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/* $OpenBSD: test-run-down.c,v 1.2 2019/11/14 21:17:00 anton Exp $ */
/*
* Copyright (c) 2019 Anton Lindqvist <anton@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <err.h>
#include <errno.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include "pipe.h"
struct context {
int c_pipe[2];
char *c_buf;
size_t c_bufsiz;
unsigned int c_nsyscalls;
pthread_cond_t c_cv;
pthread_mutex_t c_mtx;
};
static void ctx_setup(struct context *, size_t);
static void ctx_teardown(struct context *);
static void ctx_lock(struct context *);
static void ctx_unlock(struct context *);
static int test_run_down(size_t);
static void *write_thread(void *);
/*
* Verify delivery of SIGPIPE while trying to write on a pipe where the read end
* is gone.
*
* The writer thread first of writes BIG_PIPE_SIZE number of bytes and then
* tries to perform the same operation again. The ambition is to cause the
* writer thread to go to sleep since the pipe capacity is exhausted. The main
* thread closes the read end at this point causing the writer thread to wake up
* and punt.
*/
int
test_run_down_write_big()
{
return test_run_down(BIG_PIPE_SIZE);
}
/*
* Verify delivery of SIGPIPE while trying to write on a pipe where the read end
* is gone.
*
* The writer thread writes a single byte continously while the main thread ends
* up closing the read end after at least a single byte has been written. The
* ambition is not to make the writer thread go to sleep but rather punt early
* while writing since the read end is gone.
*/
int
test_run_down_write_small()
{
return test_run_down(1);
}
static void
ctx_setup(struct context *ctx, size_t bufsiz)
{
int error;
if (pipe(ctx->c_pipe) == -1)
err(1, "pipe");
ctx->c_buf = malloc(bufsiz);
if (ctx->c_buf == NULL)
err(1, NULL);
ctx->c_bufsiz = bufsiz;
ctx->c_nsyscalls = 0;
error = pthread_cond_init(&ctx->c_cv, NULL);
if (error)
errc(1, error, "pthread_cond_init");
error = pthread_mutex_init(&ctx->c_mtx, NULL);
if (error)
errc(1, error, "pthread_mutex_init");
}
static void
ctx_teardown(struct context *ctx)
{
int error;
if (ctx->c_pipe[0] != -1)
close(ctx->c_pipe[0]);
ctx->c_pipe[0] = -1;
if (ctx->c_pipe[1] != -1)
close(ctx->c_pipe[1]);
ctx->c_pipe[1] = -1;
free(ctx->c_buf);
error = pthread_cond_destroy(&ctx->c_cv);
if (error)
errc(1, error, "pthread_cond_destroy");
error = pthread_mutex_destroy(&ctx->c_mtx);
if (error)
errc(1, error, "pthread_mutex_destroy");
}
static void
ctx_lock(struct context *ctx)
{
int error;
error = pthread_mutex_lock(&ctx->c_mtx);
if (error)
errc(1, error, "pthread_mutex_lock");
}
static void ctx_unlock(struct context *ctx)
{
int error;
error = pthread_mutex_unlock(&ctx->c_mtx);
if (error)
errc(1, error, "pthread_mutex_unlock");
}
static int
test_run_down(size_t bufsiz)
{
struct context ctx;
pthread_t th;
int error;
ctx_setup(&ctx, bufsiz);
error = pthread_create(&th, NULL, write_thread, &ctx);
if (error)
errc(1, error, "pthread_create");
ctx_lock(&ctx);
for (;;) {
if (ctx.c_nsyscalls > 0)
break;
error = pthread_cond_wait(&ctx.c_cv, &ctx.c_mtx);
if (error)
errc(1, error, "pthread_cond_wait");
}
ctx_unlock(&ctx);
/* Signal shutdown to the write thread. */
close(ctx.c_pipe[0]);
ctx.c_pipe[0] = -1;
error = pthread_join(th, NULL);
if (error)
errc(1, error, "pthread_join");
if (!gotsigpipe)
errx(1, "no SIGPIPE");
ctx_teardown(&ctx);
return 0;
}
static void *
write_thread(void *arg)
{
struct context *ctx = arg;
int error;
for (;;) {
ssize_t n;
n = write(ctx->c_pipe[1], ctx->c_buf, ctx->c_bufsiz);
if (n == -1) {
if (errno == EPIPE)
break;
err(1, "write");
}
ctx_lock(ctx);
ctx->c_nsyscalls++;
ctx_unlock(ctx);
error = pthread_cond_signal(&ctx->c_cv);
if (error)
errc(1, error, "pthread_cond_signal");
}
return NULL;
}
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