xref: /illumos-gate/usr/src/uts/common/syscall/open.c (revision 05d57413)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
24  */
25 
26 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved  	*/
28 
29 /*
30  * Copyright (c) 2013, OmniTI Computer Consulting, Inc. All rights reserved.
31  */
32 /*
33  * Portions of this source code were derived from Berkeley 4.3 BSD
34  * under license from the Regents of the University of California.
35  */
36 
37 #include <sys/param.h>
38 #include <sys/isa_defs.h>
39 #include <sys/types.h>
40 #include <sys/sysmacros.h>
41 #include <sys/user.h>
42 #include <sys/systm.h>
43 #include <sys/errno.h>
44 #include <sys/fcntl.h>
45 #include <sys/stat.h>
46 #include <sys/vnode.h>
47 #include <sys/vfs.h>
48 #include <sys/file.h>
49 #include <sys/mode.h>
50 #include <sys/uio.h>
51 #include <sys/debug.h>
52 #include <c2/audit.h>
53 
54 /*
55  * Common code for openat().  Check permissions, allocate an open
56  * file structure, and call the device open routine (if any).
57  */
58 
59 static int
60 copen(int startfd, char *fname, int filemode, int createmode)
61 {
62 	struct pathname pn;
63 	vnode_t *vp, *sdvp;
64 	file_t *fp, *startfp;
65 	enum vtype type;
66 	int error;
67 	int fd, dupfd;
68 	vnode_t *startvp;
69 	proc_t *p = curproc;
70 	uio_seg_t seg = UIO_USERSPACE;
71 	char *open_filename = fname;
72 	uint32_t auditing = AU_AUDITING();
73 	char startchar;
74 
75 	if (filemode & (FSEARCH|FEXEC)) {
76 		/*
77 		 * Must be one or the other and neither FREAD nor FWRITE
78 		 * Must not be any of FAPPEND FCREAT FTRUNC FXATTR FXATTRDIROPEN
79 		 * XXX: Should these just be silently ignored?
80 		 */
81 		if ((filemode & (FREAD|FWRITE)) ||
82 		    (filemode & (FSEARCH|FEXEC)) == (FSEARCH|FEXEC) ||
83 		    (filemode & (FAPPEND|FCREAT|FTRUNC|FXATTR|FXATTRDIROPEN)))
84 			return (set_errno(EINVAL));
85 	}
86 
87 	if (startfd == AT_FDCWD) {
88 		/*
89 		 * Regular open()
90 		 */
91 		startvp = NULL;
92 	} else {
93 		/*
94 		 * We're here via openat()
95 		 */
96 		if (copyin(fname, &startchar, sizeof (char)))
97 			return (set_errno(EFAULT));
98 
99 		/*
100 		 * if startchar is / then startfd is ignored
101 		 */
102 		if (startchar == '/')
103 			startvp = NULL;
104 		else {
105 			if ((startfp = getf(startfd)) == NULL)
106 				return (set_errno(EBADF));
107 			startvp = startfp->f_vnode;
108 			VN_HOLD(startvp);
109 			releasef(startfd);
110 		}
111 	}
112 
113 	/*
114 	 * Handle __openattrdirat() requests
115 	 */
116 	if (filemode & FXATTRDIROPEN) {
117 		if (auditing && startvp != NULL)
118 			audit_setfsat_path(1);
119 		if (error = lookupnameat(fname, seg, FOLLOW,
120 		    NULLVPP, &vp, startvp))
121 			return (set_errno(error));
122 		if (startvp != NULL)
123 			VN_RELE(startvp);
124 
125 		startvp = vp;
126 	}
127 
128 	/*
129 	 * Do we need to go into extended attribute space?
130 	 */
131 	if (filemode & FXATTR) {
132 		if (startfd == AT_FDCWD) {
133 			if (copyin(fname, &startchar, sizeof (char)))
134 				return (set_errno(EFAULT));
135 
136 			/*
137 			 * If startchar == '/' then no extended attributes
138 			 * are looked up.
139 			 */
140 			if (startchar == '/') {
141 				startvp = NULL;
142 			} else {
143 				mutex_enter(&p->p_lock);
144 				startvp = PTOU(p)->u_cdir;
145 				VN_HOLD(startvp);
146 				mutex_exit(&p->p_lock);
147 			}
148 		}
149 
150 		/*
151 		 * Make sure we have a valid extended attribute request.
152 		 * We must either have a real fd or AT_FDCWD and a relative
153 		 * pathname.
154 		 */
155 		if (startvp == NULL) {
156 			goto noxattr;
157 		}
158 	}
159 
160 	if (filemode & (FXATTR|FXATTRDIROPEN)) {
161 		vattr_t vattr;
162 
163 		if (error = pn_get(fname, UIO_USERSPACE, &pn)) {
164 			goto out;
165 		}
166 
167 		/*
168 		 * In order to access hidden attribute directory the
169 		 * user must be able to stat() the file
170 		 */
171 		vattr.va_mask = AT_ALL;
172 		if (error = VOP_GETATTR(startvp, &vattr, 0, CRED(), NULL)) {
173 			pn_free(&pn);
174 			goto out;
175 		}
176 
177 		if ((startvp->v_vfsp->vfs_flag & VFS_XATTR) != 0 ||
178 		    vfs_has_feature(startvp->v_vfsp, VFSFT_SYSATTR_VIEWS)) {
179 			error = VOP_LOOKUP(startvp, "", &sdvp, &pn,
180 			    (filemode & FXATTRDIROPEN) ? LOOKUP_XATTR :
181 			    LOOKUP_XATTR|CREATE_XATTR_DIR, rootvp, CRED(),
182 			    NULL, NULL, NULL);
183 		} else {
184 			error = EINVAL;
185 		}
186 
187 		/*
188 		 * For __openattrdirat() use "." as filename to open
189 		 * as part of vn_openat()
190 		 */
191 		if (error == 0 && (filemode & FXATTRDIROPEN)) {
192 			open_filename = ".";
193 			seg = UIO_SYSSPACE;
194 		}
195 
196 		pn_free(&pn);
197 		if (error != 0)
198 			goto out;
199 
200 		VN_RELE(startvp);
201 		startvp = sdvp;
202 	}
203 
204 noxattr:
205 	if ((filemode & (FREAD|FWRITE|FSEARCH|FEXEC|FXATTRDIROPEN)) != 0) {
206 		if ((filemode & (FNONBLOCK|FNDELAY)) == (FNONBLOCK|FNDELAY))
207 			filemode &= ~FNDELAY;
208 		error = falloc((vnode_t *)NULL, filemode, &fp, &fd);
209 		if (error == 0) {
210 			if (auditing && startvp != NULL)
211 				audit_setfsat_path(1);
212 			/*
213 			 * Last arg is a don't-care term if
214 			 * !(filemode & FCREAT).
215 			 */
216 			error = vn_openat(open_filename, seg, filemode,
217 			    (int)(createmode & MODEMASK),
218 			    &vp, CRCREAT, PTOU(curproc)->u_cmask,
219 			    startvp, fd);
220 
221 			if (startvp != NULL)
222 				VN_RELE(startvp);
223 			if (error == 0) {
224 				if ((vp->v_flag & VDUP) == 0) {
225 					fp->f_vnode = vp;
226 					mutex_exit(&fp->f_tlock);
227 					/*
228 					 * We must now fill in the slot
229 					 * falloc reserved.
230 					 */
231 					setf(fd, fp);
232 					if ((filemode & FCLOEXEC) != 0) {
233 						f_setfd(fd, FD_CLOEXEC);
234 					}
235 					return (fd);
236 				} else {
237 					/*
238 					 * Special handling for /dev/fd.
239 					 * Give up the file pointer
240 					 * and dup the indicated file descriptor
241 					 * (in v_rdev). This is ugly, but I've
242 					 * seen worse.
243 					 */
244 					unfalloc(fp);
245 					dupfd = getminor(vp->v_rdev);
246 					type = vp->v_type;
247 					mutex_enter(&vp->v_lock);
248 					vp->v_flag &= ~VDUP;
249 					mutex_exit(&vp->v_lock);
250 					VN_RELE(vp);
251 					if (type != VCHR)
252 						return (set_errno(EINVAL));
253 					if ((fp = getf(dupfd)) == NULL) {
254 						setf(fd, NULL);
255 						return (set_errno(EBADF));
256 					}
257 					mutex_enter(&fp->f_tlock);
258 					fp->f_count++;
259 					mutex_exit(&fp->f_tlock);
260 					setf(fd, fp);
261 					if ((filemode & FCLOEXEC) != 0) {
262 						f_setfd(fd, FD_CLOEXEC);
263 					}
264 					releasef(dupfd);
265 				}
266 				return (fd);
267 			} else {
268 				setf(fd, NULL);
269 				unfalloc(fp);
270 				return (set_errno(error));
271 			}
272 		}
273 	} else {
274 		error = EINVAL;
275 	}
276 out:
277 	if (startvp != NULL)
278 		VN_RELE(startvp);
279 	return (set_errno(error));
280 }
281 
282 #define	OPENMODE32(fmode)	(((fmode) & (FSEARCH | FEXEC))? \
283 				    (fmode) : (fmode) - FOPEN)
284 #define	OPENMODE64(fmode)	(OPENMODE32(fmode) | FOFFMAX)
285 #ifdef _LP64
286 #define	OPENMODE(fmode)		OPENMODE64(fmode)
287 #else
288 #define	OPENMODE(fmode)		OPENMODE32(fmode)
289 #endif
290 
291 /*
292  * Open a file.
293  */
294 int
295 openat(int fd, char *path, int fmode, int cmode)
296 {
297 	return (copen(fd, path, OPENMODE(fmode), cmode));
298 }
299 
300 int
301 open(char *path, int fmode, int cmode)
302 {
303 	return (openat(AT_FDCWD, path, fmode, cmode));
304 }
305 
306 #if defined(_ILP32) || defined(_SYSCALL32_IMPL)
307 /*
308  * Open for large files in 32-bit environment. Sets the FOFFMAX flag.
309  */
310 int
311 openat64(int fd, char *path, int fmode, int cmode)
312 {
313 	return (copen(fd, path, OPENMODE64(fmode), cmode));
314 }
315 
316 int
317 open64(char *path, int fmode, int cmode)
318 {
319 	return (openat64(AT_FDCWD, path, fmode, cmode));
320 }
321 
322 #endif	/* _ILP32 || _SYSCALL32_IMPL */
323 
324 #ifdef _SYSCALL32_IMPL
325 /*
326  * Open for 32-bit compatibility on 64-bit kernel
327  */
328 int
329 openat32(int fd, char *path, int fmode, int cmode)
330 {
331 	return (copen(fd, path, OPENMODE32(fmode), cmode));
332 }
333 
334 int
335 open32(char *path, int fmode, int cmode)
336 {
337 	return (openat32(AT_FDCWD, path, fmode, cmode));
338 }
339 
340 #endif	/* _SYSCALL32_IMPL */
341