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OSSL_CMP_log_open(3)                OpenSSL               OSSL_CMP_log_open(3)



NAME
       OSSL_CMP_log_open, OSSL_CMP_log_close, OSSL_CMP_severity,
       OSSL_CMP_LOG_EMERG, OSSL_CMP_LOG_ALERT, OSSL_CMP_LOG_CRIT,
       OSSL_CMP_LOG_ERR, OSSL_CMP_LOG_WARNING, OSSL_CMP_LOG_NOTICE,
       OSSL_CMP_LOG_INFO, OSSL_CMP_LOG_DEBUG, OSSL_CMP_LOG_TRACE,

       OSSL_CMP_log_cb_t, OSSL_CMP_print_to_bio, OSSL_CMP_print_errors_cb -
       functions for logging and error reporting

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/cmp_util.h>

        int  OSSL_CMP_log_open(void);
        void OSSL_CMP_log_close(void);

        /* severity level declarations resemble those from syslog.h */
        typedef int OSSL_CMP_severity;
        #define OSSL_CMP_LOG_EMERG   0
        #define OSSL_CMP_LOG_ALERT   1
        #define OSSL_CMP_LOG_CRIT    2
        #define OSSL_CMP_LOG_ERR     3
        #define OSSL_CMP_LOG_WARNING 4
        #define OSSL_CMP_LOG_NOTICE  5
        #define OSSL_CMP_LOG_INFO    6
        #define OSSL_CMP_LOG_DEBUG   7
        #define OSSL_CMP_LOG_TRACE   8

        typedef int (*OSSL_CMP_log_cb_t)(const char *component,
                                         const char *file, int line,
                                         OSSL_CMP_severity level, const char *msg);
        int OSSL_CMP_print_to_bio(BIO *bio, const char *component, const char *file,
                                  int line, OSSL_CMP_severity level, const char *msg);
        void OSSL_CMP_print_errors_cb(OSSL_CMP_log_cb_t log_fn);

DESCRIPTION
       The logging and error reporting facility described here contains
       convenience functions for CMP-specific logging, including a string
       prefix mirroring the severity levels of syslog.h, and enhancements of
       the error queue mechanism needed for large diagnostic messages produced
       by the CMP library in case of certificate validation failures.

       When an interesting activity is performed or an error occurs, some
       detail should be provided for user information, debugging, and auditing
       purposes.  A CMP application can obtain this information by providing a
       callback function with the following type:

        typedef int (*OSSL_CMP_log_cb_t)(const char *component,
                                         const char *file, int line,
                                         OSSL_CMP_severity level, const char *msg);

       The parameters may provide some component info (which may be a module
       name and/or function name) or NULL, a file pathname or NULL, a line
       number or 0 indicating the source code location, a severity level, and
       a message string describing the nature of the event, terminated by
       '\n'.

       Even when an activity is successful some warnings may be useful and
       some degree of auditing may be required. Therefore, the logging
       facility supports a severity level and the callback function has a
       level parameter indicating such a level, such that error, warning,
       info, debug, etc. can be treated differently.  The callback is
       activated only when the severity level is sufficient according to the
       current level of verbosity, which by default is OSSL_CMP_LOG_INFO.

       The callback function may itself do non-trivial tasks like writing to a
       log file or remote stream, which in turn may fail.  Therefore, the
       function should return 1 on success and 0 on failure.

       OSSL_CMP_log_open() initializes the CMP-specific logging facility to
       output everything to STDOUT. It fails if the integrated tracing is
       disabled or STDIO is not available. It may be called during application
       startup.  Alternatively, OSSL_CMP_CTX_set_log_cb(3) can be used for
       more flexibility.  As long as neither if the two is used any logging
       output is ignored.

       OSSL_CMP_log_close() may be called when all activities are finished to
       flush any pending CMP-specific log output and deallocate related
       resources.  It may be called multiple times. It does get called at
       OpenSSL shutdown.

       OSSL_CMP_print_to_bio() prints the given component info, filename, line
       number, severity level, and log message or error queue message to the
       given bio.  component usually is a function or module name.  If it is
       NULL, empty, or "(unknown function)" then "CMP" is used as fallback.

       OSSL_CMP_print_errors_cb() outputs any entries in the OpenSSL error
       queue.  It is similar to ERR_print_errors_cb(3) but uses the CMP log
       callback function log_fn for uniformity with CMP logging if not NULL.
       Otherwise it prints to STDERR using OSSL_CMP_print_to_bio(3) (unless
       OPENSSL_NO_STDIO is defined).

RETURN VALUES
       OSSL_CMP_log_close() and OSSL_CMP_print_errors_cb() do not return
       anything.

       All other functions return 1 on success, 0 on error.

HISTORY
       The OpenSSL CMP support was added in OpenSSL 3.0.

COPYRIGHT
       Copyright 2007-2023 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



3.0.12                            2023-10-25              OSSL_CMP_log_open(3)