idcache.c

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Hash : 26fd3545
Author :
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/idcache.c

/* idcache.c -- map user and group IDs, cached for speed

   Copyright (C) 1985, 1988-1990, 1997-1998, 2003, 2005-2007, 2009-2025 Free
   Software Foundation, Inc.

   This program 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 program 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/>.  */

#include <config.h>

#include "idcache.h"
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>

#include <unistd.h>

#include "flexmember.h"
#include "xalloc.h"

#ifdef __DJGPP__
static char digits[] = "0123456789";
#endif

struct userid
{
  union
    {
      uid_t u;
      gid_t g;
    } id;
  struct userid *next;
  char name[FLEXIBLE_ARRAY_MEMBER];
};

/* FIXME: provide a function to free any malloc'd storage and reset lists,
   so that an application can use code like this just before exiting:
   #if defined GCC_LINT || defined lint
     idcache_clear ();
   #endif
*/

static struct userid *user_alist;

/* Each entry on list is a user name for which the first lookup failed.  */
static struct userid *nouser_alist;

/* Use the same struct as for userids.  */
static struct userid *group_alist;

/* Each entry on list is a group name for which the first lookup failed.  */
static struct userid *nogroup_alist;

/* Translate UID to a login name, with cache, or NULL if unresolved.  */

char *
getuser (uid_t uid)
{
  struct userid *tail;
  struct userid *match = NULL;

  for (tail = user_alist; tail; tail = tail->next)
    {
      if (tail->id.u == uid)
        {
          match = tail;
          break;
        }
    }

  if (match == NULL)
    {
      struct passwd *pwent = getpwuid (uid);
      char const *name = pwent ? pwent->pw_name : "";
      match = xmalloc (FLEXSIZEOF (struct userid, name, strlen (name) + 1));
      match->id.u = uid;
      strcpy (match->name, name);

      /* Add to the head of the list, so most recently used is first.  */
      match->next = user_alist;
      user_alist = match;
    }

  return match->name[0] ? match->name : NULL;
}

/* Translate USER to a UID, with cache.
   Return NULL if there is no such user.
   (We also cache which user names have no passwd entry,
   so we don't keep looking them up.)  */

uid_t *
getuidbyname (const char *user)
{
  struct userid *tail;
  struct passwd *pwent;

  for (tail = user_alist; tail; tail = tail->next)
    /* Avoid a function call for the most common case.  */
    if (*tail->name == *user && streq (tail->name, user))
      return &tail->id.u;

  for (tail = nouser_alist; tail; tail = tail->next)
    /* Avoid a function call for the most common case.  */
    if (*tail->name == *user && streq (tail->name, user))
      return NULL;

  pwent = getpwnam (user);
#ifdef __DJGPP__
  /* We need to pretend to be the user USER, to make
     pwd functions know about an arbitrary user name.  */
  if (!pwent && strspn (user, digits) < strlen (user))
    {
      setenv ("USER", user, 1);
      pwent = getpwnam (user);  /* now it will succeed */
    }
#endif

  tail = xmalloc (FLEXSIZEOF (struct userid, name, strlen (user) + 1));
  strcpy (tail->name, user);

  /* Add to the head of the list, so most recently used is first.  */
  if (pwent)
    {
      tail->id.u = pwent->pw_uid;
      tail->next = user_alist;
      user_alist = tail;
      return &tail->id.u;
    }

  tail->next = nouser_alist;
  nouser_alist = tail;
  return NULL;
}

/* Translate GID to a group name, with cache, or NULL if unresolved.  */

char *
getgroup (gid_t gid)
{
  struct userid *tail;
  struct userid *match = NULL;

  for (tail = group_alist; tail; tail = tail->next)
    {
      if (tail->id.g == gid)
        {
          match = tail;
          break;
        }
    }

  if (match == NULL)
    {
      struct group *grent = getgrgid (gid);
      char const *name = grent ? grent->gr_name : "";
      match = xmalloc (FLEXSIZEOF (struct userid, name, strlen (name) + 1));
      match->id.g = gid;
      strcpy (match->name, name);

      /* Add to the head of the list, so most recently used is first.  */
      match->next = group_alist;
      group_alist = match;
    }

  return match->name[0] ? match->name : NULL;
}

/* Translate GROUP to a GID, with cache.
   Return NULL if there is no such group.
   (We also cache which group names have no group entry,
   so we don't keep looking them up.)  */

gid_t *
getgidbyname (const char *group)
{
  struct userid *tail;
  struct group *grent;

  for (tail = group_alist; tail; tail = tail->next)
    /* Avoid a function call for the most common case.  */
    if (*tail->name == *group && streq (tail->name, group))
      return &tail->id.g;

  for (tail = nogroup_alist; tail; tail = tail->next)
    /* Avoid a function call for the most common case.  */
    if (*tail->name == *group && streq (tail->name, group))
      return NULL;

  grent = getgrnam (group);
#ifdef __DJGPP__
  /* We need to pretend to belong to group GROUP, to make
     grp functions know about an arbitrary group name.  */
  if (!grent && strspn (group, digits) < strlen (group))
    {
      setenv ("GROUP", group, 1);
      grent = getgrnam (group); /* now it will succeed */
    }
#endif

  tail = xmalloc (FLEXSIZEOF (struct userid, name, strlen (group) + 1));
  strcpy (tail->name, group);

  /* Add to the head of the list, so most recently used is first.  */
  if (grent)
    {
      tail->id.g = grent->gr_gid;
      tail->next = group_alist;
      group_alist = tail;
      return &tail->id.g;
    }

  tail->next = nogroup_alist;
  nogroup_alist = tail;
  return NULL;
}

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kc3-lang/gnulib/lib/idcache.c

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lib/idcache.c