Make mmap() work better

- Mapping file offsets now works on Windows
- Mapping stack memory now works on OpenBSD

libc/calls/open-nt.c

@@ -42,16 +42,7 @@ static textwindows int64_t open$nt$impl(int dirfd, const char *path,
   char16_t path16[PATH_MAX];
   if (__mkntpathat(dirfd, path, flags, path16) == -1) return -1;
   if ((handle = CreateFile(
-           path16,
+           path16, flags & 0xf000000f, /* see consts.sh */
-           (flags & 0xf000000f) |
-               (/* this is needed if we mmap(rwx+cow)
-                   nt is choosy about open() access */
-                (flags & O_APPEND)
-                    ? kNtFileAppendData
-                    : (flags & O_ACCMODE) == O_RDONLY
-                          ? kNtGenericExecute | kNtFileGenericRead
-                          : kNtGenericExecute | kNtFileGenericRead |
-                                kNtFileGenericWrite),
            (flags & O_EXCL)
                ? kNtFileShareExclusive
                : kNtFileShareRead | kNtFileShareWrite | kNtFileShareDelete,
@@ -75,14 +66,6 @@ static textwindows int64_t open$nt$impl(int dirfd, const char *path,
                        kNtFileFlagBackupSemantics | kNtFileFlagPosixSemantics |
                        kNtFileAttributeTemporary)))),
            0)) != -1) {
-    if (flags & O_SPARSE) {
-      /*
-       * TODO(jart): Can all files be sparse files? That seems to be the
-       *             way Linux behaves out of the box.
-       * TODO(jart): Wow why does sparse wreak havoc?
-       */
-      DeviceIoControl(handle, kNtFsctlSetSparse, NULL, 0, NULL, 0, &br, NULL);
-    }
     return handle;
   } else if (GetLastError() == kNtErrorFileExists &&
              ((flags & O_CREAT) &&

libc/runtime/directmapnt.c

@@ -16,6 +16,7 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
 #include "libc/nt/enum/filemapflags.h"
 #include "libc/nt/enum/pageflags.h"
@@ -30,7 +31,8 @@ textwindows struct DirectMap __mmap$nt(void *addr, size_t size, unsigned prot,
   if ((dm.maphandle = CreateFileMappingNuma(
            handle, &kNtIsInheritable,
            (prot & PROT_WRITE) ? kNtPageExecuteReadwrite : kNtPageExecuteRead,
-           size >> 32, size, NULL, kNtNumaNoPreferredNode))) {
+           handle != -1 ? 0 : size >> 32, handle != -1 ? 0 : size, NULL,
+           kNtNumaNoPreferredNode))) {
     if (!(dm.addr = MapViewOfFileExNuma(
               dm.maphandle,
               (prot & PROT_WRITE)

libc/runtime/mmap.c

@@ -52,13 +52,14 @@
  * @param flags can have MAP_ANONYMOUS, MAP_SHARED, MAP_PRIVATE, etc.
  * @param fd is an open()'d file descriptor whose contents shall be
  *     mapped, and is ignored if MAP_ANONYMOUS is specified
- * @param offset specifies absolute byte index of fd's file for mapping,
+ * @param off specifies absolute byte index of fd's file for mapping,
- *     and should be zero if MAP_ANONYMOUS is specified
+ *     should be zero if MAP_ANONYMOUS is specified, and sadly needs
+ *     to be 64kb aligned too
  * @return virtual base address of new mapping, or MAP_FAILED w/ errno
  */
 void *mmap(void *addr, size_t size, int prot, int flags, int fd, int64_t off) {
-  int i, x, n, a, b;
   struct DirectMap dm;
+  int i, x, n, a, b, f;
   if (!size) return VIP(einval());
   if (!ALIGNED(off)) return VIP(einval());
   if (!ALIGNED(addr)) return VIP(einval());
@@ -84,7 +85,12 @@ void *mmap(void *addr, size_t size, int prot, int flags, int fd, int64_t off) {
     }
     addr = (void *)(intptr_t)((int64_t)x << 16);
   }
-  dm = __mmap(addr, size, prot, flags | MAP_FIXED, fd, off);
+  f = flags | MAP_FIXED;
+  if (IsOpenbsd() && (f & MAP_GROWSDOWN)) { /* openbsd:dubstack */
+    dm = __mmap(addr, size, prot, f & ~MAP_GROWSDOWN, fd, off);
+    if (dm.addr == MAP_FAILED) return MAP_FAILED;
+  }
+  dm = __mmap(addr, size, prot, f, fd, off);
   if (dm.addr == MAP_FAILED || dm.addr != addr) {
     return MAP_FAILED;
   }

libc/sysv/consts.sh

@@ -205,10 +205,10 @@ syscon	sig	SIGRTMIN				0			0			65			0			0
 #																			  │││  │ ┌┴───dwDesiredAccess
 #																			N │││  │ │
 #	group	name					GNU/Systemd		XNU's Not UNIX		FreeBSD			OpenBSD			T │││┌─┴┐│		Commentary
-syscon	open	O_RDONLY				0			0			0			0			0x80000000		# unix consensus & kNtGenericRead
+syscon	open	O_RDONLY				0			0			0			0			0xA0000000		# unix consensus & kNtGenericRead|kNtGenericExecute
 syscon	open	O_WRONLY				1			1			1			1			0x40000000		# unix consensus & kNtGenericWrite
-syscon	open	O_RDWR					2			2			2			2			0xc0000000		# unix consensus & kNtGenericRead|kNtGenericWrite
+syscon	open	O_RDWR					2			2			2			2			0xE0000000		# unix consensus & kNtGenericRead|kNtGenericWrite|kNtGenericExecute
-syscon	open	O_ACCMODE				3			3			3			3			0xc0000000		# O_RDONLY|O_WRONLY|O_RDWR
+syscon	open	O_ACCMODE				3			3			3			3			0xE0000000		# O_RDONLY|O_WRONLY|O_RDWR
 syscon	open	O_APPEND				0x0400			8			8			8			0x00000004		# bsd consensus & kNtFileAppendData; won't pose issues w/ mknod(S_IFIFO)
 syscon	open	O_CREAT					0x40			0x0200			0x0200			0x0200			0x00000040		# bsd consensus & NT faked as Linux
 syscon	open	O_EXCL					0x80			0x0800			0x0800			0x0800			0x00000080		# bsd consensus & NT faked as Linux

libc/sysv/consts/O_ACCMODE.s

@@ -1,2 +1,2 @@
 .include "libc/sysv/consts/syscon.inc"
-.syscon open O_ACCMODE 3 3 3 3 0xc0000000
+.syscon open O_ACCMODE 3 3 3 3 0xE0000000

libc/sysv/consts/O_RDONLY.s

@@ -1,2 +1,2 @@
 .include "libc/sysv/consts/syscon.inc"
-.syscon open O_RDONLY 0 0 0 0 0x80000000
+.syscon open O_RDONLY 0 0 0 0 0xA0000000

libc/sysv/consts/O_RDWR.s

@@ -1,2 +1,2 @@
 .include "libc/sysv/consts/syscon.inc"
-.syscon open O_RDWR 2 2 2 2 0xc0000000
+.syscon open O_RDWR 2 2 2 2 0xE0000000

test/libc/runtime/mmap_test.c

@@ -88,6 +88,42 @@ TEST(mmap, testMapFixed_destroysEverythingInItsPath) {
   EXPECT_NE(-1, munmap((void *)kFixedmapStart, FRAMESIZE * 3));
 }
 
+TEST(mmap, customStackMemory_isAuthorized) {
+  char *stack;
+  uintptr_t w, r;
+  ASSERT_NE(MAP_FAILED,
+            (stack = mmap(NULL, STACKSIZE, PROT_READ | PROT_WRITE,
+                          MAP_ANONYMOUS | MAP_PRIVATE | MAP_GROWSDOWN, -1, 0)));
+  asm("mov\t%%rsp,%0\n\t"
+      "mov\t%2,%%rsp\n\t"
+      "push\t%3\n\t"
+      "pop\t%1\n\t"
+      "mov\t%0,%%rsp"
+      : "=&r"(w), "=&r"(r)
+      : "rm"(stack + STACKSIZE - 8), "i"(123));
+  ASSERT_EQ(123, r);
+}
+
+TEST(mmap, fileOffset) {
+  int fd;
+  char *map;
+  char testdir[PATH_MAX];
+  sprintf(testdir, "o/tmp/%s.%d", program_invocation_short_name, getpid());
+  ASSERT_NE(-1, makedirs(testdir, 0755));
+  ASSERT_NE(-1, chdir(testdir));
+  ASSERT_NE(-1, (fd = open("foo", O_CREAT | O_RDWR, 0644)));
+  EXPECT_NE(-1, ftruncate(fd, FRAMESIZE * 2));
+  EXPECT_NE(-1, pwrite(fd, "hello", 5, FRAMESIZE * 0));
+  EXPECT_NE(-1, pwrite(fd, "there", 5, FRAMESIZE * 1));
+  ASSERT_NE(MAP_FAILED, (map = mmap(NULL, FRAMESIZE, PROT_READ, MAP_PRIVATE, fd,
+                                    FRAMESIZE)));
+  EXPECT_EQ(0, memcmp(map, "there", 5), "%#.*s", 5, map);
+  EXPECT_NE(-1, munmap(map, FRAMESIZE));
+  EXPECT_NE(-1, close(fd));
+  ASSERT_NE(-1, chdir("../../.."));
+  ASSERT_NE(-1, rmrf(testdir));
+}
+
 TEST(isheap, nullPtr) {
   ASSERT_FALSE(isheap(NULL));
 }

third_party/chibicc/test/test.mk

@@ -21,13 +21,8 @@ THIRD_PARTY_CHIBICC_TEST_HDRS = $(filter %.h,$(THIRD_PARTY_CHIBICC_TEST_FILES))
 THIRD_PARTY_CHIBICC_TEST_TESTS = $(THIRD_PARTY_CHIBICC_TEST_COMS:%=%.ok)
 
 THIRD_PARTY_CHIBICC_TEST_COMS =							\
-	$(THIRD_PARTY_CHIBICC_TEST_SRCS_TEST:%.c=o/$(MODE)/%.com)
+	$(THIRD_PARTY_CHIBICC_TEST_SRCS_TEST:%_test.c=o/$(MODE)/%_test.com)	\
-
+	$(THIRD_PARTY_CHIBICC_TEST_SRCS_TEST:%_test.c=o/$(MODE)/%_test2.com)
-# TODO(jart): make chibicc compiled chibicc work with asan runtime
-ifneq ($(MODE),dbg)
-THIRD_PARTY_CHIBICC_TEST_COMS +=						\
-	$(THIRD_PARTY_CHIBICC_TEST_SRCS_TEST:%.c=o/$(MODE)/%2.com)
-endif
 
 THIRD_PARTY_CHIBICC_TEST_OBJS =							\
 	$(THIRD_PARTY_CHIBICC_TEST_SRCS:%.c=o/$(MODE)/%.chibicc.o)
@@ -62,21 +57,19 @@ THIRD_PARTY_CHIBICC_TEST_DEPS :=						\
 	$(call uniq,$(foreach x,$(THIRD_PARTY_CHIBICC_TEST_DIRECTDEPS),$($(x))))
 
 $(THIRD_PARTY_CHIBICC_TEST_A):							\
-		third_party/chibicc/test/					\
 		$(THIRD_PARTY_CHIBICC_TEST_A).pkg				\
-		$(THIRD_PARTY_CHIBICC_TEST_OBJS)
+		o/$(MODE)/third_party/chibicc/test/common.chibicc.o
 
 $(THIRD_PARTY_CHIBICC_TEST2_A):							\
-		third_party/chibicc/test/					\
 		$(THIRD_PARTY_CHIBICC_TEST2_A).pkg				\
-		$(THIRD_PARTY_CHIBICC_TEST2_OBJS)
+		o/$(MODE)/third_party/chibicc/test/common.chibicc2.o
 
 $(THIRD_PARTY_CHIBICC_TEST_A).pkg:						\
-		$(THIRD_PARTY_CHIBICC_TEST_OBJS)				\
+		o/$(MODE)/third_party/chibicc/test/common.chibicc.o		\
 		$(foreach x,$(THIRD_PARTY_CHIBICC_TEST_DIRECTDEPS),$($(x)_A).pkg)
 
 $(THIRD_PARTY_CHIBICC_TEST2_A).pkg:						\
-		$(THIRD_PARTY_CHIBICC_TEST2_OBJS)				\
+		o/$(MODE)/third_party/chibicc/test/common.chibicc2.o		\
 		$(foreach x,$(THIRD_PARTY_CHIBICC_TEST_DIRECTDEPS),$($(x)_A).pkg)
 
 o/$(MODE)/third_party/chibicc/test/%.com.dbg:					\

third_party/chibicc/tokenize.c

@@ -136,21 +136,16 @@ static int read_ident(char *start) {
   }
 }
 
-static int from_hex(char c) {
-  if ('0' <= c && c <= '9') return c - '0';
-  if ('a' <= c && c <= 'f') return c - 'a' + 10;
-  return c - 'A' + 10;
-}
-
 // Read a punctuator token from p and returns its length.
 int read_punct(char *p) {
-  static char kw[][4] = {"<<=", ">>=", "...", "==", "!=", "<=", ">=", "->",
+  static const char kPunct[][4] = {
-                         "+=",  "-=",  "*=",  "/=", "++", "--", "%=", "&=",
+      "<<=", ">>=", "...", "==", "!=", "<=", ">=", "->", "+=", "-=", "*=", "/=",
-                         "|=",  "^=",  "&&",  "||", "<<", ">>", "##"};
+      "++",  "--",  "%=",  "&=", "|=", "^=", "&&", "||", "<<", ">>", "##",
-  for (int i = 0; i < sizeof(kw) / sizeof(*kw); i++) {
+  };
+  for (int i = 0; i < sizeof(kPunct) / sizeof(*kPunct); i++) {
     for (int j = 0;;) {
-      if (p[j] != kw[i][j]) break;
+      if (p[j] != kPunct[i][j]) break;
-      if (!kw[i][++j]) return j;
+      if (!kPunct[i][++j]) return j;
     }
   }
   return ispunct(*p) ? 1 : 0;
@@ -200,7 +195,7 @@ int read_escaped_char(char **new_pos, char *p) {
     if (!isxdigit(*p)) error_at(p, "invalid hex escape sequence");
     unsigned c = 0;
     for (; isxdigit(*p); p++) {
-      c = (c << 4) + from_hex(*p); /* TODO(jart): overflow here unicode_test */
+      c = (c << 4) + hextoint(*p); /* TODO(jart): overflow here unicode_test */
     }
     *new_pos = p;
     return c;
@@ -628,7 +623,7 @@ static uint32_t read_universal_char(char *p, int len) {
   uint32_t c = 0;
   for (int i = 0; i < len; i++) {
     if (!isxdigit(p[i])) return 0;
-    c = (c << 4) | from_hex(p[i]);
+    c = (c << 4) | hextoint(p[i]);
   }
   return c;
 }