1 /*
2 * Pipe management
3 *
4 * Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 */
12
13 #include <unistd.h>
14 #include <fcntl.h>
15
16 #include <haproxy/api.h>
17 #include <haproxy/global.h>
18 #include <haproxy/pipe-t.h>
19 #include <haproxy/pool.h>
20 #include <haproxy/thread.h>
21
22
23 DECLARE_STATIC_POOL(pool_head_pipe, "pipe", sizeof(struct pipe));
24
25 struct pipe *pipes_live = NULL; /* pipes which are still ready to use */
26
27 __decl_spinlock(pipes_lock); /* lock used to protect pipes list */
28
29 static THREAD_LOCAL int local_pipes_free = 0; /* #cache objects */
30 static THREAD_LOCAL struct pipe *local_pipes = NULL;
31
32 int pipes_used = 0; /* # of pipes in use (2 fds each) */
33 int pipes_free = 0; /* # of pipes unused */
34
35 /* return a pre-allocated empty pipe. Try to allocate one if there isn't any
36 * left. NULL is returned if a pipe could not be allocated.
37 */
get_pipe()38 struct pipe *get_pipe()
39 {
40 struct pipe *ret = NULL;
41 int pipefd[2];
42
43 ret = local_pipes;
44 if (likely(ret)) {
45 local_pipes = ret->next;
46 local_pipes_free--;
47 HA_ATOMIC_SUB(&pipes_free, 1);
48 HA_ATOMIC_ADD(&pipes_used, 1);
49 goto out;
50 }
51
52 if (likely(pipes_live)) {
53 HA_SPIN_LOCK(PIPES_LOCK, &pipes_lock);
54 ret = pipes_live;
55 if (likely(ret))
56 pipes_live = ret->next;
57 HA_SPIN_UNLOCK(PIPES_LOCK, &pipes_lock);
58 if (ret) {
59 HA_ATOMIC_SUB(&pipes_free, 1);
60 HA_ATOMIC_ADD(&pipes_used, 1);
61 goto out;
62 }
63 }
64
65 HA_ATOMIC_ADD(&pipes_used, 1);
66 if (pipes_used + pipes_free >= global.maxpipes)
67 goto fail;
68
69 ret = pool_alloc(pool_head_pipe);
70 if (!ret)
71 goto fail;
72
73 if (pipe(pipefd) < 0)
74 goto fail;
75
76 #ifdef F_SETPIPE_SZ
77 if (global.tune.pipesize)
78 fcntl(pipefd[0], F_SETPIPE_SZ, global.tune.pipesize);
79 #endif
80 ret->data = 0;
81 ret->prod = pipefd[1];
82 ret->cons = pipefd[0];
83 ret->next = NULL;
84 out:
85 return ret;
86 fail:
87 pool_free(pool_head_pipe, ret);
88 HA_ATOMIC_SUB(&pipes_used, 1);
89 return NULL;
90
91 }
92
93 /* destroy a pipe, possibly because an error was encountered on it. Its FDs
94 * will be closed and it will not be reinjected into the live pool.
95 */
kill_pipe(struct pipe * p)96 void kill_pipe(struct pipe *p)
97 {
98 close(p->prod);
99 close(p->cons);
100 pool_free(pool_head_pipe, p);
101 HA_ATOMIC_SUB(&pipes_used, 1);
102 }
103
104 /* put back a unused pipe into the live pool. If it still has data in it, it is
105 * closed and not reinjected into the live pool. The caller is not allowed to
106 * use it once released.
107 */
put_pipe(struct pipe * p)108 void put_pipe(struct pipe *p)
109 {
110 if (unlikely(p->data)) {
111 kill_pipe(p);
112 return;
113 }
114
115 if (likely(local_pipes_free * global.nbthread < global.maxpipes - pipes_used)) {
116 p->next = local_pipes;
117 local_pipes = p;
118 local_pipes_free++;
119 goto out;
120 }
121
122 HA_SPIN_LOCK(PIPES_LOCK, &pipes_lock);
123 p->next = pipes_live;
124 pipes_live = p;
125 HA_SPIN_UNLOCK(PIPES_LOCK, &pipes_lock);
126 out:
127 HA_ATOMIC_ADD(&pipes_free, 1);
128 HA_ATOMIC_SUB(&pipes_used, 1);
129 }
130
131 /*
132 * Local variables:
133 * c-indent-level: 8
134 * c-basic-offset: 8
135 * End:
136 */
137