/* * Copyright (c) 1993, 1995 Jan-Simon Pendry * Copyright (c) 1993, 1995 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry. * * %sccs.include.redist.c% * * @(#)procfs_vnops.c 8.18 (Berkeley) 05/21/95 * * From: * $Id: procfs_vnops.c,v 3.2 1993/12/15 09:40:17 jsp Exp $ */ /* * procfs vnode interface */ #include #include #include #include #include #include #include #include #include #include #include #include /* for PAGE_SIZE */ #include #include /* * 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 */ struct proc_target { u_char pt_type; u_char pt_namlen; char *pt_name; pfstype pt_pfstype; int (*pt_valid) __P((struct proc *p)); } proc_targets[] = { #define N(s) sizeof(s)-1, s /* name type validp */ { DT_DIR, N("."), Pproc, NULL }, { DT_DIR, N(".."), Proot, NULL }, { DT_REG, N("file"), Pfile, procfs_validfile }, { DT_REG, N("mem"), Pmem, NULL }, { DT_REG, N("regs"), Pregs, procfs_validregs }, { DT_REG, N("fpregs"), Pfpregs, procfs_validfpregs }, { DT_REG, N("ctl"), Pctl, NULL }, { DT_REG, N("status"), Pstatus, NULL }, { DT_REG, N("note"), Pnote, NULL }, { DT_REG, N("notepg"), Pnotepg, NULL }, #undef N }; static int nproc_targets = sizeof(proc_targets) / sizeof(proc_targets[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. */ procfs_open(ap) struct vop_open_args /* { struct vnode *a_vp; int a_mode; struct ucred *a_cred; struct proc *a_p; } */ *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). */ procfs_close(ap) struct vop_close_args /* { struct vnode *a_vp; int a_fflag; struct ucred *a_cred; struct proc *a_p; } */ *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; } return (0); } /* * do an ioctl operation on pfsnode (vp). * (vp) is not locked on entry or exit. */ procfs_ioctl(ap) struct vop_ioctl_args /* { struct vnode *a_vp; int a_command; caddr_t a_data; int a_fflag; struct ucred *a_cred; struct proc *a_p; } */ *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. */ procfs_bmap(ap) struct vop_bmap_args /* { struct vnode *a_vp; daddr_t a_bn; struct vnode **a_vpp; daddr_t *a_bnp; int *a_runp; } */ *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); } /* * procfs_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 locked on entry, but must be unlocked on exit. */ procfs_inactive(ap) struct vop_inactive_args /* { struct vnode *a_vp; } */ *ap; { struct vnode *vp = ap->a_vp; struct pfsnode *pfs = VTOPFS(vp); VOP_UNLOCK(vp, 0, ap->a_p); if (PFIND(pfs->pfs_pid) == 0) vgone(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. */ procfs_reclaim(ap) struct vop_reclaim_args /* { struct vnode *a_vp; } */ *ap; { return (procfs_freevp(ap->a_vp)); } /* * Return POSIX pathconf information applicable to special devices. */ 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). */ procfs_print(ap) struct vop_print_args /* { struct vnode *a_vp; } */ *ap; { struct pfsnode *pfs = VTOPFS(ap->a_vp); printf("tag VT_PROCFS, type %s, pid %d, mode %x, flags %x\n", pfs->pfs_type, pfs->pfs_pid, pfs->pfs_mode, pfs->pfs_flags); } /* * _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. */ procfs_abortop(ap) struct vop_abortop_args /* { struct vnode *a_dvp; struct componentname *a_cnp; } */ *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 */ 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. */ procfs_getattr(ap) struct vop_getattr_args /* { struct vnode *a_vp; struct vattr *a_vap; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct pfsnode *pfs = VTOPFS(ap->a_vp); struct vattr *vap = ap->a_vap; struct proc *procp; struct timeval tv; int error; /* first check the process still exists */ switch (pfs->pfs_type) { case Proot: case Pcurproc: 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; /* * 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. */ microtime(&tv); TIMEVAL_TO_TIMESPEC(&tv, &vap->va_ctime); vap->va_atime = vap->va_mtime = vap->va_ctime; /* * 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 Pmem: case Pregs: case Pfpregs: if (procp->p_flag & P_SUGID) vap->va_mode &= ~((VREAD|VWRITE)| ((VREAD|VWRITE)>>3)| ((VREAD|VWRITE)>>6)); 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; } /* * 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: /* * Set nlink to 1 to tell fts(3) we don't actually know. */ vap->va_nlink = 1; vap->va_uid = 0; vap->va_gid = 0; vap->va_size = vap->va_bytes = DEV_BSIZE; break; case Pcurproc: { char buf[16]; /* should be enough */ vap->va_nlink = 1; vap->va_uid = 0; vap->va_gid = 0; vap->va_size = vap->va_bytes = sprintf(buf, "%ld", (long)curproc->p_pid); break; } case Pproc: vap->va_nlink = 2; vap->va_uid = procp->p_ucred->cr_uid; vap->va_gid = procp->p_ucred->cr_gid; vap->va_size = vap->va_bytes = DEV_BSIZE; break; case Pfile: error = EOPNOTSUPP; break; case Pmem: vap->va_bytes = vap->va_size = ctob(procp->p_vmspace->vm_tsize + procp->p_vmspace->vm_dsize + procp->p_vmspace->vm_ssize); break; case Pregs: vap->va_bytes = vap->va_size = sizeof(struct reg); break; case Pfpregs: vap->va_bytes = vap->va_size = sizeof(struct fpreg); break; case Pctl: case Pstatus: case Pnote: case Pnotepg: break; default: panic("procfs_getattr"); } return (error); } procfs_setattr(ap) struct vop_setattr_args /* { struct vnode *a_vp; struct vattr *a_vap; struct ucred *a_cred; struct proc *a_p; } */ *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. */ procfs_access(ap) struct vop_access_args /* { struct vnode *a_vp; int a_mode; struct ucred *a_cred; struct proc *a_p; } */ *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 == 0) return (0); vap = &vattr; if (error = VOP_GETATTR(ap->a_vp, vap, ap->a_cred, ap->a_p)) 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(). */ procfs_lookup(ap) struct vop_lookup_args /* { struct vnode * a_dvp; struct vnode ** a_vpp; struct componentname * a_cnp; } */ *ap; { struct componentname *cnp = ap->a_cnp; struct vnode **vpp = ap->a_vpp; struct vnode *dvp = ap->a_dvp; char *pname = cnp->cn_nameptr; struct proc *curp = cnp->cn_proc; int error = 0; struct proc_target *pt; struct vnode *fvp; pid_t pid; struct pfsnode *pfs; struct proc *p; int i; *vpp = NULL; if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) return (EROFS); if (cnp->cn_namelen == 1 && *pname == '.') { *vpp = dvp; VREF(dvp); /* vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, curp); */ return (0); } pfs = VTOPFS(dvp); switch (pfs->pfs_type) { case Proot: if (cnp->cn_flags & ISDOTDOT) return (EIO); if (CNEQ(cnp, "curproc", 7)) return (procfs_allocvp(dvp->v_mount, vpp, 0, Pcurproc)); pid = atopid(pname, cnp->cn_namelen); if (pid == NO_PID) break; p = PFIND(pid); if (p == 0) break; return (procfs_allocvp(dvp->v_mount, vpp, pid, Pproc)); case Pproc: if (cnp->cn_flags & ISDOTDOT) return (procfs_root(dvp->v_mount, vpp)); p = PFIND(pfs->pfs_pid); if (p == 0) break; for (pt = proc_targets, i = 0; i < nproc_targets; pt++, i++) { if (cnp->cn_namelen == pt->pt_namlen && bcmp(pt->pt_name, pname, cnp->cn_namelen) == 0 && (pt->pt_valid == NULL || (*pt->pt_valid)(p))) goto found; } break; found: if (pt->pt_pfstype == Pfile) { fvp = procfs_findtextvp(p); /* We already checked that it exists. */ VREF(fvp); vn_lock(fvp, LK_EXCLUSIVE | LK_RETRY, curp); *vpp = fvp; return (0); } return (procfs_allocvp(dvp->v_mount, vpp, pfs->pfs_pid, pt->pt_pfstype)); default: return (ENOTDIR); } return (cnp->cn_nameiop == LOOKUP ? ENOENT : EROFS); } int procfs_validfile(p) struct proc *p; { return (procfs_findtextvp(p) != NULLVP); } /* * 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() */ procfs_readdir(ap) struct vop_readdir_args /* { struct vnode *a_vp; struct uio *a_uio; struct ucred *a_cred; int *a_eofflag; u_long *a_cookies; int a_ncookies; } */ *ap; { struct uio *uio = ap->a_uio; struct pfsdent d; struct pfsdent *dp = &d; struct pfsnode *pfs; int error; int count; int i; /* * We don't allow exporting procfs mounts, and currently local * requests do not need cookies. */ if (ap->a_ncookies) panic("procfs_readdir: not hungry"); 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: { struct proc *p; struct proc_target *pt; p = PFIND(pfs->pfs_pid); if (p == NULL) break; for (pt = &proc_targets[i]; uio->uio_resid >= UIO_MX && i < nproc_targets; pt++, i++) { if (pt->pt_valid && (*pt->pt_valid)(p) == 0) continue; dp->d_reclen = UIO_MX; dp->d_fileno = PROCFS_FILENO(pfs->pfs_pid, pt->pt_pfstype); dp->d_namlen = pt->pt_namlen; bcopy(pt->pt_name, dp->d_name, pt->pt_namlen + 1); dp->d_type = pt->pt_type; if (error = uiomove((caddr_t)dp, UIO_MX, uio)) break; } 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: { #ifdef PROCFS_ZOMBIE int doingzomb = 0; #endif int pcnt = 0; volatile struct proc *p = allproc.lh_first; again: for (; p && uio->uio_resid >= UIO_MX; i++, pcnt++) { bzero((char *) dp, UIO_MX); dp->d_reclen = UIO_MX; switch (i) { case 0: /* `.' */ case 1: /* `..' */ dp->d_fileno = PROCFS_FILENO(0, Proot); dp->d_namlen = i + 1; bcopy("..", dp->d_name, dp->d_namlen); dp->d_name[i + 1] = '\0'; dp->d_type = DT_DIR; break; case 2: dp->d_fileno = PROCFS_FILENO(0, Pcurproc); dp->d_namlen = 7; bcopy("curproc", dp->d_name, 8); dp->d_type = DT_LNK; break; default: while (pcnt < i) { pcnt++; p = p->p_list.le_next; if (!p) goto done; } dp->d_fileno = PROCFS_FILENO(p->p_pid, Pproc); dp->d_namlen = sprintf(dp->d_name, "%ld", (long)p->p_pid); dp->d_type = DT_REG; p = p->p_list.le_next; break; } if (error = uiomove((caddr_t)dp, UIO_MX, uio)) break; } done: #ifdef PROCFS_ZOMBIE if (p == 0 && doingzomb == 0) { doingzomb = 1; p = zombproc.lh_first; goto again; } #endif break; } default: error = ENOTDIR; break; } uio->uio_offset = i * UIO_MX; return (error); } /* * readlink reads the link of `curproc' */ procfs_readlink(ap) struct vop_readlink_args *ap; { struct uio *uio = ap->a_uio; char buf[16]; /* should be enough */ int len; if (VTOPFS(ap->a_vp)->pfs_fileno != PROCFS_FILENO(0, Pcurproc)) return (EINVAL); len = sprintf(buf, "%ld", (long)curproc->p_pid); return (uiomove((caddr_t)buf, len, ap->a_uio)); } /* * 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_revoke_desc, procfs_revoke }, /* revoke */ { &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 };