diff options
author | Ulf Möller <ulf@openssl.org> | 2000-02-01 01:37:00 +0000 |
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committer | Ulf Möller <ulf@openssl.org> | 2000-02-01 01:37:00 +0000 |
commit | 388f2f56f213dfada0370d48cb9bcc3c7e980b32 (patch) | |
tree | 587fe7258e54967024947b1da5c0851faf819276 /doc/crypto/err.pod | |
parent | f5a8d67872fe2c58626a2423c3ec923f8c2a5d4a (diff) |
Document ERR library.
Diffstat (limited to 'doc/crypto/err.pod')
-rw-r--r-- | doc/crypto/err.pod | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/doc/crypto/err.pod b/doc/crypto/err.pod new file mode 100644 index 0000000000..5b0c4698cb --- /dev/null +++ b/doc/crypto/err.pod @@ -0,0 +1,130 @@ +=pod + +=head1 NAME + +err - Error codes + +=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_free_strings(void); + + void ERR_remove_state(unsigned long pid); + + 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); + +=head1 DESCRIPTION + +When a call to the OpenSSL library fails, this is usually signalled +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. + +The L<ERR_get_error(3)|ERR_get_error(3)> manpage describes how to +access error codes. + +Error codes contain information about where the error occurred, and +what went wrong. L<ERR_GET_LIB(3)|ERR_GET_LIB(3)> describes how to +extract this information. A method to obtain human-readable error +messages is described in L<ERR_error_string(3)|ERR_error_string(3)>. + +L<ERR_clear_error(3)|ERR_clear_error(3)> can be used to clear the +error queue. + +Note that L<ERR_remove_state(3)|ERR_remove_state(3)> should be used to +avoid memory leaks when threads are terminated. + +=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 +new functionality to OpenSSL. + +=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 +descriptions. For example, the function ssl23_read() reports a +"handshake failure" as follows: + + SSLerr(SSL_F_SSL23_READ, SSL_R_SSL_HANDSHAKE_FAILURE); + +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. + +=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>. + +=head1 INTERNALS + +The error queues are stored in a hash table with one B<ERR_STATE> +entry for each pid. ERR_get_state() returns the current thread's +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. + +Error strings are also stored in hash table. The hash tables can +be obtained by calling ERR_get_err_state_table(void) and +ERR_get_string_table(void) respectively. + +=head1 SEE ALSO + +L<ERR_get_error(3)|ERR_get_error(3)>, +L<ERR_GET_LIB(3)|ERR_GET_LIB(3)>, +L<ERR_clear_error(3)|ERR_clear_error(3)>, +L<ERR_error_string(3)|ERR_error_string(3)>, +L<ERR_print_errors(3)|ERR_print_errors(3)>, +L<ERR_load_crypto_strings(3)|ERR_load_crypto_strings(3)>, +L<ERR_remove_state(3)|ERR_remove_state(3)>, +L<ERR_put_error(3)|ERR_put_error(3)>, +L<ERR_load_strings(3)|ERR_load_strings(3)>, +L<SSL_get_error(3)|SSL_get_error(3)> + +=cut |