Contents of /trunk/mkinitrd-magellan/busybox/networking/udhcp/signalpipe.c
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Revision 984 -
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Sun May 30 11:32:42 2010 UTC (13 years, 11 months ago) by niro
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Sun May 30 11:32:42 2010 UTC (13 years, 11 months ago) by niro
File MIME type: text/plain
File size: 2286 byte(s)
-updated to busybox-1.16.1 and enabled blkid/uuid support in default config
1 | /* vi: set sw=4 ts=4: */ |
2 | /* signalpipe.c |
3 | * |
4 | * Signal pipe infrastructure. A reliable way of delivering signals. |
5 | * |
6 | * Russ Dill <Russ.Dill@asu.edu> December 2003 |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License as published by |
10 | * the Free Software Foundation; either version 2 of the License, or |
11 | * (at your option) any later version. |
12 | * |
13 | * This program is distributed in the hope that it will be useful, |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
16 | * GNU General Public License for more details. |
17 | * |
18 | * You should have received a copy of the GNU General Public License |
19 | * along with this program; if not, write to the Free Software |
20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
21 | */ |
22 | |
23 | #include "common.h" |
24 | |
25 | |
26 | static struct fd_pair signal_pipe; |
27 | |
28 | static void signal_handler(int sig) |
29 | { |
30 | unsigned char ch = sig; /* use char, avoid dealing with partial writes */ |
31 | if (write(signal_pipe.wr, &ch, 1) != 1) |
32 | bb_perror_msg("can't send signal"); |
33 | } |
34 | |
35 | |
36 | /* Call this before doing anything else. Sets up the socket pair |
37 | * and installs the signal handler */ |
38 | void FAST_FUNC udhcp_sp_setup(void) |
39 | { |
40 | /* was socketpair, but it needs AF_UNIX in kernel */ |
41 | xpiped_pair(signal_pipe); |
42 | close_on_exec_on(signal_pipe.rd); |
43 | close_on_exec_on(signal_pipe.wr); |
44 | ndelay_on(signal_pipe.wr); |
45 | bb_signals(0 |
46 | + (1 << SIGUSR1) |
47 | + (1 << SIGUSR2) |
48 | + (1 << SIGTERM) |
49 | , signal_handler); |
50 | } |
51 | |
52 | |
53 | /* Quick little function to setup the rfds. Will return the |
54 | * max_fd for use with select. Limited in that you can only pass |
55 | * one extra fd */ |
56 | int FAST_FUNC udhcp_sp_fd_set(fd_set *rfds, int extra_fd) |
57 | { |
58 | FD_ZERO(rfds); |
59 | FD_SET(signal_pipe.rd, rfds); |
60 | if (extra_fd >= 0) { |
61 | close_on_exec_on(extra_fd); |
62 | FD_SET(extra_fd, rfds); |
63 | } |
64 | return signal_pipe.rd > extra_fd ? signal_pipe.rd : extra_fd; |
65 | } |
66 | |
67 | |
68 | /* Read a signal from the signal pipe. Returns 0 if there is |
69 | * no signal, -1 on error (and sets errno appropriately), and |
70 | * your signal on success */ |
71 | int FAST_FUNC udhcp_sp_read(const fd_set *rfds) |
72 | { |
73 | unsigned char sig; |
74 | |
75 | if (!FD_ISSET(signal_pipe.rd, rfds)) |
76 | return 0; |
77 | |
78 | if (safe_read(signal_pipe.rd, &sig, 1) != 1) |
79 | return -1; |
80 | |
81 | return sig; |
82 | } |