Commit | Line | Data |
---|---|---|
3cbbbe12 | 1 | /* vfs_lookup.c 4.3 %G% */ |
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; | |
35 | ||
36 | /* | |
37 | * If name starts with '/' start from | |
38 | * root; otherwise start from current dir. | |
39 | */ | |
40 | ||
41 | dp = u.u_cdir; | |
42 | if((c=(*func)()) == '/') | |
43 | if ((dp = u.u_rdir) == NULL) | |
44 | dp = rootdir; | |
cee4ba58 | 45 | (void) iget(dp->i_dev, dp->i_number); |
10873320 BJ |
46 | while(c == '/') |
47 | c = (*func)(); | |
48 | if(c == '\0' && flag != 0) | |
49 | u.u_error = ENOENT; | |
50 | ||
51 | cloop: | |
52 | /* | |
53 | * Here dp contains pointer | |
54 | * to last component matched. | |
55 | */ | |
56 | ||
57 | if(u.u_error) | |
58 | goto out; | |
59 | if(c == '\0') | |
60 | return(dp); | |
61 | ||
3cbbbe12 BJ |
62 | #ifdef CHAOS |
63 | if((dp->i_mode&IFMT) == IFCHR && cdevpath & (1 << major(dp->i_un.i_rdev)) ) { | |
64 | u.u_dirp--; | |
65 | return(dp); | |
66 | } | |
67 | #endif | |
68 | ||
10873320 BJ |
69 | /* |
70 | * If there is another component, | |
71 | * Gather up name into | |
72 | * users' dir buffer. | |
73 | */ | |
74 | ||
75 | cp = &u.u_dbuf[0]; | |
76 | while (c != '/' && c != '\0' && u.u_error == 0 ) { | |
77 | if (mpxip!=NULL && c=='!') | |
78 | break; | |
357973de BJ |
79 | if (flag==1 && c == ('/'|0200)) { |
80 | u.u_error = ENOENT; | |
81 | goto out; | |
82 | } | |
cee4ba58 | 83 | if (cp < &u.u_dbuf[DIRSIZ]) |
10873320 BJ |
84 | *cp++ = c; |
85 | c = (*func)(); | |
86 | } | |
87 | while(cp < &u.u_dbuf[DIRSIZ]) | |
88 | *cp++ = '\0'; | |
89 | while(c == '/') | |
90 | c = (*func)(); | |
91 | if (c == '!' && mpxip != NULL) { | |
92 | iput(dp); | |
93 | plock(mpxip); | |
94 | mpxip->i_count++; | |
95 | return(mpxip); | |
96 | } | |
97 | ||
98 | seloop: | |
99 | /* | |
100 | * dp must be a directory and | |
101 | * must have X permission. | |
102 | */ | |
103 | ||
104 | if((dp->i_mode&IFMT) != IFDIR) | |
105 | u.u_error = ENOTDIR; | |
cee4ba58 | 106 | (void) access(dp, IEXEC); |
10873320 BJ |
107 | if(u.u_error) |
108 | goto out; | |
109 | ||
110 | /* | |
111 | * set up to search a directory | |
112 | */ | |
113 | u.u_offset = 0; | |
114 | u.u_segflg = 1; | |
115 | eo = 0; | |
116 | bp = NULL; | |
117 | ||
118 | eloop: | |
119 | ||
120 | /* | |
121 | * If at the end of the directory, | |
122 | * the search failed. Report what | |
123 | * is appropriate as per flag. | |
124 | */ | |
125 | ||
126 | if(u.u_offset >= dp->i_size) { | |
127 | if(bp != NULL) | |
128 | brelse(bp); | |
7f606d19 | 129 | if(flag==1 && c=='\0' && dp->i_nlink) { |
10873320 BJ |
130 | if(access(dp, IWRITE)) |
131 | goto out; | |
132 | u.u_pdir = dp; | |
133 | if(eo) | |
134 | u.u_offset = eo-sizeof(struct direct); | |
135 | else | |
136 | dp->i_flag |= IUPD|ICHG; | |
137 | return(NULL); | |
138 | } | |
139 | u.u_error = ENOENT; | |
140 | goto out; | |
141 | } | |
142 | ||
143 | /* | |
144 | * If offset is on a block boundary, | |
145 | * read the next directory block. | |
146 | * Release previous if it exists. | |
147 | */ | |
148 | ||
149 | if((u.u_offset&BMASK) == 0) { | |
150 | if(bp != NULL) | |
151 | brelse(bp); | |
152 | bp = bread(dp->i_dev, | |
153 | bmap(dp, (daddr_t)(u.u_offset>>BSHIFT), B_READ)); | |
154 | if (bp->b_flags & B_ERROR) { | |
155 | brelse(bp); | |
156 | goto out; | |
157 | } | |
cee4ba58 BJ |
158 | ep = (struct direct *)bp->b_un.b_addr; |
159 | } else | |
160 | ep++; | |
10873320 BJ |
161 | |
162 | /* | |
163 | * Note first empty directory slot | |
164 | * in eo for possible creat. | |
165 | * String compare the directory entry | |
166 | * and the current component. | |
167 | * If they do not match, go back to eloop. | |
168 | */ | |
169 | ||
10873320 | 170 | u.u_offset += sizeof(struct direct); |
cee4ba58 | 171 | if(ep->d_ino == 0) { |
10873320 BJ |
172 | if(eo == 0) |
173 | eo = u.u_offset; | |
174 | goto eloop; | |
175 | } | |
176 | for(i=0; i<DIRSIZ; i++) { | |
cee4ba58 | 177 | if(u.u_dbuf[i] != ep->d_name[i]) |
10873320 BJ |
178 | goto eloop; |
179 | if(u.u_dbuf[i] == 0) | |
180 | break; | |
181 | } | |
182 | ||
183 | /* | |
184 | * Here a component matched in a directory. | |
185 | * If there is more pathname, go back to | |
186 | * cloop, otherwise return. | |
187 | */ | |
cee4ba58 | 188 | bcopy((caddr_t)ep, (caddr_t)&u.u_dent, sizeof(struct direct)); |
10873320 BJ |
189 | if(bp != NULL) |
190 | brelse(bp); | |
191 | if(flag==2 && c=='\0') { | |
192 | if(access(dp, IWRITE)) | |
193 | goto out; | |
194 | return(dp); | |
195 | } | |
196 | d = dp->i_dev; | |
197 | if(u.u_dent.d_ino == ROOTINO) | |
198 | if(dp->i_number == ROOTINO) | |
199 | if(u.u_dent.d_name[1] == '.') | |
200 | for(i=1; i<NMOUNT; i++) | |
201 | if(mount[i].m_bufp != NULL) | |
202 | if(mount[i].m_dev == d) { | |
203 | iput(dp); | |
204 | dp = mount[i].m_inodp; | |
205 | dp->i_count++; | |
206 | plock(dp); | |
207 | goto seloop; | |
208 | } | |
209 | iput(dp); | |
210 | dp = iget(d, u.u_dent.d_ino); | |
211 | if(dp == NULL) | |
212 | return(NULL); | |
213 | goto cloop; | |
214 | ||
215 | out: | |
216 | iput(dp); | |
217 | return(NULL); | |
218 | } | |
219 | ||
220 | /* | |
221 | * Return the next character from the | |
222 | * kernel string pointed at by dirp. | |
223 | */ | |
224 | schar() | |
225 | { | |
226 | ||
227 | return(*u.u_dirp++ & 0377); | |
228 | } | |
229 | ||
230 | /* | |
231 | * Return the next character from the | |
232 | * user string pointed at by dirp. | |
233 | */ | |
234 | uchar() | |
235 | { | |
236 | register c; | |
237 | ||
238 | c = fubyte(u.u_dirp++); | |
239 | if(c == -1) | |
240 | u.u_error = EFAULT; | |
241 | return(c); | |
242 | } |