bio_queue_tests.c

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/*
 *   This library is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *   Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/** Tests for the queue bio's shutdown and error handling
 *
 * @file src/lib/bio/test/bio_queue_tests.c
 *
 * @copyright 2026 Network RADIUS SAS (legal@networkradius.com)
 */
#include <freeradius-devel/util/test/acutest_common_init.h>
#include <freeradius-devel/util/test/acutest_helpers.h>
 
#include <freeradius-devel/bio/bio_priv.h>
#include <freeradius-devel/bio/mem.h>
#include <freeradius-devel/bio/null.h>
#include <freeradius-devel/bio/pipe.h>
#include <freeradius-devel/bio/queue.h>
 
static int      cancel_count;
static int      shutdown_count;
 
static void     cb_eof(fr_bio_t *bio)           { (void) bio; }
static int      cb_shutdown(fr_bio_t *bio)      { (void) bio; shutdown_count++; return 0; }
static int      cb_noop(fr_bio_t *bio)          { (void) bio; return 0; }
 
static void     queue_cancel(fr_bio_t *bio, void *packet_ctx, void const *buffer, size_t size)
{
        (void) bio; (void) packet_ctx; (void) buffer; (void) size;
        cancel_count++;
}
 
static fr_bio_cb_funcs_t test_cb = {
        .read_resume    = cb_noop,
        .write_resume   = cb_noop,
        .read_blocked   = cb_noop,
        .write_blocked  = cb_noop,
        .eof            = cb_eof,
        .shutdown       = cb_shutdown,
};
 
/*
 *      The pipe holds 1024 bytes, so the second write is partial, and the queue saves it.
 */
static uint8_t  fill[1000];
static uint8_t  overflow[100];
 
/** A stub transport which fails recoverably or fatally, as each test chooses.
 *
 *  On a recoverable failure, the stub returns an error and changes nothing else.  On a fatal failure,
 *  the stub first shuts the chain down, as the fd bio does.  Only the failing bio decides whether a
 *  failure is recoverable or fatal.
 */
typedef struct {
        FR_BIO_COMMON;
        bool            fatal;                  //!< shut the chain down before failing
} stub_t;
 
static ssize_t stub_write_fail(fr_bio_t *bio, UNUSED void *packet_ctx, UNUSED void const *buffer, UNUSED size_t size)
{
        stub_t *stub = (stub_t *) bio;
 
        if (stub->fatal) (void) fr_bio_shutdown(bio);
 
        fr_strerror_const("stub write failure");
        return fr_bio_error(GENERIC);
}
 
/** A transport which accepts one byte of each write, so the queue bio saves the rest of the packet.
 */
static ssize_t stub_write_one(UNUSED fr_bio_t *bio, UNUSED void *packet_ctx, UNUSED void const *buffer, UNUSED size_t size)
{
        return 1;
}
 
/** A transport which accepts every write in full.
 */
static ssize_t stub_write_all(UNUSED fr_bio_t *bio, UNUSED void *packet_ctx, UNUSED void const *buffer, size_t size)
{
        return size;
}
 
static fr_bio_t *stub_alloc(TALLOC_CTX *ctx)
{
        stub_t *stub;
 
        stub = talloc_zero(ctx, stub_t);
        if (!stub) return NULL;
 
        stub->bio.read = fr_bio_null_read;
        stub->bio.write = stub_write_fail;
 
        return &stub->bio;
}
 
/** Leave one packet partly written in the queue.
 */
static bool queue_fill(fr_bio_t *head)
{
        if (fr_bio_write(head, NULL, fill, sizeof(fill)) != sizeof(fill)) return false;
 
        return (fr_bio_write(head, NULL, overflow, sizeof(overflow)) == sizeof(overflow));
}
 
/** The application installs its callbacks on a queue bio at the head of the chain.
 *
 *  The queue's own shutdown routine must survive that, and still cancel the saved packet.
 */
static void test_shutdown_keeps_app_callback(void)
{
        TALLOC_CTX      *ctx = talloc_init_const("test");
        fr_bio_t        *queue, *pipe;
 
        cancel_count = shutdown_count = 0;
 
        pipe = fr_bio_pipe_alloc(ctx, &test_cb, 1024);
        TEST_CHECK(pipe != NULL);
        if (!pipe) goto done;
 
        queue = fr_bio_queue_alloc(ctx, 4, NULL, NULL, queue_cancel, pipe);
        TEST_CHECK(queue != NULL);
        if (!queue) goto done;
 
        fr_bio_cb_set(queue, &test_cb);
 
        TEST_CHECK(queue_fill(queue));
 
        TEST_CASE("the transport dies");
        TEST_CHECK(fr_bio_shutdown(pipe) == 0);
 
        TEST_CASE("the saved packet is cancelled");
        TEST_CHECK_RET(cancel_count, 1);
 
        TEST_CASE("the application is told about the shutdown");
        TEST_CHECK_RET(shutdown_count, 1);
 
        TEST_CASE("writes report SHUTDOWN");
        TEST_CHECK(fr_bio_write(queue, NULL, "x", 1) == fr_bio_error(SHUTDOWN));
 
done:
        talloc_free(ctx);
}
 
/** A queue bio in the middle of a chain is not the head, so only the private slot reaches it.
 */
static void test_shutdown_not_head(void)
{
        TALLOC_CTX      *ctx = talloc_init_const("test");
        fr_bio_t        *head, *queue, *pipe;
 
        cancel_count = shutdown_count = 0;
 
        pipe = fr_bio_pipe_alloc(ctx, &test_cb, 1024);
        TEST_CHECK(pipe != NULL);
        if (!pipe) goto done;
 
        queue = fr_bio_queue_alloc(ctx, 4, NULL, NULL, queue_cancel, pipe);
        TEST_CHECK(queue != NULL);
        if (!queue) goto done;
 
        /*
         *      A memory bio with no buffers passes writes straight through.
         */
        head = fr_bio_mem_alloc(ctx, 0, 0, queue);
        TEST_CHECK(head != NULL);
        if (!head) goto done;
 
        fr_bio_cb_set(head, &test_cb);
 
        TEST_CHECK(queue_fill(head));
 
        TEST_CASE("the transport dies");
        TEST_CHECK(fr_bio_shutdown(pipe) == 0);
 
        TEST_CASE("the saved packet is cancelled");
        TEST_CHECK_RET(cancel_count, 1);
 
        TEST_CASE("the application is told about the shutdown");
        TEST_CHECK_RET(shutdown_count, 1);
 
done:
        talloc_free(ctx);
}
 
/** Build a queue in front of a stub, with one packet saved after a partial write.
 */
static fr_bio_t *test_queue_saved_alloc(TALLOC_CTX *ctx, fr_bio_t **stub_p)
{
        fr_bio_t        *queue, *stub;
 
        cancel_count = shutdown_count = 0;
 
        stub = stub_alloc(ctx);
        if (!stub) return NULL;
 
        queue = fr_bio_queue_alloc(ctx, 4, NULL, NULL, queue_cancel, stub);
        if (!queue) return NULL;
 
        fr_bio_cb_set(queue, &test_cb);
 
        stub->write = stub_write_one;
        if (fr_bio_write(queue, NULL, overflow, sizeof(overflow)) != sizeof(overflow)) return NULL;
 
        *stub_p = stub;
        return queue;
}
 
/** The queue bio passes a recoverable write error up to the application, and keeps working.
 */
static void test_recoverable_write_passes_up(void)
{
        TALLOC_CTX      *ctx = talloc_init_const("test");
        fr_bio_t        *queue, *stub;
 
        cancel_count = shutdown_count = 0;
 
        stub = stub_alloc(ctx);
        TEST_CHECK(stub != NULL);
        if (!stub) goto done;
 
        queue = fr_bio_queue_alloc(ctx, 4, NULL, NULL, queue_cancel, stub);
        TEST_CHECK(queue != NULL);
        if (!queue) goto done;
 
        fr_bio_cb_set(queue, &test_cb);
 
        TEST_CASE("the write gets the error from the stub");
        TEST_CHECK(fr_bio_write(queue, NULL, "x", 1) == fr_bio_error(GENERIC));
 
        TEST_CASE("the queue bio does not shut the chain down");
        TEST_CHECK_RET(shutdown_count, 0);
 
        TEST_CASE("the next write reaches the stub again");
        stub->write = stub_write_all;
        TEST_CHECK_RET((int) fr_bio_write(queue, NULL, "x", 1), 1);
 
done:
        talloc_free(ctx);
}
 
/** The queue bio passes a recoverable flush error up to the application, and keeps the saved packet.
 */
static void test_recoverable_flush_passes_up(void)
{
        TALLOC_CTX      *ctx = talloc_init_const("test");
        fr_bio_t        *queue, *stub = NULL;
 
        queue = test_queue_saved_alloc(ctx, &stub);
        TEST_CHECK(queue != NULL);
        if (!queue) goto done;
 
        TEST_CASE("the flush gets the error from the stub");
        stub->write = stub_write_fail;
        TEST_CHECK(fr_bio_write(queue, NULL, NULL, SIZE_MAX) == fr_bio_error(GENERIC));
 
        TEST_CASE("the saved packet is not cancelled, and the chain is not shut down");
        TEST_CHECK_RET(cancel_count, 0);
        TEST_CHECK_RET(shutdown_count, 0);
 
        TEST_CASE("a later flush sends the saved packet");
        stub->write = stub_write_all;
        TEST_CHECK(fr_bio_write(queue, NULL, NULL, SIZE_MAX) > 0);
        TEST_CHECK_RET(cancel_count, 0);
 
done:
        talloc_free(ctx);
}
 
/** When the next bio shuts the chain down on a fatal flush error, fr_bio_queue_shutdown() cancels the saved packet.
 */
static void test_fatal_flush_from_next(void)
{
        TALLOC_CTX      *ctx = talloc_init_const("test");
        fr_bio_t        *queue, *stub = NULL;
 
        queue = test_queue_saved_alloc(ctx, &stub);
        TEST_CHECK(queue != NULL);
        if (!queue) goto done;
 
        TEST_CASE("the flush gets the error from the stub");
        ((stub_t *) stub)->fatal = true;
        stub->write = stub_write_fail;
        TEST_CHECK(fr_bio_write(queue, NULL, NULL, SIZE_MAX) == fr_bio_error(GENERIC));
 
        TEST_CASE("fr_bio_queue_shutdown() cancels the saved packet, and the application is told");
        TEST_CHECK_RET(cancel_count, 1);
        TEST_CHECK_RET(shutdown_count, 1);
 
        TEST_CASE("later writes report SHUTDOWN");
        TEST_CHECK(fr_bio_write(queue, NULL, "x", 1) == fr_bio_error(SHUTDOWN));
 
done:
        talloc_free(ctx);
}
 
TEST_LIST = {
        { "shutdown_keeps_app_callback",        test_shutdown_keeps_app_callback },
        { "shutdown_not_head",                  test_shutdown_not_head },
        { "recoverable_write_passes_up",        test_recoverable_write_passes_up },
        { "recoverable_flush_passes_up",        test_recoverable_flush_passes_up },
        { "fatal_flush_from_next",              test_fatal_flush_from_next },
        TEST_TERMINATOR
};