From 925b435faf6c5c3971b74c00298f3dd679256d3d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timo=20Ter=C3=A4s?= <timo.teras@iki.fi>
Date: Mon, 21 Mar 2022 13:04:36 +0200
Subject: [PATCH] portability: add qsort_r

---
 portability/meson.build |  1 +
 portability/qsort_r.c   | 26 ++++++++++++++++++++++++++
 portability/stdlib.h    |  7 +++++++
 3 files changed, 34 insertions(+)
 create mode 100644 portability/qsort_r.c
 create mode 100644 portability/stdlib.h

diff --git a/portability/meson.build b/portability/meson.build
index ae8f6bc..d077345 100644
--- a/portability/meson.build
+++ b/portability/meson.build
@@ -9,6 +9,7 @@ check_functions = [
 	['strlcpy', 'strlcpy.c', 'NEED_STRLCPY', 'string.h'],
 	['pipe2', 'pipe2.c', 'NEED_PIPE2', 'unistd.h'],
 	['mknodat', 'mknodat.c', 'NEED_MKNODAT', 'sys/stat.h'],
+	['qsort_r', 'qsort_r.c', 'NEED_QSORT_R', 'stdlib.h'],
 ]
 
 
diff --git a/portability/qsort_r.c b/portability/qsort_r.c
new file mode 100644
index 0000000..7c5df27
--- /dev/null
+++ b/portability/qsort_r.c
@@ -0,0 +1,26 @@
+#include <stdlib.h>
+
+struct qsortr_ctx {
+	int (*compar)(const void *, const void *, void *);
+	void *arg;
+};
+
+static __thread struct qsortr_ctx *__ctx;
+
+static int cmp_wrapper(const void *a, const void *b)
+{
+	return __ctx->compar(a, b, __ctx->arg);
+}
+
+void qsort_r(void *base, size_t nmemb, size_t size,
+	int (*compar)(const void *, const void *, void *),
+	void *arg)
+{
+	struct qsortr_ctx ctx = {
+		.compar = compar,
+		.arg = arg,
+	};
+	__ctx = &ctx;
+	qsort(base, nmemb, size, cmp_wrapper);
+	__ctx = 0;
+}
diff --git a/portability/stdlib.h b/portability/stdlib.h
new file mode 100644
index 0000000..6254c7c
--- /dev/null
+++ b/portability/stdlib.h
@@ -0,0 +1,7 @@
+#include_next <stdlib.h>
+
+#ifdef NEED_QSORT_R
+void qsort_r(void *base, size_t nmemb, size_t size,
+	int (*compar)(const void *, const void *, void *),
+	void *arg);
+#endif