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 /* High-level libcrypt interfaces.
 
    Copyright (C) 1991-2017 Free Software Foundation, Inc.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public License
    as published by the Free Software Foundation; either version 2.1 of
    the License, or (at your option) any later version.
 
    This library 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 Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
 #ifndef _CRYPT_H
 #define _CRYPT_H 1
 
 #include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
 /* The strings returned by crypt, crypt_r, crypt_rn, and crypt_ra will
    be no longer than this, counting the terminating NUL.  (Existing
    algorithms all produce much shorter strings, but we have reserved
    generous space for future expansion.)  This is NOT the appropriate
    size to use in allocating the buffer supplied to crypt_rn; use
    sizeof (struct crypt_data) instead.  */
 #define CRYPT_OUTPUT_SIZE 384
 
 /* Passphrases longer than this (counting the terminating NUL) are not
    supported.  Note that some hash algorithms have lower limits.  */
 #define CRYPT_MAX_PASSPHRASE_SIZE 512
 
 /* The strings returned by crypt_gensalt, crypt_gensalt_rn, and
    crypt_gensalt_ra will be no longer than this.  This IS the
    appropriate size to use when allocating the buffer supplied to
    crypt_gensalt_rn.  (Again, existing algorithms all produce
    much shorter strings, but we have reserved generous space for
    future expansion.)  */
 #define CRYPT_GENSALT_OUTPUT_SIZE 192
 
 /* One-way hash the passphrase PHRASE as specified by SETTING, and
    return a string suitable for storage in a Unix-style "passwd" file.
 
    If SETTING is a previously hashed passphrase, the string returned
    will be equal to SETTING if and only if PHRASE is the same as the
    passphrase that was previously hashed.  See the documentation for
    other ways to use this function.
 
    The string returned by this function is stored in a statically-
    allocated buffer, and will be overwritten if the function is called
    again.  It is not safe to call this function from multiple threads
    concurrently.
 
    If an error occurs (such as SETTING being nonsense or unsupported)
    the string returned will begin with '*', and will not be equal to
    SETTING nor to any valid hashed passphrase.  Otherwise, the string
    will not begin with '*'.  */
 extern char *crypt (const char *__phrase, const char *__setting)
 __THROW;
 
 /* These sizes are chosen to make sizeof (struct crypt_data) add up to
    exactly 32768 bytes.  */
 #define CRYPT_DATA_RESERVED_SIZE 767
 #define CRYPT_DATA_INTERNAL_SIZE 30720
 
 /* Memory area used by crypt_r.  */
 struct crypt_data
 {
   /* crypt_r writes the hashed password to this field of its 'data'
      argument.  crypt_rn and crypt_ra do the same, treating the
      untyped data area they are supplied with as this struct.  */
   char output[CRYPT_OUTPUT_SIZE];
 
   /* Applications are encouraged, but not required, to use this field
      to store the "setting" string that must be passed to crypt_*.
      Future extensions to the API may make this more ergonomic.
 
      A valid "setting" is either previously hashed password or the
      string produced by one of the crypt_gensalt functions; see the
      crypt_gensalt documentation for further details.  */
   char setting[CRYPT_OUTPUT_SIZE];
 
   /* Applications are encouraged, but not required, to use this field
      to store the unhashed passphrase they will pass to crypt_*.
      Future extensions to the API may make this more ergonomic.  */
   char input[CRYPT_MAX_PASSPHRASE_SIZE];
 
   /* Reserved for future application-visible fields.  For maximum
      forward compatibility, applications should set this field to all
      bytes zero before calling crypt_r, crypt_rn, or crypt_ra for the
      first time with a just-allocated 'struct crypt_data'.  Future
      extensions to the API may make this more ergonomic.  */
   char reserved[CRYPT_DATA_RESERVED_SIZE];
 
   /* This field should be set to 0 before calling crypt_r, crypt_rn,
      or crypt_ra for the first time with a just-allocated
      'struct crypt_data'.  This is not required if crypt_ra is allowed
      to do the allocation itself (i.e. if the *DATA argument is a null
      pointer).  Future extensions to the API may make this more ergonomic.  */
   char initialized;
 
   /* Scratch space used internally.  Applications should not read or
      write this field.  All data written to this area is erased before
      returning from the library.  */
   char internal[CRYPT_DATA_INTERNAL_SIZE];
 };
 
 /* Thread-safe version of crypt.  Instead of writing to a static
    storage area, the string returned by this function will be within
    DATA->output.  Otherwise, behaves exactly the same as crypt.  */
 extern char *crypt_r (const char *__phrase, const char *__setting,
                       struct crypt_data *__restrict __data)
 __THROW;
 
 /* Another thread-safe version of crypt.  Instead of writing to a
    static storage area, the string returned by this function will be
    somewhere within the space provided at DATA, which is of length SIZE
    bytes.  SIZE must be at least sizeof (struct crypt_data).
 
    Also, if an error occurs, this function returns a null pointer,
    not a special string.  (However, the string returned on success
    still will never begin with '*'.)  */
 extern char *crypt_rn (const char *__phrase, const char *__setting,
                        void *__data, int __size)
 __THROW;
 
 /* Yet a third thread-safe version of crypt; this one works like
    getline(3).  *DATA must be either 0 or a pointer to memory
    allocated by malloc, and *SIZE must be the size of the allocation.
    This space will be allocated or reallocated as necessary and the
    values updated.  The string returned by this function will be
    somewhere within the space at *DATA.  It is safe to deallocate
    this space with free when it is no longer needed.
 
    Like crypt_rn, this function returns a null pointer on failure, not
    a special string.  */
 extern char *crypt_ra (const char *__phrase, const char *__setting,
                        void **__data, int *__size)
 __THROW;
 
 
 /* Generate a string suitable for use as the setting when hashing a
    new passphrase.  PREFIX controls which hash function will be used,
    COUNT controls the computational cost of the hash (for functions
    where this is tunable), and RBYTES should point to NRBYTES bytes of
    random data.  If PREFIX is a null pointer, the current best default
    is used; if RBYTES is a null pointer, random data will be retrieved
    from the operating system if possible.  (Caution: setting PREFIX to
    an *empty string* selects the use of the oldest and least secure
    hash in the library.  Don't do that.)
 
    The string returned is stored in a statically-allocated buffer, and
    will be overwritten if the function is called again.  It is not
    safe to call this function from multiple threads concurrently.
    However, within a single thread, it is safe to pass the string as
    the SETTING argument to crypt without copying it first; the two
    functions use separate buffers.
 
    If an error occurs (e.g. a prefix that does not correspond to a
    supported hash function, or an inadequate amount of random data),
    this function returns a null pointer.  */
 extern char *crypt_gensalt (const char *__prefix, unsigned long __count,
                             const char *__rbytes, int __nrbytes)
 __THROW;
 
 /* Thread-safe version of crypt_gensalt; instead of a
    statically-allocated buffer, the generated setting string is
    written to OUTPUT, which is OUTPUT_SIZE bytes long.  OUTPUT_SIZE
    must be at least CRYPT_GENSALT_OUTPUT_SIZE (see above).
 
    If an error occurs, this function returns a null pointer and writes
    a string that does not correspond to any valid setting into OUTPUT.  */
 extern char *crypt_gensalt_rn (const char *__prefix, unsigned long __count,
                                const char *__rbytes, int __nrbytes,
                                char *__output, int __output_size)
 __THROW;
 
 /* Kept for code compatibility with libxcrypt (v3.1.1 and earlier).
    We intentionally declare the function using a macro here, since
    we actually want to link compiled applications against the
    identical crypt_gensalt_rn function.  */
 #ifndef IN_LIBCRYPT  /* Defined when building libxcrypt. */
 # ifdef __REDIRECT_NTH
 extern char * __REDIRECT_NTH (crypt_gensalt_r, (const char *__prefix,
                               unsigned long __count, const char *__rbytes,
                               int __nrbytes, char *__output,
                               int __output_size), crypt_gensalt_rn);
 # else
 #  define crypt_gensalt_r crypt_gensalt_rn
 # endif
 #endif
 
 /* Another thread-safe version of crypt_gensalt; the generated setting
    string is in storage allocated by malloc, and should be deallocated
    with free when it is no longer needed.  */
 extern char *crypt_gensalt_ra (const char *__prefix, unsigned long __count,
                                const char *__rbytes, int __nrbytes)
 __THROW;
 
 /* Checks whether the given setting is a supported method.
 
    The return value is 0 if there is nothing wrong with this setting.
    Otherwise, it is one of the following constants.  */
 extern int crypt_checksalt (const char *__setting);
 
 /* Constants for checking the return value of the
    crypt_checksalt function.  */
 #define CRYPT_SALT_OK              0
 #define CRYPT_SALT_INVALID         1
 #define CRYPT_SALT_METHOD_DISABLED 2  /* NOT implemented, yet. */
 #define CRYPT_SALT_METHOD_LEGACY   3
 #define CRYPT_SALT_TOO_CHEAP       4  /* NOT implemented, yet. */
 
 /* Convenience function to get the prefix of the preferred hash method,
    which is also used by the crypt_gensalt functions, if their given
    prefix parameter is NULL.
 
    The return value is string that equals the prefix of the preferred
    hash method.  Otherwise, it is NULL.  */
 extern const char *crypt_preferred_method (void);
 
 /* These macros could be checked by portable users of crypt_gensalt*
    functions to find out whether null pointers could be specified
    as PREFIX and RBYTES arguments.  */
 #define CRYPT_GENSALT_IMPLEMENTS_DEFAULT_PREFIX 1
 #define CRYPT_GENSALT_IMPLEMENTS_AUTO_ENTROPY   1
 
 /* These macros can be checked by portable users of libxcrypt
    to find out whether the function is implemented.  */
 #define CRYPT_CHECKSALT_AVAILABLE 1
 #define CRYPT_PREFERRED_METHOD_AVAILABLE 1
 
 /* Version number split in single integers.  */
 #define XCRYPT_VERSION_MAJOR 4
 #define XCRYPT_VERSION_MINOR 4
 
 /* Version number coded into an integer.  */
 #define XCRYPT_VERSION_NUM ((XCRYPT_VERSION_MAJOR << 16) | \
                              XCRYPT_VERSION_MINOR)
 
 /* Version number as a string constant.  */
 #define XCRYPT_VERSION_STR "4.4.35"
 
 __END_DECLS
 
 #endif /* crypt.h */

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