xref: /minix3/minix/lib/libvtreefs/link.c (revision 7c48de6cc4c6d56f2277d378dba01dbac8a8c3b9)
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