Fix race condition in makedirs()

libc/x/makedirs.c

@@ -16,11 +16,11 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/intrin/safemacros.internal.h"
-#include "libc/intrin/weaken.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/strace.internal.h"
 #include "libc/errno.h"
+#include "libc/intrin/safemacros.internal.h"
+#include "libc/intrin/weaken.h"
 #include "libc/mem/mem.h"
 #include "libc/str/str.h"
 #include "libc/x/x.h"
@@ -44,7 +44,12 @@ static int MakeDirs(const char *path, unsigned mode, int e) {
   free(dir);
   if (rc == -1) return -1;
   errno = e;
-  return mkdir(path, mode);
+  if (!mkdir(path, mode) || errno == EEXIST) {
+    errno = e;
+    return 0;
+  } else {
+    return -1;
+  }
 }
 
 /**
@@ -55,7 +60,7 @@ static int MakeDirs(const char *path, unsigned mode, int e) {
  * @param path is a UTF-8 string, preferably relative w/ forward slashes
  * @param mode can be, for example, 0755
  * @return 0 on success or -1 w/ errno
- * @see mkdir()
+ * @threadsafe
  */
 int makedirs(const char *path, unsigned mode) {
   return MakeDirs(path, mode, errno);

libc/x/xbasename.c

@@ -17,6 +17,7 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/fmt/conv.h"
+#include "libc/mem/mem.h"
 #include "libc/runtime/gc.internal.h"
 #include "libc/x/x.h"
 
@@ -24,5 +25,9 @@
  * Returns base portion of path.
  */
 char *xbasename(const char *path) {
-  return xstrdup(basename(gc(xstrdup(path))));
+  char *base;
+  path = xstrdup(path);
+  base = xstrdup(basename(path));
+  free(path);
+  return base;
 }

libc/x/xdirname.c

@@ -17,12 +17,16 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/fmt/conv.h"
-#include "libc/runtime/gc.internal.h"
+#include "libc/mem/mem.h"
 #include "libc/x/x.h"
 
 /**
  * Returns directory portion of path.
  */
 char *xdirname(const char *path) {
-  return xstrdup(dirname(gc(xstrdup(path))));
+  char *dirp;
+  path = xstrdup(path);
+  dirp = xstrdup(dirname(path));
+  free(path);
+  return dirp;
 }