xref: /freebsd/sys/fs/pseudofs/pseudofs_fileno.c (revision 2b743a9e9ddc6736208dc8ca1ce06ce64ad20a19)
1 /*-
2  * Copyright (c) 2001 Dag-Erling Co�dan Sm�rgrav
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer
10  *    in this position and unchanged.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_pseudofs.h"
33 
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/systm.h>
37 #include <sys/limits.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/sysctl.h>
42 
43 #include <fs/pseudofs/pseudofs.h>
44 #include <fs/pseudofs/pseudofs_internal.h>
45 
46 /*
47  * Initialize fileno bitmap
48  */
49 void
50 pfs_fileno_init(struct pfs_info *pi)
51 {
52 	struct unrhdr *up;
53 
54 	up = new_unrhdr(3, INT_MAX, &pi->pi_mutex);
55 	mtx_lock(&pi->pi_mutex);
56 	pi->pi_unrhdr = up;
57 	pi->pi_root->pn_fileno = 2;
58 	mtx_unlock(&pi->pi_mutex);
59 }
60 
61 /*
62  * Tear down fileno bitmap
63  */
64 void
65 pfs_fileno_uninit(struct pfs_info *pi)
66 {
67 	struct unrhdr *up;
68 
69 	mtx_lock(&pi->pi_mutex);
70 
71 	up = pi->pi_unrhdr;
72 	pi->pi_unrhdr = NULL;
73 
74 	mtx_unlock(&pi->pi_mutex);
75 
76 	delete_unrhdr(up);
77 }
78 
79 /*
80  * Allocate a file number
81  */
82 void
83 pfs_fileno_alloc(struct pfs_info *pi, struct pfs_node *pn)
84 {
85 	/* make sure our parent has a file number */
86 	if (pn->pn_parent && !pn->pn_parent->pn_fileno)
87 		pfs_fileno_alloc(pi, pn->pn_parent);
88 
89 	switch (pn->pn_type) {
90 	case pfstype_root:
91 	case pfstype_dir:
92 	case pfstype_file:
93 	case pfstype_symlink:
94 	case pfstype_procdir:
95 		pn->pn_fileno = alloc_unr(pi->pi_unrhdr);
96 		break;
97 	case pfstype_this:
98 		KASSERT(pn->pn_parent != NULL,
99 		    ("pfstype_this node has no parent"));
100 		pn->pn_fileno = pn->pn_parent->pn_fileno;
101 		break;
102 	case pfstype_parent:
103 		KASSERT(pn->pn_parent != NULL,
104 		    ("pfstype_parent node has no parent"));
105 		if (pn->pn_parent == pi->pi_root) {
106 			pn->pn_fileno = pn->pn_parent->pn_fileno;
107 			break;
108 		}
109 		KASSERT(pn->pn_parent->pn_parent != NULL,
110 		    ("pfstype_parent node has no grandparent"));
111 		pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno;
112 		break;
113 	case pfstype_none:
114 		KASSERT(0,
115 		    ("pfs_fileno_alloc() called for pfstype_none node"));
116 		break;
117 	}
118 
119 #if 0
120 	printf("pfs_fileno_alloc(): %s: ", pi->pi_name);
121 	if (pn->pn_parent) {
122 		if (pn->pn_parent->pn_parent) {
123 			printf("%s/", pn->pn_parent->pn_parent->pn_name);
124 		}
125 		printf("%s/", pn->pn_parent->pn_name);
126 	}
127 	printf("%s -> %d\n", pn->pn_name, pn->pn_fileno);
128 #endif
129 }
130 
131 /*
132  * Release a file number
133  */
134 void
135 pfs_fileno_free(struct pfs_info *pi, struct pfs_node *pn)
136 {
137 	switch (pn->pn_type) {
138 	case pfstype_root:
139 	case pfstype_dir:
140 	case pfstype_file:
141 	case pfstype_symlink:
142 	case pfstype_procdir:
143 		free_unr(pi->pi_unrhdr, pn->pn_fileno);
144 		break;
145 	case pfstype_this:
146 	case pfstype_parent:
147 		/* ignore these, as they don't "own" their file number */
148 		break;
149 	case pfstype_none:
150 		KASSERT(0,
151 		    ("pfs_fileno_free() called for pfstype_none node"));
152 		break;
153 	}
154 }
155