Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
Paulo Marques | b7e4e85 | 2005-05-05 16:15:49 -0700 | [diff] [blame] | 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; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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: |
| 156 | spin_lock_irq(&tsk->sighand->siglock); |
| 157 | interval = tsk->signal->it_real_incr; |
| 158 | val = it_real_value(tsk->signal); |
| 159 | if (val) |
| 160 | del_timer_sync(&tsk->signal->real_timer); |
| 161 | tsk->signal->it_real_incr = |
| 162 | timeval_to_jiffies(&value->it_interval); |
| 163 | it_real_arm(tsk, timeval_to_jiffies(&value->it_value)); |
| 164 | spin_unlock_irq(&tsk->sighand->siglock); |
| 165 | if (ovalue) { |
| 166 | jiffies_to_timeval(val, &ovalue->it_value); |
| 167 | jiffies_to_timeval(interval, |
| 168 | &ovalue->it_interval); |
| 169 | } |
| 170 | break; |
| 171 | case ITIMER_VIRTUAL: |
| 172 | nval = timeval_to_cputime(&value->it_value); |
| 173 | ninterval = timeval_to_cputime(&value->it_interval); |
| 174 | read_lock(&tasklist_lock); |
| 175 | spin_lock_irq(&tsk->sighand->siglock); |
| 176 | cval = tsk->signal->it_virt_expires; |
| 177 | cinterval = tsk->signal->it_virt_incr; |
| 178 | if (!cputime_eq(cval, cputime_zero) || |
| 179 | !cputime_eq(nval, cputime_zero)) { |
| 180 | if (cputime_gt(nval, cputime_zero)) |
| 181 | nval = cputime_add(nval, |
| 182 | jiffies_to_cputime(1)); |
| 183 | set_process_cpu_timer(tsk, CPUCLOCK_VIRT, |
| 184 | &nval, &cval); |
| 185 | } |
| 186 | tsk->signal->it_virt_expires = nval; |
| 187 | tsk->signal->it_virt_incr = ninterval; |
| 188 | spin_unlock_irq(&tsk->sighand->siglock); |
| 189 | read_unlock(&tasklist_lock); |
| 190 | if (ovalue) { |
| 191 | cputime_to_timeval(cval, &ovalue->it_value); |
| 192 | cputime_to_timeval(cinterval, &ovalue->it_interval); |
| 193 | } |
| 194 | break; |
| 195 | case ITIMER_PROF: |
| 196 | nval = timeval_to_cputime(&value->it_value); |
| 197 | ninterval = timeval_to_cputime(&value->it_interval); |
| 198 | read_lock(&tasklist_lock); |
| 199 | spin_lock_irq(&tsk->sighand->siglock); |
| 200 | cval = tsk->signal->it_prof_expires; |
| 201 | cinterval = tsk->signal->it_prof_incr; |
| 202 | if (!cputime_eq(cval, cputime_zero) || |
| 203 | !cputime_eq(nval, cputime_zero)) { |
| 204 | if (cputime_gt(nval, cputime_zero)) |
| 205 | nval = cputime_add(nval, |
| 206 | jiffies_to_cputime(1)); |
| 207 | set_process_cpu_timer(tsk, CPUCLOCK_PROF, |
| 208 | &nval, &cval); |
| 209 | } |
| 210 | tsk->signal->it_prof_expires = nval; |
| 211 | tsk->signal->it_prof_incr = ninterval; |
| 212 | spin_unlock_irq(&tsk->sighand->siglock); |
| 213 | read_unlock(&tasklist_lock); |
| 214 | if (ovalue) { |
| 215 | cputime_to_timeval(cval, &ovalue->it_value); |
| 216 | cputime_to_timeval(cinterval, &ovalue->it_interval); |
| 217 | } |
| 218 | break; |
| 219 | default: |
| 220 | return -EINVAL; |
| 221 | } |
| 222 | return 0; |
| 223 | } |
| 224 | |
| 225 | asmlinkage long sys_setitimer(int which, |
| 226 | struct itimerval __user *value, |
| 227 | struct itimerval __user *ovalue) |
| 228 | { |
| 229 | struct itimerval set_buffer, get_buffer; |
| 230 | int error; |
| 231 | |
| 232 | if (value) { |
| 233 | if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) |
| 234 | return -EFAULT; |
| 235 | } else |
| 236 | memset((char *) &set_buffer, 0, sizeof(set_buffer)); |
| 237 | |
| 238 | error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); |
| 239 | if (error || !ovalue) |
| 240 | return error; |
| 241 | |
| 242 | if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) |
| 243 | return -EFAULT; |
| 244 | return 0; |
| 245 | } |