| Willy Tarreau | 982b6e3 | 2009-01-25 13:49:53 +0100 | [diff] [blame] | 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 | |
| 15 | #include <common/config.h> |
| 16 | #include <common/memory.h> |
| 17 | |
| 18 | #include <types/global.h> |
| 19 | #include <types/pipe.h> |
| 20 | |
| 21 | struct pool_head *pool2_pipe = NULL; |
| 22 | struct pipe *pipes_live = NULL; /* pipes which are still ready to use */ |
| 23 | int pipes_used = 0; /* # of pipes in use (2 fds each) */ |
| 24 | int pipes_free = 0; /* # of pipes unused */ |
| 25 | |
| 26 | /* allocate memory for the pipes */ |
| 27 | static void init_pipe() |
| 28 | { |
| 29 | pool2_pipe = create_pool("pipe", sizeof(struct pipe), MEM_F_SHARED); |
| 30 | pipes_used = 0; |
| 31 | pipes_free = 0; |
| 32 | } |
| 33 | |
| 34 | /* return a pre-allocated empty pipe. Try to allocate one if there isn't any |
| 35 | * left. NULL is returned if a pipe could not be allocated. |
| 36 | */ |
| 37 | struct pipe *get_pipe() |
| 38 | { |
| 39 | struct pipe *ret; |
| 40 | int pipefd[2]; |
| 41 | |
| 42 | if (likely(pipes_live)) { |
| 43 | ret = pipes_live; |
| 44 | pipes_live = pipes_live->next; |
| 45 | pipes_free--; |
| 46 | pipes_used++; |
| 47 | return ret; |
| 48 | } |
| 49 | |
| 50 | if (pipes_used >= global.maxpipes) |
| 51 | return NULL; |
| 52 | |
| 53 | ret = pool_alloc2(pool2_pipe); |
| 54 | if (!ret) |
| 55 | return NULL; |
| 56 | |
| 57 | if (pipe(pipefd) < 0) { |
| 58 | pool_free2(pool2_pipe, ret); |
| 59 | return NULL; |
| 60 | } |
| 61 | ret->data = 0; |
| 62 | ret->prod = pipefd[1]; |
| 63 | ret->cons = pipefd[0]; |
| 64 | ret->next = NULL; |
| 65 | pipes_used++; |
| 66 | return ret; |
| 67 | } |
| 68 | |
| 69 | /* destroy a pipe, possibly because an error was encountered on it. Its FDs |
| 70 | * will be closed and it will not be reinjected into the live pool. |
| 71 | */ |
| 72 | void kill_pipe(struct pipe *p) |
| 73 | { |
| 74 | close(p->prod); |
| 75 | close(p->cons); |
| 76 | pool_free2(pool2_pipe, p); |
| 77 | pipes_used--; |
| 78 | return; |
| 79 | } |
| 80 | |
| 81 | /* put back a unused pipe into the live pool. If it still has data in it, it is |
| 82 | * closed and not reinjected into the live pool. The caller is not allowed to |
| 83 | * use it once released. |
| 84 | */ |
| 85 | void put_pipe(struct pipe *p) |
| 86 | { |
| 87 | if (p->data) { |
| 88 | kill_pipe(p); |
| 89 | return; |
| 90 | } |
| 91 | p->next = pipes_live; |
| 92 | pipes_live = p; |
| 93 | pipes_free++; |
| 94 | pipes_used--; |
| 95 | } |
| 96 | |
| 97 | |
| 98 | __attribute__((constructor)) |
| 99 | static void __pipe_module_init(void) |
| 100 | { |
| 101 | init_pipe(); |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * Local variables: |
| 106 | * c-indent-level: 8 |
| 107 | * c-basic-offset: 8 |
| 108 | * End: |
| 109 | */ |