From c84971995b3a6d5118f9357c040572f4c78bcd55 Mon Sep 17 00:00:00 2001 From: Benjamin Peterson Date: Thu, 13 Sep 2018 14:23:42 -0700 Subject: [PATCH] improve error handling of ttyname_r and isatty POSIX allows ttyname(_r) and isatty to return EBADF if passed file descriptor is invalid. maintainer's note: these are optional ("may fail") errors, but it's non-conforming for ttyname_r to return ENOTTY when it failed for a different reason. --- src/unistd/isatty.c | 6 +++++- src/unistd/ttyname_r.c | 2 +- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/src/unistd/isatty.c b/src/unistd/isatty.c index c8badaf5..75a9c186 100644 --- a/src/unistd/isatty.c +++ b/src/unistd/isatty.c @@ -1,9 +1,13 @@ #include +#include #include #include "syscall.h" int isatty(int fd) { struct winsize wsz; - return !__syscall(SYS_ioctl, fd, TIOCGWINSZ, &wsz); + unsigned long r = syscall(SYS_ioctl, fd, TIOCGWINSZ, &wsz); + if (r == 0) return 1; + if (errno != EBADF) errno = ENOTTY; + return 0; } diff --git a/src/unistd/ttyname_r.c b/src/unistd/ttyname_r.c index cb364c29..82acb75e 100644 --- a/src/unistd/ttyname_r.c +++ b/src/unistd/ttyname_r.c @@ -9,7 +9,7 @@ int ttyname_r(int fd, char *name, size_t size) char procname[sizeof "/proc/self/fd/" + 3*sizeof(int) + 2]; ssize_t l; - if (!isatty(fd)) return ENOTTY; + if (!isatty(fd)) return errno; __procfdname(procname, fd); l = readlink(procname, name, size); -- 2.25.1