From 3ee897d6c2401effbc82f5eef35fce405781d6c8 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 23 Sep 2015 01:00:04 +0200 Subject: tree-wide: port more code to use send_one_fd() and receive_one_fd() Also, make it slightly more powerful, by accepting a flags argument, and make it safe for handling if more than one cmsg attribute happens to be attached. --- src/basic/util.c | 84 ++++++++++++++++---------------------------------------- 1 file changed, 24 insertions(+), 60 deletions(-) (limited to 'src/basic/util.c') diff --git a/src/basic/util.c b/src/basic/util.c index bc61ec0115..c788a1d58b 100644 --- a/src/basic/util.c +++ b/src/basic/util.c @@ -6201,15 +6201,6 @@ int ptsname_malloc(int fd, char **ret) { int openpt_in_namespace(pid_t pid, int flags) { _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1; _cleanup_close_pair_ int pair[2] = { -1, -1 }; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int))]; - } control = {}; - struct msghdr mh = { - .msg_control = &control, - .msg_controllen = sizeof(control), - }; - struct cmsghdr *cmsg; siginfo_t si; pid_t child; int r; @@ -6243,15 +6234,7 @@ int openpt_in_namespace(pid_t pid, int flags) { if (unlockpt(master) < 0) _exit(EXIT_FAILURE); - cmsg = CMSG_FIRSTHDR(&mh); - cmsg->cmsg_level = SOL_SOCKET; - cmsg->cmsg_type = SCM_RIGHTS; - cmsg->cmsg_len = CMSG_LEN(sizeof(int)); - memcpy(CMSG_DATA(cmsg), &master, sizeof(int)); - - mh.msg_controllen = cmsg->cmsg_len; - - if (sendmsg(pair[1], &mh, MSG_NOSIGNAL) < 0) + if (send_one_fd(pair[1], master, 0) < 0) _exit(EXIT_FAILURE); _exit(EXIT_SUCCESS); @@ -6265,26 +6248,7 @@ int openpt_in_namespace(pid_t pid, int flags) { if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS) return -EIO; - if (recvmsg(pair[0], &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) < 0) - return -errno; - - CMSG_FOREACH(cmsg, &mh) - if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { - int *fds; - unsigned n_fds; - - fds = (int*) CMSG_DATA(cmsg); - n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); - - if (n_fds != 1) { - close_many(fds, n_fds); - return -EIO; - } - - return fds[0]; - } - - return -EIO; + return receive_one_fd(pair[0], 0); } ssize_t fgetxattrat_fake(int dirfd, const char *filename, const char *attribute, void *value, size_t size, int flags) { @@ -6884,7 +6848,7 @@ int fgetxattr_malloc(int fd, const char *name, char **value) { } } -int send_one_fd(int transport_fd, int fd) { +int send_one_fd(int transport_fd, int fd, int flags) { union { struct cmsghdr cmsghdr; uint8_t buf[CMSG_SPACE(sizeof(int))]; @@ -6894,7 +6858,6 @@ int send_one_fd(int transport_fd, int fd) { .msg_controllen = sizeof(control), }; struct cmsghdr *cmsg; - ssize_t k; assert(transport_fd >= 0); assert(fd >= 0); @@ -6906,14 +6869,13 @@ int send_one_fd(int transport_fd, int fd) { memcpy(CMSG_DATA(cmsg), &fd, sizeof(int)); mh.msg_controllen = CMSG_SPACE(sizeof(int)); - k = sendmsg(transport_fd, &mh, MSG_NOSIGNAL); - if (k < 0) + if (sendmsg(transport_fd, &mh, MSG_NOSIGNAL | flags) < 0) return -errno; return 0; } -int receive_one_fd(int transport_fd) { +int receive_one_fd(int transport_fd, int flags) { union { struct cmsghdr cmsghdr; uint8_t buf[CMSG_SPACE(sizeof(int))]; @@ -6922,33 +6884,35 @@ int receive_one_fd(int transport_fd) { .msg_control = &control, .msg_controllen = sizeof(control), }; - struct cmsghdr *cmsg; - ssize_t k; + struct cmsghdr *cmsg, *found = NULL; assert(transport_fd >= 0); /* - * Receive a single FD via @transport_fd. We don't care for the - * transport-type, but the caller must assure that no other CMSG types - * than SCM_RIGHTS is enabled. We also retrieve a single FD at most, so - * for packet-based transports, the caller must ensure to send only a - * single FD per packet. - * This is best used in combination with send_one_fd(). + * Receive a single FD via @transport_fd. We don't care for + * the transport-type. We retrieve a single FD at most, so for + * packet-based transports, the caller must ensure to send + * only a single FD per packet. This is best used in + * combination with send_one_fd(). */ - k = recvmsg(transport_fd, &mh, MSG_NOSIGNAL | MSG_CMSG_CLOEXEC); - if (k < 0) + if (recvmsg(transport_fd, &mh, MSG_NOSIGNAL | MSG_CMSG_CLOEXEC | flags) < 0) return -errno; - cmsg = CMSG_FIRSTHDR(&mh); - if (!cmsg || CMSG_NXTHDR(&mh, cmsg) || - cmsg->cmsg_level != SOL_SOCKET || - cmsg->cmsg_type != SCM_RIGHTS || - cmsg->cmsg_len != CMSG_LEN(sizeof(int)) || - *(const int *)CMSG_DATA(cmsg) < 0) { + CMSG_FOREACH(cmsg, &mh) { + if (cmsg->cmsg_level == SOL_SOCKET && + cmsg->cmsg_type == SCM_RIGHTS && + cmsg->cmsg_len == CMSG_LEN(sizeof(int))) { + assert(!found); + found = cmsg; + break; + } + } + + if (!found) { cmsg_close_all(&mh); return -EIO; } - return *(const int *)CMSG_DATA(cmsg); + return *(int*) CMSG_DATA(found); } -- cgit v1.2.3-54-g00ecf