int main(int argc, char **argv)
{
pid_t pid;
pid = fork();
if (pid == -1) {
perror("fork");
exit(EXIT_FAILURE);
} else if (pid == 0) {
// クライアント(子プロセス)
int shmfd;
// Unix ドメインクライントを作り shmfd を受信
shmfd = do_client();
// shmfd を使って mmap() を行い共有メモリに書き込み
void *addr;
addr = mmap(NULL, TEMPFILE_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, shmfd, 0);
if (addr == MAP_FAILED) {
perror("mmap");
exit(EXIT_FAILURE);
}
sprintf((char*)addr, "ABCDEFG");
close(shmfd);
} else {
// サーバー(親プロセス)
// 共有ファイルの file descriptor を取得
int shmfd;
shmfd = create_shm_file();
// Unix ドメインサーバを作り shmfd を送信
do_server(shmfd);
// 子プロセスの終了を待つ
if (waitpid(pid, NULL, 0) == -1) {
perror("waitpid");
exit(EXIT_FAILURE);
}
// shmfd を使って mmap() を行い共有メモリの内容を表示
void *addr;
addr = mmap(NULL, TEMPFILE_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, shmfd, 0);
if (addr == MAP_FAILED) {
perror("mmap");
exit(EXIT_FAILURE);
}
close(shmfd);
// 子プロセスが書き込んだ内容が見えれば成功
puts((const char*)addr);
}
return 0;
}
/* Open the shared memory segment *R_KEY and return a file descriptor
to it in R_FD. If KEY is IPC_PRIVATE, use a private key and return
it in R_KEY. */
static error_t
get_exclusive (int shmflags, size_t size, key_t *r_key, int *r_fd)
{
error_t err;
file_t dir;
file_t file;
char filename[SHM_NAMEMAX];
key_t key = *r_key;
bool is_private;
/* Create the shared memory segment. */
err = create_shm_file (size, shmflags, &dir, &file);
if (err)
return err;
if (key == IPC_PRIVATE)
{
is_private = true;
key = SHM_PRIV_KEY_START;
/* Try to link the shared memory segment into the filesystem
(exclusively). Private segments have negative keys. */
do
{
sprintf (filename, SHM_NAMEPRI, key);
err = __dir_link (dir, file, filename, 1);
if (!err)
{
/* We are done. */
*r_key = key;
break;
}
else if (err == EEXIST)
{
/* Check if we ran out of keys. If not, try again with new
key. */
if (key == SHM_PRIV_KEY_END)
err = ENOSPC;
else
err = 0;
key--;
}
}
while (!err);
}
else
{
/* Try to link the shared memory segment into the filesystem
(exclusively) under the given key. */
sprintf (filename, SHM_NAMEPRI, key);
err = __dir_link (dir, file, filename, 1);
}
__mach_port_deallocate (__mach_task_self (), dir);
if (!err)
{
int fd;
/* Get a file descriptor for that port. */
fd = _hurd_intern_fd (file, O_RDWR, 1); /* dealloc on error */
if (fd < 0)
err = errno;
else
*r_fd = fd;
}
return err;
}