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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2004 PathScale, Inc | |
3 | * Licensed under the GPL | |
4 | */ | |
5 | ||
6 | #include <signal.h> | |
0805d89c GS |
7 | #include <stdio.h> |
8 | #include <unistd.h> | |
9 | #include <stdlib.h> | |
10 | #include <errno.h> | |
11 | #include <stdarg.h> | |
12 | #include <string.h> | |
13 | #include <sys/mman.h> | |
14 | #include "user_util.h" | |
0805d89c GS |
15 | #include "user.h" |
16 | #include "signal_kern.h" | |
17 | #include "sysdep/sigcontext.h" | |
18 | #include "sysdep/signal.h" | |
19 | #include "sigcontext.h" | |
1da177e4 | 20 | #include "mode.h" |
cff65c4f | 21 | #include "os.h" |
1da177e4 | 22 | |
1d7173ba JD |
23 | /* These are the asynchronous signals. SIGVTALRM and SIGARLM are handled |
24 | * together under SIGVTALRM_BIT. SIGPROF is excluded because we want to | |
25 | * be able to profile all of UML, not just the non-critical sections. If | |
26 | * profiling is not thread-safe, then that is not my problem. We can disable | |
27 | * profiling when SMP is enabled in that case. | |
28 | */ | |
29 | #define SIGIO_BIT 0 | |
30 | #define SIGIO_MASK (1 << SIGIO_BIT) | |
31 | ||
32 | #define SIGVTALRM_BIT 1 | |
33 | #define SIGVTALRM_MASK (1 << SIGVTALRM_BIT) | |
34 | ||
35 | #define SIGALRM_BIT 2 | |
36 | #define SIGALRM_MASK (1 << SIGALRM_BIT) | |
37 | ||
38 | static int signals_enabled = 1; | |
39 | static int pending = 0; | |
40 | ||
51a6b0c5 | 41 | void sig_handler(ARCH_SIGHDLR_PARAM) |
1da177e4 LT |
42 | { |
43 | struct sigcontext *sc; | |
1d7173ba JD |
44 | int enabled; |
45 | ||
46 | /* Must be the first thing that this handler does - x86_64 stores | |
47 | * the sigcontext in %rdx, and we need to save it before it has a | |
48 | * chance to get trashed. | |
49 | */ | |
1da177e4 LT |
50 | |
51 | ARCH_GET_SIGCONTEXT(sc, sig); | |
1d7173ba JD |
52 | |
53 | enabled = signals_enabled; | |
54 | if(!enabled && (sig == SIGIO)){ | |
55 | pending |= SIGIO_MASK; | |
56 | return; | |
57 | } | |
58 | ||
59 | block_signals(); | |
60 | ||
1da177e4 LT |
61 | CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas, |
62 | sig, sc); | |
1d7173ba JD |
63 | |
64 | set_signals(enabled); | |
1da177e4 LT |
65 | } |
66 | ||
67 | extern int timer_irq_inited; | |
68 | ||
1d7173ba | 69 | static void real_alarm_handler(int sig, struct sigcontext *sc) |
1da177e4 | 70 | { |
1d7173ba JD |
71 | if(!timer_irq_inited){ |
72 | signals_enabled = 1; | |
73 | return; | |
74 | } | |
1da177e4 LT |
75 | |
76 | if(sig == SIGALRM) | |
77 | switch_timers(0); | |
78 | ||
79 | CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas, | |
80 | sig, sc); | |
81 | ||
82 | if(sig == SIGALRM) | |
83 | switch_timers(1); | |
1d7173ba JD |
84 | |
85 | } | |
86 | ||
87 | void alarm_handler(ARCH_SIGHDLR_PARAM) | |
88 | { | |
89 | struct sigcontext *sc; | |
90 | int enabled; | |
91 | ||
92 | ARCH_GET_SIGCONTEXT(sc, sig); | |
93 | ||
94 | enabled = signals_enabled; | |
95 | if(!signals_enabled){ | |
96 | if(sig == SIGVTALRM) | |
97 | pending |= SIGVTALRM_MASK; | |
98 | else pending |= SIGALRM_MASK; | |
99 | ||
100 | return; | |
101 | } | |
102 | ||
103 | block_signals(); | |
104 | ||
105 | real_alarm_handler(sig, sc); | |
106 | set_signals(enabled); | |
1da177e4 LT |
107 | } |
108 | ||
0805d89c GS |
109 | void set_sigstack(void *sig_stack, int size) |
110 | { | |
111 | stack_t stack = ((stack_t) { .ss_flags = 0, | |
112 | .ss_sp = (__ptr_t) sig_stack, | |
113 | .ss_size = size - sizeof(void *) }); | |
114 | ||
115 | if(sigaltstack(&stack, NULL) != 0) | |
116 | panic("enabling signal stack failed, errno = %d\n", errno); | |
117 | } | |
118 | ||
119 | void remove_sigstack(void) | |
120 | { | |
121 | stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE, | |
122 | .ss_sp = NULL, | |
123 | .ss_size = 0 }); | |
124 | ||
125 | if(sigaltstack(&stack, NULL) != 0) | |
126 | panic("disabling signal stack failed, errno = %d\n", errno); | |
127 | } | |
128 | ||
129 | void set_handler(int sig, void (*handler)(int), int flags, ...) | |
130 | { | |
131 | struct sigaction action; | |
132 | va_list ap; | |
1d7173ba | 133 | sigset_t sig_mask; |
0805d89c GS |
134 | int mask; |
135 | ||
136 | va_start(ap, flags); | |
137 | action.sa_handler = handler; | |
138 | sigemptyset(&action.sa_mask); | |
139 | while((mask = va_arg(ap, int)) != -1){ | |
140 | sigaddset(&action.sa_mask, mask); | |
141 | } | |
142 | va_end(ap); | |
143 | action.sa_flags = flags; | |
144 | action.sa_restorer = NULL; | |
145 | if(sigaction(sig, &action, NULL) < 0) | |
1d7173ba JD |
146 | panic("sigaction failed - errno = %d\n", errno); |
147 | ||
148 | sigemptyset(&sig_mask); | |
149 | sigaddset(&sig_mask, sig); | |
150 | if(sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0) | |
151 | panic("sigprocmask failed - errno = %d\n", errno); | |
0805d89c GS |
152 | } |
153 | ||
154 | int change_sig(int signal, int on) | |
155 | { | |
156 | sigset_t sigset, old; | |
157 | ||
158 | sigemptyset(&sigset); | |
159 | sigaddset(&sigset, signal); | |
160 | sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old); | |
161 | return(!sigismember(&old, signal)); | |
162 | } | |
163 | ||
0805d89c GS |
164 | void block_signals(void) |
165 | { | |
1d7173ba | 166 | signals_enabled = 0; |
0805d89c GS |
167 | } |
168 | ||
169 | void unblock_signals(void) | |
170 | { | |
1d7173ba | 171 | int save_pending; |
0805d89c | 172 | |
1d7173ba JD |
173 | if(signals_enabled == 1) |
174 | return; | |
0805d89c | 175 | |
1d7173ba JD |
176 | /* We loop because the IRQ handler returns with interrupts off. So, |
177 | * interrupts may have arrived and we need to re-enable them and | |
178 | * recheck pending. | |
179 | */ | |
180 | while(1){ | |
181 | /* Save and reset save_pending after enabling signals. This | |
182 | * way, pending won't be changed while we're reading it. | |
183 | */ | |
184 | signals_enabled = 1; | |
185 | ||
186 | save_pending = pending; | |
187 | if(save_pending == 0) | |
188 | return; | |
189 | ||
190 | pending = 0; | |
191 | ||
192 | /* We have pending interrupts, so disable signals, as the | |
193 | * handlers expect them off when they are called. They will | |
194 | * be enabled again above. | |
195 | */ | |
196 | ||
197 | signals_enabled = 0; | |
198 | ||
199 | /* Deal with SIGIO first because the alarm handler might | |
200 | * schedule, leaving the pending SIGIO stranded until we come | |
201 | * back here. | |
202 | */ | |
203 | if(save_pending & SIGIO_MASK) | |
204 | CHOOSE_MODE_PROC(sig_handler_common_tt, | |
205 | sig_handler_common_skas, SIGIO, NULL); | |
206 | ||
207 | if(save_pending & SIGALRM_MASK) | |
208 | real_alarm_handler(SIGALRM, NULL); | |
209 | ||
210 | if(save_pending & SIGVTALRM_MASK) | |
211 | real_alarm_handler(SIGVTALRM, NULL); | |
212 | } | |
0805d89c GS |
213 | } |
214 | ||
215 | int get_signals(void) | |
216 | { | |
1d7173ba | 217 | return signals_enabled; |
0805d89c GS |
218 | } |
219 | ||
220 | int set_signals(int enable) | |
221 | { | |
0805d89c | 222 | int ret; |
1d7173ba JD |
223 | if(signals_enabled == enable) |
224 | return enable; | |
0805d89c | 225 | |
1d7173ba JD |
226 | ret = signals_enabled; |
227 | if(enable) | |
228 | unblock_signals(); | |
229 | else block_signals(); | |
0805d89c | 230 | |
1d7173ba | 231 | return ret; |
0805d89c | 232 | } |
abaf6977 GS |
233 | |
234 | void os_usr1_signal(int on) | |
235 | { | |
236 | change_sig(SIGUSR1, on); | |
237 | } |