Remove _Hide keyword

It never did anything and isn't worthwhile as documentation.

libc/runtime/__sigsetjmp_tail.c

@@ -23,7 +23,7 @@
 #ifdef __x86_64__
 
 // kudos rich felker for the brilliant design
-_Hide int __sigsetjmp_tail(sigjmp_buf jb, int rc) {
+int __sigsetjmp_tail(sigjmp_buf jb, int rc) {
   _Static_assert(
       sizeof(sigjmp_buf) == sizeof(jmp_buf) + 8 + 8 + sizeof(sigset_t),
       "please recompute sigjmp_buf w.r.t. sigset_t");

libc/runtime/enable_threads.c

@@ -17,12 +17,8 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "ape/sections.internal.h"
-#include "libc/assert.h"
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/sigset.h"
 #include "libc/calls/syscall-sysv.internal.h"
 #include "libc/intrin/strace.internal.h"
-#include "libc/runtime/morph.h"
 #include "libc/runtime/runtime.h"
 #include "libc/thread/tls.h"
 
@@ -30,8 +26,7 @@ extern int __threadcalls_end[] __attribute__((__weak__));
 extern int __threadcalls_start[] __attribute__((__weak__));
 
 static privileged dontinline void FixupLockNops(void) {
-  sigset_t mask;
-  __morph_begin(&mask);
+  __morph_begin();
   /*
    * _NOPL("__threadcalls", func)
    *
@@ -55,7 +50,7 @@ static privileged dontinline void FixupLockNops(void) {
     __executable_start[*p + 1] = 0x67;
     __executable_start[*p + 2] = 0xe8;
   }
-  __morph_end(&mask);
+  __morph_end();
 }
 
 void __enable_threads(void) {

libc/runtime/getsymbol.c

@@ -19,7 +19,7 @@
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/symbols.internal.h"
 
-extern _Hide struct SymbolTable *__symtab;
+extern struct SymbolTable *__symtab;
 
 /**
  * Returns low index into symbol table for address.

libc/runtime/getsymboltable.c

@@ -35,7 +35,7 @@
 STATIC_YOINK("__get_symbol");
 
 static pthread_spinlock_t g_lock;
-_Hide struct SymbolTable *__symtab;  // for kprintf
+struct SymbolTable *__symtab;  // for kprintf
 
 /**
  * Looks for `.symtab` in zip central directory.

libc/runtime/hook.greg.c

@@ -20,7 +20,7 @@
 #include "libc/calls/struct/sigset.h"
 #include "libc/limits.h"
 #include "libc/macros.internal.h"
-#include "libc/runtime/morph.h"
+#include "libc/runtime/runtime.h"
 #include "libc/runtime/symbols.internal.h"
 
 #ifdef __x86_64__
@@ -109,11 +109,10 @@ static privileged void HookFunction(code_t *func, void *dest) {
 privileged dontinstrument noasan int __hook(void *dest,
                                             struct SymbolTable *st) {
   long i;
-  sigset_t mask;
   code_t *p, *pe;
   intptr_t lowest;
   if (!st) return -1;
-  __morph_begin(&mask);
+  __morph_begin();
   lowest = MAX((intptr_t)__executable_start, (intptr_t)_ereal);
   for (i = 0; i < st->count; ++i) {
     if (st->symbols[i].x < 9) continue;
@@ -129,6 +128,6 @@ privileged dontinstrument noasan int __hook(void *dest,
       // kprintf("can't hook %t at %lx\n", p, p);
     }
   }
-  __morph_end(&mask);
+  __morph_end();
   return 0;
 }

libc/runtime/internal.h

@@ -31,25 +31,25 @@ extern unsigned char _tbss_offset[] __attribute__((__weak__));
 extern unsigned char _tls_size[] __attribute__((__weak__));
 extern unsigned char _tls_content[] __attribute__((__weak__));
 
-void _init(void) _Hide;
-int ftrace_init(void) _Hide;
-void ftrace_hook(void) _Hide;
-void __morph_tls(void) _Hide;
-void __enable_tls(void) _Hide;
-void __enable_threads(void) _Hide;
-void *__cxa_finalize(void *) _Hide;
+void _init(void);
+int ftrace_init(void);
+void ftrace_hook(void);
+void __morph_tls(void);
+void __enable_tls(void);
+void __enable_threads(void);
+void *__cxa_finalize(void *);
 void __stack_chk_fail(void) wontreturn relegated;
-void __stack_chk_fail_local(void) wontreturn relegated _Hide;
-void __asan_init(int, char **, char **, intptr_t *) _Hide;
-void _jmpstack(void *, void *, ...) _Hide wontreturn;
-long _setstack(void *, void *, ...) _Hide;
+void __stack_chk_fail_local(void) wontreturn relegated;
+void __asan_init(int, char **, char **, intptr_t *);
+void _jmpstack(void *, void *, ...) wontreturn;
+long _setstack(void *, void *, ...);
 int GetDosArgv(const char16_t *, char *, size_t, char **, size_t);
 int GetDosEnviron(const char16_t *, char *, size_t, char **, size_t);
 bool __intercept_flag(int *, char *[], const char *);
-int sys_mprotect_nt(void *, size_t, int) _Hide;
+int sys_mprotect_nt(void *, size_t, int);
 int __inflate(void *, size_t, const void *, size_t);
-noasan void *_Mmap(void *, size_t, int, int, int, int64_t) _Hide;
-noasan int _Munmap(char *, size_t) _Hide;
+noasan void *_Mmap(void *, size_t, int, int, int, int64_t);
+noasan int _Munmap(char *, size_t);
 void __on_arithmetic_overflow(void);
 void __init_fds(void);
 

libc/runtime/isdynamicexecutable.c

@@ -1,81 +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 2022 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/blockcancel.internal.h"
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/stat.h"
-#include "libc/elf/def.h"
-#include "libc/elf/elf.h"
-#include "libc/elf/struct/ehdr.h"
-#include "libc/elf/struct/phdr.h"
-#include "libc/errno.h"
-#include "libc/intrin/bits.h"
-#include "libc/runtime/runtime.h"
-#include "libc/sysv/consts/map.h"
-#include "libc/sysv/consts/o.h"
-#include "libc/sysv/consts/prot.h"
-
-/**
- * Returns true if ELF executable uses dynamic loading magic.
- */
-bool _IsDynamicExecutable(const char *prog) {
-  bool res;
-  Elf64_Ehdr *e;
-  Elf64_Phdr *p;
-  struct stat st;
-  int i, fd, err;
-  BLOCK_CANCELLATIONS;
-  fd = -1;
-  err = errno;
-  e = MAP_FAILED;
-  if ((fd = open(prog, O_RDONLY)) == -1) {
-    res = false;
-    goto Finish;
-  }
-  if (fstat(fd, &st) == -1 || st.st_size < 64) {
-    res = false;
-    goto Finish;
-  }
-  if ((e = mmap(0, st.st_size, PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
-    res = false;
-    goto Finish;
-  }
-  if (READ32LE(e->e_ident) != READ32LE(ELFMAG)) {
-    res = false;
-    goto Finish;
-  }
-  if (e->e_type == ET_DYN) {
-    res = true;
-    goto Finish;
-  }
-  for (i = 0; i < e->e_phnum; ++i) {
-    p = GetElfProgramHeaderAddress(e, st.st_size, i);
-    if (p->p_type == PT_INTERP || p->p_type == PT_DYNAMIC) {
-      res = true;
-      goto Finish;
-    }
-  }
-  res = false;
-  goto Finish;
-Finish:
-  if (e != MAP_FAILED) munmap(e, st.st_size);
-  if (fd != -1) close(fd);
-  errno = err;
-  ALLOW_CANCELLATIONS;
-  return res;
-}

libc/runtime/metalprintf.greg.c

@@ -36,7 +36,7 @@
  * This only supports %d and %s. It'll will work even if .rodata hasn't
  * been loaded into memory yet.
  */
-_Hide textreal void(MetalPrintf)(const char *fmt, ...) {
+textreal void(MetalPrintf)(const char *fmt, ...) {
   int i;
   char c;
   unsigned u;

libc/runtime/morph.c

@@ -18,22 +18,16 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #define ShouldUseMsabiAttribute() 1
 #include "ape/sections.internal.h"
-#include "libc/calls/calls.h"
-#include "libc/calls/internal.h"
-#include "libc/calls/struct/sigset.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/intrin/asmflag.h"
 #include "libc/intrin/kprintf.h"
 #include "libc/nt/enum/pageflags.h"
 #include "libc/nt/memory.h"
-#include "libc/nt/runtime.h"
 #include "libc/nt/thunk/msabi.h"
-#include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/sysv/consts/nr.h"
 #include "libc/sysv/consts/prot.h"
-#include "libc/sysv/consts/sig.h"
 
 __msabi extern typeof(VirtualProtect) *const __imp_VirtualProtect;
 
@@ -77,24 +71,37 @@ __funline void __morph_mprotect(void *addr, size_t size, int prot, int ntprot) {
 /**
  * Begins code morphing executable.
  *
- * @return 0 on success, or -1 w/ errno
+ * The following example
+ *
+ *     #include <cosmo.h>
+ *     #include <stdlib.h>
+ *
+ *     privileged int main() {  // privileged code is unmodifiable
+ *       ShowCrashReports();    // print report if trapped
+ *       __morph_begin(0);      // make executable code R+W
+ *       *(char *)exit = 0xCC;  // turn exit() into an INT3 trap
+ *       __morph_end();         // make executable code R+X
+ *       exit(0);               // won't actually exit
+ *     }
+ *
+ * shows how the exit() function can be recompiled at runtime to become
+ * an int3 (x86-64) debugger trap. What makes it tricky is Cosmopolitan
+ * maintains a R^X invariant, in order to support OpenBSD. So when code
+ * wants to modify some part of the executable image in memory the vast
+ * majority of the code stops being executable during that time, unless
+ * it's been linked into a special privileged section of the binary. It
+ * is only possible to code morph from privileged functions. Privileged
+ * functions are also only allowed to call other privileged functions.
  */
-privileged void __morph_begin(sigset_t *save) {
-  int ax;
-  bool cf;
-  intptr_t dx;
-  sigset_t ss = {{-1, -1}};
+privileged void __morph_begin(void) {
   __morph_mprotect(__executable_start, __privileged_start - __executable_start,
                    PROT_READ | PROT_WRITE, kNtPageWritecopy);
 }
 
 /**
- * Begins code morphing executable.
+ * Finishes code morphing executable.
  */
-privileged void __morph_end(sigset_t *save) {
-  int ax;
-  long dx;
-  bool cf;
+privileged void __morph_end(void) {
   __morph_mprotect(__executable_start, __privileged_start - __executable_start,
                    PROT_READ | PROT_EXEC, kNtPageExecuteRead);
 }

libc/runtime/morph.h

@@ -1,12 +0,0 @@
-#ifndef COSMOPOLITAN_LIBC_RUNTIME_MORPH_H_
-#define COSMOPOLITAN_LIBC_RUNTIME_MORPH_H_
-#include "libc/calls/struct/sigset.h"
-#if !(__ASSEMBLER__ + __LINKER__ + 0)
-COSMOPOLITAN_C_START_
-
-void __morph_begin(sigset_t *);
-void __morph_end(sigset_t *);
-
-COSMOPOLITAN_C_END_
-#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
-#endif /* COSMOPOLITAN_LIBC_RUNTIME_MORPH_H_ */

libc/runtime/morph_tls.c

@@ -17,11 +17,9 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "ape/sections.internal.h"
-#include "libc/dce.h"
 #include "libc/intrin/bits.h"
-#include "libc/intrin/kprintf.h"
 #include "libc/runtime/internal.h"
-#include "libc/runtime/morph.h"
+#include "libc/runtime/runtime.h"
 #include "libc/thread/tls.h"
 
 typedef char xmm_t __attribute__((__vector_size__(16), __aligned__(1)));
@@ -47,10 +45,9 @@ privileged void __morph_tls(void) {
   // have actually been linked into this program.
   int n;
   uint64_t w;
-  sigset_t mask;
   unsigned m, dis;
   unsigned char *p;
-  __morph_begin(&mask);
+  __morph_begin();
 
   if (IsXnu()) {
     // Apple is quite straightforward to patch. We basically
@@ -114,6 +111,6 @@ privileged void __morph_tls(void) {
     }
   }
 
-  __morph_end(&mask);
+  __morph_end();
 #endif
 }

libc/runtime/runtime.h

@@ -103,7 +103,6 @@ int _cocmd(int, char **, char **);
 char *GetProgramExecutableName(void);
 char *GetInterpreterExecutableName(char *, size_t);
 int _OpenExecutable(void);
-bool _IsDynamicExecutable(const char *);
 /* execution control */
 int verynice(void);
 axdx_t setlongerjmp(jmp_buf)
@@ -121,6 +120,9 @@ void *_mapanon(size_t) attributeallocsize((1)) mallocesque;
 void *_mapshared(size_t) attributeallocsize((1)) mallocesque;
 void __oom_hook(size_t);
 bool _isheap(void *);
+/* code morphing */
+void __morph_begin(void);
+void __morph_end(void);
 /* portability */
 int NtGetVersion(void) pureconst;
 bool IsGenuineBlink(void);

libc/runtime/runtime.mk

@@ -123,13 +123,15 @@ o/$(MODE)/libc/runtime/enable_tls.o: private		\
 endif
 
 # privileged functions
+o/$(MODE)/libc/runtime/morph.o				\
 o/$(MODE)/libc/runtime/getsymbol.o			\
 o/$(MODE)/libc/runtime/enable_threads.o			\
 o/$(MODE)/libc/runtime/morph_tls.o: private		\
 		CFLAGS +=				\
 			-ffreestanding			\
 			-fno-sanitize=all		\
-			-fno-stack-protector
+			-fno-stack-protector		\
+			-fpatchable-function-entry=0,0
 
 # TODO(jart): We need a way to avoid WinThreadEntry() being hooked.
 o/$(MODE)/libc/runtime/clone.o: private			\

libc/runtime/winmain.greg.c

@@ -67,7 +67,7 @@ __msabi extern typeof(VirtualProtect) *const __imp_VirtualProtect;
 
 extern int64_t __wincrashearly;
 extern const char kConsoleHandles[3];
-extern void cosmo(int, char **, char **, long (*)[2]) _Hide wontreturn;
+extern void cosmo(int, char **, char **, long (*)[2]) wontreturn;
 
 static const short kConsoleModes[3] = {
     kNtEnableProcessedInput | kNtEnableLineInput | kNtEnableEchoInput |