xref: /titanic_41/usr/src/uts/common/syscall/open.c (revision 9c9af2590af49bb395bc8d2eace0f2d4ea16d165)
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 2008 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 #include <sys/param.h>
35 #include <sys/isa_defs.h>
36 #include <sys/types.h>
37 #include <sys/sysmacros.h>
38 #include <sys/user.h>
39 #include <sys/systm.h>
40 #include <sys/errno.h>
41 #include <sys/fcntl.h>
42 #include <sys/stat.h>
43 #include <sys/vnode.h>
44 #include <sys/vfs.h>
45 #include <sys/file.h>
46 #include <sys/mode.h>
47 #include <sys/uio.h>
48 #include <sys/debug.h>
49 #include <c2/audit.h>
50 #include <sys/cmn_err.h>
51 
52 /*
53  * Common code for open()/openat() and creat().  Check permissions, allocate
54  * an open file structure, and call the device open routine (if any).
55  */
56 
57 static int
58 copen(int startfd, char *fname, int filemode, int createmode)
59 {
60 	struct pathname pn;
61 	vnode_t *vp, *sdvp;
62 	file_t *fp, *startfp;
63 	enum vtype type;
64 	int error;
65 	int fd, dupfd;
66 	vnode_t *startvp;
67 	proc_t *p = curproc;
68 	uio_seg_t seg = UIO_USERSPACE;
69 	char *open_filename = fname;
70 
71 	if (startfd == AT_FDCWD) {
72 		/*
73 		 * Regular open()
74 		 */
75 		startvp = NULL;
76 	} else {
77 		/*
78 		 * We're here via openat()
79 		 */
80 		char startchar;
81 
82 		if (copyin(fname, &startchar, sizeof (char)))
83 			return (set_errno(EFAULT));
84 
85 		/*
86 		 * if startchar is / then startfd is ignored
87 		 */
88 		if (startchar == '/')
89 			startvp = NULL;
90 		else {
91 			if ((startfp = getf(startfd)) == NULL)
92 				return (set_errno(EBADF));
93 			startvp = startfp->f_vnode;
94 			VN_HOLD(startvp);
95 			releasef(startfd);
96 		}
97 	}
98 
99 	/*
100 	 * Handle openattrdirat request
101 	 */
102 	if (filemode & FXATTRDIROPEN) {
103 			if (audit_active)
104 				audit_setfsat_path(1);
105 
106 		if (error = lookupnameat(fname, seg, FOLLOW,
107 		    NULLVPP, &vp, startvp))
108 			return (set_errno(error));
109 		if (startvp) {
110 			VN_RELE(startvp);
111 			startvp = NULL;
112 		}
113 
114 		startvp = vp;
115 	}
116 
117 	/*
118 	 * Do we need to go into extended attribute space?
119 	 */
120 	if (filemode & (FXATTR|FXATTRDIROPEN)) {
121 		vattr_t vattr;
122 
123 		/*
124 		 * Make sure we have a valid request.
125 		 * We must either have a real fd or AT_FDCWD
126 		 */
127 
128 		if (startfd != AT_FDCWD && startvp == NULL) {
129 			error = EINVAL;
130 			goto out;
131 		}
132 
133 		if (error = pn_get(fname, UIO_USERSPACE, &pn)) {
134 			goto out;
135 		}
136 
137 		if (startfd == AT_FDCWD && !(filemode & FXATTRDIROPEN)) {
138 			mutex_enter(&p->p_lock);
139 			startvp = PTOU(p)->u_cdir;
140 			VN_HOLD(startvp);
141 			mutex_exit(&p->p_lock);
142 		}
143 
144 		/*
145 		 * In order to access hidden attribute directory the
146 		 * user must be able to stat() the file
147 		 */
148 
149 		vattr.va_mask = AT_ALL;
150 		if (error = VOP_GETATTR(startvp, &vattr, 0, CRED(), NULL)) {
151 			pn_free(&pn);
152 			goto out;
153 		}
154 
155 		if ((startvp->v_vfsp->vfs_flag & VFS_XATTR) != 0 ||
156 		    vfs_has_feature(startvp->v_vfsp, VFSFT_SYSATTR_VIEWS)) {
157 			error = VOP_LOOKUP(startvp, "", &sdvp, &pn,
158 			    (filemode & FXATTRDIROPEN) ? LOOKUP_XATTR :
159 			    LOOKUP_XATTR|CREATE_XATTR_DIR, rootvp, CRED(),
160 			    NULL, NULL, NULL);
161 		} else {
162 			error = EINVAL;
163 		}
164 
165 		/*
166 		 * For openattrdirat use "." as filename to open
167 		 * as part of vn_openat()
168 		 */
169 		if (error == 0 && (filemode & FXATTRDIROPEN)) {
170 			open_filename = ".";
171 			seg = UIO_SYSSPACE;
172 		}
173 
174 		pn_free(&pn);
175 		if (error != 0)
176 			goto out;
177 
178 		VN_RELE(startvp);
179 		startvp = sdvp;
180 	}
181 
182 	if ((filemode & (FREAD|FWRITE|FXATTRDIROPEN)) != 0) {
183 		if ((filemode & (FNONBLOCK|FNDELAY)) == (FNONBLOCK|FNDELAY))
184 			filemode &= ~FNDELAY;
185 		error = falloc((vnode_t *)NULL, filemode, &fp, &fd);
186 		if (error == 0) {
187 			if (audit_active)
188 				audit_setfsat_path(1);
189 			/*
190 			 * Last arg is a don't-care term if
191 			 * !(filemode & FCREAT).
192 			 */
193 
194 			error = vn_openat(open_filename, seg, filemode,
195 			    (int)(createmode & MODEMASK),
196 			    &vp, CRCREAT, PTOU(curproc)->u_cmask,
197 			    startvp, fd);
198 
199 			if (startvp != NULL)
200 				VN_RELE(startvp);
201 			if (error == 0) {
202 				if (audit_active)
203 					audit_copen(fd, fp, vp);
204 				if ((vp->v_flag & VDUP) == 0) {
205 					fp->f_vnode = vp;
206 					mutex_exit(&fp->f_tlock);
207 					/*
208 					 * We must now fill in the slot
209 					 * falloc reserved.
210 					 */
211 					setf(fd, fp);
212 					return (fd);
213 				} else {
214 					/*
215 					 * Special handling for /dev/fd.
216 					 * Give up the file pointer
217 					 * and dup the indicated file descriptor
218 					 * (in v_rdev). This is ugly, but I've
219 					 * seen worse.
220 					 */
221 					unfalloc(fp);
222 					dupfd = getminor(vp->v_rdev);
223 					type = vp->v_type;
224 					mutex_enter(&vp->v_lock);
225 					vp->v_flag &= ~VDUP;
226 					mutex_exit(&vp->v_lock);
227 					VN_RELE(vp);
228 					if (type != VCHR)
229 						return (set_errno(EINVAL));
230 					if ((fp = getf(dupfd)) == NULL) {
231 						setf(fd, NULL);
232 						return (set_errno(EBADF));
233 					}
234 					mutex_enter(&fp->f_tlock);
235 					fp->f_count++;
236 					mutex_exit(&fp->f_tlock);
237 					setf(fd, fp);
238 					releasef(dupfd);
239 				}
240 				return (fd);
241 			} else {
242 				setf(fd, NULL);
243 				unfalloc(fp);
244 				return (set_errno(error));
245 			}
246 		}
247 	} else {
248 		error = EINVAL;
249 	}
250 out:
251 	if (startvp != NULL)
252 		VN_RELE(startvp);
253 	return (set_errno(error));
254 }
255 
256 #define	OPENMODE32(fmode)	((int)((fmode)-FOPEN))
257 #define	CREATMODE32		(FWRITE|FCREAT|FTRUNC)
258 #define	OPENMODE64(fmode)	(OPENMODE32(fmode) | FOFFMAX)
259 #define	OPENMODEATTRDIR		FXATTRDIROPEN
260 #define	CREATMODE64		(CREATMODE32 | FOFFMAX)
261 #ifdef _LP64
262 #define	OPENMODE(fmode)		OPENMODE64(fmode)
263 #define	CREATMODE		CREATMODE64
264 #else
265 #define	OPENMODE		OPENMODE32
266 #define	CREATMODE		CREATMODE32
267 #endif
268 
269 /*
270  * Open a file.
271  */
272 int
273 open(char *fname, int fmode, int cmode)
274 {
275 	return (copen(AT_FDCWD, fname, OPENMODE(fmode), cmode));
276 }
277 
278 /*
279  * Create a file.
280  */
281 int
282 creat(char *fname, int cmode)
283 {
284 	return (copen(AT_FDCWD, fname, CREATMODE, cmode));
285 }
286 
287 int
288 openat(int fd, char *path, int fmode, int cmode)
289 {
290 	return (copen(fd, path, OPENMODE(fmode), cmode));
291 }
292 
293 #if defined(_ILP32) || defined(_SYSCALL32_IMPL)
294 /*
295  * Open and Creat for large files in 32-bit environment. Sets the FOFFMAX flag.
296  */
297 int
298 open64(char *fname, int fmode, int cmode)
299 {
300 	return (copen(AT_FDCWD, fname, OPENMODE64(fmode), cmode));
301 }
302 
303 int
304 creat64(char *fname, int cmode)
305 {
306 	return (copen(AT_FDCWD, fname, CREATMODE64, cmode));
307 }
308 
309 int
310 openat64(int fd, char *path, int fmode, int cmode)
311 {
312 	return (copen(fd, path, OPENMODE64(fmode), cmode));
313 }
314 
315 #endif	/* _ILP32 || _SYSCALL32_IMPL */
316 
317 #ifdef _SYSCALL32_IMPL
318 /*
319  * Open and Creat for 32-bit compatibility on 64-bit kernel
320  */
321 int
322 open32(char *fname, int fmode, int cmode)
323 {
324 	return (copen(AT_FDCWD, fname, OPENMODE32(fmode), cmode));
325 }
326 
327 int
328 creat32(char *fname, int cmode)
329 {
330 	return (copen(AT_FDCWD, fname, CREATMODE32, cmode));
331 }
332 
333 int
334 openat32(int fd, char *path, int fmode, int cmode)
335 {
336 	return (copen(fd, path, OPENMODE32(fmode), cmode));
337 }
338 
339 #endif	/* _SYSCALL32_IMPL */
340 
341 /*
342  * Special interface to open hidden attribute directory.
343  */
344 int
345 openattrdirat(int fd, char *fname)
346 {
347 	return (copen(fd, fname, OPENMODEATTRDIR, 0));
348 }
349