xref: /freebsd/secure/lib/libcrypto/man/man3/OSSL_STORE_open.3 (revision 5956d97f4b3204318ceb6aa9c77bd0bc6ea87a41)
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Title "OSSL_STORE_OPEN 3"
OSSL_STORE_OPEN 3 "2022-07-05" "1.1.1q" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
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"NAME"
OSSL_STORE_CTX, OSSL_STORE_post_process_info_fn, OSSL_STORE_open, OSSL_STORE_ctrl, OSSL_STORE_load, OSSL_STORE_eof, OSSL_STORE_error, OSSL_STORE_close - Types and functions to read objects from a URI
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/store.h> \& typedef struct ossl_store_ctx_st OSSL_STORE_CTX; \& typedef OSSL_STORE_INFO *(*OSSL_STORE_post_process_info_fn)(OSSL_STORE_INFO *, void *); \& OSSL_STORE_CTX *OSSL_STORE_open(const char *uri, const UI_METHOD *ui_method, void *ui_data, OSSL_STORE_post_process_info_fn post_process, void *post_process_data); int OSSL_STORE_ctrl(OSSL_STORE_CTX *ctx, int cmd, ... /* args */); OSSL_STORE_INFO *OSSL_STORE_load(OSSL_STORE_CTX *ctx); int OSSL_STORE_eof(OSSL_STORE_CTX *ctx); int OSSL_STORE_error(OSSL_STORE_CTX *ctx); int OSSL_STORE_close(OSSL_STORE_CTX *ctx); .Ve
"DESCRIPTION"
Header "DESCRIPTION" These functions help the application to fetch supported objects (see \*(L"\s-1SUPPORTED OBJECTS\*(R"\s0 in \s-1OSSL_STORE_INFO\s0\|(3) for information on which those are) from a given \s-1URI\s0 (see \*(L"\s-1SUPPORTED SCHEMES\*(R"\s0 for more information on the supported \s-1URI\s0 schemes). The general method to do so is to \*(L"open\*(R" the \s-1URI\s0 using OSSL_STORE_open(), read each available and supported object using OSSL_STORE_load() as long as \fBOSSL_STORE_eof() hasn't been reached, and finish it off with OSSL_STORE_close().

The retrieved information is stored in a \s-1OSSL_STORE_INFO\s0, which is further described in \s-1OSSL_STORE_INFO\s0\|(3).

"Types"
Subsection "Types" \fB\s-1OSSL_STORE_CTX\s0 is a context variable that holds all the internal information for OSSL_STORE_open(), OSSL_STORE_load(), OSSL_STORE_eof() and \fBOSSL_STORE_close() to work together.
"Functions"
Subsection "Functions" \fBOSSL_STORE_open() takes a uri or path uri, password \s-1UI\s0 method \fIui_method with associated data ui_data, and post processing callback post_process with associated data post_process_data, opens a channel to the data located at that \s-1URI\s0 and returns a \fB\s-1OSSL_STORE_CTX\s0 with all necessary internal information. The given ui_method and ui_data will be reused by all functions that use \s-1OSSL_STORE_CTX\s0 when interaction is needed, for instance to provide a password. The given post_process and post_process_data will be reused by \fBOSSL_STORE_load() to manipulate or drop the value to be returned. The post_process function drops values by returning \s-1NULL,\s0 which will cause OSSL_STORE_load() to start its process over with loading the next object, until post_process returns something other than \s-1NULL,\s0 or the end of data is reached as indicated by OSSL_STORE_eof().

\fBOSSL_STORE_ctrl() takes a \s-1OSSL_STORE_CTX\s0, and command number cmd and more arguments not specified here. The available loader specific command numbers and arguments they each take depends on the loader that's used and is documented together with that loader.

There are also global controls available:

"\s-1OSSL_STORE_C_USE_SECMEM\s0" 4
Item "OSSL_STORE_C_USE_SECMEM" Controls if the loader should attempt to use secure memory for any allocated \s-1OSSL_STORE_INFO\s0 and its contents. This control expects one argument, a pointer to an int that is expected to have the value 1 (yes) or 0 (no). Any other value is an error.

\fBOSSL_STORE_load() takes a \s-1OSSL_STORE_CTX\s0, tries to load the next available object and return it wrapped with \s-1OSSL_STORE_INFO\s0.

\fBOSSL_STORE_eof() takes a \s-1OSSL_STORE_CTX\s0 and checks if we've reached the end of data.

\fBOSSL_STORE_error() takes a \s-1OSSL_STORE_CTX\s0 and checks if an error occurred in the last OSSL_STORE_load() call. Note that it may still be meaningful to try and load more objects, unless \fBOSSL_STORE_eof() shows that the end of data has been reached.

\fBOSSL_STORE_close() takes a \s-1OSSL_STORE_CTX\s0, closes the channel that was opened by OSSL_STORE_open() and frees all other information that was stored in the \fB\s-1OSSL_STORE_CTX\s0, as well as the \s-1OSSL_STORE_CTX\s0 itself. If ctx is \s-1NULL\s0 it does nothing.

"SUPPORTED SCHEMES"
Header "SUPPORTED SCHEMES" The basic supported scheme is file:. Any other scheme can be added dynamically, using \fBOSSL_STORE_register_loader().
"NOTES"
Header "NOTES" A string without a scheme prefix (that is, a non-URI string) is implicitly interpreted as using the file: scheme.

There are some tools that can be used together with \fBOSSL_STORE_open() to determine if any failure is caused by an unparsable \s-1URI,\s0 or if it's a different error (such as memory allocation failures); if the \s-1URI\s0 was parsable but the scheme unregistered, the top error will have the reason \*(C`OSSL_STORE_R_UNREGISTERED_SCHEME\*(C'.

These functions make no direct assumption regarding the pass phrase received from the password callback. The loaders may make assumptions, however. For example, the file: scheme loader inherits the assumptions made by OpenSSL functionality that handles the different file types; this is mostly relevant for PKCS#12 objects. See passphrase-encoding\|(7) for further information.

"RETURN VALUES"
Header "RETURN VALUES" \fBOSSL_STORE_open() returns a pointer to a \s-1OSSL_STORE_CTX\s0 on success, or \s-1NULL\s0 on failure.

\fBOSSL_STORE_load() returns a pointer to a \s-1OSSL_STORE_INFO\s0 on success, or \s-1NULL\s0 on error or when end of data is reached. Use OSSL_STORE_error() and OSSL_STORE_eof() to determine the meaning of a returned \s-1NULL.\s0

\fBOSSL_STORE_eof() returns 1 if the end of data has been reached, otherwise 0.

\fBOSSL_STORE_error() returns 1 if an error occurred in an OSSL_STORE_load() call, otherwise 0.

\fBOSSL_STORE_ctrl() and OSSL_STORE_close() returns 1 on success, or 0 on failure.

"SEE ALSO"
Header "SEE ALSO" \fBossl_store\|(7), \s-1OSSL_STORE_INFO\s0\|(3), OSSL_STORE_register_loader\|(3), \fBpassphrase-encoding\|(7)
"HISTORY"
Header "HISTORY" \s-1OSSL_STORE_CTX\s0(), OSSL_STORE_post_process_info_fn(), OSSL_STORE_open(), \fBOSSL_STORE_ctrl(), OSSL_STORE_load(), OSSL_STORE_eof() and OSSL_STORE_close() were added in OpenSSL 1.1.1.

Handling of \s-1NULL\s0 ctx argument for OSSL_STORE_close() was introduced in OpenSSL 1.1.1h.

"COPYRIGHT"
Header "COPYRIGHT" Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.