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signals.c
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signals.c
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/*
* Setup signals
*
* Copyright (C) 2014 - Brian Caswell <bmc@lungetech.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <err.h>
#include <signal.h>
#include <stdio.h>
#include <sys/wait.h>
#include <sys/resource.h>
#include <unistd.h>
#include <time.h>
#include <asm/unistd.h>
#include <linux/perf_event.h>
#include <string.h>
#include <sys/user.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include "utils.h"
#include "signals.h"
void sigchld(const int sig);
void sigterm(const int sig) __attribute__((noreturn));
extern unsigned long num_children;
extern int monitor_process;
unsigned long long sts_cpu_clock;
unsigned long long sts_task_clock;
long sts_maxrss;
long sts_minflt;
struct timeval sts_utime;
unsigned long sts_nkids;
int exit_val = 0;
void read_counters(pid_t pid);
void print_registers(pid_t pid);
struct cntr_desc {
__u32 type;
__u32 config;
const char *name;
unsigned long long *val;
} cntr_desc[] = {
{ PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK,
"sw-cpu-clock", &sts_cpu_clock },
{ PERF_TYPE_SOFTWARE, PERF_COUNT_SW_TASK_CLOCK,
"sw-task-clock", &sts_task_clock },
};
#define NCNTRS_PER_PROC (sizeof(cntr_desc) / sizeof(cntr_desc[0]))
struct cntr {
pid_t pid;
const struct cntr_desc *desc;
int fd;
} *cntrs = NULL;
int ncntrs = 0;
void sigchld(const int sig) {
int status;
pid_t pid;
struct rusage ru;
/* unused argument */
(void) sig;
int signum;
while ((pid = wait4(-1, &status, WNOHANG, &ru)) > 0) {
signum = 0;
if (WIFEXITED(status)) {
printf("CB exited (pid: %d, exit code: %d)\n", pid, WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
signum = WTERMSIG(status);
// printf("SIGNALED %d\n", signum);
} else if (WIFSTOPPED(status)) {
signum = WSTOPSIG(status);
// printf("STOPPED %d\n", signum);
if (signum == SIGPIPE) {
// printf("continuing on SIGPIPE\n");
ptrace(PT_CONTINUE, pid, (caddr_t)1, signum);
continue;
}
}
switch (signum) {
case 0:
case SIGUSR1:
/* exited normally */
break;
case SIGALRM:
if (monitor_process == 1)
printf("CB timed out (pid: %d)\n", pid);
if (exit_val == 0) {
exit_val = -signum;
}
break;
case SIGSEGV:
case SIGILL:
case SIGBUS:
print_registers(pid);
default:
if (monitor_process == 1)
printf("CB generated signal (pid: %d, signal: %d)\n", pid, signum);
if (exit_val == 0) {
exit_val = -signum;
}
break;
}
ptrace(PT_DETACH, pid, 0, 0);
if (signum == 0)
signum = SIGUSR1;
kill(pid, signum);
/* save off the stats */
sts_minflt += ru.ru_minflt;
sts_maxrss += ru.ru_maxrss;
sts_utime.tv_sec += ru.ru_utime.tv_sec;
sts_utime.tv_usec += ru.ru_utime.tv_usec;
while (sts_utime.tv_usec >= 1000000) {
sts_utime.tv_sec += 1;
sts_utime.tv_usec -= 1000000;
}
sts_nkids++;
read_counters(pid);
if (num_children)
num_children--;
}
}
void sigterm(const int sig) {
(void) sig;
_exit(0);
}
void setup_signals(void) {
sigset_t blocked_set;
struct sigaction setup_action;
sigemptyset(&blocked_set);
sigaddset(&blocked_set, SIGCHLD);
setup_action.sa_handler = sigchld;
setup_action.sa_mask = blocked_set;
setup_action.sa_flags = 0;
VERIFY(sigaction, SIGCHLD, &setup_action, NULL);
sigprocmask(SIG_BLOCK, &blocked_set, NULL);
if (signal(SIGUSR1, SIG_IGN) == SIG_ERR)
err(-1, "signal(SIGINFO) failed");
}
void unsetup_signals(void) {
if (signal(SIGCHLD, SIG_DFL) == SIG_ERR)
err(-1, "signal(SIGCHLD) failed");
if (signal(SIGUSR1, SIG_DFL) == SIG_ERR)
err(-1, "signal(SIGINFO) failed");
}
void handle_blocked_children(void) {
sigset_t blocked_set;
sigemptyset(&blocked_set);
sigaddset(&blocked_set, SIGCHLD);
sigprocmask(SIG_UNBLOCK, &blocked_set, NULL);
/* if we had any SIGCHLD waiting, we should hit it... now */
sigprocmask(SIG_BLOCK, &blocked_set, NULL);
}
void wait_for_signal(void) {
sigset_t empty_set;
sigemptyset(&empty_set);
if (exit_val < 0) {
kill(-getpid(), SIGUSR1);
}
sigsuspend(&empty_set);
}
void setup_ptrace(pid_t pid) {
int status;
if (ptrace(PT_ATTACH, pid, 0, 0) != 0) {
err(-1, "ptrace attach failed");
}
if (waitpid(pid, &status, 0) == pid) {
if (WIFSTOPPED(status)) {
if (WSTOPSIG(status) == SIGSTOP) {
if (ptrace(PT_CONTINUE, pid, (caddr_t)1, 0) != 0) {
err(-1, "ptrace continue failed");
}
return;
}
}
err(-1, "unexpected waitpid status: %d\n", status);
}
}
void continue_ptrace(pid_t pid) {
int status;
if (waitpid(pid, &status, 0) == pid) {
if (WIFSTOPPED(status)) {
if (WSTOPSIG(status) == SIGTRAP) {
if (ptrace(PT_CONTINUE, pid, (caddr_t)1, 0) != 0) {
err(-1, "ptrace continue failed");
}
return;
}
}
err(-1, "unexpected waitpid status (continue): %d\n", status);
}
}
void print_registers(pid_t pid) {
int res;
struct user_regs_struct registers;
res = ptrace(PT_GETREGS, pid, 0, (caddr_t)®isters);
if (res == 0) {
printf("register states - ");
printf("eax: %08lx ", registers.eax);
printf("ecx: %08lx ", registers.ecx);
printf("edx: %08lx ", registers.edx);
printf("ebx: %08lx ", registers.ebx);
printf("esp: %08lx ", registers.esp);
printf("ebp: %08lx ", registers.ebp);
printf("esi: %08lx ", registers.esi);
printf("edi: %08lx ", registers.edi);
printf("eip: %08lx\n", registers.eip);
fflush(stdout);
}
}
void show_perf_stats(void) {
int i;
printf("total children: %lu\n", sts_nkids);
printf("total maxrss %ld\n", sts_maxrss);
printf("total minflt %ld\n", sts_minflt);
printf("total utime %lu.%06lu\n", (unsigned long)sts_utime.tv_sec,
(unsigned long)sts_utime.tv_usec);
for (i = 0; i < NCNTRS_PER_PROC; i++)
printf("total %s %llu\n", cntr_desc[i].name, *cntr_desc[i].val);
fflush(stdout);
}
static int perf_event_open(struct perf_event_attr *event, pid_t pid, int cpu,
int groupfd, unsigned long flags) {
return syscall(__NR_perf_event_open, event, pid, cpu, groupfd, flags);
}
int make_counter(struct cntr *cntr, const struct cntr_desc *desc, pid_t pid,
int gfd) {
struct perf_event_attr attr;
memset(&attr, 0, sizeof(attr));
attr.type = desc->type;
attr.size = sizeof(attr);
attr.config = desc->config;
attr.disabled = 1;
attr.exclude_idle = 1;
attr.exclude_kernel = 1;
attr.exclude_hv = 1;
attr.enable_on_exec = 1;
if ((cntr->fd = perf_event_open(&attr, pid, -1, gfd, 0)) == -1)
err(-1, "perf_event_open");
cntr->desc = desc;
cntr->pid = pid;
return (cntr->fd);
}
void zero_perf_stats(int nprocs) {
int i;
sts_utime.tv_sec = 0;
sts_utime.tv_usec = 0;
sts_nkids = 0;
sts_maxrss = 0;
sts_minflt = 0;
ncntrs = nprocs * NCNTRS_PER_PROC;
cntrs = (struct cntr *)calloc(ncntrs, sizeof(*cntrs));
for (i = 0; i < NCNTRS_PER_PROC; i++)
*cntr_desc[i].val = 0ULL;
}
void setup_counters(int procno, pid_t pid) {
int grp = -1, i, fd;
struct cntr *cntr = &cntrs[procno * NCNTRS_PER_PROC];
for (i = 0; i < NCNTRS_PER_PROC; i++) {
fd = make_counter(cntr + i, &cntr_desc[i], pid, grp);
if (grp == -1)
grp = fd;
}
}
void read_counters(pid_t pid) {
int i;
for (i = 0; i < ncntrs; i++) {
unsigned long long ct;
if (cntrs[i].pid != pid)
continue;
if (read(cntrs[i].fd, &ct, sizeof(ct)) != sizeof(ct))
continue;
*cntrs[i].desc->val += ct;
}
}
/* Local variables: */
/* mode: c */
/* c-basic-offset: 4 */
/* End: */