Use %gs as TLS register when dlopen() is linked

Fixes #938

libc/calls/close-nt.c

@@ -28,6 +28,8 @@
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/errfuns.h"
 
+void sys_fcntl_nt_lock_cleanup(int);
+
 textwindows int sys_close_nt(int fd, int fildes) {
   if (fd + 0u >= g_fds.n) return ebadf();
   struct Fd *f = g_fds.p + fd;
@@ -35,7 +37,6 @@ textwindows int sys_close_nt(int fd, int fildes) {
     case kFdEmpty:
       return ebadf();
     case kFdFile:
-      void sys_fcntl_nt_lock_cleanup(int);
       if (_weaken(sys_fcntl_nt_lock_cleanup)) {
         _weaken(sys_fcntl_nt_lock_cleanup)(fildes);
       }

libc/calls/getprogramexecutablename.greg.c

@@ -136,10 +136,11 @@ static inline void InitProgramExecutableNameImpl(void) {
   }
 
   // give up and just copy argv[0] into it
+  char *p, *e;
   if ((q = __argv[0])) {
   CopyString:
-    char *p = g_prog.u.buf;
-    char *e = p + sizeof(g_prog.u.buf);
+    p = g_prog.u.buf;
+    e = p + sizeof(g_prog.u.buf);
     while ((c = *q++)) {
       if (p + 1 < e) {
         *p++ = c;

libc/calls/park.c

@@ -35,6 +35,7 @@ static textwindows int _park_thread(uint32_t msdelay, sigset_t waitmask,
   if ((sig = __sig_get(waitmask))) goto HandleSignal;
   int expect = 0;
   atomic_int futex = 0;
+  int handler_was_called;
   struct PosixThread *pt = _pthread_self();
   pt->pt_blkmask = waitmask;
   atomic_store_explicit(&pt->pt_blocker, &futex, memory_order_release);
@@ -42,7 +43,7 @@ static textwindows int _park_thread(uint32_t msdelay, sigset_t waitmask,
   atomic_store_explicit(&pt->pt_blocker, 0, memory_order_release);
   if (ok && (sig = __sig_get(waitmask))) {
   HandleSignal:
-    int handler_was_called = __sig_relay(sig, SI_KERNEL, waitmask);
+    handler_was_called = __sig_relay(sig, SI_KERNEL, waitmask);
     if (_check_cancel() == -1) return -1;
     if (!restartable || (handler_was_called & SIG_HANDLED_NO_RESTART)) {
       return eintr();

libc/calls/read-nt.c

@@ -723,6 +723,7 @@ static textwindows int WaitForConsole(struct Fd *f, sigset_t waitmask) {
   int sig;
   int64_t sem;
   uint32_t wi, ms = -1;
+  int handler_was_called;
   if (!__ttyconf.vmin) {
     if (!__ttyconf.vtime) {
       return 0;  // non-blocking w/o raising eagain
@@ -745,7 +746,7 @@ static textwindows int WaitForConsole(struct Fd *f, sigset_t waitmask) {
   if (wi != 1) return __winerr();      // wait failed
   if (!(sig = __sig_get(waitmask))) return eintr();
 DeliverSignal:
-  int handler_was_called = __sig_relay(sig, SI_KERNEL, waitmask);
+  handler_was_called = __sig_relay(sig, SI_KERNEL, waitmask);
   if (_check_cancel() == -1) return -1;
   if (!(handler_was_called & SIG_HANDLED_NO_RESTART)) return -2;
   return eintr();

libc/calls/readwrite-nt.c

@@ -47,7 +47,9 @@ sys_readwrite_nt(int fd, void *data, size_t size, ssize_t offset,
                  bool32 ReadOrWriteFile(int64_t, void *, uint32_t, uint32_t *,
                                         struct NtOverlapped *)) {
   int sig;
+  bool eagained;
   uint32_t exchanged;
+  int handler_was_called;
   struct Fd *f = g_fds.p + fd;
 
   // win32 i/o apis generally take 32-bit values thus we implicitly
@@ -79,7 +81,7 @@ sys_readwrite_nt(int fd, void *data, size_t size, ssize_t offset,
   }
 
 RestartOperation:
-  bool eagained = false;
+  eagained = false;
   // check for signals and cancelation
   if (_check_cancel() == -1) return -1;  // ECANCELED
   if ((sig = __sig_get(waitmask))) goto HandleInterrupt;
@@ -132,7 +134,7 @@ RestartOperation:
     // otherwise it must be due to a kill() via __sig_cancel()
     if ((sig = __sig_get(waitmask))) {
     HandleInterrupt:
-      int handler_was_called = __sig_relay(sig, SI_KERNEL, waitmask);
+      handler_was_called = __sig_relay(sig, SI_KERNEL, waitmask);
       if (_check_cancel() == -1) return -1;  // possible if we SIGTHR'd
       // read() is @restartable unless non-SA_RESTART hands were called
       if (!(handler_was_called & SIG_HANDLED_NO_RESTART)) {

libc/dlopen/dlopen.c

@@ -39,6 +39,7 @@
 #include "libc/nt/errors.h"
 #include "libc/nt/memory.h"
 #include "libc/nt/runtime.h"
+#include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/syslib.internal.h"
 #include "libc/stdio/stdio.h"
@@ -75,17 +76,6 @@ __static_yoink(".dlopen.aarch64.glibc.elf");
 #define XNU_RTLD_LOCAL  4
 #define XNU_RTLD_GLOBAL 8
 
-#define BEGIN_FOREIGN                         \
-  {                                           \
-    struct CosmoTib *cosmo_tib = __get_tls(); \
-    pthread_mutex_lock(&foreign.lock);        \
-    __set_tls(foreign.tib)
-
-#define END_FOREIGN                    \
-  __set_tls(cosmo_tib);                \
-  pthread_mutex_unlock(&foreign.lock); \
-  }
-
 struct loaded {
   char *base;
   char *entry;
@@ -96,8 +86,6 @@ struct loaded {
 static struct {
   atomic_uint once;
   bool is_supported;
-  struct CosmoTib *tib;
-  pthread_mutex_t lock;
   void *(*dlopen)(const char *, int);
   void *(*dlsym)(void *, const char *);
   int (*dlclose)(void *);
@@ -312,7 +300,6 @@ static void foreign_setup(void) {
   if (!dlopen_helper) {
     return;  // this platform isn't supported yet
   }
-  struct CosmoTib *cosmo_tib = __get_tls();
   if (!setjmp(foreign.jb)) {
     elf_exec(dlopen_helper, interp, 2,
              (char *[]){
@@ -323,8 +310,6 @@ static void foreign_setup(void) {
              environ);
     return;  // if it returns then it failed
   }
-  foreign.tib = __get_tls();
-  __set_tls(cosmo_tib);
   foreign.is_supported = true;
 }
 
@@ -391,15 +376,17 @@ static char *dlsym_nt_alloc_rwx_block(void) {
 static void *dlsym_nt_alloc_rwx(size_t n) {
   void *res;
   static char *block;
-  pthread_mutex_lock(&foreign.lock);
+  static pthread_spinlock_t lock;
+  pthread_spin_lock(&lock);
   if (!block || READ32LE(block) + n > 65536) {
     if (!(block = dlsym_nt_alloc_rwx_block())) {
+      pthread_spin_unlock(&lock);
       return 0;
     }
   }
   res = block + READ32LE(block);
   WRITE32LE(block, READ32LE(block) + n);
-  pthread_mutex_unlock(&foreign.lock);
+  pthread_spin_unlock(&lock);
   return res;
 }
 
@@ -495,9 +482,7 @@ void *dlopen(const char *path, int mode) {
     last_dlerror = "dlopen() isn't supported on x86-64 MacOS";
     res = 0;
   } else if (foreign_init()) {
-    BEGIN_FOREIGN;
     res = foreign.dlopen(path, mode);
-    END_FOREIGN;
   } else {
     res = 0;
   }
@@ -524,9 +509,7 @@ void *dlsym(void *handle, const char *name) {
     last_dlerror = "dlopen() isn't supported on x86-64 MacOS";
     res = 0;
   } else if (foreign_init()) {
-    BEGIN_FOREIGN;
     res = foreign.dlsym(handle, name);
-    END_FOREIGN;
   } else {
     res = 0;
   }
@@ -550,9 +533,7 @@ int dlclose(void *handle) {
     last_dlerror = "dlopen() isn't supported on x86-64 MacOS";
     res = -1;
   } else if (foreign_init()) {
-    BEGIN_FOREIGN;
     res = foreign.dlclose(handle);
-    END_FOREIGN;
   } else {
     res = -1;
   }
@@ -570,12 +551,24 @@ char *dlerror(void) {
   } else if (IsWindows() || IsXnu()) {
     res = (char *)last_dlerror;
   } else if (foreign_init()) {
-    BEGIN_FOREIGN;
     res = foreign.dlerror();
-    END_FOREIGN;
   } else {
     res = (char *)last_dlerror;
   }
   STRACE("dlerror() → %#s", res);
   return res;
 }
+
+#ifdef __x86_64__
+static textstartup void dlopen_init() {
+  if (IsLinux() || IsFreebsd() || IsNetbsd()) {
+    // switch from %fs to %gs for tls
+    struct CosmoTib *tib = __get_tls();
+    __morph_tls();
+    __set_tls(tib);
+  }
+}
+const void *const dlopen_ctor[] initarray = {
+    dlopen_init,
+};
+#endif

libc/intrin/tlsmorphed.c

@@ -0,0 +1,21 @@
+/*-*- 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/runtime/internal.h"
+
+bool __tls_morphed;

libc/proc/wait4-nt.c

@@ -72,7 +72,7 @@ static textwindows int __proc_wait(int pid, int *wstatus, int options,
   for (;;) {
 
     // check for signals and cancelation
-    int sig, handler_was_called;
+    int rc, sig, handler_was_called;
     if (_check_cancel() == -1) {
       return -1;
     }
@@ -89,7 +89,7 @@ static textwindows int __proc_wait(int pid, int *wstatus, int options,
     // check for zombie to harvest
     __proc_lock();
   CheckForZombies:
-    int rc = __proc_check(pid, wstatus, rusage);
+    rc = __proc_check(pid, wstatus, rusage);
     if (rc || (options & WNOHANG)) {
       __proc_unlock();
       return rc;

libc/runtime/morph_tls.c

@@ -55,11 +55,13 @@ privileged void __morph_tls(void) {
     // address 0x30 was promised to us, according to Go team
     // https://github.com/golang/go/issues/23617
     dis = 0x30;
-  } else {
+  } else if (IsWindows()) {
     // MSVC __declspec(thread) generates binary code for this
     // %gs:0x1480 abi. So long as TlsAlloc() isn't called >64
     // times we should be good.
     dis = 0x1480 + __tls_index * 8;
+  } else {
+    dis = 0;
   }
 
   // iterate over modifiable code looking for 9 byte instruction
@@ -112,6 +114,7 @@ privileged void __morph_tls(void) {
     }
   }
 
+  __tls_morphed = true;
   __morph_end();
 #endif
 }

libc/runtime/set_tls.c

@@ -26,6 +26,9 @@
 #include "libc/thread/tls.h"
 #include "libc/thread/tls2.internal.h"
 
+#define AMD64_SET_FSBASE 129
+#define AMD64_SET_GSBASE 131
+
 int sys_set_tls();
 
 textstartup void __set_tls(struct CosmoTib *tib) {
@@ -36,9 +39,9 @@ textstartup void __set_tls(struct CosmoTib *tib) {
     npassert(0 <= __tls_index && __tls_index < 64);
     asm("mov\t%1,%%gs:%0" : "=m"(*((long *)0x1480 + __tls_index)) : "r"(tib));
   } else if (IsFreebsd()) {
-    sys_set_tls(129 /*AMD64_SET_FSBASE*/, tib);
+    sys_set_tls(__tls_morphed ? AMD64_SET_GSBASE : AMD64_SET_FSBASE, tib);
   } else if (IsLinux()) {
-    sys_set_tls(ARCH_SET_FS, tib);
+    sys_set_tls(__tls_morphed ? ARCH_SET_GS : ARCH_SET_FS, tib);
   } else if (IsNetbsd()) {
     // netbsd has sysarch(X86_SET_FSBASE) but we can't use that because
     // signal handlers will cause it to be reset due to not setting the

libc/stdio/fmt.c

@@ -705,7 +705,7 @@ haveinc:
   return prec;
 }
 
-static int __fmt_noop(const char *, void *, size_t) {
+static int __fmt_noop(const char *x, void *y, size_t z) {
   return 0;
 }
 

libc/thread/tls.h

@@ -40,6 +40,7 @@ struct CosmoTib {
 };
 
 extern int __threaded;
+extern bool __tls_morphed;
 extern unsigned __tls_index;
 
 char *_mktls(struct CosmoTib **);

libc/thread/tls2.internal.h

@@ -15,7 +15,11 @@ COSMOPOLITAN_C_START_
 __funline struct CosmoTib *__get_tls_privileged(void) {
   char *tib, *lin = (char *)0x30;
   if (IsLinux() || IsFreebsd() || IsNetbsd() || IsOpenbsd() || IsMetal()) {
-    asm("mov\t%%fs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
+    if (!__tls_morphed) {
+      asm("mov\t%%fs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
+    } else {
+      asm("mov\t%%gs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
+    }
   } else {
     asm("mov\t%%gs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
     if (IsWindows()) {