DragonFly On-Line Manual Pages
ERR(3) DragonFly Library Functions Manual ERR(3)
NAME
ERR -- OpenSSL error codes
SYNOPSIS
#include <openssl/err.h>
DESCRIPTION
When a call to the OpenSSL library fails, this is usually signaled by the
return value, and an error code is stored in an error queue associated
with the current thread. The ERR library provides functions to obtain
these error codes and textual error messages. The ERR_get_error(3) man-
page describes how to access error codes.
Error codes contain information about where the error occurred, and what
went wrong. ERR_GET_LIB(3) describes how to extract this information. A
method to obtain human-readable error messages is described in
ERR_error_string(3).
ERR_clear_error(3) can be used to clear the error queue.
Note that ERR_remove_state(3) should be used to avoid memory leaks when
threads are terminated.
ADDING NEW ERROR CODES TO OPENSSL
See ERR_put_error(3) if you want to record error codes in the OpenSSL
error system from within your application.
The remainder of this section is of interest only if you want to add new
error codes to OpenSSL or add error codes from external libraries.
When you are using new function or reason codes, run make errors. The
necessary #defines will then automatically be added to the sub-library's
header file.
Adding new libraries
When adding a new sub-library to OpenSSL, assign it a library number
ERR_LIB_XXX, define a macro XXXerr() (both in <openssl/err.h>), add its
name to ERR_str_libraries[] (in /usr/src/lib/libcrypto/err/err.c), and
add ERR_load_XXX_strings() to the ERR_load_crypto_strings() function (in
/usr/src/lib/libcrypto/err/err_all.c). Finally, add an entry
L XXX xxx.h xxx_err.c
to /usr/src/lib/libcrypto/err/openssl.ec, and add xxx_err.c to the
Makefile. Running make errors will then generate a file xxx_err.c, and
add all error codes used in the library to xxx.h.
Additionally the library include file must have a certain form. Typi-
cally it will initially look like this:
#ifndef HEADER_XXX_H
#define HEADER_XXX_H
#ifdef __cplusplus
extern "C" {
#endif
/* Include files */
#include <openssl/bio.h>
#include <openssl/x509.h>
/* Macros, structures and function prototypes */
/* BEGIN ERROR CODES */
The BEGIN ERROR CODES sequence is used by the error code generation
script as the point to place new error codes. Any text after this point
will be overwritten when make errors is run. The closing #endif etc.
will be automatically added by the script.
The generated C error code file xxx_err.c will load the header files
<stdio.h>, <openssl/err.h> and <openssl/xxx.h> so the header file must
load any additional header files containing any definitions it uses.
USING ERROR CODES IN EXTERNAL LIBRARIES
It is also possible to use OpenSSL's error code scheme in external
libraries. The library needs to load its own codes and call the OpenSSL
error code insertion script mkerr.pl explicitly to add codes to the
header file and generate the C error code file. This will normally be
done if the external library needs to generate new ASN.1 structures but
it can also be used to add more general purpose error code handling.
INTERNALS
The error queues are stored in a hash table with one ERR_STATE entry for
each PID. ERR_get_state() returns the current thread's ERR_STATE. An
ERR_STATE can hold up to ERR_NUM_ERRORS error codes. When more error
codes are added, the old ones are overwritten, on the assumption that the
most recent errors are most important.
Error strings are also stored in a hash table. The hash tables can be
obtained by calling ERR_get_err_state_table() and ERR_get_string_table().
SEE ALSO
CRYPTO_set_locking_callback(3), ERR_clear_error(3), ERR_error_string(3),
ERR_get_error(3), ERR_GET_LIB(3), ERR_load_crypto_strings(3),
ERR_load_strings(3), ERR_print_errors(3), ERR_put_error(3),
ERR_remove_state(3), ERR_set_mark(3), SSL_get_error(3)
DragonFly 5.5 November 23, 2016 DragonFly 5.5
ERR_error_string(3) OpenSSL ERR_error_string(3)
NAME
ERR_error_string, ERR_error_string_n, ERR_lib_error_string,
ERR_func_error_string, ERR_reason_error_string - obtain human-readable
error message
SYNOPSIS
#include <openssl/err.h>
char *ERR_error_string(unsigned long e, char *buf);
void ERR_error_string_n(unsigned long e, char *buf, size_t len);
const char *ERR_lib_error_string(unsigned long e);
const char *ERR_func_error_string(unsigned long e);
const char *ERR_reason_error_string(unsigned long e);
DESCRIPTION
ERR_error_string() generates a human-readable string representing the
error code e, and places it at buf. buf must be at least 120 bytes
long. If buf is NULL, the error string is placed in a static buffer.
ERR_error_string_n() is a variant of ERR_error_string() that writes at
most len characters (including the terminating 0) and truncates the
string if necessary. For ERR_error_string_n(), buf may not be NULL.
The string will have the following format:
error:[error code]:[library name]:[function name]:[reason string]
error code is an 8 digit hexadecimal number, library name, function
name and reason string are ASCII text.
ERR_lib_error_string(), ERR_func_error_string() and
ERR_reason_error_string() return the library name, function name and
reason string respectively.
The OpenSSL error strings should be loaded by calling
ERR_load_crypto_strings(3) or, for SSL applications,
SSL_load_error_strings(3) first. If there is no text string registered
for the given error code, the error string will contain the numeric
code.
ERR_print_errors(3) can be used to print all error codes currently in
the queue.
RETURN VALUES
ERR_error_string() returns a pointer to a static buffer containing the
string if buf == NULL, buf otherwise.
ERR_lib_error_string(), ERR_func_error_string() and
ERR_reason_error_string() return the strings, and NULL if none is
registered for the error code.
SEE ALSO
err(3), ERR_get_error(3), ERR_load_crypto_strings(3),
SSL_load_error_strings(3) ERR_print_errors(3)
HISTORY
ERR_error_string() is available in all versions of SSLeay and OpenSSL.
ERR_error_string_n() was added in OpenSSL 0.9.6.
1.0.2h 2016-05-03 ERR_error_string(3)