xref: /titanic_51/usr/src/uts/common/syscall/open.c (revision 61dc244f52b4962ea505abec7e6cbade980d3c53)
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  * 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 
51 /*
52  * Common code for openat().  Check permissions, allocate an open
53  * file structure, and call the device open routine (if any).
54  */
55 
56 static int
57 copen(int startfd, char *fname, int filemode, int createmode)
58 {
59 	struct pathname pn;
60 	vnode_t *vp, *sdvp;
61 	file_t *fp, *startfp;
62 	enum vtype type;
63 	int error;
64 	int fd, dupfd;
65 	vnode_t *startvp;
66 	proc_t *p = curproc;
67 	uio_seg_t seg = UIO_USERSPACE;
68 	char *open_filename = fname;
69 	uint32_t auditing = AU_AUDITING();
70 	char startchar;
71 
72 	if (filemode & (FSEARCH|FEXEC)) {
73 		/*
74 		 * Must be one or the other and neither FREAD nor FWRITE
75 		 * Must not be any of FAPPEND FCREAT FTRUNC FXATTR FXATTRDIROPEN
76 		 * XXX: Should these just be silently ignored?
77 		 */
78 		if ((filemode & (FREAD|FWRITE)) ||
79 		    (filemode & (FSEARCH|FEXEC)) == (FSEARCH|FEXEC) ||
80 		    (filemode & (FAPPEND|FCREAT|FTRUNC|FXATTR|FXATTRDIROPEN)))
81 			return (set_errno(EINVAL));
82 	}
83 
84 	if (startfd == AT_FDCWD) {
85 		/*
86 		 * Regular open()
87 		 */
88 		startvp = NULL;
89 	} else {
90 		/*
91 		 * We're here via openat()
92 		 */
93 		if (copyin(fname, &startchar, sizeof (char)))
94 			return (set_errno(EFAULT));
95 
96 		/*
97 		 * if startchar is / then startfd is ignored
98 		 */
99 		if (startchar == '/')
100 			startvp = NULL;
101 		else {
102 			if ((startfp = getf(startfd)) == NULL)
103 				return (set_errno(EBADF));
104 			startvp = startfp->f_vnode;
105 			VN_HOLD(startvp);
106 			releasef(startfd);
107 		}
108 	}
109 
110 	/*
111 	 * Handle __openattrdirat() requests
112 	 */
113 	if (filemode & FXATTRDIROPEN) {
114 		if (auditing && startvp != NULL)
115 			audit_setfsat_path(1);
116 		if (error = lookupnameat(fname, seg, FOLLOW,
117 		    NULLVPP, &vp, startvp))
118 			return (set_errno(error));
119 		if (startvp != NULL)
120 			VN_RELE(startvp);
121 
122 		startvp = vp;
123 	}
124 
125 	/*
126 	 * Do we need to go into extended attribute space?
127 	 */
128 	if (filemode & FXATTR) {
129 		if (startfd == AT_FDCWD) {
130 			if (copyin(fname, &startchar, sizeof (char)))
131 				return (set_errno(EFAULT));
132 
133 			/*
134 			 * If startchar == '/' then no extended attributes
135 			 * are looked up.
136 			 */
137 			if (startchar == '/') {
138 				startvp = NULL;
139 			} else {
140 				mutex_enter(&p->p_lock);
141 				startvp = PTOU(p)->u_cdir;
142 				VN_HOLD(startvp);
143 				mutex_exit(&p->p_lock);
144 			}
145 		}
146 
147 		/*
148 		 * Make sure we have a valid extended attribute request.
149 		 * We must either have a real fd or AT_FDCWD and a relative
150 		 * pathname.
151 		 */
152 		if (startvp == NULL) {
153 			goto noxattr;
154 		}
155 	}
156 
157 	if (filemode & (FXATTR|FXATTRDIROPEN)) {
158 		vattr_t vattr;
159 
160 		if (error = pn_get(fname, UIO_USERSPACE, &pn)) {
161 			goto out;
162 		}
163 
164 		/*
165 		 * In order to access hidden attribute directory the
166 		 * user must be able to stat() the file
167 		 */
168 		vattr.va_mask = AT_ALL;
169 		if (error = VOP_GETATTR(startvp, &vattr, 0, CRED(), NULL)) {
170 			pn_free(&pn);
171 			goto out;
172 		}
173 
174 		if ((startvp->v_vfsp->vfs_flag & VFS_XATTR) != 0 ||
175 		    vfs_has_feature(startvp->v_vfsp, VFSFT_SYSATTR_VIEWS)) {
176 			error = VOP_LOOKUP(startvp, "", &sdvp, &pn,
177 			    (filemode & FXATTRDIROPEN) ? LOOKUP_XATTR :
178 			    LOOKUP_XATTR|CREATE_XATTR_DIR, rootvp, CRED(),
179 			    NULL, NULL, NULL);
180 		} else {
181 			error = EINVAL;
182 		}
183 
184 		/*
185 		 * For __openattrdirat() use "." as filename to open
186 		 * as part of vn_openat()
187 		 */
188 		if (error == 0 && (filemode & FXATTRDIROPEN)) {
189 			open_filename = ".";
190 			seg = UIO_SYSSPACE;
191 		}
192 
193 		pn_free(&pn);
194 		if (error != 0)
195 			goto out;
196 
197 		VN_RELE(startvp);
198 		startvp = sdvp;
199 	}
200 
201 noxattr:
202 	if ((filemode & (FREAD|FWRITE|FSEARCH|FEXEC|FXATTRDIROPEN)) != 0) {
203 		if ((filemode & (FNONBLOCK|FNDELAY)) == (FNONBLOCK|FNDELAY))
204 			filemode &= ~FNDELAY;
205 		error = falloc((vnode_t *)NULL, filemode, &fp, &fd);
206 		if (error == 0) {
207 			if (auditing && startvp != NULL)
208 				audit_setfsat_path(1);
209 			/*
210 			 * Last arg is a don't-care term if
211 			 * !(filemode & FCREAT).
212 			 */
213 			error = vn_openat(open_filename, seg, filemode,
214 			    (int)(createmode & MODEMASK),
215 			    &vp, CRCREAT, PTOU(curproc)->u_cmask,
216 			    startvp, fd);
217 
218 			if (startvp != NULL)
219 				VN_RELE(startvp);
220 			if (error == 0) {
221 				if ((vp->v_flag & VDUP) == 0) {
222 					fp->f_vnode = vp;
223 					mutex_exit(&fp->f_tlock);
224 					/*
225 					 * We must now fill in the slot
226 					 * falloc reserved.
227 					 */
228 					setf(fd, fp);
229 					return (fd);
230 				} else {
231 					/*
232 					 * Special handling for /dev/fd.
233 					 * Give up the file pointer
234 					 * and dup the indicated file descriptor
235 					 * (in v_rdev). This is ugly, but I've
236 					 * seen worse.
237 					 */
238 					unfalloc(fp);
239 					dupfd = getminor(vp->v_rdev);
240 					type = vp->v_type;
241 					mutex_enter(&vp->v_lock);
242 					vp->v_flag &= ~VDUP;
243 					mutex_exit(&vp->v_lock);
244 					VN_RELE(vp);
245 					if (type != VCHR)
246 						return (set_errno(EINVAL));
247 					if ((fp = getf(dupfd)) == NULL) {
248 						setf(fd, NULL);
249 						return (set_errno(EBADF));
250 					}
251 					mutex_enter(&fp->f_tlock);
252 					fp->f_count++;
253 					mutex_exit(&fp->f_tlock);
254 					setf(fd, fp);
255 					releasef(dupfd);
256 				}
257 				return (fd);
258 			} else {
259 				setf(fd, NULL);
260 				unfalloc(fp);
261 				return (set_errno(error));
262 			}
263 		}
264 	} else {
265 		error = EINVAL;
266 	}
267 out:
268 	if (startvp != NULL)
269 		VN_RELE(startvp);
270 	return (set_errno(error));
271 }
272 
273 #define	OPENMODE32(fmode)	(((fmode) & (FSEARCH | FEXEC))? \
274 				    (fmode) : (fmode) - FOPEN)
275 #define	OPENMODE64(fmode)	(OPENMODE32(fmode) | FOFFMAX)
276 #ifdef _LP64
277 #define	OPENMODE(fmode)		OPENMODE64(fmode)
278 #else
279 #define	OPENMODE(fmode)		OPENMODE32(fmode)
280 #endif
281 
282 /*
283  * Open a file.
284  */
285 int
286 openat(int fd, char *path, int fmode, int cmode)
287 {
288 	return (copen(fd, path, OPENMODE(fmode), cmode));
289 }
290 
291 int
292 open(char *path, int fmode, int cmode)
293 {
294 	return (openat(AT_FDCWD, path, fmode, cmode));
295 }
296 
297 #if defined(_ILP32) || defined(_SYSCALL32_IMPL)
298 /*
299  * Open for large files in 32-bit environment. Sets the FOFFMAX flag.
300  */
301 int
302 openat64(int fd, char *path, int fmode, int cmode)
303 {
304 	return (copen(fd, path, OPENMODE64(fmode), cmode));
305 }
306 
307 int
308 open64(char *path, int fmode, int cmode)
309 {
310 	return (openat64(AT_FDCWD, path, fmode, cmode));
311 }
312 
313 #endif	/* _ILP32 || _SYSCALL32_IMPL */
314 
315 #ifdef _SYSCALL32_IMPL
316 /*
317  * Open for 32-bit compatibility on 64-bit kernel
318  */
319 int
320 openat32(int fd, char *path, int fmode, int cmode)
321 {
322 	return (copen(fd, path, OPENMODE32(fmode), cmode));
323 }
324 
325 int
326 open32(char *path, int fmode, int cmode)
327 {
328 	return (openat32(AT_FDCWD, path, fmode, cmode));
329 }
330 
331 #endif	/* _SYSCALL32_IMPL */
332