f2a2857bb3
the gating of system calls that cause modifications to the underlying filesystem. The gating can be enabled by any filesystem that needs to consistently suspend operations by adding the vop_stdgetwritemount to their set of vnops. Once gating is enabled, the function vfs_write_suspend stops all new write operations to a filesystem, allows any filesystem modifying system calls already in progress to complete, then sync's the filesystem to disk and returns. The function vfs_write_resume allows the suspended write operations to begin again. Gating is not added by default for all filesystems as for SMP systems it adds two extra locks to such critical kernel paths as the write system call. Thus, gating should only be added as needed. Details on the use and current status of snapshots in FFS can be found in /sys/ufs/ffs/README.snapshot so for brevity and timelyness is not included here. Unless and until you create a snapshot file, these changes should have no effect on your system (famous last words).
539 lines
12 KiB
C
539 lines
12 KiB
C
/*
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_ktrace.c 8.2 (Berkeley) 9/23/93
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* $FreeBSD$
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*/
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#include "opt_ktrace.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/fcntl.h>
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#include <sys/lock.h>
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#include <sys/namei.h>
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#include <sys/vnode.h>
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#include <sys/ktrace.h>
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#include <sys/malloc.h>
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#include <sys/syslog.h>
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#include <stddef.h>
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static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
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#ifdef KTRACE
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static struct ktr_header *ktrgetheader __P((int type));
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static void ktrwrite __P((struct vnode *, struct ktr_header *, struct uio *));
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static int ktrcanset __P((struct proc *,struct proc *));
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static int ktrsetchildren __P((struct proc *,struct proc *,int,int,struct vnode *));
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static int ktrops __P((struct proc *,struct proc *,int,int,struct vnode *));
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static struct ktr_header *
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ktrgetheader(type)
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int type;
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{
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register struct ktr_header *kth;
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struct proc *p = curproc; /* XXX */
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MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
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M_KTRACE, M_WAITOK);
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kth->ktr_type = type;
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microtime(&kth->ktr_time);
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kth->ktr_pid = p->p_pid;
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bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
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return (kth);
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}
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void
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ktrsyscall(vp, code, narg, args)
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struct vnode *vp;
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int code, narg;
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register_t args[];
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{
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struct ktr_header *kth;
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struct ktr_syscall *ktp;
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register int len = offsetof(struct ktr_syscall, ktr_args) +
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(narg * sizeof(register_t));
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struct proc *p = curproc; /* XXX */
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register_t *argp;
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int i;
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p->p_traceflag |= KTRFAC_ACTIVE;
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kth = ktrgetheader(KTR_SYSCALL);
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MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
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ktp->ktr_code = code;
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ktp->ktr_narg = narg;
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argp = &ktp->ktr_args[0];
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for (i = 0; i < narg; i++)
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*argp++ = args[i];
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kth->ktr_buf = (caddr_t)ktp;
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kth->ktr_len = len;
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ktrwrite(vp, kth, NULL);
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FREE(ktp, M_KTRACE);
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FREE(kth, M_KTRACE);
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p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
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void
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ktrsysret(vp, code, error, retval)
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struct vnode *vp;
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int code, error;
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register_t retval;
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{
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struct ktr_header *kth;
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struct ktr_sysret ktp;
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struct proc *p = curproc; /* XXX */
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p->p_traceflag |= KTRFAC_ACTIVE;
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kth = ktrgetheader(KTR_SYSRET);
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ktp.ktr_code = code;
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ktp.ktr_error = error;
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ktp.ktr_retval = retval; /* what about val2 ? */
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kth->ktr_buf = (caddr_t)&ktp;
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kth->ktr_len = sizeof(struct ktr_sysret);
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ktrwrite(vp, kth, NULL);
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FREE(kth, M_KTRACE);
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p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
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void
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ktrnamei(vp, path)
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struct vnode *vp;
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char *path;
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{
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struct ktr_header *kth;
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struct proc *p = curproc; /* XXX */
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p->p_traceflag |= KTRFAC_ACTIVE;
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kth = ktrgetheader(KTR_NAMEI);
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kth->ktr_len = strlen(path);
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kth->ktr_buf = path;
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ktrwrite(vp, kth, NULL);
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FREE(kth, M_KTRACE);
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p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
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void
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ktrgenio(vp, fd, rw, uio, error)
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struct vnode *vp;
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int fd;
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enum uio_rw rw;
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struct uio *uio;
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int error;
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{
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struct ktr_header *kth;
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struct ktr_genio ktg;
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struct proc *p = curproc; /* XXX */
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if (error)
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return;
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p->p_traceflag |= KTRFAC_ACTIVE;
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kth = ktrgetheader(KTR_GENIO);
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ktg.ktr_fd = fd;
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ktg.ktr_rw = rw;
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kth->ktr_buf = (caddr_t)&ktg;
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kth->ktr_len = sizeof(struct ktr_genio);
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uio->uio_offset = 0;
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uio->uio_rw = UIO_WRITE;
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ktrwrite(vp, kth, uio);
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FREE(kth, M_KTRACE);
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p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
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void
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ktrpsig(vp, sig, action, mask, code)
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struct vnode *vp;
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int sig;
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sig_t action;
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sigset_t *mask;
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int code;
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{
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struct ktr_header *kth;
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struct ktr_psig kp;
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struct proc *p = curproc; /* XXX */
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p->p_traceflag |= KTRFAC_ACTIVE;
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kth = ktrgetheader(KTR_PSIG);
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kp.signo = (char)sig;
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kp.action = action;
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kp.mask = *mask;
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kp.code = code;
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kth->ktr_buf = (caddr_t)&kp;
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kth->ktr_len = sizeof (struct ktr_psig);
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ktrwrite(vp, kth, NULL);
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FREE(kth, M_KTRACE);
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p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
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void
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ktrcsw(vp, out, user)
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struct vnode *vp;
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int out, user;
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{
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struct ktr_header *kth;
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struct ktr_csw kc;
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struct proc *p = curproc; /* XXX */
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p->p_traceflag |= KTRFAC_ACTIVE;
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kth = ktrgetheader(KTR_CSW);
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kc.out = out;
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kc.user = user;
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kth->ktr_buf = (caddr_t)&kc;
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kth->ktr_len = sizeof (struct ktr_csw);
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ktrwrite(vp, kth, NULL);
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FREE(kth, M_KTRACE);
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p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
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#endif
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/* Interface and common routines */
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/*
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* ktrace system call
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct ktrace_args {
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char *fname;
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int ops;
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int facs;
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int pid;
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};
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#endif
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/* ARGSUSED */
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int
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ktrace(curp, uap)
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struct proc *curp;
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register struct ktrace_args *uap;
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{
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#ifdef KTRACE
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register struct vnode *vp = NULL;
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register struct proc *p;
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struct pgrp *pg;
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int facs = uap->facs & ~KTRFAC_ROOT;
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int ops = KTROP(uap->ops);
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int descend = uap->ops & KTRFLAG_DESCEND;
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int ret = 0;
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int flags, error = 0;
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struct nameidata nd;
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curp->p_traceflag |= KTRFAC_ACTIVE;
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if (ops != KTROP_CLEAR) {
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/*
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* an operation which requires a file argument.
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*/
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NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, curp);
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flags = FREAD | FWRITE | O_NOFOLLOW;
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error = vn_open(&nd, &flags, 0);
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if (error) {
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curp->p_traceflag &= ~KTRFAC_ACTIVE;
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return (error);
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}
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NDFREE(&nd, NDF_ONLY_PNBUF);
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vp = nd.ni_vp;
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VOP_UNLOCK(vp, 0, curp);
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if (vp->v_type != VREG) {
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(void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
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curp->p_traceflag &= ~KTRFAC_ACTIVE;
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return (EACCES);
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}
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}
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/*
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* Clear all uses of the tracefile
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*/
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if (ops == KTROP_CLEARFILE) {
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LIST_FOREACH(p, &allproc, p_list) {
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if (p->p_tracep == vp) {
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if (ktrcanset(curp, p)) {
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p->p_tracep = NULL;
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p->p_traceflag = 0;
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(void) vn_close(vp, FREAD|FWRITE,
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p->p_ucred, p);
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} else
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error = EPERM;
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}
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}
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goto done;
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}
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/*
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* need something to (un)trace (XXX - why is this here?)
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*/
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if (!facs) {
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error = EINVAL;
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goto done;
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}
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/*
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* do it
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*/
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if (uap->pid < 0) {
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/*
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* by process group
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*/
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pg = pgfind(-uap->pid);
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if (pg == NULL) {
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error = ESRCH;
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goto done;
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}
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LIST_FOREACH(p, &pg->pg_members, p_pglist)
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if (descend)
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ret |= ktrsetchildren(curp, p, ops, facs, vp);
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else
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ret |= ktrops(curp, p, ops, facs, vp);
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} else {
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/*
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* by pid
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*/
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p = pfind(uap->pid);
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if (p == NULL) {
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error = ESRCH;
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goto done;
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}
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if (descend)
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ret |= ktrsetchildren(curp, p, ops, facs, vp);
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else
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ret |= ktrops(curp, p, ops, facs, vp);
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}
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if (!ret)
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error = EPERM;
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done:
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if (vp != NULL)
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(void) vn_close(vp, FWRITE, curp->p_ucred, curp);
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curp->p_traceflag &= ~KTRFAC_ACTIVE;
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return (error);
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#else
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return ENOSYS;
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#endif
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}
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/*
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* utrace system call
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*/
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/* ARGSUSED */
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int
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utrace(curp, uap)
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struct proc *curp;
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register struct utrace_args *uap;
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{
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#ifdef KTRACE
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struct ktr_header *kth;
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struct proc *p = curproc; /* XXX */
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register caddr_t cp;
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if (!KTRPOINT(p, KTR_USER))
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return (0);
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p->p_traceflag |= KTRFAC_ACTIVE;
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kth = ktrgetheader(KTR_USER);
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MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
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if (!copyin(uap->addr, cp, uap->len)) {
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kth->ktr_buf = cp;
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kth->ktr_len = uap->len;
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ktrwrite(p->p_tracep, kth, NULL);
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}
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FREE(kth, M_KTRACE);
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FREE(cp, M_KTRACE);
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p->p_traceflag &= ~KTRFAC_ACTIVE;
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return (0);
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#else
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return (ENOSYS);
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#endif
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}
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#ifdef KTRACE
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static int
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ktrops(curp, p, ops, facs, vp)
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struct proc *p, *curp;
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int ops, facs;
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struct vnode *vp;
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{
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if (!ktrcanset(curp, p))
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return (0);
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if (ops == KTROP_SET) {
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if (p->p_tracep != vp) {
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/*
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* if trace file already in use, relinquish
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*/
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if (p->p_tracep != NULL)
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vrele(p->p_tracep);
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VREF(vp);
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p->p_tracep = vp;
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}
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p->p_traceflag |= facs;
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if (curp->p_ucred->cr_uid == 0)
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p->p_traceflag |= KTRFAC_ROOT;
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} else {
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/* KTROP_CLEAR */
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if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
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/* no more tracing */
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p->p_traceflag = 0;
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if (p->p_tracep != NULL) {
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vrele(p->p_tracep);
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p->p_tracep = NULL;
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}
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}
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}
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return (1);
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}
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static int
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ktrsetchildren(curp, top, ops, facs, vp)
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struct proc *curp, *top;
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int ops, facs;
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struct vnode *vp;
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{
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register struct proc *p;
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register int ret = 0;
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p = top;
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for (;;) {
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ret |= ktrops(curp, p, ops, facs, vp);
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/*
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* If this process has children, descend to them next,
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* otherwise do any siblings, and if done with this level,
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* follow back up the tree (but not past top).
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*/
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if (!LIST_EMPTY(&p->p_children))
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p = LIST_FIRST(&p->p_children);
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else for (;;) {
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if (p == top)
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return (ret);
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if (LIST_NEXT(p, p_sibling)) {
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p = LIST_NEXT(p, p_sibling);
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break;
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}
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p = p->p_pptr;
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}
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}
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/*NOTREACHED*/
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}
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static void
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ktrwrite(vp, kth, uio)
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struct vnode *vp;
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register struct ktr_header *kth;
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struct uio *uio;
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{
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struct uio auio;
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struct iovec aiov[2];
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struct proc *p = curproc; /* XXX */
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struct mount *mp;
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int error;
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if (vp == NULL)
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return;
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auio.uio_iov = &aiov[0];
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auio.uio_offset = 0;
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auio.uio_segflg = UIO_SYSSPACE;
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auio.uio_rw = UIO_WRITE;
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aiov[0].iov_base = (caddr_t)kth;
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aiov[0].iov_len = sizeof(struct ktr_header);
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auio.uio_resid = sizeof(struct ktr_header);
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auio.uio_iovcnt = 1;
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auio.uio_procp = curproc;
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if (kth->ktr_len > 0) {
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auio.uio_iovcnt++;
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aiov[1].iov_base = kth->ktr_buf;
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aiov[1].iov_len = kth->ktr_len;
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auio.uio_resid += kth->ktr_len;
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if (uio != NULL)
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kth->ktr_len += uio->uio_resid;
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}
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vn_start_write(vp, &mp, V_WAIT);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
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(void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
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error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred);
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if (error == 0 && uio != NULL) {
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(void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
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error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred);
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}
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VOP_UNLOCK(vp, 0, p);
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vn_finished_write(mp);
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if (!error)
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return;
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/*
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* If error encountered, give up tracing on this vnode.
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*/
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log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
|
|
error);
|
|
LIST_FOREACH(p, &allproc, p_list) {
|
|
if (p->p_tracep == vp) {
|
|
p->p_tracep = NULL;
|
|
p->p_traceflag = 0;
|
|
vrele(vp);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return true if caller has permission to set the ktracing state
|
|
* of target. Essentially, the target can't possess any
|
|
* more permissions than the caller. KTRFAC_ROOT signifies that
|
|
* root previously set the tracing status on the target process, and
|
|
* so, only root may further change it.
|
|
*
|
|
* TODO: check groups. use caller effective gid.
|
|
*/
|
|
static int
|
|
ktrcanset(callp, targetp)
|
|
struct proc *callp, *targetp;
|
|
{
|
|
register struct pcred *caller = callp->p_cred;
|
|
register struct pcred *target = targetp->p_cred;
|
|
|
|
if (!PRISON_CHECK(callp, targetp))
|
|
return (0);
|
|
if ((caller->pc_ucred->cr_uid == target->p_ruid &&
|
|
target->p_ruid == target->p_svuid &&
|
|
caller->p_rgid == target->p_rgid && /* XXX */
|
|
target->p_rgid == target->p_svgid &&
|
|
(targetp->p_traceflag & KTRFAC_ROOT) == 0) ||
|
|
caller->pc_ucred->cr_uid == 0)
|
|
return (1);
|
|
|
|
return (0);
|
|
}
|
|
|
|
#endif /* KTRACE */
|