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Rewrite brk() and sbrk()

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This change reduces the .bss memory requirement for all executables by
O(64kb). The brk system calls are now fully tested and figured out and
might be useful for tiny programs that only target System Five.
This commit is contained in:
Justine Tunney 2022-10-01 23:11:56 -07:00
parent bc8532688b
commit 5005f2e446
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GPG key ID: BE714B4575D6E328
23 changed files with 643 additions and 294 deletions
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91
test/libc/runtime/brk_test.c Normal file
View file

@ -0,0 +1,91 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or 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 "libc/calls/struct/rlimit.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/limits.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/rlimit.h"
#include "libc/testlib/subprocess.h"
#include "libc/testlib/testlib.h"
void SetUp(void) {
if (IsWindows()) {
ASSERT_SYS(ENOSYS, -1, brk(0));
ASSERT_SYS(ENOSYS, MAP_FAILED, sbrk(0));
exit(0);
}
}
TEST(sbrk, testReportCurrentBreak) {
ASSERT_SYS(0, _end, sbrk(0));
}
TEST(sbrk, hugeDelta_returnsEoverflow) {
ASSERT_SYS(EOVERFLOW, MAP_FAILED, sbrk(INTPTR_MAX));
}
TEST(brk, underflowsEnd_returnsEinval) {
ASSERT_SYS(EINVAL, -1, brk(0));
}
TEST(sbrk, underflowsEnd_returnsEinval) {
ASSERT_SYS(EINVAL, MAP_FAILED, sbrk(-PAGESIZE));
}
TEST(sbrk, giantDelta_returnsEnomem) {
if (IsXnu()) return; // mmap polyfills this but brk doesn't right now
SPAWN(fork);
struct rlimit rl = {1024 * 1024, 1024 * 1024};
ASSERT_SYS(0, 0, setrlimit(RLIMIT_AS, &rl));
ASSERT_SYS(ENOMEM, MAP_FAILED, sbrk(1024 * 1024 * 4));
EXITS(0);
}
TEST(sbrk, overlapsExistingMapping_failsWithEexist) {
char *p = (char *)ROUNDUP((intptr_t)_end, FRAMESIZE);
ASSERT_EQ(p, mmap(p, FRAMESIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0));
ASSERT_SYS(EEXIST, MAP_FAILED, sbrk(FRAMESIZE));
ASSERT_SYS(0, 0, munmap(p, FRAMESIZE));
}
TEST(sbrk, testGrowAndShrink) {
SPAWN(fork);
ASSERT_FALSE(testlib_memoryexists(_end));
ASSERT_SYS(0, _end, sbrk(PAGESIZE));
ASSERT_SYS(0, _end + PAGESIZE, sbrk(0));
ASSERT_TRUE(testlib_memoryexists(_end));
ASSERT_FALSE(testlib_memoryexists(_end + PAGESIZE));
ASSERT_SYS(0, _end + PAGESIZE, sbrk(-PAGESIZE));
ASSERT_FALSE(testlib_memoryexists(_end));
EXITS(0);
}
TEST(brk, testGrowAndShrink) {
SPAWN(fork);
ASSERT_FALSE(testlib_memoryexists(_end));
ASSERT_EQ(0, brk(_end + PAGESIZE));
ASSERT_TRUE(testlib_memoryexists(_end));
ASSERT_FALSE(testlib_memoryexists(_end + PAGESIZE));
ASSERT_EQ(0, brk(_end));
EXITS(0);
}

153
test/libc/runtime/munmap_test.c
View file

@ -17,54 +17,21 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/siginfo.h"
#include "libc/calls/ucontext.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/atomic.h"
#include "libc/runtime/memtrack.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/sa.h"
#include "libc/testlib/testlib.h"
#include "third_party/xed/x86.h"
volatile int gotsignal;
char testlib_enable_tmp_setup_teardown;
void ContinueOnError(int sig, siginfo_t *si, void *vctx) {
struct XedDecodedInst xedd;
struct ucontext *ctx = vctx;
xed_decoded_inst_zero_set_mode(&xedd, XED_MACHINE_MODE_LONG_64);
xed_instruction_length_decode(&xedd, (void *)ctx->uc_mcontext.rip, 15);
ctx->uc_mcontext.rip += xedd.length;
gotsignal = sig;
}
noasan bool MemoryExists(char *p) {
volatile char c;
struct sigaction old[2];
struct sigaction sa = {
.sa_sigaction = ContinueOnError,
.sa_flags = SA_SIGINFO,
};
gotsignal = 0;
sigaction(SIGSEGV, &sa, old + 0);
sigaction(SIGBUS, &sa, old + 1);
c = atomic_load(p);
sigaction(SIGBUS, old + 1, 0);
sigaction(SIGSEGV, old + 0, 0);
return !gotsignal;
}
TEST(munmap, doesntExist_doesntCare) {
EXPECT_SYS(0, 0, munmap(0, FRAMESIZE * 8));
if (IsAsan()) {
// make sure it didn't unmap the null pointer shadow memory
EXPECT_TRUE(MemoryExists((char *)0x7fff8000));
EXPECT_TRUE(testlib_memoryexists((char *)0x7fff8000));
}
}
@ -78,27 +45,27 @@ TEST(munmap, test) {
char *p;
ASSERT_NE(MAP_FAILED, (p = mmap(0, FRAMESIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
EXPECT_TRUE(MemoryExists(p));
EXPECT_TRUE(testlib_memoryexists(p));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE));
EXPECT_FALSE(MemoryExists(p));
EXPECT_FALSE(testlib_memoryexists(p));
}
TEST(munmap, punchHoleInMemory) {
char *p;
ASSERT_NE(MAP_FAILED, (p = mmap(0, FRAMESIZE * 3, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 2));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 2));
EXPECT_SYS(0, 0, munmap(p + FRAMESIZE, FRAMESIZE));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 2));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 2));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE));
EXPECT_SYS(0, 0, munmap(p + FRAMESIZE * 2, FRAMESIZE));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 2));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 2));
}
TEST(munmap, memoryHasHole) {
@ -106,59 +73,59 @@ TEST(munmap, memoryHasHole) {
ASSERT_NE(MAP_FAILED, (p = mmap(0, FRAMESIZE * 3, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
EXPECT_SYS(0, 0, munmap(p + FRAMESIZE, FRAMESIZE));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 2));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 2));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE * 3));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 2));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 2));
}
TEST(munmap, blanketFree) {
char *p;
ASSERT_NE(MAP_FAILED, (p = mmap(0, FRAMESIZE * 3, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 2));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 2));
EXPECT_SYS(0, 0, munmap(p + FRAMESIZE * 0, FRAMESIZE));
EXPECT_SYS(0, 0, munmap(p + FRAMESIZE * 2, FRAMESIZE));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 2));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 2));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE * 3));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 2));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 2));
}
TEST(munmap, trimLeft) {
char *p;
ASSERT_NE(MAP_FAILED, (p = mmap(0, FRAMESIZE * 2, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE * 2));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 1));
}
TEST(munmap, trimRight) {
char *p;
ASSERT_NE(MAP_FAILED, (p = mmap(0, FRAMESIZE * 2, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_SYS(0, 0, munmap(p + FRAMESIZE, FRAMESIZE));
EXPECT_TRUE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_TRUE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 1));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE * 2));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 0));
EXPECT_FALSE(MemoryExists(p + FRAMESIZE * 1));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 0));
EXPECT_FALSE(testlib_memoryexists(p + FRAMESIZE * 1));
}
TEST(munmap, memoryGone) {
@ -174,9 +141,9 @@ TEST(munmap, testTooSmallToUnmapAsan) {
char *p;
ASSERT_NE(MAP_FAILED, (p = mmap(0, FRAMESIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
EXPECT_TRUE(MemoryExists((char *)(((intptr_t)p >> 3) + 0x7fff8000)));
EXPECT_TRUE(testlib_memoryexists((char *)(((intptr_t)p >> 3) + 0x7fff8000)));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE));
EXPECT_TRUE(MemoryExists((char *)(((intptr_t)p >> 3) + 0x7fff8000)));
EXPECT_TRUE(testlib_memoryexists((char *)(((intptr_t)p >> 3) + 0x7fff8000)));
}
TEST(munmap, testLargeEnoughToUnmapAsan) {
@ -195,7 +162,7 @@ TEST(munmap, testLargeEnoughToUnmapAsan) {
EXPECT_SYS(0, 0, munmap(p, n));
#if 0
EXPECT_FALSE(
MemoryExists((char *)(((intptr_t)(p + n / 2) >> 3) + 0x7fff8000)));
testlib_memoryexists((char *)(((intptr_t)(p + n / 2) >> 3) + 0x7fff8000)));
#endif
}
@ -207,12 +174,12 @@ TEST(munmap, tinyFile_roundupUnmapSize) {
ASSERT_SYS(0, 3, open("doge", O_RDONLY));
ASSERT_NE(MAP_FAILED, (p = mmap(0, 5, PROT_READ, MAP_PRIVATE, 3, 0)));
ASSERT_SYS(0, 0, close(3));
EXPECT_TRUE(MemoryExists(p));
EXPECT_TRUE(testlib_memoryexists(p));
// some kernels/versions support this, some don't
EXPECT_FALSE(MemoryExists(p + PAGESIZE));
EXPECT_FALSE(testlib_memoryexists(p + PAGESIZE));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE));
EXPECT_FALSE(MemoryExists(p));
EXPECT_FALSE(MemoryExists(p + 5));
EXPECT_FALSE(testlib_memoryexists(p));
EXPECT_FALSE(testlib_memoryexists(p + 5));
}
TEST(munmap, tinyFile_preciseUnmapSize) {
@ -224,13 +191,13 @@ TEST(munmap, tinyFile_preciseUnmapSize) {
ASSERT_NE(MAP_FAILED, (p = mmap(0, 5, PROT_READ, MAP_PRIVATE, 3, 0)));
ASSERT_NE(MAP_FAILED, (q = mmap(0, 5, PROT_READ, MAP_PRIVATE, 3, 0)));
ASSERT_SYS(0, 0, close(3));
EXPECT_TRUE(MemoryExists(p));
EXPECT_TRUE(MemoryExists(q));
EXPECT_TRUE(testlib_memoryexists(p));
EXPECT_TRUE(testlib_memoryexists(q));
EXPECT_SYS(0, 0, munmap(p, 5));
EXPECT_FALSE(MemoryExists(p));
EXPECT_TRUE(MemoryExists(q));
EXPECT_FALSE(testlib_memoryexists(p));
EXPECT_TRUE(testlib_memoryexists(q));
EXPECT_SYS(0, 0, munmap(q, 5));
EXPECT_FALSE(MemoryExists(q));
EXPECT_FALSE(testlib_memoryexists(q));
}
// clang-format off
@ -242,14 +209,14 @@ TEST(munmap, tinyFile_mapThriceUnmapOnce) {
ASSERT_NE(MAP_FAILED, mmap(p+FRAMESIZE*1, 5, PROT_READ, MAP_PRIVATE|MAP_FIXED, 3, 0));
ASSERT_NE(MAP_FAILED, mmap(p+FRAMESIZE*3, 5, PROT_READ, MAP_PRIVATE|MAP_FIXED, 3, 0));
ASSERT_SYS(0, 0, close(3));
EXPECT_TRUE(MemoryExists(p+FRAMESIZE*0));
EXPECT_TRUE(MemoryExists(p+FRAMESIZE*1));
EXPECT_FALSE(MemoryExists(p+FRAMESIZE*2));
EXPECT_TRUE(MemoryExists(p+FRAMESIZE*3));
EXPECT_TRUE(testlib_memoryexists(p+FRAMESIZE*0));
EXPECT_TRUE(testlib_memoryexists(p+FRAMESIZE*1));
EXPECT_FALSE(testlib_memoryexists(p+FRAMESIZE*2));
EXPECT_TRUE(testlib_memoryexists(p+FRAMESIZE*3));
EXPECT_SYS(0, 0, munmap(p, FRAMESIZE*5));
EXPECT_FALSE(MemoryExists(p+FRAMESIZE*0));
EXPECT_FALSE(MemoryExists(p+FRAMESIZE*1));
EXPECT_FALSE(MemoryExists(p+FRAMESIZE*2));
EXPECT_FALSE(MemoryExists(p+FRAMESIZE*3));
EXPECT_FALSE(testlib_memoryexists(p+FRAMESIZE*0));
EXPECT_FALSE(testlib_memoryexists(p+FRAMESIZE*1));
EXPECT_FALSE(testlib_memoryexists(p+FRAMESIZE*2));
EXPECT_FALSE(testlib_memoryexists(p+FRAMESIZE*3));
}
// clang-format on