Date: Mon, 22 Apr 2019 13:57:53 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r346550 - head/usr.sbin/bhyve Message-ID: <201904221357.x3MDvreI024911@repo.freebsd.org>
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Author: markj Date: Mon Apr 22 13:57:52 2019 New Revision: 346550 URL: https://svnweb.freebsd.org/changeset/base/346550 Log: Use separate descriptors in bhyve's stdio uart backend. bhyve was previously using stdin for both reading and writing to the console, which made it difficult to redirect console output. Use stdin for reading and stdout for writing. This makes it easier to use bhyve as a backend for syzkaller. As a side effect, the change fixes a minor bug which would cause bhyve to fail with ENOTCAPABLE if configured to use nmdm for com1 and stdio for com2. bhyveload already uses separate descriptors, as does the bvmcons driver. Reviewed by: jhb MFC after: 1 month Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D19788 Modified: head/usr.sbin/bhyve/uart_emul.c Modified: head/usr.sbin/bhyve/uart_emul.c ============================================================================== --- head/usr.sbin/bhyve/uart_emul.c Mon Apr 22 13:55:06 2019 (r346549) +++ head/usr.sbin/bhyve/uart_emul.c Mon Apr 22 13:57:52 2019 (r346550) @@ -100,8 +100,8 @@ struct fifo { struct ttyfd { bool opened; - int fd; /* tty device file descriptor */ - struct termios tio_orig, tio_new; /* I/O Terminals */ + int rfd; /* fd for reading */ + int wfd; /* fd for writing, may be == rfd */ }; struct uart_softc { @@ -141,16 +141,15 @@ ttyclose(void) static void ttyopen(struct ttyfd *tf) { + struct termios orig, new; - tcgetattr(tf->fd, &tf->tio_orig); - - tf->tio_new = tf->tio_orig; - cfmakeraw(&tf->tio_new); - tf->tio_new.c_cflag |= CLOCAL; - tcsetattr(tf->fd, TCSANOW, &tf->tio_new); - - if (tf->fd == STDIN_FILENO) { - tio_stdio_orig = tf->tio_orig; + tcgetattr(tf->rfd, &orig); + new = orig; + cfmakeraw(&new); + new.c_cflag |= CLOCAL; + tcsetattr(tf->rfd, TCSANOW, &new); + if (uart_stdio) { + tio_stdio_orig = orig; atexit(ttyclose); } } @@ -160,7 +159,7 @@ ttyread(struct ttyfd *tf) { unsigned char rb; - if (read(tf->fd, &rb, 1) == 1) + if (read(tf->rfd, &rb, 1) == 1) return (rb); else return (-1); @@ -170,7 +169,7 @@ static void ttywrite(struct ttyfd *tf, unsigned char wb) { - (void)write(tf->fd, &wb, 1); + (void)write(tf->wfd, &wb, 1); } static void @@ -190,7 +189,7 @@ rxfifo_reset(struct uart_softc *sc, int size) * Flush any unread input from the tty buffer. */ while (1) { - nread = read(sc->tty.fd, flushbuf, sizeof(flushbuf)); + nread = read(sc->tty.rfd, flushbuf, sizeof(flushbuf)); if (nread != sizeof(flushbuf)) break; } @@ -277,7 +276,7 @@ uart_opentty(struct uart_softc *sc) { ttyopen(&sc->tty); - sc->mev = mevent_add(sc->tty.fd, EVF_READ, uart_drain, sc); + sc->mev = mevent_add(sc->tty.rfd, EVF_READ, uart_drain, sc); assert(sc->mev != NULL); } @@ -374,7 +373,7 @@ uart_drain(int fd, enum ev_type ev, void *arg) sc = arg; - assert(fd == sc->tty.fd); + assert(fd == sc->tty.rfd); assert(ev == EVF_READ); /* @@ -637,68 +636,79 @@ uart_init(uart_intr_func_t intr_assert, uart_intr_func } static int -uart_tty_backend(struct uart_softc *sc, const char *opts) +uart_stdio_backend(struct uart_softc *sc) { - int fd; - int retval; +#ifndef WITHOUT_CAPSICUM + cap_rights_t rights; + cap_ioctl_t cmds[] = { TIOCGETA, TIOCSETA, TIOCGWINSZ }; +#endif - retval = -1; + if (uart_stdio) + return (-1); - fd = open(opts, O_RDWR | O_NONBLOCK); - if (fd > 0 && isatty(fd)) { - sc->tty.fd = fd; - sc->tty.opened = true; - retval = 0; - } + sc->tty.rfd = STDIN_FILENO; + sc->tty.wfd = STDOUT_FILENO; + sc->tty.opened = true; - return (retval); + if (fcntl(sc->tty.rfd, F_SETFL, O_NONBLOCK) != 0) + return (-1); + if (fcntl(sc->tty.wfd, F_SETFL, O_NONBLOCK) != 0) + return (-1); + +#ifndef WITHOUT_CAPSICUM + cap_rights_init(&rights, CAP_EVENT, CAP_IOCTL, CAP_READ); + if (caph_rights_limit(sc->tty.rfd, &rights) == -1) + errx(EX_OSERR, "Unable to apply rights for sandbox"); + if (caph_ioctls_limit(sc->tty.rfd, cmds, nitems(cmds)) == -1) + errx(EX_OSERR, "Unable to apply rights for sandbox"); +#endif + + uart_stdio = true; + + return (0); } -int -uart_set_backend(struct uart_softc *sc, const char *opts) +static int +uart_tty_backend(struct uart_softc *sc, const char *opts) { - int retval; #ifndef WITHOUT_CAPSICUM cap_rights_t rights; cap_ioctl_t cmds[] = { TIOCGETA, TIOCSETA, TIOCGWINSZ }; #endif + int fd; - retval = -1; + fd = open(opts, O_RDWR | O_NONBLOCK); + if (fd < 0 || !isatty(fd)) + return (-1); + sc->tty.rfd = sc->tty.wfd = fd; + sc->tty.opened = true; + +#ifndef WITHOUT_CAPSICUM + cap_rights_init(&rights, CAP_EVENT, CAP_IOCTL, CAP_READ, CAP_WRITE); + if (caph_rights_limit(fd, &rights) == -1) + errx(EX_OSERR, "Unable to apply rights for sandbox"); + if (caph_ioctls_limit(fd, cmds, nitems(cmds)) == -1) + errx(EX_OSERR, "Unable to apply rights for sandbox"); +#endif + + return (0); +} + +int +uart_set_backend(struct uart_softc *sc, const char *opts) +{ + int retval; + if (opts == NULL) return (0); - if (strcmp("stdio", opts) == 0) { - if (!uart_stdio) { - sc->tty.fd = STDIN_FILENO; - sc->tty.opened = true; - uart_stdio = true; - retval = 0; - } - } else if (uart_tty_backend(sc, opts) == 0) { - retval = 0; - } - - /* Make the backend file descriptor non-blocking */ + if (strcmp("stdio", opts) == 0) + retval = uart_stdio_backend(sc); + else + retval = uart_tty_backend(sc, opts); if (retval == 0) - retval = fcntl(sc->tty.fd, F_SETFL, O_NONBLOCK); - - if (retval == 0) { -#ifndef WITHOUT_CAPSICUM - cap_rights_init(&rights, CAP_EVENT, CAP_IOCTL, CAP_READ, - CAP_WRITE); - if (caph_rights_limit(sc->tty.fd, &rights) == -1) - errx(EX_OSERR, "Unable to apply rights for sandbox"); - if (caph_ioctls_limit(sc->tty.fd, cmds, nitems(cmds)) == -1) - errx(EX_OSERR, "Unable to apply rights for sandbox"); - if (!uart_stdio) { - if (caph_limit_stdin() == -1) - errx(EX_OSERR, - "Unable to apply rights for sandbox"); - } -#endif uart_opentty(sc); - } return (retval); }
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