* bug#20555: Emacs 24.2 vs 24.4 on Solaris: M-x shell and "tty => not a tty"
2015-05-12 6:08 ` bug#20555: " Paul Eggert
2015-05-12 6:36 ` Glenn Morris
@ 2015-06-01 16:53 ` 白井彰
2015-06-07 18:11 ` Glenn Morris
2015-06-02 16:45 ` 白井彰
2015-06-11 23:48 ` Paul Eggert
3 siblings, 1 reply; 8+ messages in thread
From: 白井彰 @ 2015-06-01 16:53 UTC (permalink / raw)
To: 20555; +Cc: Akira Shirai
I wrote a small program my-emacs-24.5.c, and found that grantpt(fd)
returned -1 after fcntl(fd, F_SETFD, FD_CLOEXEC).
Without fcntl(fd, F_SETFD, FD_CLOEXEC), grantpt(fd) returns 0.
aaa% sh emacs-24.5/build-aux/config.guess
i386-pc-solaris2.10
aaa% ls my-emacs-24.5.c
my-emacs-24.5.c
aaa% make my-emacs-24.5 && ./my-emacs-24.5
cc -o my-emacs-24.5 my-emacs-24.5.c
call_fcntl_fd_cloexec: 1
fcntl_result: 0
fd: 3
grantpt_result: -1
errno: 13
grantpt: Permission denied
aaa% make my-emacs-24.5 && ./my-emacs-24.5 call_fcntl_fd_cloexec=0
`my-emacs-24.5' is up to date.
call_fcntl_fd_cloexec: 0
fd: 3
grantpt_result: 0
bbb% sh emacs-24.5/build-aux/config.guess
sparc-sun-solaris2.8
bbb% rm my-emacs-24.5
bbb% make my-emacs-24.5 && ./my-emacs-24.5
cc -o my-emacs-24.5 my-emacs-24.5.c
call_fcntl_fd_cloexec: 1
fcntl_result: 0
fd: 3
grantpt_result: -1
errno: 0
grantpt: Error 0
bbb% make my-emacs-24.5 && ./my-emacs-24.5 call_fcntl_fd_cloexec=0
`my-emacs-24.5' is up to date.
call_fcntl_fd_cloexec: 0
fd: 3
grantpt_result: 0
% cat -n my-emacs-24.5.c
1 /* 24.5 */
2
3 #include <errno.h>
4 #include <fcntl.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <sys/stat.h>
9 #include <sys/types.h>
10 #include <unistd.h>
11
12 int call_fcntl_fd_cloexec;
13
14 enum { PTY_NAME_SIZE = 24 };
15
16 int emacs_open(const char *file, int oflags, int mode) {
17 #define O_CLOEXEC 0
18 int fd;
19 oflags |= O_CLOEXEC;
20 while ((fd = open(file, oflags, mode)) < 0 && errno == EINTR) abort();
21 if (! O_CLOEXEC && 0 <= fd) {
22 fprintf(stderr, "call_fcntl_fd_cloexec: %d\n", call_fcntl_fd_cloexec);
23 if (call_fcntl_fd_cloexec) {
24 int fcntl_result = fcntl(fd, F_SETFD, FD_CLOEXEC);
25 fprintf(stderr, "fcntl_result: %d\n", fcntl_result);
26 }
27 }
28 return fd;
29 }
30
31 static int allocate_pty(char pty_name[PTY_NAME_SIZE]) {
32 int fd;
33 strcpy(pty_name, "/dev/ptmx");
34 fd = emacs_open(pty_name, O_RDWR | O_NONBLOCK, 0);
35 fprintf(stderr, "fd: %d\n", fd);
36 if (fd >= 0) {
37 int grantpt_result = grantpt(fd);
38 fprintf(stderr, "grantpt_result: %d\n", grantpt_result);
39 if (grantpt_result != 0) {
40 fprintf(stderr, "errno: %d\n", errno);
41 perror("grantpt");
42 }
43 }
44 return fd;
45 }
46
47 int main(int argc, char **argv) {
48 char pty_name[PTY_NAME_SIZE];
49 if (argc == 2) call_fcntl_fd_cloexec = 0;
50 else call_fcntl_fd_cloexec = 1;
51 allocate_pty(pty_name);
52 return 0;
53 }
^ permalink raw reply [flat|nested] 8+ messages in thread* bug#20555: Emacs 24.2 vs 24.4 on Solaris: M-x shell and "tty => not a tty"
2015-05-12 6:08 ` bug#20555: " Paul Eggert
2015-05-12 6:36 ` Glenn Morris
2015-06-01 16:53 ` 白井彰
@ 2015-06-02 16:45 ` 白井彰
2015-06-11 23:48 ` Paul Eggert
3 siblings, 0 replies; 8+ messages in thread
From: 白井彰 @ 2015-06-02 16:45 UTC (permalink / raw)
To: 20555; +Cc: Akira Shirai
Today I found the same problem on Ruby:
| grantpt() doesn't work with CLOEXEC on Solaris 10
| http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?revision=33519&view=revision
They say that Solaris grantpt() internally uses a setuid root program
/usr/lib/pt_chmod which receives an fd and calls ptsname(), chown(),
and chmod(). If FD_CLOEXEC is set for the fd, the fd passed for
/usr/lib/pt_chmod is already closed and /usr/lib/pt_chmod does not
work.
The following is their fix for the problem:
% gzcat ruby-2.2.2.tar.gz | tar tvf - | grep ruby-2.2.2/ext/pty/pty.c
-rw-r--r-- 1044/1044 22152 Nov 15 20:49 2014 ruby-2.2.2/ext/pty/pty.c
% cat -n ruby-2.2.2/ext/pty/pty.c | sed -n '221,223p;234,256p;330,341p;450p'
221 static int
222 get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg, int fail)
223 {
234 #if defined(__sun) || (defined(__FreeBSD__) && __FreeBSD_version < 902000)
235 /* workaround for Solaris 10: grantpt() doesn't work if FD_CLOEXEC is set. [ruby-dev:44688] */
236 /* FreeBSD 9.2 or later supports O_CLOEXEC
237 * http://www.freebsd.org/cgi/query-pr.cgi?pr=162374 */
238 if ((masterfd = posix_openpt(O_RDWR|O_NOCTTY)) == -1) goto error;
239 if (sigaction(SIGCHLD, &dfl, &old) == -1) goto error;
240 if (grantpt(masterfd) == -1) goto grantpt_error;
241 rb_fd_fix_cloexec(masterfd);
242 #else
243 {
244 int flags = O_RDWR|O_NOCTTY;
245 # if defined(O_CLOEXEC)
246 /* glibc posix_openpt() in GNU/Linux calls open("/dev/ptmx", flags) internally.
247 * So version dependency on GNU/Linux is same as O_CLOEXEC with open().
248 * O_CLOEXEC is available since Linux 2.6.23. Linux 2.6.18 silently ignore it. */
249 flags |= O_CLOEXEC;
250 # endif
251 if ((masterfd = posix_openpt(flags)) == -1) goto error;
252 }
253 rb_fd_fix_cloexec(masterfd);
254 if (sigaction(SIGCHLD, &dfl, &old) == -1) goto error;
255 if (grantpt(masterfd) == -1) goto grantpt_error;
256 #endif
330 #if defined(__sun)
331 /* workaround for Solaris 10: grantpt() doesn't work if FD_CLOEXEC is set. [ruby-dev:44688] */
332 if((masterfd = open("/dev/ptmx", O_RDWR, 0)) == -1) goto error;
333 s = signal(SIGCHLD, SIG_DFL);
334 if(grantpt(masterfd) == -1) goto error;
335 rb_fd_fix_cloexec(masterfd);
336 #else
337 if((masterfd = rb_cloexec_open("/dev/ptmx", O_RDWR, 0)) == -1) goto error;
338 rb_update_max_fd(masterfd);
339 s = signal(SIGCHLD, SIG_DFL);
340 if(grantpt(masterfd) == -1) goto error;
341 #endif
450 }
^ permalink raw reply [flat|nested] 8+ messages in thread* bug#20555: Emacs 24.2 vs 24.4 on Solaris: M-x shell and "tty => not a tty"
2015-05-12 6:08 ` bug#20555: " Paul Eggert
` (2 preceding siblings ...)
2015-06-02 16:45 ` 白井彰
@ 2015-06-11 23:48 ` Paul Eggert
3 siblings, 0 replies; 8+ messages in thread
From: Paul Eggert @ 2015-06-11 23:48 UTC (permalink / raw)
To: Akira Shirai; +Cc: Georges Ko, 20555-done, Warren, John W CIV (US)
[-- Attachment #1: Type: text/plain, Size: 234 bytes --]
Akira Shirai, thanks for the info about grantpt and its internal setuid program;
that made the problem obvious. I installed the attached patch into the Emacs
master sources and am (perhaps optimistically) marking this bug as done.
[-- Attachment #2: 0001-Fix-not-a-tty-bug-on-Solaris-10.patch --]
[-- Type: text/x-diff, Size: 3904 bytes --]
From 099cb9f7b8b1d00293298d947fc77b8c96120820 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 11 Jun 2015 16:41:36 -0700
Subject: [PATCH] Fix "not a tty" bug on Solaris 10
* configure.ac (PTY_OPEN): Define to plain 'open'
on SVR4-derived hosts, so that the O_CLOEXEC flag isn't set.
* src/process.c (allocate_pty): Set the O_CLOEXEC flag after
calling PTY_TTY_NAME_SPRINTF, for the benefit of SVR4-derived
hosts that call grantpt which does its work via a setuid subcommand
(Bug#19191, Bug#19927, Bug#20555, Bug#20686).
Also, set O_CLOEXEC even if PTY_OPEN is not defined, since it
seems relevant in that case too.
---
configure.ac | 5 ++++-
src/process.c | 20 +++++++++++---------
2 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/configure.ac b/configure.ac
index 9c6a74a..070b061 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4397,14 +4397,17 @@ case $opsys in
;;
sol2* )
- dnl On SysVr4, grantpt(3) forks a subprocess, so keep sigchld_handler()
+ dnl On SysVr4, grantpt(3) forks a subprocess, so do not use
+ dnl O_CLOEXEC when opening the pty, and keep the SIGCHLD handler
dnl from intercepting that death. If any child but grantpt's should die
dnl within, it should be caught after sigrelse(2).
+ AC_DEFINE(PTY_OPEN, [fd = open (pty_name, O_RDWR | O_NONBLOCK)])
AC_DEFINE(PTY_TTY_NAME_SPRINTF, [{ char *ptsname (int), *ptyname; int grantpt_result; sigset_t blocked; sigemptyset (&blocked); sigaddset (&blocked, SIGCHLD); pthread_sigmask (SIG_BLOCK, &blocked, 0); grantpt_result = grantpt (fd); pthread_sigmask (SIG_UNBLOCK, &blocked, 0); if (grantpt_result == -1 || unlockpt (fd) == -1 || !(ptyname = ptsname (fd))) { emacs_close (fd); return -1; } snprintf (pty_name, PTY_NAME_SIZE, "%s", ptyname); }])
;;
unixware )
dnl Comments are as per sol2*.
+ AC_DEFINE(PTY_OPEN, [fd = open (pty_name, O_RDWR | O_NONBLOCK)])
AC_DEFINE(PTY_TTY_NAME_SPRINTF, [{ char *ptsname (int), *ptyname; int grantpt_result; sigset_t blocked; sigemptyset (&blocked); sigaddset (&blocked, SIGCHLD); pthread_sigmask (SIG_BLOCK, &blocked, 0); grantpt_result = grantpt (fd); pthread_sigmask (SIG_UNBLOCK, &blocked, 0); if (grantpt_result == -1) fatal("could not grant slave pty"); if (unlockpt(fd) == -1) fatal("could not unlock slave pty"); if (!(ptyname = ptsname(fd))) fatal ("could not enable slave pty"); snprintf (pty_name, PTY_NAME_SIZE, "%s", ptyname); }])
;;
esac
diff --git a/src/process.c b/src/process.c
index 17fe708..b4f979f 100644
--- a/src/process.c
+++ b/src/process.c
@@ -658,22 +658,24 @@ allocate_pty (char pty_name[PTY_NAME_SIZE])
if (fd >= 0)
{
-#ifdef PTY_OPEN
+#ifdef PTY_TTY_NAME_SPRINTF
+ PTY_TTY_NAME_SPRINTF
+#else
+ sprintf (pty_name, "/dev/tty%c%x", c, i);
+#endif /* no PTY_TTY_NAME_SPRINTF */
+
/* Set FD's close-on-exec flag. This is needed even if
PT_OPEN calls posix_openpt with O_CLOEXEC, since POSIX
doesn't require support for that combination.
+ Do this after PTY_TTY_NAME_SPRINTF, which on some platforms
+ doesn't work if the close-on-exec flag is set (Bug#20555).
Multithreaded platforms where posix_openpt ignores
O_CLOEXEC (or where PTY_OPEN doesn't call posix_openpt)
have a race condition between the PTY_OPEN and here. */
fcntl (fd, F_SETFD, FD_CLOEXEC);
-#endif
- /* Check to make certain that both sides are available
- this avoids a nasty yet stupid bug in rlogins. */
-#ifdef PTY_TTY_NAME_SPRINTF
- PTY_TTY_NAME_SPRINTF
-#else
- sprintf (pty_name, "/dev/tty%c%x", c, i);
-#endif /* no PTY_TTY_NAME_SPRINTF */
+
+ /* Check to make certain that both sides are available.
+ This avoids a nasty yet stupid bug in rlogins. */
if (faccessat (AT_FDCWD, pty_name, R_OK | W_OK, AT_EACCESS) != 0)
{
emacs_close (fd);
--
2.1.0
^ permalink raw reply related [flat|nested] 8+ messages in thread