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safe_fork_helper.h
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246 lines (219 loc) · 5.3 KB
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#ifndef _SAFE_FORK_HELPER_H_
#define _SAFE_FORK_HELPER_H_
#include <string.h>
#include <iostream>
#include <fstream>
#include <memory>
#include <vector>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
class fork_base_info {
public:
fork_base_info() { reset(); }
~fork_base_info() { close(); }
int fd_read = -1;
int fd_write = -1;
pid_t pid = 0;
void reset() {
close();
fd_read = -1;
fd_write = -1;
pid = 0;
}
void close() {
if (fd_read != -1) {
::close(fd_read);
fd_read = -1;
}
if (fd_write != -1) {
::close(fd_write);
fd_write = -1;
}
}
};
class fork_pipe_info : public fork_base_info {};
static bool fork_pipe_child_process(fork_pipe_info & finfo) {
int fd[2];
if (pipe(fd)) {
return false;
}
pid_t pid;
if ((pid = fork()) < 0) {
//fork error
return false;
}
finfo.pid = pid;
if(pid == 0) { // child process
close(fd[0]); //close read pipe
finfo.fd_read = -1;
finfo.fd_write = fd[1];
return true;
}
// father process
close(fd[1]); //close write pipe
finfo.fd_read = fd[0];
finfo.fd_write = -1;
return false;
}
static bool wait_fork_child_process(const fork_base_info & finfo) {
if(finfo.pid == 0) {
return false;
}
int status;
if (waitpid(finfo.pid, &status, WUNTRACED) < 0) {
return false;
}
return true;
}
static bool write_errcode_to_father(const fork_pipe_info & finfo, ssize_t errCode) {
if(write(finfo.fd_write, &errCode, sizeof(errCode))==sizeof(errCode)) {
return true;
}
return false;
}
static bool read_errcode_from_child(const fork_pipe_info & finfo, ssize_t & errCode) {
if(read(finfo.fd_read, (void*)&errCode, sizeof(errCode))==sizeof(errCode)) {
return true;
}
return false;
}
static bool write_int_to_father(const fork_pipe_info & finfo, int n) {
if(write(finfo.fd_write, &n, sizeof(n))==sizeof(n)) {
return true;
}
return false;
}
static bool read_int_from_child(const fork_pipe_info & finfo, int & n) {
if(read(finfo.fd_read, (void*)&n, sizeof(n))==sizeof(n)) {
return true;
}
return false;
}
static bool write_vec_int_to_father(const fork_pipe_info & finfo, const std::vector<int> & v) {
size_t len = v.size();
if(write(finfo.fd_write, &len, sizeof(len))!=sizeof(len)) {
return false;
}
for(int i : v) {
if(write(finfo.fd_write, &i, sizeof(i))!=sizeof(i)) {
return false;
}
}
return true;
}
static bool read_vec_int_from_child(const fork_pipe_info & finfo, std::vector<int> & v) {
size_t len = 0;
if(read(finfo.fd_read, (void*)&len, sizeof(len))!=sizeof(len)) {
return false;
}
for(size_t i = 0; i < len; i++) {
int n = 0;
if(read(finfo.fd_read, (void*)&n, sizeof(n))!=sizeof(n)) {
return false;
}
v.push_back(n);
}
return true;
}
static bool write_string_to_father(const fork_pipe_info & finfo, const std::string &text) {
size_t len = text.length();
if(write(finfo.fd_write, &len, sizeof(len))!=sizeof(len)) {
return false;
}
if(write(finfo.fd_write, text.c_str(), len)!=len) {
return false;
}
return true;
}
static bool read_string_from_child(const fork_pipe_info & finfo, std::string &text) {
size_t len = 0;
if(read(finfo.fd_read, (void*)&len, sizeof(len))!=sizeof(len)) {
return false;
}
std::shared_ptr<char> sp_buf(new (std::nothrow) char[len], std::default_delete<char[]>());
if (!sp_buf) {
return false;
}
if(read(finfo.fd_read, sp_buf.get(), len)!=len) {
return false;
}
text.assign(sp_buf.get(), len);
return true;
}
class fork_socketpair_info : public fork_pipe_info {};
static bool fork_socketpair_child_process(fork_socketpair_info & finfo) {
int fd[2];
if (socketpair(PF_UNIX, SOCK_DGRAM, 0, fd) < 0) {
return false;
}
pid_t pid;
if ((pid = fork()) < 0) {
//fork error
return false;
}
finfo.pid = pid;
if(pid == 0) { // child process
close(fd[0]); //close read pipe
finfo.fd_read = -1;
finfo.fd_write = fd[1];
return true;
}
// father process
close(fd[1]); //close write pipe
finfo.fd_read = fd[0];
finfo.fd_write = -1;
return false;
}
static bool write_fd_to_father(const fork_socketpair_info & finfo, int fd) {
iovec iov[1];
msghdr msg;
char buff[0];
//指定缓冲区
iov[0].iov_base = buff;
iov[0].iov_len = 1;
//通过socketpair进行通信，不需要知道ip地址
msg.msg_name = nullptr;
msg.msg_namelen = 0;
//指定内存缓冲区
msg.msg_iov = iov;
msg.msg_iovlen = 1;
//辅助数据
cmsghdr cm;
cm.cmsg_len = CMSG_LEN(sizeof(fd)); //描述符的大小
cm.cmsg_level = SOL_SOCKET; //表示传递的辅助数据是文件描述符
cm.cmsg_type = SCM_RIGHTS; //协议类型
*(int*)CMSG_DATA(&cm) = fd; //设置待发送描述符
//设置辅助数据
msg.msg_control = &cm;
msg.msg_controllen = CMSG_LEN(sizeof(fd));
if(sendmsg(finfo.fd_write, &msg, 0) == -1) {
return false;
}
return true;
}
static bool read_fd_from_child(const fork_socketpair_info & finfo, int & fd) {
iovec iov[1];
msghdr msg;
char buff[0];
//指定缓冲区
iov[0].iov_base = buff;
iov[0].iov_len = 1;
//通过socketpair进行通信，不需要知道ip地址
msg.msg_name = nullptr;
msg.msg_namelen = 0;
//指定内存缓冲区
msg.msg_iov = iov;
msg.msg_iovlen = 1;
//辅助数据
cmsghdr cm;
//设置辅助数据
msg.msg_control = &cm;
msg.msg_controllen = CMSG_LEN(sizeof(fd));
if(recvmsg(finfo.fd_read, &msg, 0) == -1) {
return false;
}
fd = *(int*)CMSG_DATA(&cm);
return true;
}
#endif /* _SAFE_FORK_HELPER_H_ */