Commit | Line | Data |
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964bcfb1 | 1 | /* vfs_lookup.c 4.5 81/03/09 */ |
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 | ||
62 | /* | |
63 | * If there is another component, | |
64 | * Gather up name into | |
65 | * users' dir buffer. | |
66 | */ | |
67 | ||
68 | cp = &u.u_dbuf[0]; | |
69 | while (c != '/' && c != '\0' && u.u_error == 0 ) { | |
70 | if (mpxip!=NULL && c=='!') | |
71 | break; | |
357973de BJ |
72 | if (flag==1 && c == ('/'|0200)) { |
73 | u.u_error = ENOENT; | |
74 | goto out; | |
75 | } | |
cee4ba58 | 76 | if (cp < &u.u_dbuf[DIRSIZ]) |
10873320 BJ |
77 | *cp++ = c; |
78 | c = (*func)(); | |
79 | } | |
80 | while(cp < &u.u_dbuf[DIRSIZ]) | |
81 | *cp++ = '\0'; | |
82 | while(c == '/') | |
83 | c = (*func)(); | |
84 | if (c == '!' && mpxip != NULL) { | |
85 | iput(dp); | |
86 | plock(mpxip); | |
87 | mpxip->i_count++; | |
88 | return(mpxip); | |
89 | } | |
90 | ||
91 | seloop: | |
92 | /* | |
93 | * dp must be a directory and | |
94 | * must have X permission. | |
95 | */ | |
96 | ||
97 | if((dp->i_mode&IFMT) != IFDIR) | |
98 | u.u_error = ENOTDIR; | |
cee4ba58 | 99 | (void) access(dp, IEXEC); |
10873320 BJ |
100 | if(u.u_error) |
101 | goto out; | |
102 | ||
103 | /* | |
104 | * set up to search a directory | |
105 | */ | |
106 | u.u_offset = 0; | |
107 | u.u_segflg = 1; | |
108 | eo = 0; | |
109 | bp = NULL; | |
964bcfb1 BJ |
110 | if (dp == u.u_rdir && u.u_dent.d_name[0] == '.' && |
111 | u.u_dent.d_name[1] == '.' && u.u_dent.d_name[2] == 0) | |
112 | goto cloop; | |
10873320 BJ |
113 | |
114 | eloop: | |
115 | ||
116 | /* | |
117 | * If at the end of the directory, | |
118 | * the search failed. Report what | |
119 | * is appropriate as per flag. | |
120 | */ | |
121 | ||
122 | if(u.u_offset >= dp->i_size) { | |
123 | if(bp != NULL) | |
124 | brelse(bp); | |
7f606d19 | 125 | if(flag==1 && c=='\0' && dp->i_nlink) { |
10873320 BJ |
126 | if(access(dp, IWRITE)) |
127 | goto out; | |
128 | u.u_pdir = dp; | |
129 | if(eo) | |
130 | u.u_offset = eo-sizeof(struct direct); | |
131 | else | |
132 | dp->i_flag |= IUPD|ICHG; | |
133 | return(NULL); | |
134 | } | |
135 | u.u_error = ENOENT; | |
136 | goto out; | |
137 | } | |
138 | ||
139 | /* | |
140 | * If offset is on a block boundary, | |
141 | * read the next directory block. | |
142 | * Release previous if it exists. | |
143 | */ | |
144 | ||
145 | if((u.u_offset&BMASK) == 0) { | |
146 | if(bp != NULL) | |
147 | brelse(bp); | |
148 | bp = bread(dp->i_dev, | |
149 | bmap(dp, (daddr_t)(u.u_offset>>BSHIFT), B_READ)); | |
150 | if (bp->b_flags & B_ERROR) { | |
151 | brelse(bp); | |
152 | goto out; | |
153 | } | |
cee4ba58 BJ |
154 | ep = (struct direct *)bp->b_un.b_addr; |
155 | } else | |
156 | ep++; | |
10873320 BJ |
157 | |
158 | /* | |
159 | * Note first empty directory slot | |
160 | * in eo for possible creat. | |
161 | * String compare the directory entry | |
162 | * and the current component. | |
163 | * If they do not match, go back to eloop. | |
164 | */ | |
165 | ||
10873320 | 166 | u.u_offset += sizeof(struct direct); |
cee4ba58 | 167 | if(ep->d_ino == 0) { |
10873320 BJ |
168 | if(eo == 0) |
169 | eo = u.u_offset; | |
170 | goto eloop; | |
171 | } | |
172 | for(i=0; i<DIRSIZ; i++) { | |
cee4ba58 | 173 | if(u.u_dbuf[i] != ep->d_name[i]) |
10873320 BJ |
174 | goto eloop; |
175 | if(u.u_dbuf[i] == 0) | |
176 | break; | |
177 | } | |
178 | ||
179 | /* | |
180 | * Here a component matched in a directory. | |
181 | * If there is more pathname, go back to | |
182 | * cloop, otherwise return. | |
183 | */ | |
cee4ba58 | 184 | bcopy((caddr_t)ep, (caddr_t)&u.u_dent, sizeof(struct direct)); |
10873320 BJ |
185 | if(bp != NULL) |
186 | brelse(bp); | |
187 | if(flag==2 && c=='\0') { | |
188 | if(access(dp, IWRITE)) | |
189 | goto out; | |
190 | return(dp); | |
191 | } | |
192 | d = dp->i_dev; | |
193 | if(u.u_dent.d_ino == ROOTINO) | |
194 | if(dp->i_number == ROOTINO) | |
195 | if(u.u_dent.d_name[1] == '.') | |
196 | for(i=1; i<NMOUNT; i++) | |
197 | if(mount[i].m_bufp != NULL) | |
198 | if(mount[i].m_dev == d) { | |
199 | iput(dp); | |
200 | dp = mount[i].m_inodp; | |
201 | dp->i_count++; | |
202 | plock(dp); | |
203 | goto seloop; | |
204 | } | |
205 | iput(dp); | |
206 | dp = iget(d, u.u_dent.d_ino); | |
207 | if(dp == NULL) | |
208 | return(NULL); | |
209 | goto cloop; | |
210 | ||
211 | out: | |
212 | iput(dp); | |
213 | return(NULL); | |
214 | } | |
215 | ||
216 | /* | |
217 | * Return the next character from the | |
218 | * kernel string pointed at by dirp. | |
219 | */ | |
220 | schar() | |
221 | { | |
222 | ||
223 | return(*u.u_dirp++ & 0377); | |
224 | } | |
225 | ||
226 | /* | |
227 | * Return the next character from the | |
228 | * user string pointed at by dirp. | |
229 | */ | |
230 | uchar() | |
231 | { | |
232 | register c; | |
233 | ||
234 | c = fubyte(u.u_dirp++); | |
235 | if(c == -1) | |
236 | u.u_error = EFAULT; | |
237 | return(c); | |
238 | } |