From a84d1c5d58fa4a0c9e087357eec009803ea06ef2 Mon Sep 17 00:00:00 2001
From: Ingo Franzki <ifranzki@linux.ibm.com>
Date: Thu, 13 Jun 2019 10:28:11 +0200
Subject: [PATCH] zkey: Add utility function to get the serial number of a
 crypto card
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With recent changes in the zcrypt device driver, the serial number of
a crypto card can be obtained by reading the sysfs attribute 'serialnr'
of a crypto card device of type CCA-Coprocessor. The sysfs attribute
can be found under '/sys/devices/ap/cardnn/', where nn specifies the
card number in hex.

Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
---
 zkey/utils.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 zkey/utils.h |  2 ++
 2 files changed, 54 insertions(+)

diff --git a/zkey/utils.c b/zkey/utils.c
index ac6dfbef..1d2ee7cb 100644
--- a/zkey/utils.c
+++ b/zkey/utils.c
@@ -22,6 +22,11 @@
 
 #include "utils.h"
 
+#define pr_verbose(verbose, fmt...)	do {				\
+						if (verbose)		\
+							warnx(fmt);	\
+					} while (0)
+
 /**
  * Checks if the specified card is of type CCA and is online
  *
@@ -107,3 +112,50 @@ out:
 	return rc;
 }
 
+/**
+ * Gets the 8 character ASCII serial number string of an card from the sysfs.
+ *
+ * @param[in] card      card number
+ * @param[out] serialnr Result buffer
+ * @param[in] verbose   if true, verbose messages are printed
+ *
+ * @returns 0 if the serial number was returned. -ENODEV if the APQN is not
+ *          available, or is not a CCA card. -ENOTSUP if the serialnr sysfs
+ *          attribute is not available, because the zcrypt kernel module is
+ *          on an older level.
+ */
+int sysfs_get_serialnr(int card, char serialnr[9], bool verbose)
+{
+	char *dev_path;
+	int rc = 0;
+
+	if (serialnr == NULL)
+		return -EINVAL;
+
+	if (sysfs_is_card_online(card) != 1)
+		return -ENODEV;
+
+	dev_path = util_path_sysfs("bus/ap/devices/card%02x", card);
+	if (!util_path_is_dir(dev_path)) {
+		rc = -ENODEV;
+		goto out;
+	}
+	if (util_file_read_line(serialnr, 9, "%s/serialnr", dev_path) != 0) {
+		rc = -ENOTSUP;
+		goto out;
+	}
+
+	if (strlen(serialnr) == 0) {
+		rc = -ENODEV;
+		goto out;
+	}
+
+	pr_verbose(verbose, "Serial number of %02x: %s", card, serialnr);
+out:
+	if (rc != 0)
+		pr_verbose(verbose, "Failed to get serial number for "
+			   "%02x: %s", card, strerror(-rc));
+
+	free(dev_path);
+	return rc;
+}
diff --git a/zkey/utils.h b/zkey/utils.h
index fdbf3c05..0659fd64 100644
--- a/zkey/utils.h
+++ b/zkey/utils.h
@@ -18,4 +18,6 @@ int sysfs_is_card_online(int card);
 
 int sysfs_is_apqn_online(int card, int domain);
 
+int sysfs_get_serialnr(int card, char serialnr[9], bool verbose);
+
 #endif