[RFC PATCH 3/7] vfio: selftests: Allow multiple BDFs in VFIO_SELFTESTS_BDF

[David Matlack <dmatlack@google.com>]

Parse whitespace-separated PCI BDFs from VFIO_SELFTESTS_BDF in
vfio_selftests_get_bdfs() instead of requiring a single BDF.

Multi-device tests such as P2P DMA tests need two or more devices even
when invoked through run_kselftest.sh without command-line arguments.
Single-device callers using vfio_selftests_get_bdf() continue to receive
the first BDF.

Signed-off-by: David Matlack <dmatlack@google.com>
---
 tools/testing/selftests/vfio/lib/libvfio.c | 53 ++++++++++++++++------
 1 file changed, 39 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/vfio/lib/libvfio.c b/tools/testing/selftests/vfio/lib/libvfio.c
index 3a3d1ed635c1..448d11442b53 100644
--- a/tools/testing/selftests/vfio/lib/libvfio.c
+++ b/tools/testing/selftests/vfio/lib/libvfio.c
@@ -2,6 +2,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/mman.h>
 
 #include <linux/align.h>
@@ -32,38 +33,62 @@ static char **get_bdfs_cmdline(int *argc, char *argv[], int *nr_bdfs)
 	return *nr_bdfs ? &argv[i] : NULL;
 }
 
-static char *get_bdf_env(void)
+static char **get_bdfs_env(int *nr_bdfs)
 {
-	char *bdf;
+	static char **bdfs;
+	static int count;
+	char *env, *tok, *saveptr;
+	int cap = 0;
 
-	bdf = getenv("VFIO_SELFTESTS_BDF");
-	if (!bdf)
+	if (bdfs) {
+		*nr_bdfs = count;
+		return bdfs;
+	}
+
+	env = getenv("VFIO_SELFTESTS_BDF");
+	if (!env)
 		return NULL;
 
-	VFIO_ASSERT_TRUE(is_bdf(bdf), "Invalid BDF: %s\n", bdf);
-	return bdf;
+	env = strdup(env);
+	VFIO_ASSERT_NOT_NULL(env);
+
+	for (tok = strtok_r(env, " \t\n", &saveptr); tok;
+	     tok = strtok_r(NULL, " \t\n", &saveptr)) {
+		VFIO_ASSERT_TRUE(is_bdf(tok), "Invalid BDF: %s\n", tok);
+		if (count == cap) {
+			cap = cap ? cap * 2 : 4;
+			bdfs = realloc(bdfs, cap * sizeof(*bdfs));
+			VFIO_ASSERT_NOT_NULL(bdfs);
+		}
+		bdfs[count++] = tok;
+	}
+
+	if (!count) {
+		free(env);
+		return NULL;
+	}
+
+	*nr_bdfs = count;
+	return bdfs;
 }
 
 char **vfio_selftests_get_bdfs(int *argc, char *argv[], int *nr_bdfs)
 {
-	static char *env_bdf;
 	char **bdfs;
 
 	bdfs = get_bdfs_cmdline(argc, argv, nr_bdfs);
 	if (bdfs)
 		return bdfs;
 
-	env_bdf = get_bdf_env();
-	if (env_bdf) {
-		*nr_bdfs = 1;
-		return &env_bdf;
-	}
+	bdfs = get_bdfs_env(nr_bdfs);
+	if (bdfs)
+		return bdfs;
 
 	fprintf(stderr, "Unable to determine which device(s) to use, skipping test.\n");
 	fprintf(stderr, "\n");
-	fprintf(stderr, "To pass the device address via environment variable:\n");
+	fprintf(stderr, "To pass the device address(es) via environment variable:\n");
 	fprintf(stderr, "\n");
-	fprintf(stderr, "    export VFIO_SELFTESTS_BDF=\"segment:bus:device.function\"\n");
+	fprintf(stderr, "    export VFIO_SELFTESTS_BDF=\"segment:bus:device.function ...\"\n");
 	fprintf(stderr, "    %s [options]\n", argv[0]);
 	fprintf(stderr, "\n");
 	fprintf(stderr, "To pass the device address(es) via argv:\n");
-- 
2.56.0.567.gdb80ae8cd5-goog