From 1cde387c8335360900b1955a9c69a620976b5d9a Mon Sep 17 00:00:00 2001 From: Edward Tomasz Napierala Date: Tue, 27 Feb 2018 10:54:15 +0000 Subject: [PATCH] Improve missing tty handling in init(8). This removes a check that did nothing - it was checking for ENXIO, which, with devfs, is no longer returned - and was badly placed anyway, and replaces it with similar one that works, and is done just before starting getty, instead of being done when rereading ttys(5). From the practical point of view, this makes init(8) handle disappearing terminals (eg /dev/ttyU*) gracefully, without unneccessary getty restarts and resulting error messages. Reviewed by: imp@ MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D14307 --- include/ttyent.h | 2 ++ lib/libc/gen/getttyent.3 | 6 +++++ lib/libc/gen/getttyent.c | 15 +++++++----- sbin/init/init.c | 50 +++++++++++++++++++++++++++++----------- 4 files changed, 53 insertions(+), 20 deletions(-) diff --git a/include/ttyent.h b/include/ttyent.h index cbefc87c62ca..a98fbdffb86f 100644 --- a/include/ttyent.h +++ b/include/ttyent.h @@ -57,6 +57,8 @@ struct ttyent { #define TTY_SECURE 0x02 /* allow uid of 0 to login */ #define TTY_DIALUP 0x04 /* is a dialup tty */ #define TTY_NETWORK 0x08 /* is a network tty */ +#define TTY_IFEXISTS 0x10 /* configured as "onifexists" */ +#define TTY_IFCONSOLE 0x20 /* configured as "onifconsole" */ int ty_status; /* status flags */ char *ty_window; /* command to start up window manager */ char *ty_comment; /* comment field */ diff --git a/lib/libc/gen/getttyent.3 b/lib/libc/gen/getttyent.3 index 1b1590d8ae59..a5e9156c7e61 100644 --- a/lib/libc/gen/getttyent.3 +++ b/lib/libc/gen/getttyent.3 @@ -75,6 +75,8 @@ struct ttyent { #define TTY_SECURE 0x02 /* allow uid of 0 to login */ #define TTY_DIALUP 0x04 /* is a dialup tty */ #define TTY_NETWORK 0x08 /* is a network tty */ +#define TTY_IFEXISTS 0x10 /* configured as "onifexists" */ +#define TTY_IFCONSOLE 0x20 /* configured as "onifconsole" */ int ty_status; /* status flags */ char *ty_window; /* command to start up window manager */ char *ty_comment; /* comment field */ @@ -115,6 +117,10 @@ Identifies a tty used for network connections. If this flag is set, then .Fn isnettty will return a non-zero value. +.It Dv TTY_IFEXISTS +Identifies a tty that does not neccessarily exist. +.It Dv TTY_IFCONSOLE +Identifies a tty that might be a system console. .El .It Fa ty_window The command to execute for a window system associated with the line. diff --git a/lib/libc/gen/getttyent.c b/lib/libc/gen/getttyent.c index 633a5f212372..cc36201a2d20 100644 --- a/lib/libc/gen/getttyent.c +++ b/lib/libc/gen/getttyent.c @@ -75,11 +75,14 @@ auto_tty_status(const char *ty_name) { size_t len; char *buf, *cons, *nextcons; + int rv; + + rv = TTY_IFCONSOLE; /* Check if this is an enabled kernel console line */ buf = NULL; if (sysctlbyname("kern.console", NULL, &len, NULL, 0) == -1) - return (0); /* Errors mean don't enable */ + return (rv); /* Errors mean don't enable */ buf = malloc(len); if (sysctlbyname("kern.console", buf, &len, NULL, 0) == -1) goto done; @@ -90,14 +93,14 @@ auto_tty_status(const char *ty_name) nextcons = buf; while ((cons = strsep(&nextcons, ",")) != NULL && strlen(cons) != 0) { if (strcmp(cons, ty_name) == 0) { - free(buf); - return (TTY_ON); + rv |= TTY_ON; + break; } } done: free(buf); - return (0); + return (rv); } static int @@ -107,13 +110,13 @@ auto_exists_status(const char *ty_name) char *dev; int rv; - rv = 0; + rv = TTY_IFEXISTS; if (*ty_name == '/') asprintf(&dev, "%s", ty_name); else asprintf(&dev, "/dev/%s", ty_name); if (dev != NULL && stat(dev, &sb) == 0) - rv = TTY_ON; + rv |= TTY_ON; free(dev); return (rv); } diff --git a/sbin/init/init.c b/sbin/init/init.c index e0ec7cd891ea..235c3f13ffd3 100644 --- a/sbin/init/init.c +++ b/sbin/init/init.c @@ -156,6 +156,8 @@ typedef struct init_session { int se_flags; /* status of session */ #define SE_SHUTDOWN 0x1 /* session won't be restarted */ #define SE_PRESENT 0x2 /* session is in /etc/ttys */ +#define SE_IFEXISTS 0x4 /* session defined as "onifexists" */ +#define SE_IFCONSOLE 0x8 /* session defined as "onifconsole" */ int se_nspace; /* spacing count */ char *se_device; /* filename of port */ char *se_getty; /* what to run on that port */ @@ -1262,7 +1264,6 @@ static session_t * new_session(session_t *sprev, struct ttyent *typ) { session_t *sp; - int fd; if ((typ->ty_status & TTY_ON) == 0 || typ->ty_name == 0 || @@ -1273,21 +1274,15 @@ new_session(session_t *sprev, struct ttyent *typ) sp->se_flags |= SE_PRESENT; + if ((typ->ty_status & TTY_IFEXISTS) != 0) + sp->se_flags |= SE_IFEXISTS; + + if ((typ->ty_status & TTY_IFCONSOLE) != 0) + sp->se_flags |= SE_IFCONSOLE; + if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) < 0) err(1, "asprintf"); - /* - * Attempt to open the device, if we get "device not configured" - * then don't add the device to the session list. - */ - if ((fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0)) < 0) { - if (errno == ENXIO) { - free_session(sp); - return (0); - } - } else - close(fd); - if (setupargv(sp, typ) == 0) { free_session(sp); return (0); @@ -1506,6 +1501,30 @@ start_getty(session_t *sp) _exit(1); } +/* + * Return 1 if the session is defined as "onifexists" + * or "onifconsole" and the device node does not exist. + */ +static int +session_has_no_tty(session_t *sp) +{ + int fd; + + if ((sp->se_flags & SE_IFEXISTS) == 0 && + (sp->se_flags & SE_IFCONSOLE) == 0) + return (0); + + fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0); + if (fd < 0) { + if (errno == ENOENT) + return (1); + return (0); + } + + close(fd); + return (0); +} + /* * Collect exit status for a child. * If an exiting login, start a new login running. @@ -1524,7 +1543,8 @@ collect_child(pid_t pid) del_session(sp); sp->se_process = 0; - if (sp->se_flags & SE_SHUTDOWN) { + if (sp->se_flags & SE_SHUTDOWN || + session_has_no_tty(sp)) { if ((sprev = sp->se_prev) != NULL) sprev->se_next = sp->se_next; else @@ -1611,6 +1631,8 @@ multi_user(void) for (sp = sessions; sp; sp = sp->se_next) { if (sp->se_process) continue; + if (session_has_no_tty(sp)) + continue; if ((pid = start_getty(sp)) == -1) { /* serious trouble */ requested_transition = clean_ttys;