Implement zipos mmap (#725)

libc/runtime/mmap.c

@@ -50,6 +50,7 @@
 #include "libc/sysv/consts/prot.h"
 #include "libc/sysv/errfuns.h"
 #include "libc/thread/thread.h"
+#include "libc/zipos/zipos.internal.h"
 
 #define MAP_ANONYMOUS_linux   0x00000020
 #define MAP_ANONYMOUS_openbsd 0x00001000
@@ -485,6 +486,11 @@ static noasan inline void *Mmap(void *addr, size_t size, int prot, int flags,
 void *mmap(void *addr, size_t size, int prot, int flags, int fd, int64_t off) {
   void *res;
   size_t toto;
+  if (__isfdkind(fd, kFdZip)) {
+    return _weaken(__zipos_mmap)(
+        addr, size, prot, flags,
+        (struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle, off);
+  }
 #if defined(SYSDEBUG) && (_KERNTRACE || _NTTRACE)
   if (IsWindows()) {
     STRACE("mmap(%p, %'zu, %s, %s, %d, %'ld) → ...", addr, size,

libc/zipos/mmap.c

@@ -0,0 +1,76 @@
+/*-*- 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 2023 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/iovec.h"
+#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/intrin/likely.h"
+#include "libc/intrin/strace.internal.h"
+#include "libc/sysv/consts/map.h"
+#include "libc/sysv/consts/prot.h"
+#include "libc/sysv/errfuns.h"
+#include "libc/zipos/zipos.internal.h"
+
+#define IP(X)  (intptr_t)(X)
+#define VIP(X) (void *)IP(X)
+
+/**
+ * Map zipos file into memory. See mmap.
+ *
+ * @param addr should be 0 or a compatible address
+ * @param size must be >0 and will be rounded up to FRAMESIZE
+ *     automatically.
+ * @param prot can have PROT_READ/PROT_WRITE/PROT_EXEC/PROT_NONE/etc.
+ * @param flags cannot have `MAP_SHARED` or `MAP_ANONYMOUS`, there is
+ *     no actual file backing for zipos files. `MAP_SHARED` could be
+ *     simulated for non-writable mappings, but that would require
+ *     tracking zipos mappings to prevent making it PROT_WRITE.
+ * @param h is a zip store object
+ * @param off specifies absolute byte index of h's file for mapping,
+ *     it does not need to be 64kb aligned.
+ * @return virtual base address of new mapping, or MAP_FAILED w/ errno
+ */
+void *__zipos_mmap(void *addr, size_t size, int prot, int flags,
+                   struct ZiposHandle *h, int64_t off) {
+  if (!(flags & MAP_PRIVATE) ||
+      (flags & ~(MAP_PRIVATE | MAP_FILE | MAP_FIXED | MAP_FIXED_NOREPLACE)) ||
+      (!!(flags & MAP_FIXED) ^ !!(flags & MAP_FIXED_NOREPLACE))) {
+    STRACE(
+        "zipos mappings currently only support MAP_PRIVATE with select flags");
+    return VIP(einval());
+  }
+
+  const int tempProt = !IsXnu() ? prot | PROT_WRITE : PROT_WRITE;
+  void *outAddr =
+      mmap(addr, size, tempProt, (flags & (~MAP_FILE)) | MAP_ANONYMOUS, -1, 0);
+  if (outAddr == MAP_FAILED) {
+    return MAP_FAILED;
+  }
+  const int64_t beforeOffset = __zipos_lseek(h, 0, SEEK_CUR);
+  if ((beforeOffset == -1) ||
+      (__zipos_read(h, &(struct iovec){outAddr, size}, 1, off) == -1) ||
+      (__zipos_lseek(h, beforeOffset, SEEK_SET) == -1) ||
+      ((prot != tempProt) && (mprotect(outAddr, size, prot) == -1))) {
+    const int e = errno;
+    munmap(outAddr, size);
+    errno = e;
+    return MAP_FAILED;
+  }
+  return outAddr;
+}

libc/zipos/open.c

@@ -48,7 +48,7 @@
 static char *mapend;
 static size_t maptotal;
 
-static void *__zipos_mmap(size_t mapsize) {
+static void *__zipos_mmap_space(size_t mapsize) {
   char *start;
   size_t offset;
   _unassert(mapsize);
@@ -78,7 +78,7 @@ StartOver:
     ph = &h->next;
   }
   if (!h) {
-    h = __zipos_mmap(mapsize);
+    h = __zipos_mmap_space(mapsize);
   }
   __zipos_unlock();
   if (IsAsan()) {

libc/zipos/zipos.S

@@ -34,6 +34,7 @@
 	.yoink	__zipos_read
 	.yoink	__zipos_stat
 	.yoink	__zipos_notat
+	.yoink	__zipos_mmap
 
 //	TODO(jart): why does corruption happen when zip has no assets?
 	.yoink	.cosmo

libc/zipos/zipos.internal.h

@@ -48,6 +48,8 @@ ssize_t __zipos_write(struct ZiposHandle *, const struct iovec *, size_t,
 int64_t __zipos_lseek(struct ZiposHandle *, int64_t, unsigned) _Hide;
 int __zipos_fcntl(int, int, uintptr_t) _Hide;
 int __zipos_notat(int, const char *) _Hide;
+void *__zipos_mmap(void *, uint64_t, int32_t, int32_t, struct ZiposHandle *,
+                   int64_t) _Hide;
 
 #ifdef _NOPL0
 #define __zipos_lock()   _NOPL0("__threadcalls", __zipos_lock)

test/libc/runtime/mmap_test.c

@@ -46,6 +46,8 @@
 #include "libc/x/xspawn.h"
 #include "third_party/xed/x86.h"
 
+STATIC_YOINK("zip_uri_support");
+
 char testlib_enable_tmp_setup_teardown;
 
 void SetUpOnce(void) {
@@ -219,6 +221,86 @@ TEST(isheap, mallocOffset) {
   ASSERT_TRUE(_isheap(p + 100000));
 }
 
+static const char *ziposLifePath = "/zip/life.elf";
+TEST(mmap, ziposCannotBeAnonymous) {
+  int fd;
+  void *p;
+  ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
+  EXPECT_SYS(EINVAL, MAP_FAILED,
+             (p = mmap(NULL, 0x00010000, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS,
+                       fd, 0)));
+  close(fd);
+}
+
+TEST(mmap, ziposCannotBeShared) {
+  int fd;
+  void *p;
+  ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
+  EXPECT_SYS(EINVAL, MAP_FAILED,
+             (p = mmap(NULL, 0x00010000, PROT_READ, MAP_SHARED, fd, 0)));
+  close(fd);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// zipos NON-SHARED READ-ONLY FILE MEMORY
+
+TEST(mmap, ziposCow) {
+  int fd;
+  void *p;
+  ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
+  EXPECT_NE(MAP_FAILED,
+            (p = mmap(NULL, 0x00010000, PROT_READ, MAP_PRIVATE, fd, 0)));
+  EXPECT_STREQN("ELF", ((const char *)p) + 1, 3);
+  EXPECT_NE(-1, munmap(p, 0x00010000));
+  EXPECT_NE(-1, close(fd));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// zipos NON-SHARED READ-ONLY FILE MEMORY BETWEEN PROCESSES
+
+TEST(mmap, ziposCowFileMapReadonlyFork) {
+  int fd, ws;
+  void *p;
+  ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
+  EXPECT_NE(MAP_FAILED, (p = mmap(NULL, 4, PROT_READ, MAP_PRIVATE, fd, 0)));
+  EXPECT_STREQN("ELF", ((const char *)p) + 1, 3);
+  ASSERT_NE(-1, (ws = xspawn(0)));
+  if (ws == -2) {
+    ASSERT_STREQN("ELF", ((const char *)p) + 1, 3);
+    _exit(0);
+  }
+  EXPECT_EQ(0, ws);
+  EXPECT_STREQN("ELF", ((const char *)p) + 1, 3);
+  EXPECT_NE(-1, munmap(p, 6));
+  EXPECT_NE(-1, close(fd));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// zipos NON-SHARED READ/WRITE FILE MEMORY BETWEEN PROCESSES
+
+TEST(mmap, ziposCowFileMapFork) {
+  int fd, ws;
+  void *p;
+  char lol[4];
+  ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
+  EXPECT_NE(MAP_FAILED,
+            (p = mmap(NULL, 6, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0)));
+  memcpy(p, "parnt", 6);
+  ASSERT_NE(-1, (ws = xspawn(0)));
+  if (ws == -2) {
+    ASSERT_STREQN("parnt", p, 5);
+    strcpy(p, "child");
+    ASSERT_STREQN("child", p, 5);
+    _exit(0);
+  }
+  EXPECT_EQ(0, ws);
+  EXPECT_STREQN("parnt", p, 5);  // child changing memory did not change parent
+  EXPECT_EQ(4, pread(fd, lol, 4, 0));
+  EXPECT_STREQN("ELF", &lol[1], 3);  // changing memory did not change file
+  EXPECT_NE(-1, munmap(p, 6));
+  EXPECT_NE(-1, close(fd));
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // NON-SHARED READ-ONLY FILE MEMORY
 
@@ -231,8 +313,7 @@ TEST(mmap, cow) {
             path);
   EXPECT_EQ(5, write(fd, "hello", 5));
   EXPECT_NE(-1, fdatasync(fd));
-  EXPECT_NE(MAP_FAILED,
-            (p = mmap(NULL, 5, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0)));
+  EXPECT_NE(MAP_FAILED, (p = mmap(NULL, 5, PROT_READ, MAP_PRIVATE, fd, 0)));
   EXPECT_STREQN("hello", p, 5);
   EXPECT_NE(-1, munmap(p, 5));
   EXPECT_NE(-1, close(fd));
@@ -258,6 +339,7 @@ TEST(mmap, cowFileMapReadonlyFork) {
     ASSERT_STREQN("hello", p, 5);
     _exit(0);
   }
+  EXPECT_EQ(0, ws);
   EXPECT_STREQN("hello", p, 5);
   EXPECT_NE(-1, munmap(p, 6));
   EXPECT_NE(-1, close(fd));
@@ -285,6 +367,7 @@ TEST(mmap, cowFileMapFork) {
     ASSERT_STREQN("child", p, 5);
     _exit(0);
   }
+  EXPECT_EQ(0, ws);
   EXPECT_STREQN("parnt", p, 5);  // child changing memory did not change parent
   EXPECT_EQ(6, pread(fd, lol, 6, 0));
   EXPECT_STREQN("parnt", lol, 5);  // changing memory did not change file
@@ -310,6 +393,7 @@ TEST(mmap, sharedAnonMapFork) {
     ASSERT_STREQN("child", p, 5);
     _exit(0);
   }
+  EXPECT_EQ(0, ws);
   EXPECT_STREQN("child", p, 5);  // boom
   EXPECT_NE(-1, munmap(p, 5));
 }
@@ -336,6 +420,7 @@ TEST(mmap, sharedFileMapFork) {
     ASSERT_NE(-1, msync(p, 6, MS_SYNC | MS_INVALIDATE));
     _exit(0);
   }
+  EXPECT_EQ(0, ws);
   EXPECT_STREQN("child", p, 5);  // child changing memory changed parent memory
   // XXX: RHEL5 has a weird issue where if we read the file into its own
   //      shared memory then corruption occurs!

test/libc/runtime/test.mk

@@ -51,6 +51,7 @@ o/$(MODE)/test/libc/runtime/runtime.pkg:			\
 
 o/$(MODE)/test/libc/runtime/%.com.dbg:				\
 		$(TEST_LIBC_RUNTIME_DEPS)			\
+		o/$(MODE)/test/libc/mem/prog/life.elf.zip.o			\
 		o/$(MODE)/test/libc/runtime/%.o			\
 		o/$(MODE)/test/libc/runtime/runtime.pkg		\
 		$(LIBC_TESTMAIN)				\