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. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/lib/libkvm/kvm_proc.c,v 1.25.2.3 2002/08/24 07:27:46 kris Exp $
  34  *
  35  * @(#)kvm_proc.c       8.3 (Berkeley) 9/23/93
  36  */
  37
  38 /*
  39  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
  40  * users of this code, so we've factored it out into a separate module.
  41  * Thus, we keep this grunge out of the other kvm applications (i.e.,
  42  * most other applications are interested only in open/close/read/nlist).
  43  */
  44
  45 #include <sys/user.h>   /* MUST BE FIRST */
  46 #include <sys/conf.h>
  47 #include <sys/param.h>
  48 #include <sys/proc.h>
  49 #include <sys/exec.h>
  50 #include <sys/stat.h>
  51 #include <sys/globaldata.h>
  52 #include <sys/ioctl.h>
  53 #include <sys/tty.h>
  54 #include <sys/file.h>
  55 #include <sys/jail.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <stddef.h>
  59 #include <unistd.h>
  60 #include <nlist.h>
  61
  62 #include <vm/vm.h>
  63 #include <vm/vm_param.h>
  64 #include <vm/swap_pager.h>
  65
  66 #include <sys/sysctl.h>
  67
  68 #include <limits.h>
  69 #include <memory.h>
  70 #include <paths.h>
  71
  72 #include "kvm.h"
  73 #include "kvm_private.h"
  74
  75 dev_t   dev2udev(cdev_t dev);
  76
  77 #define KREAD(kd, addr, obj) \
  78         (kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
  79 #define KREADSTR(kd, addr) \
  80         kvm_readstr(kd, (u_long)addr, NULL, NULL)
  81
  82 static struct kinfo_proc *
  83 kinfo_resize_proc(kvm_t *kd, struct kinfo_proc *bp)
  84 {
  85         if (bp < kd->procend)
  86                 return bp;
  87
  88         size_t pos = bp - kd->procend;
  89         size_t size = kd->procend - kd->procbase;
  90
  91         if (size == 0)
  92                 size = 8;
  93         else
  94                 size *= 2;
  95         kd->procbase = _kvm_realloc(kd, kd->procbase, sizeof(*bp) * size);
  96         if (kd->procbase == NULL)
  97                 return NULL;
  98         kd->procend = kd->procbase + size;
  99         bp = kd->procbase + pos;
 100         return bp;
 101 }
 102
 103 /*
 104  * note: this function is also used by /usr/src/sys/kern/kern_kinfo.c as
 105  * compiled by userland.
 106  */
 107 dev_t
 108 dev2udev(cdev_t dev)
 109 {
 110         if (dev == NULL)
 111                 return NOUDEV;
 112         if ((dev->si_umajor & 0xffffff00) ||
 113             (dev->si_uminor & 0x0000ff00)) {
 114                 return NOUDEV;
 115         }
 116         return((dev->si_umajor << 8) | dev->si_uminor);
 117 }
 118
 119 /*
 120  * Helper routine which traverses the left hand side of a red-black sub-tree.
 121  */
 122 static uintptr_t
 123 kvm_lwptraverse(kvm_t *kd, struct lwp *lwp, uintptr_t lwppos)
 124 {
 125         for (;;) {
 126                 if (KREAD(kd, lwppos, lwp)) {
 127                         _kvm_err(kd, kd->program, "can't read lwp at %p",
 128                                  (void *)lwppos);
 129                         return ((uintptr_t)-1);
 130                 }
 131                 if (lwp->u.lwp_rbnode.rbe_left == NULL)
 132                         break;
 133                 lwppos = (uintptr_t)lwp->u.lwp_rbnode.rbe_left;
 134         }
 135         return(lwppos);
 136 }
 137
 138 /*
 139  * Iterate LWPs in a process.
 140  *
 141  * The first lwp in a red-black tree is a left-side traversal of the tree.
 142  */
 143 static uintptr_t
 144 kvm_firstlwp(kvm_t *kd, struct lwp *lwp, struct proc *proc)
 145 {
 146         return(kvm_lwptraverse(kd, lwp, (uintptr_t)proc->p_lwp_tree.rbh_root));
 147 }
 148
 149 /*
 150  * If the current element is the left side of the parent the next element
 151  * will be a left side traversal of the parent's right side.  If the parent
 152  * has no right side the next element will be the parent.
 153  *
 154  * If the current element is the right side of the parent the next element
 155  * is the parent.
 156  *
 157  * If the parent is NULL we are done.
 158  */
 159 static uintptr_t
 160 kvm_nextlwp(kvm_t *kd, uintptr_t lwppos, struct lwp *lwp)
 161 {
 162         uintptr_t nextpos;
 163
 164         nextpos = (uintptr_t)lwp->u.lwp_rbnode.rbe_parent;
 165         if (nextpos) {
 166                 if (KREAD(kd, nextpos, lwp)) {
 167                         _kvm_err(kd, kd->program, "can't read lwp at %p",
 168                                  (void *)lwppos);
 169                         return ((uintptr_t)-1);
 170                 }
 171                 if (lwppos == (uintptr_t)lwp->u.lwp_rbnode.rbe_left) {
 172                         /*
 173                          * If we had gone down the left side the next element
 174                          * is a left hand traversal of the parent's right
 175                          * side, or the parent itself if there is no right
 176                          * side.
 177                          */
 178                         lwppos = (uintptr_t)lwp->u.lwp_rbnode.rbe_right;
 179                         if (lwppos)
 180                                 nextpos = kvm_lwptraverse(kd, lwp, lwppos);
 181                 } else {
 182                         /*
 183                          * If we had gone down the right side the next
 184                          * element is the parent.
 185                          */
 186                         /* nextpos = nextpos */
 187                 }
 188         }
 189         return(nextpos);
 190 }
 191
 192 /*
 193  * Read proc's from memory file into buffer bp, which has space to hold
 194  * at most maxcnt procs.
 195  */
 196 static int
 197 kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
 198              struct kinfo_proc *bp)
 199 {
 200         struct pgrp pgrp;
 201         struct pgrp tpgrp;
 202         struct globaldata gdata;
 203         struct session sess;
 204         struct session tsess;
 205         struct tty tty;
 206         struct proc proc;
 207         struct ucred ucred;
 208         struct thread thread;
 209         struct proc pproc;
 210         struct cdev cdev;
 211         struct vmspace vmspace;
 212         struct prison prison;
 213         struct sigacts sigacts;
 214         struct lwp lwp;
 215         uintptr_t lwppos;
 216         int count;
 217         char *wmesg;
 218
 219         count = 0;
 220
 221         for (; p != NULL; p = proc.p_list.le_next) {
 222                 if (KREAD(kd, (u_long)p, &proc)) {
 223                         _kvm_err(kd, kd->program, "can't read proc at %p", p);
 224                         return (-1);
 225                 }
 226                 if (KREAD(kd, (u_long)proc.p_ucred, &ucred)) {
 227                         _kvm_err(kd, kd->program, "can't read ucred at %p",
 228                                  proc.p_ucred);
 229                         return (-1);
 230                 }
 231                 proc.p_ucred = &ucred;
 232
 233                 switch(what & ~KERN_PROC_FLAGMASK) {
 234
 235                 case KERN_PROC_PID:
 236                         if (proc.p_pid != (pid_t)arg)
 237                                 continue;
 238                         break;
 239
 240                 case KERN_PROC_UID:
 241                         if (ucred.cr_uid != (uid_t)arg)
 242                                 continue;
 243                         break;
 244
 245                 case KERN_PROC_RUID:
 246                         if (ucred.cr_ruid != (uid_t)arg)
 247                                 continue;
 248                         break;
 249                 }
 250
 251                 if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
 252                         _kvm_err(kd, kd->program, "can't read pgrp at %p",
 253                                  proc.p_pgrp);
 254                         return (-1);
 255                 }
 256                 proc.p_pgrp = &pgrp;
 257                 if (proc.p_pptr) {
 258                   if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
 259                         _kvm_err(kd, kd->program, "can't read pproc at %p",
 260                                  proc.p_pptr);
 261                         return (-1);
 262                   }
 263                   proc.p_pptr = &pproc;
 264                 }
 265
 266                 if (proc.p_sigacts) {
 267                         if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
 268                                 _kvm_err(kd, kd->program,
 269                                          "can't read sigacts at %p",
 270                                          proc.p_sigacts);
 271                                 return (-1);
 272                         }
 273                         proc.p_sigacts = &sigacts;
 274                 }
 275
 276                 if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
 277                         _kvm_err(kd, kd->program, "can't read session at %p",
 278                                 pgrp.pg_session);
 279                         return (-1);
 280                 }
 281                 pgrp.pg_session = &sess;
 282
 283                 if ((proc.p_flags & P_CONTROLT) && sess.s_ttyp != NULL) {
 284                         if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
 285                                 _kvm_err(kd, kd->program,
 286                                          "can't read tty at %p", sess.s_ttyp);
 287                                 return (-1);
 288                         }
 289                         sess.s_ttyp = &tty;
 290                         if (tty.t_dev != NULL) {
 291                                 if (KREAD(kd, (u_long)tty.t_dev, &cdev))
 292                                         tty.t_dev = NULL;
 293                                 else
 294                                         tty.t_dev = &cdev;
 295                         }
 296                         if (tty.t_pgrp != NULL) {
 297                                 if (KREAD(kd, (u_long)tty.t_pgrp, &tpgrp)) {
 298                                         _kvm_err(kd, kd->program,
 299                                                  "can't read tpgrp at %p",
 300                                                 tty.t_pgrp);
 301                                         return (-1);
 302                                 }
 303                                 tty.t_pgrp = &tpgrp;
 304                         }
 305                         if (tty.t_session != NULL) {
 306                                 if (KREAD(kd, (u_long)tty.t_session, &tsess)) {
 307                                         _kvm_err(kd, kd->program,
 308                                                  "can't read tsess at %p",
 309                                                 tty.t_session);
 310                                         return (-1);
 311                                 }
 312                                 tty.t_session = &tsess;
 313                         }
 314                 }
 315
 316                 if (KREAD(kd, (u_long)proc.p_vmspace, &vmspace)) {
 317                         _kvm_err(kd, kd->program, "can't read vmspace at %p",
 318                                  proc.p_vmspace);
 319                         return (-1);
 320                 }
 321                 proc.p_vmspace = &vmspace;
 322
 323                 if (ucred.cr_prison != NULL) {
 324                         if (KREAD(kd, (u_long)ucred.cr_prison, &prison)) {
 325                                 _kvm_err(kd, kd->program, "can't read prison at %p",
 326                                          ucred.cr_prison);
 327                                 return (-1);
 328                         }
 329                         ucred.cr_prison = &prison;
 330                 }
 331
 332                 switch (what & ~KERN_PROC_FLAGMASK) {
 333
 334                 case KERN_PROC_PGRP:
 335                         if (proc.p_pgrp->pg_id != (pid_t)arg)
 336                                 continue;
 337                         break;
 338
 339                 case KERN_PROC_TTY:
 340                         if ((proc.p_flags & P_CONTROLT) == 0 ||
 341                             dev2udev(proc.p_pgrp->pg_session->s_ttyp->t_dev)
 342                                         != (dev_t)arg)
 343                                 continue;
 344                         break;
 345                 }
 346
 347                 if ((bp = kinfo_resize_proc(kd, bp)) == NULL)
 348                         return (-1);
 349                 fill_kinfo_proc(&proc, bp);
 350                 bp->kp_paddr = (uintptr_t)p;
 351
 352                 lwppos = kvm_firstlwp(kd, &lwp, &proc);
 353                 if (lwppos == 0) {
 354                         bp++;           /* Just export the proc then */
 355                         count++;
 356                 }
 357                 while (lwppos && lwppos != (uintptr_t)-1) {
 358                         if (p != lwp.lwp_proc) {
 359                                 _kvm_err(kd, kd->program, "lwp has wrong parent");
 360                                 return (-1);
 361                         }
 362                         lwp.lwp_proc = &proc;
 363                         if (KREAD(kd, (u_long)lwp.lwp_thread, &thread)) {
 364                                 _kvm_err(kd, kd->program, "can't read thread at %p",
 365                                     lwp.lwp_thread);
 366                                 return (-1);
 367                         }
 368                         lwp.lwp_thread = &thread;
 369
 370                         if (thread.td_gd) {
 371                                 if (KREAD(kd, (u_long)thread.td_gd, &gdata)) {
 372                                         _kvm_err(kd, kd->program, "can't read"
 373                                                   " gd at %p",
 374                                                   thread.td_gd);
 375                                         return(-1);
 376                                 }
 377                                 thread.td_gd = &gdata;
 378                         }
 379                         if (thread.td_wmesg) {
 380                                 wmesg = (void *)KREADSTR(kd, thread.td_wmesg);
 381                                 if (wmesg == NULL) {
 382                                         _kvm_err(kd, kd->program, "can't read"
 383                                                   " wmesg %p",
 384                                                   thread.td_wmesg);
 385                                         return(-1);
 386                                 }
 387                                 thread.td_wmesg = wmesg;
 388                         } else {
 389                                 wmesg = NULL;
 390                         }
 391
 392                         if ((bp = kinfo_resize_proc(kd, bp)) == NULL)
 393                                 return (-1);
 394                         fill_kinfo_proc(&proc, bp);
 395                         fill_kinfo_lwp(&lwp, &bp->kp_lwp);
 396                         bp->kp_paddr = (uintptr_t)p;
 397                         bp++;
 398                         count++;
 399                         if (wmesg)
 400                                 free(wmesg);
 401                         if ((what & KERN_PROC_FLAG_LWP) == 0)
 402                                 break;
 403                         lwppos = kvm_nextlwp(kd, lwppos, &lwp);
 404                 }
 405                 if (lwppos == (uintptr_t)-1)
 406                         return(-1);
 407         }
 408         return (count);
 409 }
 410
 411 /*
 412  * Build proc info array by reading in proc list from a crash dump.
 413  * We reallocate kd->procbase as necessary.
 414  */
 415 static int
 416 kvm_deadprocs(kvm_t *kd, int what, int arg, int allproc_hsize)
 417 {
 418         struct kinfo_proc *bp;
 419         struct proc *p;
 420         struct proclist **pl;
 421         int cnt, partcnt, n;
 422         u_long nextoff;
 423         u_long a_allproc;
 424
 425         cnt = partcnt = 0;
 426         nextoff = 0;
 427
 428         /*
 429          * Dynamically allocate space for all the elements of the
 430          * allprocs array and KREAD() them.
 431          */
 432         pl = _kvm_malloc(kd, allproc_hsize * sizeof(struct proclist *));
 433         for (n = 0; n < allproc_hsize; n++) {
 434                 pl[n] = _kvm_malloc(kd, sizeof(struct proclist));
 435                 a_allproc = sizeof(struct procglob) * n +
 436                             offsetof(struct procglob, allproc);
 437                 nextoff = a_allproc;
 438                 if (KREAD(kd, (u_long)nextoff, pl[n])) {
 439                         _kvm_err(kd, kd->program, "can't read proclist at 0x%lx",
 440                                 a_allproc);
 441                         return (-1);
 442                 }
 443
 444                 /* Ignore empty proclists */
 445                 if (LIST_EMPTY(pl[n]))
 446                         continue;
 447
 448                 bp = kd->procbase + cnt;
 449                 p = pl[n]->lh_first;
 450                 partcnt = kvm_proclist(kd, what, arg, p, bp);
 451                 if (partcnt < 0) {
 452                         free(pl[n]);
 453                         return (partcnt);
 454                 }
 455
 456                 cnt += partcnt;
 457                 free(pl[n]);
 458         }
 459
 460         return (cnt);
 461 }
 462
 463 struct kinfo_proc *
 464 kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
 465 {
 466         int mib[4], st, nprocs, allproc_hsize;
 467         int miblen = ((op & ~KERN_PROC_FLAGMASK) == KERN_PROC_ALL) ? 3 : 4;
 468         size_t size;
 469
 470         if (kd->procbase != 0) {
 471                 free((void *)kd->procbase);
 472                 /*
 473                  * Clear this pointer in case this call fails.  Otherwise,
 474                  * kvm_close() will free it again.
 475                  */
 476                 kd->procbase = 0;
 477         }
 478         if (kvm_ishost(kd)) {
 479                 size = 0;
 480                 mib[0] = CTL_KERN;
 481                 mib[1] = KERN_PROC;
 482                 mib[2] = op;
 483                 mib[3] = arg;
 484                 st = sysctl(mib, miblen, NULL, &size, NULL, 0);
 485                 if (st == -1) {
 486                         _kvm_syserr(kd, kd->program, "kvm_getprocs");
 487                         return (0);
 488                 }
 489                 do {
 490                         size += size / 10;
 491                         kd->procbase = (struct kinfo_proc *)
 492                             _kvm_realloc(kd, kd->procbase, size);
 493                         if (kd->procbase == 0)
 494                                 return (0);
 495                         st = sysctl(mib, miblen, kd->procbase, &size, NULL, 0);
 496                 } while (st == -1 && errno == ENOMEM);
 497                 if (st == -1) {
 498                         _kvm_syserr(kd, kd->program, "kvm_getprocs");
 499                         return (0);
 500                 }
 501                 if (size % sizeof(struct kinfo_proc) != 0) {
 502                         _kvm_err(kd, kd->program,
 503                                 "proc size mismatch (%zd total, %zd chunks)",
 504                                 size, sizeof(struct kinfo_proc));
 505                         return (0);
 506                 }
 507                 nprocs = size / sizeof(struct kinfo_proc);
 508         } else {
 509                 struct nlist nl[4], *p;
 510
 511                 nl[0].n_name = "_nprocs";
 512                 nl[1].n_name = "_procglob";
 513                 nl[2].n_name = "_allproc_hsize";
 514                 nl[3].n_name = 0;
 515
 516                 if (kvm_nlist(kd, nl) != 0) {
 517                         for (p = nl; p->n_type != 0; ++p)
 518                                 ;
 519                         _kvm_err(kd, kd->program,
 520                                  "%s: no such symbol", p->n_name);
 521                         return (0);
 522                 }
 523                 if (KREAD(kd, nl[0].n_value, &nprocs)) {
 524                         _kvm_err(kd, kd->program, "can't read nprocs");
 525                         return (0);
 526                 }
 527                 if (KREAD(kd, nl[2].n_value, &allproc_hsize)) {
 528                         _kvm_err(kd, kd->program, "can't read allproc_hsize");
 529                         return (0);
 530                 }
 531                 nprocs = kvm_deadprocs(kd, op, arg, allproc_hsize);
 532 #ifdef notdef
 533                 size = nprocs * sizeof(struct kinfo_proc);
 534                 (void)realloc(kd->procbase, size);
 535 #endif
 536         }
 537         *cnt = nprocs;
 538         return (kd->procbase);
 539 }
 540
 541 void
 542 _kvm_freeprocs(kvm_t *kd)
 543 {
 544         if (kd->procbase) {
 545                 free(kd->procbase);
 546                 kd->procbase = 0;
 547         }
 548 }
 549
 550 void *
 551 _kvm_realloc(kvm_t *kd, void *p, size_t n)
 552 {
 553         void *np = (void *)realloc(p, n);
 554
 555         if (np == NULL) {
 556                 free(p);
 557                 _kvm_err(kd, kd->program, "out of memory");
 558         }
 559         return (np);
 560 }
 561
 562 #ifndef MAX
 563 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 564 #endif
 565
 566 /*
 567  * Read in an argument vector from the user address space of process pid.
 568  * addr if the user-space base address of narg null-terminated contiguous
 569  * strings.  This is used to read in both the command arguments and
 570  * environment strings.  Read at most maxcnt characters of strings.
 571  */
 572 static char **
 573 kvm_argv(kvm_t *kd, pid_t pid, u_long addr, int narg, int maxcnt)
 574 {
 575         char *np, *cp, *ep, *ap;
 576         u_long oaddr = -1;
 577         u_long addr_min = VM_MIN_USER_ADDRESS;
 578         u_long addr_max = VM_MAX_USER_ADDRESS;
 579         int len, cc;
 580         char **argv;
 581
 582         /*
 583          * Check that there aren't an unreasonable number of agruments,
 584          * and that the address is in user space.
 585          */
 586         if (narg > 512 || addr < addr_min || addr >= addr_max)
 587                 return (0);
 588
 589         /*
 590          * kd->argv : work space for fetching the strings from the target
 591          *            process's space, and is converted for returning to caller
 592          */
 593         if (kd->argv == 0) {
 594                 /*
 595                  * Try to avoid reallocs.
 596                  */
 597                 kd->argc = MAX(narg + 1, 32);
 598                 kd->argv = (char **)_kvm_malloc(kd, kd->argc *
 599                                                 sizeof(*kd->argv));
 600                 if (kd->argv == 0)
 601                         return (0);
 602         } else if (narg + 1 > kd->argc) {
 603                 kd->argc = MAX(2 * kd->argc, narg + 1);
 604                 kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
 605                                                 sizeof(*kd->argv));
 606                 if (kd->argv == 0)
 607                         return (0);
 608         }
 609         /*
 610          * kd->argspc : returned to user, this is where the kd->argv
 611          *              arrays are left pointing to the collected strings.
 612          */
 613         if (kd->argspc == 0) {
 614                 kd->argspc = (char *)_kvm_malloc(kd, PAGE_SIZE);
 615                 if (kd->argspc == 0)
 616                         return (0);
 617                 kd->arglen = PAGE_SIZE;
 618         }
 619         /*
 620          * kd->argbuf : used to pull in pages from the target process.
 621          *              the strings are copied out of here.
 622          */
 623         if (kd->argbuf == 0) {
 624                 kd->argbuf = (char *)_kvm_malloc(kd, PAGE_SIZE);
 625                 if (kd->argbuf == 0)
 626                         return (0);
 627         }
 628
 629         /* Pull in the target process'es argv vector */
 630         cc = sizeof(char *) * narg;
 631         if (kvm_uread(kd, pid, addr, (char *)kd->argv, cc) != cc)
 632                 return (0);
 633         /*
 634          * ap : saved start address of string we're working on in kd->argspc
 635          * np : pointer to next place to write in kd->argspc
 636          * len: length of data in kd->argspc
 637          * argv: pointer to the argv vector that we are hunting around the
 638          *       target process space for, and converting to addresses in
 639          *       our address space (kd->argspc).
 640          */
 641         ap = np = kd->argspc;
 642         argv = kd->argv;
 643         len = 0;
 644         /*
 645          * Loop over pages, filling in the argument vector.
 646          * Note that the argv strings could be pointing *anywhere* in
 647          * the user address space and are no longer contiguous.
 648          * Note that *argv is modified when we are going to fetch a string
 649          * that crosses a page boundary.  We copy the next part of the string
 650          * into to "np" and eventually convert the pointer.
 651          */
 652         while (argv < kd->argv + narg && *argv != NULL) {
 653
 654                 /* get the address that the current argv string is on */
 655                 addr = (u_long)*argv & ~(PAGE_SIZE - 1);
 656
 657                 /* is it the same page as the last one? */
 658                 if (addr != oaddr) {
 659                         if (kvm_uread(kd, pid, addr, kd->argbuf, PAGE_SIZE) !=
 660                             PAGE_SIZE)
 661                                 return (0);
 662                         oaddr = addr;
 663                 }
 664
 665                 /* offset within the page... kd->argbuf */
 666                 addr = (u_long)*argv & (PAGE_SIZE - 1);
 667
 668                 /* cp = start of string, cc = count of chars in this chunk */
 669                 cp = kd->argbuf + addr;
 670                 cc = PAGE_SIZE - addr;
 671
 672                 /* dont get more than asked for by user process */
 673                 if (maxcnt > 0 && cc > maxcnt - len)
 674                         cc = maxcnt - len;
 675
 676                 /* pointer to end of string if we found it in this page */
 677                 ep = memchr(cp, '\0', cc);
 678                 if (ep != NULL)
 679                         cc = ep - cp + 1;
 680                 /*
 681                  * at this point, cc is the count of the chars that we are
 682                  * going to retrieve this time. we may or may not have found
 683                  * the end of it.  (ep points to the null if the end is known)
 684                  */
 685
 686                 /* will we exceed the malloc/realloced buffer? */
 687                 if (len + cc > kd->arglen) {
 688                         size_t off;
 689                         char **pp;
 690                         char *op = kd->argspc;
 691
 692                         kd->arglen *= 2;
 693                         kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
 694                                                           kd->arglen);
 695                         if (kd->argspc == 0)
 696                                 return (0);
 697                         /*
 698                          * Adjust argv pointers in case realloc moved
 699                          * the string space.
 700                          */
 701                         off = kd->argspc - op;
 702                         for (pp = kd->argv; pp < argv; pp++)
 703                                 *pp += off;
 704                         ap += off;
 705                         np += off;
 706                 }
 707                 /* np = where to put the next part of the string in kd->argspc*/
 708                 /* np is kinda redundant.. could use "kd->argspc + len" */
 709                 memcpy(np, cp, cc);
 710                 np += cc;       /* inc counters */
 711                 len += cc;
 712
 713                 /*
 714                  * if end of string found, set the *argv pointer to the
 715                  * saved beginning of string, and advance. argv points to
 716                  * somewhere in kd->argv..  This is initially relative
 717                  * to the target process, but when we close it off, we set
 718                  * it to point in our address space.
 719                  */
 720                 if (ep != NULL) {
 721                         *argv++ = ap;
 722                         ap = np;
 723                 } else {
 724                         /* update the address relative to the target process */
 725                         *argv += cc;
 726                 }
 727
 728                 if (maxcnt > 0 && len >= maxcnt) {
 729                         /*
 730                          * We're stopping prematurely.  Terminate the
 731                          * current string.
 732                          */
 733                         if (ep == NULL) {
 734                                 *np = '\0';
 735                                 *argv++ = ap;
 736                         }
 737                         break;
 738                 }
 739         }
 740         /* Make sure argv is terminated. */
 741         *argv = NULL;
 742         return (kd->argv);
 743 }
 744
 745 static void
 746 ps_str_a(struct ps_strings *p, u_long *addr, int *n)
 747 {
 748         *addr = (u_long)p->ps_argvstr;
 749         *n = p->ps_nargvstr;
 750 }
 751
 752 static void
 753 ps_str_e(struct ps_strings *p, u_long *addr, int *n)
 754 {
 755         *addr = (u_long)p->ps_envstr;
 756         *n = p->ps_nenvstr;
 757 }
 758
 759 /*
 760  * Determine if the proc indicated by p is still active.
 761  * This test is not 100% foolproof in theory, but chances of
 762  * being wrong are very low.
 763  */
 764 static int
 765 proc_verify(const struct kinfo_proc *p)
 766 {
 767         struct kinfo_proc kp;
 768         int mib[4];
 769         size_t len;
 770         int error;
 771
 772         mib[0] = CTL_KERN;
 773         mib[1] = KERN_PROC;
 774         mib[2] = KERN_PROC_PID;
 775         mib[3] = p->kp_pid;
 776
 777         len = sizeof(kp);
 778         error = sysctl(mib, 4, &kp, &len, NULL, 0);
 779         if (error)
 780                 return (0);
 781
 782         error = (p->kp_pid == kp.kp_pid &&
 783             (kp.kp_stat != SZOMB || p->kp_stat == SZOMB));
 784         return (error);
 785 }
 786
 787 static char **
 788 kvm_doargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr,
 789            void (*info)(struct ps_strings *, u_long *, int *))
 790 {
 791         char **ap;
 792         u_long addr;
 793         int cnt;
 794         static struct ps_strings arginfo;
 795         static u_long ps_strings;
 796         size_t len;
 797
 798         if (ps_strings == 0) {
 799                 len = sizeof(ps_strings);
 800                 if (sysctlbyname("kern.ps_strings", &ps_strings, &len, NULL,
 801                     0) == -1)
 802                         ps_strings = PS_STRINGS;
 803         }
 804
 805         /*
 806          * Pointers are stored at the top of the user stack.
 807          */
 808         if (kp->kp_stat == SZOMB ||
 809             kvm_uread(kd, kp->kp_pid, ps_strings, (char *)&arginfo,
 810                       sizeof(arginfo)) != sizeof(arginfo))
 811                 return (0);
 812
 813         (*info)(&arginfo, &addr, &cnt);
 814         if (cnt == 0)
 815                 return (0);
 816         ap = kvm_argv(kd, kp->kp_pid, addr, cnt, nchr);
 817         /*
 818          * For live kernels, make sure this process didn't go away.
 819          */
 820         if (ap != NULL && (kvm_ishost(kd) || kvm_isvkernel(kd)) &&
 821             !proc_verify(kp))
 822                 ap = NULL;
 823         return (ap);
 824 }
 825
 826 /*
 827  * Get the command args.  This code is now machine independent.
 828  */
 829 char **
 830 kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
 831 {
 832         int oid[4];
 833         int i;
 834         size_t bufsz;
 835         static unsigned long buflen;
 836         static char *buf, *p;
 837         static char **bufp;
 838         static int argc;
 839
 840         if (!kvm_ishost(kd)) { /* XXX: vkernels */
 841                 _kvm_err(kd, kd->program,
 842                     "cannot read user space from dead kernel");
 843                 return (0);
 844         }
 845
 846         if (!buflen) {
 847                 bufsz = sizeof(buflen);
 848                 i = sysctlbyname("kern.ps_arg_cache_limit",
 849                     &buflen, &bufsz, NULL, 0);
 850                 if (i == -1) {
 851                         buflen = 0;
 852                 } else {
 853                         buf = malloc(buflen);
 854                         if (buf == NULL)
 855                                 buflen = 0;
 856                         argc = 32;
 857                         bufp = malloc(sizeof(char *) * argc);
 858                 }
 859         }
 860         if (buf != NULL) {
 861                 oid[0] = CTL_KERN;
 862                 oid[1] = KERN_PROC;
 863                 oid[2] = KERN_PROC_ARGS;
 864                 oid[3] = kp->kp_pid;
 865                 bufsz = buflen;
 866                 i = sysctl(oid, 4, buf, &bufsz, 0, 0);
 867                 if (i == 0 && bufsz > 0) {
 868                         i = 0;
 869                         p = buf;
 870                         do {
 871                                 bufp[i++] = p;
 872                                 p += strlen(p) + 1;
 873                                 if (i >= argc) {
 874                                         argc += argc;
 875                                         bufp = realloc(bufp,
 876                                             sizeof(char *) * argc);
 877                                 }
 878                         } while (p < buf + bufsz);
 879                         bufp[i++] = NULL;
 880                         return (bufp);
 881                 }
 882         }
 883         if (kp->kp_flags & P_SYSTEM)
 884                 return (NULL);
 885         return (kvm_doargv(kd, kp, nchr, ps_str_a));
 886 }
 887
 888 char **
 889 kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
 890 {
 891         return (kvm_doargv(kd, kp, nchr, ps_str_e));
 892 }
 893
 894 /*
 895  * Read from user space.  The user context is given by pid.
 896  */
 897 ssize_t
 898 kvm_uread(kvm_t *kd, pid_t pid, u_long uva, char *buf, size_t len)
 899 {
 900         char *cp;
 901         char procfile[MAXPATHLEN];
 902         ssize_t amount;
 903         int fd;
 904
 905         if (!kvm_ishost(kd)) { /* XXX: vkernels */
 906                 _kvm_err(kd, kd->program,
 907                     "cannot read user space from dead kernel");
 908                 return (0);
 909         }
 910
 911         sprintf(procfile, "/proc/%d/mem", pid);
 912         fd = open(procfile, O_RDONLY, 0);
 913         if (fd < 0) {
 914                 _kvm_err(kd, kd->program, "cannot open %s", procfile);
 915                 close(fd);
 916                 return (0);
 917         }
 918
 919         cp = buf;
 920         while (len > 0) {
 921                 errno = 0;
 922                 if (lseek(fd, (off_t)uva, 0) == -1 && errno != 0) {
 923                         _kvm_err(kd, kd->program, "invalid address (%lx) in %s",
 924                             uva, procfile);
 925                         break;
 926                 }
 927                 amount = read(fd, cp, len);
 928                 if (amount < 0) {
 929                         _kvm_syserr(kd, kd->program, "error reading %s",
 930                             procfile);
 931                         break;
 932                 }
 933                 if (amount == 0) {
 934                         _kvm_err(kd, kd->program, "EOF reading %s", procfile);
 935                         break;
 936                 }
 937                 cp += amount;
 938                 uva += amount;
 939                 len -= amount;
 940         }
 941
 942         close(fd);
 943         return ((ssize_t)(cp - buf));
 944 }