1 | /* $NetBSD: vfs_cwd.c,v 1.4 2011/02/15 15:54:28 pooka Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 2008 The NetBSD Foundation, Inc. |
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 | * 2. Redistributions in binary form must reproduce the above copyright |
13 | * notice, this list of conditions and the following disclaimer in the |
14 | * documentation and/or other materials provided with the distribution. |
15 | * |
16 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
17 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
18 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
19 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
20 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
26 | * POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
28 | |
29 | /* |
30 | * Current working directory. |
31 | */ |
32 | |
33 | #include <sys/cdefs.h> |
34 | __KERNEL_RCSID(0, "$NetBSD: vfs_cwd.c,v 1.4 2011/02/15 15:54:28 pooka Exp $" ); |
35 | |
36 | #include <sys/param.h> |
37 | #include <sys/atomic.h> |
38 | #include <sys/filedesc.h> |
39 | #include <sys/proc.h> |
40 | #include <sys/vnode.h> |
41 | |
42 | static int cwdi_ctor(void *, void *, int); |
43 | static void cwdi_dtor(void *, void *); |
44 | |
45 | static pool_cache_t cwdi_cache; |
46 | |
47 | void |
48 | cwd_sys_init(void) |
49 | { |
50 | |
51 | cwdi_cache = pool_cache_init(sizeof(struct cwdinfo), coherency_unit, |
52 | 0, 0, "cwdi" , NULL, IPL_NONE, cwdi_ctor, cwdi_dtor, NULL); |
53 | KASSERT(cwdi_cache != NULL); |
54 | } |
55 | |
56 | /* |
57 | * Create an initial cwdinfo structure, using the same current and root |
58 | * directories as curproc. |
59 | */ |
60 | struct cwdinfo * |
61 | cwdinit(void) |
62 | { |
63 | struct cwdinfo *cwdi; |
64 | struct cwdinfo *copy; |
65 | |
66 | cwdi = pool_cache_get(cwdi_cache, PR_WAITOK); |
67 | copy = curproc->p_cwdi; |
68 | |
69 | rw_enter(©->cwdi_lock, RW_READER); |
70 | cwdi->cwdi_cdir = copy->cwdi_cdir; |
71 | if (cwdi->cwdi_cdir) |
72 | vref(cwdi->cwdi_cdir); |
73 | cwdi->cwdi_rdir = copy->cwdi_rdir; |
74 | if (cwdi->cwdi_rdir) |
75 | vref(cwdi->cwdi_rdir); |
76 | cwdi->cwdi_edir = copy->cwdi_edir; |
77 | if (cwdi->cwdi_edir) |
78 | vref(cwdi->cwdi_edir); |
79 | cwdi->cwdi_cmask = copy->cwdi_cmask; |
80 | cwdi->cwdi_refcnt = 1; |
81 | rw_exit(©->cwdi_lock); |
82 | |
83 | return (cwdi); |
84 | } |
85 | |
86 | static int |
87 | cwdi_ctor(void *arg, void *obj, int flags) |
88 | { |
89 | struct cwdinfo *cwdi = obj; |
90 | |
91 | rw_init(&cwdi->cwdi_lock); |
92 | |
93 | return 0; |
94 | } |
95 | |
96 | static void |
97 | cwdi_dtor(void *arg, void *obj) |
98 | { |
99 | struct cwdinfo *cwdi = obj; |
100 | |
101 | rw_destroy(&cwdi->cwdi_lock); |
102 | } |
103 | |
104 | /* |
105 | * Make p2 share p1's cwdinfo. |
106 | */ |
107 | void |
108 | cwdshare(struct proc *p2) |
109 | { |
110 | struct cwdinfo *cwdi; |
111 | |
112 | cwdi = curproc->p_cwdi; |
113 | |
114 | atomic_inc_uint(&cwdi->cwdi_refcnt); |
115 | p2->p_cwdi = cwdi; |
116 | } |
117 | |
118 | /* |
119 | * Make sure proc has only one reference to its cwdi, creating |
120 | * a new one if necessary. |
121 | */ |
122 | void |
123 | cwdunshare(struct proc *p) |
124 | { |
125 | struct cwdinfo *cwdi = p->p_cwdi; |
126 | |
127 | if (cwdi->cwdi_refcnt > 1) { |
128 | cwdi = cwdinit(); |
129 | cwdfree(p->p_cwdi); |
130 | p->p_cwdi = cwdi; |
131 | } |
132 | } |
133 | |
134 | /* |
135 | * Release a cwdinfo structure. |
136 | */ |
137 | void |
138 | cwdfree(struct cwdinfo *cwdi) |
139 | { |
140 | |
141 | if (atomic_dec_uint_nv(&cwdi->cwdi_refcnt) > 0) |
142 | return; |
143 | |
144 | vrele(cwdi->cwdi_cdir); |
145 | if (cwdi->cwdi_rdir) |
146 | vrele(cwdi->cwdi_rdir); |
147 | if (cwdi->cwdi_edir) |
148 | vrele(cwdi->cwdi_edir); |
149 | pool_cache_put(cwdi_cache, cwdi); |
150 | } |
151 | |
152 | void |
153 | cwdexec(struct proc *p) |
154 | { |
155 | |
156 | cwdunshare(p); |
157 | |
158 | if (p->p_cwdi->cwdi_edir) { |
159 | vrele(p->p_cwdi->cwdi_edir); |
160 | } |
161 | } |
162 | |