/* * Copyright (c) 1993 Jan-Simon Pendry * Copyright (c) 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry. * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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. * * @(#)procfs_vnops.c 8.6 (Berkeley) 2/7/94 * * $Id: procfs_vnops.c,v 1.7 1994/10/10 07:55:40 phk Exp $ */ /* * procfs vnode interface */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* for PAGE_SIZE */ /* * Vnode Operations. * */ /* * This is a list of the valid names in the * process-specific sub-directories. It is * used in procfs_lookup and procfs_readdir */ static struct pfsnames { u_short d_namlen; char d_name[PROCFS_NAMELEN]; pfstype d_pfstype; } procent[] = { #define N(s) sizeof(s)-1, s /* namlen, nam, type */ { N("."), Pproc }, { N(".."), Proot }, #if 0 { N("file"), Pfile }, #endif { N("mem"), Pmem }, { N("regs"), Pregs }, { N("fpregs"), Pfpregs }, { N("ctl"), Pctl }, { N("status"), Pstatus }, { N("note"), Pnote }, { N("notepg"), Pnotepg }, #undef N }; #define Nprocent (sizeof(procent)/sizeof(procent[0])) static pid_t atopid __P((const char *, u_int)); /* * set things up for doing i/o on * the pfsnode (vp). (vp) is locked * on entry, and should be left locked * on exit. * * for procfs we don't need to do anything * in particular for i/o. all that is done * is to support exclusive open on process * memory images. */ int procfs_open(ap) struct vop_open_args *ap; { struct pfsnode *pfs = VTOPFS(ap->a_vp); switch (pfs->pfs_type) { case Pmem: if (PFIND(pfs->pfs_pid) == 0) return (ENOENT); /* was ESRCH, jsp */ if (((pfs->pfs_flags & FWRITE) && (ap->a_mode & O_EXCL)) || ((pfs->pfs_flags & O_EXCL) && (ap->a_mode & FWRITE))) return (EBUSY); if (ap->a_mode & FWRITE) pfs->pfs_flags = ap->a_mode & (FWRITE|O_EXCL); return (0); default: break; } return (0); } /* * close the pfsnode (vp) after doing i/o. * (vp) is not locked on entry or exit. * * nothing to do for procfs other than undo * any exclusive open flag (see _open above). */ int procfs_close(ap) struct vop_close_args *ap; { struct pfsnode *pfs = VTOPFS(ap->a_vp); switch (pfs->pfs_type) { case Pmem: if ((ap->a_fflag & FWRITE) && (pfs->pfs_flags & O_EXCL)) pfs->pfs_flags &= ~(FWRITE|O_EXCL); break; default: break; } return (0); } /* * do an ioctl operation on pfsnode (vp). * (vp) is not locked on entry or exit. */ int procfs_ioctl(ap) struct vop_ioctl_args *ap; { return (ENOTTY); } /* * do block mapping for pfsnode (vp). * since we don't use the buffer cache * for procfs this function should never * be called. in any case, it's not clear * what part of the kernel ever makes use * of this function. for sanity, this is the * usual no-op bmap, although returning * (EIO) would be a reasonable alternative. */ int procfs_bmap(ap) struct vop_bmap_args *ap; { if (ap->a_vpp != NULL) *ap->a_vpp = ap->a_vp; if (ap->a_bnp != NULL) *ap->a_bnp = ap->a_bn; if (ap->a_runp != NULL) *ap->a_runp = 0; return (0); } /* * _inactive is called when the pfsnode * is vrele'd and the reference count goes * to zero. (vp) will be on the vnode free * list, so to get it back vget() must be * used. * * for procfs, check if the process is still * alive and if it isn't then just throw away * the vnode by calling vgone(). this may * be overkill and a waste of time since the * chances are that the process will still be * there and PFIND is not free. * * (vp) is not locked on entry or exit. */ int procfs_inactive(ap) struct vop_inactive_args *ap; { struct pfsnode *pfs = VTOPFS(ap->a_vp); if (PFIND(pfs->pfs_pid) == 0) vgone(ap->a_vp); return (0); } /* * _reclaim is called when getnewvnode() * wants to make use of an entry on the vnode * free list. at this time the filesystem needs * to free any private data and remove the node * from any private lists. */ int procfs_reclaim(ap) struct vop_reclaim_args *ap; { int error; error = procfs_freevp(ap->a_vp); return (error); } /* * Return POSIX pathconf information applicable to special devices. */ int procfs_pathconf(ap) struct vop_pathconf_args /* { struct vnode *a_vp; int a_name; int *a_retval; } */ *ap; { switch (ap->a_name) { case _PC_LINK_MAX: *ap->a_retval = LINK_MAX; return (0); case _PC_MAX_CANON: *ap->a_retval = MAX_CANON; return (0); case _PC_MAX_INPUT: *ap->a_retval = MAX_INPUT; return (0); case _PC_PIPE_BUF: *ap->a_retval = PIPE_BUF; return (0); case _PC_CHOWN_RESTRICTED: *ap->a_retval = 1; return (0); case _PC_VDISABLE: *ap->a_retval = _POSIX_VDISABLE; return (0); default: return (EINVAL); } /* NOTREACHED */ } /* * _print is used for debugging. * just print a readable description * of (vp). */ int procfs_print(ap) struct vop_print_args *ap; { struct pfsnode *pfs = VTOPFS(ap->a_vp); printf("tag VT_PROCFS, pid %lu, mode %x, flags %x\n", (u_long)pfs->pfs_pid, pfs->pfs_mode, pfs->pfs_flags); return (0); } /* * _abortop is called when operations such as * rename and create fail. this entry is responsible * for undoing any side-effects caused by the lookup. * this will always include freeing the pathname buffer. */ int procfs_abortop(ap) struct vop_abortop_args *ap; { if ((ap->a_cnp->cn_flags & (HASBUF | SAVESTART)) == HASBUF) FREE(ap->a_cnp->cn_pnbuf, M_NAMEI); return (0); } /* * generic entry point for unsupported operations */ int procfs_badop() { return (EIO); } /* * Invent attributes for pfsnode (vp) and store * them in (vap). * Directories lengths are returned as zero since * any real length would require the genuine size * to be computed, and nothing cares anyway. * * this is relatively minimal for procfs. */ int procfs_getattr(ap) struct vop_getattr_args *ap; { struct pfsnode *pfs = VTOPFS(ap->a_vp); struct vattr *vap = ap->a_vap; struct proc *procp; int error; /* first check the process still exists */ switch (pfs->pfs_type) { case Proot: procp = 0; break; default: procp = PFIND(pfs->pfs_pid); if (procp == 0) return (ENOENT); } error = 0; /* start by zeroing out the attributes */ VATTR_NULL(vap); /* next do all the common fields */ vap->va_type = ap->a_vp->v_type; vap->va_mode = pfs->pfs_mode; vap->va_fileid = pfs->pfs_fileno; vap->va_flags = 0; vap->va_blocksize = PAGE_SIZE; vap->va_bytes = vap->va_size = 0; /* * If the process has exercised some setuid or setgid * privilege, then rip away read/write permission so * that only root can gain access. */ switch (pfs->pfs_type) { case Pregs: case Pfpregs: case Pmem: if (procp->p_flag & P_SUGID) vap->va_mode &= ~((VREAD|VWRITE)| ((VREAD|VWRITE)>>3)| ((VREAD|VWRITE)>>6)); break; default: break; } /* * Make all times be current TOD. * It would be possible to get the process start * time from the p_stat structure, but there's * no "file creation" time stamp anyway, and the * p_stat structure is not addressible if u. gets * swapped out for that process. */ { struct timeval tv; microtime(&tv); TIMEVAL_TO_TIMESPEC(&tv, &vap->va_ctime); } vap->va_atime = vap->va_mtime = vap->va_ctime; /* * now do the object specific fields * * The size could be set from struct reg, but it's hardly * worth the trouble, and it puts some (potentially) machine * dependent data into this machine-independent code. If it * becomes important then this function should break out into * a per-file stat function in the corresponding .c file. */ switch (pfs->pfs_type) { case Proot: vap->va_nlink = nprocs + 3; vap->va_uid = 0; vap->va_gid = 0; vap->va_bytes = vap->va_size = DEV_BSIZE; break; case Pproc: vap->va_nlink = Nprocent; vap->va_uid = procp->p_ucred->cr_uid; vap->va_gid = procp->p_ucred->cr_gid; vap->va_bytes = vap->va_size = DEV_BSIZE; break; case Pfile: error = EOPNOTSUPP; break; case Pmem: vap->va_nlink = 1; vap->va_bytes = vap->va_size = ctob(procp->p_vmspace->vm_tsize + procp->p_vmspace->vm_dsize + procp->p_vmspace->vm_ssize); vap->va_uid = procp->p_ucred->cr_uid; vap->va_gid = procp->p_ucred->cr_gid; break; case Pregs: case Pfpregs: case Pctl: case Pstatus: case Pnote: case Pnotepg: vap->va_nlink = 1; vap->va_uid = procp->p_ucred->cr_uid; vap->va_gid = procp->p_ucred->cr_gid; break; default: panic("procfs_getattr"); } return (error); } int procfs_setattr(ap) struct vop_setattr_args *ap; { /* * just fake out attribute setting * it's not good to generate an error * return, otherwise things like creat() * will fail when they try to set the * file length to 0. worse, this means * that echo $note > /proc/$pid/note will fail. */ return (0); } /* * implement access checking. * * something very similar to this code is duplicated * throughout the 4bsd kernel and should be moved * into kern/vfs_subr.c sometime. * * actually, the check for super-user is slightly * broken since it will allow read access to write-only * objects. this doesn't cause any particular trouble * but does mean that the i/o entry points need to check * that the operation really does make sense. */ int procfs_access(ap) struct vop_access_args *ap; { struct vattr *vap; struct vattr vattr; int error; /* * If you're the super-user, * you always get access. */ if (ap->a_cred->cr_uid == (uid_t) 0) return (0); vap = &vattr; error = VOP_GETATTR(ap->a_vp, vap, ap->a_cred, ap->a_p); if (error) return (error); /* * Access check is based on only one of owner, group, public. * If not owner, then check group. If not a member of the * group, then check public access. */ if (ap->a_cred->cr_uid != vap->va_uid) { gid_t *gp; int i; (ap->a_mode) >>= 3; gp = ap->a_cred->cr_groups; for (i = 0; i < ap->a_cred->cr_ngroups; i++, gp++) if (vap->va_gid == *gp) goto found; ap->a_mode >>= 3; found: ; } if ((vap->va_mode & ap->a_mode) == ap->a_mode) return (0); return (EACCES); } /* * lookup. this is incredibly complicated in the * general case, however for most pseudo-filesystems * very little needs to be done. * * unless you want to get a migraine, just make sure your * filesystem doesn't do any locking of its own. otherwise * read and inwardly digest ufs_lookup(). */ int procfs_lookup(ap) struct vop_lookup_args *ap; { struct componentname *cnp = ap->a_cnp; struct vnode **vpp = ap->a_vpp; struct vnode *dvp = ap->a_dvp; char *pname = cnp->cn_nameptr; int error = 0; pid_t pid; struct vnode *nvp; struct pfsnode *pfs; struct proc *procp; pfstype pfs_type; int i; if (cnp->cn_namelen == 1 && *pname == '.') { *vpp = dvp; VREF(dvp); /*VOP_LOCK(dvp);*/ return (0); } *vpp = NULL; pfs = VTOPFS(dvp); switch (pfs->pfs_type) { case Proot: if (cnp->cn_flags & ISDOTDOT) return (EIO); if (CNEQ(cnp, "curproc", 7)) pid = cnp->cn_proc->p_pid; else pid = atopid(pname, cnp->cn_namelen); if (pid == NO_PID) return (ENOENT); procp = PFIND(pid); if (procp == 0) return (ENOENT); error = procfs_allocvp(dvp->v_mount, &nvp, pid, Pproc); if (error) return (error); nvp->v_type = VDIR; pfs = VTOPFS(nvp); *vpp = nvp; return (0); case Pproc: if (cnp->cn_flags & ISDOTDOT) { error = procfs_root(dvp->v_mount, vpp); return (error); } procp = PFIND(pfs->pfs_pid); if (procp == 0) return (ENOENT); for (i = 0; i < Nprocent; i++) { struct pfsnames *dp = &procent[i]; if (cnp->cn_namelen == dp->d_namlen && bcmp(pname, dp->d_name, dp->d_namlen) == 0) { pfs_type = dp->d_pfstype; goto found; } } return (ENOENT); found: if (pfs_type == Pfile) { nvp = procfs_findtextvp(procp); if (nvp) { VREF(nvp); VOP_LOCK(nvp); } else { error = ENXIO; } } else { error = procfs_allocvp(dvp->v_mount, &nvp, pfs->pfs_pid, pfs_type); if (error) return (error); nvp->v_type = VREG; pfs = VTOPFS(nvp); } *vpp = nvp; return (error); default: return (ENOTDIR); } } /* * readdir returns directory entries from pfsnode (vp). * * the strategy here with procfs is to generate a single * directory entry at a time (struct pfsdent) and then * copy that out to userland using uiomove. a more efficent * though more complex implementation, would try to minimize * the number of calls to uiomove(). for procfs, this is * hardly worth the added code complexity. * * this should just be done through read() */ int procfs_readdir(ap) struct vop_readdir_args *ap; { struct uio *uio = ap->a_uio; struct pfsdent d; struct pfsdent *dp = &d; struct pfsnode *pfs; int error; int count; int i; pfs = VTOPFS(ap->a_vp); if (uio->uio_resid < UIO_MX) return (EINVAL); if (uio->uio_offset & (UIO_MX-1)) return (EINVAL); if (uio->uio_offset < 0) return (EINVAL); error = 0; count = 0; i = uio->uio_offset / UIO_MX; switch (pfs->pfs_type) { /* * this is for the process-specific sub-directories. * all that is needed to is copy out all the entries * from the procent[] table (top of this file). */ case Pproc: { while (uio->uio_resid >= UIO_MX) { struct pfsnames *dt; if (i >= Nprocent) break; dt = &procent[i]; dp->d_reclen = UIO_MX; dp->d_fileno = PROCFS_FILENO(pfs->pfs_pid, dt->d_pfstype); dp->d_type = DT_REG; dp->d_namlen = dt->d_namlen; bcopy(dt->d_name, dp->d_name, sizeof(dt->d_name)-1); error = uiomove((caddr_t) dp, UIO_MX, uio); if (error) break; count += UIO_MX; i++; } break; } /* * this is for the root of the procfs filesystem * what is needed is a special entry for "curproc" * followed by an entry for each process on allproc #ifdef PROCFS_ZOMBIE * and zombproc. #endif */ case Proot: { int pcnt; #ifdef PROCFS_ZOMBIE int doingzomb = 0; #endif volatile struct proc *p; p = allproc; #define PROCFS_XFILES 3 /* number of other entries, like "curproc" */ pcnt = PROCFS_XFILES; while (p && uio->uio_resid >= UIO_MX) { bzero((char *) dp, UIO_MX); dp->d_type = DT_DIR; dp->d_reclen = UIO_MX; switch (i) { case 0: dp->d_fileno = PROCFS_FILENO(0, Proot); dp->d_namlen = sprintf(dp->d_name, "."); break; case 1: dp->d_fileno = PROCFS_FILENO(0, Proot); dp->d_namlen = sprintf(dp->d_name, ".."); break; case 2: /* ship out entry for "curproc" */ dp->d_fileno = PROCFS_FILENO(PID_MAX+1, Pproc); dp->d_namlen = sprintf(dp->d_name, "curproc"); break; default: if (pcnt >= i) { dp->d_fileno = PROCFS_FILENO(p->p_pid, Pproc); dp->d_namlen = sprintf(dp->d_name, "%ld", (long) p->p_pid); } p = p->p_next; #ifdef PROCFS_ZOMBIE if (p == 0 && doingzomb == 0) { doingzomb = 1; p = zombproc; } #endif if (pcnt++ < i) continue; break; } error = uiomove((caddr_t) dp, UIO_MX, uio); if (error) break; count += UIO_MX; i++; } break; } default: error = ENOTDIR; break; } uio->uio_offset = i * UIO_MX; return (error); } /* * convert decimal ascii to pid_t */ static pid_t atopid(b, len) const char *b; u_int len; { pid_t p = 0; while (len--) { char c = *b++; if (c < '0' || c > '9') return (NO_PID); p = 10 * p + (c - '0'); if (p > PID_MAX) return (NO_PID); } return (p); } /* * procfs vnode operations. */ int (**procfs_vnodeop_p)(); struct vnodeopv_entry_desc procfs_vnodeop_entries[] = { { &vop_default_desc, vn_default_error }, { &vop_lookup_desc, procfs_lookup }, /* lookup */ { &vop_create_desc, procfs_create }, /* create */ { &vop_mknod_desc, procfs_mknod }, /* mknod */ { &vop_open_desc, procfs_open }, /* open */ { &vop_close_desc, procfs_close }, /* close */ { &vop_access_desc, procfs_access }, /* access */ { &vop_getattr_desc, procfs_getattr }, /* getattr */ { &vop_setattr_desc, procfs_setattr }, /* setattr */ { &vop_read_desc, procfs_read }, /* read */ { &vop_write_desc, procfs_write }, /* write */ { &vop_ioctl_desc, procfs_ioctl }, /* ioctl */ { &vop_select_desc, procfs_select }, /* select */ { &vop_mmap_desc, procfs_mmap }, /* mmap */ { &vop_fsync_desc, procfs_fsync }, /* fsync */ { &vop_seek_desc, procfs_seek }, /* seek */ { &vop_remove_desc, procfs_remove }, /* remove */ { &vop_link_desc, procfs_link }, /* link */ { &vop_rename_desc, procfs_rename }, /* rename */ { &vop_mkdir_desc, procfs_mkdir }, /* mkdir */ { &vop_rmdir_desc, procfs_rmdir }, /* rmdir */ { &vop_symlink_desc, procfs_symlink }, /* symlink */ { &vop_readdir_desc, procfs_readdir }, /* readdir */ { &vop_readlink_desc, procfs_readlink }, /* readlink */ { &vop_abortop_desc, procfs_abortop }, /* abortop */ { &vop_inactive_desc, procfs_inactive }, /* inactive */ { &vop_reclaim_desc, procfs_reclaim }, /* reclaim */ { &vop_lock_desc, procfs_lock }, /* lock */ { &vop_unlock_desc, procfs_unlock }, /* unlock */ { &vop_bmap_desc, procfs_bmap }, /* bmap */ { &vop_strategy_desc, procfs_strategy }, /* strategy */ { &vop_print_desc, procfs_print }, /* print */ { &vop_islocked_desc, procfs_islocked }, /* islocked */ { &vop_pathconf_desc, procfs_pathconf }, /* pathconf */ { &vop_advlock_desc, procfs_advlock }, /* advlock */ { &vop_blkatoff_desc, procfs_blkatoff }, /* blkatoff */ { &vop_valloc_desc, procfs_valloc }, /* valloc */ { &vop_vfree_desc, procfs_vfree }, /* vfree */ { &vop_truncate_desc, procfs_truncate }, /* truncate */ { &vop_update_desc, procfs_update }, /* update */ { (struct vnodeop_desc*)NULL, (int(*)())NULL } }; struct vnodeopv_desc procfs_vnodeop_opv_desc = { &procfs_vnodeop_p, procfs_vnodeop_entries }; VNODEOP_SET(procfs_vnodeop_opv_desc);