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Update recv/send fd function

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topjohnwu 2021-08-19 04:36:47 -07:00
parent 6f9c3c4ff3
commit ffe47300a1
2 changed files with 84 additions and 97 deletions
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195
native/jni/core/socket.cpp
View File

@ -20,122 +20,107 @@ socklen_t setup_sockaddr(sockaddr_un *sun, const char *name) {
return socket_len(sun);
}
int socket_accept(int sockfd, int timeout) {
struct pollfd pfd = {
.fd = sockfd,
.events = POLL_IN
void get_client_cred(int fd, ucred *cred) {
socklen_t len = sizeof(*cred);
getsockopt(fd, SOL_SOCKET, SO_PEERCRED, cred, &len);
}
static int send_fds(int sockfd, void *cmsgbuf, size_t bufsz, const int *fds, int cnt) {
iovec iov = {
.iov_base = &cnt,
.iov_len = sizeof(cnt),
};
return xpoll(&pfd, 1, timeout * 1000) <= 0 ? -1 : xaccept4(sockfd, nullptr, nullptr, SOCK_CLOEXEC);
}
void get_client_cred(int fd, struct ucred *cred) {
socklen_t ucred_length = sizeof(*cred);
getsockopt(fd, SOL_SOCKET, SO_PEERCRED, cred, &ucred_length);
}
/*
* Receive a file descriptor from a Unix socket.
* Contributed by @mkasick
*
* Returns the file descriptor on success, or -1 if a file
* descriptor was not actually included in the message
*
* On error the function terminates by calling exit(-1)
*/
int recv_fd(int sockfd) {
// Need to receive data from the message, otherwise don't care about it.
char iovbuf;
struct cmsghdr *cmsg;
struct iovec iov = {
.iov_base = &iovbuf,
.iov_len = 1,
};
char cmsgbuf[CMSG_SPACE(sizeof(int))];
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = cmsgbuf,
.msg_controllen = sizeof(cmsgbuf),
};
xrecvmsg(sockfd, &msg, MSG_WAITALL);
// Was a control message actually sent?
switch (msg.msg_controllen) {
case 0:
// No, so the file descriptor was closed and won't be used.
return -1;
case sizeof(cmsgbuf):
// Yes, grab the file descriptor from it.
break;
default:
goto error;
}
cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg == nullptr ||
cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
cmsg->cmsg_level != SOL_SOCKET ||
cmsg->cmsg_type != SCM_RIGHTS) {
error:
LOGE("unable to read fd\n");
exit(-1);
}
return *(int *)CMSG_DATA(cmsg);
}
/*
* Send a file descriptor through a Unix socket.
* Contributed by @mkasick
*
* On error the function terminates by calling exit(-1)
*
* fd may be -1, in which case the dummy data is sent,
* but no control message with the FD is sent.
*/
void send_fd(int sockfd, int fd) {
// Need to send some data in the message, this will do.
char junk[] = { '\0' };
struct iovec iov = {
.iov_base = junk,
.iov_len = 1,
};
struct msghdr msg = {
msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
};
char cmsgbuf[CMSG_SPACE(sizeof(int))];
if (fd != -1) {
// Is the file descriptor actually open?
if (fcntl(fd, F_GETFD) == -1) {
if (errno != EBADF) {
PLOGE("unable to send fd");
}
// It's closed, don't send a control message or sendmsg will EBADF.
} else {
// It's open, send the file descriptor in a control message.
if (cnt) {
msg.msg_control = cmsgbuf;
msg.msg_controllen = sizeof(cmsgbuf);
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
msg.msg_controllen = bufsz;
cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(int) * cnt);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
*(int *)CMSG_DATA(cmsg) = fd;
}
memcpy(CMSG_DATA(cmsg), fds, sizeof(int) * cnt);
}
xsendmsg(sockfd, &msg, 0);
return xsendmsg(sockfd, &msg, 0);
}
int send_fds(int sockfd, const int *fds, int cnt) {
if (cnt == 0) {
return send_fds(sockfd, nullptr, 0, nullptr, 0);
}
vector<char> cmsgbuf;
cmsgbuf.resize(CMSG_SPACE(sizeof(int) * cnt));
return send_fds(sockfd, cmsgbuf.data(), cmsgbuf.size(), fds, cnt);
}
int send_fd(int sockfd, int fd) {
if (fd < 0) {
return send_fds(sockfd, nullptr, 0, nullptr, 0);
}
char cmsgbuf[CMSG_SPACE(sizeof(int))];
return send_fds(sockfd, cmsgbuf, sizeof(cmsgbuf), &fd, 1);
}
static void *recv_fds(int sockfd, char *cmsgbuf, size_t bufsz, int cnt) {
iovec iov = {
.iov_base = &cnt,
.iov_len = sizeof(cnt),
};
msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = cmsgbuf,
.msg_controllen = bufsz
};
xrecvmsg(sockfd, &msg, MSG_WAITALL);
cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
if (msg.msg_controllen != bufsz ||
cmsg == nullptr ||
cmsg->cmsg_len != CMSG_LEN(sizeof(int) * cnt) ||
cmsg->cmsg_level != SOL_SOCKET ||
cmsg->cmsg_type != SCM_RIGHTS) {
return nullptr;
}
return CMSG_DATA(cmsg);
}
vector<int> recv_fds(int sockfd) {
// Peek fd count to allocate proper buffer
int cnt;
recv(sockfd, &cnt, sizeof(cnt), MSG_PEEK);
vector<char> cmsgbuf;
cmsgbuf.resize(CMSG_SPACE(sizeof(int) * cnt));
vector<int> results;
void *data = recv_fds(sockfd, cmsgbuf.data(), cmsgbuf.size(), cnt);
if (data == nullptr)
return results;
results.resize(cnt);
memcpy(results.data(), data, sizeof(int) * cnt);
return results;
}
int recv_fd(int sockfd) {
char cmsgbuf[CMSG_SPACE(sizeof(int))];
void *data = recv_fds(sockfd, cmsgbuf, sizeof(cmsgbuf), 1);
if (data == nullptr)
return -1;
int result;
memcpy(&result, data, sizeof(int));
return result;
}
int read_int(int fd) {

8
native/jni/include/socket.hpp
View File

@ -3,12 +3,14 @@
#include <sys/un.h>
#include <sys/socket.h>
#include <string_view>
#include <vector>
socklen_t setup_sockaddr(sockaddr_un *sun, const char *name);
int socket_accept(int sockfd, int timeout);
void get_client_cred(int fd, struct ucred *cred);
void get_client_cred(int fd, ucred *cred);
std::vector<int> recv_fds(int sockfd);
int recv_fd(int sockfd);
void send_fd(int sockfd, int fd);
int send_fds(int sockfd, const int *fds, int cnt);
int send_fd(int sockfd, int fd);
int read_int(int fd);
int read_int_be(int fd);
void write_int(int fd, int val);