IABSD.fr/src/lib/libkvm/kvm_proc.c

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• Author : asou
  Date : 2024-05-10 06:46:14
  Hash : 6e552b66
  Message : Correct display the details of COMMAND using the ps command from the kernel crash dump. OK millert@

• lib/libkvm/kvm_proc.c

• /*	$OpenBSD: kvm_proc.c,v 1.64 2024/05/10 06:46:14 asou Exp $	*/
  /*	$NetBSD: kvm_proc.c,v 1.30 1999/03/24 05:50:50 mrg Exp $	*/
  /*-
   * Copyright (c) 1998 The NetBSD Foundation, Inc.
   * All rights reserved.
   *
   * This code is derived from software contributed to The NetBSD Foundation
   * by Charles M. Hannum.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  /*-
   * Copyright (c) 1994, 1995 Charles M. Hannum.  All rights reserved.
   * Copyright (c) 1989, 1992, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * This code is derived from software developed by the Computer Systems
   * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
   * BG 91-66 and contributed to Berkeley.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  /*
   * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
   * users of this code, so we've factored it out into a separate module.
   * Thus, we keep this grunge out of the other kvm applications (i.e.,
   * most other applications are interested only in open/close/read/nlist).
   */
  
  #define __need_process
  #include <sys/param.h>	/* VM_MIN_ADDRESS PAGE_SIZE */
  #include <sys/types.h>
  #include <sys/signal.h>
  #include <sys/proc.h>
  #include <sys/exec.h>
  #include <sys/stat.h>
  #include <sys/ioctl.h>
  #include <sys/tty.h>
  #include <stddef.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <nlist.h>
  #include <kvm.h>
  #include <errno.h>
  
  #include <uvm/uvm_extern.h>
  #include <uvm/uvm_amap.h>
  #include <machine/vmparam.h>
  #include <machine/pmap.h>
  
  #include <sys/sysctl.h>
  
  #include <limits.h>
  #include <db.h>
  #include <paths.h>
  
  #include "kvm_private.h"
  
  #define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
  #define MAXIMUM(a, b)	(((a) > (b)) ? (a) : (b))
  
  static char	*_kvm_ureadm(kvm_t *, const struct kinfo_proc *, u_long, u_long *);
  static ssize_t	kvm_ureadm(kvm_t *, const struct kinfo_proc *, u_long, char *, size_t);
  
  static char	**kvm_argv(kvm_t *, const struct kinfo_proc *, u_long, int, int, int);
  
  static char	**kvm_doargv(kvm_t *, const struct kinfo_proc *, int, int,
  		    void (*)(struct ps_strings *, u_long *, int *));
  static int	proc_verify(kvm_t *, const struct kinfo_proc *);
  static void	ps_str_a(struct ps_strings *, u_long *, int *);
  static void	ps_str_e(struct ps_strings *, u_long *, int *);
  
  static struct vm_anon *
  _kvm_findanon(kvm_t *kd, struct vm_amap *amapp, int slot)
  {
  	u_long addr;
  	int bucket;
  	struct vm_amap amap;
  	struct vm_amap_chunk chunk, *chunkp;
  	struct vm_anon *anonp;
  
  	addr = (u_long)amapp;
  	if (KREAD(kd, addr, &amap))
  		return (NULL);
  
  	/* sanity-check slot number */
  	if (slot > amap.am_nslot)
  		return (NULL);
  
  	if (UVM_AMAP_SMALL(&amap))
  		chunkp = &amapp->am_small;
  	else {
  		bucket = UVM_AMAP_BUCKET(&amap, slot);
  		addr = (u_long)(amap.am_buckets + bucket);
  		if (KREAD(kd, addr, &chunkp))
  			return (NULL);
  
  		while (chunkp != NULL) {
  			addr = (u_long)chunkp;
  			if (KREAD(kd, addr, &chunk))
  				return (NULL);
  
  			if (UVM_AMAP_BUCKET(&amap, chunk.ac_baseslot) !=
  			    bucket)
  				return (NULL);
  			if (slot >= chunk.ac_baseslot &&
  			    slot < chunk.ac_baseslot + chunk.ac_nslot)
  				break;
  
  			chunkp = TAILQ_NEXT(&chunk, ac_list);
  		}
  		if (chunkp == NULL)
  			return (NULL);
  	}
  
  	addr = (u_long)&chunkp->ac_anon[UVM_AMAP_SLOTIDX(slot)];
  	if (KREAD(kd, addr, &anonp))
  		return (NULL);
  
  	return (anonp);
  }
  
  static char *
  _kvm_ureadm(kvm_t *kd, const struct kinfo_proc *p, u_long va, u_long *cnt)
  {
  	u_long addr, offset, slot;
  	struct vmspace vm;
  	struct vm_anon *anonp, anon;
  	struct vm_map_entry vme;
  	struct vm_page pg;
  	unsigned long rboff;
  
  	if (kd->swapspc == 0) {
  		kd->swapspc = _kvm_malloc(kd, kd->nbpg);
  		if (kd->swapspc == 0)
  			return (NULL);
  	}
  
  	rboff = (unsigned long)&vme.daddrs.addr_entry - (unsigned long)&vme;
  
  	/*
  	 * Look through the address map for the memory object
  	 * that corresponds to the given virtual address.
  	 */
  	if (KREAD(kd, (u_long)p->p_vmspace, &vm))
  		return (NULL);
  	addr = (u_long)vm.vm_map.addr.rbh_root.rbt_root;
  	while (1) {
  		if (addr == 0)
  			return (NULL);
  		addr -= rboff;
  		if (KREAD(kd, addr, &vme))
  			return (NULL);
  
  		if (va < vme.start)
  			addr = (u_long)vme.daddrs.addr_entry.rbt_left;
  		else if (va >= vme.end + vme.guard + vme.fspace)
  			addr = (u_long)vme.daddrs.addr_entry.rbt_right;
  		else if (va >= vme.end)
  			return (NULL);
  		else
  			break;
  	}
  
  	/*
  	 * we found the map entry, now to find the object...
  	 */
  	if (vme.aref.ar_amap == NULL)
  		return (NULL);
  
  	offset = va - vme.start;
  	slot = offset / kd->nbpg + vme.aref.ar_pageoff;
  
  	anonp = _kvm_findanon(kd, vme.aref.ar_amap, slot);
  	if (anonp == NULL)
  		return (NULL);
  
  	addr = (u_long)anonp;
  	if (KREAD(kd, addr, &anon))
  		return (NULL);
  
  	addr = (u_long)anon.an_page;
  	if (addr) {
  		if (KREAD(kd, addr, &pg))
  			return (NULL);
  
  		if (_kvm_pread(kd, kd->pmfd, (void *)kd->swapspc,
  		    (size_t)kd->nbpg, _kvm_pa2off(kd, pg.phys_addr)) != kd->nbpg)
  			return (NULL);
  	} else {
  		if (kd->swfd == -1 ||
  		    _kvm_pread(kd, kd->swfd, (void *)kd->swapspc,
  		    (size_t)kd->nbpg,
  		    (off_t)(anon.an_swslot * kd->nbpg)) != kd->nbpg)
  			return (NULL);
  	}
  
  	/* Found the page. */
  	offset %= kd->nbpg;
  	*cnt = kd->nbpg - offset;
  	return (&kd->swapspc[offset]);
  }
  
  void *
  _kvm_reallocarray(kvm_t *kd, void *p, size_t i, size_t n)
  {
  	void *np = reallocarray(p, i, n);
  
  	if (np == 0)
  		_kvm_err(kd, kd->program, "out of memory");
  	return (np);
  }
  
  /*
   * Read in an argument vector from the user address space of process p.
   * addr if the user-space base address of narg null-terminated contiguous
   * strings.  This is used to read in both the command arguments and
   * environment strings.  Read at most maxcnt characters of strings.
   */
  static char **
  kvm_argv(kvm_t *kd, const struct kinfo_proc *p, u_long addr, int narg,
      int maxcnt, int isenv)
  {
  	char *np, *cp, *ep, *ap, **argv, ***pargv, **pargspc, **pargbuf;
  	u_long oaddr = -1;
  	int len, cc, *parglen, *pargc;
  	size_t argc;
  
  	/*
  	 * Check that there aren't an unreasonable number of arguments,
  	 * and that the address is in user space.
  	 */
  	if (narg > ARG_MAX || addr < VM_MIN_ADDRESS || addr >= VM_MAXUSER_ADDRESS)
  		return (0);
  
  	if (isenv) {
  		pargspc = &kd->envspc;
  		pargbuf = &kd->envbuf;
  		parglen = &kd->envlen;
  		pargv = &kd->envp;
  		pargc = &kd->envc;
  	} else {
  		pargspc = &kd->argspc;
  		pargbuf = &kd->argbuf;
  		parglen = &kd->arglen;
  		pargv = &kd->argv;
  		pargc = &kd->argc;
  	}
  
  	if (*pargv == 0)
  		argc = MAXIMUM(narg + 1, 32);
  	else if (narg + 1 > *pargc)
  		argc = MAXIMUM(2 * (*pargc), narg + 1);
  	else
  		goto argv_allocated;
  	argv = _kvm_reallocarray(kd, *pargv, argc, sizeof(**pargv));
  	if (argv == 0)
  		return (0);
  	*pargv = argv;
  	*pargc = argc;
  
  argv_allocated:
  	if (*pargspc == 0) {
  		*pargspc = _kvm_malloc(kd, kd->nbpg);
  		if (*pargspc == 0)
  			return (0);
  		*parglen = kd->nbpg;
  	}
  	if (*pargbuf == 0) {
  		*pargbuf = _kvm_malloc(kd, kd->nbpg);
  		if (*pargbuf == 0)
  			return (0);
  	}
  	cc = sizeof(char *) * narg;
  	if (kvm_ureadm(kd, p, addr, (char *)*pargv, cc) != cc)
  		return (0);
  	ap = np = *pargspc;
  	argv = *pargv;
  	len = 0;
  
  	/*
  	 * Loop over pages, filling in the argument vector.
  	 */
  	while (argv < *pargv + narg && *argv != 0) {
  		addr = (u_long)*argv & ~(kd->nbpg - 1);
  		if (addr != oaddr) {
  			if (kvm_ureadm(kd, p, addr, *pargbuf, kd->nbpg) !=
  			    kd->nbpg)
  				return (0);
  			oaddr = addr;
  		}
  		addr = (u_long)*argv & (kd->nbpg - 1);
  		cp = *pargbuf + addr;
  		cc = kd->nbpg - addr;
  		if (maxcnt > 0 && cc > maxcnt - len)
  			cc = maxcnt - len;
  		ep = memchr(cp, '\0', cc);
  		if (ep != 0)
  			cc = ep - cp + 1;
  		if (len + cc > *parglen) {
  			ptrdiff_t off;
  			char **pp;
  			char *op = *pargspc;
  			char *newp;
  
  			newp = _kvm_reallocarray(kd, *pargspc,
  			    *parglen, 2);
  			if (newp == 0)
  				return (0);
  			*pargspc = newp;
  			*parglen *= 2;
  			/*
  			 * Adjust argv pointers in case realloc moved
  			 * the string space.
  			 */
  			off = *pargspc - op;
  			for (pp = *pargv; pp < argv; pp++)
  				*pp += off;
  			ap += off;
  			np += off;
  		}
  		memcpy(np, cp, cc);
  		np += cc;
  		len += cc;
  		if (ep != 0) {
  			*argv++ = ap;
  			ap = np;
  		} else
  			*argv += cc;
  		if (maxcnt > 0 && len >= maxcnt) {
  			/*
  			 * We're stopping prematurely.  Terminate the
  			 * current string.
  			 */
  			if (ep == 0) {
  				*np = '\0';
  				*argv++ = ap;
  			}
  			break;
  		}
  	}
  	/* Make sure argv is terminated. */
  	*argv = 0;
  	return (*pargv);
  }
  
  static void
  ps_str_a(struct ps_strings *p, u_long *addr, int *n)
  {
  	*addr = (u_long)p->ps_argvstr;
  	*n = p->ps_nargvstr;
  }
  
  static void
  ps_str_e(struct ps_strings *p, u_long *addr, int *n)
  {
  	*addr = (u_long)p->ps_envstr;
  	*n = p->ps_nenvstr;
  }
  
  /*
   * Determine if the proc indicated by p is still active.
   * This test is not 100% foolproof in theory, but chances of
   * being wrong are very low.
   */
  static int
  proc_verify(kvm_t *kd, const struct kinfo_proc *p)
  {
  	struct proc kernproc;
  	struct process kernprocess;
  
  	if (p->p_psflags & (PS_EMBRYO | PS_ZOMBIE))
  		return (0);
  
  	/*
  	 * Just read in the whole proc.  It's not that big relative
  	 * to the cost of the read system call.
  	 */
  	if (KREAD(kd, (u_long)p->p_paddr, &kernproc))
  		return (0);
  	if (KREAD(kd, (u_long)kernproc.p_p, &kernprocess))
  		return (0);
  	if (p->p_pid != kernprocess.ps_pid)
  		return (0);
  	return ((kernprocess.ps_flags & (PS_EMBRYO | PS_ZOMBIE)) == 0);
  }
  
  static char **
  kvm_doargv(kvm_t *kd, const struct kinfo_proc *p, int nchr, int isenv,
      void (*info)(struct ps_strings *, u_long *, int *))
  {
  	struct proc pp;
  	struct process pr;
  	struct ps_strings *ps;
  	struct ps_strings arginfo;
  	u_long addr;
  	char **ap;
  	int cnt;
  
  	/* get ps_strings address */
  	if (KREAD(kd, (u_long)p->p_paddr, &pp))
  		return (0);
  	if (KREAD(kd, (u_long)pp.p_p, &pr))
  		return (0);
  	ps = (struct ps_strings *)pr.ps_strings;
  
  	/*
  	 * Pointers are stored at the top of the user stack.
  	 */
  	if (p->p_psflags & (PS_EMBRYO | PS_ZOMBIE) ||
  	    kvm_ureadm(kd, p, (u_long)ps, (char *)&arginfo,
  	    sizeof(arginfo)) != sizeof(arginfo))
  		return (0);
  
  	(*info)(&arginfo, &addr, &cnt);
  	if (cnt == 0)
  		return (0);
  	ap = kvm_argv(kd, p, addr, cnt, nchr, isenv);
  	/*
  	 * For live kernels, make sure this process didn't go away.
  	 */
  	if (ap != 0 && ISALIVE(kd) && !proc_verify(kd, p))
  		ap = 0;
  	return (ap);
  }
  
  static char **
  kvm_arg_sysctl(kvm_t *kd, pid_t pid, int nchr, int isenv)
  {
  	size_t len, orglen;
  	int mib[4], ret;
  	char *buf, **pargbuf;
  
  	if (isenv) {
  		pargbuf = &kd->envbuf;
  		orglen = kd->nbpg;
  	} else {
  		pargbuf = &kd->argbuf;
  		orglen = 8 * kd->nbpg;	/* XXX - should be ARG_MAX */
  	}
  	if (*pargbuf == NULL &&
  	    (*pargbuf = _kvm_malloc(kd, orglen)) == NULL)
  		return (NULL);
  
  again:
  	mib[0] = CTL_KERN;
  	mib[1] = KERN_PROC_ARGS;
  	mib[2] = (int)pid;
  	mib[3] = isenv ? KERN_PROC_ENV : KERN_PROC_ARGV;
  
  	len = orglen;
  	ret = (sysctl(mib, 4, *pargbuf, &len, NULL, 0) == -1);
  	if (ret && errno == ENOMEM) {
  		buf = _kvm_reallocarray(kd, *pargbuf, orglen, 2);
  		if (buf == NULL)
  			return (NULL);
  		orglen *= 2;
  		*pargbuf = buf;
  		goto again;
  	}
  
  	if (ret) {
  		free(*pargbuf);
  		*pargbuf = NULL;
  		_kvm_syserr(kd, kd->program, "kvm_arg_sysctl");
  		return (NULL);
  	}
  #if 0
  	for (argv = (char **)*pargbuf; *argv != NULL; argv++)
  		if (strlen(*argv) > nchr)
  			*argv[nchr] = '\0';
  #endif
  
  	return (char **)(*pargbuf);
  }
  
  /*
   * Get the command args.  This code is now machine independent.
   */
  char **
  kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
  {
  	if (ISALIVE(kd))
  		return (kvm_arg_sysctl(kd, kp->p_pid, nchr, 0));
  	return (kvm_doargv(kd, kp, nchr, 0, ps_str_a));
  }
  
  char **
  kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
  {
  	if (ISALIVE(kd))
  		return (kvm_arg_sysctl(kd, kp->p_pid, nchr, 1));
  	return (kvm_doargv(kd, kp, nchr, 1, ps_str_e));
  }
  
  /*
   * Read from user space.  The user context is given by p.
   */
  static ssize_t
  kvm_ureadm(kvm_t *kd, const struct kinfo_proc *p, u_long uva, char *buf,
      size_t len)
  {
  	char *cp = buf;
  
  	while (len > 0) {
  		u_long cnt;
  		size_t cc;
  		char *dp;
  
  		dp = _kvm_ureadm(kd, p, uva, &cnt);
  		if (dp == 0) {
  			_kvm_err(kd, 0, "invalid address (%lx)", uva);
  			return (0);
  		}
  		cc = (size_t)MINIMUM(cnt, len);
  		memcpy(cp, dp, cc);
  		cp += cc;
  		uva += cc;
  		len -= cc;
  	}
  	return (ssize_t)(cp - buf);
  }