Write more runtime tests and fix bugs

This change adds tests for the new memory manager code particularly with
its windows support. Function call tracing now works reliably on Silicon
since our function hooker was missing new Apple self-modifying code APIs

Many tests that were disabled a long time ago on aarch64 are reactivated
by this change, now that arm support is on equal terms with x86. There's
been a lot of places where ftrace could cause deadlocks, which have been
hunted down across all platforms thanks to new tests. A bug in Windows's
kill() function has been identified.

libc/intrin/mmap.c

@@ -49,7 +49,7 @@
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
 
-#define MMDEBUG  1
+#define MMDEBUG  0
 #define MAX_SIZE 0x0ff800000000ul
 
 #define MAP_FIXED_NOREPLACE_linux 0x100000
@@ -94,8 +94,11 @@ privileged optimizespeed struct Map *__maps_floor(const char *addr) {
 }
 
 static bool __maps_overlaps(const char *addr, size_t size) {
-  struct Map *map, *floor = __maps_floor(addr);
-  for (map = floor; map && map->addr <= addr + size; map = __maps_next(map))
+  struct Map *map;
+  ASSERT(__maps_held());
+  if (!(map = __maps_floor(addr)))
+    map = __maps_first();
+  for (; map && map->addr <= addr + size; map = __maps_next(map))
     if (MAX(addr, map->addr) <
         MIN(addr + PGUP(size), map->addr + PGUP(map->size)))
       return true;
@@ -105,30 +108,33 @@ static bool __maps_overlaps(const char *addr, size_t size) {
 // returns true if all fragments of all allocations which overlap
 // [addr,addr+size) are completely contained by [addr,addr+size).
 textwindows static bool __maps_envelops(const char *addr, size_t size) {
-  struct Map *map, *next;
+  struct Map *map;
   size = PGUP(size);
+  ASSERT(__maps_held());
   if (!(map = __maps_floor(addr)))
-    if (!(map = __maps_first()))
-      return true;
-  do {
-    if (MAX(addr, map->addr) >= MIN(addr + size, map->addr + map->size))
-      break;  // didn't overlap mapping
-    if (!__maps_isalloc(map))
-      return false;  // didn't include first fragment of alloc
-    if (addr > map->addr)
-      return false;  // excluded leading pages of first fragment
-    // set map to last fragment in allocation
-    for (; (next = __maps_next(map)) && !__maps_isalloc(next); map = next)
-      // fragments within an allocation must be perfectly contiguous
-      ASSERT(map->addr + map->size == next->addr);
-    if (addr + size < map->addr + PGUP(map->size))
-      return false;  // excluded trailing pages of allocation
-  } while ((map = next));
+    map = __maps_first();
+  while (map && map->addr <= addr + size) {
+    if (MAX(addr, map->addr) < MIN(addr + size, map->addr + map->size)) {
+      if (!__maps_isalloc(map))
+        return false;  // didn't include first fragment of alloc
+      if (addr > map->addr)
+        return false;    // excluded leading pages of first fragment
+      struct Map *next;  // set map to last fragment in allocation
+      for (; (next = __maps_next(map)) && !__maps_isalloc(next); map = next)
+        ASSERT(map->addr + map->size == next->addr);  // contiguous
+      if (addr + size < map->addr + PGUP(map->size))
+        return false;  // excluded trailing pages of allocation
+      map = next;
+    } else {
+      map = __maps_next(map);
+    }
+  }
   return true;
 }
 
 void __maps_check(void) {
 #if MMDEBUG
+  ASSERT(__maps_held());
   size_t maps = 0;
   size_t pages = 0;
   static unsigned mono;
@@ -152,6 +158,22 @@ void __maps_check(void) {
 #endif
 }
 
+#if MMDEBUG
+static void __maps_ok(void) {
+  ASSERT(!__maps_reentrant());
+  __maps_lock();
+  __maps_check();
+  __maps_unlock();
+}
+__attribute__((__constructor__)) static void __maps_ctor(void) {
+  atexit(__maps_ok);
+  __maps_ok();
+}
+__attribute__((__destructor__)) static void __maps_dtor(void) {
+  __maps_ok();
+}
+#endif
+
 static int __muntrack(char *addr, size_t size, struct Map **deleted,
                       struct Map **untracked, struct Map temp[2]) {
   int rc = 0;
@@ -159,13 +181,14 @@ static int __muntrack(char *addr, size_t size, struct Map **deleted,
   struct Map *map;
   struct Map *next;
   size = PGUP(size);
+  ASSERT(__maps_held());
   if (!(map = __maps_floor(addr)))
     map = __maps_first();
   for (; map && map->addr <= addr + size; map = next) {
     next = __maps_next(map);
     char *map_addr = map->addr;
     size_t map_size = map->size;
-    if (!(MAX(addr, map_addr) < MIN(addr + size, map_addr + PGUP(map_size))))
+    if (MAX(addr, map_addr) >= MIN(addr + size, map_addr + PGUP(map_size)))
       continue;
     if (addr <= map_addr && addr + size >= map_addr + PGUP(map_size)) {
       if (map->hand == MAPS_RESERVATION)
@@ -350,6 +373,7 @@ static bool __maps_mergeable(const struct Map *x, const struct Map *y) {
 void __maps_insert(struct Map *map) {
   struct Map *left, *right;
   ASSERT(map->size);
+  ASSERT(__maps_held());
   ASSERT(!__maps_overlaps(map->addr, map->size));
   __maps.pages += (map->size + __pagesize - 1) / __pagesize;
 
@@ -460,7 +484,7 @@ static int __munmap(char *addr, size_t size) {
     return einval();
 
   // test for signal handler tragedy
-  if (__maps_held())
+  if (__maps_reentrant())
     return edeadlk();
 
   // lock the memory manager
@@ -469,8 +493,10 @@ static int __munmap(char *addr, size_t size) {
 
   // on windows we can only unmap whole allocations
   if (IsWindows())
-    if (!__maps_envelops(addr, size))
+    if (!__maps_envelops(addr, size)) {
+      __maps_unlock();
       return enotsup();
+    }
 
   // untrack mappings
   int rc;
@@ -500,6 +526,7 @@ void *__maps_randaddr(void) {
 }
 
 static void *__maps_pickaddr(size_t size) {
+  ASSERT(__maps_held());
   char *addr = 0;
   struct Map *map, *prev;
   size = GRUP(size);
@@ -569,11 +596,15 @@ static void *__mmap_impl(char *addr, size_t size, int prot, int flags, int fd,
       noreplace = true;
       sysflags |= MAP_FIXED_NOREPLACE_linux;
     } else if (IsFreebsd() || IsNetbsd()) {
+      // todo: insert a reservation like windows
       sysflags |= MAP_FIXED;
+      __maps_lock();
       if (__maps_overlaps(addr, size)) {
+        __maps_unlock();
         __maps_free(map);
         return (void *)eexist();
       }
+      __maps_unlock();
     } else {
       noreplace = true;
     }
@@ -729,7 +760,7 @@ static void *__mmap(char *addr, size_t size, int prot, int flags, int fd,
     return (void *)enomem();
 
   // test for signal handler reentry
-  if (__maps_held())
+  if (__maps_reentrant())
     return (void *)edeadlk();
 
   // create memory mappping
@@ -874,7 +905,7 @@ static void *__mremap(char *old_addr, size_t old_size, size_t new_size,
       return (void *)enomem();
 
   // test for signal handler reentry
-  if (__maps_held())
+  if (__maps_reentrant())
     return (void *)edeadlk();
 
   // lock the memory manager