Use re-entrant locks on stdio

libc/calls/interrupts-nt.c

@@ -28,15 +28,18 @@
 
 _Alignas(64) static int rlock;
 
-static privileged inline bool AcquireInterruptPollLock(void) {
+// return 0 on success, or tid of other owner
+static privileged inline int AcquireInterruptPollLock(void) {
   // any thread can poll for interrupts
   // but it's wasteful to have every single thread doing it
-  int me, owner, tries;
-  if (!__threaded) return true;
+  int me, owner = 0;
+  if (__threaded) {
     me = gettid();
+    if (!_lockcmpxchgp(&rlock, &owner, me) && owner == me) {
       owner = 0;
-  if (_lockcmpxchgp(&rlock, &owner, me)) return true;
-  return owner == me;
+    }
+  }
+  return owner;
 }
 
 static textwindows inline void ReleaseInterruptPollLock(void) {
@@ -47,7 +50,7 @@ static textwindows inline void ReleaseInterruptPollLock(void) {
 textwindows bool _check_interrupts(bool restartable, struct Fd *fd) {
   bool res;
   if (__time_critical) return false;
-  if (!AcquireInterruptPollLock()) return false;
+  if (AcquireInterruptPollLock()) return false;
   if (weaken(_check_sigalrm)) weaken(_check_sigalrm)();
   if (weaken(_check_sigchld)) weaken(_check_sigchld)();
   if (fd && weaken(_check_sigwinch)) weaken(_check_sigwinch)(fd);

libc/intrin/gettid.greg.c

@@ -27,6 +27,12 @@ __msabi extern typeof(GetCurrentThreadId) *const __imp_GetCurrentThreadId;
 
 /**
  * Returns current thread id.
+ *
+ * On Linux, and Linux only, this is guaranteed to be equal to getpid()
+ * if this is the main thread. On NetBSD, gettid() for the main thread
+ * is always 1.
+ *
+ * @return thread id greater than zero or -1 w/ errno
  * @asyncsignalsafe
  */
 privileged int gettid(void) {

libc/intrin/spinlock.h

@@ -64,7 +64,7 @@
   do {                                               \
     autotype(lock) __lock = (lock);                  \
     typeof(*__lock) __x;                             \
-    int __tries = 0;                                 \
+    unsigned __tries = 0;                            \
     for (;;) {                                       \
       __atomic_load(__lock, &__x, __ATOMIC_RELAXED); \
       if (!__x && !_trylock_inline(__lock)) {        \

libc/log/log.h

@@ -7,6 +7,7 @@
 #include "libc/calls/struct/winsize.h"
 #include "libc/errno.h"
 #include "libc/nexgen32e/stackframe.h"
+#include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/stdio/stdio.h"
 /*───────────────────────────────────────────────────────────────────────────│─╗
@@ -89,7 +90,8 @@ extern unsigned __log_level; /* log level for runtime check */
     --__ftrace;                                                     \
     flogf(kLogError, __FILE__, __LINE__, NULL, FMT, ##__VA_ARGS__); \
     if (weaken(__die)) weaken(__die)();                             \
-    exit(1);                                                        \
+    __restorewintty();                                              \
+    _Exit(1);                                                       \
     unreachable;                                                    \
   } while (0)
 

libc/log/vflogf.c

@@ -41,24 +41,25 @@
 #define kNontrivialSize (8 * 1000 * 1000)
 
 static struct timespec vflogf_ts;
-_Alignas(64) static int vflogf_lock;
 
 /**
  * Takes corrective action if logging is on the fritz.
  */
-void vflogf_onfail(FILE *f) {
+static void vflogf_onfail(FILE *f) {
   errno_t err;
   int64_t size;
   if (IsTiny()) return;
-  err = ferror(f);
-  if (fileno(f) != -1 && (err == ENOSPC || err == EDQUOT || err == EFBIG) &&
-      ((size = getfiledescriptorsize(fileno(f))) == -1 ||
+  err = ferror_unlocked(f);
+  if (fileno_unlocked(f) != -1 &&
+      (err == ENOSPC || err == EDQUOT || err == EFBIG) &&
+      ((size = getfiledescriptorsize(fileno_unlocked(f))) == -1 ||
        size > kNontrivialSize)) {
-    ftruncate(fileno(f), 0);
-    fseek(f, SEEK_SET, 0);
+    ftruncate(fileno_unlocked(f), 0);
+    fseeko_unlocked(f, SEEK_SET, 0);
     f->beg = f->end = 0;
-    clearerr(f);
-    (fprintf)(f, "performed emergency log truncation: %s\n", strerror(err));
+    clearerr_unlocked(f);
+    (fprintf_unlocked)(f, "performed emergency log truncation: %s\n",
+                       strerror(err));
   }
 }
 
@@ -88,8 +89,8 @@ void(vflogf)(unsigned level, const char *file, int line, FILE *f,
   int64_t secs, nsec, dots;
   if (!f) f = __log_file;
   if (!f) return;
-  _spinlock(&vflogf_lock);
-  __atomic_fetch_sub(&__strace, 1, __ATOMIC_RELAXED);
+  flockfile(f);
+  --__strace;
 
   t2 = nowl();
   secs = t2;
@@ -105,16 +106,17 @@ void(vflogf)(unsigned level, const char *file, int line, FILE *f,
   bufmode = f->bufmode;
   if (bufmode == _IOLBF) f->bufmode = _IOFBF;
 
-  if ((fprintf)(f, "%r%c%s%06ld:%s:%d:%.*s:%d] ", "FEWIVDNT"[level & 7], buf32,
+  if ((fprintf_unlocked)(f, "%r%c%s%06ld:%s:%d:%.*s:%d] ",
+                         "FEWIVDNT"[level & 7], buf32,
                          rem1000000int64(div1000int64(dots)), file, line,
                          strchrnul(prog, '.') - prog, prog, getpid()) <= 0) {
     vflogf_onfail(f);
   }
-  (vfprintf)(f, fmt, va);
-  fprintf(f, "\n");
+  (vfprintf_unlocked)(f, fmt, va);
+  fputc_unlocked('\n', f);
   if (bufmode == _IOLBF) {
     f->bufmode = _IOLBF;
-    fflush(f);
+    fflush_unlocked(f);
   }
 
   if (level == kLogFatal) {
@@ -122,11 +124,10 @@ void(vflogf)(unsigned level, const char *file, int line, FILE *f,
     strcpy(buf32, "unknown");
     gethostname(buf32, sizeof(buf32));
     (dprintf)(STDERR_FILENO, "fatality %s pid %d\n", buf32, getpid());
-    _spunlock(&vflogf_lock);
     __die();
     unreachable;
   }
 
-  __atomic_fetch_add(&__strace, 1, __ATOMIC_RELAXED);
-  _spunlock(&vflogf_lock);
+  ++__strace;
+  funlockfile(f);
 }

libc/mem/aligned_alloc.c

@@ -27,6 +27,7 @@
  * @return memory address, or NULL w/ errno
  * @throw EINVAL if !IS2POW(a)
  * @see pvalloc()
+ * @threadsafe
  */
 void *aligned_alloc(size_t a, size_t n) {
   if (IS2POW(a)) {

libc/mem/asprintf.c

@@ -26,6 +26,7 @@
  *     portability, since that's guaranteed to work with all libraries
  * @return bytes written (excluding NUL) or -1 w/ errno
  * @see xasprintf() for a better API
+ * @threadsafe
  */
 int(asprintf)(char **strp, const char *fmt, ...) {
   int res;

libc/mem/calloc.S

@@ -26,5 +26,6 @@
 //	@return	rax is memory address, or NULL w/ errno
 //	@note	overreliance on memalign is a sure way to fragment space
 //	@see	dlcalloc()
+//	@threadsafe
 calloc:	jmp	*hook_calloc(%rip)
 	.endfn	calloc,globl

libc/mem/free.S

@@ -28,5 +28,6 @@
 //
 //	@param	rdi is allocation address, which may be NULL
 //	@see	dlfree()
+//	@threadsafe
 free:	jmp	*hook_free(%rip)
 	.endfn	free,globl

libc/mem/get_current_dir_name.c

@@ -28,6 +28,7 @@
  * that'll be returned.
  *
  * @return pointer that must be free()'d, or NULL w/ errno
+ * @threadsafe
  */
 dontdiscard char *get_current_dir_name(void) {
   const char *p;

libc/mem/malloc.S

@@ -33,5 +33,6 @@
 //
 //	@param	rdi is number of bytes needed, coerced to 1+
 //	@return	new memory, or NULL w/ errno
+//	@threadsafe
 malloc:	jmp	*hook_malloc(%rip)
 	.endfn	malloc,globl

libc/mem/malloc_usable_size.S

@@ -35,6 +35,7 @@
 //	@param	rdi is address of allocation
 //	@return	rax is total number of bytes
 //	@see	dlmalloc_usable_size()
+//	@threadsafe
 malloc_usable_size:
 	jmp	*hook_malloc_usable_size(%rip)
 	.endfn	malloc_usable_size,globl

libc/mem/memalign.S

@@ -30,6 +30,7 @@
 //	@param	rsi is number of bytes needed, coerced to 1+
 //	@return	rax is memory address, or NULL w/ errno
 //	@see	valloc(), pvalloc()
+//	@threadsafe
 memalign:
 	jmp	*hook_memalign(%rip)
 	.endfn	memalign,globl

libc/mem/posix_memalign.c

@@ -35,6 +35,7 @@
  * @param bytes is number of bytes to allocate
  * @return return 0 or EINVAL or ENOMEM w/o setting errno
  * @see memalign()
+ * @threadsafe
  */
 int posix_memalign(void **pp, size_t alignment, size_t bytes) {
   int e;

libc/mem/pvalloc.c

@@ -25,6 +25,7 @@
  * @param n number of bytes needed
  * @return memory address, or NULL w/ errno
  * @see valloc()
+ * @threadsafe
  */
 void *pvalloc(size_t n) {
   return memalign(PAGESIZE, ROUNDUP(n, PAGESIZE));

libc/mem/realloc.S

@@ -53,6 +53,7 @@
 //	@note	realloc(p=0, n=0) → malloc(32)
 //	@note	realloc(p≠0, n=0) → free(p)
 //	@see	dlrealloc()
+//	@threadsafe
 realloc:
 	jmp	*hook_realloc(%rip)
 	.endfn	realloc,globl

libc/mem/realloc_in_place.S

@@ -32,6 +32,7 @@
 //	@param	rsi (newsize) is number of bytes needed
 //	@return	rax is result, or NULL w/ errno
 //	@see	dlrealloc_in_place()
+//	@threadsafe
 realloc_in_place:
 	jmp	*hook_realloc_in_place(%rip)
 	.endfn	realloc_in_place,globl

libc/mem/reallocarray.c

@@ -26,6 +26,7 @@
  * @param ptr may be NULL for malloc() behavior
  * @param nmemb may be 0 for free() behavior; shrinking is promised too
  * @return new address or NULL w/ errno and ptr is NOT free()'d
+ * @threadsafe
  */
 void *reallocarray(void *ptr, size_t nmemb, size_t itemsize) {
   size_t n;

libc/mem/strdup.c

@@ -25,6 +25,7 @@
  * @param s is a NUL-terminated byte string
  * @return new string or NULL w/ errno
  * @error ENOMEM
+ * @threadsafe
  */
 char *strdup(const char *s) {
   size_t len = strlen(s);

libc/mem/strndup.c

@@ -26,6 +26,7 @@
  * @param n if less than strlen(s) will truncate the string
  * @return new string or NULL w/ errno
  * @error ENOMEM
+ * @threadsafe
  */
 char *strndup(const char *s, size_t n) {
   char *s2;

libc/mem/valloc.c

@@ -24,6 +24,7 @@
  * @param n number of bytes needed
  * @return memory address, or NULL w/ errno
  * @see pvalloc()
+ * @threadsafe
  */
 void *valloc(size_t n) {
   return memalign(PAGESIZE, n);

libc/mem/vasprintf.c

@@ -23,6 +23,7 @@
 /**
  * Formats string w/ dynamic memory allocation.
  * @see xasprintf() for a better API
+ * @threadsafe
  */
 int(vasprintf)(char **strp, const char *fmt, va_list va) {
   va_list vb;

libc/mem/wcsdup.c

@@ -21,6 +21,7 @@
 
 /**
  * Allocates copy of wide string.
+ * @threadsafe
  */
 wchar_t *wcsdup(const wchar_t *s) {
   size_t len = wcslen(s);

libc/runtime/ftracer.c

@@ -70,7 +70,8 @@ static privileged inline void ReleaseFtraceLock(void) {
 }
 
 static privileged inline bool AcquireFtraceLock(void) {
-  int me, owner, tries;
+  int me, owner;
+  unsigned tries;
   if (!__threaded) {
     return _cmpxchg(&ftrace_lock, 0, -1);
   } else {

libc/stdio/fclose.c

@@ -19,7 +19,6 @@
 #include "libc/assert.h"
 #include "libc/calls/calls.h"
 #include "libc/errno.h"
-#include "libc/intrin/spinlock.h"
 #include "libc/mem/mem.h"
 #include "libc/runtime/runtime.h"
 #include "libc/stdio/internal.h"

libc/stdio/fflush.c

@@ -33,7 +33,7 @@
 /**
  * Blocks until data from stream buffer is written out.
  *
- * @param f is the stream handle
+ * @param f is the stream handle, or 0 for all streams
  * @return is 0 on success or -1 on error
  */
 int fflush_unlocked(FILE *f) {

libc/stdio/flockfile.c

@@ -16,12 +16,28 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/intrin/spinlock.h"
+#include "libc/calls/calls.h"
+#include "libc/intrin/cmpxchg.h"
+#include "libc/intrin/lockcmpxchgp.h"
+#include "libc/nexgen32e/threaded.h"
 #include "libc/stdio/stdio.h"
 
 /**
- * Acquires lock on stdio object, blocking if needed.
+ * Acquires reentrant lock on stdio object, blocking if needed.
  */
 void flockfile(FILE *f) {
-  _spinlock(&f->lock);
+  int me, owner;
+  unsigned tries;
+  if (!__threaded) return;
+  for (tries = 0, me = gettid();;) {
+    owner = 0;
+    if (_lockcmpxchgp(&f->lock, &owner, me) || owner == me) {
+      return;
+    }
+    if (++tries & 7) {
+      __builtin_ia32_pause();
+    } else {
+      sched_yield();
+    }
+  }
 }

libc/stdio/flushlbf.c

@@ -31,11 +31,11 @@ void _flushlbf(void) {
   _spinlock(&__fflush.lock);
   for (i = 0; i < __fflush.handles.i; ++i) {
     if ((f = __fflush.handles.p[i])) {
-      _spinlock(&f->lock);
+      flockfile(f);
       if (f->bufmode == _IOLBF) {
         fflush_unlocked(f);
       }
-      _spunlock(&f->lock);
+      funlockfile(f);
     }
   }
   _spunlock(&__fflush.lock);

libc/stdio/fprintf.c

@@ -18,11 +18,17 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/stdio/stdio.h"
 
+/**
+ * Formats and writes text to stream.
+ * @see printf() for further documentation
+ */
 int(fprintf)(FILE *f, const char *fmt, ...) {
   int rc;
   va_list va;
+  flockfile(f);
   va_start(va, fmt);
-  rc = (vfprintf)(f, fmt, va);
+  rc = (vfprintf_unlocked)(f, fmt, va);
   va_end(va);
+  funlockfile(f);
   return rc;
 }

libc/stdio/fprintf_unlocked.c

@@ -0,0 +1,32 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=8 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 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/stdio/stdio.h"
+
+/**
+ * Formats and writes text to stream.
+ * @see printf() for further documentation
+ */
+int(fprintf_unlocked)(FILE *f, const char *fmt, ...) {
+  int rc;
+  va_list va;
+  va_start(va, fmt);
+  rc = (vfprintf_unlocked)(f, fmt, va);
+  va_end(va);
+  return rc;
+}

libc/stdio/freopen.c

@@ -17,7 +17,6 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
-#include "libc/intrin/spinlock.h"
 #include "libc/stdio/stdio.h"
 #include "libc/sysv/consts/f.h"
 #include "libc/sysv/consts/fd.h"
@@ -41,7 +40,7 @@ FILE *freopen(const char *pathname, const char *mode, FILE *stream) {
   FILE *res;
   unsigned flags;
   flags = fopenflags(mode);
-  _spinlock(&stream->lock);
+  flockfile(stream);
   fflush_unlocked(stream);
   if (pathname) {
     /* open new stream, overwriting existing alloc */
@@ -60,6 +59,6 @@ FILE *freopen(const char *pathname, const char *mode, FILE *stream) {
     fcntl(stream->fd, F_SETFL, flags & ~O_CLOEXEC);
     res = stream;
   }
-  _spunlock(&stream->lock);
+  funlockfile(stream);
   return res;
 }

libc/stdio/fseeko.c

@@ -18,7 +18,6 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/errno.h"
-#include "libc/intrin/spinlock.h"
 #include "libc/stdio/internal.h"
 #include "libc/stdio/stdio.h"
 #include "libc/sysv/consts/o.h"
@@ -36,11 +35,10 @@
  * @param whence can be SEET_SET, SEEK_CUR, or SEEK_END
  * @returns 0 on success or -1 on error
  */
-int fseeko(FILE *f, int64_t offset, int whence) {
+int fseeko_unlocked(FILE *f, int64_t offset, int whence) {
   int res;
   ssize_t rc;
   int64_t pos;
-  _spinlock(&f->lock);
   if (f->fd != -1) {
     if (__fflush_impl(f) == -1) return -1;
     if (whence == SEEK_CUR && f->beg < f->end) {
@@ -77,6 +75,5 @@ int fseeko(FILE *f, int64_t offset, int whence) {
       res = -1;
     }
   }
-  _spunlock(&f->lock);
   return res;
 }

libc/stdio/ftello.c

@@ -18,7 +18,6 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/errno.h"
-#include "libc/intrin/spinlock.h"
 #include "libc/runtime/runtime.h"
 #include "libc/stdio/internal.h"
 #include "libc/stdio/stdio.h"
@@ -49,8 +48,8 @@ static int64_t ftello_unlocked(FILE *f) {
  */
 int64_t ftello(FILE *f) {
   int64_t rc;
-  _spinlock(&f->lock);
+  flockfile(f);
   rc = ftello_unlocked(f);
-  _spunlock(&f->lock);
+  funlockfile(f);
   return rc;
 }

libc/stdio/ftrylockfile.c

@@ -16,13 +16,23 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/intrin/spinlock.h"
+#include "libc/calls/calls.h"
+#include "libc/intrin/lockcmpxchgp.h"
+#include "libc/nexgen32e/threaded.h"
 #include "libc/stdio/stdio.h"
 
 /**
- * Tries to acquire stdio object lock.
- * @return 0 for success or non-zero if someone else has the lock
+ * Tries to acquire reentrant stdio object lock.
+ *
+ * @return 0 on success, or non-zero if another thread owns the lock
  */
 int ftrylockfile(FILE *f) {
-  return _trylock(&f->lock);
+  int me, owner = 0;
+  if (__threaded) {
+    me = gettid();
+    if (!_lockcmpxchgp(&f->lock, &owner, me) && owner == me) {
+      owner = 0;
+    }
+  }
+  return owner;
 }

libc/stdio/getdelim.c

@@ -19,7 +19,6 @@
 #include "libc/assert.h"
 #include "libc/calls/calls.h"
 #include "libc/errno.h"
-#include "libc/intrin/spinlock.h"
 #include "libc/macros.internal.h"
 #include "libc/mem/mem.h"
 #include "libc/runtime/runtime.h"
@@ -87,8 +86,8 @@ static ssize_t getdelim_unlocked(char **s, size_t *n, int delim, FILE *f) {
  */
 ssize_t getdelim(char **s, size_t *n, int delim, FILE *f) {
   ssize_t rc;
-  _spinlock(&f->lock);
+  flockfile(f);
   rc = getdelim_unlocked(s, n, delim, f);
-  _spunlock(&f->lock);
+  funlockfile(f);
   return rc;
 }

libc/stdio/printf.c

@@ -19,7 +19,7 @@
 #include "libc/stdio/stdio.h"
 
 /**
- * Formats and writes string to stdout.
+ * Formats and writes text to stdout.
  *
  * Cosmopolitan supports most of the standard formatting behaviors
  * described by `man 3 printf`, in addition to the following

libc/stdio/puts.c

@@ -18,21 +18,32 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/stdio/stdio.h"
 
-/**
- * Writes string w/ trailing newline to stdout.
- */
-int puts(const char *s) {
-  FILE *f;
+static int PutsImpl(const char *s, FILE *f) {
   size_t n, r;
-  f = stdout;
   if ((n = strlen(s))) {
-    r = fwrite(s, 1, n, f);
+    r = fwrite_unlocked(s, 1, n, f);
     if (!r) return -1;
     if (r < n) return r;
   }
-  if (fputc('\n', f) == -1) {
-    if (feof(f)) return n;
+  if (fputc_unlocked('\n', f) == -1) {
+    if (feof_unlocked(f)) return n;
     return -1;
   }
   return n + 1;
 }
+
+/**
+ * Writes string w/ trailing newline to stdout.
+ *
+ * @return non-negative number on success, or `EOF` on error with
+ *     `errno` set and the `ferror(stdout)` state is updated
+ */
+int puts(const char *s) {
+  FILE *f;
+  int bytes;
+  f = stdout;
+  flockfile(f);
+  bytes = PutsImpl(s, f);
+  funlockfile(f);
+  return bytes;
+}

libc/stdio/rewind.c

@@ -26,6 +26,9 @@
  * EOF state, without reopening it.
  */
 void rewind(FILE *f) {
-  fseek(f, 0, SEEK_SET);
+  flockfile(f);
+  if (!fseeko_unlocked(f, 0, SEEK_SET)) {
     f->state = 0;
+  }
+  funlockfile(f);
 }

libc/stdio/setvbuf.c

@@ -30,6 +30,7 @@
  * @return 0 on success or -1 on error
  */
 int setvbuf(FILE *f, char *buf, int mode, size_t size) {
+  flockfile(f);
   if (buf) {
     if (!size) size = BUFSIZ;
     if (!f->nofree && f->buf != buf) free_s(&f->buf);
@@ -38,5 +39,6 @@ int setvbuf(FILE *f, char *buf, int mode, size_t size) {
     f->nofree = true;
   }
   f->bufmode = mode;
+  funlockfile(f);
   return 0;
 }

libc/stdio/stdio.h

@@ -116,30 +116,6 @@ int wprintf(const wchar_t *, ...);
 int wscanf(const wchar_t *, ...);
 int fwide(FILE *, int);
 
-/*───────────────────────────────────────────────────────────────────────────│─╗
-│ cosmopolitan § standard i/o » optimizations                              ─╬─│┼
-╚────────────────────────────────────────────────────────────────────────────│*/
-
-#define getc(f)     fgetc(f)
-#define getwc(f)    fgetwc(f)
-#define putc(c, f)  fputc(c, f)
-#define putwc(c, f) fputwc(c, f)
-
-#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
-#define printf(FMT, ...)     (printf)(PFLINK(FMT), ##__VA_ARGS__)
-#define vprintf(FMT, VA)     (vprintf)(PFLINK(FMT), VA)
-#define fprintf(F, FMT, ...) (fprintf)(F, PFLINK(FMT), ##__VA_ARGS__)
-#define vfprintf(F, FMT, VA) (vfprintf)(F, PFLINK(FMT), VA)
-#define vscanf(FMT, VA)      (vscanf)(SFLINK(FMT), VA)
-#define scanf(FMT, ...)      (scanf)(SFLINK(FMT), ##__VA_ARGS__)
-#define fscanf(F, FMT, ...)  (fscanf)(F, SFLINK(FMT), ##__VA_ARGS__)
-#define vfscanf(F, FMT, VA)  (vfscanf)(F, SFLINK(FMT), VA)
-#endif
-
-#define stdin  SYMBOLIC(stdin)
-#define stdout SYMBOLIC(stdout)
-#define stderr SYMBOLIC(stderr)
-
 /*───────────────────────────────────────────────────────────────────────────│─╗
 │ cosmopolitan § standard i/o » without mutexes                            ─╬─│┼
 ╚────────────────────────────────────────────────────────────────────────────│*/
@@ -172,12 +148,45 @@ wchar_t *fgetws_unlocked(wchar_t *, int, FILE *);
 int fputws_unlocked(const wchar_t *, FILE *);
 wint_t ungetwc_unlocked(wint_t, FILE *) paramsnonnull();
 int ungetc_unlocked(int, FILE *) paramsnonnull();
+int fseeko_unlocked(FILE *, int64_t, int) paramsnonnull();
+int fprintf_unlocked(FILE *, const char *, ...) printfesque(2)
+    paramsnonnull((1, 2)) dontthrow nocallback;
+int vfprintf_unlocked(FILE *, const char *, va_list)
+    paramsnonnull() dontthrow nocallback;
 
 #define getc_unlocked(f)     fgetc_unlocked(f)
 #define getwc_unlocked(f)    fgetwc_unlocked(f)
 #define putc_unlocked(c, f)  fputc_unlocked(c, f)
 #define putwc_unlocked(c, f) fputwc_unlocked(c, f)
 
+/*───────────────────────────────────────────────────────────────────────────│─╗
+│ cosmopolitan § standard i/o » optimizations                              ─╬─│┼
+╚────────────────────────────────────────────────────────────────────────────│*/
+
+#define getc(f)     fgetc(f)
+#define getwc(f)    fgetwc(f)
+#define putc(c, f)  fputc(c, f)
+#define putwc(c, f) fputwc(c, f)
+
+#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
+/* clang-format off */
+#define printf(FMT, ...)     (printf)(PFLINK(FMT), ##__VA_ARGS__)
+#define vprintf(FMT, VA)     (vprintf)(PFLINK(FMT), VA)
+#define fprintf(F, FMT, ...) (fprintf)(F, PFLINK(FMT), ##__VA_ARGS__)
+#define vfprintf(F, FMT, VA) (vfprintf)(F, PFLINK(FMT),  VA)
+#define fprintf_unlocked(F, FMT, ...) (fprintf_unlocked)(F, PFLINK(FMT), ##__VA_ARGS__)
+#define vfprintf_unlocked(F, FMT, VA) (vfprintf_unlocked)(F, PFLINK(FMT), VA)
+#define vscanf(FMT, VA)      (vscanf)(SFLINK(FMT), VA)
+#define scanf(FMT, ...)      (scanf)(SFLINK(FMT), ##__VA_ARGS__)
+#define fscanf(F, FMT, ...)  (fscanf)(F, SFLINK(FMT), ##__VA_ARGS__)
+#define vfscanf(F, FMT, VA)  (vfscanf)(F, SFLINK(FMT), VA)
+/* clang-format on */
+#endif
+
+#define stdin  SYMBOLIC(stdin)
+#define stdout SYMBOLIC(stdout)
+#define stderr SYMBOLIC(stderr)
+
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_LIBC_STDIO_STDIO_H_ */

libc/stdio/unlocked/clearerr_unlocked.S

@@ -22,6 +22,7 @@
 //
 //	@param	rdi has stream pointer
 //	@see	clearerr_unlocked()
+//	@threadsafe
 clearerr:
 	mov	%rdi,%r11
 	ezlea	clearerr_unlocked,ax

libc/stdio/unlocked/feof_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has file stream object pointer
 //	@note	EOF doesn't count
 //	@see	feof_unlocked()
+//	@threadsafe
 feof:	mov	%rdi,%r11
 	ezlea	feof_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/ferror_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has file stream object pointer
 //	@note	EOF doesn't count
 //	@see	ferror_unlocked()
+//	@threadsafe
 ferror:	mov	%rdi,%r11
 	ezlea	ferror_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fflush_unlocked.S

@@ -20,10 +20,14 @@
 
 //	Blocks until data from stream buffer is written out.
 //
-//	@param	rdi is the stream handle
+//	@param	rdi is the stream handle, or 0 for all streams
 //	@return	0 on success or -1 w/ errno
 //	@see	fflush_unlocked()
-fflush:	mov	%rdi,%r11
-	ezlea	fflush_unlocked,ax
+//	@threadsafe
+fflush:	ezlea	fflush_unlocked,ax
+	test	%rdi,%rdi
+	jz	1f
+	mov	%rdi,%r11
 	jmp	stdio_unlock
+1:	jmp	*%rax
 	.endfn	fflush,globl

libc/stdio/unlocked/fgetc_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has stream object pointer
 //	@return byte in range 0..255, or -1 w/ errno
 //	@see	fgetc_unlocked()
+//	@threadsafe
 fgetc:	mov	%rdi,%r11
 	ezlea	fgetc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fgets_unlocked.S

@@ -30,6 +30,7 @@
 //	@return	rax has rdi on success, NULL on error or
 //		NULL if EOF happens with zero chars read
 //	@see	fgets_unlocked()
+//	@threadsafe
 fgets:	mov	%rdx,%r11
 	ezlea	fgets_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fgetwc_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has stream object pointer
 //	@return wide character or -1 on EOF or error
 //	@see	fgetwc_unlocked()
+//	@threadsafe
 fgetwc:	mov	%rdi,%r11
 	ezlea	fgetwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fgetws_unlocked.S

@@ -28,6 +28,7 @@
 //	@param	rsi is size of rdi buffer
 //	@param	rsi is file stream object pointer
 //	@see	fgetws_unlocked()
+//	@threadsafe
 fgetws:	mov	%rdx,%r11
 	ezlea	fgetws_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fileno_unlocked.S

@@ -22,6 +22,7 @@
 //
 //	@param	rdi has file stream object pointer
 //	@see	fileno_unlocked()
+//	@threadsafe
 fileno:	mov	%rdi,%r11
 	ezlea	fileno_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fputc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rsi has stream object pointer
 //	@return c as unsigned char if written or -1 w/ errno
 //	@see	fputc_unlocked()
+//	@threadsafe
 fputc:	mov	%rsi,%r11
 	ezlea	fputc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fputs_unlocked.S

@@ -28,6 +28,7 @@
 //	@param	rsi is file object stream pointer
 //	@return	strlen(rdi) on success or -1 w/ errno
 //	@see	fputs_unlocked()
+//	@threadsafe
 fputs:	mov	%rsi,%r11
 	ezlea	fputs_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fputwc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rsi has file object stream pointer
 //	@return	rax is wide character if written or -1 w/ errno
 //	@see	fputwc_unlocked()
+//	@threadsafe
 fputwc:	mov	%rsi,%r11
 	ezlea	fputwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fputws_unlocked.S

@@ -28,6 +28,7 @@
 //	@param	rsi is file object stream pointer
 //	@return	strlen(rdi) on success or -1 w/ errno
 //	@see	fputws_unlocked()
+//	@threadsafe
 fputws:	mov	%rsi,%r11
 	ezlea	fputws_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fread_unlocked.S

@@ -26,6 +26,7 @@
 //	@param	rcx has file object stream pointer
 //	@return	count on success, [0,count) on EOF, 0 on error or count==0
 //	@see	fread_unlocked()
+//	@threadsafe
 fread:	mov	%rcx,%r11
 	ezlea	fread_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/fseeko_unlocked.S

@@ -0,0 +1,37 @@
+/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
+│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 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/macros.internal.h"
+
+//	Repositions open file stream.
+//
+//	This function flushes the buffer (unless it's currently in the EOF
+//	state) and then calls lseek() on the underlying file. If the stream
+//	is in the EOF state, this function can be used to restore it without
+//	needing to reopen the file.
+//
+//	@param	rdi is stream handle
+//	@param	rsi is offset is the byte delta
+//	@param	rdx is whence and can be SEET_SET, SEEK_CUR, or SEEK_END
+//	@return	0 on success or -1 w/ errno
+//	@see	fflush_unlocked()
+//	@threadsafe
+fseeko:	mov	%rdi,%r11
+	ezlea	fseeko_unlocked,ax
+	jmp	stdio_unlock
+	.endfn	fseeko,globl

libc/stdio/unlocked/fwrite_unlocked.S

@@ -26,6 +26,7 @@
 //	@param	rcx has file object stream pointer
 //	@return	count on success, [0,count) on EOF, 0 on error or count==0
 //	@see	fwrite_unlocked()
+//	@threadsafe
 fwrite:	mov	%rcx,%r11
 	ezlea	fwrite_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/getc_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has file stream object pointer
 //	@return	byte in range 0..255, or -1 w/ errno
 //	@see	fgetc_unlocked()
+//	@threadsafe
 getc:	mov	%rdi,%r11
 	ezlea	fgetwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/getchar_unlocked.S

@@ -22,6 +22,7 @@
 //
 //	@return	byte in range 0..255, or -1 w/ errno
 //	@see	fgetc_unlocked()
+//	@threadsafe
 getchar:
 	mov	stdin(%rip),%rdi
 	mov	%rdi,%r11

libc/stdio/unlocked/getwc_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has file stream object pointer
 //	@return	wide character or -1 on EOF or error
 //	@see	fgetwc_unlocked()
+//	@threadsafe
 getwc:	mov	%rdi,%r11
 	ezlea	fgetwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/getwchar_unlocked.S

@@ -22,6 +22,7 @@
 //
 //	@return	wide character or -1 on EOF or error
 //	@see	fgetwc_unlocked()
+//	@threadsafe
 getwchar:
 	mov	stdin(%rip),%rdi
 	mov	%rdi,%r11

libc/stdio/unlocked/putc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rsi has stream object pointer
 //	@return c as unsigned char if written or -1 w/ errno
 //	@see	fputc_unlocked()
+//	@threadsafe
 putc:	mov	%rsi,%r11
 	ezlea	fputc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/putchar_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has character
 //	@return c (as unsigned char) if written or -1 w/ errno
 //	@see	fputc_unlocked()
+//	@threadsafe
 putchar:
 	mov	stdout(%rip),%rsi
 	mov	%rsi,%r11

libc/stdio/unlocked/putwc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rsi has file object
 //	@return wc if written or -1 w/ errno
 //	@see	putwc_unlocked()
+//	@threadsafe
 putwc:	mov	%rsi,%r11
 	ezlea	fputwc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/putwchar_unlocked.S

@@ -23,6 +23,7 @@
 //	@param	rdi has wide character
 //	@return wc if written or -1 w/ errno
 //	@see	fputwc_unlocked()
+//	@threadsafe
 putwchar:
 	mov	stdout(%rip),%rsi
 	mov	%rsi,%r11

libc/stdio/unlocked/stdio_unlock.S

@@ -18,53 +18,54 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.internal.h"
 
-#define LOCK 0x2c /* see struct file in stdio.h */
-
 //	Wrapper for applying locking to stdio functions.
 //
 //	This function is intended to be called by thunks.
 //
-//	@param	rax has the delegate function pointer
+//	@param	rax is stdio function pointer
 //	@param	rdi is passed along as an arg
 //	@param	rsi is passed along as an arg
 //	@param	rdx is passed along as an arg
 //	@param	rcx is passed along as an arg
-//	@param	r8  is passed along as an arg
-//	@param	r9  is passed along as an arg
-//	@param	r10 is passed along as an arg
 //	@param	r11 has the FILE* obj pointer
 //	@return	rax is passed along as result
 //	@return	rdx is passed along as result
+//	@threadsafe
 stdio_unlock:
 	push	%rbp
 	mov	%rsp,%rbp
 	.profilable
 
 //	acquires mutex
-	push	%rcx
+	push	%rax
+	push	%rdi
+	push	%rsi
 	push	%rdx
-	mov	$1,%cl
-0:	mov	LOCK(%r11),%dl			# optimistic
-	test	%dl,%dl
-	je	2f
-1:	pause					# hyperyield
-	jmp	0b
-2:	mov	%ecx,%edx
-	xchg	LOCK(%r11),%dl			# locks bus!
-	test	%dl,%dl
-	jne	1b
-	pop	%rdx
+	push	%rcx
+	push	%r11
+	mov	%r11,%rdi
+	call	flockfile
+	pop	%r11
 	pop	%rcx
+	pop	%rdx
+	pop	%rsi
+	pop	%rdi
+	pop	%rax
 
 //	calls delegate
-	push	%rsi
 	push	%r11
+	push	%rsi			# align stack
 	call	*%rax
-	pop	%r11
 	pop	%rsi
+	pop	%r11
 
 //	releases mutex
-	movb	$0,LOCK(%r11)
+	push	%rax
+	push	%rdx
+	mov	%r11,%rdi
+	call	funlockfile
+	pop	%rdx
+	pop	%rax
 
 	pop	%rbp
 	ret

libc/stdio/unlocked/ungetc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rds has stream object pointer
 //	@return rax has rdi on success or -1 w/ errno
 //	@see	ungetc_unlocked()
+//	@threadsafe
 ungetc:	mov	%rsi,%r11
 	ezlea	ungetc_unlocked,ax
 	jmp	stdio_unlock

libc/stdio/unlocked/ungetwc_unlocked.S

@@ -24,6 +24,7 @@
 //	@param	rds has stream object pointer
 //	@return rax has rdi on success or -1 w/ errno
 //	@see	ungetwc_unlocked()
+//	@threadsafe
 ungetwc:
 	mov	%rsi,%r11
 	ezlea	ungetwc_unlocked,ax

libc/stdio/vfprintf.c

@@ -16,45 +16,16 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/calls/calls.h"
-#include "libc/fmt/fmt.h"
-#include "libc/intrin/spinlock.h"
-#include "libc/limits.h"
 #include "libc/stdio/stdio.h"
-#include "libc/sysv/errfuns.h"
-
-struct state {
-  FILE *f;
-  int n;
-};
-
-static int vfprintfputchar(const char *s, struct state *t, size_t n) {
-  int rc;
-  if (n) {
-    _spinlock(&t->f->lock);
-    if (n == 1 && *s != '\n' && t->f->beg < t->f->size &&
-        t->f->bufmode != _IONBF) {
-      t->f->buf[t->f->beg++] = *s;
-      t->n += n;
-      rc = 0;
-    } else if (!fwrite_unlocked(s, 1, n, t->f)) {
-      rc = -1;
-    } else {
-      t->n += n;
-      rc = 0;
-    }
-    _spunlock(&t->f->lock);
-  } else {
-    rc = 0;
-  }
-  return 0;
-}
 
+/**
+ * Formats and writes text to stream.
+ * @see printf() for further documentation
+ */
 int(vfprintf)(FILE *f, const char *fmt, va_list va) {
-  struct state st[1] = {{f, 0}};
-  if (__fmt(vfprintfputchar, st, fmt, va) != -1) {
-    return st->n;
-  } else {
-    return -1;
-  }
+  int rc;
+  flockfile(f);
+  rc = (vfprintf_unlocked)(f, fmt, va);
+  funlockfile(f);
+  return rc;
 }

libc/stdio/vfprintf_unlocked.c

@@ -0,0 +1,61 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=8 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 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/fmt/fmt.h"
+#include "libc/limits.h"
+#include "libc/stdio/stdio.h"
+#include "libc/sysv/errfuns.h"
+
+struct state {
+  FILE *f;
+  int n;
+};
+
+static int vfprintfputchar(const char *s, struct state *t, size_t n) {
+  int rc;
+  if (n) {
+    if (n == 1 && *s != '\n' && t->f->beg < t->f->size &&
+        t->f->bufmode != _IONBF) {
+      t->f->buf[t->f->beg++] = *s;
+      t->n += n;
+      rc = 0;
+    } else if (!fwrite_unlocked(s, 1, n, t->f)) {
+      rc = -1;
+    } else {
+      t->n += n;
+      rc = 0;
+    }
+  } else {
+    rc = 0;
+  }
+  return 0;
+}
+
+/**
+ * Formats and writes text to stream.
+ * @see printf() for further documentation
+ */
+int(vfprintf_unlocked)(FILE *f, const char *fmt, va_list va) {
+  int rc;
+  struct state st[1] = {{f, 0}};
+  if ((rc = __fmt(vfprintfputchar, st, fmt, va)) != -1) {
+    rc = st->n;
+  }
+  return rc;
+}

libc/stdio/vprintf.c

@@ -18,6 +18,10 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/stdio/stdio.h"
 
+/**
+ * Formats and writes text to stdout.
+ * @see printf() for further documentation
+ */
 int(vprintf)(const char* fmt, va_list va) {
   return (vfprintf)(stdout, fmt, va);
 }

test/libc/stdio/fputc_test.c

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/stdio/stdio.h"
+#include "libc/testlib/ezbench.h"
 #include "libc/testlib/testlib.h"
 
 FILE *f;
@@ -60,3 +61,13 @@ TEST(fgetc, testUnbuffered) {
   EXPECT_TRUE(feof(f));
   EXPECT_NE(-1, fclose(f));
 }
+
+BENCH(fputc, bench) {
+  FILE *f;
+  ASSERT_NE(NULL, (f = fopen("/dev/null", "w")));
+  EZBENCH2("fputc", donothing, fputc('E', f));
+  flockfile(f);
+  EZBENCH2("fputc_unlocked", donothing, fputc_unlocked('E', f));
+  funlockfile(f);
+  fclose(f);
+}

third_party/mbedtls/ssl.h

@@ -12,20 +12,6 @@
 COSMOPOLITAN_C_START_
 /* clang-format off */
 
-#define MBEDTLS_ERR_NET_SOCKET_FAILED                     -0x0042  /*< Failed to open a socket. */
-#define MBEDTLS_ERR_NET_CONNECT_FAILED                    -0x0044  /*< The connection to the given server / port failed. */
-#define MBEDTLS_ERR_NET_BIND_FAILED                       -0x0046  /*< Binding of the socket failed. */
-#define MBEDTLS_ERR_NET_LISTEN_FAILED                     -0x0048  /*< Could not listen on the socket. */
-#define MBEDTLS_ERR_NET_ACCEPT_FAILED                     -0x004A  /*< Could not accept the incoming connection. */
-#define MBEDTLS_ERR_NET_RECV_FAILED                       -0x004C  /*< Reading information from the socket failed. */
-#define MBEDTLS_ERR_NET_SEND_FAILED                       -0x004E  /*< Sending information through the socket failed. */
-#define MBEDTLS_ERR_NET_CONN_RESET                        -0x0050  /*< Connection was reset by peer. */
-#define MBEDTLS_ERR_NET_UNKNOWN_HOST                      -0x0052  /*< Failed to get an IP address for the given hostname. */
-#define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL                  -0x0043  /*< Buffer is too small to hold the data. */
-#define MBEDTLS_ERR_NET_INVALID_CONTEXT                   -0x0045  /*< The context is invalid, eg because it was free()ed. */
-#define MBEDTLS_ERR_NET_POLL_FAILED                       -0x0047  /*< Polling the net context failed. */
-#define MBEDTLS_ERR_NET_BAD_INPUT_DATA                    -0x0049  /*< Input invalid. */
-
 /*
  * SSL Error codes
  */

tool/build/lib/eztls.c

@@ -29,6 +29,7 @@
 #include "third_party/mbedtls/ctr_drbg.h"
 #include "third_party/mbedtls/ecp.h"
 #include "third_party/mbedtls/error.h"
+#include "third_party/mbedtls/net_sockets.h"
 #include "third_party/mbedtls/platform.h"
 #include "third_party/mbedtls/ssl.h"
 #include "tool/build/lib/eztls.h"

tool/build/runit.c

@@ -51,6 +51,7 @@
 #include "libc/time/time.h"
 #include "libc/x/x.h"
 #include "net/https/https.h"
+#include "third_party/mbedtls/net_sockets.h"
 #include "third_party/mbedtls/ssl.h"
 #include "third_party/zlib/zlib.h"
 #include "tool/build/lib/eztls.h"
@@ -112,6 +113,7 @@ static const struct addrinfo kResolvHints = {.ai_family = AF_INET,
 
 int g_sock;
 char *g_prog;
+long g_backoff;
 char *g_runitd;
 jmp_buf g_jmpbuf;
 uint16_t g_sshport;
@@ -308,7 +310,7 @@ TryAgain:
   freeaddrinfo(ai);
 }
 
-static void Send(const void *output, size_t outputsize) {
+static bool Send(const void *output, size_t outputsize) {
   int rc, have;
   static bool once;
   static z_stream zs;
@@ -326,11 +328,17 @@ static void Send(const void *output, size_t outputsize) {
     rc = deflate(&zs, Z_SYNC_FLUSH);
     CHECK_NE(Z_STREAM_ERROR, rc);
     have = sizeof(zbuf) - zs.avail_out;
-    CHECK_EQ(have, mbedtls_ssl_write(&ezssl, zbuf, have));
+    rc = mbedtls_ssl_write(&ezssl, zbuf, have);
+    if (rc == MBEDTLS_ERR_NET_CONN_RESET) {
+      usleep((g_backoff = (g_backoff + 1000) * 2));
+      return false;
+    }
+    CHECK_EQ(have, rc);
   } while (!zs.avail_out);
+  return true;
 }
 
-void SendRequest(void) {
+int SendRequest(void) {
   int fd;
   char *p;
   size_t i;
@@ -357,22 +365,30 @@ void SendRequest(void) {
   q = mempcpy(q, name, namesize);
   assert(hdrsize == q - hdr);
   DEBUGF("running %s on %s", g_prog, g_hostname);
-  Send(hdr, hdrsize);
-  Send(p, progsize);
-  CHECK_EQ(0, EzTlsFlush(&ezbio, 0, 0));
+  if (Send(hdr, hdrsize) && Send(p, progsize)) {
+    if (!(rc = EzTlsFlush(&ezbio, 0, 0))) {
+      rc = 0;
+    } else if (rc == MBEDTLS_ERR_NET_CONN_RESET) {
+      rc = -1;
+    } else {
+      CHECK_EQ(0, rc);
+    }
+  } else {
+    rc = -1;
+  }
   CHECK_NE(-1, munmap(p, st.st_size));
   CHECK_NE(-1, close(fd));
+  return rc;
 }
 
 bool Recv(unsigned char *p, size_t n) {
   size_t i, rc;
-  static long backoff;
   for (i = 0; i < n; i += rc) {
     do {
       rc = mbedtls_ssl_read(&ezssl, p + i, n - i);
     } while (rc == MBEDTLS_ERR_SSL_WANT_READ);
     if (!rc || rc == MBEDTLS_ERR_NET_CONN_RESET) {
-      usleep((backoff = (backoff + 1000) * 2));
+      usleep((g_backoff = (g_backoff + 1000) * 2));
       return false;
     } else if (rc < 0) {
       TlsDie("read response failed", rc);
@@ -442,8 +458,7 @@ int RunOnHost(char *spec) {
       WARNF("warning: got connection reset in handshake");
       close(g_sock);
     }
-    SendRequest();
-  } while ((rc = ReadResponse()) == -1);
+  } while ((rc = SendRequest()) == -1 || (rc = ReadResponse()) == -1);
   return rc;
 }
 

tool/build/runitd.c

@@ -42,6 +42,7 @@
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/poll.h"
 #include "libc/sysv/consts/sa.h"
+#include "libc/sysv/consts/sig.h"
 #include "libc/sysv/consts/so.h"
 #include "libc/sysv/consts/sock.h"
 #include "libc/sysv/consts/sol.h"
@@ -110,7 +111,12 @@ void OnInterrupt(int sig) {
 
 void OnChildTerminated(int sig) {
   int ws, pid;
+  sigset_t ss, oldss;
+  sigfillset(&ss);
+  sigdelset(&ss, SIGTERM);
+  sigprocmask(SIG_BLOCK, &ss, &oldss);
   for (;;) {
+    INFOF("waitpid");
     if ((pid = waitpid(-1, &ws, WNOHANG)) != -1) {
       if (pid) {
         if (WIFEXITED(ws)) {
@@ -127,6 +133,7 @@ void OnChildTerminated(int sig) {
       FATALF("waitpid failed in sigchld");
     }
   }
+  sigprocmask(SIG_SETMASK, &oldss, 0);
 }
 
 wontreturn void ShowUsage(FILE *f, int rc) {
@@ -229,6 +236,7 @@ void SendExitMessage(int rc) {
   msg[0 + 3] = (RUNITD_MAGIC & 0x000000ff) >> 000;
   msg[4] = kRunitExit;
   msg[5] = rc;
+  INFOF("mbedtls_ssl_write");
   CHECK_EQ(sizeof(msg), mbedtls_ssl_write(&ezssl, msg, sizeof(msg)));
   CHECK_EQ(0, EzTlsFlush(&ezbio, 0, 0));
 }
@@ -247,6 +255,7 @@ void SendOutputFragmentMessage(enum RunitCommand kind, unsigned char *buf,
   msg[5 + 1] = (size & 0x00ff0000) >> 020;
   msg[5 + 2] = (size & 0x0000ff00) >> 010;
   msg[5 + 3] = (size & 0x000000ff) >> 000;
+  INFOF("mbedtls_ssl_write");
   CHECK_EQ(sizeof(msg), mbedtls_ssl_write(&ezssl, msg, sizeof(msg)));
   while (size) {
     CHECK_NE(-1, (rc = mbedtls_ssl_write(&ezssl, buf, size)));
@@ -294,6 +303,7 @@ void Recv(void *output, size_t outputsize) {
     // get another fixed-size data packet from network
     // pass along error conditions to caller
     // pass along eof condition to zlib
+    INFOF("mbedtls_ssl_read");
     received = mbedtls_ssl_read(&ezssl, buf, sizeof(buf));
     if (received < 0) TlsDie("read failed", received);
     // decompress packet completely
@@ -347,12 +357,14 @@ void HandleClient(void) {
 
   /* read request to run program */
   addrsize = sizeof(addr);
+  INFOF("accept");
   CHECK_NE(-1, (g_clifd = accept4(g_servfd, &addr, &addrsize, SOCK_CLOEXEC)));
   if (fork()) {
     close(g_clifd);
     return;
   }
   EzFd(g_clifd);
+  INFOF("EzHandshake");
   EzHandshake();
   addrstr = gc(DescribeAddress(&addr));
   DEBUGF("%s %s %s", gc(DescribeAddress(&g_servaddr)), "accepted", addrstr);
@@ -376,6 +388,7 @@ void HandleClient(void) {
   }
   CHECK_NE(-1, (g_exefd = creat(g_exepath, 0700)));
   LOGIFNEG1(ftruncate(g_exefd, filesize));
+  INFOF("xwrite");
   CHECK_NE(-1, xwrite(g_exefd, exe, filesize));
   LOGIFNEG1(close(g_exefd));
 
@@ -425,6 +438,7 @@ void HandleClient(void) {
     fds[0].events = POLLIN;
     fds[1].fd = pipefds[0];
     fds[1].events = POLLIN;
+    INFOF("poll");
     events = poll(fds, ARRAYLEN(fds), (deadline - now) * 1000);
     CHECK_NE(-1, events);  // EINTR shouldn't be possible
     if (fds[0].revents) {
@@ -440,6 +454,7 @@ void HandleClient(void) {
       LOGIFNEG1(unlink(g_exepath));
       _exit(1);
     }
+    INFOF("read");
     got = read(pipefds[0], g_buf, sizeof(g_buf));
     CHECK_NE(-1, got);  // EINTR shouldn't be possible
     if (!got) {
@@ -449,6 +464,7 @@ void HandleClient(void) {
     fwrite(g_buf, got, 1, stderr);
     SendOutputFragmentMessage(kRunitStderr, g_buf, got);
   }
+  INFOF("waitpid");
   CHECK_NE(-1, waitpid(child, &wstatus, 0));  // EINTR shouldn't be possible
   if (WIFEXITED(wstatus)) {
     if (WEXITSTATUS(wstatus)) {
@@ -463,6 +479,7 @@ void HandleClient(void) {
   }
   LOGIFNEG1(unlink(g_exepath));
   SendExitMessage(exitcode);
+  INFOF("mbedtls_ssl_close_notify");
   mbedtls_ssl_close_notify(&ezssl);
   LOGIFNEG1(close(g_clifd));
   _exit(0);
@@ -524,7 +541,7 @@ void Daemonize(void) {
 int main(int argc, char *argv[]) {
   int i;
   SetupPresharedKeySsl(MBEDTLS_SSL_IS_SERVER, GetRunitPsk());
-  /* __log_level = kLogDebug; */
+  __log_level = kLogInfo;
   GetOpts(argc, argv);
   for (i = 3; i < 16; ++i) close(i);
   errno = 0;

tool/emacs/cosmo-asm-mode.el

@@ -108,6 +108,7 @@
        "protip"
        "nxbitsafe"
        "vforksafe"
+       "threadsafe"
        "preinitsafe"
        "asyncsignalsafe"
        "notasyncsignalsafe"

tool/net/redbean.c

@@ -146,6 +146,7 @@
 #include "third_party/mbedtls/iana.h"
 #include "third_party/mbedtls/md.h"
 #include "third_party/mbedtls/md5.h"
+#include "third_party/mbedtls/net_sockets.h"
 #include "third_party/mbedtls/oid.h"
 #include "third_party/mbedtls/pk.h"
 #include "third_party/mbedtls/rsa.h"

tool/net/wb.c

@@ -52,6 +52,7 @@
 #include "third_party/mbedtls/ctr_drbg.h"
 #include "third_party/mbedtls/debug.h"
 #include "third_party/mbedtls/error.h"
+#include "third_party/mbedtls/net_sockets.h"
 #include "third_party/mbedtls/ssl.h"
 
 #define OPTS "BIqksvzX:H:C:m:"