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123 lines
3.1 KiB
C
123 lines
3.1 KiB
C
/* Copyright (C) 2010-2015 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, see
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<http://www.gnu.org/licenses/>. */
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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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/* Try to determine login name from /proc/self/loginuid and return 0
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if successful. If /proc/self/loginuid cannot be read return -1.
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Otherwise return the error number. */
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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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/* We are reading a 32-bit number. 12 bytes are enough for the text
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representation. If not, something is wrong. */
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char uidbuf[12];
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ssize_t n = TEMP_FAILURE_RETRY (read_not_cancel (fd, uidbuf,
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sizeof (uidbuf)));
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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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|| n == sizeof (uidbuf)
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|| (uidbuf[n] = '\0',
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uid = strtoul (uidbuf, &endp, 10),
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endp == uidbuf || *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 result = 0;
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int res;
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while ((res = __getpwuid_r (uid, &pwd, buf, buflen, &tpwd)) == ERANGE)
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if (__libc_use_alloca (2 * buflen))
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buf = 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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result = ENOMEM;
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goto out;
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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 (res != 0 || tpwd == NULL)
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{
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result = -1;
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goto out;
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}
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size_t needed = strlen (pwd.pw_name) + 1;
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if (needed > namesize)
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{
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__set_errno (ERANGE);
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result = ERANGE;
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goto out;
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}
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memcpy (name, pwd.pw_name, needed);
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out:
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if (use_malloc)
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free (buf);
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return result;
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}
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/* Return at most NAME_LEN characters of the login name of the user in NAME.
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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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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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int res = __getlogin_r_loginuid (name, namesize);
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if (res >= 0)
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return res;
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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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