forked from MarcoBuster/Magisk
153 lines
3.7 KiB
C
153 lines
3.7 KiB
C
/* socket.c - All socket related operations
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*/
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#include <fcntl.h>
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#include "daemon.h"
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#include "logging.h"
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#include "utils.h"
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#include "magisk.h"
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/* Setup the address and return socket fd */
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int setup_socket(struct sockaddr_un *sun) {
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int fd = xsocket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
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memset(sun, 0, sizeof(*sun));
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sun->sun_family = AF_LOCAL;
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memcpy(sun->sun_path, REQUESTOR_DAEMON_PATH, sizeof(REQUESTOR_DAEMON_PATH) - 1);
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return fd;
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}
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/*
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* Receive a file descriptor from a Unix socket.
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* Contributed by @mkasick
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*
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* Returns the file descriptor on success, or -1 if a file
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* descriptor was not actually included in the message
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*
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* On error the function terminates by calling exit(-1)
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*/
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int recv_fd(int sockfd) {
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// Need to receive data from the message, otherwise don't care about it.
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char iovbuf;
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struct iovec iov = {
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.iov_base = &iovbuf,
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.iov_len = 1,
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};
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char cmsgbuf[CMSG_SPACE(sizeof(int))];
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struct msghdr msg = {
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.msg_iov = &iov,
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.msg_iovlen = 1,
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.msg_control = cmsgbuf,
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.msg_controllen = sizeof(cmsgbuf),
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};
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xrecvmsg(sockfd, &msg, MSG_WAITALL);
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// Was a control message actually sent?
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switch (msg.msg_controllen) {
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case 0:
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// No, so the file descriptor was closed and won't be used.
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return -1;
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case sizeof(cmsgbuf):
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// Yes, grab the file descriptor from it.
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break;
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default:
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goto error;
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}
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struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
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if (cmsg == NULL ||
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cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
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cmsg->cmsg_level != SOL_SOCKET ||
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cmsg->cmsg_type != SCM_RIGHTS) {
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error:
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LOGE("unable to read fd");
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exit(-1);
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}
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return *(int *)CMSG_DATA(cmsg);
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}
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/*
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* Send a file descriptor through a Unix socket.
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* Contributed by @mkasick
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*
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* On error the function terminates by calling exit(-1)
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*
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* fd may be -1, in which case the dummy data is sent,
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* but no control message with the FD is sent.
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*/
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void send_fd(int sockfd, int fd) {
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// Need to send some data in the message, this will do.
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struct iovec iov = {
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.iov_base = "",
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.iov_len = 1,
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};
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struct msghdr msg = {
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.msg_iov = &iov,
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.msg_iovlen = 1,
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};
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char cmsgbuf[CMSG_SPACE(sizeof(int))];
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if (fd != -1) {
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// Is the file descriptor actually open?
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if (fcntl(fd, F_GETFD) == -1) {
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if (errno != EBADF) {
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PLOGE("unable to send fd");
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}
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// It's closed, don't send a control message or sendmsg will EBADF.
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} else {
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// It's open, send the file descriptor in a control message.
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msg.msg_control = cmsgbuf;
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msg.msg_controllen = sizeof(cmsgbuf);
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struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
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cmsg->cmsg_len = CMSG_LEN(sizeof(int));
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cmsg->cmsg_level = SOL_SOCKET;
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cmsg->cmsg_type = SCM_RIGHTS;
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*(int *)CMSG_DATA(cmsg) = fd;
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}
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}
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xsendmsg(sockfd, &msg, 0);
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}
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int read_int(int fd) {
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int val;
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xxread(fd, &val, sizeof(int));
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return val;
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}
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void write_int(int fd, int val) {
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if (fd < 0) return;
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xwrite(fd, &val, sizeof(int));
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}
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char* read_string(int fd) {
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int len = read_int(fd);
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if (len > PATH_MAX || len < 0) {
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LOGE("invalid string length %d", len);
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exit(1);
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}
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char* val = xmalloc(sizeof(char) * (len + 1));
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xxread(fd, val, len);
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val[len] = '\0';
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return val;
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}
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void write_string(int fd, const char* val) {
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if (fd < 0) return;
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int len = strlen(val);
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write_int(fd, len);
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xwrite(fd, val, len);
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}
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