diff options
Diffstat (limited to 'src/nxt_socket_msg.h')
| -rw-r--r-- | src/nxt_socket_msg.h | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/src/nxt_socket_msg.h b/src/nxt_socket_msg.h new file mode 100644 index 00000000..04de1761 --- /dev/null +++ b/src/nxt_socket_msg.h @@ -0,0 +1,220 @@ +/* + * Copyright (C) NGINX, Inc. + */ + +#ifndef _NXT_SOCKET_MSG_H_INCLUDED_ +#define _NXT_SOCKET_MSG_H_INCLUDED_ + +#if (NXT_HAVE_UCRED) +#include <sys/un.h> +#endif + + +#if (NXT_HAVE_UCRED) +#define NXT_CRED_USECMSG 1 +#define NXT_CRED_CMSGTYPE SCM_CREDENTIALS +#define NXT_CRED_GETPID(u) (u->pid) + +typedef struct ucred nxt_socket_cred_t; + +#elif (NXT_HAVE_MSGHDR_CMSGCRED) +#define NXT_CRED_USECMSG 1 +#define NXT_CRED_CMSGTYPE SCM_CREDS +#define NXT_CRED_GETPID(u) (u->cmcred_pid) + +typedef struct cmsgcred nxt_socket_cred_t; +#endif + +#if (NXT_CRED_USECMSG) +#define NXT_OOB_RECV_SIZE \ + (CMSG_SPACE(2 * sizeof(int)) + CMSG_SPACE(sizeof(nxt_socket_cred_t))) +#else +#define NXT_OOB_RECV_SIZE \ + CMSG_SPACE(2 * sizeof(int)) +#endif + +#if (NXT_HAVE_MSGHDR_CMSGCRED) +#define NXT_OOB_SEND_SIZE \ + (CMSG_SPACE(2 * sizeof(int)) + CMSG_SPACE(sizeof(nxt_socket_cred_t))) +#else +#define NXT_OOB_SEND_SIZE \ + CMSG_SPACE(2 * sizeof(int)) +#endif + + +typedef struct { + size_t size; + u_char buf[NXT_OOB_RECV_SIZE]; +} nxt_recv_oob_t; + + +typedef struct { + size_t size; + u_char buf[NXT_OOB_SEND_SIZE]; +} nxt_send_oob_t; + + +/** + * The nxt_sendmsg is a wrapper for sendmsg. + * The oob struct must be initialized using nxt_socket_msg_oob_init(). + */ +NXT_EXPORT ssize_t nxt_sendmsg(nxt_socket_t s, nxt_iobuf_t *iob, + nxt_uint_t niob, const nxt_send_oob_t *oob); + +/** + * The nxt_recvmsg is a wrapper for recvmsg. + * The oob buffer must be consumed by using nxt_socket_msg_oob_get(). + */ +NXT_EXPORT ssize_t nxt_recvmsg(nxt_socket_t s, + nxt_iobuf_t *iob, nxt_uint_t niob, nxt_recv_oob_t *oob); + + +nxt_inline void +nxt_socket_msg_oob_init(nxt_send_oob_t *oob, int *fds) +{ + int nfds; + struct cmsghdr *cmsg; + +#if (NXT_HAVE_MSGHDR_CMSGCRED) + cmsg = (struct cmsghdr *) (oob->buf); + /* + * Fill all padding fields with 0. + * Code in Go 1.11 validate cmsghdr using padding field as part of len. + * See Cmsghdr definition and socketControlMessageHeaderAndData function. + */ + nxt_memzero(cmsg, sizeof(struct cmsghdr)); + + cmsg->cmsg_len = CMSG_LEN(sizeof(nxt_socket_cred_t)); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = NXT_CRED_CMSGTYPE; + + oob->size = CMSG_SPACE(sizeof(nxt_socket_cred_t)); + +#else + oob->size = 0; +#endif + + nfds = (fds[0] != -1 ? 1 : 0) + (fds[1] != -1 ? 1 : 0); + + if (nfds == 0) { + return; + } + + cmsg = (struct cmsghdr *) (oob->buf + oob->size); + + nxt_memzero(cmsg, sizeof(struct cmsghdr)); + + cmsg->cmsg_len = CMSG_LEN(nfds * sizeof(int)); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + + /* + * nxt_memcpy() is used instead of simple + * *(int *) CMSG_DATA(&cmsg.cm) = fd; + * because GCC 4.4 with -O2/3/s optimization may issue a warning: + * dereferencing type-punned pointer will break strict-aliasing rules + * + * Fortunately, GCC with -O1 compiles this nxt_memcpy() + * in the same simple assignment as in the code above. + */ + nxt_memcpy(CMSG_DATA(cmsg), fds, nfds * sizeof(int)); + + oob->size += CMSG_SPACE(nfds * sizeof(int)); +} + + +nxt_inline nxt_int_t +nxt_socket_msg_oob_get_fds(nxt_recv_oob_t *oob, nxt_fd_t *fd) +{ + size_t size; + struct msghdr msg; + struct cmsghdr *cmsg; + + msg.msg_control = oob->buf; + msg.msg_controllen = oob->size; + + for (cmsg = CMSG_FIRSTHDR(&msg); + cmsg != NULL; + cmsg = CMSG_NXTHDR(&msg, cmsg)) + { + size = cmsg->cmsg_len - CMSG_LEN(0); + + if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { + if (nxt_slow_path(size != sizeof(int) && size != 2 * sizeof(int))) { + return NXT_ERROR; + } + + nxt_memcpy(fd, CMSG_DATA(cmsg), size); + + return NXT_OK; + } + } + + return NXT_OK; +} + + +nxt_inline nxt_int_t +nxt_socket_msg_oob_get(nxt_recv_oob_t *oob, nxt_fd_t *fd, nxt_pid_t *pid) +{ + size_t size; + struct msghdr msg; + struct cmsghdr *cmsg; + + if (oob->size == 0) { + return NXT_OK; + } + +#if (NXT_CRED_USECMSG) + *pid = -1; +#endif + + msg.msg_control = oob->buf; + msg.msg_controllen = oob->size; + + for (cmsg = CMSG_FIRSTHDR(&msg); + cmsg != NULL; + cmsg = CMSG_NXTHDR(&msg, cmsg)) + { + size = cmsg->cmsg_len - CMSG_LEN(0); + + if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { + if (nxt_slow_path(size != sizeof(int) && size != 2 * sizeof(int))) { + return NXT_ERROR; + } + + nxt_memcpy(fd, CMSG_DATA(cmsg), size); + +#if (!NXT_CRED_USECMSG) + break; +#endif + } + +#if (NXT_CRED_USECMSG) + else if (cmsg->cmsg_level == SOL_SOCKET + && cmsg->cmsg_type == NXT_CRED_CMSGTYPE) + { + nxt_socket_cred_t *creds; + + if (nxt_slow_path(size != sizeof(nxt_socket_cred_t))) { + return NXT_ERROR; + } + + creds = (nxt_socket_cred_t *) CMSG_DATA(cmsg); + *pid = NXT_CRED_GETPID(creds); + } +#endif + } + +#if (NXT_CRED_USECMSG) + /* For platforms supporting credential passing, it's enforced */ + if (nxt_slow_path(*pid == -1)) { + return NXT_ERROR; + } +#endif + + return NXT_OK; +} + + +#endif /* _NXT_SOCKET_MSG_H_INCLUDED_ */ |