Make improvements

- Document redbean's argon2 module
- Fix regressions in cthreads library
- Make testlib work better with threads
- Give the cthreads library lots of love
- Remove some of the stdio assembly code
- Implement getloadavg() across platforms
- Code size optimizations for errnos, etc.
- Only check for signals in main thread on Windows
- Make errnos for dup2 / dup3 consistent with posix

This change also fixes a bug in the argon2 module, where the NUL
terminator was being included in the hash encoded ascii string. This
shouldn't require any database migrations to folks who found this module
and productionized it, since the argon2 library treats it as a c string.

libc/thread/init.c

@@ -16,59 +16,59 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
 #include "libc/calls/calls.h"
-#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/macros.internal.h"
+#include "libc/nexgen32e/threaded.h"
+#include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
+#include "libc/runtime/stack.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/map.h"
-#include "libc/sysv/consts/nr.h"
 #include "libc/sysv/consts/prot.h"
 #include "libc/thread/descriptor.h"
-
-// TLS boundaries
-extern char _tbss_start, _tbss_end, _tdata_start, _tdata_end;
+#include "libc/thread/self.h"
 
 static textstartup void _main_thread_init(void) {
-  if (!IsLinux()) return; /* TODO */
-  size_t tbsssize = &_tbss_end - &_tbss_start;
-  size_t tdatasize = &_tdata_end - &_tdata_start;
-  size_t tlssize = tbsssize + tdatasize;
-  size_t totalsize = tlssize + sizeof(struct cthread_descriptor_t);
-  totalsize = (totalsize + PAGESIZE - 1) & -PAGESIZE;
+  _Static_assert(offsetof(struct cthread_descriptor_t, self) == 0x00, "");
+  _Static_assert(offsetof(struct cthread_descriptor_t, self2) == 0x30, "");
+  _Static_assert(offsetof(struct cthread_descriptor_t, tid) == 0x38, "");
+  _Static_assert(offsetof(struct cthread_descriptor_t, err) == 0x3c, "");
+  cthread_t td;
+  size_t totalsize;
+  char *mem, *bottom, *top;
 
-  uintptr_t mem = (uintptr_t)mmap(NULL, totalsize, PROT_READ | PROT_WRITE,
-                                  MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-  if (mem == -1) {
-    abort();
-  }
+  totalsize = ROUNDUP(
+      (uintptr_t)_tls_size + sizeof(struct cthread_descriptor_t), FRAMESIZE);
 
-  void* bottom = (void*)mem;
-  void* top = (void*)(mem + totalsize);
+  mem = mmap(0, totalsize, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE,
+             -1, 0);
+  assert(mem != MAP_FAILED);
 
-  cthread_t td = (cthread_t)top - 1;
+  bottom = mem;
+  top = mem + totalsize;
+
+  td = (cthread_t)(top - sizeof(struct cthread_descriptor_t));
   td->self = td;
-  td->stack.top = NULL;
-  td->stack.bottom = NULL;
-  td->tls.top = top;
-  td->tls.bottom = bottom;
-  td->alloc.top = top;
+  td->self2 = td;
+  td->err = errno;
+  td->tid = gettid();
   td->alloc.bottom = bottom;
+  td->alloc.top = top;
+  td->stack.bottom = GetStackAddr(0);
+  td->stack.top = td->stack.bottom + GetStackSize();
   td->state = cthread_main;
 
   // Initialize TLS with content of .tdata section
-  memmove((void*)((uintptr_t)td - tlssize), &_tdata_start, tdatasize);
-
-  // Get TID of main thread
-  int gettid = __NR_gettid;
-  if (gettid == 0xfff) gettid = __NR_getpid;
-  td->tid = syscall(gettid);
+  memmove((void *)((uintptr_t)td - (uintptr_t)_tls_size), _tdata_start,
+          (uintptr_t)_tdata_size);
 
   // Set FS
-  if (arch_prctl(ARCH_SET_FS, td) != 0) {
-    abort();
-  }
+  __install_tls((char *)td);
+  assert(cthread_self()->tid == gettid());
 }
 
-const void* const _main_thread_ctor[] initarray = {
+const void *const _main_thread_ctor[] initarray = {
     _main_thread_init,
 };