1 /* VTreeFS - link.c - support for symbolic links and device nodes */
2
3 #include "inc.h"
4
5 /*
6 * Retrieve a symbolic link target.
7 */
8 ssize_t
fs_rdlink(ino_t ino_nr,struct fsdriver_data * data,size_t bytes)9 fs_rdlink(ino_t ino_nr, struct fsdriver_data * data, size_t bytes)
10 {
11 char path[PATH_MAX];
12 struct inode *node;
13 size_t len;
14 int r;
15
16 if ((node = find_inode(ino_nr)) == NULL)
17 return EINVAL;
18
19 /* The hook should be provided for any FS that adds symlink inodes.. */
20 if (vtreefs_hooks->rdlink_hook == NULL)
21 return ENOSYS;
22
23 assert(!is_inode_deleted(node)); /* symlinks cannot be opened */
24
25 r = vtreefs_hooks->rdlink_hook(node, path, sizeof(path),
26 get_inode_cbdata(node));
27 if (r != OK) return r;
28
29 len = strlen(path);
30 assert(len > 0 && len < sizeof(path));
31
32 if (len > bytes)
33 len = bytes;
34
35 /* Copy out the result. */
36 if ((r = fsdriver_copyout(data, 0, path, len)) != OK)
37 return r;
38
39 return len;
40 }
41
42 /*
43 * Create a symbolic link.
44 */
45 int
fs_slink(ino_t dir_nr,char * name,uid_t uid,gid_t gid,struct fsdriver_data * data,size_t bytes)46 fs_slink(ino_t dir_nr, char * name, uid_t uid, gid_t gid,
47 struct fsdriver_data * data, size_t bytes)
48 {
49 char path[PATH_MAX];
50 struct inode *node;
51 struct inode_stat istat;
52 int r;
53
54 if ((node = find_inode(dir_nr)) == NULL)
55 return EINVAL;
56
57 if (vtreefs_hooks->slink_hook == NULL)
58 return ENOSYS;
59
60 if (get_inode_by_name(node, name) != NULL)
61 return EEXIST;
62
63 if (bytes >= sizeof(path))
64 return ENAMETOOLONG;
65
66 if ((r = fsdriver_copyin(data, 0, path, bytes)) != OK)
67 return r;
68 path[bytes] = 0;
69
70 memset(&istat, 0, sizeof(istat));
71 istat.mode = S_IFLNK | RWX_MODES;
72 istat.uid = uid;
73 istat.gid = gid;
74 istat.size = strlen(path);
75 istat.dev = 0;
76
77 return vtreefs_hooks->slink_hook(node, name, &istat, path,
78 get_inode_cbdata(node));
79 }
80
81 /*
82 * Create a device node.
83 */
84 int
fs_mknod(ino_t dir_nr,char * name,mode_t mode,uid_t uid,gid_t gid,dev_t rdev)85 fs_mknod(ino_t dir_nr, char * name, mode_t mode, uid_t uid, gid_t gid,
86 dev_t rdev)
87 {
88 struct inode *node;
89 struct inode_stat istat;
90
91 if ((node = find_inode(dir_nr)) == NULL)
92 return EINVAL;
93
94 if (get_inode_by_name(node, name) != NULL)
95 return EEXIST;
96
97 if (vtreefs_hooks->mknod_hook == NULL)
98 return ENOSYS;
99
100 memset(&istat, 0, sizeof(istat));
101 istat.mode = mode;
102 istat.uid = uid;
103 istat.gid = gid;
104 istat.size = 0;
105 istat.dev = rdev;
106
107 return vtreefs_hooks->mknod_hook(node, name, &istat,
108 get_inode_cbdata(node));
109 }
110
111 /*
112 * Unlink a node.
113 */
114 int
fs_unlink(ino_t dir_nr,char * name,int __unused call)115 fs_unlink(ino_t dir_nr, char * name, int __unused call)
116 {
117 struct inode *dir_node, *node;
118
119 if ((dir_node = find_inode(dir_nr)) == NULL)
120 return EINVAL;
121
122 if ((node = get_inode_by_name(dir_node, name)) == NULL)
123 return ENOENT;
124
125 if (vtreefs_hooks->unlink_hook == NULL)
126 return ENOSYS;
127
128 return vtreefs_hooks->unlink_hook(node, get_inode_cbdata(node));
129 }
130