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pipe free fork is implemented (LTP fork09)

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This commit is contained in:
Tomoki Shirasawa
2015-03-04 17:40:58 +09:00
parent daec7de828
commit 9946ccd6b1
1 changed files with 140 additions and 96 deletions
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236
executer/user/mcexec.c
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@@ -55,6 +55,7 @@
#include <dirent.h>
#include <sys/syscall.h>
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include "../include/uprotocol.h"
@@ -120,6 +121,20 @@ static char *altroot;
static const char rlimit_stack_envname[] = "MCKERNEL_RLIMIT_STACK";
static int ischild;
struct fork_sync {
pid_t pid;
int status;
sem_t sem;
};
struct fork_sync_container {
struct fork_sync_container *next;
struct fork_sync *fs;
};
struct fork_sync_container *fork_sync_top;
pthread_mutex_t fork_sync_mutex = PTHREAD_MUTEX_INITIALIZER;
pid_t gettid(void)
{
return syscall(SYS_gettid);
@@ -1647,108 +1662,137 @@ int main_loop(int fd, int cpu, pthread_mutex_t *lock)
}
case __NR_fork: {
int child;
int sync_pipe_fd[2];
char sync_msg;
struct fork_sync *fs;
struct fork_sync_container *fsc;
struct fork_sync_container *fp;
struct fork_sync_container *fb;
int rc = -1;
pid_t pid;
if (pipe(sync_pipe_fd) != 0) {
fprintf(stderr, "fork(): error creating sync pipe\n");
do_syscall_return(fd, cpu, -1, 0, 0, 0, 0);
fsc = malloc(sizeof(struct fork_sync_container));
memset(fsc, '\0', sizeof(struct fork_sync_container));
pthread_mutex_lock(&fork_sync_mutex);
fsc->next = fork_sync_top;
fork_sync_top = fsc;
pthread_mutex_unlock(&fork_sync_mutex);
fsc->fs = fs = mmap(NULL, sizeof(struct fork_sync),
PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if(fs == (void *)-1){
goto fork_err;
}
memset(fs, '\0', sizeof(struct fork_sync));
sem_init(&fs->sem, 1, 0);
pid = fork();
switch (pid) {
/* Error */
case -1:
fprintf(stderr, "fork(): error forking child process\n");
rc = -errno;
break;
/* Child process */
case 0: {
int i;
int ret = 1;
struct newprocess_desc npdesc;
ischild = 1;
/* Reopen device fd */
close(fd);
fd = open(dev, O_RDWR);
if (fd < 0) {
fs->status = -errno;
fprintf(stderr, "ERROR: opening %s\n", dev);
goto fork_child_sync_pipe;
}
/* Reinit signals and syscall threads */
init_sigaction();
init_worker_threads(fd);
__dprintf("pid(%d): signals and syscall threads OK\n",
getpid());
/* Hold executable also in the child process */
if ((ret = ioctl(fd, MCEXEC_UP_OPEN_EXEC, exec_path))
!= 0) {
fprintf(stderr, "Error: open_exec() fails for %s: %d (fd: %d)\n",
exec_path, ret, fd);
fs->status = -errno;
goto fork_child_sync_pipe;
}
fork_child_sync_pipe:
sem_post(&fs->sem);
if (fs->status)
exit(1);
for (fp = fork_sync_top; fp;) {
fb = fp->next;
if (fp->fs)
munmap(fp->fs, sizeof(struct fork_sync));
free(fp);
fp = fb;
}
fork_sync_top = NULL;
pthread_mutex_init(&fork_sync_mutex, NULL);
npdesc.pid = getpid();
ioctl(fd, MCEXEC_UP_NEW_PROCESS, &npdesc);
/* TODO: does the forked thread run in a pthread context? */
for (i = 0; i <= ncpu; ++i) {
pthread_join(thread_data[i].thread_id, NULL);
}
return ret;
}
/* Parent */
default:
fs->pid = pid;
while ((rc = sem_trywait(&fs->sem)) == -1 && (errno == EAGAIN || errno == EINTR)) {
int st;
int wrc;
wrc = waitpid(pid, &st, WNOHANG);
if(wrc == pid) {
fs->status = -ENOMEM;
break;
}
sched_yield();
}
if (fs->status != 0) {
fprintf(stderr, "fork(): error with child process after fork\n");
rc = fs->status;
break;
}
rc = pid;
break;
}
child = fork();
switch (child) {
/* Error */
case -1:
fprintf(stderr, "fork(): error forking child process\n");
close(sync_pipe_fd[0]);
close(sync_pipe_fd[1]);
do_syscall_return(fd, cpu, -1, 0, 0, 0, 0);
break;
/* Child process */
case 0: {
int i;
int ret = 1;
struct newprocess_desc npdesc;
ischild = 1;
/* Reopen device fd */
close(fd);
fd = open(dev, O_RDWR);
if (fd < 0) {
/* TODO: tell parent something went wrong? */
fprintf(stderr, "ERROR: opening %s\n", dev);
/* Tell parent something went wrong */
sync_msg = 1;
goto fork_child_sync_pipe;
}
/* Reinit signals and syscall threads */
init_sigaction();
init_worker_threads(fd);
__dprintf("pid(%d): signals and syscall threads OK\n",
getpid());
/* Hold executable also in the child process */
if ((ret = ioctl(fd, MCEXEC_UP_OPEN_EXEC, exec_path))
!= 0) {
fprintf(stderr, "Error: open_exec() fails for %s: %d (fd: %d)\n",
exec_path, ret, fd);
goto fork_child_sync_pipe;
}
/* Tell parent everything went OK */
sync_msg = 0;
fork_child_sync_pipe:
if (write(sync_pipe_fd[1], &sync_msg, 1) != 1) {
fprintf(stderr, "ERROR: writing sync pipe\n");
goto fork_child_out;
}
ret = 0;
fork_child_out:
close(sync_pipe_fd[0]);
close(sync_pipe_fd[1]);
npdesc.pid = getpid();
ioctl(fd, MCEXEC_UP_NEW_PROCESS, &npdesc);
/* TODO: does the forked thread run in a pthread context? */
for (i = 0; i <= ncpu; ++i) {
pthread_join(thread_data[i].thread_id, NULL);
}
return ret;
}
/* Parent */
default:
while ((ret = read(sync_pipe_fd[0], &sync_msg, 1)) == -1 && errno == EINTR);
if (ret != 1) {
fprintf(stderr, "fork(): error reading sync message\n");
child = -1;
goto sync_out;
}
if (sync_msg != 0) {
fprintf(stderr, "fork(): error with child process after fork\n");
child = -1;
goto sync_out;
}
sync_out:
close(sync_pipe_fd[0]);
close(sync_pipe_fd[1]);
do_syscall_return(fd, cpu, child, 0, 0, 0, 0);
sem_destroy(&fs->sem);
munmap(fs, sizeof(struct fork_sync));
fork_err:
pthread_mutex_lock(&fork_sync_mutex);
for(fp = fork_sync_top, fb = NULL; fp; fb = fp, fp = fp->next)
if(fp == fsc)
break;
if(fp){
if(fb)
fb->next = fsc->next;
else
fork_sync_top = fsc->next;
}
pthread_mutex_unlock(&fork_sync_mutex);
do_syscall_return(fd, cpu, rc, 0, 0, 0, 0);
break;
}