err.pod 6.7 KB
Newer Older
U
Ulf Möller 已提交
1 2 3 4
=pod

=head1 NAME

U
Ulf Möller 已提交
5
err - error codes
U
Ulf Möller 已提交
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

=head1 SYNOPSIS

 #include <openssl/err.h>

 unsigned long ERR_get_error(void);
 unsigned long ERR_peek_error(void);
 unsigned long ERR_get_error_line(const char **file, int *line);
 unsigned long ERR_peek_error_line(const char **file, int *line);
 unsigned long ERR_get_error_line_data(const char **file, int *line,
         const char **data, int *flags);
 unsigned long ERR_peek_error_line_data(const char **file, int *line,
         const char **data, int *flags);

 int ERR_GET_LIB(unsigned long e);
 int ERR_GET_FUNC(unsigned long e);
 int ERR_GET_REASON(unsigned long e);

 void ERR_clear_error(void);

 char *ERR_error_string(unsigned long e, char *buf);
 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);

 void ERR_print_errors(BIO *bp);
 void ERR_print_errors_fp(FILE *fp);

 void ERR_load_crypto_strings(void);

 void ERR_put_error(int lib, int func, int reason, const char *file,
         int line);
 void ERR_add_error_data(int num, ...);

 void ERR_load_strings(int lib,ERR_STRING_DATA str[]);
 unsigned long ERR_PACK(int lib, int func, int reason);
 int ERR_get_next_error_library(void);

44 45 46 47 48 49
Deprecated:

 #if OPENSSL_API_COMPAT < 0x10000000L
 void ERR_remove_state(unsigned long pid);
 #endif

50 51 52 53
 #if OPENSSL_API_COMPAT < 0x10100000L
 void ERR_remove_thread_state(void *);
 #endif

54
 #if OPENSSL_API_COMPAT < 0x10100000L
55
 void ERR_free_strings(void)
56 57 58
 #endif


U
Ulf Möller 已提交
59 60
=head1 DESCRIPTION

61
When a call to the OpenSSL library fails, this is usually signaled
U
Ulf Möller 已提交
62 63 64 65
by the return value, and an error code is stored in an error queue
associated with the current thread. The B<err> library provides
functions to obtain these error codes and textual error messages.

R
Rich Salz 已提交
66
The L<ERR_get_error(3)> manpage describes how to
U
Ulf Möller 已提交
67 68 69
access error codes.

Error codes contain information about where the error occurred, and
R
Rich Salz 已提交
70
what went wrong. L<ERR_GET_LIB(3)> describes how to
U
Ulf Möller 已提交
71
extract this information. A method to obtain human-readable error
R
Rich Salz 已提交
72
messages is described in L<ERR_error_string(3)>.
U
Ulf Möller 已提交
73

R
Rich Salz 已提交
74
L<ERR_clear_error(3)> can be used to clear the
U
Ulf Möller 已提交
75 76 77 78 79 80 81 82
error queue.

=head1 ADDING NEW ERROR CODES TO OPENSSL

See L<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
D
Dr. Stephen Henson 已提交
83
new error codes to OpenSSL or add error codes from external libraries.
U
Ulf Möller 已提交
84 85 86 87 88 89 90

=head2 Reporting errors

Each sub-library has a specific macro XXXerr() that is used to report
errors. Its first argument is a function code B<XXX_F_...>, the second
argument is a reason code B<XXX_R_...>. Function codes are derived
from the function names; reason codes consist of textual error
91
descriptions. For example, the function ssl3_read_bytes() reports a
U
Ulf Möller 已提交
92 93
"handshake failure" as follows:

94
 SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_SSL_HANDSHAKE_FAILURE);
U
Ulf Möller 已提交
95

D
 
Dr. Stephen Henson 已提交
96 97 98 99
Function and reason codes should consist of upper case characters,
numbers and underscores only. The error file generation script translates
function codes into function names by looking in the header files
for an appropriate function name, if none is found it just uses
100
the capitalized form such as "SSL3_READ_BYTES" in the above example.
D
 
Dr. Stephen Henson 已提交
101 102

The trailing section of a reason code (after the "_R_") is translated
U
Ulf Möller 已提交
103
into lower case and underscores changed to spaces.
D
 
Dr. Stephen Henson 已提交
104

U
Ulf Möller 已提交
105 106 107 108
When you are using new function or reason codes, run B<make errors>.
The necessary B<#define>s will then automatically be added to the
sub-library's header file.

D
Dr. Stephen Henson 已提交
109
Although a library will normally report errors using its own specific
D
 
Dr. Stephen Henson 已提交
110 111 112
XXXerr macro, another library's macro can be used. This is normally
only done when a library wants to include ASN1 code which must use
the ASN1err() macro.
D
Dr. Stephen Henson 已提交
113

U
Ulf Möller 已提交
114 115 116 117 118 119 120 121 122 123 124 125 126 127
=head2 Adding new libraries

When adding a new sub-library to OpenSSL, assign it a library number
B<ERR_LIB_XXX>, define a macro XXXerr() (both in B<err.h>), add its
name to B<ERR_str_libraries[]> (in B<crypto/err/err.c>), and add
C<ERR_load_XXX_strings()> to the ERR_load_crypto_strings() function
(in B<crypto/err/err_all.c>). Finally, add an entry

 L	XXX	xxx.h	xxx_err.c

to B<crypto/err/openssl.ec>, and add B<xxx_err.c> to the Makefile.
Running B<make errors> will then generate a file B<xxx_err.c>, and
add all error codes used in the library to B<xxx.h>.

D
Dr. Stephen Henson 已提交
128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
Additionally the library include file must have a certain form.
Typically 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 B<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 B<make errors> is run.
The closing #endif etc will be automatically added by the script.

The generated C error code file B<xxx_err.c> will load the header
files B<stdio.h>, B<openssl/err.h> and B<openssl/xxx.h> so the
U
ispell.  
Ulf Möller 已提交
155
header file must load any additional header files containing any
D
Dr. Stephen Henson 已提交
156 157 158 159 160 161 162 163 164 165 166 167 168
definitions it uses.

=head1 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 B<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 ASN1 structures
but it can also be used to add more general purpose error code handling.

TBA more details

U
Ulf Möller 已提交
169 170
=head1 INTERNALS

171 172
The error queues are stored in a thread-local storage with one B<ERR_STATE>
entry for each thread. ERR_get_state() returns the current thread's
U
Ulf Möller 已提交
173 174 175 176
B<ERR_STATE>. An B<ERR_STATE> can hold up to B<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.

177 178
Error strings are also stored in a hash table that can be obtained
by calling ERR_get_string_table(void).
U
Ulf Möller 已提交
179 180 181

=head1 SEE ALSO

R
Rich Salz 已提交
182 183 184 185 186 187 188 189 190 191
L<CRYPTO_set_locking_callback(3)>,
L<ERR_get_error(3)>,
L<ERR_GET_LIB(3)>,
L<ERR_clear_error(3)>,
L<ERR_error_string(3)>,
L<ERR_print_errors(3)>,
L<ERR_load_crypto_strings(3)>,
L<ERR_put_error(3)>,
L<ERR_load_strings(3)>,
L<SSL_get_error(3)>
U
Ulf Möller 已提交
192

193 194 195 196 197
=head1 HISTORY

The ERR_load_crypto_strings() function was deprecated in OpenSSL 1.1.0 by
OPENSSL_init_crypto().

U
Ulf Möller 已提交
198
=cut
R
Rich Salz 已提交
199 200 201 202 203 204 205 206 207 208 209

=head1 COPYRIGHT

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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
L<https://www.openssl.org/source/license.html>.

=cut