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1da177e4 LT |
1 | /* |
2 | * linux/kernel/itimer.c | |
3 | * | |
4 | * Copyright (C) 1992 Darren Senn | |
5 | */ | |
6 | ||
7 | /* These are all the functions necessary to implement itimers */ | |
8 | ||
9 | #include <linux/mm.h> | |
10 | #include <linux/smp_lock.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/syscalls.h> | |
13 | #include <linux/time.h> | |
14 | #include <linux/posix-timers.h> | |
15 | ||
16 | #include <asm/uaccess.h> | |
17 | ||
18 | static unsigned long it_real_value(struct signal_struct *sig) | |
19 | { | |
20 | unsigned long val = 0; | |
21 | if (timer_pending(&sig->real_timer)) { | |
22 | val = sig->real_timer.expires - jiffies; | |
23 | ||
24 | /* look out for negative/zero itimer.. */ | |
25 | if ((long) val <= 0) | |
26 | val = 1; | |
27 | } | |
28 | return val; | |
29 | } | |
30 | ||
31 | int do_getitimer(int which, struct itimerval *value) | |
32 | { | |
33 | struct task_struct *tsk = current; | |
34 | unsigned long interval, val; | |
35 | cputime_t cinterval, cval; | |
36 | ||
37 | switch (which) { | |
38 | case ITIMER_REAL: | |
39 | spin_lock_irq(&tsk->sighand->siglock); | |
40 | interval = tsk->signal->it_real_incr; | |
41 | val = it_real_value(tsk->signal); | |
42 | spin_unlock_irq(&tsk->sighand->siglock); | |
43 | jiffies_to_timeval(val, &value->it_value); | |
44 | jiffies_to_timeval(interval, &value->it_interval); | |
45 | break; | |
46 | case ITIMER_VIRTUAL: | |
47 | read_lock(&tasklist_lock); | |
48 | spin_lock_irq(&tsk->sighand->siglock); | |
49 | cval = tsk->signal->it_virt_expires; | |
50 | cinterval = tsk->signal->it_virt_incr; | |
51 | if (!cputime_eq(cval, cputime_zero)) { | |
52 | struct task_struct *t = tsk; | |
53 | cputime_t utime = tsk->signal->utime; | |
54 | do { | |
55 | utime = cputime_add(utime, t->utime); | |
56 | t = next_thread(t); | |
57 | } while (t != tsk); | |
58 | if (cputime_le(cval, utime)) { /* about to fire */ | |
59 | cval = jiffies_to_cputime(1); | |
60 | } else { | |
61 | cval = cputime_sub(cval, utime); | |
62 | } | |
63 | } | |
64 | spin_unlock_irq(&tsk->sighand->siglock); | |
65 | read_unlock(&tasklist_lock); | |
66 | cputime_to_timeval(cval, &value->it_value); | |
67 | cputime_to_timeval(cinterval, &value->it_interval); | |
68 | break; | |
69 | case ITIMER_PROF: | |
70 | read_lock(&tasklist_lock); | |
71 | spin_lock_irq(&tsk->sighand->siglock); | |
72 | cval = tsk->signal->it_prof_expires; | |
73 | cinterval = tsk->signal->it_prof_incr; | |
74 | if (!cputime_eq(cval, cputime_zero)) { | |
75 | struct task_struct *t = tsk; | |
76 | cputime_t ptime = cputime_add(tsk->signal->utime, | |
77 | tsk->signal->stime); | |
78 | do { | |
79 | ptime = cputime_add(ptime, | |
80 | cputime_add(t->utime, | |
81 | t->stime)); | |
82 | t = next_thread(t); | |
83 | } while (t != tsk); | |
84 | if (cputime_le(cval, ptime)) { /* about to fire */ | |
85 | cval = jiffies_to_cputime(1); | |
86 | } else { | |
87 | cval = cputime_sub(cval, ptime); | |
88 | } | |
89 | } | |
90 | spin_unlock_irq(&tsk->sighand->siglock); | |
91 | read_unlock(&tasklist_lock); | |
92 | cputime_to_timeval(cval, &value->it_value); | |
93 | cputime_to_timeval(cinterval, &value->it_interval); | |
94 | break; | |
95 | default: | |
96 | return(-EINVAL); | |
97 | } | |
98 | return 0; | |
99 | } | |
100 | ||
101 | asmlinkage long sys_getitimer(int which, struct itimerval __user *value) | |
102 | { | |
103 | int error = -EFAULT; | |
104 | struct itimerval get_buffer; | |
105 | ||
106 | if (value) { | |
107 | error = do_getitimer(which, &get_buffer); | |
108 | if (!error && | |
109 | copy_to_user(value, &get_buffer, sizeof(get_buffer))) | |
110 | error = -EFAULT; | |
111 | } | |
112 | return error; | |
113 | } | |
114 | ||
115 | /* | |
116 | * Called with P->sighand->siglock held and P->signal->real_timer inactive. | |
117 | * If interval is nonzero, arm the timer for interval ticks from now. | |
118 | */ | |
119 | static inline void it_real_arm(struct task_struct *p, unsigned long interval) | |
120 | { | |
121 | p->signal->it_real_value = interval; /* XXX unnecessary field?? */ | |
122 | if (interval == 0) | |
123 | return; | |
124 | if (interval > (unsigned long) LONG_MAX) | |
125 | interval = LONG_MAX; | |
b7e4e853 PM |
126 | /* the "+ 1" below makes sure that the timer doesn't go off before |
127 | * the interval requested. This could happen if | |
128 | * time requested % (usecs per jiffy) is more than the usecs left | |
129 | * in the current jiffy */ | |
130 | p->signal->real_timer.expires = jiffies + interval + 1; | |
1da177e4 LT |
131 | add_timer(&p->signal->real_timer); |
132 | } | |
133 | ||
134 | void it_real_fn(unsigned long __data) | |
135 | { | |
136 | struct task_struct * p = (struct task_struct *) __data; | |
137 | ||
138 | send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p); | |
139 | ||
140 | /* | |
141 | * Now restart the timer if necessary. We don't need any locking | |
142 | * here because do_setitimer makes sure we have finished running | |
143 | * before it touches anything. | |
144 | */ | |
145 | it_real_arm(p, p->signal->it_real_incr); | |
146 | } | |
147 | ||
148 | int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) | |
149 | { | |
150 | struct task_struct *tsk = current; | |
151 | unsigned long val, interval; | |
152 | cputime_t cval, cinterval, nval, ninterval; | |
153 | ||
154 | switch (which) { | |
155 | case ITIMER_REAL: | |
f01b1b0b | 156 | again: |
1da177e4 LT |
157 | spin_lock_irq(&tsk->sighand->siglock); |
158 | interval = tsk->signal->it_real_incr; | |
159 | val = it_real_value(tsk->signal); | |
f01b1b0b ON |
160 | /* We are sharing ->siglock with it_real_fn() */ |
161 | if (try_to_del_timer_sync(&tsk->signal->real_timer) < 0) { | |
162 | spin_unlock_irq(&tsk->sighand->siglock); | |
163 | goto again; | |
164 | } | |
1da177e4 LT |
165 | tsk->signal->it_real_incr = |
166 | timeval_to_jiffies(&value->it_interval); | |
167 | it_real_arm(tsk, timeval_to_jiffies(&value->it_value)); | |
168 | spin_unlock_irq(&tsk->sighand->siglock); | |
169 | if (ovalue) { | |
170 | jiffies_to_timeval(val, &ovalue->it_value); | |
171 | jiffies_to_timeval(interval, | |
172 | &ovalue->it_interval); | |
173 | } | |
174 | break; | |
175 | case ITIMER_VIRTUAL: | |
176 | nval = timeval_to_cputime(&value->it_value); | |
177 | ninterval = timeval_to_cputime(&value->it_interval); | |
178 | read_lock(&tasklist_lock); | |
179 | spin_lock_irq(&tsk->sighand->siglock); | |
180 | cval = tsk->signal->it_virt_expires; | |
181 | cinterval = tsk->signal->it_virt_incr; | |
182 | if (!cputime_eq(cval, cputime_zero) || | |
183 | !cputime_eq(nval, cputime_zero)) { | |
184 | if (cputime_gt(nval, cputime_zero)) | |
185 | nval = cputime_add(nval, | |
186 | jiffies_to_cputime(1)); | |
187 | set_process_cpu_timer(tsk, CPUCLOCK_VIRT, | |
188 | &nval, &cval); | |
189 | } | |
190 | tsk->signal->it_virt_expires = nval; | |
191 | tsk->signal->it_virt_incr = ninterval; | |
192 | spin_unlock_irq(&tsk->sighand->siglock); | |
193 | read_unlock(&tasklist_lock); | |
194 | if (ovalue) { | |
195 | cputime_to_timeval(cval, &ovalue->it_value); | |
196 | cputime_to_timeval(cinterval, &ovalue->it_interval); | |
197 | } | |
198 | break; | |
199 | case ITIMER_PROF: | |
200 | nval = timeval_to_cputime(&value->it_value); | |
201 | ninterval = timeval_to_cputime(&value->it_interval); | |
202 | read_lock(&tasklist_lock); | |
203 | spin_lock_irq(&tsk->sighand->siglock); | |
204 | cval = tsk->signal->it_prof_expires; | |
205 | cinterval = tsk->signal->it_prof_incr; | |
206 | if (!cputime_eq(cval, cputime_zero) || | |
207 | !cputime_eq(nval, cputime_zero)) { | |
208 | if (cputime_gt(nval, cputime_zero)) | |
209 | nval = cputime_add(nval, | |
210 | jiffies_to_cputime(1)); | |
211 | set_process_cpu_timer(tsk, CPUCLOCK_PROF, | |
212 | &nval, &cval); | |
213 | } | |
214 | tsk->signal->it_prof_expires = nval; | |
215 | tsk->signal->it_prof_incr = ninterval; | |
216 | spin_unlock_irq(&tsk->sighand->siglock); | |
217 | read_unlock(&tasklist_lock); | |
218 | if (ovalue) { | |
219 | cputime_to_timeval(cval, &ovalue->it_value); | |
220 | cputime_to_timeval(cinterval, &ovalue->it_interval); | |
221 | } | |
222 | break; | |
223 | default: | |
224 | return -EINVAL; | |
225 | } | |
226 | return 0; | |
227 | } | |
228 | ||
229 | asmlinkage long sys_setitimer(int which, | |
230 | struct itimerval __user *value, | |
231 | struct itimerval __user *ovalue) | |
232 | { | |
233 | struct itimerval set_buffer, get_buffer; | |
234 | int error; | |
235 | ||
236 | if (value) { | |
237 | if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) | |
238 | return -EFAULT; | |
239 | } else | |
240 | memset((char *) &set_buffer, 0, sizeof(set_buffer)); | |
241 | ||
242 | error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); | |
243 | if (error || !ovalue) | |
244 | return error; | |
245 | ||
246 | if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) | |
247 | return -EFAULT; | |
248 | return 0; | |
249 | } |