xref: /illumos-gate/usr/src/uts/common/syscall/open.c (revision bb57d1f5164aca913cbd286ae1b61c896167cfa7)
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  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved  	*/
28 
29 /*
30  * Portions of this source code were derived from Berkeley 4.3 BSD
31  * under license from the Regents of the University of California.
32  */
33 
34 #pragma ident	"%Z%%M%	%I%	%E% SMI"
35 
36 #include <sys/param.h>
37 #include <sys/isa_defs.h>
38 #include <sys/types.h>
39 #include <sys/sysmacros.h>
40 #include <sys/user.h>
41 #include <sys/systm.h>
42 #include <sys/errno.h>
43 #include <sys/fcntl.h>
44 #include <sys/stat.h>
45 #include <sys/vnode.h>
46 #include <sys/vfs.h>
47 #include <sys/file.h>
48 #include <sys/mode.h>
49 #include <sys/uio.h>
50 #include <sys/debug.h>
51 #include <c2/audit.h>
52 #include <sys/cmn_err.h>
53 
54 /*
55  * Common code for open()/openat() and creat().  Check permissions, allocate
56  * an open 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 
73 	if (startfd == AT_FDCWD) {
74 		/*
75 		 * Regular open()
76 		 */
77 		startvp = NULL;
78 	} else {
79 		/*
80 		 * We're here via openat()
81 		 */
82 		char startchar;
83 
84 		if (copyin(fname, &startchar, sizeof (char)))
85 			return (set_errno(EFAULT));
86 
87 		/*
88 		 * if startchar is / then startfd is ignored
89 		 */
90 		if (startchar == '/')
91 			startvp = NULL;
92 		else {
93 			if ((startfp = getf(startfd)) == NULL)
94 				return (set_errno(EBADF));
95 			startvp = startfp->f_vnode;
96 			VN_HOLD(startvp);
97 			releasef(startfd);
98 		}
99 	}
100 
101 	/*
102 	 * Handle openattrdirat request
103 	 */
104 	if (filemode & FXATTRDIROPEN) {
105 #ifdef C2_AUDIT
106 			if (audit_active)
107 				audit_setfsat_path(1);
108 #endif /* C2_AUDIT */
109 
110 		if (error = lookupnameat(fname, seg, FOLLOW,
111 		    NULLVPP, &vp, startvp))
112 			return (set_errno(error));
113 		if (startvp) {
114 			VN_RELE(startvp);
115 			startvp = NULL;
116 		}
117 
118 		startvp = vp;
119 	}
120 
121 	/*
122 	 * Do we need to go into extended attribute space?
123 	 */
124 	if (filemode & (FXATTR|FXATTRDIROPEN)) {
125 		vattr_t vattr;
126 
127 		/*
128 		 * Make sure we have a valid request.
129 		 * We must either have a real fd or AT_FDCWD
130 		 */
131 
132 		if (startfd != AT_FDCWD && startvp == NULL) {
133 			error = EINVAL;
134 			goto out;
135 		}
136 
137 		if (error = pn_get(fname, UIO_USERSPACE, &pn)) {
138 			goto out;
139 		}
140 
141 		if (startfd == AT_FDCWD && !(filemode & FXATTRDIROPEN)) {
142 			mutex_enter(&p->p_lock);
143 			startvp = PTOU(p)->u_cdir;
144 			VN_HOLD(startvp);
145 			mutex_exit(&p->p_lock);
146 		}
147 
148 		/*
149 		 * In order to access hidden attribute directory the
150 		 * user must be able to stat() the file
151 		 */
152 
153 		vattr.va_mask = AT_ALL;
154 		if (error = VOP_GETATTR(startvp, &vattr, 0, CRED(), NULL)) {
155 			pn_free(&pn);
156 			goto out;
157 		}
158 
159 		if ((startvp->v_vfsp->vfs_flag & VFS_XATTR) != 0 ||
160 		    vfs_has_feature(startvp->v_vfsp, VFSFT_XVATTR)) {
161 			error = VOP_LOOKUP(startvp, "", &sdvp, &pn,
162 			    LOOKUP_XATTR|CREATE_XATTR_DIR, rootvp, CRED(),
163 			    NULL, NULL, NULL);
164 		} else {
165 			error = EINVAL;
166 		}
167 
168 		/*
169 		 * For openattrdirat use "." as filename to open
170 		 * as part of vn_openat()
171 		 */
172 		if (error == 0 && (filemode & FXATTRDIROPEN)) {
173 			open_filename = ".";
174 			seg = UIO_SYSSPACE;
175 		}
176 
177 		pn_free(&pn);
178 		if (error != 0)
179 			goto out;
180 
181 		VN_RELE(startvp);
182 		startvp = sdvp;
183 	}
184 
185 	if ((filemode & (FREAD|FWRITE|FXATTRDIROPEN)) != 0) {
186 		if ((filemode & (FNONBLOCK|FNDELAY)) == (FNONBLOCK|FNDELAY))
187 			filemode &= ~FNDELAY;
188 		error = falloc((vnode_t *)NULL, filemode, &fp, &fd);
189 		if (error == 0) {
190 #ifdef C2_AUDIT
191 			if (audit_active)
192 				audit_setfsat_path(1);
193 #endif /* C2_AUDIT */
194 			/*
195 			 * Last arg is a don't-care term if
196 			 * !(filemode & FCREAT).
197 			 */
198 
199 			error = vn_openat(open_filename, seg, filemode,
200 			    (int)(createmode & MODEMASK),
201 			    &vp, CRCREAT, PTOU(curproc)->u_cmask,
202 			    startvp, fd);
203 
204 			if (startvp != NULL)
205 				VN_RELE(startvp);
206 			if (error == 0) {
207 #ifdef C2_AUDIT
208 				if (audit_active)
209 					audit_copen(fd, fp, vp);
210 #endif /* C2_AUDIT */
211 				if ((vp->v_flag & VDUP) == 0) {
212 					fp->f_vnode = vp;
213 					mutex_exit(&fp->f_tlock);
214 					/*
215 					 * We must now fill in the slot
216 					 * falloc reserved.
217 					 */
218 					setf(fd, fp);
219 					return (fd);
220 				} else {
221 					/*
222 					 * Special handling for /dev/fd.
223 					 * Give up the file pointer
224 					 * and dup the indicated file descriptor
225 					 * (in v_rdev). This is ugly, but I've
226 					 * seen worse.
227 					 */
228 					unfalloc(fp);
229 					dupfd = getminor(vp->v_rdev);
230 					type = vp->v_type;
231 					mutex_enter(&vp->v_lock);
232 					vp->v_flag &= ~VDUP;
233 					mutex_exit(&vp->v_lock);
234 					VN_RELE(vp);
235 					if (type != VCHR)
236 						return (set_errno(EINVAL));
237 					if ((fp = getf(dupfd)) == NULL) {
238 						setf(fd, NULL);
239 						return (set_errno(EBADF));
240 					}
241 					mutex_enter(&fp->f_tlock);
242 					fp->f_count++;
243 					mutex_exit(&fp->f_tlock);
244 					setf(fd, fp);
245 					releasef(dupfd);
246 				}
247 				return (fd);
248 			} else {
249 				setf(fd, NULL);
250 				unfalloc(fp);
251 				return (set_errno(error));
252 			}
253 		}
254 	} else {
255 		error = EINVAL;
256 	}
257 out:
258 	if (startvp != NULL)
259 		VN_RELE(startvp);
260 	return (set_errno(error));
261 }
262 
263 #define	OPENMODE32(fmode)	((int)((fmode)-FOPEN))
264 #define	CREATMODE32		(FWRITE|FCREAT|FTRUNC)
265 #define	OPENMODE64(fmode)	(OPENMODE32(fmode) | FOFFMAX)
266 #define	OPENMODEATTRDIR		FXATTRDIROPEN
267 #define	CREATMODE64		(CREATMODE32 | FOFFMAX)
268 #ifdef _LP64
269 #define	OPENMODE(fmode)		OPENMODE64(fmode)
270 #define	CREATMODE		CREATMODE64
271 #else
272 #define	OPENMODE		OPENMODE32
273 #define	CREATMODE		CREATMODE32
274 #endif
275 
276 /*
277  * Open a file.
278  */
279 int
280 open(char *fname, int fmode, int cmode)
281 {
282 	return (copen(AT_FDCWD, fname, OPENMODE(fmode), cmode));
283 }
284 
285 /*
286  * Create a file.
287  */
288 int
289 creat(char *fname, int cmode)
290 {
291 	return (copen(AT_FDCWD, fname, CREATMODE, cmode));
292 }
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 #if defined(_ILP32) || defined(_SYSCALL32_IMPL)
301 /*
302  * Open and Creat for large files in 32-bit environment. Sets the FOFFMAX flag.
303  */
304 int
305 open64(char *fname, int fmode, int cmode)
306 {
307 	return (copen(AT_FDCWD, fname, OPENMODE64(fmode), cmode));
308 }
309 
310 int
311 creat64(char *fname, int cmode)
312 {
313 	return (copen(AT_FDCWD, fname, CREATMODE64, cmode));
314 }
315 
316 int
317 openat64(int fd, char *path, int fmode, int cmode)
318 {
319 	return (copen(fd, path, OPENMODE64(fmode), cmode));
320 }
321 
322 #endif	/* _ILP32 || _SYSCALL32_IMPL */
323 
324 #ifdef _SYSCALL32_IMPL
325 /*
326  * Open and Creat for 32-bit compatibility on 64-bit kernel
327  */
328 int
329 open32(char *fname, int fmode, int cmode)
330 {
331 	return (copen(AT_FDCWD, fname, OPENMODE32(fmode), cmode));
332 }
333 
334 int
335 creat32(char *fname, int cmode)
336 {
337 	return (copen(AT_FDCWD, fname, CREATMODE32, cmode));
338 }
339 
340 int
341 openat32(int fd, char *path, int fmode, int cmode)
342 {
343 	return (copen(fd, path, OPENMODE32(fmode), cmode));
344 }
345 
346 #endif	/* _SYSCALL32_IMPL */
347 
348 /*
349  * Special interface to open hidden attribute directory.
350  */
351 int
352 openattrdirat(int fd, char *fname)
353 {
354 	return (copen(fd, fname, OPENMODEATTRDIR, 0));
355 }
356