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Improve signals and memory protection

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- Document sigaction()
- Simplify New Technology fork() code
- Testing and many bug fixes for mprotect()
- Distribute Intel Xed ILD in the amalgamation
- Turn Xed enums into defines to avoid DWARF bloat
- Improve polyfilling of SA_SIGINFO on BSDs and fix bugs
- setpgid(getpid(), getpid()) on Windows will ignore CTRL-C
- Work around issues relating to NT mappings being executable
- Permit automatic executable stack override via `ape_stack_pf`
This commit is contained in:
Justine Tunney 2022-04-12 22:11:00 -07:00
parent c95c9d9508
commit f684e348d4
76 changed files with 1844 additions and 1121 deletions
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66
test/libc/calls/mprotect_test.c
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@ -1,66 +0,0 @@
/*-*- 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 2021 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/calls.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/sa.h"
#include "libc/testlib/testlib.h"
jmp_buf jb;
bool gotsegv;
struct sigaction old[2];
void OnSigSegv(int sig) {
gotsegv = true;
longjmp(jb, 1);
}
void SetUp(void) {
sigaction(SIGBUS, NULL, &old[0]);
sigaction(SIGSEGV, NULL, &old[1]);
}
void TearDown(void) {
sigaction(SIGBUS, &old[0], NULL);
sigaction(SIGSEGV, &old[1], NULL);
}
TEST(mprotect, test) {
char *p = gc(memalign(PAGESIZE, PAGESIZE));
p[0] = 0;
ASSERT_NE(-1, mprotect(p, PAGESIZE, PROT_READ | PROT_WRITE));
p[0] = 1;
EXPECT_EQ(1, p[0]);
}
TEST(mprotect, testSegfault) {
char *p;
struct sigaction ss = {.sa_handler = OnSigSegv, .sa_flags = SA_NODEFER};
p = gc(memalign(PAGESIZE, PAGESIZE));
EXPECT_NE(-1, sigaction(SIGBUS, &ss, NULL));
EXPECT_NE(-1, sigaction(SIGSEGV, &ss, NULL));
if (!setjmp(jb)) p[0] = 1;
EXPECT_FALSE(gotsegv);
EXPECT_NE(-1, mprotect(p, sizeof(p), PROT_READ));
if (!setjmp(jb)) p[0] = 2;
EXPECT_TRUE(gotsegv);
EXPECT_EQ(1, p[0]);
EXPECT_NE(-1, mprotect(p, sizeof(p), PROT_READ | PROT_WRITE));
}

6
test/libc/calls/sigaction_test.c
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@ -124,11 +124,15 @@ TEST(sigaction, debugBreak_handlerCanReadCpuState) {
// test fpu crash (unrecoverable)
// test signal handler can modify cpu registers (now it's recoverable!)
void OnFpe(int sig, struct siginfo *si, struct ucontext *ctx) {
void SkipOverFaultingInstruction(struct ucontext *ctx) {
struct XedDecodedInst xedd;
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;
}
void OnFpe(int sig, struct siginfo *si, struct ucontext *ctx) {
SkipOverFaultingInstruction(ctx);
ctx->uc_mcontext.rax = 42;
ctx->uc_mcontext.rdx = 0;
}