xref: /freebsd/sys/fs/pseudofs/pseudofs_fileno.c (revision d4eeb02986980bf33dd56c41ceb9fc5f180c0d47)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer
12  *    in this position and unchanged.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include "opt_pseudofs.h"
35 
36 #include <sys/param.h>
37 #include <sys/kernel.h>
38 #include <sys/systm.h>
39 #include <sys/limits.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/mutex.h>
43 #include <sys/proc.h>
44 #include <sys/sysctl.h>
45 #include <sys/systm.h>
46 
47 #include <fs/pseudofs/pseudofs.h>
48 #include <fs/pseudofs/pseudofs_internal.h>
49 
50 /*
51  * Initialize fileno bitmap
52  */
53 void
54 pfs_fileno_init(struct pfs_info *pi)
55 {
56 
57 	mtx_init(&pi->pi_mutex, "pfs_fileno", NULL, MTX_DEF);
58 	pi->pi_unrhdr = new_unrhdr(3, INT_MAX / NO_PID, &pi->pi_mutex);
59 }
60 
61 /*
62  * Tear down fileno bitmap
63  */
64 void
65 pfs_fileno_uninit(struct pfs_info *pi)
66 {
67 
68 	delete_unrhdr(pi->pi_unrhdr);
69 	pi->pi_unrhdr = NULL;
70 	mtx_destroy(&pi->pi_mutex);
71 }
72 
73 /*
74  * Allocate a file number
75  */
76 void
77 pfs_fileno_alloc(struct pfs_node *pn)
78 {
79 
80 	if (pn->pn_parent)
81 		PFS_TRACE(("%s/%s", pn->pn_parent->pn_name, pn->pn_name));
82 	else
83 		PFS_TRACE(("%s", pn->pn_name));
84 	pfs_assert_not_owned(pn);
85 
86 	switch (pn->pn_type) {
87 	case pfstype_root:
88 		/* root must always be 2 */
89 		pn->pn_fileno = 2;
90 		break;
91 	case pfstype_dir:
92 	case pfstype_file:
93 	case pfstype_symlink:
94 	case pfstype_procdir:
95 		pn->pn_fileno = alloc_unr(pn->pn_info->pi_unrhdr);
96 		break;
97 	case pfstype_this:
98 		KASSERT(pn->pn_parent != NULL,
99 		    ("%s(): pfstype_this node has no parent", __func__));
100 		pn->pn_fileno = pn->pn_parent->pn_fileno;
101 		break;
102 	case pfstype_parent:
103 		KASSERT(pn->pn_parent != NULL,
104 		    ("%s(): pfstype_parent node has no parent", __func__));
105 		if (pn->pn_parent->pn_type == pfstype_root) {
106 			pn->pn_fileno = pn->pn_parent->pn_fileno;
107 			break;
108 		}
109 		KASSERT(pn->pn_parent->pn_parent != NULL,
110 		    ("%s(): pfstype_parent node has no grandparent", __func__));
111 		pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno;
112 		break;
113 	case pfstype_none:
114 		KASSERT(0,
115 		    ("%s(): pfstype_none node", __func__));
116 		break;
117 	}
118 
119 #if 0
120 	printf("%s(): %s: ", __func__, pn->pn_info->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_node *pn)
136 {
137 
138 	pfs_assert_not_owned(pn);
139 
140 	switch (pn->pn_type) {
141 	case pfstype_root:
142 		/* not allocated from unrhdr */
143 		return;
144 	case pfstype_dir:
145 	case pfstype_file:
146 	case pfstype_symlink:
147 	case pfstype_procdir:
148 		free_unr(pn->pn_info->pi_unrhdr, pn->pn_fileno);
149 		break;
150 	case pfstype_this:
151 	case pfstype_parent:
152 		/* ignore these, as they don't "own" their file number */
153 		break;
154 	case pfstype_none:
155 		KASSERT(0,
156 		    ("pfs_fileno_free() called for pfstype_none node"));
157 		break;
158 	}
159 }
160