 kvm_proclist(kd, what, arg, p, bp, maxcnt)
    427 	kvm_t *kd;
    428 	int what, arg;
    429 	struct proc *p;
    430 	struct kinfo_proc *bp;
    431 	int maxcnt;
    432 {
    433 	int cnt = 0;
    434 	struct eproc eproc;
    435 	struct pgrp pgrp;
    436 	struct session sess;
    437 	struct tty tty;
    438 	struct proc proc;
    439 
    440 	for (; cnt < maxcnt && p != NULL; p = proc.p_list.le_next) {
    441 		if (KREAD(kd, (u_long)p, &proc)) {
    442 			_kvm_err(kd, kd->program, "can't read proc at %x", p);
    443 			return (-1);
    444 		}
    445 		if (KREAD(kd, (u_long)proc.p_cred, &eproc.e_pcred) == 0)
    446 			(void)KREAD(kd, (u_long)eproc.e_pcred.pc_ucred,
    447 			      &eproc.e_ucred);
    448 
    449 		switch(what) {
    450 
    451 		case KERN_PROC_PID:
    452 			if (proc.p_pid != (pid_t)arg)
    453 				continue;
    454 			break;
    455 
    456 		case KERN_PROC_UID:
    457 			if (eproc.e_ucred.cr_uid != (uid_t)arg)
    458 				continue;
    459 			break;
    460 
    461 		case KERN_PROC_RUID:
    462 			if (eproc.e_pcred.p_ruid != (uid_t)arg)
    463 				continue;
    464 			break;
    465 		}
    466 		/*
    467 		 * We're going to add another proc to the set.  If this
    468 		 * will overflow the buffer, assume the reason is because
    469 		 * nprocs (or the proc list) is corrupt and declare an error.
    470 		 */
    471 		if (cnt >= maxcnt) {
    472 			_kvm_err(kd, kd->program, "nprocs corrupt");
    473 			return (-1);
    474 		}
    475 		/*
    476 		 * gather eproc
    477 		 */
    478 		eproc.e_paddr = p;
    479 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
    480 			_kvm_err(kd, kd->program, "can't read pgrp at %x",
    481 				 proc.p_pgrp);
    482 			return (-1);
    483 		}
    484 		eproc.e_sess = pgrp.pg_session;
    485 		eproc.e_pgid = pgrp.pg_id;
    486 		eproc.e_jobc = pgrp.pg_jobc;
    487 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
    488 			_kvm_err(kd, kd->program, "can't read session at %x",
    489 				pgrp.pg_session);
    490 			return (-1);
    491 		}
    492 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
    493 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
    494 				_kvm_err(kd, kd->program,
    495 					 "can't read tty at %x", sess.s_ttyp);
    496 				return (-1);
    497 			}
    498 			eproc.e_tdev = tty.t_dev;
    499 			eproc.e_tsess = tty.t_session;
    500 			if (tty.t_pgrp != NULL) {
    501 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
    502 					_kvm_err(kd, kd->program,
    503 						 "can't read tpgrp at &x",
    504 						tty.t_pgrp);
    505 					return (-1);
    506 				}
    507 				eproc.e_tpgid = pgrp.pg_id;
    508 			} else
    509 				eproc.e_tpgid = -1;
    510 		} else
    511 			eproc.e_tdev = NODEV;
    512 		eproc.e_flag = sess.s_ttyvp ? EPROC_CTTY : 0;
    513 		if (sess.s_leader == p)
    514 			eproc.e_flag |= EPROC_SLEADER;
    515 		if (proc.p_wmesg)
    516 			(void)kvm_read(kd, (u_long)proc.p_wmesg,
    517 			    eproc.e_wmesg, WMESGLEN);
    518 
    519 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
    520 		    (char *)&eproc.e_vm, sizeof(eproc.e_vm));
    521 
    522 		eproc.e_xsize = eproc.e_xrssize = 0;
    523 		eproc.e_xccount = eproc.e_xswrss = 0;
    524 
    525 		switch (what) {
    526 
    527 		case KERN_PROC_PGRP:
    528 			if (eproc.e_pgid != (pid_t)arg)
    529 				continue;
    530 			break;
    531 
    532 		case KERN_PROC_TTY:
    533 			if ((proc.p_flag & P_CONTROLT) == 0 ||
    534 			     eproc.e_tdev != (dev_t)arg)
    535 				continue;
    536 			break;
    537 		}
    538 		memcpy(&bp->kp_proc, &proc, sizeof(proc));
    539 		memcpy(&bp->kp_eproc, &eproc, sizeof(eproc));
    540 		++bp;
    541 		++cnt;
    542 	}
    543 	return (cnt);
    544 }
    545 
    546 /*
    547  * Build proc info array by reading in proc list from a crash dump.
    548  * Return number of procs read.  maxcnt is the max we will read.
    549  */
    550 static int
    551 kvm_deadprocs(kd, what, arg, a_allproc, a_deadproc, a_zombproc, maxcnt)
    552 	kvm_t *kd;
    553 	int what, arg;
    554 	u_long a_allproc;
    555 	u_long a_deadproc;
    556 	u_long a_zombproc;
    557 	int maxcnt;
    558 {
    559 	struct kinfo_proc *bp = kd->procbase;
    560 	int acnt, dcnt, zcnt;
    561 	struct proc *p;
    562 
    563 	if (KREAD(kd, a_allproc, &p)) {
    564 		_kvm_err(kd, kd->program, "cannot read allproc");
    565 		return (-1);
    566 	}
    567 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
    568 	if (acnt < 0)
    569 		return (acnt);
    570 
    571 	if (KREAD(kd, a_deadproc, &p)) {
    572 		_kvm_err(kd, kd->program, "cannot read deadproc");
    573 		return (-1);
    574 	}
    575 
    576 	dcnt = kvm_proclist(kd, what, arg, p, bp, maxcnt - acnt);
    577 	if (dcnt < 0)
    578 		dcnt = 0;
    579 
    580 	if (KREAD(kd, a_zombproc, &p)) {
    581 		_kvm_err(kd, kd->program, "cannot read zombproc");
    582 		return (-1);
    583 	}
    584 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt,
    585 	    maxcnt - (acnt + dcnt));
    586 	if (zcnt < 0)
    587 		zcnt = 0;
    588 
    589 	return (acnt + zcnt);
    590 }
    591 
    592 struct kinfo_proc *
    593 kvm_getprocs(kd, op, arg, cnt)
    594 	kvm_t *kd;
    595 	int op, arg;
    596 	int *cnt;
    597 {
    598 	size_t size;
    599 	int mib[4], st, nprocs;
    600 
    601 	if (kd->procbase != 0) {
    602 		free((void *)kd->procbase);
    603 		/*
    604 		 * Clear this pointer in case this call fails.  Otherwise,
    605 		 * kvm_close() will free it again.
    606 		 */
    607 		kd->procbase = 0;
    608 	}
    609 	if (ISALIVE(kd)) {
    610 		size = 0;
    611 		mib[0] = CTL_KERN;
    612 		mib[1] = KERN_PROC;
    613 		mib[2] = op;
    614 		mib[3] = arg;
    615 		st = sysctl(mib, 4, NULL, &size, NULL, 0);
    616 		if (st == -1) {
    617 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
    618 			return (0);
    619 		}
    620 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
    621 		if (kd->procbase == 0)
    622 			return (0);
    623 		st = sysctl(mib, 4, kd->procbase, &size, NULL, 0);
    624 		if (st == -1) {
    625 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
    626 			return (0);
    627 		}
    628 		if (size % sizeof(struct kinfo_proc) != 0) {
    629 			_kvm_err(kd, kd->program,
    630 				"proc size mismatch (%d total, %d chunks)",
    631 				size, sizeof(struct kinfo_proc));
    632 			return (0);
    633 		}
    634 		nprocs = size / sizeof(struct kinfo_proc);
    635 	} else {
    636 		struct nlist nl[5], *p;
    637 
    638 		nl[0].n_name = "_nprocs";
    639 		nl[1].n_name = "_allproc";
    640 		nl[2].n_name = "_deadproc";
    641 		nl[3].n_name = "_zombproc";
    642 		nl[4].n_name = 0;
    643 
    644 		if (kvm_nlist(kd, nl) != 0) {
    645 			for (p = nl; p->n_type != 0; ++p)
    646 				;
    647 			_kvm_err(kd, kd->program,
    648 				 "%s: no such symbol", p->n_name);
    649 			return (0);
    650 		}
    651 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
    652 			_kvm_err(kd, kd->program, "can't read nprocs");
    653 			return (0);
    654 		}
    655 		size = nprocs * sizeof(struct kinfo_proc);
    656 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
    657 		if (kd->procbase == 0)
    658 			return (0);
    659 
    660 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
    661 		    nl[2].n_value, nl[3].n_value, nprocs);
    662 #ifdef notdef
    663 		size = nprocs * sizeof(struct kinfo_proc);
    664 		(void)realloc(kd->procbase, size);
    665 #endif
    666 	}
    667 	*cnt = nprocs;
    668 	return (kd->procbase);
    669 }
    670 
    671 void
    672 _kvm_freeprocs(kd)
    673 	kvm_t *kd;
    674 {
    675 	if (kd->procbase) {
    676 		free(kd->procbase);
    677 		kd->procbase = 0;
    678 	}
    679 }
    680 
    681 void *
    682 _kvm_realloc(kd, p, n)
    683 	kvm_t *kd;
    684 	void *p;
    685 	size_t n;
    686 {
    687 	void *np = (void *)realloc(p, n);
    688 
    689 	if (np == 0)
    690 		_kvm_err(kd, kd->program, "out of memory");
    691 	return (np);
    692 }
    693 
    694 #ifndef MAX
    695 #define MAX(a, b) ((a) > (b) ? (a) : (b))
    696 #endif
    697 
    698 /*
    699  * Read in an argument vector from the user address space of process p.
    700  * addr if the user-space base address of narg null-terminated contiguous
    701  * strings.  This is used to read in both the command arguments and
    702  * environment strings.  Read at most maxcnt characters of strings.
    703  */
    704 static char **
    705 kvm_argv(kd, p, addr, narg, maxcnt)
    706 	kvm_t *kd;
    707 	const struct proc *p;
    708 	u_long addr;
    709 	int narg;
    710 	int maxcnt;
    711 {
    712 	char *np, *cp, *ep, *ap;
    713 	u_long oaddr = -1;
    714 	int len, cc;
    715 	char **argv;
    716 
    717 	/*
    718 	 * Check that there aren't an unreasonable number of agruments,
    719 	 * and that the address is in user space.
    720 	 */
    721 	if (narg > ARG_MAX || addr < kd->min_uva || addr >= kd->max_uva)
    722 		return (0);
    723 
    724 	if (kd->argv == 0) {
    725 		/*
    726 		 * Try to avoid reallocs.
    727 		 */
    728 		kd->argc = MAX(narg + 1, 32);
    729 		kd->argv = (char **)_kvm_malloc(kd, kd->argc *
    730 						sizeof(*kd->argv));
    731 		if (kd->argv == 0)
    732 			return (0);
    733 	} else if (narg + 1 > kd->argc) {
    734 		kd->argc = MAX(2 * kd->argc, narg + 1);
    735 		kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
    736 						sizeof(*kd->argv));
    737 		if (kd->argv == 0)
    738 			return (0);
    739 	}
    740 	if (kd->argspc == 0) {
    741 		kd->argspc = (char *)_kvm_malloc(kd, kd->nbpg);
    742 		if (kd->argspc == 0)
    743 			return (0);
    744 		kd->arglen = kd->nbpg;
    745 	}
    746 	if (kd->argbuf == 0) {
    747 		kd->argbuf = (char *)_kvm_malloc(kd, kd->nbpg);
    748 		if (kd->argbuf == 0)
    749 			return (0);
    750 	}
    751 	cc = sizeof(char *) * narg;
    752 	if (kvm_uread(kd, p, addr, (char *)kd->argv, cc) != cc)
    753 		return (0);
    754 	ap = np = kd->argspc;
    755 	argv = kd->argv;
    756 	len = 0;
    757 	/*
    758 	 * Loop over pages, filling in the argument vector.
    759 	 */
    760 	while (argv < kd->argv + narg && *argv != 0) {
    761 		addr = (u_long)*argv & ~(kd->nbpg - 1);
    762 		if (addr != oaddr) {
    763 			if (kvm_uread(kd, p, addr, kd->argbuf, kd->nbpg) !=
    764 			    kd->nbpg)
    765 				return (0);
    766 			oaddr = addr;
    767 		}
    768 		addr = (u_long)*argv & (kd->nbpg - 1);
    769 		cp = kd->argbuf + addr;
    770 		cc = kd->nbpg - addr;
    771 		if (maxcnt > 0 && cc > maxcnt - len)
    772 			cc = maxcnt - len;;
    773 		ep = memchr(cp, '\0', cc);
    774 		if (ep != 0)
    775 			cc = ep - cp + 1;
    776 		if (len + cc > kd->arglen) {
    777 			int off;
    778 			char **pp;
    779 			char *op = kd->argspc;
    780 
    781 			kd->arglen *= 2;
    782 			kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
    783 							  kd->arglen);
    784 			if (kd->argspc == 0)
    785 				return (0);
    786 			/*
    787 			 * Adjust argv pointers in case realloc moved
    788 			 * the string space.
    789 			 */
    790 			off = kd->argspc - op;
    791 			for (pp = kd->argv; pp < argv; pp++)
    792 				*pp += off;
    793 			ap += off;
    794 			np += off;
    795 		}
    796 		memcpy(np, cp, cc);
    797 		np += cc;
    798 		len += cc;
    799 		if (ep != 0) {
    800 			*argv++ = ap;
    801 			ap = np;
    802 		} else
    803 			*argv += cc;
    804 		if (maxcnt > 0 && len >= maxcnt) {
    805 			/*
    806 			 * We're stopping prematurely.  Terminate the
    807 			 * current string.
    808 			 */
    809 			if (ep == 0) {
    810 				*np = '\0';
    811 				*argv++ = ap;
    812 			}
    813 			break;
    814 		}
    815 	}
    816 	/* Make sure argv is terminated. */
    817 	*argv = 0;
    818 	return (kd->argv);
    819 }
    820 
    821 static void
    822 ps_str_a(p, addr, n)
    823 	struct ps_strings *p;
    824 	u_long *addr;
    825 	int *n;
    826 {
    827 	*addr = (u_long)p->ps_argvstr;
    828 	*n = p->ps_nargvstr;
    829 }
    830 
    831 static void
    832 ps_str_e(p, addr, n)
    833 	struct ps_strings *p;
    834 	u_long *addr;
    835 	int *n;
    836 {
    837 	*addr = (u_long)p->ps_envstr;
    838 	*n = p->ps_nenvstr;
    839 }
    840 
    841 /*
    842  * Determine if the proc indicated by p is still active.
    843  * This test is not 100% foolproof in theory, but chances of
    844  * being wrong are very low.
    845  */
    846 static int
    847 proc_verify(kd, kernp, p)
    848 	kvm_t *kd;
    849 	u_long kernp;
    850 	const struct proc *p;
    851 {
    852 	struct proc kernproc;
    853 
    854 	/*
    855 	 * Just read in the whole proc.  It's not that big relative
    856 	 * to the cost of the read system call.
    857 	 */
    858 	if (kvm_read(kd, kernp, (char *)&kernproc, sizeof(kernproc)) !=
    859 	    sizeof(kernproc))
    860 		return (0);
    861 	return (p->p_pid == kernproc.p_pid &&
    862 		(kernproc.p_stat != SZOMB || p->p_stat == SZOMB));
    863 }
    864 
    865 static char **
    866 kvm_doargv(kd, kp, nchr, info)
    867 	kvm_t *kd;
    868 	const struct kinfo_proc *kp;
    869 	int nchr;
    870 	void (*info)(struct ps_strings *, u_long *, int *);
    871 {
    872 	const struct proc *p = &kp->kp_proc;
    873 	char **ap;
    874 	u_long addr;
    875 	int cnt;
    876 	struct ps_strings arginfo;
    877 
    878 	/*
    879 	 * Pointers are stored at the top of the user stack.
    880 	 */
    881 	if (p->p_stat == SZOMB)
    882 		return (0);
    883 	cnt = kvm_uread(kd, p, kd->usrstack - sizeof(arginfo),
    884 	    (char *)&arginfo, sizeof(arginfo));
    885 	if (cnt != sizeof(arginfo))
    886 		return (0);
    887 
    888 	(*info)(&arginfo, &addr, &cnt);
    889 	if (cnt == 0)
    890 		return (0);
    891 	ap = kvm_argv(kd, p, addr, cnt, nchr);
    892 	/*
    893 	 * For live kernels, make sure this process didn't go away.
    894 	 */
    895 	if (ap != 0 && ISALIVE(kd) &&
    896 	    !proc_verify(kd, (u_long)kp->kp_eproc.e_paddr, p))
    897 		ap = 0;
    898 	return (ap);
    899 }
    900 
    901 /*
    902  * Get the command args.  This code is now machine independent.
    903  */
    904 char **
    905 kvm_getargv(kd, kp, nchr)
    906 	kvm_t *kd;
    907 	const struct kinfo_proc *kp;
    908 	int nchr;
    909 {
    910 	return (kvm_doargv(kd, kp, nchr, ps_str_a));
    911 }
    912 
    913 char **
    914 kvm_getenvv(kd, kp, nchr)
    915 	kvm_t *kd;
    916 	const struct kinfo_proc *kp;
    917 	int nchr;
    918 {
    919 	return (kvm_doargv(kd, kp, nchr, ps_str_e));
    920 }
    921 
    922 /*
    923  * Read from user space.  The user context is given by p.
    924  */
    925 ssize_t
    926 kvm_uread(kd, p, uva, buf, len)
    927 	kvm_t *kd;
    928 	const struct proc *p;
    929 	u_long uva;
    930 	char *buf;
    931 	size_t len;
    932 {
    933 	char *cp;
    934 
    935 	cp = buf;
    936 	while (len > 0) {
    937 		int cc;
    938 		char *dp;
    939 		u_long cnt;
    940 
    941 		dp = _kvm_uread(kd, p, uva, &cnt);
    942 		if (dp == 0) {
    943 			_kvm_err(kd, 0, "invalid address (%x)", uva);
    944 			return (0);
    945 		}
    946 		cc = MIN(cnt, len);
    947 		memcpy(cp, dp, cc);
    948 
    949 		cp += cc;
    950 		uva += cc;
    951 		len -= cc;
    952 	}
    953 	return (ssize_t)(cp - buf);
    954 }
    955