text: /* Test whether a file has a nontrivial access control list.
  
     Copyright (C) 2002-2003, 2005-2011 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 <http://www.gnu.org/licenses/>.
  
     Written by Paul Eggert, Andreas Grünbacher, and Bruno Haible.  */
  
  #include <config.h>
  
  #include "acl.h"
  
  #include "acl-internal.h"
  
  
  #if USE_ACL && HAVE_ACL_GET_FILE
  
  # if HAVE_ACL_TYPE_EXTENDED /* MacOS X */
  
  /* ACL is an ACL, from a file, stored as type ACL_TYPE_EXTENDED.
     Return 1 if the given ACL is non-trivial.
     Return 0 if it is trivial.  */
  int
  acl_extended_nontrivial (acl_t acl)
  {
    /* acl is non-trivial if it is non-empty.  */
    return (acl_entries (acl) > 0);
  }
  
  # else /* Linux, FreeBSD, IRIX, Tru64 */
  
  /* ACL is an ACL, from a file, stored as type ACL_TYPE_ACCESS.
     Return 1 if the given ACL is non-trivial.
     Return 0 if it is trivial, i.e. equivalent to a simple stat() mode.
     Return -1 and set errno upon failure to determine it.  */
  int
  acl_access_nontrivial (acl_t acl)
  {
    /* acl is non-trivial if it has some entries other than for "user::",
       "group::", and "other::".  Normally these three should be present
       at least, allowing us to write
          return (3 < acl_entries (acl));
       but the following code is more robust.  */
  #  if HAVE_ACL_FIRST_ENTRY /* Linux, FreeBSD */
  
    acl_entry_t ace;
    int got_one;
  
    for (got_one = acl_get_entry (acl, ACL_FIRST_ENTRY, &ace);
         got_one > 0;
         got_one = acl_get_entry (acl, ACL_NEXT_ENTRY, &ace))
      {
        acl_tag_t tag;
        if (acl_get_tag_type (ace, &tag) < 0)
          return -1;
        if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ || tag == ACL_OTHER))
          return 1;
      }
    return got_one;
  
  #  else /* IRIX, Tru64 */
  #   if HAVE_ACL_TO_SHORT_TEXT /* IRIX */
    /* Don't use acl_get_entry: it is undocumented.  */
  
    int count = acl->acl_cnt;
    int i;
  
    for (i = 0; i < count; i++)
      {
        acl_entry_t ace = &acl->acl_entry[i];
        acl_tag_t tag = ace->ae_tag;
  
        if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ
              || tag == ACL_OTHER_OBJ))
          return 1;
      }
    return 0;
  
  #   endif
  #   if HAVE_ACL_FREE_TEXT /* Tru64 */
    /* Don't use acl_get_entry: it takes only one argument and does not work.  */
  
    int count = acl->acl_num;
    acl_entry_t ace;
  
    for (ace = acl->acl_first; count > 0; ace = ace->next, count--)
      {
        acl_tag_t tag;
        acl_perm_t perm;
  
        tag = ace->entry->acl_type;
        if (!(tag == ACL_USER_OBJ || tag == ACL_GROUP_OBJ || tag == ACL_OTHER))
          return 1;
  
        perm = ace->entry->acl_perm;
        /* On Tru64, perm can also contain non-standard bits such as
           PERM_INSERT, PERM_DELETE, PERM_MODIFY, PERM_LOOKUP, ... */
        if ((perm & ~(ACL_READ | ACL_WRITE | ACL_EXECUTE)) != 0)
          return 1;
      }
    return 0;
  
  #   endif
  #  endif
  }
  
  # endif
  
  
  #elif USE_ACL && HAVE_FACL && defined GETACL /* Solaris, Cygwin, not HP-UX */
  
  # if !defined ACL_NO_TRIVIAL /* Solaris <= 10, Cygwin */
  
  /* Test an ACL retrieved with GETACL.
     Return 1 if the given ACL, consisting of COUNT entries, is non-trivial.
     Return 0 if it is trivial, i.e. equivalent to a simple stat() mode.  */
  int
  acl_nontrivial (int count, aclent_t *entries)
  {
    int i;
  
    for (i = 0; i < count; i++)
      {
        aclent_t *ace = &entries[i];
  
        /* Note: If ace->a_type = USER_OBJ, ace->a_id is the st_uid from stat().
           If ace->a_type = GROUP_OBJ, ace->a_id is the st_gid from stat().
           We don't need to check ace->a_id in these cases.  */
        if (!(ace->a_type == USER_OBJ
              || ace->a_type == GROUP_OBJ
              || ace->a_type == OTHER_OBJ
              /* Note: Cygwin does not return a CLASS_OBJ ("mask:") entry
                 sometimes.  */
              || ace->a_type == CLASS_OBJ))
          return 1;
      }
    return 0;
  }
  
  #  ifdef ACE_GETACL
  
  /* Test an ACL retrieved with ACE_GETACL.
     Return 1 if the given ACL, consisting of COUNT entries, is non-trivial.
     Return 0 if it is trivial, i.e. equivalent to a simple stat() mode.  */
  int
  acl_ace_nontrivial (int count, ace_t *entries)
  {
    int i;
  
    /* The flags in the ace_t structure changed in a binary incompatible way
       when ACL_NO_TRIVIAL etc. were introduced in <sys/acl.h> version 1.15.
       How to distinguish the two conventions at runtime?
       In the old convention, usually three ACEs have a_flags = ACE_OWNER /
       ACE_GROUP / ACE_OTHER, in the range 0x0100..0x0400.  In the new
       convention, these values are not used.  */
    int old_convention = 0;
  
    for (i = 0; i < count; i++)
      if (entries[i].a_flags & (ACE_OWNER | ACE_GROUP | ACE_OTHER))
        {
          old_convention = 1;
          break;
        }
  
    if (old_convention)
      /* Running on Solaris 10.  */
      for (i = 0; i < count; i++)
        {
          ace_t *ace = &entries[i];
  
          /* Note:
             If ace->a_flags = ACE_OWNER, ace->a_who is the st_uid from stat().
             If ace->a_flags = ACE_GROUP, ace->a_who is the st_gid from stat().
             We don't need to check ace->a_who in these cases.  */
          if (!(ace->a_type == ALLOW
                && (ace->a_flags == ACE_OWNER
                    || ace->a_flags == ACE_GROUP
                    || ace->a_flags == ACE_OTHER)))
            return 1;
        }
    else
      /* Running on Solaris 10 (newer version) or Solaris 11.  */
      for (i = 0; i < count; i++)
        {
          ace_t *ace = &entries[i];
  
          if (!(ace->a_type == ACE_ACCESS_ALLOWED_ACE_TYPE
                && (ace->a_flags == NEW_ACE_OWNER
                    || ace->a_flags
                       == (NEW_ACE_GROUP | NEW_ACE_IDENTIFIER_GROUP)
                    || ace->a_flags == ACE_EVERYONE)
                && (ace->a_access_mask
                    & ~(NEW_ACE_READ_DATA | NEW_ACE_WRITE_DATA | NEW_ACE_EXECUTE))
                   == 0))
            return 1;
        }
  
    return 0;
  }
  
  #  endif
  
  # endif
  
  #elif USE_ACL && HAVE_GETACL /* HP-UX */
  
  /* Return 1 if the given ACL is non-trivial.
     Return 0 if it is trivial, i.e. equivalent to a simple stat() mode.  */
  int
  acl_nontrivial (int count, struct acl_entry *entries, struct stat *sb)
  {
    int i;
  
    for (i = 0; i < count; i++)
      {
        struct acl_entry *ace = &entries[i];
  
        if (!((ace->uid == sb->st_uid && ace->gid == ACL_NSGROUP)
              || (ace->uid == ACL_NSUSER && ace->gid == sb->st_gid)
              || (ace->uid == ACL_NSUSER && ace->gid == ACL_NSGROUP)))
          return 1;
      }
    return 0;
  }
  
  #elif USE_ACL && (HAVE_ACLX_GET || HAVE_STATACL) /* AIX */
  
  /* Return 1 if the given ACL is non-trivial.
     Return 0 if it is trivial, i.e. equivalent to a simple stat() mode.  */
  int
  acl_nontrivial (struct acl *a)
  {
    /* The normal way to iterate through an ACL is like this:
         struct acl_entry *ace;
         for (ace = a->acl_ext; ace != acl_last (a); ace = acl_nxt (ace))
           {
             struct ace_id *aei;
             switch (ace->ace_type)
               {
               case ACC_PERMIT:
               case ACC_DENY:
               case ACC_SPECIFY:
                 ...;
               }
             for (aei = ace->ace_id; aei != id_last (ace); aei = id_nxt (aei))
               ...
           }
     */
    return (acl_last (a) != a->acl_ext ? 1 : 0);
  }
  
  # if HAVE_ACLX_GET && defined ACL_AIX_WIP /* newer AIX */
  
  /* Return 1 if the given ACL is non-trivial.
     Return 0 if it is trivial, i.e. equivalent to a simple stat() mode.  */
  int
  acl_nfs4_nontrivial (nfs4_acl_int_t *a)
  {
  #  if 1 /* let's try this first */
    return (a->aclEntryN > 0 ? 1 : 0);
  #  else
    int count = a->aclEntryN;
    int i;
  
    for (i = 0; i < count; i++)
      {
        nfs4_ace_int_t *ace = &a->aclEntry[i];
  
        if (!((ace->flags & ACE4_ID_SPECIAL) != 0
              && (ace->aceWho.special_whoid == ACE4_WHO_OWNER
                  || ace->aceWho.special_whoid == ACE4_WHO_GROUP
                  || ace->aceWho.special_whoid == ACE4_WHO_EVERYONE)
              && ace->aceType == ACE4_ACCESS_ALLOWED_ACE_TYPE
              && ace->aceFlags == 0
              && (ace->aceMask & ~(ACE4_READ_DATA | ACE4_LIST_DIRECTORY
                                   | ACE4_WRITE_DATA | ACE4_ADD_FILE
                                   | ACE4_EXECUTE)) == 0))
          return 1;
      }
    return 0;
  #  endif
  }
  
  # endif
  
  #elif USE_ACL && HAVE_ACLSORT /* NonStop Kernel */
  
  /* Test an ACL retrieved with ACL_GET.
     Return 1 if the given ACL, consisting of COUNT entries, is non-trivial.
     Return 0 if it is trivial, i.e. equivalent to a simple stat() mode.  */
  int
  acl_nontrivial (int count, struct acl *entries)
  {
    int i;
  
    for (i = 0; i < count; i++)
      {
        struct acl *ace = &entries[i];
  
        /* Note: If ace->a_type = USER_OBJ, ace->a_id is the st_uid from stat().
           If ace->a_type = GROUP_OBJ, ace->a_id is the st_gid from stat().
           We don't need to check ace->a_id in these cases.  */
        if (!(ace->a_type == USER_OBJ /* no need to check ace->a_id here */
              || ace->a_type == GROUP_OBJ /* no need to check ace->a_id here */
              || ace->a_type == CLASS_OBJ
              || ace->a_type == OTHER_OBJ))
          return 1;
      }
    return 0;
  }
  
  #endif
  
  
  /* Return 1 if NAME has a nontrivial access control list, 0 if NAME
     only has no or a base access control list, and -1 (setting errno)
     on error.  SB must be set to the stat buffer of FILE.  */
  
  int
  file_has_acl (char const *name, struct stat const *sb)
  {
  #if USE_ACL
    if (! S_ISLNK (sb->st_mode))
      {
  # if HAVE_ACL_GET_FILE
  
        /* POSIX 1003.1e (draft 17 -- abandoned) specific version.  */
        /* Linux, FreeBSD, MacOS X, IRIX, Tru64 */
        int ret;
  
        if (HAVE_ACL_EXTENDED_FILE) /* Linux */
          {
            /* On Linux, acl_extended_file is an optimized function: It only
               makes two calls to getxattr(), one for ACL_TYPE_ACCESS, one for
               ACL_TYPE_DEFAULT.  */
            ret = acl_extended_file (name);
          }
        else /* FreeBSD, MacOS X, IRIX, Tru64 */
          {
  #  if HAVE_ACL_TYPE_EXTENDED /* MacOS X */
            /* On MacOS X, acl_get_file (name, ACL_TYPE_ACCESS)
               and acl_get_file (name, ACL_TYPE_DEFAULT)
               always return NULL / EINVAL.  There is no point in making
               these two useless calls.  The real ACL is retrieved through
               acl_get_file (name, ACL_TYPE_EXTENDED).  */
            acl_t acl = acl_get_file (name, ACL_TYPE_EXTENDED);
            if (acl)
              {
                ret = acl_extended_nontrivial (acl);
                acl_free (acl);
              }
            else
              ret = -1;
  #  else /* FreeBSD, IRIX, Tru64 */
            acl_t acl = acl_get_file (name, ACL_TYPE_ACCESS);
            if (acl)
              {
                int saved_errno;
  
                ret = acl_access_nontrivial (acl);
                saved_errno = errno;
                acl_free (acl);
                errno = saved_errno;
  #   if HAVE_ACL_FREE_TEXT /* Tru64 */
                /* On OSF/1, acl_get_file (name, ACL_TYPE_DEFAULT) always
                   returns NULL with errno not set.  There is no point in
                   making this call.  */
  #   else /* FreeBSD, IRIX */
                /* On Linux, FreeBSD, IRIX, acl_get_file (name, ACL_TYPE_ACCESS)
                   and acl_get_file (name, ACL_TYPE_DEFAULT) on a directory
                   either both succeed or both fail; it depends on the
                   file system.  Therefore there is no point in making the second
                   call if the first one already failed.  */
                if (ret == 0 && S_ISDIR (sb->st_mode))
                  {
                    acl = acl_get_file (name, ACL_TYPE_DEFAULT);
                    if (acl)
                      {
                        ret = (0 < acl_entries (acl));
                        acl_free (acl);
                      }
                    else
                      ret = -1;
                  }
  #   endif
              }
            else
              ret = -1;
  #  endif
          }
        if (ret < 0)
          return ACL_NOT_WELL_SUPPORTED (errno) ? 0 : -1;
        return ret;
  
  # elif HAVE_FACL && defined GETACLCNT /* Solaris, Cygwin, not HP-UX */
  
  #  if defined ACL_NO_TRIVIAL
  
        /* Solaris 10 (newer version), which has additional API declared in
           <sys/acl.h> (acl_t) and implemented in libsec (acl_set, acl_trivial,
           acl_fromtext, ...).  */
        return acl_trivial (name);
  
  #  else /* Solaris, Cygwin, general case */
  
        /* Solaris 2.5 through Solaris 10, Cygwin, and contemporaneous versions
           of Unixware.  The acl() call returns the access and default ACL both
           at once.  */
        int count;
        {
          aclent_t *entries;
  
          for (;;)
            {
              count = acl (name, GETACLCNT, 0, NULL);
  
              if (count < 0)
                {
                  if (errno == ENOSYS || errno == ENOTSUP)
                    break;
                  else
                    return -1;
                }
  
              if (count == 0)
                break;
  
              /* Don't use MIN_ACL_ENTRIES:  It's set to 4 on Cygwin, but Cygwin
                 returns only 3 entries for files with no ACL.  But this is safe:
                 If there are more than 4 entries, there cannot be only the
                 "user::", "group::", "other:", and "mask:" entries.  */
              if (count > 4)
                return 1;
  
              entries = (aclent_t *) malloc (count * sizeof (aclent_t));
              if (entries == NULL)
                {
                  errno = ENOMEM;
                  return -1;
                }
              if (acl (name, GETACL, count, entries) == count)
                {
                  if (acl_nontrivial (count, entries))
                    {
                      free (entries);
                      return 1;
                    }
                  free (entries);
                  break;
                }
              /* Huh? The number of ACL entries changed since the last call.
                 Repeat.  */
              free (entries);
            }
        }
  
  #   ifdef ACE_GETACL
        /* Solaris also has a different variant of ACLs, used in ZFS and NFSv4
           file systems (whereas the other ones are used in UFS file systems).  */
        {
          ace_t *entries;
  
          for (;;)
            {
              count = acl (name, ACE_GETACLCNT, 0, NULL);
  
              if (count < 0)
                {
                  if (errno == ENOSYS || errno == EINVAL)
                    break;
                  else
                    return -1;
                }
  
              if (count == 0)
                break;
  
              /* If there are more than 3 entries, there cannot be only the
                 ACE_OWNER, ACE_GROUP, ACE_OTHER entries.  */
              if (count > 3)
                return 1;
  
              entries = (ace_t *) malloc (count * sizeof (ace_t));
              if (entries == NULL)
                {
                  errno = ENOMEM;
                  return -1;
                }
              if (acl (name, ACE_GETACL, count, entries) == count)
                {
                  if (acl_ace_nontrivial (count, entries))
                    {
                      free (entries);
                      return 1;
                    }
                  free (entries);
                  break;
                }
              /* Huh? The number of ACL entries changed since the last call.
                 Repeat.  */
              free (entries);
            }
        }
  #   endif
  
        return 0;
  #  endif
  
  # elif HAVE_GETACL /* HP-UX */
  
        int count;
        struct acl_entry entries[NACLENTRIES];
  
        for (;;)
          {
            count = getacl (name, 0, NULL);
  
            if (count < 0)
              return (errno == ENOSYS || errno == EOPNOTSUPP ? 0 : -1);
  
            if (count == 0)
              return 0;
  
            if (count > NACLENTRIES)
              /* If NACLENTRIES cannot be trusted, use dynamic memory
                 allocation.  */
              abort ();
  
            /* If there are more than 3 entries, there cannot be only the
               (uid,%), (%,gid), (%,%) entries.  */
            if (count > 3)
              return 1;
  
            if (getacl (name, count, entries) == count)
              {
                struct stat statbuf;
  
                if (stat (name, &statbuf) < 0)
                  return -1;
  
                return acl_nontrivial (count, entries, &statbuf);
              }
            /* Huh? The number of ACL entries changed since the last call.
               Repeat.  */
          }
  
  # elif HAVE_ACLX_GET && defined ACL_AIX_WIP /* AIX */
  
        acl_type_t type;
        char aclbuf[1024];
        void *acl = aclbuf;
        size_t aclsize = sizeof (aclbuf);
        mode_t mode;
  
        for (;;)
          {
            /* The docs say that type being 0 is equivalent to ACL_ANY, but it
               is not true, in AIX 5.3.  */
            type.u64 = ACL_ANY;
            if (aclx_get (name, 0, &type, aclbuf, &aclsize, &mode) >= 0)
              break;
            if (errno != ENOSPC)
              {
                if (acl != aclbuf)
                  {
                    int saved_errno = errno;
                    free (acl);
                    errno = saved_errno;
                  }
                return -1;
              }
            aclsize = 2 * aclsize;
            if (acl != aclbuf)
              free (acl);
            acl = malloc (aclsize);
            if (acl == NULL)
              {
                errno = ENOMEM;
                return -1;
              }
          }
  
        if (type.u64 == ACL_AIXC)
          {
            int result = acl_nontrivial ((struct acl *) acl);
            if (acl != aclbuf)
              free (acl);
            return result;
          }
        else if (type.u64 == ACL_NFS4)
          {
            int result = acl_nfs4_nontrivial ((nfs4_acl_int_t *) acl);
            if (acl != aclbuf)
              free (acl);
            return result;
          }
        else
          {
            /* A newer type of ACL has been introduced in the system.
               We should better support it.  */
            if (acl != aclbuf)
              free (acl);
            errno = EINVAL;
            return -1;
          }
  
  # elif HAVE_STATACL /* older AIX */
  
        union { struct acl a; char room[4096]; } u;
  
        if (statacl (name, STX_NORMAL, &u.a, sizeof (u)) < 0)
          return -1;
  
        return acl_nontrivial (&u.a);
  
  # elif HAVE_ACLSORT /* NonStop Kernel */
  
        int count;
        struct acl entries[NACLENTRIES];
  
        for (;;)
          {
            count = acl ((char *) name, ACL_CNT, NACLENTRIES, NULL);
  
            if (count < 0)
              return -1;
  
            if (count == 0)
              return 0;
  
            if (count > NACLENTRIES)
              /* If NACLENTRIES cannot be trusted, use dynamic memory
                 allocation.  */
              abort ();
  
            /* If there are more than 4 entries, there cannot be only the
               four base ACL entries.  */
            if (count > 4)
              return 1;
  
            if (acl ((char *) name, ACL_GET, count, entries) == count)
              return acl_nontrivial (count, entries);
            /* Huh? The number of ACL entries changed since the last call.
               Repeat.  */
          }
  
  # endif
      }
  #endif
  
    return 0;
  }
  