/* forktest.c: FORK SAFETY TEST
*
* $Id: //info.ravenbrook.com/project/mps/branch/2018-06-13/fork/code/tagtest.c#1 $
* Copyright (c) 2018-2020 Ravenbrook Limited. See end of file for license.
*
* .overview: This test case is a regression test for job004062. It
* checks that the MPS correctly runs in the child process after a
* fork() on FreeBSD, Linux or macOS.
*
* .format: This test case uses a trivial object format in which each
* object contains a single reference.
*/
#include <stdio.h>
#include <sys/wait.h>
#include <unistd.h>
#include "mps.h"
#include "mpsavm.h"
#include "mpscamc.h"
#include "testlib.h"
enum {
TYPE_REF,
TYPE_FWD,
TYPE_PAD
};
typedef struct obj_s {
unsigned type; /* One of the TYPE_ enums */
union {
struct obj_s *ref; /* TYPE_REF */
mps_addr_t fwd; /* TYPE_FWD */
size_t pad; /* TYPE_PAD */
} u;
} obj_s, *obj_t;
static void obj_fwd(mps_addr_t old, mps_addr_t new)
{
obj_t obj = old;
obj->type = TYPE_FWD;
obj->u.fwd = new;
}
static mps_addr_t obj_isfwd(mps_addr_t addr)
{
obj_t obj = addr;
if (obj->type == TYPE_FWD) {
return obj->u.fwd;
} else {
return NULL;
}
}
static void obj_pad(mps_addr_t addr, size_t size)
{
obj_t obj = addr;
obj->type = TYPE_PAD;
obj->u.pad = size;
}
static mps_addr_t obj_skip(mps_addr_t addr)
{
obj_t obj = addr;
size_t size;
if (obj->type == TYPE_PAD) {
size = obj->u.pad;
} else {
size = sizeof(obj_s);
}
return (char *)addr + size;
}
static mps_res_t obj_scan(mps_ss_t ss, mps_addr_t base, mps_addr_t limit)
{
MPS_SCAN_BEGIN(ss) {
while (base < limit) {
obj_t obj = base;
if (obj->type == TYPE_REF) {
mps_addr_t p = obj->u.ref;
mps_res_t res = MPS_FIX12(ss, &p);
if (res != MPS_RES_OK) {
return res;
}
obj->u.ref = p;
}
base = obj_skip(base);
}
} MPS_SCAN_END(ss);
return MPS_RES_OK;
}
int main(int argc, char *argv[])
{
void *marker = ▮
int pid;
mps_arena_t arena;
mps_fmt_t obj_fmt;
mps_pool_t pool;
mps_thr_t thread;
mps_root_t stack_root;
mps_ap_t obj_ap;
size_t i;
obj_t obj, first;
testlib_init(argc, argv);
/* Set the pause time to be very small so that the incremental
collector (when it runs) will have to leave a read barrier in
place for us to hit. */
MPS_ARGS_BEGIN(args) {
MPS_ARGS_ADD(args, MPS_KEY_PAUSE_TIME, 0.0);
die(mps_arena_create_k(&arena, mps_arena_class_vm(), args),
"mps_arena_create");
} MPS_ARGS_END(args);
mps_arena_park(arena);
die(mps_thread_reg(&thread, arena), "Couldn't register thread");
die(mps_root_create_thread(&stack_root, arena, thread, marker),
"Couldn't create thread root");
MPS_ARGS_BEGIN(args) {
MPS_ARGS_ADD(args, MPS_KEY_FMT_ALIGN, sizeof(obj_s));
MPS_ARGS_ADD(args, MPS_KEY_FMT_SCAN, obj_scan);
MPS_ARGS_ADD(args, MPS_KEY_FMT_SKIP, obj_skip);
MPS_ARGS_ADD(args, MPS_KEY_FMT_FWD, obj_fwd);
MPS_ARGS_ADD(args, MPS_KEY_FMT_ISFWD, obj_isfwd);
MPS_ARGS_ADD(args, MPS_KEY_FMT_PAD, obj_pad);
die(mps_fmt_create_k(&obj_fmt, arena, args), "Couldn't create obj format");
} MPS_ARGS_END(args);
MPS_ARGS_BEGIN(args) {
MPS_ARGS_ADD(args, MPS_KEY_FORMAT, obj_fmt);
die(mps_pool_create_k(&pool, arena, mps_class_amc(), args),
"Couldn't create pool");
} MPS_ARGS_END(args);
die(mps_ap_create_k(&obj_ap, pool, mps_args_none),
"Couldn't create obj allocation point");
/* Create a linked list of objects. */
first = NULL;
for (i = 0; i < 100000; ++i) {
size_t size = sizeof(obj_s);
mps_addr_t addr;
do {
die(mps_reserve(&addr, obj_ap, size), "Couldn't allocate.");
obj = addr;
obj->type = TYPE_REF;
obj->u.ref = NULL;
} while (!mps_commit(obj_ap, addr, size));
obj->u.ref = first;
first = obj;
}
pid = fork();
cdie(pid >= 0, "fork failed");
/* Allow a collection to start, which will cause a read barrier to
be applied to any segment containing live objects that was
scanned. */
mps_arena_release(arena);
/* Read all the objects, so that if there is read barrier in place
we will hit it. */
for (obj = first; obj != NULL; obj = obj->u.ref) {
Insist(obj->type == TYPE_REF);
}
mps_arena_park(arena);
if (pid != 0) {
/* Parent: wait for child and check that its exit status is zero. */
int stat;
cdie(pid == waitpid(pid, &stat, 0), "waitpid failed");
cdie(WIFEXITED(stat), "child did not exit normally");
cdie(WEXITSTATUS(stat) == 0, "child exited with nonzero status");
printf("%s: Conclusion: Failed to find any defects.\n", argv[0]);
}
mps_ap_destroy(obj_ap);
mps_pool_destroy(pool);
mps_fmt_destroy(obj_fmt);
mps_root_destroy(stack_root);
mps_thread_dereg(thread);
mps_arena_destroy(arena);
return 0;
}
/* C. COPYRIGHT AND LICENSE
*
* Copyright (C) 2018-2020 Ravenbrook Limited <https://www.ravenbrook.com/>.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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