Commit | Line | Data |
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085641d7 | 1 | /* vfs_lookup.c 4.6 81/04/28 */ |
10873320 BJ |
2 | |
3 | #include "../h/param.h" | |
4 | #include "../h/systm.h" | |
5 | #include "../h/inode.h" | |
6 | #include "../h/mount.h" | |
7 | #include "../h/dir.h" | |
8 | #include "../h/user.h" | |
9 | #include "../h/buf.h" | |
3cbbbe12 | 10 | #include "../h/conf.h" |
10873320 BJ |
11 | |
12 | /* | |
13 | * Convert a pathname into a pointer to | |
14 | * an inode. Note that the inode is locked. | |
15 | * | |
16 | * func = function called to get next char of name | |
17 | * &uchar if name is in user space | |
18 | * &schar if name is in system space | |
19 | * flag = 0 if name is sought | |
20 | * 1 if name is to be created | |
21 | * 2 if name is to be deleted | |
22 | */ | |
23 | struct inode * | |
24 | namei(func, flag) | |
25 | int (*func)(); | |
26 | { | |
27 | register struct inode *dp; | |
28 | register c; | |
29 | register char *cp; | |
30 | struct buf *bp; | |
cee4ba58 | 31 | register struct direct *ep; |
10873320 BJ |
32 | int i; |
33 | dev_t d; | |
34 | off_t eo; | |
085641d7 BJ |
35 | #ifdef CHAOS |
36 | extern long cdevpath; | |
37 | #endif | |
10873320 BJ |
38 | |
39 | /* | |
40 | * If name starts with '/' start from | |
41 | * root; otherwise start from current dir. | |
42 | */ | |
43 | ||
44 | dp = u.u_cdir; | |
45 | if((c=(*func)()) == '/') | |
46 | if ((dp = u.u_rdir) == NULL) | |
47 | dp = rootdir; | |
cee4ba58 | 48 | (void) iget(dp->i_dev, dp->i_number); |
10873320 BJ |
49 | while(c == '/') |
50 | c = (*func)(); | |
51 | if(c == '\0' && flag != 0) | |
52 | u.u_error = ENOENT; | |
53 | ||
54 | cloop: | |
55 | /* | |
56 | * Here dp contains pointer | |
57 | * to last component matched. | |
58 | */ | |
59 | ||
60 | if(u.u_error) | |
61 | goto out; | |
62 | if(c == '\0') | |
63 | return(dp); | |
64 | ||
085641d7 BJ |
65 | #ifdef CHAOS |
66 | if((dp->i_mode & IFMT) == IFCHR && | |
67 | (cdevpath & (1 << major(dp->i_un.i_rdev)))) { | |
68 | u.u_dirp--; | |
69 | return(dp); | |
70 | } | |
71 | #endif | |
10873320 BJ |
72 | /* |
73 | * If there is another component, | |
74 | * Gather up name into | |
75 | * users' dir buffer. | |
76 | */ | |
77 | ||
78 | cp = &u.u_dbuf[0]; | |
79 | while (c != '/' && c != '\0' && u.u_error == 0 ) { | |
80 | if (mpxip!=NULL && c=='!') | |
81 | break; | |
357973de BJ |
82 | if (flag==1 && c == ('/'|0200)) { |
83 | u.u_error = ENOENT; | |
84 | goto out; | |
85 | } | |
cee4ba58 | 86 | if (cp < &u.u_dbuf[DIRSIZ]) |
10873320 BJ |
87 | *cp++ = c; |
88 | c = (*func)(); | |
89 | } | |
90 | while(cp < &u.u_dbuf[DIRSIZ]) | |
91 | *cp++ = '\0'; | |
92 | while(c == '/') | |
93 | c = (*func)(); | |
94 | if (c == '!' && mpxip != NULL) { | |
95 | iput(dp); | |
96 | plock(mpxip); | |
97 | mpxip->i_count++; | |
98 | return(mpxip); | |
99 | } | |
100 | ||
101 | seloop: | |
102 | /* | |
103 | * dp must be a directory and | |
104 | * must have X permission. | |
105 | */ | |
106 | ||
107 | if((dp->i_mode&IFMT) != IFDIR) | |
108 | u.u_error = ENOTDIR; | |
cee4ba58 | 109 | (void) access(dp, IEXEC); |
10873320 BJ |
110 | if(u.u_error) |
111 | goto out; | |
112 | ||
113 | /* | |
114 | * set up to search a directory | |
115 | */ | |
116 | u.u_offset = 0; | |
117 | u.u_segflg = 1; | |
118 | eo = 0; | |
119 | bp = NULL; | |
964bcfb1 BJ |
120 | if (dp == u.u_rdir && u.u_dent.d_name[0] == '.' && |
121 | u.u_dent.d_name[1] == '.' && u.u_dent.d_name[2] == 0) | |
122 | goto cloop; | |
10873320 BJ |
123 | |
124 | eloop: | |
125 | ||
126 | /* | |
127 | * If at the end of the directory, | |
128 | * the search failed. Report what | |
129 | * is appropriate as per flag. | |
130 | */ | |
131 | ||
132 | if(u.u_offset >= dp->i_size) { | |
133 | if(bp != NULL) | |
134 | brelse(bp); | |
7f606d19 | 135 | if(flag==1 && c=='\0' && dp->i_nlink) { |
10873320 BJ |
136 | if(access(dp, IWRITE)) |
137 | goto out; | |
138 | u.u_pdir = dp; | |
139 | if(eo) | |
140 | u.u_offset = eo-sizeof(struct direct); | |
141 | else | |
142 | dp->i_flag |= IUPD|ICHG; | |
143 | return(NULL); | |
144 | } | |
145 | u.u_error = ENOENT; | |
146 | goto out; | |
147 | } | |
148 | ||
149 | /* | |
150 | * If offset is on a block boundary, | |
151 | * read the next directory block. | |
152 | * Release previous if it exists. | |
153 | */ | |
154 | ||
155 | if((u.u_offset&BMASK) == 0) { | |
156 | if(bp != NULL) | |
157 | brelse(bp); | |
158 | bp = bread(dp->i_dev, | |
159 | bmap(dp, (daddr_t)(u.u_offset>>BSHIFT), B_READ)); | |
160 | if (bp->b_flags & B_ERROR) { | |
161 | brelse(bp); | |
162 | goto out; | |
163 | } | |
cee4ba58 BJ |
164 | ep = (struct direct *)bp->b_un.b_addr; |
165 | } else | |
166 | ep++; | |
10873320 BJ |
167 | |
168 | /* | |
169 | * Note first empty directory slot | |
170 | * in eo for possible creat. | |
171 | * String compare the directory entry | |
172 | * and the current component. | |
173 | * If they do not match, go back to eloop. | |
174 | */ | |
175 | ||
10873320 | 176 | u.u_offset += sizeof(struct direct); |
cee4ba58 | 177 | if(ep->d_ino == 0) { |
10873320 BJ |
178 | if(eo == 0) |
179 | eo = u.u_offset; | |
180 | goto eloop; | |
181 | } | |
182 | for(i=0; i<DIRSIZ; i++) { | |
cee4ba58 | 183 | if(u.u_dbuf[i] != ep->d_name[i]) |
10873320 BJ |
184 | goto eloop; |
185 | if(u.u_dbuf[i] == 0) | |
186 | break; | |
187 | } | |
188 | ||
189 | /* | |
190 | * Here a component matched in a directory. | |
191 | * If there is more pathname, go back to | |
192 | * cloop, otherwise return. | |
193 | */ | |
cee4ba58 | 194 | bcopy((caddr_t)ep, (caddr_t)&u.u_dent, sizeof(struct direct)); |
10873320 BJ |
195 | if(bp != NULL) |
196 | brelse(bp); | |
197 | if(flag==2 && c=='\0') { | |
198 | if(access(dp, IWRITE)) | |
199 | goto out; | |
200 | return(dp); | |
201 | } | |
202 | d = dp->i_dev; | |
203 | if(u.u_dent.d_ino == ROOTINO) | |
204 | if(dp->i_number == ROOTINO) | |
205 | if(u.u_dent.d_name[1] == '.') | |
206 | for(i=1; i<NMOUNT; i++) | |
207 | if(mount[i].m_bufp != NULL) | |
208 | if(mount[i].m_dev == d) { | |
209 | iput(dp); | |
210 | dp = mount[i].m_inodp; | |
211 | dp->i_count++; | |
212 | plock(dp); | |
213 | goto seloop; | |
214 | } | |
215 | iput(dp); | |
216 | dp = iget(d, u.u_dent.d_ino); | |
217 | if(dp == NULL) | |
218 | return(NULL); | |
219 | goto cloop; | |
220 | ||
221 | out: | |
222 | iput(dp); | |
223 | return(NULL); | |
224 | } | |
225 | ||
226 | /* | |
227 | * Return the next character from the | |
228 | * kernel string pointed at by dirp. | |
229 | */ | |
230 | schar() | |
231 | { | |
232 | ||
233 | return(*u.u_dirp++ & 0377); | |
234 | } | |
235 | ||
236 | /* | |
237 | * Return the next character from the | |
238 | * user string pointed at by dirp. | |
239 | */ | |
240 | uchar() | |
241 | { | |
242 | register c; | |
243 | ||
244 | c = fubyte(u.u_dirp++); | |
245 | if(c == -1) | |
246 | u.u_error = EFAULT; | |
247 | return(c); | |
248 | } |