bfstd: New {error,errno}_is_like() functions

We used to have is_nonexistence_error() to consistently treat ENOENT and
ENOTDIR the same.  Recently, we started considering EFAULT the same as
ENAMETOOLONG on DragonFly BSD to work around a kernel bug.  Unify both
of these behind a more generic interface.

1 files changed, 21 insertions, 2 deletions

diff --git a/src/bfstd.c b/src/bfstd.c
index c0e61cb..15e8667 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -36,8 +36,27 @@
 #  include <util.h>
 #endif
 
-bool is_nonexistence_error(int error) {
-	return error == ENOENT || errno == ENOTDIR;
+bool error_is_like(int error, int category) {
+	if (error == category) {
+		return true;
+	}
+
+	switch (category) {
+	case ENOENT:
+		return error == ENOTDIR;
+
+#if __DragonFly__
+	// https://twitter.com/tavianator/status/1742991411203485713
+	case ENAMETOOLONG:
+		return error == EFAULT;
+#endif
+	}
+
+	return false;
+}
+
+bool errno_is_like(int category) {
+	return error_is_like(errno, category);
 }
 
 char *xdirname(const char *path) {