getlogin.c

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Hash : 26fd3545
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Date : 2025-09-16T23:08:01

stringeq: prefer streq to strcmp in other modules

* lib/acl-internal.c, lib/argmatch.c, lib/argp-help.c:
* lib/argp-parse.c, lib/bcp47.c, lib/c32_get_mapping.c:
* lib/c32_get_type_test.c, lib/concat-filename.c:
* lib/cpu-supports.h, lib/dfa.c, lib/duplocale.c, lib/exclude.c:
* lib/findprog-in.c, lib/findprog.c, lib/fopen.c, lib/freopen.c:
* lib/fts.c, lib/gen-uni-tables.c, lib/getfilecon.c:
* lib/getlogin.c, lib/getugroups.c, lib/hard-locale.c:
* lib/hashcode-named-file.c, lib/hashkey-string.c:
* lib/iconv_open.c, lib/idcache.c, lib/lc-charset-unicode.c:
* lib/localcharset.c, lib/localename-environ.c:
* lib/localename-unsafe.c, lib/mbs_endswith.c, lib/mountlist.c:
* lib/newlocale.c, lib/nl_langinfo.c, lib/nproc.c, lib/open.c:
* lib/os2-spawn.c, lib/parse-datetime.y, lib/popen.c:
* lib/progreloc.c, lib/propername.c, lib/pt_chown.c, lib/putenv.c:
* lib/qcopy-acl.c, lib/readutmp.c, lib/rpmatch.c:
* lib/setlocale-fixes.c, lib/setlocale.c, lib/sig2str.c:
* lib/spawni.c, lib/stat.c, lib/str_endswith.c, lib/streq.h:
* lib/striconveha.c, lib/struniq.h, lib/supersede.c:
* lib/time_rz.c, lib/unicodeio.c, lib/vasnprintf.c:
* lib/vc-mtime.c, lib/wctrans-impl.h, lib/wctype-impl.h:
Prefer streq to strcmp when either will do.
Do not make this change to files shared with glibc.
Do not make the change to test files, at least not for now.
* lib/gen-uni-tables.c (streq): New static function, in same style.
* modules/acl-permissions, modules/argp, modules/c32_get_mapping:
* modules/c32_get_type_test, modules/concat-filename:
* modules/cpu-supports, modules/dfa, modules/duplocale:
* modules/exclude, modules/findprog, modules/findprog-in:
* modules/fopen, modules/fopen-gnu, modules/freopen, modules/fts:
* modules/getlocalename_l-simple, modules/getlocalename_l-unsafe:
* modules/getlogin, modules/getugroups, modules/hard-locale:
* modules/hashcode-named-file, modules/hashkey-string:
* modules/iconv_open, modules/idcache, modules/localcharset:
* modules/localename, modules/localename-unsafe:
* modules/mbs_endswith, modules/mountlist, modules/newlocale:
* modules/nl_langinfo, modules/nproc, modules/open:
* modules/parse-datetime, modules/popen:
* modules/posix_spawn-internal, modules/propername:
* modules/pt_chown, modules/putenv-gnu, modules/qcopy-acl:
* modules/rpmatch, modules/selinux-h, modules/setenv:
* modules/setlocale, modules/setlocale-fixes, modules/sig2str:
* modules/spawn-pipe, modules/stat, modules/str_endswith:
* modules/streq, modules/striconveha, modules/supersede:
* modules/time_rz, modules/uchar-h, modules/unicodeio:
* modules/uniconv/base, modules/wctrans, modules/wctype:
(Depends-on): Add stringeq.

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lib/getlogin.c

/* Provide a working getlogin for systems which lack it.

   Copyright (C) 2010-2025 Free Software Foundation, Inc.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published
   by the Free Software Foundation, either version 3 of the License,
   or (at your option) any later version.

   This file 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible, 2010, 2025.  */

#include <config.h>

/* Specification.  */
#include <unistd.h>

#if defined _WIN32 && ! defined __CYGWIN__
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
/* Don't assume that UNICODE is not defined.  */
# undef GetUserName
# define GetUserName GetUserNameA
#endif

#if defined __linux__ || defined __ANDROID__
# include <fcntl.h>
# include <pwd.h>
# include <stdlib.h>
# include <string.h>
# include <sys/stat.h>
# include "readutmp.h"
#endif

char *
getlogin (void)
{
#if defined _WIN32 && ! defined __CYGWIN__
  /* Native Windows platform.  */
  static char login_name[1024];
  DWORD sz = sizeof (login_name);

  if (GetUserName (login_name, &sz))
    return login_name;
#elif defined __linux__ || defined __ANDROID__
  /* Linux.  */
  {
    /* Read the login uid from the /proc file system.  */
    int fd = open ("/proc/self/loginuid", O_RDONLY);
    if (fd >= 0)
      {
        char buf[20 + 1];
        int n = read (fd, buf, sizeof (buf) - 1);
        if (n > 0)
          {
            buf[n] = '\0';
            char *endptr;
            unsigned long uid = strtoul (buf, &endptr, 10);
            if (endptr == buf + n && uid != (uid_t) -1)
              {
                /* Convert the uid to a user name.  */
                struct passwd *p = getpwuid (uid);
                if (p != NULL && strlen (p->pw_name) < 64)
                  {
                    static char resultbuf[64];
                    strcpy (resultbuf, p->pw_name);
                    close (fd);
                    return resultbuf;
                  }
              }
          }
        close (fd);
      }
  }
  {
    /* Find the tty connected to the current process.  */
    char *tty = ttyname (STDIN_FILENO);
    if (tty != NULL)
      {
        /* Try to see to which user it is allocated, via utmp.  */
        if (strncmp (tty, "/dev/tty", 8) == 0)
          {
            idx_t n;
            STRUCT_UTMP *entries;
            if (read_utmp (UTMP_FILE, &n, &entries, READ_UTMP_USER_PROCESS)
                == 0)
              {
                idx_t i;
                for (i = 0; i < n; i++)
                  if (streq (entries[i].ut_line, tty + 5))
                    {
                      if (strlen (entries[i].ut_user) < 64)
                        {
                          static char resultbuf[64];
                          strcpy (resultbuf, entries[i].ut_user);
                          free (entries);
                          return resultbuf;
                        }
                      break;
                    }
                free (entries);
              }
          }
        /* Fallback for systems which don't maintain an utmp database
           or for ttys that are not recorded in that the utmp database:
           Look at the owner of that tty.  */
        struct stat statbuf;
        if (stat (tty, &statbuf) >= 0)
          {
            uid_t uid = statbuf.st_uid;
            /* Convert the uid to a user name.  */
            struct passwd *p = getpwuid (uid);
            if (p != NULL && strlen (p->pw_name) < 64)
              {
                static char resultbuf[64];
                strcpy (resultbuf, p->pw_name);
                return resultbuf;
              }
          }
      }
  }
#endif
  return NULL;
}

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kc3-lang/gnulib/lib/getlogin.c

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lib/getlogin.c