crypt_gensalt(3c)

1crypt_gensalt(3C)        Standard C Library Functions        crypt_gensalt(3C)
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NAME

6       crypt_gensalt - generate salt string for string encoding
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SYNOPSIS

9       #include <crypt.h>
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11       char *crypt_gensalt(const char *oldsalt, const struct passwd *userinfo);
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DESCRIPTION

15       The  crypt_gensalt()  function  generates  the  salt string required by
16       crypt(3C).
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19       If oldsalt is NULL,  crypt_gensalt()  uses  the  algorithm  defined  by
20       CRYPT_DEFAULT in /etc/security/policy.conf. See policy.conf(4).
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23       If  oldsalt  is  non-null,  crypt_gensalt() determines if the algorithm
24       specified  by  oldsalt  is  allowable  by  checking   the   CRYPT_ALGO‐
25       RITHMS_ALLOW  and  CRYPT_ALGORITHMS_DEPRECATE  variables  in /etc/secu‐
26       rity/policy.conf. If the algorithm is  allowed,  crypt_gensalt()  loads
27       the appropriate shared library and calls crypt_gensalt_impl(3C). If the
28       algorithm is not allowed or there is no entry  for  it  in  crypt.conf,
29       crypt_gensalt() uses the default algorithm.
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32       The  mechanism  just described provides a means to migrate users to new
33       password hashing algorithms when the password is changed.
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RETURN VALUES

36       Upon successful completion, crypt_gensalt() returns a  pointer  to  the
37       new  salt.  Otherwise  a  null  pointer is returned and errno is set to
38       indicate the error.
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ERRORS

41       The crypt_gensalt() function will fail if:
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43       EINVAL     The configuration file crypt.conf contains an invalid entry.
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46       ELIBACC    The required shared library was not found.
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49       ENOMEM     There is insufficient memory to perform hashing.
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USAGE

53       The value returned  by  crypt_gensalt()  points  to  a  null-terminated
54       string.  The  caller  of  crypt_gensalt()  is  responsible  for calling
55       free(3C).
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58       Applications dealing with user  authentication  and  password  changing
59       should  not  call  crypt_gensalt() directly but should instead call the
60       appropriate pam(3PAM) functions.
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ATTRIBUTES

63       See attributes(5) for descriptions of the following attributes:
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68       ┌─────────────────────────────┬─────────────────────────────┐
69       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
70       ├─────────────────────────────┼─────────────────────────────┤
71       │Interface Stability          │Evolving                     │
72       ├─────────────────────────────┼─────────────────────────────┤
73       │MT-Level                     │MT-Safe                      │
74       └─────────────────────────────┴─────────────────────────────┘
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