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| author | Karel Zak | 2019-05-27 13:07:12 +0200 |
|---|---|---|
| committer | Karel Zak | 2019-05-27 13:07:12 +0200 |
| commit | 2c864ba8fcf50246920d09feaa2b02f3a3dfd52c (patch) | |
| tree | e03eda273424729ccd1820ef89fbaa71c79423f0 /term-utils/mesg.c | |
| parent | lib/ttyutils: introduce get_terminal_stdfd() (diff) | |
| download | kernel-qcow2-util-linux-2c864ba8fcf50246920d09feaa2b02f3a3dfd52c.tar.gz kernel-qcow2-util-linux-2c864ba8fcf50246920d09feaa2b02f3a3dfd52c.tar.xz kernel-qcow2-util-linux-2c864ba8fcf50246920d09feaa2b02f3a3dfd52c.zip | |
mesg: avoid 'ttyname failed: Success' message
The ttyname(3) can fail to access /dev/ path, and that will cause function
to fail without setting errno value with result of rather confusing error
message. Lets start setting stdin permission via /proc when this happens as
a go-around, with hope kernel following symlink does not fail. Ok, noted,
that hopes of symlink follow working are pretty slim.
Based on patch from Sami Kerola <kerolasa@iki.fi>.
Reference: https://github.com/lxc/lxd/issues/1724
Signed-off-by: Karel Zak <kzak@redhat.com>
Diffstat (limited to 'term-utils/mesg.c')
| -rw-r--r-- | term-utils/mesg.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/term-utils/mesg.c b/term-utils/mesg.c index 57d53379f..56fb70094 100644 --- a/term-utils/mesg.c +++ b/term-utils/mesg.c @@ -59,6 +59,8 @@ #include "nls.h" #include "c.h" #include "rpmatch.h" +#include "ttyutils.h" +#include "pathnames.h" /* exit codes */ @@ -90,6 +92,7 @@ int main(int argc, char *argv[]) { struct stat sb; char *tty; + char ttybuf[sizeof(_PATH_PROC_FDDIR) + sizeof(stringify_value(INT_MAX))]; int ch, fd, verbose = FALSE, ret; static const struct option longopts[] = { @@ -121,13 +124,21 @@ int main(int argc, char *argv[]) argc -= optind; argv += optind; - if (!isatty(STDERR_FILENO)) { + fd = get_terminal_stdfd(); + if (fd < 0) { if (verbose) warnx(_("no tty")); exit(MESG_EXIT_FAILURE); } - if ((tty = ttyname(STDERR_FILENO)) == NULL) - err(MESG_EXIT_FAILURE, _("ttyname failed")); + + tty = ttyname(fd); + if (!tty) { + snprintf(ttybuf, sizeof(ttybuf), "%s/%d", _PATH_PROC_FDDIR, fd); + tty = ttybuf; + if (verbose) + warnx(_("ttyname() failed, attempting to go around using: %s"), tty); + } + if ((fd = open(tty, O_RDONLY)) < 0) err(MESG_EXIT_FAILURE, _("cannot open %s"), tty); if (fstat(fd, &sb)) |