util: Wrap faccessat() to fix some portability issues

4 files changed, 21 insertions, 2 deletions

diff --git a/color.c b/color.c
index 031741d..8df6a1f 100644
--- a/color.c
+++ b/color.c
@@ -351,7 +351,7 @@ static const char *file_color(const struct colors *colors, const char *filename,
 		break;
 
 	case S_IFLNK:
-		if (faccessat(ftwbuf->at_fd, ftwbuf->at_path, F_OK, AT_EACCESS) == 0) {
+		if (xfaccessat(ftwbuf->at_fd, ftwbuf->at_path, F_OK) == 0) {
 			color = colors->link;
 		} else {
 			color = colors->orphan;
diff --git a/eval.c b/eval.c
index 08d2643..8c7af85 100644
--- a/eval.c
+++ b/eval.c
@@ -131,7 +131,7 @@ bool eval_false(const struct expr *expr, struct eval_state *state) {
  */
 bool eval_access(const struct expr *expr, struct eval_state *state) {
 	struct BFTW *ftwbuf = state->ftwbuf;
-	return faccessat(ftwbuf->at_fd, ftwbuf->at_path, expr->idata, AT_EACCESS) == 0;
+	return xfaccessat(ftwbuf->at_fd, ftwbuf->at_path, expr->idata) == 0;
 }
 
 /**
diff --git a/util.c b/util.c
index bdb3620..0e7ec60 100644
--- a/util.c
+++ b/util.c
@@ -226,6 +226,20 @@ const char *xbasename(const char *path) {
 	return i;
 }
 
+int xfaccessat(int fd, const char *path, int amode) {
+	int ret = faccessat(fd, path, amode, 0);
+
+#ifdef AT_EACCESS
+	// Some platforms, like Hurd, only support AT_EACCESS.  Other platforms,
+	// like Android, don't support AT_EACCESS at all.
+	if (ret != 0 && (errno == EINVAL || errno == ENOTSUP)) {
+		ret = faccessat(fd, path, amode, AT_EACCESS);
+	}
+#endif
+
+	return ret;
+}
+
 bool is_nonexistence_error(int error) {
 	return error == ENOENT || errno == ENOTDIR;
 }
diff --git a/util.h b/util.h
index 57123e0..8f285d3 100644
--- a/util.h
+++ b/util.h
@@ -143,6 +143,11 @@ void format_mode(mode_t mode, char str[11]);
 const char *xbasename(const char *path);
 
 /**
+ * Wrapper for faccessat() that handles some portability issues.
+ */
+int xfaccessat(int fd, const char *path, int amode);
+
+/**
  * Return whether an error code is due to a path not existing.
  */
 bool is_nonexistence_error(int error);