diff options
Diffstat (limited to 'sys/compat/linux/linux_getcwd.c')
| -rw-r--r-- | sys/compat/linux/linux_getcwd.c | 413 |
1 files changed, 18 insertions, 395 deletions
diff --git a/sys/compat/linux/linux_getcwd.c b/sys/compat/linux/linux_getcwd.c index 7c0b9ba5fa92..ebcf97008bf7 100644 --- a/sys/compat/linux/linux_getcwd.c +++ b/sys/compat/linux/linux_getcwd.c @@ -2,11 +2,15 @@ /* $NetBSD: vfs_getcwd.c,v 1.3.2.3 1999/07/11 10:24:09 sommerfeld Exp $ */ /*- * Copyright (c) 1999 The NetBSD Foundation, Inc. + * Copyright (c) 2015 The FreeBSD Foundation * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Bill Sommerfeld. * + * Portions of this software were developed by Edward Tomasz Napierala + * under sponsorship from the FreeBSD Foundation. + * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: @@ -36,19 +40,9 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/systm.h> -#include <sys/namei.h> -#include <sys/filedesc.h> -#include <sys/kernel.h> -#include <sys/file.h> -#include <sys/stat.h> #include <sys/syscallsubr.h> -#include <sys/vnode.h> -#include <sys/mount.h> #include <sys/proc.h> -#include <sys/uio.h> #include <sys/malloc.h> -#include <sys/dirent.h> -#include <ufs/ufs/dir.h> /* XXX only for DIRBLKSIZ */ #ifdef COMPAT_LINUX32 #include <machine/../linux32/linux.h> @@ -60,408 +54,37 @@ __FBSDID("$FreeBSD$"); #include <compat/linux/linux_misc.h> #include <compat/linux/linux_util.h> -#include <security/mac/mac_framework.h> - -static int -linux_getcwd_scandir(struct vnode **, struct vnode **, - char **, char *, struct thread *); -static int -linux_getcwd_common(struct vnode *, struct vnode *, - char **, char *, int, int, struct thread *); - -#define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4) - -/* - * Vnode variable naming conventions in this file: - * - * rvp: the current root we're aiming towards. - * lvp, *lvpp: the "lower" vnode - * uvp, *uvpp: the "upper" vnode. - * - * Since all the vnodes we're dealing with are directories, and the - * lookups are going *up* in the filesystem rather than *down*, the - * usual "pvp" (parent) or "dvp" (directory) naming conventions are - * too confusing. - */ - -/* - * XXX Will infinite loop in certain cases if a directory read reliably - * returns EINVAL on last block. - * XXX is EINVAL the right thing to return if a directory is malformed? - */ - -/* - * XXX Untested vs. mount -o union; probably does the wrong thing. - */ - -/* - * Find parent vnode of *lvpp, return in *uvpp - * - * If we care about the name, scan it looking for name of directory - * entry pointing at lvp. - * - * Place the name in the buffer which starts at bufp, immediately - * before *bpp, and move bpp backwards to point at the start of it. - * - * On entry, *lvpp is a locked vnode reference; on exit, it is vput and NULL'ed - * On exit, *uvpp is either NULL or is a locked vnode reference. - */ -static int -linux_getcwd_scandir(lvpp, uvpp, bpp, bufp, td) - struct vnode **lvpp; - struct vnode **uvpp; - char **bpp; - char *bufp; - struct thread *td; -{ - int error = 0; - int eofflag; - off_t off; - int tries; - struct uio uio; - struct iovec iov; - char *dirbuf = NULL; - int dirbuflen; - ino_t fileno; - struct vattr va; - struct vnode *uvp = NULL; - struct vnode *lvp = *lvpp; - struct componentname cn; - int len, reclen; - tries = 0; - - /* - * If we want the filename, get some info we need while the - * current directory is still locked. - */ - if (bufp != NULL) { - error = VOP_GETATTR(lvp, &va, td->td_ucred); - if (error) { - vput(lvp); - *lvpp = NULL; - *uvpp = NULL; - return error; - } - } - - /* - * Ok, we have to do it the hard way.. - * Next, get parent vnode using lookup of .. - */ - cn.cn_nameiop = LOOKUP; - cn.cn_flags = ISLASTCN | ISDOTDOT | RDONLY; - cn.cn_thread = td; - cn.cn_cred = td->td_ucred; - cn.cn_pnbuf = NULL; - cn.cn_nameptr = ".."; - cn.cn_namelen = 2; - cn.cn_consume = 0; - cn.cn_lkflags = LK_SHARED; - - /* - * At this point, lvp is locked and will be unlocked by the lookup. - * On successful return, *uvpp will be locked - */ -#ifdef MAC - error = mac_vnode_check_lookup(td->td_ucred, lvp, &cn); - if (error == 0) -#endif - error = VOP_LOOKUP(lvp, uvpp, &cn); - if (error) { - vput(lvp); - *lvpp = NULL; - *uvpp = NULL; - return error; - } - uvp = *uvpp; - - /* If we don't care about the pathname, we're done */ - if (bufp == NULL) { - vput(lvp); - *lvpp = NULL; - return 0; - } - - fileno = va.va_fileid; - - dirbuflen = DIRBLKSIZ; - if (dirbuflen < va.va_blocksize) - dirbuflen = va.va_blocksize; - dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK); - -#if 0 -unionread: -#endif - off = 0; - do { - /* call VOP_READDIR of parent */ - iov.iov_base = dirbuf; - iov.iov_len = dirbuflen; - - uio.uio_iov = &iov; - uio.uio_iovcnt = 1; - uio.uio_offset = off; - uio.uio_resid = dirbuflen; - uio.uio_segflg = UIO_SYSSPACE; - uio.uio_rw = UIO_READ; - uio.uio_td = td; - - eofflag = 0; - -#ifdef MAC - error = mac_vnode_check_readdir(td->td_ucred, uvp); - if (error == 0) -#endif /* MAC */ - error = VOP_READDIR(uvp, &uio, td->td_ucred, &eofflag, - 0, 0); - - off = uio.uio_offset; - - /* - * Try again if NFS tosses its cookies. - * XXX this can still loop forever if the directory is busted - * such that the second or subsequent page of it always - * returns EINVAL - */ - if ((error == EINVAL) && (tries < 3)) { - off = 0; - tries++; - continue; /* once more, with feeling */ - } - - if (!error) { - char *cpos; - struct dirent *dp; - - cpos = dirbuf; - tries = 0; - - /* scan directory page looking for matching vnode */ - for (len = (dirbuflen - uio.uio_resid); len > 0; len -= reclen) { - dp = (struct dirent *) cpos; - reclen = dp->d_reclen; - - /* check for malformed directory.. */ - if (reclen < DIRENT_MINSIZE) { - error = EINVAL; - goto out; - } - /* - * XXX should perhaps do VOP_LOOKUP to - * check that we got back to the right place, - * but getting the locking games for that - * right would be heinous. - */ - if ((dp->d_type != DT_WHT) && - (dp->d_fileno == fileno)) { - char *bp = *bpp; - bp -= dp->d_namlen; - - if (bp <= bufp) { - error = ERANGE; - goto out; - } - bcopy(dp->d_name, bp, dp->d_namlen); - error = 0; - *bpp = bp; - goto out; - } - cpos += reclen; - } - } - } while (!eofflag); - error = ENOENT; - -out: - vput(lvp); - *lvpp = NULL; - free(dirbuf, M_TEMP); - return error; -} - - -/* - * common routine shared by sys___getcwd() and linux_vn_isunder() - */ - -#define GETCWD_CHECK_ACCESS 0x0001 - -static int -linux_getcwd_common (lvp, rvp, bpp, bufp, limit, flags, td) - struct vnode *lvp; - struct vnode *rvp; - char **bpp; - char *bufp; - int limit; - int flags; - struct thread *td; -{ - struct filedesc *fdp = td->td_proc->p_fd; - struct vnode *uvp = NULL; - char *bp = NULL; - int error; - accmode_t accmode = VEXEC; - - if (rvp == NULL) { - rvp = fdp->fd_rdir; - if (rvp == NULL) - rvp = rootvnode; - } - - VREF(rvp); - VREF(lvp); - - /* - * Error handling invariant: - * Before a `goto out': - * lvp is either NULL, or locked and held. - * uvp is either NULL, or locked and held. - */ - - error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY); - if (error != 0) - panic("vn_lock LK_RETRY returned error %d", error); - if (bufp) - bp = *bpp; - /* - * this loop will terminate when one of the following happens: - * - we hit the root - * - getdirentries or lookup fails - * - we run out of space in the buffer. - */ - if (lvp == rvp) { - if (bp) - *(--bp) = '/'; - goto out; - } - do { - if (lvp->v_type != VDIR) { - error = ENOTDIR; - goto out; - } - - /* - * access check here is optional, depending on - * whether or not caller cares. - */ - if (flags & GETCWD_CHECK_ACCESS) { - error = VOP_ACCESS(lvp, accmode, td->td_ucred, td); - if (error) - goto out; - accmode = VEXEC|VREAD; - } - - /* - * step up if we're a covered vnode.. - */ - while (lvp->v_vflag & VV_ROOT) { - struct vnode *tvp; - - if (lvp == rvp) - goto out; - - tvp = lvp; - lvp = lvp->v_mount->mnt_vnodecovered; - vput(tvp); - /* - * hodie natus est radici frater - */ - if (lvp == NULL) { - error = ENOENT; - goto out; - } - VREF(lvp); - error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY); - if (error != 0) - panic("vn_lock LK_RETRY returned %d", error); - } - error = linux_getcwd_scandir(&lvp, &uvp, &bp, bufp, td); - if (error) - goto out; -#ifdef DIAGNOSTIC - if (lvp != NULL) - panic("getcwd: oops, forgot to null lvp"); - if (bufp && (bp <= bufp)) { - panic("getcwd: oops, went back too far"); - } -#endif - if (bp) - *(--bp) = '/'; - lvp = uvp; - uvp = NULL; - limit--; - } while ((lvp != rvp) && (limit > 0)); - -out: - if (bpp) - *bpp = bp; - if (uvp) - vput(uvp); - if (lvp) - vput(lvp); - vrele(rvp); - return error; -} - - /* * Find pathname of process's current directory. - * - * Use vfs vnode-to-name reverse cache; if that fails, fall back - * to reading directory contents. */ - int linux_getcwd(struct thread *td, struct linux_getcwd_args *args) { - char *bp, *bend, *path; - int error, len, lenused; + char *path; + int error, lenused; #ifdef DEBUG if (ldebug(getcwd)) printf(ARGS(getcwd, "%p, %ld"), args->buf, (long)args->bufsize); #endif - len = args->bufsize; - - if (len > LINUX_PATH_MAX) - len = LINUX_PATH_MAX; - else if (len < 2) - return ERANGE; + /* + * Linux returns ERANGE instead of EINVAL. + */ + if (args->bufsize < 2) + return (ERANGE); - path = malloc(len, M_TEMP, M_WAITOK); + path = malloc(LINUX_PATH_MAX, M_TEMP, M_WAITOK); - error = kern___getcwd(td, path, UIO_SYSSPACE, len, LINUX_PATH_MAX); - if (!error) { + error = kern___getcwd(td, path, UIO_SYSSPACE, args->bufsize, + LINUX_PATH_MAX); + if (error == 0) { lenused = strlen(path) + 1; - if (lenused <= args->bufsize) { + error = copyout(path, args->buf, lenused); + if (error == 0) td->td_retval[0] = lenused; - error = copyout(path, args->buf, lenused); - } - else - error = ERANGE; - } else { - bp = &path[len]; - bend = bp; - *(--bp) = '\0'; - - /* - * 5th argument here is "max number of vnodes to traverse". - * Since each entry takes up at least 2 bytes in the output buffer, - * limit it to N/2 vnodes for an N byte buffer. - */ - - error = linux_getcwd_common (td->td_proc->p_fd->fd_cdir, NULL, - &bp, path, len/2, GETCWD_CHECK_ACCESS, td); - if (error) - goto out; - lenused = bend - bp; - td->td_retval[0] = lenused; - /* put the result into user buffer */ - error = copyout(bp, args->buf, lenused); } -out: + free(path, M_TEMP); return (error); } - |