From eaca5b3e81940472a78c3698ef341d553233e006 Mon Sep 17 00:00:00 2001
From: Justine Tunney <jtunney@gmail.com>
Date: Fri, 29 Jan 2021 21:46:23 -0800
Subject: [PATCH] Add exponential backoff to rmdir() on Windows

---
 libc/calls/chdir-nt.c        |  5 +++--
 libc/calls/hefty/dirstream.c |  6 ++----
 libc/calls/rmdir-nt.c        | 31 +++++++++++++++++++++++++------
 libc/calls/touch.c           |  1 -
 libc/sysv/consts.sh          |  2 +-
 libc/sysv/consts/ENOTEMPTY.s |  2 +-
 libc/x/rmrf.c                |  7 ++++++-
 7 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/libc/calls/chdir-nt.c b/libc/calls/chdir-nt.c
index 36767025b..86ec65a00 100644
--- a/libc/calls/chdir-nt.c
+++ b/libc/calls/chdir-nt.c
@@ -25,8 +25,9 @@ textwindows int chdir$nt(const char *path) {
   int len;
   char16_t path16[PATH_MAX];
   if ((len = __mkntpath(path, path16)) == -1) return -1;
-  if (path16[len - 1] != u'/' && path16[len - 1] != u'\\') {
-    path16[len + 0] = u'/';
+  if (path16[len - 1] != u'\\') {
+    if (len + 1 + 1 > PATH_MAX) return enametoolong();
+    path16[len + 0] = u'\\';
     path16[len + 1] = u'\0';
   }
   if (SetCurrentDirectory(path16)) {
diff --git a/libc/calls/hefty/dirstream.c b/libc/calls/hefty/dirstream.c
index 5f835e223..8632e1574 100644
--- a/libc/calls/hefty/dirstream.c
+++ b/libc/calls/hefty/dirstream.c
@@ -92,10 +92,8 @@ static textwindows noinline DIR *opendir$nt(const char *name) {
   char16_t name16[PATH_MAX];
   if ((len = __mkntpath(name, name16)) == -1) return NULL;
   if (len + 2 + 1 > PATH_MAX) return PROGN(enametoolong(), NULL);
-  if (name16[len - 1] == u'/' || name16[len - 1] == u'\\') {
-    name16[--len] = u'\0';
-  }
-  name16[len++] = u'/';
+  while (name16[len - 1] == u'\\') name16[--len] = u'\0';
+  name16[len++] = u'\\';
   name16[len++] = u'*';
   name16[len] = u'\0';
   if (!(res = calloc(1, sizeof(DIR)))) return NULL;
diff --git a/libc/calls/rmdir-nt.c b/libc/calls/rmdir-nt.c
index 92ea7563f..bf2d625db 100644
--- a/libc/calls/rmdir-nt.c
+++ b/libc/calls/rmdir-nt.c
@@ -17,15 +17,34 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/internal.h"
+#include "libc/nt/errors.h"
 #include "libc/nt/files.h"
 #include "libc/nt/runtime.h"
+#include "libc/nt/synchronization.h"
+#include "libc/sysv/errfuns.h"
 
 textwindows int rmdir$nt(const char *path) {
-  uint16_t path16[PATH_MAX];
-  if (__mkntpath(path, path16) == -1) return -1;
-  if (RemoveDirectory(path16)) {
-    return 0;
-  } else {
-    return __winerr();
+  int e, ms, len;
+  char16_t path16[PATH_MAX];
+  if ((len = __mkntpath(path, path16)) == -1) return -1;
+  while (path16[len - 1] == u'\\') path16[--len] = u'\0';
+  if (len + 2 + 1 > PATH_MAX) return enametoolong();
+  for (ms = 1;; ms *= 2) {
+    if (RemoveDirectory(path16)) return 0;
+    /*
+     * Files can linger, for absolutely no reason.
+     * Possibly some Windows Defender bug on Win7.
+     * Sleep for up to one second w/ expo backoff.
+     * Alternative is use Microsoft internal APIs.
+     * Never could have imagined it'd be this bad.
+     */
+    if ((e = GetLastError()) == kNtErrorDirNotEmpty && ms <= 512) {
+      Sleep(ms);
+      continue;
+    } else {
+      break;
+    }
   }
+  errno = e;
+  return -1;
 }
diff --git a/libc/calls/touch.c b/libc/calls/touch.c
index 526644341..f3b32fc14 100644
--- a/libc/calls/touch.c
+++ b/libc/calls/touch.c
@@ -30,6 +30,5 @@
 int touch(const char *file, uint32_t mode) {
   int fd;
   if ((fd = open(file, O_CREAT | O_WRONLY, mode)) == -1) return -1;
-  fsync(fd); /* TODO(jart): do we need it? */
   return close(fd);
 }
diff --git a/libc/sysv/consts.sh b/libc/sysv/consts.sh
index 1acb9694d..1dd6339ed 100755
--- a/libc/sysv/consts.sh
+++ b/libc/sysv/consts.sh
@@ -63,7 +63,7 @@ syscon	errno	ERANGE					34			34			34			34			-1			# bsd consensus
 syscon	errno	EDEADLK					35			11			11			11			1131			# bsd consensus & kNtErrorPossibleDeadlock
 syscon	errno	ENAMETOOLONG				36			63			63			63			0x274f			# bsd consensus & WSAENAMETOOLONG
 syscon	errno	ENOLCK					37			77			77			77			-1			# bsd consensus
-syscon	errno	ENOTEMPTY				39			66			66			66			0x2752			# bsd consensus & WSAENOTEMPTY
+syscon	errno	ENOTEMPTY				39			66			66			66			145			# bsd consensus & kNtErrorDirNotEmpty (TODO: What is WSAENOTEMPTY? 0x2752)
 syscon	errno	ELOOP					40			62			62			62			0x274e			# bsd consensus & WSAELOOP
 syscon	errno	ENOMSG					42			91			83			90			-1
 syscon	errno	EIDRM					43			90			82			89			-1
diff --git a/libc/sysv/consts/ENOTEMPTY.s b/libc/sysv/consts/ENOTEMPTY.s
index 9d069b870..d806960f0 100644
--- a/libc/sysv/consts/ENOTEMPTY.s
+++ b/libc/sysv/consts/ENOTEMPTY.s
@@ -1,2 +1,2 @@
 .include "libc/sysv/consts/syscon.inc"
-.syscon errno ENOTEMPTY 39 66 66 66 0x2752
+.syscon errno ENOTEMPTY 39 66 66 66 145
diff --git a/libc/x/rmrf.c b/libc/x/rmrf.c
index 849f88f44..cbf16fd69 100644
--- a/libc/x/rmrf.c
+++ b/libc/x/rmrf.c
@@ -37,7 +37,12 @@ static int rmrfdir(const char *dirpath) {
     if (!strcmp(e->d_name, "..")) continue;
     if (strchr(e->d_name, '/')) abort();
     path = xjoinpaths(dirpath, e->d_name);
-    if ((e->d_type == DT_DIR ? rmrfdir(path) : unlink(path)) == -1) {
+    if (e->d_type == DT_DIR) {
+      rc = rmrfdir(path);
+    } else {
+      rc = unlink(path);
+    }
+    if (rc == -1) {
       free(path);
       closedir(d);
       return -1;