From 264df02658ee7bca1ff7b1391f4b2494846f9c1a Mon Sep 17 00:00:00 2001 From: "C. McEnroe" Date: Fri, 13 Nov 2020 01:47:20 -0500 Subject: Use a fixed size pollfd array in calico My thinking here is that it's better to not allocate in response to incoming connections. This also just makes the code a little simpler. --- dispatch.c | 130 +++++++++++++++++++++++++++---------------------------------- 1 file changed, 57 insertions(+), 73 deletions(-) (limited to 'dispatch.c') diff --git a/dispatch.c b/dispatch.c index f4cda87..2b85857 100644 --- a/dispatch.c +++ b/dispatch.c @@ -25,6 +25,7 @@ * covered work. */ +#include #include #include #include @@ -44,49 +45,6 @@ #include #endif -static struct { - struct pollfd *ptr; - size_t len, cap; -} event; - -static void eventAdd(int fd) { - if (event.len == event.cap) { - event.cap = (event.cap ? event.cap * 2 : 8); - event.ptr = realloc(event.ptr, sizeof(*event.ptr) * event.cap); - if (!event.ptr) err(EX_OSERR, "malloc"); - } - event.ptr[event.len++] = (struct pollfd) { - .fd = fd, - .events = POLLIN, - }; -} - -static void eventRemove(size_t i) { - close(event.ptr[i].fd); - event.ptr[i] = event.ptr[--event.len]; -} - -static ssize_t sendfd(int sock, int fd) { - char buf[CMSG_SPACE(sizeof(int))]; - - char x = 0; - struct iovec iov = { .iov_base = &x, .iov_len = 1 }; - struct msghdr msg = { - .msg_iov = &iov, - .msg_iovlen = 1, - .msg_control = buf, - .msg_controllen = sizeof(buf), - }; - - struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg); - cmsg->cmsg_len = CMSG_LEN(sizeof(int)); - cmsg->cmsg_level = SOL_SOCKET; - cmsg->cmsg_type = SCM_RIGHTS; - *(int *)CMSG_DATA(cmsg) = fd; - - return sendmsg(sock, &msg, 0); -} - static struct { uint8_t buf[4096]; uint8_t *ptr; @@ -156,6 +114,27 @@ static void alert(int sock) { if (len < 0) warn("send"); } +static ssize_t sendfd(int sock, int fd) { + char buf[CMSG_SPACE(sizeof(int))]; + + char x = 0; + struct iovec iov = { .iov_base = &x, .iov_len = 1 }; + struct msghdr msg = { + .msg_iov = &iov, + .msg_iovlen = 1, + .msg_control = buf, + .msg_controllen = sizeof(buf), + }; + + struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg); + cmsg->cmsg_len = CMSG_LEN(sizeof(int)); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + *(int *)CMSG_DATA(cmsg) = fd; + + return sendmsg(sock, &msg, 0); +} + int main(int argc, char *argv[]) { int error; @@ -196,6 +175,10 @@ int main(int argc, char *argv[]) { error = fchdir(dir); if (error) err(EX_NOINPUT, "%s", path); + enum { Cap = 1024 }; + struct pollfd fds[Cap]; + size_t nfds = 0; + struct addrinfo *head; struct addrinfo hints = { .ai_family = AF_UNSPEC, @@ -206,7 +189,7 @@ int main(int argc, char *argv[]) { if (error) errx(EX_NOHOST, "%s:%s: %s", host, port, gai_strerror(error)); size_t binds = 0; - for (struct addrinfo *ai = head; ai; ai = ai->ai_next) { + for (struct addrinfo *ai = head; ai && binds < Cap - 1; ai = ai->ai_next) { int sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); if (sock < 0) err(EX_OSERR, "socket"); @@ -223,7 +206,7 @@ int main(int argc, char *argv[]) { continue; } - eventAdd(sock); + fds[nfds++] = (struct pollfd) { .fd = sock, .events = POLLIN }; binds++; } if (!binds) errx(EX_UNAVAILABLE, "could not bind any sockets"); @@ -243,63 +226,62 @@ int main(int argc, char *argv[]) { error = cap_rights_limit(dir, &dirRights); if (error) err(EX_OSERR, "cap_rights_limit"); for (size_t i = 0; i < binds; ++i) { - error = cap_rights_limit(event.ptr[i].fd, &bindRights); + error = cap_rights_limit(fds[i].fd, &bindRights); if (error) err(EX_OSERR, "cap_rights_limit"); } #endif for (size_t i = 0; i < binds; ++i) { - error = listen(event.ptr[i].fd, -1); + error = listen(fds[i].fd, -1); if (error) err(EX_IOERR, "listen"); } signal(SIGPIPE, SIG_IGN); for (;;) { - int nfds = poll( - event.ptr, event.len, (event.len > binds ? timeout : -1) - ); - if (nfds < 0) err(EX_IOERR, "poll"); + for (size_t i = 0; i < binds; ++i) { + fds[i].events = (nfds < Cap ? POLLIN : 0); + } - if (!nfds) { - for (size_t i = event.len - 1; i >= binds; --i) { - eventRemove(i); + int ready = poll(fds, nfds, (nfds > binds ? timeout : -1)); + if (ready < 0) err(EX_IOERR, "poll"); + + if (!ready) { + for (size_t i = binds; i < nfds; ++i) { + close(fds[i].fd); } + nfds = binds; continue; } - for (size_t i = event.len - 1; i < event.len; --i) { - if (!event.ptr[i].revents) continue; + for (size_t i = nfds - 1; i < nfds; --i) { + if (!fds[i].revents) continue; if (i < binds) { - int sock = accept(event.ptr[i].fd, NULL, NULL); + int sock = accept(fds[i].fd, NULL, NULL); if (sock < 0) { warn("accept"); continue; } - eventAdd(sock); + assert(nfds < Cap); + fds[nfds++] = (struct pollfd) { .fd = sock, .events = POLLIN }; continue; } - if (event.ptr[i].revents & (POLLHUP | POLLERR)) { - eventRemove(i); - continue; - } + if (fds[i].revents & (POLLHUP | POLLERR)) goto remove; ssize_t len = recv( - event.ptr[i].fd, peek.buf, sizeof(peek.buf) - 1, MSG_PEEK + fds[i].fd, peek.buf, sizeof(peek.buf) - 1, MSG_PEEK ); if (len < 0) { warn("recv"); - eventRemove(i); - continue; + goto remove; } peek.len = len; char *name = serverName(); if (!name || name[0] == '.' || strchr(name, '/')) { - alert(event.ptr[i].fd); - eventRemove(i); - continue; + alert(fds[i].fd); + goto remove; } struct sockaddr_un addr = { .sun_family = AF_UNIX }; @@ -321,17 +303,19 @@ int main(int argc, char *argv[]) { if (error) { warn("%s", name); - alert(event.ptr[i].fd); + alert(fds[i].fd); } else { - len = sendfd(sock, event.ptr[i].fd); + len = sendfd(sock, fds[i].fd); if (len < 0) { warn("%s", name); - alert(event.ptr[i].fd); + alert(fds[i].fd); } } - close(sock); - eventRemove(i); + +remove: + close(fds[i].fd); + fds[i] = fds[--nfds]; } } } -- cgit 1.4.1