glibc/sysdeps/unix/sysv/linux/ttyname_r.c

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/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <termios.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <_itoa.h>
#include "ttyname.h"
static int getttyname_r (char *buf, size_t buflen,
linux ttyname{_r}: Make tty checks consistent In the ttyname and ttyname_r routines on Linux, at several points it needs to check if a given TTY is the TTY we are looking for. It used to be that this check was (to see if `maybe` is `mytty`): __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #else && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev #endif This check appears in several places. Then, one of the changes made in commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 was to change that check to: __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #endif && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev That is, it made the st_ino and st_dev parts of the check happen even if we have the st_rdev member. This is an important change, because the kernel allows multiple devpts filesystem instances to be created; a device file in one devpts instance may share the same st_rdev with a file in another devpts instance, but they aren't the same file. This check appears twice in each file (ttyname.c and ttyname_r.c), once (in ttyname and __ttyname_r) to check if a candidate file found by inspecting /proc is the desired TTY, and once (in getttyname and getttyname_r) to check if a candidate file found by searching /dev is the desired TTY. However, 15e9a4f only updated the checks for files found via /proc; but the concern about collisions between devpts instances is just as valid for files found via /dev. So, update all 4 occurrences the check to be consistent with the version of the check introduced in 15e9a4f. Make it easy to keep all 4 occurrences of the check consistent by pulling it in to a static inline function, is_mytty. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:34:30 +00:00
const struct stat64 *mytty, int save,
int *dostat);
static int
attribute_compat_text_section
linux ttyname{_r}: Make tty checks consistent In the ttyname and ttyname_r routines on Linux, at several points it needs to check if a given TTY is the TTY we are looking for. It used to be that this check was (to see if `maybe` is `mytty`): __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #else && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev #endif This check appears in several places. Then, one of the changes made in commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 was to change that check to: __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #endif && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev That is, it made the st_ino and st_dev parts of the check happen even if we have the st_rdev member. This is an important change, because the kernel allows multiple devpts filesystem instances to be created; a device file in one devpts instance may share the same st_rdev with a file in another devpts instance, but they aren't the same file. This check appears twice in each file (ttyname.c and ttyname_r.c), once (in ttyname and __ttyname_r) to check if a candidate file found by inspecting /proc is the desired TTY, and once (in getttyname and getttyname_r) to check if a candidate file found by searching /dev is the desired TTY. However, 15e9a4f only updated the checks for files found via /proc; but the concern about collisions between devpts instances is just as valid for files found via /dev. So, update all 4 occurrences the check to be consistent with the version of the check introduced in 15e9a4f. Make it easy to keep all 4 occurrences of the check consistent by pulling it in to a static inline function, is_mytty. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:34:30 +00:00
getttyname_r (char *buf, size_t buflen, const struct stat64 *mytty,
int save, int *dostat)
{
struct stat64 st;
DIR *dirstream;
struct dirent64 *d;
size_t devlen = strlen (buf);
Update. 1998-07-16 10:23 Ulrich Drepper <drepper@cygnus.com> * argp/argp-fmtstream.c: Unify names of used global functions. * argp/argp-help.c: Likewise. * assert/assert-perr.c: Likewise * assert/assert.c: Likewise * dirent/scandir.c: Likewise * dirent/scandir64.c: Likewise * dirent/versionsort.c: Likewise * dirent/versionsort64.c: Likewise * gmon/bb_exit_func.c: Likewise. * gmon/gmon.c: Likewise. * grp/initgroups.c: Likewise. * iconv/gconv_conf.c: Likewise. * inet/getnameinfo.c: Likewise. * inet/getnetgrent_r.c: Likewise. * inet/inet_ntoa.c: Likewise. * inet/rcmd.c: Likewise. * inet/rexec.c: Likewise. * inet/ruserpass.c: Likewise. * io/fts.c: Likewise. * io/ftw.c: Likewise. * io/ftw64.c: Likewise. * io/getdirname.c: Likewise. * io/getwd.c: Likewise. * io/lockf.c: Likewise. * libio/iofdopen.c: Likewise. * libio/iopopen.c: Likewise. * login/utmp_daemon.c: Likewise. * malloc/mtrace.c: Likewise. * malloc/obstack.c * misc/daemon.c: Likewise. * misc/efgcvt_r.c: Likewise. * misc/err.c: Likewise. * misc/error.c: Likewise. * misc/fstab.c: Likewise. * misc/getpass.c: Likewise. * misc/getttyent.c: Likewise. * misc/mntent_r.c: Likewise. * misc/search.h: Likewise. * misc/syslog.c: Likewise. * nscd/nscd_getgr_r.c: Likewise. * nscd/nscd_getpw_r.c: Likewise. * posix/getpgrp.c: Likewise. * posix/wordexp.c: Likewise. * pwd/fgetpwent_r.c: Likewise. * pwd/getpw.c: Likewise. * resolv/herror.c: Likewise. * resolv/res_init.c: Likewise. * shadow/fgetspent_r.c: Likewise. * shadow/lckpwdf.c: Likewise. * signal/sigrelse.c: Likewise. * stdio-common/asprintf.c: Likewise. * stdio-common/dprintf.c: Likewise. * stdio-common/getw.c: Likewise. * stdio-common/putw.c: Likewise. * stdio-common/snprintf.c: Likewise. * stdio-common/sprintf.c: Likewise. * stdio-common/sscanf.c: Likewise. * stdlib/lrand48_r.c: Likewise. * stdlib/mrand48_r.c: Likewise. * string/argz-replace.c: Likewise. * string/envz.c: Likewise. * sunrpc/auth_des.c: Likewise. * sunrpc/auth_unix.c: Likewise. * sunrpc/bindrsvprt.c: Likewise. * sunrpc/clnt_gen.c: Likewise. * sunrpc/clnt_perr.c: Likewise. * sunrpc/clnt_simp.c: Likewise. * sunrpc/clnt_tcp.c: Likewise. * sunrpc/clnt_udp.c: Likewise. * sunrpc/get_myaddr.c: Likewise. * sunrpc/key_call.c: Likewise. * sunrpc/netname.c: Likewise. * sunrpc/openchild.c: Likewise. * sunrpc/pmap_rmt.c: Likewise. * sunrpc/rpc_dtable.c: Likewise. * sunrpc/rtime.c: Likewise. * sunrpc/svc_run.c: Likewise. * sunrpc/svc_simple.c: Likewise. * sunrpc/svc_tcp.c: Likewise. * sunrpc/svc_udp.c: Likewise. * sunrpc/svcauth_des.c: Likewise. * sunrpc/xdr_array.c: Likewise. * sunrpc/xdr_rec.c: Likewise. * sunrpc/xdr_ref.c: Likewise. * sunrpc/xdr_stdio.c: Likewise. * sysdeps/generic/abort.c: Likewise. * sysdeps/generic/dl-sysdep.c: Likewise. * sysdeps/generic/fstatfs64.c: Likewise. * sysdeps/generic/ftruncate64.c: Likewise. * sysdeps/generic/getrlimit64.c: Likewise. * sysdeps/generic/glob.c: Likewise. * sysdeps/generic/prof-freq.c: Likewise. * sysdeps/generic/putenv.c: Likewise. * sysdeps/generic/statfs64.c: Likewise. * sysdeps/generic/ttyname_r.c: Likewise. * sysdeps/generic/utmp_file.c: Likewise. * sysdeps/generic/vlimit.c: Likewise. * sysdeps/generic/vtimes.c: Likewise. * sysdeps/posix/cuserid.c: Likewise. * sysdeps/posix/euidaccess.c: Likewise. * sysdeps/posix/mkstemp.c: Likewise. * sysdeps/posix/mktemp.c: Likewise. * sysdeps/posix/pread.c: Likewise. * sysdeps/posix/pread64.c: Likewise. * sysdeps/posix/profil.c: Likewise. * sysdeps/posix/pwrite.c: Likewise. * sysdeps/posix/pwrite64.c: Likewise. * sysdeps/posix/sigblock.c: Likewise. * sysdeps/posix/sigpause.c: Likewise. * sysdeps/posix/ttyname.c: Likewise. * sysdeps/posix/ttyname_r.c: Likewise. * sysdeps/posix/waitid.c: Likewise. * sysdeps/unix/getlogin_r.c: Likewise. * sysdeps/unix/grantpt.c: Likewise. * sysdeps/unix/rewinddir.c: Likewise. * sysdeps/unix/sysv/linux/gethostid.c: Likewise. * sysdeps/unix/sysv/linux/getpt.c: Likewise. * sysdeps/unix/sysv/linux/if_index.c: Likewise. * sysdeps/unix/sysv/linux/ptsname.c: Likewise. * sysdeps/unix/sysv/linux/sendmsg.c: Likewise. * sysdeps/unix/sysv/linux/statvfs.c: Likewise. * sysdeps/unix/sysv/linux/ttyname.c: Likewise. * sysdeps/unix/sysv/linux/ttyname_r.c: Likewise. * sysdeps/unix/sysv/linux/ulimit.c: Likewise. * sysdeps/unix/sysv/linux/unlockpt.c: Likewise. * sysvipc/sys/shm.h: Likewise. * time/ctime_r.c: Likewise. * time/strptime.c: Likewise. * wcsmbs/mbrlen.c: Likewise. * wcsmbs/wcsdup.c: Likewise. * wcsmbs/wcsxfrm.c: Likewise. * wctype/wcfuncs.c: Likewise. * sysdeps/unix/sysv/linux/i386/socker.S: Change to honor NO_WEAK_ALIAS. * sysdeps/unix/sysv/linux/accept.S: Don't generate __ name. * sysdeps/unix/sysv/linux/bind.S: Likewise. * sysdeps/unix/sysv/linux/getsockname.S: Likewise. * sysdeps/unix/sysv/linux/listen.S: Likewise. * sysdeps/unix/sysv/linux/recvfrom.S: Likewise. * sysdeps/unix/sysv/linux/sendto.S: Likewise. * sysdeps/unix/sysv/linux/setsockopt.S: Likewise. * grp/fgetgrent_r.c: Use explicit locking of the stream. * elf/Makefile (rtld-routines): Add dl-environ. * sysdeps/generic/dl-environ.c: New file. * libio/Makefile [REENTRANT] (routines): Add iofputs_u. * libio/Versions: Add fputs_unlocked. * libio/iofputs_u.c: New file. * libio/stdio.h: Add prototype for fputs_unlocked. * sunrpc/rpc/auth.h: Use __PMT instead of __P in type definitions. * sunrpc/rpc/clnt.h: Likewise. * sunrpc/rpc/pmap_clnt.h: Likewise. * sunrpc/rpc/svc.h: Likewise. * sunrpc/rpc/xdr.h: Likewise. * sysdeps/i386/memchr.S: Correct for more strict gas. * sysdeps/i386/fpu/bits/mathinline.h: Likewise. * sysdeps/libm-i387/i686/s_fdim.S: Likewise. * sysdeps/libm-i387/i686/s_fdimf.S: Likewise. * sysdeps/libm-i387/i686/s_fdiml.S: Likewise. 1998-07-15 Andreas Jaeger <aj@arthur.rhein-neckar.de> * configure.in: Change message for binutils version from 2.8.1.0.17->2.8.1.0.23. 1998-07-15 Ulrich Drepper <drepper@cygnus.com> * sysdeps/unix/sysv/sysv4/solaris2/sparc/sysdep.h: Define LOC. Patch by John Tobey <jtobey@banta-im.com>.
1998-07-16 11:44:36 +00:00
dirstream = __opendir (buf);
if (dirstream == NULL)
{
*dostat = -1;
return errno;
}
while ((d = __readdir64 (dirstream)) != NULL)
linux ttyname{_r}: Make tty checks consistent In the ttyname and ttyname_r routines on Linux, at several points it needs to check if a given TTY is the TTY we are looking for. It used to be that this check was (to see if `maybe` is `mytty`): __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #else && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev #endif This check appears in several places. Then, one of the changes made in commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 was to change that check to: __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #endif && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev That is, it made the st_ino and st_dev parts of the check happen even if we have the st_rdev member. This is an important change, because the kernel allows multiple devpts filesystem instances to be created; a device file in one devpts instance may share the same st_rdev with a file in another devpts instance, but they aren't the same file. This check appears twice in each file (ttyname.c and ttyname_r.c), once (in ttyname and __ttyname_r) to check if a candidate file found by inspecting /proc is the desired TTY, and once (in getttyname and getttyname_r) to check if a candidate file found by searching /dev is the desired TTY. However, 15e9a4f only updated the checks for files found via /proc; but the concern about collisions between devpts instances is just as valid for files found via /dev. So, update all 4 occurrences the check to be consistent with the version of the check introduced in 15e9a4f. Make it easy to keep all 4 occurrences of the check consistent by pulling it in to a static inline function, is_mytty. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:34:30 +00:00
if ((d->d_fileno == mytty->st_ino || *dostat)
&& strcmp (d->d_name, "stdin")
&& strcmp (d->d_name, "stdout")
&& strcmp (d->d_name, "stderr"))
{
char *cp;
size_t needed = _D_EXACT_NAMLEN (d) + 1;
if (needed > buflen)
{
*dostat = -1;
Update. 1998-07-16 10:23 Ulrich Drepper <drepper@cygnus.com> * argp/argp-fmtstream.c: Unify names of used global functions. * argp/argp-help.c: Likewise. * assert/assert-perr.c: Likewise * assert/assert.c: Likewise * dirent/scandir.c: Likewise * dirent/scandir64.c: Likewise * dirent/versionsort.c: Likewise * dirent/versionsort64.c: Likewise * gmon/bb_exit_func.c: Likewise. * gmon/gmon.c: Likewise. * grp/initgroups.c: Likewise. * iconv/gconv_conf.c: Likewise. * inet/getnameinfo.c: Likewise. * inet/getnetgrent_r.c: Likewise. * inet/inet_ntoa.c: Likewise. * inet/rcmd.c: Likewise. * inet/rexec.c: Likewise. * inet/ruserpass.c: Likewise. * io/fts.c: Likewise. * io/ftw.c: Likewise. * io/ftw64.c: Likewise. * io/getdirname.c: Likewise. * io/getwd.c: Likewise. * io/lockf.c: Likewise. * libio/iofdopen.c: Likewise. * libio/iopopen.c: Likewise. * login/utmp_daemon.c: Likewise. * malloc/mtrace.c: Likewise. * malloc/obstack.c * misc/daemon.c: Likewise. * misc/efgcvt_r.c: Likewise. * misc/err.c: Likewise. * misc/error.c: Likewise. * misc/fstab.c: Likewise. * misc/getpass.c: Likewise. * misc/getttyent.c: Likewise. * misc/mntent_r.c: Likewise. * misc/search.h: Likewise. * misc/syslog.c: Likewise. * nscd/nscd_getgr_r.c: Likewise. * nscd/nscd_getpw_r.c: Likewise. * posix/getpgrp.c: Likewise. * posix/wordexp.c: Likewise. * pwd/fgetpwent_r.c: Likewise. * pwd/getpw.c: Likewise. * resolv/herror.c: Likewise. * resolv/res_init.c: Likewise. * shadow/fgetspent_r.c: Likewise. * shadow/lckpwdf.c: Likewise. * signal/sigrelse.c: Likewise. * stdio-common/asprintf.c: Likewise. * stdio-common/dprintf.c: Likewise. * stdio-common/getw.c: Likewise. * stdio-common/putw.c: Likewise. * stdio-common/snprintf.c: Likewise. * stdio-common/sprintf.c: Likewise. * stdio-common/sscanf.c: Likewise. * stdlib/lrand48_r.c: Likewise. * stdlib/mrand48_r.c: Likewise. * string/argz-replace.c: Likewise. * string/envz.c: Likewise. * sunrpc/auth_des.c: Likewise. * sunrpc/auth_unix.c: Likewise. * sunrpc/bindrsvprt.c: Likewise. * sunrpc/clnt_gen.c: Likewise. * sunrpc/clnt_perr.c: Likewise. * sunrpc/clnt_simp.c: Likewise. * sunrpc/clnt_tcp.c: Likewise. * sunrpc/clnt_udp.c: Likewise. * sunrpc/get_myaddr.c: Likewise. * sunrpc/key_call.c: Likewise. * sunrpc/netname.c: Likewise. * sunrpc/openchild.c: Likewise. * sunrpc/pmap_rmt.c: Likewise. * sunrpc/rpc_dtable.c: Likewise. * sunrpc/rtime.c: Likewise. * sunrpc/svc_run.c: Likewise. * sunrpc/svc_simple.c: Likewise. * sunrpc/svc_tcp.c: Likewise. * sunrpc/svc_udp.c: Likewise. * sunrpc/svcauth_des.c: Likewise. * sunrpc/xdr_array.c: Likewise. * sunrpc/xdr_rec.c: Likewise. * sunrpc/xdr_ref.c: Likewise. * sunrpc/xdr_stdio.c: Likewise. * sysdeps/generic/abort.c: Likewise. * sysdeps/generic/dl-sysdep.c: Likewise. * sysdeps/generic/fstatfs64.c: Likewise. * sysdeps/generic/ftruncate64.c: Likewise. * sysdeps/generic/getrlimit64.c: Likewise. * sysdeps/generic/glob.c: Likewise. * sysdeps/generic/prof-freq.c: Likewise. * sysdeps/generic/putenv.c: Likewise. * sysdeps/generic/statfs64.c: Likewise. * sysdeps/generic/ttyname_r.c: Likewise. * sysdeps/generic/utmp_file.c: Likewise. * sysdeps/generic/vlimit.c: Likewise. * sysdeps/generic/vtimes.c: Likewise. * sysdeps/posix/cuserid.c: Likewise. * sysdeps/posix/euidaccess.c: Likewise. * sysdeps/posix/mkstemp.c: Likewise. * sysdeps/posix/mktemp.c: Likewise. * sysdeps/posix/pread.c: Likewise. * sysdeps/posix/pread64.c: Likewise. * sysdeps/posix/profil.c: Likewise. * sysdeps/posix/pwrite.c: Likewise. * sysdeps/posix/pwrite64.c: Likewise. * sysdeps/posix/sigblock.c: Likewise. * sysdeps/posix/sigpause.c: Likewise. * sysdeps/posix/ttyname.c: Likewise. * sysdeps/posix/ttyname_r.c: Likewise. * sysdeps/posix/waitid.c: Likewise. * sysdeps/unix/getlogin_r.c: Likewise. * sysdeps/unix/grantpt.c: Likewise. * sysdeps/unix/rewinddir.c: Likewise. * sysdeps/unix/sysv/linux/gethostid.c: Likewise. * sysdeps/unix/sysv/linux/getpt.c: Likewise. * sysdeps/unix/sysv/linux/if_index.c: Likewise. * sysdeps/unix/sysv/linux/ptsname.c: Likewise. * sysdeps/unix/sysv/linux/sendmsg.c: Likewise. * sysdeps/unix/sysv/linux/statvfs.c: Likewise. * sysdeps/unix/sysv/linux/ttyname.c: Likewise. * sysdeps/unix/sysv/linux/ttyname_r.c: Likewise. * sysdeps/unix/sysv/linux/ulimit.c: Likewise. * sysdeps/unix/sysv/linux/unlockpt.c: Likewise. * sysvipc/sys/shm.h: Likewise. * time/ctime_r.c: Likewise. * time/strptime.c: Likewise. * wcsmbs/mbrlen.c: Likewise. * wcsmbs/wcsdup.c: Likewise. * wcsmbs/wcsxfrm.c: Likewise. * wctype/wcfuncs.c: Likewise. * sysdeps/unix/sysv/linux/i386/socker.S: Change to honor NO_WEAK_ALIAS. * sysdeps/unix/sysv/linux/accept.S: Don't generate __ name. * sysdeps/unix/sysv/linux/bind.S: Likewise. * sysdeps/unix/sysv/linux/getsockname.S: Likewise. * sysdeps/unix/sysv/linux/listen.S: Likewise. * sysdeps/unix/sysv/linux/recvfrom.S: Likewise. * sysdeps/unix/sysv/linux/sendto.S: Likewise. * sysdeps/unix/sysv/linux/setsockopt.S: Likewise. * grp/fgetgrent_r.c: Use explicit locking of the stream. * elf/Makefile (rtld-routines): Add dl-environ. * sysdeps/generic/dl-environ.c: New file. * libio/Makefile [REENTRANT] (routines): Add iofputs_u. * libio/Versions: Add fputs_unlocked. * libio/iofputs_u.c: New file. * libio/stdio.h: Add prototype for fputs_unlocked. * sunrpc/rpc/auth.h: Use __PMT instead of __P in type definitions. * sunrpc/rpc/clnt.h: Likewise. * sunrpc/rpc/pmap_clnt.h: Likewise. * sunrpc/rpc/svc.h: Likewise. * sunrpc/rpc/xdr.h: Likewise. * sysdeps/i386/memchr.S: Correct for more strict gas. * sysdeps/i386/fpu/bits/mathinline.h: Likewise. * sysdeps/libm-i387/i686/s_fdim.S: Likewise. * sysdeps/libm-i387/i686/s_fdimf.S: Likewise. * sysdeps/libm-i387/i686/s_fdiml.S: Likewise. 1998-07-15 Andreas Jaeger <aj@arthur.rhein-neckar.de> * configure.in: Change message for binutils version from 2.8.1.0.17->2.8.1.0.23. 1998-07-15 Ulrich Drepper <drepper@cygnus.com> * sysdeps/unix/sysv/sysv4/solaris2/sparc/sysdep.h: Define LOC. Patch by John Tobey <jtobey@banta-im.com>.
1998-07-16 11:44:36 +00:00
(void) __closedir (dirstream);
__set_errno (ERANGE);
return ERANGE;
}
cp = __stpncpy (buf + devlen, d->d_name, needed);
cp[0] = '\0';
if (__xstat64 (_STAT_VER, buf, &st) == 0
linux ttyname{_r}: Make tty checks consistent In the ttyname and ttyname_r routines on Linux, at several points it needs to check if a given TTY is the TTY we are looking for. It used to be that this check was (to see if `maybe` is `mytty`): __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #else && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev #endif This check appears in several places. Then, one of the changes made in commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 was to change that check to: __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #endif && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev That is, it made the st_ino and st_dev parts of the check happen even if we have the st_rdev member. This is an important change, because the kernel allows multiple devpts filesystem instances to be created; a device file in one devpts instance may share the same st_rdev with a file in another devpts instance, but they aren't the same file. This check appears twice in each file (ttyname.c and ttyname_r.c), once (in ttyname and __ttyname_r) to check if a candidate file found by inspecting /proc is the desired TTY, and once (in getttyname and getttyname_r) to check if a candidate file found by searching /dev is the desired TTY. However, 15e9a4f only updated the checks for files found via /proc; but the concern about collisions between devpts instances is just as valid for files found via /dev. So, update all 4 occurrences the check to be consistent with the version of the check introduced in 15e9a4f. Make it easy to keep all 4 occurrences of the check consistent by pulling it in to a static inline function, is_mytty. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:34:30 +00:00
&& is_mytty (mytty, &st))
{
Update. 1998-07-16 10:23 Ulrich Drepper <drepper@cygnus.com> * argp/argp-fmtstream.c: Unify names of used global functions. * argp/argp-help.c: Likewise. * assert/assert-perr.c: Likewise * assert/assert.c: Likewise * dirent/scandir.c: Likewise * dirent/scandir64.c: Likewise * dirent/versionsort.c: Likewise * dirent/versionsort64.c: Likewise * gmon/bb_exit_func.c: Likewise. * gmon/gmon.c: Likewise. * grp/initgroups.c: Likewise. * iconv/gconv_conf.c: Likewise. * inet/getnameinfo.c: Likewise. * inet/getnetgrent_r.c: Likewise. * inet/inet_ntoa.c: Likewise. * inet/rcmd.c: Likewise. * inet/rexec.c: Likewise. * inet/ruserpass.c: Likewise. * io/fts.c: Likewise. * io/ftw.c: Likewise. * io/ftw64.c: Likewise. * io/getdirname.c: Likewise. * io/getwd.c: Likewise. * io/lockf.c: Likewise. * libio/iofdopen.c: Likewise. * libio/iopopen.c: Likewise. * login/utmp_daemon.c: Likewise. * malloc/mtrace.c: Likewise. * malloc/obstack.c * misc/daemon.c: Likewise. * misc/efgcvt_r.c: Likewise. * misc/err.c: Likewise. * misc/error.c: Likewise. * misc/fstab.c: Likewise. * misc/getpass.c: Likewise. * misc/getttyent.c: Likewise. * misc/mntent_r.c: Likewise. * misc/search.h: Likewise. * misc/syslog.c: Likewise. * nscd/nscd_getgr_r.c: Likewise. * nscd/nscd_getpw_r.c: Likewise. * posix/getpgrp.c: Likewise. * posix/wordexp.c: Likewise. * pwd/fgetpwent_r.c: Likewise. * pwd/getpw.c: Likewise. * resolv/herror.c: Likewise. * resolv/res_init.c: Likewise. * shadow/fgetspent_r.c: Likewise. * shadow/lckpwdf.c: Likewise. * signal/sigrelse.c: Likewise. * stdio-common/asprintf.c: Likewise. * stdio-common/dprintf.c: Likewise. * stdio-common/getw.c: Likewise. * stdio-common/putw.c: Likewise. * stdio-common/snprintf.c: Likewise. * stdio-common/sprintf.c: Likewise. * stdio-common/sscanf.c: Likewise. * stdlib/lrand48_r.c: Likewise. * stdlib/mrand48_r.c: Likewise. * string/argz-replace.c: Likewise. * string/envz.c: Likewise. * sunrpc/auth_des.c: Likewise. * sunrpc/auth_unix.c: Likewise. * sunrpc/bindrsvprt.c: Likewise. * sunrpc/clnt_gen.c: Likewise. * sunrpc/clnt_perr.c: Likewise. * sunrpc/clnt_simp.c: Likewise. * sunrpc/clnt_tcp.c: Likewise. * sunrpc/clnt_udp.c: Likewise. * sunrpc/get_myaddr.c: Likewise. * sunrpc/key_call.c: Likewise. * sunrpc/netname.c: Likewise. * sunrpc/openchild.c: Likewise. * sunrpc/pmap_rmt.c: Likewise. * sunrpc/rpc_dtable.c: Likewise. * sunrpc/rtime.c: Likewise. * sunrpc/svc_run.c: Likewise. * sunrpc/svc_simple.c: Likewise. * sunrpc/svc_tcp.c: Likewise. * sunrpc/svc_udp.c: Likewise. * sunrpc/svcauth_des.c: Likewise. * sunrpc/xdr_array.c: Likewise. * sunrpc/xdr_rec.c: Likewise. * sunrpc/xdr_ref.c: Likewise. * sunrpc/xdr_stdio.c: Likewise. * sysdeps/generic/abort.c: Likewise. * sysdeps/generic/dl-sysdep.c: Likewise. * sysdeps/generic/fstatfs64.c: Likewise. * sysdeps/generic/ftruncate64.c: Likewise. * sysdeps/generic/getrlimit64.c: Likewise. * sysdeps/generic/glob.c: Likewise. * sysdeps/generic/prof-freq.c: Likewise. * sysdeps/generic/putenv.c: Likewise. * sysdeps/generic/statfs64.c: Likewise. * sysdeps/generic/ttyname_r.c: Likewise. * sysdeps/generic/utmp_file.c: Likewise. * sysdeps/generic/vlimit.c: Likewise. * sysdeps/generic/vtimes.c: Likewise. * sysdeps/posix/cuserid.c: Likewise. * sysdeps/posix/euidaccess.c: Likewise. * sysdeps/posix/mkstemp.c: Likewise. * sysdeps/posix/mktemp.c: Likewise. * sysdeps/posix/pread.c: Likewise. * sysdeps/posix/pread64.c: Likewise. * sysdeps/posix/profil.c: Likewise. * sysdeps/posix/pwrite.c: Likewise. * sysdeps/posix/pwrite64.c: Likewise. * sysdeps/posix/sigblock.c: Likewise. * sysdeps/posix/sigpause.c: Likewise. * sysdeps/posix/ttyname.c: Likewise. * sysdeps/posix/ttyname_r.c: Likewise. * sysdeps/posix/waitid.c: Likewise. * sysdeps/unix/getlogin_r.c: Likewise. * sysdeps/unix/grantpt.c: Likewise. * sysdeps/unix/rewinddir.c: Likewise. * sysdeps/unix/sysv/linux/gethostid.c: Likewise. * sysdeps/unix/sysv/linux/getpt.c: Likewise. * sysdeps/unix/sysv/linux/if_index.c: Likewise. * sysdeps/unix/sysv/linux/ptsname.c: Likewise. * sysdeps/unix/sysv/linux/sendmsg.c: Likewise. * sysdeps/unix/sysv/linux/statvfs.c: Likewise. * sysdeps/unix/sysv/linux/ttyname.c: Likewise. * sysdeps/unix/sysv/linux/ttyname_r.c: Likewise. * sysdeps/unix/sysv/linux/ulimit.c: Likewise. * sysdeps/unix/sysv/linux/unlockpt.c: Likewise. * sysvipc/sys/shm.h: Likewise. * time/ctime_r.c: Likewise. * time/strptime.c: Likewise. * wcsmbs/mbrlen.c: Likewise. * wcsmbs/wcsdup.c: Likewise. * wcsmbs/wcsxfrm.c: Likewise. * wctype/wcfuncs.c: Likewise. * sysdeps/unix/sysv/linux/i386/socker.S: Change to honor NO_WEAK_ALIAS. * sysdeps/unix/sysv/linux/accept.S: Don't generate __ name. * sysdeps/unix/sysv/linux/bind.S: Likewise. * sysdeps/unix/sysv/linux/getsockname.S: Likewise. * sysdeps/unix/sysv/linux/listen.S: Likewise. * sysdeps/unix/sysv/linux/recvfrom.S: Likewise. * sysdeps/unix/sysv/linux/sendto.S: Likewise. * sysdeps/unix/sysv/linux/setsockopt.S: Likewise. * grp/fgetgrent_r.c: Use explicit locking of the stream. * elf/Makefile (rtld-routines): Add dl-environ. * sysdeps/generic/dl-environ.c: New file. * libio/Makefile [REENTRANT] (routines): Add iofputs_u. * libio/Versions: Add fputs_unlocked. * libio/iofputs_u.c: New file. * libio/stdio.h: Add prototype for fputs_unlocked. * sunrpc/rpc/auth.h: Use __PMT instead of __P in type definitions. * sunrpc/rpc/clnt.h: Likewise. * sunrpc/rpc/pmap_clnt.h: Likewise. * sunrpc/rpc/svc.h: Likewise. * sunrpc/rpc/xdr.h: Likewise. * sysdeps/i386/memchr.S: Correct for more strict gas. * sysdeps/i386/fpu/bits/mathinline.h: Likewise. * sysdeps/libm-i387/i686/s_fdim.S: Likewise. * sysdeps/libm-i387/i686/s_fdimf.S: Likewise. * sysdeps/libm-i387/i686/s_fdiml.S: Likewise. 1998-07-15 Andreas Jaeger <aj@arthur.rhein-neckar.de> * configure.in: Change message for binutils version from 2.8.1.0.17->2.8.1.0.23. 1998-07-15 Ulrich Drepper <drepper@cygnus.com> * sysdeps/unix/sysv/sysv4/solaris2/sparc/sysdep.h: Define LOC. Patch by John Tobey <jtobey@banta-im.com>.
1998-07-16 11:44:36 +00:00
(void) __closedir (dirstream);
__set_errno (save);
return 0;
}
}
Update. 1998-07-16 10:23 Ulrich Drepper <drepper@cygnus.com> * argp/argp-fmtstream.c: Unify names of used global functions. * argp/argp-help.c: Likewise. * assert/assert-perr.c: Likewise * assert/assert.c: Likewise * dirent/scandir.c: Likewise * dirent/scandir64.c: Likewise * dirent/versionsort.c: Likewise * dirent/versionsort64.c: Likewise * gmon/bb_exit_func.c: Likewise. * gmon/gmon.c: Likewise. * grp/initgroups.c: Likewise. * iconv/gconv_conf.c: Likewise. * inet/getnameinfo.c: Likewise. * inet/getnetgrent_r.c: Likewise. * inet/inet_ntoa.c: Likewise. * inet/rcmd.c: Likewise. * inet/rexec.c: Likewise. * inet/ruserpass.c: Likewise. * io/fts.c: Likewise. * io/ftw.c: Likewise. * io/ftw64.c: Likewise. * io/getdirname.c: Likewise. * io/getwd.c: Likewise. * io/lockf.c: Likewise. * libio/iofdopen.c: Likewise. * libio/iopopen.c: Likewise. * login/utmp_daemon.c: Likewise. * malloc/mtrace.c: Likewise. * malloc/obstack.c * misc/daemon.c: Likewise. * misc/efgcvt_r.c: Likewise. * misc/err.c: Likewise. * misc/error.c: Likewise. * misc/fstab.c: Likewise. * misc/getpass.c: Likewise. * misc/getttyent.c: Likewise. * misc/mntent_r.c: Likewise. * misc/search.h: Likewise. * misc/syslog.c: Likewise. * nscd/nscd_getgr_r.c: Likewise. * nscd/nscd_getpw_r.c: Likewise. * posix/getpgrp.c: Likewise. * posix/wordexp.c: Likewise. * pwd/fgetpwent_r.c: Likewise. * pwd/getpw.c: Likewise. * resolv/herror.c: Likewise. * resolv/res_init.c: Likewise. * shadow/fgetspent_r.c: Likewise. * shadow/lckpwdf.c: Likewise. * signal/sigrelse.c: Likewise. * stdio-common/asprintf.c: Likewise. * stdio-common/dprintf.c: Likewise. * stdio-common/getw.c: Likewise. * stdio-common/putw.c: Likewise. * stdio-common/snprintf.c: Likewise. * stdio-common/sprintf.c: Likewise. * stdio-common/sscanf.c: Likewise. * stdlib/lrand48_r.c: Likewise. * stdlib/mrand48_r.c: Likewise. * string/argz-replace.c: Likewise. * string/envz.c: Likewise. * sunrpc/auth_des.c: Likewise. * sunrpc/auth_unix.c: Likewise. * sunrpc/bindrsvprt.c: Likewise. * sunrpc/clnt_gen.c: Likewise. * sunrpc/clnt_perr.c: Likewise. * sunrpc/clnt_simp.c: Likewise. * sunrpc/clnt_tcp.c: Likewise. * sunrpc/clnt_udp.c: Likewise. * sunrpc/get_myaddr.c: Likewise. * sunrpc/key_call.c: Likewise. * sunrpc/netname.c: Likewise. * sunrpc/openchild.c: Likewise. * sunrpc/pmap_rmt.c: Likewise. * sunrpc/rpc_dtable.c: Likewise. * sunrpc/rtime.c: Likewise. * sunrpc/svc_run.c: Likewise. * sunrpc/svc_simple.c: Likewise. * sunrpc/svc_tcp.c: Likewise. * sunrpc/svc_udp.c: Likewise. * sunrpc/svcauth_des.c: Likewise. * sunrpc/xdr_array.c: Likewise. * sunrpc/xdr_rec.c: Likewise. * sunrpc/xdr_ref.c: Likewise. * sunrpc/xdr_stdio.c: Likewise. * sysdeps/generic/abort.c: Likewise. * sysdeps/generic/dl-sysdep.c: Likewise. * sysdeps/generic/fstatfs64.c: Likewise. * sysdeps/generic/ftruncate64.c: Likewise. * sysdeps/generic/getrlimit64.c: Likewise. * sysdeps/generic/glob.c: Likewise. * sysdeps/generic/prof-freq.c: Likewise. * sysdeps/generic/putenv.c: Likewise. * sysdeps/generic/statfs64.c: Likewise. * sysdeps/generic/ttyname_r.c: Likewise. * sysdeps/generic/utmp_file.c: Likewise. * sysdeps/generic/vlimit.c: Likewise. * sysdeps/generic/vtimes.c: Likewise. * sysdeps/posix/cuserid.c: Likewise. * sysdeps/posix/euidaccess.c: Likewise. * sysdeps/posix/mkstemp.c: Likewise. * sysdeps/posix/mktemp.c: Likewise. * sysdeps/posix/pread.c: Likewise. * sysdeps/posix/pread64.c: Likewise. * sysdeps/posix/profil.c: Likewise. * sysdeps/posix/pwrite.c: Likewise. * sysdeps/posix/pwrite64.c: Likewise. * sysdeps/posix/sigblock.c: Likewise. * sysdeps/posix/sigpause.c: Likewise. * sysdeps/posix/ttyname.c: Likewise. * sysdeps/posix/ttyname_r.c: Likewise. * sysdeps/posix/waitid.c: Likewise. * sysdeps/unix/getlogin_r.c: Likewise. * sysdeps/unix/grantpt.c: Likewise. * sysdeps/unix/rewinddir.c: Likewise. * sysdeps/unix/sysv/linux/gethostid.c: Likewise. * sysdeps/unix/sysv/linux/getpt.c: Likewise. * sysdeps/unix/sysv/linux/if_index.c: Likewise. * sysdeps/unix/sysv/linux/ptsname.c: Likewise. * sysdeps/unix/sysv/linux/sendmsg.c: Likewise. * sysdeps/unix/sysv/linux/statvfs.c: Likewise. * sysdeps/unix/sysv/linux/ttyname.c: Likewise. * sysdeps/unix/sysv/linux/ttyname_r.c: Likewise. * sysdeps/unix/sysv/linux/ulimit.c: Likewise. * sysdeps/unix/sysv/linux/unlockpt.c: Likewise. * sysvipc/sys/shm.h: Likewise. * time/ctime_r.c: Likewise. * time/strptime.c: Likewise. * wcsmbs/mbrlen.c: Likewise. * wcsmbs/wcsdup.c: Likewise. * wcsmbs/wcsxfrm.c: Likewise. * wctype/wcfuncs.c: Likewise. * sysdeps/unix/sysv/linux/i386/socker.S: Change to honor NO_WEAK_ALIAS. * sysdeps/unix/sysv/linux/accept.S: Don't generate __ name. * sysdeps/unix/sysv/linux/bind.S: Likewise. * sysdeps/unix/sysv/linux/getsockname.S: Likewise. * sysdeps/unix/sysv/linux/listen.S: Likewise. * sysdeps/unix/sysv/linux/recvfrom.S: Likewise. * sysdeps/unix/sysv/linux/sendto.S: Likewise. * sysdeps/unix/sysv/linux/setsockopt.S: Likewise. * grp/fgetgrent_r.c: Use explicit locking of the stream. * elf/Makefile (rtld-routines): Add dl-environ. * sysdeps/generic/dl-environ.c: New file. * libio/Makefile [REENTRANT] (routines): Add iofputs_u. * libio/Versions: Add fputs_unlocked. * libio/iofputs_u.c: New file. * libio/stdio.h: Add prototype for fputs_unlocked. * sunrpc/rpc/auth.h: Use __PMT instead of __P in type definitions. * sunrpc/rpc/clnt.h: Likewise. * sunrpc/rpc/pmap_clnt.h: Likewise. * sunrpc/rpc/svc.h: Likewise. * sunrpc/rpc/xdr.h: Likewise. * sysdeps/i386/memchr.S: Correct for more strict gas. * sysdeps/i386/fpu/bits/mathinline.h: Likewise. * sysdeps/libm-i387/i686/s_fdim.S: Likewise. * sysdeps/libm-i387/i686/s_fdimf.S: Likewise. * sysdeps/libm-i387/i686/s_fdiml.S: Likewise. 1998-07-15 Andreas Jaeger <aj@arthur.rhein-neckar.de> * configure.in: Change message for binutils version from 2.8.1.0.17->2.8.1.0.23. 1998-07-15 Ulrich Drepper <drepper@cygnus.com> * sysdeps/unix/sysv/sysv4/solaris2/sparc/sysdep.h: Define LOC. Patch by John Tobey <jtobey@banta-im.com>.
1998-07-16 11:44:36 +00:00
(void) __closedir (dirstream);
__set_errno (save);
/* It is not clear what to return in this case. `isatty' says FD
refers to a TTY but no entry in /dev has this inode. */
return ENOTTY;
}
/* Store at most BUFLEN character of the pathname of the terminal FD is
open on in BUF. Return 0 on success, otherwise an error number. */
int
__ttyname_r (int fd, char *buf, size_t buflen)
{
char procname[30];
struct stat64 st, st1;
int dostat = 0;
linux ttyname{_r}: Don't bail prematurely [BZ #22145] Commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 introduced logic for ttyname() sending back ENODEV to signal that we can't get a name for the TTY because we inherited it from a different mount namespace. However, just because we inherited it from a different mount namespace and it isn't available at its original path, doesn't mean that its name is unknowable; we can still try to find it by allowing the normal fall back on iterating through devices. An example scenario where this happens is with "/dev/console" in containers. It's a common practice among container managers to allocate a PTY master/slave pair in the host's mount namespace (the slave having a path like "/dev/pty/$X"), bind mount the slave to "/dev/console" in the container's mount namespace, and send the slave FD to a process in the container. Inside of the container, the slave-end isn't available at its original path ("/dev/pts/$X"), since the container mount namespace has a separate devpts instance from the host (that path may or may not exist in the container; if it does exist, it's not the same PTY slave device). Currently ttyname{_r} sees that the file at the original "/dev/pts/$X" path doesn't match the FD passed to it, and fails early and gives up, even though if it kept searching it would find the TTY at "/dev/console". Fix that; don't have the ENODEV path force an early return inhibiting the fall-back search. This change is based on the previous patch that adds use of is_mytty in getttyname and getttyname_r. Without that change, this effectively reverts 15e9a4f, which made us disregard the false similarity of file pointed to by "/proc/self/fd/$Y", because if it doesn't bail prematurely then that file ("/dev/pts/$X") will just come up again anyway in the fall-back search. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:36:44 +00:00
int doispty = 0;
int save = errno;
/* Test for the absolute minimal size. This makes life easier inside
the loop. */
if (!buf)
{
__set_errno (EINVAL);
return EINVAL;
}
if (buflen < sizeof ("/dev/pts/"))
{
__set_errno (ERANGE);
return ERANGE;
}
/* isatty check, tcgetattr is used because it sets the correct
errno (EBADF resp. ENOTTY) on error. */
struct termios term;
if (__glibc_unlikely (__tcgetattr (fd, &term) < 0))
return errno;
if (__fxstat64 (_STAT_VER, fd, &st) < 0)
return errno;
/* We try using the /proc filesystem. */
*_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';
ssize_t ret = __readlink (procname, buf, buflen - 1);
if (__glibc_unlikely (ret == -1 && errno == ENAMETOOLONG))
{
__set_errno (ERANGE);
return ERANGE;
}
if (__glibc_likely (ret != -1))
{
#define UNREACHABLE_LEN strlen ("(unreachable)")
if (ret > UNREACHABLE_LEN
&& memcmp (buf, "(unreachable)", UNREACHABLE_LEN) == 0)
{
memmove (buf, buf + UNREACHABLE_LEN, ret - UNREACHABLE_LEN);
ret -= UNREACHABLE_LEN;
}
/* readlink need not terminate the string. */
buf[ret] = '\0';
/* Verify readlink result, fall back on iterating through devices. */
if (buf[0] == '/'
&& __xstat64 (_STAT_VER, buf, &st1) == 0
linux ttyname{_r}: Make tty checks consistent In the ttyname and ttyname_r routines on Linux, at several points it needs to check if a given TTY is the TTY we are looking for. It used to be that this check was (to see if `maybe` is `mytty`): __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #else && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev #endif This check appears in several places. Then, one of the changes made in commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 was to change that check to: __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #endif && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev That is, it made the st_ino and st_dev parts of the check happen even if we have the st_rdev member. This is an important change, because the kernel allows multiple devpts filesystem instances to be created; a device file in one devpts instance may share the same st_rdev with a file in another devpts instance, but they aren't the same file. This check appears twice in each file (ttyname.c and ttyname_r.c), once (in ttyname and __ttyname_r) to check if a candidate file found by inspecting /proc is the desired TTY, and once (in getttyname and getttyname_r) to check if a candidate file found by searching /dev is the desired TTY. However, 15e9a4f only updated the checks for files found via /proc; but the concern about collisions between devpts instances is just as valid for files found via /dev. So, update all 4 occurrences the check to be consistent with the version of the check introduced in 15e9a4f. Make it easy to keep all 4 occurrences of the check consistent by pulling it in to a static inline function, is_mytty. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:34:30 +00:00
&& is_mytty (&st, &st1))
return 0;
linux ttyname{_r}: Don't bail prematurely [BZ #22145] Commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 introduced logic for ttyname() sending back ENODEV to signal that we can't get a name for the TTY because we inherited it from a different mount namespace. However, just because we inherited it from a different mount namespace and it isn't available at its original path, doesn't mean that its name is unknowable; we can still try to find it by allowing the normal fall back on iterating through devices. An example scenario where this happens is with "/dev/console" in containers. It's a common practice among container managers to allocate a PTY master/slave pair in the host's mount namespace (the slave having a path like "/dev/pty/$X"), bind mount the slave to "/dev/console" in the container's mount namespace, and send the slave FD to a process in the container. Inside of the container, the slave-end isn't available at its original path ("/dev/pts/$X"), since the container mount namespace has a separate devpts instance from the host (that path may or may not exist in the container; if it does exist, it's not the same PTY slave device). Currently ttyname{_r} sees that the file at the original "/dev/pts/$X" path doesn't match the FD passed to it, and fails early and gives up, even though if it kept searching it would find the TTY at "/dev/console". Fix that; don't have the ENODEV path force an early return inhibiting the fall-back search. This change is based on the previous patch that adds use of is_mytty in getttyname and getttyname_r. Without that change, this effectively reverts 15e9a4f, which made us disregard the false similarity of file pointed to by "/proc/self/fd/$Y", because if it doesn't bail prematurely then that file ("/dev/pts/$X") will just come up again anyway in the fall-back search. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:36:44 +00:00
doispty = 1;
}
/* Prepare the result buffer. */
memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/"));
buflen -= sizeof ("/dev/pts/") - 1;
if (__xstat64 (_STAT_VER, buf, &st1) == 0 && S_ISDIR (st1.st_mode))
{
linux ttyname{_r}: Make tty checks consistent In the ttyname and ttyname_r routines on Linux, at several points it needs to check if a given TTY is the TTY we are looking for. It used to be that this check was (to see if `maybe` is `mytty`): __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #else && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev #endif This check appears in several places. Then, one of the changes made in commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 was to change that check to: __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #endif && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev That is, it made the st_ino and st_dev parts of the check happen even if we have the st_rdev member. This is an important change, because the kernel allows multiple devpts filesystem instances to be created; a device file in one devpts instance may share the same st_rdev with a file in another devpts instance, but they aren't the same file. This check appears twice in each file (ttyname.c and ttyname_r.c), once (in ttyname and __ttyname_r) to check if a candidate file found by inspecting /proc is the desired TTY, and once (in getttyname and getttyname_r) to check if a candidate file found by searching /dev is the desired TTY. However, 15e9a4f only updated the checks for files found via /proc; but the concern about collisions between devpts instances is just as valid for files found via /dev. So, update all 4 occurrences the check to be consistent with the version of the check introduced in 15e9a4f. Make it easy to keep all 4 occurrences of the check consistent by pulling it in to a static inline function, is_mytty. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:34:30 +00:00
ret = getttyname_r (buf, buflen, &st, save,
&dostat);
}
else
{
__set_errno (save);
ret = ENOENT;
}
if (ret && dostat != -1)
{
buf[sizeof ("/dev/") - 1] = '\0';
buflen += sizeof ("pts/") - 1;
linux ttyname{_r}: Make tty checks consistent In the ttyname and ttyname_r routines on Linux, at several points it needs to check if a given TTY is the TTY we are looking for. It used to be that this check was (to see if `maybe` is `mytty`): __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #else && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev #endif This check appears in several places. Then, one of the changes made in commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 was to change that check to: __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #endif && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev That is, it made the st_ino and st_dev parts of the check happen even if we have the st_rdev member. This is an important change, because the kernel allows multiple devpts filesystem instances to be created; a device file in one devpts instance may share the same st_rdev with a file in another devpts instance, but they aren't the same file. This check appears twice in each file (ttyname.c and ttyname_r.c), once (in ttyname and __ttyname_r) to check if a candidate file found by inspecting /proc is the desired TTY, and once (in getttyname and getttyname_r) to check if a candidate file found by searching /dev is the desired TTY. However, 15e9a4f only updated the checks for files found via /proc; but the concern about collisions between devpts instances is just as valid for files found via /dev. So, update all 4 occurrences the check to be consistent with the version of the check introduced in 15e9a4f. Make it easy to keep all 4 occurrences of the check consistent by pulling it in to a static inline function, is_mytty. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:34:30 +00:00
ret = getttyname_r (buf, buflen, &st, save,
&dostat);
}
if (ret && dostat != -1)
{
buf[sizeof ("/dev/") - 1] = '\0';
dostat = 1;
linux ttyname{_r}: Make tty checks consistent In the ttyname and ttyname_r routines on Linux, at several points it needs to check if a given TTY is the TTY we are looking for. It used to be that this check was (to see if `maybe` is `mytty`): __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #else && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev #endif This check appears in several places. Then, one of the changes made in commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 was to change that check to: __xstat64(_STAT_VER, maybe_filename, &maybe) == 0 #ifdef _STATBUF_ST_RDEV && S_ISCHR(maybe.st_mode) && maybe.st_rdev == mytty.st_rdev #endif && maybe.st_ino == mytty.st_ino && maybe.st_dev == mytty.st_dev That is, it made the st_ino and st_dev parts of the check happen even if we have the st_rdev member. This is an important change, because the kernel allows multiple devpts filesystem instances to be created; a device file in one devpts instance may share the same st_rdev with a file in another devpts instance, but they aren't the same file. This check appears twice in each file (ttyname.c and ttyname_r.c), once (in ttyname and __ttyname_r) to check if a candidate file found by inspecting /proc is the desired TTY, and once (in getttyname and getttyname_r) to check if a candidate file found by searching /dev is the desired TTY. However, 15e9a4f only updated the checks for files found via /proc; but the concern about collisions between devpts instances is just as valid for files found via /dev. So, update all 4 occurrences the check to be consistent with the version of the check introduced in 15e9a4f. Make it easy to keep all 4 occurrences of the check consistent by pulling it in to a static inline function, is_mytty. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:34:30 +00:00
ret = getttyname_r (buf, buflen, &st,
save, &dostat);
}
linux ttyname{_r}: Don't bail prematurely [BZ #22145] Commit 15e9a4f378c8607c2ae1aa465436af4321db0e23 introduced logic for ttyname() sending back ENODEV to signal that we can't get a name for the TTY because we inherited it from a different mount namespace. However, just because we inherited it from a different mount namespace and it isn't available at its original path, doesn't mean that its name is unknowable; we can still try to find it by allowing the normal fall back on iterating through devices. An example scenario where this happens is with "/dev/console" in containers. It's a common practice among container managers to allocate a PTY master/slave pair in the host's mount namespace (the slave having a path like "/dev/pty/$X"), bind mount the slave to "/dev/console" in the container's mount namespace, and send the slave FD to a process in the container. Inside of the container, the slave-end isn't available at its original path ("/dev/pts/$X"), since the container mount namespace has a separate devpts instance from the host (that path may or may not exist in the container; if it does exist, it's not the same PTY slave device). Currently ttyname{_r} sees that the file at the original "/dev/pts/$X" path doesn't match the FD passed to it, and fails early and gives up, even though if it kept searching it would find the TTY at "/dev/console". Fix that; don't have the ENODEV path force an early return inhibiting the fall-back search. This change is based on the previous patch that adds use of is_mytty in getttyname and getttyname_r. Without that change, this effectively reverts 15e9a4f, which made us disregard the false similarity of file pointed to by "/proc/self/fd/$Y", because if it doesn't bail prematurely then that file ("/dev/pts/$X") will just come up again anyway in the fall-back search. Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
2017-11-15 19:36:44 +00:00
if (ret && doispty && is_pty (&st))
{
/* We failed to figure out the TTY's name, but we can at least
signal that we did verify that it really is a PTY slave.
This happens when we have inherited the file descriptor from
a different mount namespace. */
__set_errno (ENODEV);
return ENODEV;
}
return ret;
}
weak_alias (__ttyname_r, ttyname_r)