mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-14 10:18:02 +00:00
f7780de24b
Cosmopolitan now supports mremap(), which is only supported on Linux and NetBSD. First, it allows memory mappings to be relocated without copying them; this can dramatically speed up data structures like std::vector if the array size grows larger than 256kb. The mremap() system call is also 10x faster than munmap() when shrinking large memory mappings. There's now two functions, getpagesize() and getgransize() which help to write portable code that uses mmap(MAP_FIXED). Alternative sysconf() may be called with our new _SC_GRANSIZE. The madvise() system call now has a better wrapper with improved documentation.
395 lines
13 KiB
C
395 lines
13 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/calls/landlock.h"
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#include "libc/calls/pledge.h"
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#include "libc/calls/struct/dirent.h"
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#include "libc/calls/struct/stat.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/mem/gc.h"
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#include "libc/runtime/internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sock/sock.h"
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#include "libc/stdio/stdio.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/af.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/msync.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/sysv/consts/s.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/sysv/consts/sock.h"
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#include "libc/testlib/subprocess.h"
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#include "libc/testlib/testlib.h"
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#include "libc/thread/thread.h"
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#include "libc/x/x.h"
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#include "libc/x/xasprintf.h"
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#define EACCES_OR_ENOENT (IsOpenbsd() ? ENOENT : EACCES)
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struct stat st;
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bool HasUnveilSupport(void) {
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return unveil("", 0) >= 0;
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}
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bool UnveilCanSecureTruncate(void) {
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int abi = unveil("", 0);
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return abi == 0 || abi >= 3;
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}
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void SetUpOnce(void) {
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if (!HasUnveilSupport()) {
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fprintf(stderr, "warning: unveil() not supported on this system: %m\n");
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exit(0);
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}
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testlib_enable_tmp_setup_teardown();
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}
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void SetUp(void) {
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// make sure zipos maps executable into memory early
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ASSERT_SYS(0, 0, stat("/zip/life.elf", &st));
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}
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TEST(unveil, api_differences) {
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("foo", 0755));
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ASSERT_SYS(0, 0, unveil("foo", "r"));
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if (IsOpenbsd()) {
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// openbsd imposes restrictions immediately
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ASSERT_SYS(ENOENT, -1, open("/", O_RDONLY | O_DIRECTORY));
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} else {
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// restrictions on linux don't go into effect until unveil(0,0)
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ASSERT_SYS(0, 3, open(".", O_RDONLY | O_DIRECTORY));
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ASSERT_SYS(0, 0, close(3));
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}
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ASSERT_SYS(0, 0, unveil(0, 0));
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// error numbers are inconsistent
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open("/", O_RDONLY | O_DIRECTORY));
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// wut
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if (IsLinux()) {
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ASSERT_SYS(0, 3, open("/", O_PATH)); // wut
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ASSERT_SYS(0, 0, stat("/", &st)); // wut
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}
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EXITS(0);
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}
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TEST(unveil, rx_readOnlyPreexistingExecutable_worksFine) {
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if (IsOpenbsd())
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return; // TOOD(jart): why pledge violation?
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("folder", 0755));
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testlib_extract("/zip/life.elf", "folder/life.elf", 0755);
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ASSERT_SYS(0, 0, unveil("folder", "rx"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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SPAWN(fork);
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execl("folder/life.elf", "folder/life.elf", 0);
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kprintf("execve failed! %s\n", strerror(errno));
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_Exit(127);
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EXITS(42);
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EXITS(0);
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}
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TEST(unveil, r_noExecutePreexistingExecutable_raisesEacces) {
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("folder", 0755));
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testlib_extract("/zip/life.elf", "folder/life.elf", 0755);
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ASSERT_SYS(0, 0, unveil("folder", "r"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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SPAWN(fork);
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ASSERT_SYS(EACCES, -1, execl("folder/life.elf", "folder/life.elf", 0));
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EXITS(0);
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EXITS(0);
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}
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TEST(unveil, canBeUsedAgainAfterVfork) {
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ASSERT_SYS(0, 0, touch("bad", 0644));
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ASSERT_SYS(0, 0, touch("good", 0644));
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SPAWN(fork);
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SPAWN(vfork);
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ASSERT_SYS(0, 0, unveil("bad", "r"));
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ASSERT_SYS(0, 0, unveil("good", "r"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(0, 3, open("bad", 0));
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EXITS(0);
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ASSERT_SYS(0, 0, unveil("good", "r"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(0, 3, open("good", 0));
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open("bad", 0));
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EXITS(0);
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}
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TEST(unveil, rwc_createExecutableFile_isAllowedButCantBeRun) {
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("folder", 0755));
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ASSERT_SYS(0, 0, unveil("folder", "rwc"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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testlib_extract("/zip/life.elf", "folder/life.elf", 0755);
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SPAWN(fork);
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ASSERT_SYS(0, 0, stat("folder/life.elf", &st));
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ASSERT_SYS(EACCES, -1, execl("folder/life.elf", "folder/life.elf", 0));
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EXITS(0);
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EXITS(0);
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}
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TEST(unveil, rwcx_createExecutableFile_canAlsoBeRun) {
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if (IsOpenbsd())
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return; // TOOD(jart): why pledge violation?
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("folder", 0755));
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ASSERT_SYS(0, 0, unveil("folder", "rwcx"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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testlib_extract("/zip/life.elf", "folder/life.elf", 0755);
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SPAWN(fork);
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ASSERT_SYS(0, 0, stat("folder/life.elf", &st));
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execl("folder/life.elf", "folder/life.elf", 0);
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kprintf("execve failed! %s\n", strerror(errno));
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_Exit(127);
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EXITS(42);
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EXITS(0);
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}
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TEST(unveil, dirfdHacking_doesntWork) {
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, mkdir("garden", 0755));
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ASSERT_SYS(0, 0, touch("garden/secret.txt", 0644));
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ASSERT_SYS(0, 3, open("garden", O_RDONLY | O_DIRECTORY));
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(EACCES_OR_ENOENT, -1, openat(3, "secret.txt", O_RDONLY));
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EXITS(0);
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}
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TEST(unveil, mostRestrictivePolicy) {
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if (IsOpenbsd())
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return; // openbsd behaves oddly; see docs
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, mkdir("garden", 0755));
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ASSERT_SYS(0, 0, touch("garden/secret.txt", 0644));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open("jail", O_RDONLY | O_DIRECTORY));
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
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EXITS(0);
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}
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TEST(unveil, overlappingDirectories_inconsistentBehavior) {
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SPAWN(fork);
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ASSERT_SYS(0, 0, makedirs("f1/f2", 0755));
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testlib_extract("/zip/life.elf", "f1/f2/life.elf", 0755);
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ASSERT_SYS(0, 0, unveil("f1", "x"));
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ASSERT_SYS(0, 0, unveil("f1/f2", "r"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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if (IsOpenbsd()) {
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// OpenBSD favors the most restrictive policy
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SPAWN(fork);
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ASSERT_SYS(0, 0, stat("f1/f2/life.elf", &st));
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ASSERT_SYS(EACCES, -1, execl("f1/f2/life.elf", "f1/f2/life.elf", 0));
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EXITS(0);
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} else {
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// Landlock (Linux) uses the union of policies
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//
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// TODO(jart): this test flakes on github actions. it reports an
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// exit code of 0! find out why this is happening...
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// so far it's happened to MODE=rel and MODE=tiny...
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//
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// SPAWN(fork);
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// ASSERT_SYS(0, 0, stat("f1/f2/life.elf", &st));
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// execl("f1/f2/life.elf", "f1/f2/life.elf", 0);
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// kprintf("execve failed! %s\n", strerror(errno));
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// _Exit(127);
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// EXITS(42);
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}
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EXITS(0);
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}
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TEST(unveil, usedTwice_allowedOnLinux) {
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if (IsOpenbsd())
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return;
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, xbarf("jail/ok.txt", "hello", 5));
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ASSERT_SYS(0, 0, mkdir("garden", 0755));
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ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
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ASSERT_SYS(0, 0, mkdir("heaven", 0755));
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ASSERT_SYS(0, 0, xbarf("heaven/verysecret.txt", "hello", 5));
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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ASSERT_SYS(0, 0, unveil("garden", "rw"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(0, 3, open("garden/secret.txt", O_RDONLY));
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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ASSERT_SYS(0, 0, unveil("heaven", "rw")); // not allowed, superset of parent
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(0, 4, open("jail/ok.txt", O_RDONLY));
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ASSERT_SYS(EACCES, -1, open("garden/secret.txt", O_RDONLY));
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ASSERT_SYS(EACCES, -1, open("heaven/verysecret.txt", O_RDONLY));
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EXITS(0);
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}
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TEST(unveil, truncate_isForbiddenBySeccomp) {
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, mkdir("garden", 0755));
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ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(!UnveilCanSecureTruncate() ? EPERM : EACCES_OR_ENOENT, -1,
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truncate("garden/secret.txt", 0));
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if (IsLinux()) {
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ASSERT_SYS(0, 0, stat("garden/secret.txt", &st));
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ASSERT_EQ(5, st.st_size);
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}
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EXITS(0);
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}
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TEST(unveil, ftruncate_isForbidden) {
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if (IsOpenbsd())
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return; // b/c O_PATH is a Linux thing
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, mkdir("garden", 0755));
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ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(0, 3, open("garden/secret.txt", O_PATH));
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ASSERT_SYS(EBADF, -1, ftruncate(3, 0));
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ASSERT_SYS(0, 0, close(3));
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ASSERT_SYS(0, 0, stat("garden/secret.txt", &st));
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ASSERT_EQ(5, st.st_size);
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EXITS(0);
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}
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TEST(unveil, procfs_isForbiddenByDefault) {
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if (IsOpenbsd())
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return;
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(EACCES, -1, open("/proc/self/cmdline", O_RDONLY));
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EXITS(0);
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}
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void *Worker(void *arg) {
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
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return 0;
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}
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TEST(unveil, isInheritedAcrossThreads) {
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pthread_t t;
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, mkdir("garden", 0755));
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ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(0, 0, pthread_create(&t, 0, Worker, 0));
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EXPECT_SYS(0, 0, pthread_join(t, 0));
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EXITS(0);
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}
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void *Worker2(void *arg) {
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
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return 0;
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}
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TEST(unveil, isThreadSpecificOnLinux_isProcessWideOnOpenbsd) {
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pthread_t t;
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, mkdir("garden", 0755));
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ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
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ASSERT_SYS(0, 0, pthread_create(&t, 0, Worker2, 0));
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EXPECT_SYS(0, 0, pthread_join(t, 0));
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if (IsOpenbsd()) {
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ASSERT_SYS(ENOENT, -1, open("garden/secret.txt", O_RDONLY));
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} else {
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ASSERT_SYS(0, 3, open("garden/secret.txt", O_RDONLY));
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}
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EXITS(0);
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}
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TEST(unveil, usedTwice_forbidden_worksWithPledge) {
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int ws, pid;
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bool *gotsome;
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ASSERT_NE(-1, (gotsome = _mapshared(getpagesize())));
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ASSERT_NE(-1, (pid = fork()));
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if (!pid) {
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__pledge_mode = PLEDGE_PENALTY_KILL_PROCESS;
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// install our first seccomp filter
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ASSERT_SYS(0, 0, pledge("stdio rpath wpath cpath unveil", 0));
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ASSERT_SYS(0, 0, mkdir("jail", 0755));
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ASSERT_SYS(0, 0, mkdir("garden", 0755));
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ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
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ASSERT_SYS(0, 0, unveil("jail", "rw"));
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// committing and locking causes a new bpf filter to be installed
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
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// verify the second filter is working
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
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// verify the first filter is still working
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*gotsome = true;
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socket(AF_UNIX, SOCK_STREAM, 0);
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_Exit(0);
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}
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ASSERT_NE(-1, wait(&ws));
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ASSERT_TRUE(*gotsome);
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ASSERT_TRUE(WIFSIGNALED(ws));
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ASSERT_EQ(IsOpenbsd() ? SIGABRT : SIGSYS, WTERMSIG(ws));
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EXPECT_SYS(0, 0, munmap(gotsome, getpagesize()));
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}
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TEST(unveil, lotsOfPaths) {
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int i, n;
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SPAWN(fork);
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n = 100;
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for (i = 0; i < n; ++i) {
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ASSERT_SYS(0, 0, touch(xasprintf("%d", i), 0644));
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ASSERT_SYS(0, 0, touch(xasprintf("%d-", i), 0644));
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}
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for (i = 0; i < n; ++i) {
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ASSERT_SYS(0, 0, unveil(xasprintf("%d", i), "rw"));
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}
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ASSERT_SYS(0, 0, unveil(0, 0));
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for (i = 0; i < n; ++i) {
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ASSERT_SYS(0, 3, open(xasprintf("%d", i), O_RDONLY));
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ASSERT_SYS(0, 0, close(3));
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ASSERT_SYS(EACCES_OR_ENOENT, -1, open(xasprintf("%d-", i), O_RDONLY));
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}
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EXITS(0);
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}
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TEST(unveil, reparent) {
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return; // need abi 2 :'(
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SPAWN(fork);
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ASSERT_SYS(0, 0, mkdir("x", 0755));
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ASSERT_SYS(0, 0, unveil("x", "rwc"));
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ASSERT_SYS(0, 0, unveil(0, 0));
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ASSERT_SYS(0, 0, mkdir("x/y", 0755));
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ASSERT_SYS(0, 0, touch("x/y/z", 0644));
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ASSERT_SYS(0, 0, rename("x/y/z", "x/z"));
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EXITS(0);
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}
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