Linux-libre 4.8.2-gnupck-4.8.2-gnu

1 files changed, 26 insertions, 0 deletions

diff --git a/tools/lib/str_error_r.c b/tools/lib/str_error_r.c
new file mode 100644
index 000000000..503ae0722
--- /dev/null
+++ b/tools/lib/str_error_r.c
@@ -0,0 +1,26 @@
+#undef _GNU_SOURCE
+#include <string.h>
+#include <stdio.h>
+#include <linux/string.h>
+
+/*
+ * The tools so far have been using the strerror_r() GNU variant, that returns
+ * a string, be it the buffer passed or something else.
+ *
+ * But that, besides being tricky in cases where we expect that the function
+ * using strerror_r() returns the error formatted in a provided buffer (we have
+ * to check if it returned something else and copy that instead), breaks the
+ * build on systems not using glibc, like Alpine Linux, where musl libc is
+ * used.
+ *
+ * So, introduce yet another wrapper, str_error_r(), that has the GNU
+ * interface, but uses the portable XSI variant of strerror_r(), so that users
+ * rest asured that the provided buffer is used and it is what is returned.
+ */
+char *str_error_r(int errnum, char *buf, size_t buflen)
+{
+	int err = strerror_r(errnum, buf, buflen);
+	if (err)
+		snprintf(buf, buflen, "INTERNAL ERROR: strerror_r(%d, %p, %zd)=%d", errnum, buf, buflen, err);
+	return buf;
+}