Overhaul process spawning

libc/runtime/cocmd.c

@@ -155,6 +155,11 @@ static char *Finish(void) {
   }
 }
 
+static int Pause(void) {
+  pause();
+  return 0;
+}
+
 static int True(void) {
   return 0;
 }
@@ -671,6 +676,7 @@ static int TryBuiltin(void) {
   if (!strcmp(args[0], "true")) return True();
   if (!strcmp(args[0], "test")) return Test();
   if (!strcmp(args[0], "kill")) return Kill();
+  if (!strcmp(args[0], "pause")) return Pause();
   if (!strcmp(args[0], "flock")) return Flock();
   if (!strcmp(args[0], "chmod")) return Chmod();
   if (!strcmp(args[0], "touch")) return Touch();

libc/runtime/login_tty.c

@@ -16,9 +16,11 @@
 │ 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/calls/syscall-sysv.internal.h"
 #include "libc/dce.h"
+#include "libc/errno.h"
 #include "libc/intrin/strace.internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/utmp.h"
@@ -28,23 +30,37 @@
 /**
  * Prepares terminal for login.
  *
+ * After this operation `fd` will be used for all stdio handles.
+ *
  * @return 0 on success, or -1 w/ errno
+ * @raise EPERM if terminal is already controlling another sid?
+ * @raise EPERM if pledge() was used without tty
+ * @raise ENOTTY if `fd` isn't a teletypewriter
  * @raise ENOSYS on Windows and Metal
- * @raise EPERM if terminal is already controlling another sid
+ * @raise EBADF if `fd` isn't open
  */
 int login_tty(int fd) {
-  int i, rc;
-  if (IsLinux() || IsBsd()) {
-    setsid();
-    if (!sys_ioctl(fd, TIOCSCTTY, 0)) {
-      for (i = 0; i < 3; ++i) dup2(fd, i);
-      if (fd > 2) close(fd);
-      rc = 0;
-    } else {
-      rc = -1;
-    }
-  } else {
+  int rc;
+  if (!IsLinux() && !IsBsd()) {
     rc = enosys();
+  } else if (!isatty(fd)) {
+    rc = -1;  // validate before changing the process's state
+  } else {
+    // become session leader
+    // we don't care if it fails due to already being the one
+    int e = errno;
+    sys_setsid();
+    errno = e;
+    // take control of teletypewriter (requires being leader)
+    if ((rc = sys_ioctl(fd, TIOCSCTTY, 0)) != -1) {
+      unassert(!sys_dup2(fd, 0, 0));
+      unassert(!sys_dup2(fd, 1, 0));
+      unassert(!sys_dup2(fd, 2, 0));
+      if (fd > 2) {
+        unassert(!sys_close(fd));
+      }
+      rc = 0;
+    }
   }
   STRACE("login_tty(%d) → %d% m", fd, rc);
   return rc;

libc/runtime/runtime.mk

@@ -76,6 +76,7 @@ o/$(MODE)/libc/runtime/ftracer.o: private		\
 
 o/$(MODE)/libc/runtime/cosmo2.o				\
 o/$(MODE)/libc/runtime/fork-nt.o			\
+o/$(MODE)/libc/runtime/enable_tls.o			\
 o/$(MODE)/libc/runtime/printmemoryintervals.o		\
 o/$(MODE)/libc/runtime/findmemoryinterval.o		\
 o/$(MODE)/libc/runtime/sys_mprotect.greg.o		\
@@ -92,6 +93,7 @@ o/$(MODE)/libc/runtime/print.greg.o			\
 o/$(MODE)/libc/runtime/stackchkfail.o			\
 o/$(MODE)/libc/runtime/stackchkfaillocal.o		\
 o/$(MODE)/libc/runtime/winmain.greg.o			\
+o/$(MODE)/libc/runtime/interceptflag.greg.o		\
 o/$(MODE)/libc/runtime/opensymboltable.o: private	\
 		CFLAGS +=				\
 			-Os				\

libc/runtime/stackuse.c

@@ -60,7 +60,8 @@ static textexit void LogStackUse(void) {
   if (!PLEDGED(STDIO) || !PLEDGED(WPATH) || !PLEDGED(CPATH)) return;
   usage = GetStackUsage((char *)GetStackAddr(), GetStackSize());
   e = errno;
-  if ((fd = open(stacklog, O_APPEND | O_CREAT | O_WRONLY, 0644)) != -1) {
+  if ((fd = open(stacklog, O_APPEND | O_CREAT | O_WRONLY | O_CLOEXEC, 0644)) !=
+      -1) {
     p = FormatUint64(stacklog, usage);
     for (i = 0; i < __argc; ++i) {
       n = strlen(__argv[i]);

libc/runtime/winmain.greg.c

@@ -21,6 +21,8 @@
 #include "libc/calls/state.internal.h"
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/dce.h"
+#include "libc/intrin/asan.internal.h"
+#include "libc/intrin/asancodes.h"
 #include "libc/intrin/describeflags.internal.h"
 #include "libc/intrin/getenv.internal.h"
 #include "libc/intrin/weaken.h"
@@ -176,6 +178,27 @@ __msabi static textwindows wontreturn void WinInit(const char16_t *cmdline) {
   struct WinArgs *wa =
       (struct WinArgs *)(stackaddr + (stacksize - sizeof(struct WinArgs)));
 
+  // allocate asan memory if needed
+  if (IsAsan()) {
+    uintptr_t shadowaddr = 0x7fff8000 + (stackaddr >> 3);
+    uintptr_t shadowend = 0x7fff8000 + ((stackaddr + stacksize) >> 3);
+    uintptr_t shallocaddr = ROUNDDOWN(shadowaddr, FRAMESIZE);
+    uintptr_t shallocend = ROUNDUP(shadowend, FRAMESIZE);
+    uintptr_t shallocsize = shallocend - shallocaddr;
+    __imp_MapViewOfFileEx(
+        (_mmi.p[1].h =
+             __imp_CreateFileMappingW(-1, &kNtIsInheritable, kNtPageReadwrite,
+                                      shallocsize >> 32, shallocsize, NULL)),
+        kNtFileMapWrite, 0, 0, shallocsize, (void *)shallocaddr);
+    _mmi.p[1].x = shallocaddr >> 16;
+    _mmi.p[1].y = (shallocaddr >> 16) + ((shallocsize - 1) >> 16);
+    _mmi.p[1].prot = PROT_READ | PROT_WRITE;
+    _mmi.p[1].flags = 0x00000022;  // private+anonymous
+    _mmi.p[1].size = shallocsize;
+    _mmi.i = 2;
+    __asan_poison((void *)stackaddr, GetGuardSize(), kAsanStackOverflow);
+  }
+
   // parse utf-16 command into utf-8 argv array in argument block
   int count = GetDosArgv(cmdline, wa->argblock, ARRAYLEN(wa->argblock),
                          wa->argv, ARRAYLEN(wa->argv));
@@ -231,13 +254,13 @@ __msabi textwindows int64_t WinMain(int64_t hInstance, int64_t hPrevInstance,
   // sloppy flag-only check for early initialization
   if (__strstr16(cmdline, u"--strace")) ++__strace;
 #endif
+  if (_weaken(WinSockInit)) {
+    _weaken(WinSockInit)();
+  }
   DeduplicateStdioHandles();
   if (_weaken(WinMainStdin)) {
     _weaken(WinMainStdin)();
   }
-  if (_weaken(WinSockInit)) {
-    _weaken(WinSockInit)();
-  }
   if (_weaken(WinMainForked)) {
     _weaken(WinMainForked)();
   }