Commit | Line | Data |
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e6aa77eb | 1 | /* vfs_vnops.c 4.2 %G% */ |
fc96c615 BJ |
2 | |
3 | #include "../h/param.h" | |
4 | #include "../h/systm.h" | |
5 | #include "../h/dir.h" | |
6 | #include "../h/user.h" | |
7 | #include "../h/filsys.h" | |
8 | #include "../h/file.h" | |
9 | #include "../h/conf.h" | |
10 | #include "../h/inode.h" | |
11 | #include "../h/reg.h" | |
12 | #include "../h/acct.h" | |
13 | ||
14 | /* | |
15 | * Convert a user supplied | |
16 | * file descriptor into a pointer | |
17 | * to a file structure. | |
18 | * Only task is to check range | |
19 | * of the descriptor. | |
20 | */ | |
21 | struct file * | |
22 | getf(f) | |
23 | register int f; | |
24 | { | |
25 | register struct file *fp; | |
26 | ||
27 | if(0 <= f && f < NOFILE) { | |
28 | fp = u.u_ofile[f]; | |
29 | if(fp != NULL) | |
30 | return(fp); | |
31 | } | |
32 | u.u_error = EBADF; | |
33 | return(NULL); | |
34 | } | |
35 | ||
36 | /* | |
37 | * Internal form of close. | |
38 | * Decrement reference count on | |
39 | * file structure. | |
40 | * Also make sure the pipe protocol | |
41 | * does not constipate. | |
42 | * | |
43 | * Decrement reference count on the inode following | |
44 | * removal to the referencing file structure. | |
45 | * Call device handler on last close. | |
46 | */ | |
47 | closef(fp) | |
48 | register struct file *fp; | |
49 | { | |
50 | register struct inode *ip; | |
51 | int flag, mode; | |
52 | dev_t dev; | |
53 | register int (*cfunc)(); | |
fc96c615 BJ |
54 | |
55 | if(fp == NULL) | |
56 | return; | |
57 | if (fp->f_count > 1) { | |
58 | fp->f_count--; | |
59 | return; | |
60 | } | |
61 | ip = fp->f_inode; | |
62 | flag = fp->f_flag; | |
fc96c615 BJ |
63 | dev = (dev_t)ip->i_un.i_rdev; |
64 | mode = ip->i_mode; | |
65 | ||
66 | plock(ip); | |
67 | fp->f_count = 0; | |
68 | if(flag & FPIPE) { | |
69 | ip->i_mode &= ~(IREAD|IWRITE); | |
70 | wakeup((caddr_t)ip+1); | |
71 | wakeup((caddr_t)ip+2); | |
72 | } | |
73 | iput(ip); | |
74 | ||
75 | switch(mode&IFMT) { | |
76 | ||
77 | case IFCHR: | |
78 | case IFMPC: | |
79 | cfunc = cdevsw[major(dev)].d_close; | |
80 | break; | |
81 | ||
82 | case IFBLK: | |
83 | case IFMPB: | |
84 | cfunc = bdevsw[major(dev)].d_close; | |
85 | break; | |
86 | default: | |
87 | return; | |
88 | } | |
89 | ||
90 | if (flag & FMP) | |
91 | goto call; | |
92 | ||
93 | for(fp=file; fp < &file[NFILE]; fp++) | |
36a4b8e3 BJ |
94 | if (fp->f_count && (ip=fp->f_inode)->i_un.i_rdev==dev && |
95 | (ip->i_mode&IFMT) == (mode&IFMT)) | |
fc96c615 BJ |
96 | return; |
97 | ||
98 | call: | |
e6aa77eb | 99 | (*cfunc)(dev, flag, fp); |
fc96c615 BJ |
100 | } |
101 | ||
102 | /* | |
103 | * openi called to allow handler | |
104 | * of special files to initialize and | |
105 | * validate before actual IO. | |
106 | */ | |
107 | openi(ip, rw) | |
108 | register struct inode *ip; | |
109 | { | |
110 | dev_t dev; | |
111 | register unsigned int maj; | |
112 | ||
113 | dev = (dev_t)ip->i_un.i_rdev; | |
114 | maj = major(dev); | |
115 | switch(ip->i_mode&IFMT) { | |
116 | ||
117 | case IFCHR: | |
118 | case IFMPC: | |
119 | if(maj >= nchrdev) | |
120 | goto bad; | |
121 | (*cdevsw[maj].d_open)(dev, rw); | |
122 | break; | |
123 | ||
124 | case IFBLK: | |
125 | case IFMPB: | |
126 | if(maj >= nblkdev) | |
127 | goto bad; | |
128 | (*bdevsw[maj].d_open)(dev, rw); | |
129 | } | |
130 | return; | |
131 | ||
132 | bad: | |
133 | u.u_error = ENXIO; | |
134 | } | |
135 | ||
136 | /* | |
137 | * Check mode permission on inode pointer. | |
138 | * Mode is READ, WRITE or EXEC. | |
139 | * In the case of WRITE, the | |
140 | * read-only status of the file | |
141 | * system is checked. | |
142 | * Also in WRITE, prototype text | |
143 | * segments cannot be written. | |
144 | * The mode is shifted to select | |
145 | * the owner/group/other fields. | |
146 | * The super user is granted all | |
147 | * permissions. | |
148 | */ | |
149 | access(ip, mode) | |
150 | register struct inode *ip; | |
151 | { | |
152 | register m; | |
153 | ||
154 | m = mode; | |
155 | if(m == IWRITE) { | |
156 | if(getfs(ip->i_dev)->s_ronly != 0) { | |
157 | u.u_error = EROFS; | |
158 | return(1); | |
159 | } | |
160 | if (ip->i_flag&ITEXT) /* try to free text */ | |
161 | xrele(ip); | |
162 | if(ip->i_flag & ITEXT) { | |
163 | u.u_error = ETXTBSY; | |
164 | return(1); | |
165 | } | |
166 | } | |
167 | if(u.u_uid == 0) | |
168 | return(0); | |
169 | if(u.u_uid != ip->i_uid) { | |
170 | m >>= 3; | |
171 | if(u.u_gid != ip->i_gid) | |
172 | m >>= 3; | |
173 | } | |
174 | if((ip->i_mode&m) != 0) | |
175 | return(0); | |
176 | ||
177 | u.u_error = EACCES; | |
178 | return(1); | |
179 | } | |
180 | ||
181 | /* | |
182 | * Look up a pathname and test if | |
183 | * the resultant inode is owned by the | |
184 | * current user. | |
185 | * If not, try for super-user. | |
186 | * If permission is granted, | |
187 | * return inode pointer. | |
188 | */ | |
189 | struct inode * | |
190 | owner() | |
191 | { | |
192 | register struct inode *ip; | |
193 | ||
194 | ip = namei(uchar, 0); | |
195 | if(ip == NULL) | |
196 | return(NULL); | |
197 | if(u.u_uid == ip->i_uid) | |
198 | return(ip); | |
199 | if(suser()) | |
200 | return(ip); | |
201 | iput(ip); | |
202 | return(NULL); | |
203 | } | |
204 | ||
205 | /* | |
206 | * Test if the current user is the | |
207 | * super user. | |
208 | */ | |
209 | suser() | |
210 | { | |
211 | ||
212 | if(u.u_uid == 0) { | |
213 | u.u_acflag |= ASU; | |
214 | return(1); | |
215 | } | |
216 | u.u_error = EPERM; | |
217 | return(0); | |
218 | } | |
219 | ||
220 | /* | |
221 | * Allocate a user file descriptor. | |
222 | */ | |
223 | ufalloc() | |
224 | { | |
225 | register i; | |
226 | ||
227 | for(i=0; i<NOFILE; i++) | |
228 | if(u.u_ofile[i] == NULL) { | |
229 | u.u_r.r_val1 = i; | |
230 | u.u_pofile[i] = 0; | |
231 | return(i); | |
232 | } | |
233 | u.u_error = EMFILE; | |
234 | return(-1); | |
235 | } | |
236 | ||
9c98386a | 237 | struct file *lastf = &file[0]; |
fc96c615 BJ |
238 | /* |
239 | * Allocate a user file descriptor | |
240 | * and a file structure. | |
241 | * Initialize the descriptor | |
242 | * to point at the file structure. | |
243 | * | |
244 | * no file -- if there are no available | |
245 | * file structures. | |
246 | */ | |
247 | struct file * | |
248 | falloc() | |
249 | { | |
250 | register struct file *fp; | |
251 | register i; | |
252 | ||
253 | i = ufalloc(); | |
254 | if(i < 0) | |
255 | return(NULL); | |
9c98386a BJ |
256 | for(fp = lastf; fp < &file[NFILE]; fp++) |
257 | if(fp->f_count == 0) | |
258 | goto slot; | |
259 | for(fp = &file[0]; fp < lastf; fp++) | |
260 | if(fp->f_count == 0) | |
261 | goto slot; | |
fc96c615 BJ |
262 | printf("no file\n"); |
263 | u.u_error = ENFILE; | |
264 | return(NULL); | |
9c98386a BJ |
265 | slot: |
266 | u.u_ofile[i] = fp; | |
267 | fp->f_count++; | |
268 | fp->f_un.f_offset = 0; | |
269 | lastf = fp + 1; | |
270 | return(fp); | |
fc96c615 | 271 | } |