lib/libkvm/kvm_proc.c

   1 /*-
   2  * Copyright (c) 1989, 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software developed by the Computer Systems
   6  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
   7  * BG 91-66 and contributed to Berkeley.
   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  * $FreeBSD: src/lib/libkvm/kvm_proc.c,v 1.25.2.3 2002/08/24 07:27:46 kris Exp $
  38  * $DragonFly: src/lib/libkvm/kvm_proc.c,v 1.18 2008/06/05 18:06:30 swildner Exp $
  39  *
  40  * @(#)kvm_proc.c       8.3 (Berkeley) 9/23/93
  41  */
  42
  43 /*
  44  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
  45  * users of this code, so we've factored it out into a separate module.
  46  * Thus, we keep this grunge out of the other kvm applications (i.e.,
  47  * most other applications are interested only in open/close/read/nlist).
  48  */
  49
  50 #include <sys/user.h>   /* MUST BE FIRST */
  51 #include <sys/conf.h>
  52 #include <sys/param.h>
  53 #include <sys/proc.h>
  54 #include <sys/exec.h>
  55 #include <sys/stat.h>
  56 #include <sys/globaldata.h>
  57 #include <sys/ioctl.h>
  58 #include <sys/tty.h>
  59 #include <sys/file.h>
  60 #include <sys/jail.h>
  61 #include <stdio.h>
  62 #include <stdlib.h>
  63 #include <unistd.h>
  64 #include <nlist.h>
  65 #include <kvm.h>
  66
  67 #include <vm/vm.h>
  68 #include <vm/vm_param.h>
  69 #include <vm/swap_pager.h>
  70
  71 #include <sys/sysctl.h>
  72
  73 #include <limits.h>
  74 #include <memory.h>
  75 #include <paths.h>
  76
  77 #include "kvm_private.h"
  78
  79 #if used
  80 static char *
  81 kvm_readswap(kvm_t *kd, const struct proc *p, u_long va, u_long *cnt)
  82 {
  83 #if defined(__FreeBSD__) || defined(__DragonFly__)
  84         /* XXX Stubbed out, our vm system is differnet */
  85         _kvm_err(kd, kd->program, "kvm_readswap not implemented");
  86         return(0);
  87 #endif
  88 }
  89 #endif
  90
  91 #define KREAD(kd, addr, obj) \
  92         (kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
  93 #define KREADSTR(kd, addr) \
  94         kvm_readstr(kd, (u_long)addr, NULL, NULL)
  95
  96 static struct kinfo_proc *
  97 kinfo_resize_proc(kvm_t *kd, struct kinfo_proc *bp)
  98 {
  99         if (bp < kd->procend)
 100                 return bp;
 101
 102         size_t pos = bp - kd->procend;
 103         size_t size = kd->procend - kd->procbase;
 104
 105         if (size == 0)
 106                 size = 8;
 107         else
 108                 size *= 2;
 109         kd->procbase = _kvm_realloc(kd, kd->procbase, sizeof(*bp) * size);
 110         if (kd->procbase == NULL)
 111                 return NULL;
 112         kd->procend = kd->procbase + size;
 113         bp = kd->procbase + pos;
 114         return bp;
 115 }
 116
 117 /*
 118  * note: this function is also used by /usr/src/sys/kern/kern_kinfo.c as
 119  * compiled by userland.
 120  */
 121 dev_t
 122 dev2udev(cdev_t dev)
 123 {
 124         if (dev == NULL)
 125                 return NOUDEV;
 126         if ((dev->si_umajor & 0xffffff00) ||
 127             (dev->si_uminor & 0x0000ff00)) {
 128                 return NOUDEV;
 129         }
 130         return((dev->si_umajor << 8) | dev->si_uminor);
 131 }
 132
 133 /*
 134  * Helper routine which traverses the left hand side of a red-black sub-tree.
 135  */
 136 static uintptr_t
 137 kvm_lwptraverse(kvm_t *kd, struct lwp *lwp, uintptr_t lwppos)
 138 {
 139         for (;;) {
 140                 if (KREAD(kd, lwppos, lwp)) {
 141                         _kvm_err(kd, kd->program, "can't read lwp at %p",
 142                                  (void *)lwppos);
 143                         return ((uintptr_t)-1);
 144                 }
 145                 if (lwp->u.lwp_rbnode.rbe_left == NULL)
 146                         break;
 147                 lwppos = (uintptr_t)lwp->u.lwp_rbnode.rbe_left;
 148         }
 149         return(lwppos);
 150 }
 151
 152 /*
 153  * Iterate LWPs in a process.
 154  *
 155  * The first lwp in a red-black tree is a left-side traversal of the tree.
 156  */
 157 static uintptr_t
 158 kvm_firstlwp(kvm_t *kd, struct lwp *lwp, struct proc *proc)
 159 {
 160         return(kvm_lwptraverse(kd, lwp, (uintptr_t)proc->p_lwp_tree.rbh_root));
 161 }
 162
 163 /*
 164  * If the current element is the left side of the parent the next element
 165  * will be a left side traversal of the parent's right side.  If the parent
 166  * has no right side the next element will be the parent.
 167  *
 168  * If the current element is the right side of the parent the next element
 169  * is the parent.
 170  *
 171  * If the parent is NULL we are done.
 172  */
 173 static uintptr_t
 174 kvm_nextlwp(kvm_t *kd, uintptr_t lwppos, struct lwp *lwp, struct proc *proc)
 175 {
 176         uintptr_t nextpos;
 177
 178         nextpos = (uintptr_t)lwp->u.lwp_rbnode.rbe_parent;
 179         if (nextpos) {
 180                 if (KREAD(kd, nextpos, lwp)) {
 181                         _kvm_err(kd, kd->program, "can't read lwp at %p",
 182                                  (void *)lwppos);
 183                         return ((uintptr_t)-1);
 184                 }
 185                 if (lwppos == (uintptr_t)lwp->u.lwp_rbnode.rbe_left) {
 186                         /*
 187                          * If we had gone down the left side the next element
 188                          * is a left hand traversal of the parent's right
 189                          * side, or the parent itself if there is no right
 190                          * side.
 191                          */
 192                         lwppos = (uintptr_t)lwp->u.lwp_rbnode.rbe_right;
 193                         if (lwppos)
 194                                 nextpos = kvm_lwptraverse(kd, lwp, lwppos);
 195                 } else {
 196                         /*
 197                          * If we had gone down the right side the next
 198                          * element is the parent.
 199                          */
 200                         /* nextpos = nextpos */
 201                 }
 202         }
 203         return(nextpos);
 204 }
 205
 206 /*
 207  * Read proc's from memory file into buffer bp, which has space to hold
 208  * at most maxcnt procs.
 209  */
 210 static int
 211 kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
 212              struct kinfo_proc *bp)
 213 {
 214         struct pgrp pgrp;
 215         struct pgrp tpgrp;
 216         struct globaldata gdata;
 217         struct session sess;
 218         struct session tsess;
 219         struct tty tty;
 220         struct proc proc;
 221         struct ucred ucred;
 222         struct thread thread;
 223         struct proc pproc;
 224         struct cdev cdev;
 225         struct vmspace vmspace;
 226         struct prison prison;
 227         struct sigacts sigacts;
 228         struct lwp lwp;
 229         uintptr_t lwppos;
 230         int count;
 231         char *wmesg;
 232
 233         count = 0;
 234
 235         for (; p != NULL; p = proc.p_list.le_next) {
 236                 if (KREAD(kd, (u_long)p, &proc)) {
 237                         _kvm_err(kd, kd->program, "can't read proc at %x", p);
 238                         return (-1);
 239                 }
 240                 if (KREAD(kd, (u_long)proc.p_ucred, &ucred)) {
 241                         _kvm_err(kd, kd->program, "can't read ucred at %p",
 242                                  proc.p_ucred);
 243                         return (-1);
 244                 }
 245                 proc.p_ucred = &ucred;
 246
 247                 switch(what & ~KERN_PROC_FLAGMASK) {
 248
 249                 case KERN_PROC_PID:
 250                         if (proc.p_pid != (pid_t)arg)
 251                                 continue;
 252                         break;
 253
 254                 case KERN_PROC_UID:
 255                         if (ucred.cr_uid != (uid_t)arg)
 256                                 continue;
 257                         break;
 258
 259                 case KERN_PROC_RUID:
 260                         if (ucred.cr_ruid != (uid_t)arg)
 261                                 continue;
 262                         break;
 263                 }
 264
 265                 if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
 266                         _kvm_err(kd, kd->program, "can't read pgrp at %x",
 267                                  proc.p_pgrp);
 268                         return (-1);
 269                 }
 270                 proc.p_pgrp = &pgrp;
 271                 if (proc.p_pptr) {
 272                   if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
 273                         _kvm_err(kd, kd->program, "can't read pproc at %x",
 274                                  proc.p_pptr);
 275                         return (-1);
 276                   }
 277                   proc.p_pptr = &pproc;
 278                 }
 279
 280                 if (proc.p_sigacts) {
 281                         if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
 282                                 _kvm_err(kd, kd->program,
 283                                          "can't read sigacts at %p",
 284                                          proc.p_sigacts);
 285                                 return (-1);
 286                         }
 287                         proc.p_sigacts = &sigacts;
 288                 }
 289
 290                 if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
 291                         _kvm_err(kd, kd->program, "can't read session at %x",
 292                                 pgrp.pg_session);
 293                         return (-1);
 294                 }
 295                 pgrp.pg_session = &sess;
 296
 297                 if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
 298                         if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
 299                                 _kvm_err(kd, kd->program,
 300                                          "can't read tty at %x", sess.s_ttyp);
 301                                 return (-1);
 302                         }
 303                         sess.s_ttyp = &tty;
 304                         if (tty.t_dev && tty.t_dev != NULL) {
 305                                 if (KREAD(kd, (u_long)tty.t_dev, &cdev))
 306                                         tty.t_dev = NULL;
 307                                 else
 308                                         tty.t_dev = &cdev;
 309                         }
 310                         if (tty.t_pgrp != NULL) {
 311                                 if (KREAD(kd, (u_long)tty.t_pgrp, &tpgrp)) {
 312                                         _kvm_err(kd, kd->program,
 313                                                  "can't read tpgrp at %x",
 314                                                 tty.t_pgrp);
 315                                         return (-1);
 316                                 }
 317                                 tty.t_pgrp = &tpgrp;
 318                         }
 319                         if (tty.t_session != NULL) {
 320                                 if (KREAD(kd, (u_long)tty.t_session, &tsess)) {
 321                                         _kvm_err(kd, kd->program,
 322                                                  "can't read tsess at %p",
 323                                                 tty.t_session);
 324                                         return (-1);
 325                                 }
 326                                 tty.t_session = &tsess;
 327                         }
 328                 }
 329
 330                 if (KREAD(kd, (u_long)proc.p_vmspace, &vmspace)) {
 331                         _kvm_err(kd, kd->program, "can't read vmspace at %p",
 332                                  proc.p_vmspace);
 333                         return (-1);
 334                 }
 335                 proc.p_vmspace = &vmspace;
 336
 337                 if (ucred.cr_prison != NULL) {
 338                         if (KREAD(kd, (u_long)ucred.cr_prison, &prison)) {
 339                                 _kvm_err(kd, kd->program, "can't read prison at %p",
 340                                          ucred.cr_prison);
 341                                 return (-1);
 342                         }
 343                         ucred.cr_prison = &prison;
 344                 }
 345
 346                 switch (what & ~KERN_PROC_FLAGMASK) {
 347
 348                 case KERN_PROC_PGRP:
 349                         if (proc.p_pgrp->pg_id != (pid_t)arg)
 350                                 continue;
 351                         break;
 352
 353                 case KERN_PROC_TTY:
 354                         if ((proc.p_flag & P_CONTROLT) == 0 ||
 355                             dev2udev(proc.p_pgrp->pg_session->s_ttyp->t_dev)
 356                                         != (dev_t)arg)
 357                                 continue;
 358                         break;
 359                 }
 360
 361                 if ((bp = kinfo_resize_proc(kd, bp)) == NULL)
 362                         return (-1);
 363                 fill_kinfo_proc(&proc, bp);
 364                 bp->kp_paddr = (uintptr_t)p;
 365
 366                 lwppos = kvm_firstlwp(kd, &lwp, &proc);
 367                 if (lwppos == 0) {
 368                         bp++;           /* Just export the proc then */
 369                         count++;
 370                 }
 371                 while (lwppos && lwppos != (uintptr_t)-1) {
 372                         if (p != lwp.lwp_proc) {
 373                                 _kvm_err(kd, kd->program, "lwp has wrong parent");
 374                                 return (-1);
 375                         }
 376                         lwp.lwp_proc = &proc;
 377                         if (KREAD(kd, (u_long)lwp.lwp_thread, &thread)) {
 378                                 _kvm_err(kd, kd->program, "can't read thread at %x",
 379                                     lwp.lwp_thread);
 380                                 return (-1);
 381                         }
 382                         lwp.lwp_thread = &thread;
 383
 384                         if (thread.td_gd) {
 385                                 if (KREAD(kd, (u_long)thread.td_gd, &gdata)) {
 386                                         _kvm_err(kd, kd->program, "can't read"
 387                                                   " gd at %p",
 388                                                   thread.td_gd);
 389                                         return(-1);
 390                                 }
 391                                 thread.td_gd = &gdata;
 392                         }
 393                         if (thread.td_wmesg) {
 394                                 wmesg = (void *)KREADSTR(kd, thread.td_wmesg);
 395                                 if (wmesg == NULL) {
 396                                         _kvm_err(kd, kd->program, "can't read"
 397                                                   " wmesg %p",
 398                                                   thread.td_wmesg);
 399                                         return(-1);
 400                                 }
 401                                 thread.td_wmesg = wmesg;
 402                         } else {
 403                                 wmesg = NULL;
 404                         }
 405
 406                         if ((bp = kinfo_resize_proc(kd, bp)) == NULL)
 407                                 return (-1);
 408                         fill_kinfo_proc(&proc, bp);
 409                         fill_kinfo_lwp(&lwp, &bp->kp_lwp);
 410                         bp->kp_paddr = (uintptr_t)p;
 411                         bp++;
 412                         count++;
 413                         if (wmesg)
 414                                 free(wmesg);
 415                         if ((what & KERN_PROC_FLAG_LWP) == 0)
 416                                 break;
 417                         lwppos = kvm_nextlwp(kd, lwppos, &lwp, &proc);
 418                 }
 419                 if (lwppos == (uintptr_t)-1)
 420                         return(-1);
 421         }
 422         return (count);
 423 }
 424
 425 /*
 426  * Build proc info array by reading in proc list from a crash dump.
 427  * We reallocate kd->procbase as necessary.
 428  */
 429 static int
 430 kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
 431               u_long a_zombproc)
 432 {
 433         struct kinfo_proc *bp = kd->procbase;
 434         int acnt, zcnt;
 435         struct proc *p;
 436
 437         if (KREAD(kd, a_allproc, &p)) {
 438                 _kvm_err(kd, kd->program, "cannot read allproc");
 439                 return (-1);
 440         }
 441         acnt = kvm_proclist(kd, what, arg, p, bp);
 442         if (acnt < 0)
 443                 return (acnt);
 444
 445         if (KREAD(kd, a_zombproc, &p)) {
 446                 _kvm_err(kd, kd->program, "cannot read zombproc");
 447                 return (-1);
 448         }
 449         zcnt = kvm_proclist(kd, what, arg, p, bp + acnt);
 450         if (zcnt < 0)
 451                 zcnt = 0;
 452
 453         return (acnt + zcnt);
 454 }
 455
 456 struct kinfo_proc *
 457 kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
 458 {
 459         int mib[4], st, nprocs;
 460         int miblen = ((op & ~KERN_PROC_FLAGMASK) == KERN_PROC_ALL) ? 3 : 4;
 461         size_t size;
 462
 463         if (kd->procbase != 0) {
 464                 free((void *)kd->procbase);
 465                 /*
 466                  * Clear this pointer in case this call fails.  Otherwise,
 467                  * kvm_close() will free it again.
 468                  */
 469                 kd->procbase = 0;
 470         }
 471         if (ISALIVE(kd)) {
 472                 size = 0;
 473                 mib[0] = CTL_KERN;
 474                 mib[1] = KERN_PROC;
 475                 mib[2] = op;
 476                 mib[3] = arg;
 477                 st = sysctl(mib, miblen, NULL, &size, NULL, 0);
 478                 if (st == -1) {
 479                         _kvm_syserr(kd, kd->program, "kvm_getprocs");
 480                         return (0);
 481                 }
 482                 do {
 483                         size += size / 10;
 484                         kd->procbase = (struct kinfo_proc *)
 485                             _kvm_realloc(kd, kd->procbase, size);
 486                         if (kd->procbase == 0)
 487                                 return (0);
 488                         st = sysctl(mib, miblen, kd->procbase, &size, NULL, 0);
 489                 } while (st == -1 && errno == ENOMEM);
 490                 if (st == -1) {
 491                         _kvm_syserr(kd, kd->program, "kvm_getprocs");
 492                         return (0);
 493                 }
 494                 if (size % sizeof(struct kinfo_proc) != 0) {
 495                         _kvm_err(kd, kd->program,
 496                                 "proc size mismatch (%d total, %d chunks)",
 497                                 size, sizeof(struct kinfo_proc));
 498                         return (0);
 499                 }
 500                 nprocs = size / sizeof(struct kinfo_proc);
 501         } else {
 502                 struct nlist nl[4], *p;
 503
 504                 nl[0].n_name = "_nprocs";
 505                 nl[1].n_name = "_allproc";
 506                 nl[2].n_name = "_zombproc";
 507                 nl[3].n_name = 0;
 508
 509                 if (kvm_nlist(kd, nl) != 0) {
 510                         for (p = nl; p->n_type != 0; ++p)
 511                                 ;
 512                         _kvm_err(kd, kd->program,
 513                                  "%s: no such symbol", p->n_name);
 514                         return (0);
 515                 }
 516                 if (KREAD(kd, nl[0].n_value, &nprocs)) {
 517                         _kvm_err(kd, kd->program, "can't read nprocs");
 518                         return (0);
 519                 }
 520                 nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
 521                                       nl[2].n_value);
 522 #ifdef notdef
 523                 size = nprocs * sizeof(struct kinfo_proc);
 524                 (void)realloc(kd->procbase, size);
 525 #endif
 526         }
 527         *cnt = nprocs;
 528         return (kd->procbase);
 529 }
 530
 531 void
 532 _kvm_freeprocs(kvm_t *kd)
 533 {
 534         if (kd->procbase) {
 535                 free(kd->procbase);
 536                 kd->procbase = 0;
 537         }
 538 }
 539
 540 void *
 541 _kvm_realloc(kvm_t *kd, void *p, size_t n)
 542 {
 543         void *np = (void *)realloc(p, n);
 544
 545         if (np == 0) {
 546                 free(p);
 547                 _kvm_err(kd, kd->program, "out of memory");
 548         }
 549         return (np);
 550 }
 551
 552 #ifndef MAX
 553 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 554 #endif
 555
 556 /*
 557  * Read in an argument vector from the user address space of process pid.
 558  * addr if the user-space base address of narg null-terminated contiguous
 559  * strings.  This is used to read in both the command arguments and
 560  * environment strings.  Read at most maxcnt characters of strings.
 561  */
 562 static char **
 563 kvm_argv(kvm_t *kd, pid_t pid, u_long addr, int narg, int maxcnt)
 564 {
 565         char *np, *cp, *ep, *ap;
 566         u_long oaddr = -1;
 567         int len, cc;
 568         char **argv;
 569
 570         /*
 571          * Check that there aren't an unreasonable number of agruments,
 572          * and that the address is in user space.
 573          */
 574         if (narg > 512 ||
 575             addr < VM_MIN_USER_ADDRESS || addr >= VM_MAX_USER_ADDRESS) {
 576                 return (0);
 577         }
 578
 579         /*
 580          * kd->argv : work space for fetching the strings from the target
 581          *            process's space, and is converted for returning to caller
 582          */
 583         if (kd->argv == 0) {
 584                 /*
 585                  * Try to avoid reallocs.
 586                  */
 587                 kd->argc = MAX(narg + 1, 32);
 588                 kd->argv = (char **)_kvm_malloc(kd, kd->argc *
 589                                                 sizeof(*kd->argv));
 590                 if (kd->argv == 0)
 591                         return (0);
 592         } else if (narg + 1 > kd->argc) {
 593                 kd->argc = MAX(2 * kd->argc, narg + 1);
 594                 kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
 595                                                 sizeof(*kd->argv));
 596                 if (kd->argv == 0)
 597                         return (0);
 598         }
 599         /*
 600          * kd->argspc : returned to user, this is where the kd->argv
 601          *              arrays are left pointing to the collected strings.
 602          */
 603         if (kd->argspc == 0) {
 604                 kd->argspc = (char *)_kvm_malloc(kd, PAGE_SIZE);
 605                 if (kd->argspc == 0)
 606                         return (0);
 607                 kd->arglen = PAGE_SIZE;
 608         }
 609         /*
 610          * kd->argbuf : used to pull in pages from the target process.
 611          *              the strings are copied out of here.
 612          */
 613         if (kd->argbuf == 0) {
 614                 kd->argbuf = (char *)_kvm_malloc(kd, PAGE_SIZE);
 615                 if (kd->argbuf == 0)
 616                         return (0);
 617         }
 618
 619         /* Pull in the target process'es argv vector */
 620         cc = sizeof(char *) * narg;
 621         if (kvm_uread(kd, pid, addr, (char *)kd->argv, cc) != cc)
 622                 return (0);
 623         /*
 624          * ap : saved start address of string we're working on in kd->argspc
 625          * np : pointer to next place to write in kd->argspc
 626          * len: length of data in kd->argspc
 627          * argv: pointer to the argv vector that we are hunting around the
 628          *       target process space for, and converting to addresses in
 629          *       our address space (kd->argspc).
 630          */
 631         ap = np = kd->argspc;
 632         argv = kd->argv;
 633         len = 0;
 634         /*
 635          * Loop over pages, filling in the argument vector.
 636          * Note that the argv strings could be pointing *anywhere* in
 637          * the user address space and are no longer contiguous.
 638          * Note that *argv is modified when we are going to fetch a string
 639          * that crosses a page boundary.  We copy the next part of the string
 640          * into to "np" and eventually convert the pointer.
 641          */
 642         while (argv < kd->argv + narg && *argv != 0) {
 643
 644                 /* get the address that the current argv string is on */
 645                 addr = (u_long)*argv & ~(PAGE_SIZE - 1);
 646
 647                 /* is it the same page as the last one? */
 648                 if (addr != oaddr) {
 649                         if (kvm_uread(kd, pid, addr, kd->argbuf, PAGE_SIZE) !=
 650                             PAGE_SIZE)
 651                                 return (0);
 652                         oaddr = addr;
 653                 }
 654
 655                 /* offset within the page... kd->argbuf */
 656                 addr = (u_long)*argv & (PAGE_SIZE - 1);
 657
 658                 /* cp = start of string, cc = count of chars in this chunk */
 659                 cp = kd->argbuf + addr;
 660                 cc = PAGE_SIZE - addr;
 661
 662                 /* dont get more than asked for by user process */
 663                 if (maxcnt > 0 && cc > maxcnt - len)
 664                         cc = maxcnt - len;
 665
 666                 /* pointer to end of string if we found it in this page */
 667                 ep = memchr(cp, '\0', cc);
 668                 if (ep != 0)
 669                         cc = ep - cp + 1;
 670                 /*
 671                  * at this point, cc is the count of the chars that we are
 672                  * going to retrieve this time. we may or may not have found
 673                  * the end of it.  (ep points to the null if the end is known)
 674                  */
 675
 676                 /* will we exceed the malloc/realloced buffer? */
 677                 if (len + cc > kd->arglen) {
 678                         int off;
 679                         char **pp;
 680                         char *op = kd->argspc;
 681
 682                         kd->arglen *= 2;
 683                         kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
 684                                                           kd->arglen);
 685                         if (kd->argspc == 0)
 686                                 return (0);
 687                         /*
 688                          * Adjust argv pointers in case realloc moved
 689                          * the string space.
 690                          */
 691                         off = kd->argspc - op;
 692                         for (pp = kd->argv; pp < argv; pp++)
 693                                 *pp += off;
 694                         ap += off;
 695                         np += off;
 696                 }
 697                 /* np = where to put the next part of the string in kd->argspc*/
 698                 /* np is kinda redundant.. could use "kd->argspc + len" */
 699                 memcpy(np, cp, cc);
 700                 np += cc;       /* inc counters */
 701                 len += cc;
 702
 703                 /*
 704                  * if end of string found, set the *argv pointer to the
 705                  * saved beginning of string, and advance. argv points to
 706                  * somewhere in kd->argv..  This is initially relative
 707                  * to the target process, but when we close it off, we set
 708                  * it to point in our address space.
 709                  */
 710                 if (ep != 0) {
 711                         *argv++ = ap;
 712                         ap = np;
 713                 } else {
 714                         /* update the address relative to the target process */
 715                         *argv += cc;
 716                 }
 717
 718                 if (maxcnt > 0 && len >= maxcnt) {
 719                         /*
 720                          * We're stopping prematurely.  Terminate the
 721                          * current string.
 722                          */
 723                         if (ep == 0) {
 724                                 *np = '\0';
 725                                 *argv++ = ap;
 726                         }
 727                         break;
 728                 }
 729         }
 730         /* Make sure argv is terminated. */
 731         *argv = 0;
 732         return (kd->argv);
 733 }
 734
 735 static void
 736 ps_str_a(struct ps_strings *p, u_long *addr, int *n)
 737 {
 738         *addr = (u_long)p->ps_argvstr;
 739         *n = p->ps_nargvstr;
 740 }
 741
 742 static void
 743 ps_str_e(struct ps_strings *p, u_long *addr, int *n)
 744 {
 745         *addr = (u_long)p->ps_envstr;
 746         *n = p->ps_nenvstr;
 747 }
 748
 749 /*
 750  * Determine if the proc indicated by p is still active.
 751  * This test is not 100% foolproof in theory, but chances of
 752  * being wrong are very low.
 753  */
 754 static int
 755 proc_verify(kvm_t *kd, const struct kinfo_proc *p)
 756 {
 757         struct kinfo_proc kp;
 758         int mib[4];
 759         size_t len;
 760         int error;
 761
 762         mib[0] = CTL_KERN;
 763         mib[1] = KERN_PROC;
 764         mib[2] = KERN_PROC_PID;
 765         mib[3] = p->kp_pid;
 766
 767         len = sizeof(kp);
 768         error = sysctl(mib, 4, &kp, &len, NULL, 0);
 769         if (error)
 770                 return (0);
 771
 772         error = (p->kp_pid == kp.kp_pid &&
 773             (kp.kp_stat != SZOMB || p->kp_stat == SZOMB));
 774         return (error);
 775 }
 776
 777 static char **
 778 kvm_doargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr,
 779            void (*info)(struct ps_strings *, u_long *, int *))
 780 {
 781         char **ap;
 782         u_long addr;
 783         int cnt;
 784         static struct ps_strings arginfo;
 785         static u_long ps_strings;
 786         size_t len;
 787
 788         if (ps_strings == 0) {
 789                 len = sizeof(ps_strings);
 790                 if (sysctlbyname("kern.ps_strings", &ps_strings, &len, NULL,
 791                     0) == -1)
 792                         ps_strings = PS_STRINGS;
 793         }
 794
 795         /*
 796          * Pointers are stored at the top of the user stack.
 797          */
 798         if (kp->kp_stat == SZOMB ||
 799             kvm_uread(kd, kp->kp_pid, ps_strings, (char *)&arginfo,
 800                       sizeof(arginfo)) != sizeof(arginfo))
 801                 return (0);
 802
 803         (*info)(&arginfo, &addr, &cnt);
 804         if (cnt == 0)
 805                 return (0);
 806         ap = kvm_argv(kd, kp->kp_pid, addr, cnt, nchr);
 807         /*
 808          * For live kernels, make sure this process didn't go away.
 809          */
 810         if (ap != 0 && ISALIVE(kd) &&
 811             !proc_verify(kd, kp))
 812                 ap = 0;
 813         return (ap);
 814 }
 815
 816 /*
 817  * Get the command args.  This code is now machine independent.
 818  */
 819 char **
 820 kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
 821 {
 822         int oid[4];
 823         int i;
 824         size_t bufsz;
 825         static unsigned long buflen;
 826         static char *buf, *p;
 827         static char **bufp;
 828         static int argc;
 829
 830         if (!ISALIVE(kd)) {
 831                 _kvm_err(kd, kd->program,
 832                     "cannot read user space from dead kernel");
 833                 return (0);
 834         }
 835
 836         if (!buflen) {
 837                 bufsz = sizeof(buflen);
 838                 i = sysctlbyname("kern.ps_arg_cache_limit",
 839                     &buflen, &bufsz, NULL, 0);
 840                 if (i == -1) {
 841                         buflen = 0;
 842                 } else {
 843                         buf = malloc(buflen);
 844                         if (buf == NULL)
 845                                 buflen = 0;
 846                         argc = 32;
 847                         bufp = malloc(sizeof(char *) * argc);
 848                 }
 849         }
 850         if (buf != NULL) {
 851                 oid[0] = CTL_KERN;
 852                 oid[1] = KERN_PROC;
 853                 oid[2] = KERN_PROC_ARGS;
 854                 oid[3] = kp->kp_pid;
 855                 bufsz = buflen;
 856                 i = sysctl(oid, 4, buf, &bufsz, 0, 0);
 857                 if (i == 0 && bufsz > 0) {
 858                         i = 0;
 859                         p = buf;
 860                         do {
 861                                 bufp[i++] = p;
 862                                 p += strlen(p) + 1;
 863                                 if (i >= argc) {
 864                                         argc += argc;
 865                                         bufp = realloc(bufp,
 866                                             sizeof(char *) * argc);
 867                                 }
 868                         } while (p < buf + bufsz);
 869                         bufp[i++] = 0;
 870                         return (bufp);
 871                 }
 872         }
 873         if (kp->kp_flags & P_SYSTEM)
 874                 return (NULL);
 875         return (kvm_doargv(kd, kp, nchr, ps_str_a));
 876 }
 877
 878 char **
 879 kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
 880 {
 881         return (kvm_doargv(kd, kp, nchr, ps_str_e));
 882 }
 883
 884 /*
 885  * Read from user space.  The user context is given by pid.
 886  */
 887 ssize_t
 888 kvm_uread(kvm_t *kd, pid_t pid, u_long uva, char *buf, size_t len)
 889 {
 890         char *cp;
 891         char procfile[MAXPATHLEN];
 892         ssize_t amount;
 893         int fd;
 894
 895         if (!ISALIVE(kd)) {
 896                 _kvm_err(kd, kd->program,
 897                     "cannot read user space from dead kernel");
 898                 return (0);
 899         }
 900
 901         sprintf(procfile, "/proc/%d/mem", pid);
 902         fd = open(procfile, O_RDONLY, 0);
 903         if (fd < 0) {
 904                 _kvm_err(kd, kd->program, "cannot open %s", procfile);
 905                 close(fd);
 906                 return (0);
 907         }
 908
 909         cp = buf;
 910         while (len > 0) {
 911                 errno = 0;
 912                 if (lseek(fd, (off_t)uva, 0) == -1 && errno != 0) {
 913                         _kvm_err(kd, kd->program, "invalid address (%x) in %s",
 914                             uva, procfile);
 915                         break;
 916                 }
 917                 amount = read(fd, cp, len);
 918                 if (amount < 0) {
 919                         _kvm_syserr(kd, kd->program, "error reading %s",
 920                             procfile);
 921                         break;
 922                 }
 923                 if (amount == 0) {
 924                         _kvm_err(kd, kd->program, "EOF reading %s", procfile);
 925                         break;
 926                 }
 927                 cp += amount;
 928                 uva += amount;
 929                 len -= amount;
 930         }
 931
 932         close(fd);
 933         return ((ssize_t)(cp - buf));
 934 }