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/*
* Each process that gets forked runs this code.
*/
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sched.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/prctl.h>
#include "child.h"
#include "list.h"
#include "log.h"
#include "maps.h"
#include "params.h" // for 'debug'
#include "pids.h"
#include "random.h"
#include "shm.h"
#include "signals.h"
#include "syscall.h"
#include "tables.h"
#include "trinity.h" // ARRAY_SIZE
#include "utils.h" // zmalloc
static struct rlimit oldrlimit;
static void disable_coredumps(void)
{
struct rlimit limit;
if (debug == TRUE) {
(void)signal(SIGSEGV, SIG_DFL);
return;
}
getrlimit(RLIMIT_CORE, &oldrlimit);
limit.rlim_cur = 0;
limit.rlim_max = oldrlimit.rlim_max;
if (setrlimit(RLIMIT_CORE, &limit) != 0)
perror( "setrlimit(RLIMIT_CORE)" );
}
static void reenable_coredumps(void)
{
if (debug == TRUE)
return;
prctl(PR_SET_DUMPABLE, TRUE);
if (setrlimit(RLIMIT_CORE, &oldrlimit) != 0) {
outputerr("[%d] Error restoring rlimits to cur:%d max:%d (%s)\n",
getpid(),
(unsigned int) oldrlimit.rlim_cur,
(unsigned int) oldrlimit.rlim_max,
strerror(errno));
}
}
static void set_make_it_fail(void)
{
int fd;
const char *buf = "1";
/* If we failed last time, don't bother trying in future. */
if (shm->do_make_it_fail == TRUE)
return;
fd = open("/proc/self/make-it-fail", O_WRONLY);
if (fd == -1)
return;
if (write(fd, buf, 1) == -1) {
if (errno != EPERM)
outputerr("writing to /proc/self/make-it-fail failed! (%s)\n", strerror(errno));
else
shm->do_make_it_fail = TRUE;
}
close(fd);
}
/*
* We call this occasionally to set some FPU state, in the hopes that we
* might tickle some weird FPU/scheduler related bugs
*/
static void use_fpu(void)
{
double x = 0;
asm volatile("":"+m" (x));
x += 1;
asm volatile("":"+m" (x));
}
int this_child = 0;
void init_child(int childno)
{
cpu_set_t set;
pid_t pid = getpid();
this_child = childno;
set_seed(childno);
shm->kill_count[childno] = 0;
disable_coredumps();
if (sched_getaffinity(pid, sizeof(set), &set) == 0) {
CPU_ZERO(&set);
CPU_SET(childno, &set);
sched_setaffinity(pid, sizeof(set), &set);
}
shm->child_syscall_count[childno] = 0;
set_make_it_fail();
if (rand() % 100 < 50)
use_fpu();
shm->num_mappings[childno] = 0;
shm->mappings[childno] = zmalloc(sizeof(struct map));
INIT_LIST_HEAD(&shm->mappings[childno]->list);
}
void check_parent_pid(void)
{
pid_t pid;
unsigned int i;
static unsigned int parent_check_time = 10;
parent_check_time--;
if (parent_check_time != 0)
return;
parent_check_time = 10;
if (getppid() == shm->mainpid)
return;
pid = getpid();
//FIXME: Add locking so only one child does this output.
output(0, BUGTXT "CHILD (pid:%d) GOT REPARENTED! "
"parent pid:%d. Watchdog pid:%d\n",
pid, shm->mainpid, watchdog_pid);
output(0, BUGTXT "Last syscalls:\n");
for (i = 0; i < MAX_NR_CHILDREN; i++) {
// Skip over 'boring' entries.
if ((shm->pids[i] == -1) &&
(shm->previous_syscallno[i] == 0) &&
(shm->child_syscall_count[i] == 0))
continue;
output(0, "[%d] pid:%d call:%s callno:%d\n",
i, shm->pids[i],
print_syscall_name(shm->previous_syscallno[i], shm->do32bit[i]), // FIXME: need previous do32bit
shm->child_syscall_count[i]);
}
shm->exit_reason = EXIT_REPARENT_PROBLEM;
exit(EXIT_FAILURE);
//TODO: Emergency logging.
}
struct child_funcs {
int type;
const char *name;
int (*func)(int childno);
};
static const struct child_funcs child_functions[] = {
{ .type = CHILD_RANDOM_SYSCALLS, .name = "rand_syscalls", .func = child_random_syscalls },
#ifdef DEBUG_MULTI
{ .type = CHILD_OPEN_ALL_FILES, .name = "read_all_files", .func = child_read_all_files },
#endif
};
int child_process(int childno)
{
int ret;
unsigned int i;
i = rand() % ARRAY_SIZE(child_functions);
#ifdef DEBUG_MULTI
output(0, "Chose %s.\n", child_functions[i].name);
#endif
shm->child_type[childno] = child_functions[i].type;
ret = child_functions[i].func(childno);
reenable_coredumps();
return ret;
}
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