Fix Linux getlogin{_r,} implementation
The old implementation uses fd 0 to determine the login TTY. This was needed because using /dev/tty it is not possible to deduce the login TTY. For some time now there is the pseudo-file /proc/self/loginuid which directly helps us to find the user. Prefer using this file. It also works if stdin is closed, redirected, or re-opened.
This commit is contained in:
Ulrich Drepper
parent
fd8ccb0427
commit
c8727fa6e5
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@ -1,5 +1,12 @@
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2010-03-24 Ulrich Drepper <drepper@redhat.com>
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* sysdeps/unix/sysv/linux/getlogin_r.c: New file.
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* sysdeps/unix/sysv/linux/getlogin.c: New file.
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* sysdeps/unix/getlogin_r.c: Allow compiling getlogin as static
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function.
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* sysdeps/unix/getlogin.c: Likewise. Move name variable to toplevel.
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* include/unistd.h: Declare __getlogin_r_loginuid.
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[BZ #11397]
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* sysdeps/posix/cuserid.c (cuserid): Make sure the returned string
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is NUL terminated.
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@ -176,6 +176,9 @@ extern int __have_sock_cloexec;
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unless it is really necessary. */
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#define __have_pipe2 __have_sock_cloexec
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extern int __getlogin_r_loginuid (char *name, size_t namesize)
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attribute_hidden;
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__END_DECLS
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#endif
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@ -1,4 +1,4 @@
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/* Copyright (C) 1991, 1992, 1996, 1997 Free Software Foundation, Inc.
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/* Copyright (C) 1991, 1992, 1996, 1997, 2010 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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@ -25,16 +25,20 @@
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#include <utmp.h>
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static char name[UT_NAMESIZE + 1];
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/* Return the login name of the user, or NULL if it can't be determined.
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The returned pointer, if not NULL, is good only until the next call. */
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#ifdef STATIC
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STATIC
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#endif
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char *
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getlogin (void)
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{
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char tty_pathname[2 + 2 * NAME_MAX];
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char *real_tty_path = tty_pathname;
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char *result = NULL;
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static char name[UT_NAMESIZE + 1];
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struct utmp *ut, line, buffer;
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/* Get name of tty connected to fd 0. Return NULL if not a tty or
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@ -1,5 +1,5 @@
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/* Reentrant function to return the current login name. Unix version.
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Copyright (C) 1991,92,96,97,98,2002 Free Software Foundation, Inc.
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Copyright (C) 1991,92,96,97,98,2002,2010 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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@ -31,6 +31,9 @@
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If it cannot be determined or some other error occurred, return the error
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code. Otherwise return 0. */
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#ifdef STATIC
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STATIC
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#endif
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int
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getlogin_r (name, name_len)
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char *name;
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@ -96,4 +99,6 @@ getlogin_r (name, name_len)
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return result;
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}
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#ifndef STATIC
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libc_hidden_def (getlogin_r)
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#endif
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@ -0,0 +1,39 @@
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/* Copyright (C) 2010 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <pwd.h>
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#include <unistd.h>
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#include <not-cancel.h>
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#define STATIC static
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#define getlogin getlogin_fd0
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#include <sysdeps/unix/getlogin.c>
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#undef getlogin
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/* Return the login name of the user, or NULL if it can't be determined.
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The returned pointer, if not NULL, is good only until the next call. */
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char *
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getlogin (void)
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{
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if (__getlogin_r_loginuid (name, sizeof (name)) == 0)
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return name;
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return getlogin_fd0 ();
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}
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@ -0,0 +1,100 @@
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/* Copyright (C) 2010 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <pwd.h>
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#include <unistd.h>
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#include <not-cancel.h>
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#define STATIC static
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static int getlogin_r_fd0 (char *name, size_t namesize);
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#define getlogin_r getlogin_r_fd0
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#include <sysdeps/unix/getlogin_r.c>
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#undef getlogin_r
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int
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attribute_hidden
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__getlogin_r_loginuid (name, namesize)
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char *name;
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size_t namesize;
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{
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int fd = open_not_cancel_2 ("/proc/self/loginuid", O_RDONLY);
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if (fd == -1)
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return 1;
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ssize_t n = TEMP_FAILURE_RETRY (read_not_cancel (fd, name, namesize));
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close_not_cancel_no_status (fd);
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uid_t uid;
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char *endp;
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if (n <= 0
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|| (uid = strtoul (name, &endp, 10), endp == name || *endp != '\0'))
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return 1;
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size_t buflen = 1024;
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char *buf = alloca (buflen);
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bool use_malloc = false;
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struct passwd pwd;
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struct passwd *tpwd;
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int res;
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while ((res = __getpwuid_r (uid, &pwd, buf, buflen, &tpwd)) != 0)
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if (__libc_use_alloca (2 * buflen))
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extend_alloca (buf, buflen, 2 * buflen);
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else
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{
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buflen *= 2;
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char *newp = realloc (use_malloc ? buf : NULL, buflen);
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if (newp == NULL)
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{
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fail:
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if (use_malloc)
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free (buf);
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return 1;
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}
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buf = newp;
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use_malloc = true;
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}
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if (tpwd == NULL)
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goto fail;
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strncpy (name, pwd.pw_name, namesize - 1);
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name[namesize - 1] = '\0';
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if (use_malloc)
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free (buf);
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return 0;
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}
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/* Return the login name of the user, or NULL if it can't be determined.
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The returned pointer, if not NULL, is good only until the next call. */
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int
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getlogin_r (name, namesize)
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char *name;
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size_t namesize;
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{
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if (__getlogin_r_loginuid (name, namesize) == 0)
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return 0;
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return getlogin_r_fd0 (name, namesize);
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}
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libc_hidden_def (getlogin_r)
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