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fc96c615 BJ |
1 | /* vfs_vnops.c 3.1 %H% */ |
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)(); | |
54 | struct chan *cp; | |
55 | ||
56 | if(fp == NULL) | |
57 | return; | |
58 | if (fp->f_count > 1) { | |
59 | fp->f_count--; | |
60 | return; | |
61 | } | |
62 | ip = fp->f_inode; | |
63 | flag = fp->f_flag; | |
64 | cp = fp->f_un.f_chan; | |
65 | dev = (dev_t)ip->i_un.i_rdev; | |
66 | mode = ip->i_mode; | |
67 | ||
68 | plock(ip); | |
69 | fp->f_count = 0; | |
70 | if(flag & FPIPE) { | |
71 | ip->i_mode &= ~(IREAD|IWRITE); | |
72 | wakeup((caddr_t)ip+1); | |
73 | wakeup((caddr_t)ip+2); | |
74 | } | |
75 | iput(ip); | |
76 | ||
77 | switch(mode&IFMT) { | |
78 | ||
79 | case IFCHR: | |
80 | case IFMPC: | |
81 | cfunc = cdevsw[major(dev)].d_close; | |
82 | break; | |
83 | ||
84 | case IFBLK: | |
85 | case IFMPB: | |
86 | cfunc = bdevsw[major(dev)].d_close; | |
87 | break; | |
88 | default: | |
89 | return; | |
90 | } | |
91 | ||
92 | if (flag & FMP) | |
93 | goto call; | |
94 | ||
95 | for(fp=file; fp < &file[NFILE]; fp++) | |
96 | if (fp->f_count && fp->f_inode==ip) | |
97 | return; | |
98 | ||
99 | call: | |
100 | (*cfunc)(dev, flag, cp); | |
101 | } | |
102 | ||
103 | /* | |
104 | * openi called to allow handler | |
105 | * of special files to initialize and | |
106 | * validate before actual IO. | |
107 | */ | |
108 | openi(ip, rw) | |
109 | register struct inode *ip; | |
110 | { | |
111 | dev_t dev; | |
112 | register unsigned int maj; | |
113 | ||
114 | dev = (dev_t)ip->i_un.i_rdev; | |
115 | maj = major(dev); | |
116 | switch(ip->i_mode&IFMT) { | |
117 | ||
118 | case IFCHR: | |
119 | case IFMPC: | |
120 | if(maj >= nchrdev) | |
121 | goto bad; | |
122 | (*cdevsw[maj].d_open)(dev, rw); | |
123 | break; | |
124 | ||
125 | case IFBLK: | |
126 | case IFMPB: | |
127 | if(maj >= nblkdev) | |
128 | goto bad; | |
129 | (*bdevsw[maj].d_open)(dev, rw); | |
130 | } | |
131 | return; | |
132 | ||
133 | bad: | |
134 | u.u_error = ENXIO; | |
135 | } | |
136 | ||
137 | /* | |
138 | * Check mode permission on inode pointer. | |
139 | * Mode is READ, WRITE or EXEC. | |
140 | * In the case of WRITE, the | |
141 | * read-only status of the file | |
142 | * system is checked. | |
143 | * Also in WRITE, prototype text | |
144 | * segments cannot be written. | |
145 | * The mode is shifted to select | |
146 | * the owner/group/other fields. | |
147 | * The super user is granted all | |
148 | * permissions. | |
149 | */ | |
150 | access(ip, mode) | |
151 | register struct inode *ip; | |
152 | { | |
153 | register m; | |
154 | ||
155 | m = mode; | |
156 | if(m == IWRITE) { | |
157 | if(getfs(ip->i_dev)->s_ronly != 0) { | |
158 | u.u_error = EROFS; | |
159 | return(1); | |
160 | } | |
161 | if (ip->i_flag&ITEXT) /* try to free text */ | |
162 | xrele(ip); | |
163 | if(ip->i_flag & ITEXT) { | |
164 | u.u_error = ETXTBSY; | |
165 | return(1); | |
166 | } | |
167 | } | |
168 | if(u.u_uid == 0) | |
169 | return(0); | |
170 | if(u.u_uid != ip->i_uid) { | |
171 | m >>= 3; | |
172 | if(u.u_gid != ip->i_gid) | |
173 | m >>= 3; | |
174 | } | |
175 | if((ip->i_mode&m) != 0) | |
176 | return(0); | |
177 | ||
178 | u.u_error = EACCES; | |
179 | return(1); | |
180 | } | |
181 | ||
182 | /* | |
183 | * Look up a pathname and test if | |
184 | * the resultant inode is owned by the | |
185 | * current user. | |
186 | * If not, try for super-user. | |
187 | * If permission is granted, | |
188 | * return inode pointer. | |
189 | */ | |
190 | struct inode * | |
191 | owner() | |
192 | { | |
193 | register struct inode *ip; | |
194 | ||
195 | ip = namei(uchar, 0); | |
196 | if(ip == NULL) | |
197 | return(NULL); | |
198 | if(u.u_uid == ip->i_uid) | |
199 | return(ip); | |
200 | if(suser()) | |
201 | return(ip); | |
202 | iput(ip); | |
203 | return(NULL); | |
204 | } | |
205 | ||
206 | /* | |
207 | * Test if the current user is the | |
208 | * super user. | |
209 | */ | |
210 | suser() | |
211 | { | |
212 | ||
213 | if(u.u_uid == 0) { | |
214 | u.u_acflag |= ASU; | |
215 | return(1); | |
216 | } | |
217 | u.u_error = EPERM; | |
218 | return(0); | |
219 | } | |
220 | ||
221 | /* | |
222 | * Allocate a user file descriptor. | |
223 | */ | |
224 | ufalloc() | |
225 | { | |
226 | register i; | |
227 | ||
228 | for(i=0; i<NOFILE; i++) | |
229 | if(u.u_ofile[i] == NULL) { | |
230 | u.u_r.r_val1 = i; | |
231 | u.u_pofile[i] = 0; | |
232 | return(i); | |
233 | } | |
234 | u.u_error = EMFILE; | |
235 | return(-1); | |
236 | } | |
237 | ||
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); | |
256 | for(fp = &file[0]; fp < &file[NFILE]; fp++) | |
257 | if(fp->f_count == 0) { | |
258 | u.u_ofile[i] = fp; | |
259 | fp->f_count++; | |
260 | fp->f_un.f_offset = 0; | |
261 | return(fp); | |
262 | } | |
263 | printf("no file\n"); | |
264 | u.u_error = ENFILE; | |
265 | return(NULL); | |
266 | } |