zipl: Implement zipl helper script for NGDump

The purpose of the new zipl helper script is to build a dumper initramfs
for NGDump stand-alone dump. zipl executes the helper script when
preparing a NVMe dump partition for stand-alone dump.

The zipl helper script expects a single parameter - a path to the dump
partition to store a dump on. The helper script terminates with 0 on
success and a positive value otherwise.

The zipl helper script performs the following steps:
- It builds an initramfs image suitable for dumping. To perform this step,
  the script employs the dracut tool on Fedora/RHEL/SLES and
  the initramfs-tools on Ubuntu/Debian.
- It outputs the path to the newly built initramfs image and the currently
  active kernel bzImage on the standard output.
- It prints the kernel command-line to be used by the dumper on
  the standard output.

On success, zipl expects the helper script to return at least three lines
containing:
- initrd=<path to an initramfs image>
- kernel=<path to a kernel bzImage>
- cmdline=<kernel command-line parameters>

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Tested-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zipl/dracut/Makefile

@@ -15,6 +15,8 @@ NGDUMPDIR := 99ngdump
 #
 ifeq ($(HAVE_DRACUT),1)
 install:
+	$(INSTALL) -m 755 zipl_helper.prepare-ngdump \
+		$(DESTDIR)$(TOOLS_LIBDIR)
 	$(INSTALL) -m 755 -d $(DESTDIR)$(MODULESDIR)
 	$(INSTALL) -m 755 -d $(DESTDIR)$(MODULESDIR)/$(NGDUMPDIR)
 	$(INSTALL) -m 755 $(NGDUMPDIR)/module-setup.sh \

zipl/dracut/zipl_helper.prepare-ngdump

@@ -0,0 +1,93 @@
+#!/bin/bash
+#
+# Copyright IBM Corp. 2021
+#
+# s390-tools is free software; you can redistribute it and/or modify
+# it under the terms of the MIT license. See LICENSE for details.
+#
+
+set -u
+
+DRACUT_OMIT_MODULES=(
+	nfs network network-manager
+	dbus dbus-broker dbus-daemon plymouth
+	znet dash resume ifcfg earlykdump
+	kdumpcore i18n lvm mdraid memstrack
+	systemd-timedated systemd-timesyncd
+	systemd-networkd systemd-network-manager systemd-coredump)
+
+[ $# -gt 0 ] || { echo "Usage: $0 <dump partition device>" >&2; exit 1; }
+
+#
+# Retrieve partition UUID
+#
+# We use PARTUUID because zipl re-formats the given partition after
+# calling us, therefore, a UUID will change.
+#
+device=$(readlink -f $1)
+disk_path=/dev/disk/by-partuuid/$(blkid -o value -s PARTUUID "$device")
+
+[ -e "$disk_path" ] || { echo "Couldn't find disk by PARTUUID." >&2; exit 1; }
+
+function get_kernel_version()
+{
+	local version=$(uname -r)
+
+	echo $version
+}
+
+function get_kernel_image()
+{
+	local version=$1
+
+	if [ -e "/boot/image-$version" ]; then
+		# SLES kernel image
+		echo "/boot/image-$version"
+	else
+		# Fedora/RHEL kernel image
+		echo "/boot/vmlinuz-$version"
+	fi
+}
+
+#
+# dracut is the standard tool for building initramfs images
+# on Fedora, RHEL, and SLES.
+#
+function create_initrd()
+{
+	local disk=$1
+	local kver=$2
+	local initrd=$3
+	local omit_modules=$(echo ${DRACUT_OMIT_MODULES[@]})
+
+	command -v dracut >/dev/null ||
+		{ echo "Please install dracut." >&2; return 1; }
+
+	dracut -v --hostonly --no-hostonly-cmdline --hostonly-i18n \
+	       -o "$omit_modules" --add ngdump \
+	       --mount "$disk /ngdump ext4 defaults" \
+	       --kver "$kver" -f "$initrd" 2>&1
+}
+
+kernel_version=$(get_kernel_version)
+kernel=$(get_kernel_image "$kernel_version")
+[ -e "$kernel" ] || { echo "Couldn't find kernel image." >&2; exit 1; }
+
+initrd=$(mktemp)
+create_initrd "$disk_path" "$kernel_version" "$initrd"
+[ $? -eq 0 ] || { echo "Failed to create initramfs image" >&2; exit 1; }
+
+#
+# zipl expects this script to output three variables to stdout:
+#  * kernel: path to bzImage file of Linux kernel
+#  * initrd: path to dumper initramfs image
+#  * cmdline: command-line for dumper's kernel
+#
+# The output order is irrelevant.
+#
+
+echo "kernel=$kernel"
+echo "initrd=$initrd"
+echo "cmdline=reset_devices cgroup_disable=memory nokaslr numa=off irqpoll nr_cpus=1"
+
+exit 0

zipl/include/job.h

@@ -135,5 +135,6 @@ int job_get(int argc, char* argv[], struct job_data** data);
 void job_free(struct job_data* job);
 int type_from_target(char *target, disk_type_t *type);
 int check_job_dump_images(struct job_dump_data* dump, char* name);
+int check_job_images_ngdump(struct job_dump_data* dump, char* name);
 
 #endif /* not JOB_H */

zipl/initramfs-tools/Makefile

@@ -16,6 +16,8 @@ INITPREMOUNTDIR := $(INITRAMFSTOOLSDIR)/scripts/init-premount
 #
 ifeq ($(HAVE_INITRAMFS),1)
 install:
+	$(INSTALL) -m 755 zipl_helper.prepare-ngdump \
+		$(DESTDIR)$(TOOLS_LIBDIR)
 	$(INSTALL) -m 755 -d $(DESTDIR)$(HOOKSDIR)
 	$(INSTALL) -m 755 -d $(DESTDIR)$(INITPREMOUNTDIR)
 	$(INSTALL) -m 755 hooks/ngdump $(DESTDIR)$(HOOKSDIR)/

zipl/initramfs-tools/zipl_helper.prepare-ngdump

@@ -0,0 +1,73 @@
+#!/bin/bash
+#
+# Copyright IBM Corp. 2021
+#
+# s390-tools is free software; you can redistribute it and/or modify
+# it under the terms of the MIT license. See LICENSE for details.
+#
+
+[ $# -gt 0 ] || { echo "Usage: $0 <dump partition device>" >&2; exit 1; }
+
+#
+# Retrieve partition UUID
+#
+# We use PARTUUID because zipl re-formats the given partition after
+# calling us, therefore, a UUID will change.
+#
+device=$(readlink -f $1)
+disk_path=/dev/disk/by-partuuid/$(blkid -o value -s PARTUUID "$device")
+
+[ -e "$disk_path" ] || { echo "Couldn't find disk by PARTUUID." >&2; exit 1; }
+
+function get_kernel_version()
+{
+	local version=$(uname -r)
+
+	echo $version
+}
+
+function get_kernel_image()
+{
+	local version=$1
+
+	echo "/boot/vmlinuz-$version"
+}
+
+#
+# initramfs-tools is the standard tool for building initramfs images
+# on Ubuntu and Debian.
+#
+function create_initrd()
+{
+	local disk=$1
+	local kver=$2
+	local initrd=$3
+
+	command -v mkinitramfs >/dev/null ||
+		{ echo "Please install mkinitramfs." >&2; return 1; }
+
+	NGDUMP=y NGDUMP_DEVICE="$disk" mkinitramfs -o "$initrd" "$kver" 2>&1
+}
+
+kernel_version=$(get_kernel_version)
+kernel=$(get_kernel_image "$kernel_version")
+[ -e "$kernel" ] || { echo "Couldn't find kernel image." >&2; exit 1; }
+
+initrd=$(mktemp)
+create_initrd "$disk_path" "$kernel_version" "$initrd"
+[ $? -eq 0 ] || { echo "Failed to create initramfs image" >&2; exit 1; }
+
+#
+# zipl expects this script to output three variables to stdout:
+#  * kernel: path to bzImage file of Linux kernel
+#  * initrd: path to dumper initramfs image
+#  * cmdline: command-line for dumper's kernel
+#
+# The output order is irrelevant.
+#
+
+echo "kernel=$kernel"
+echo "initrd=$initrd"
+echo "cmdline=reset_devices cgroup_disable=memory nokaslr numa=off irqpoll nr_cpus=1"
+
+exit 0

zipl/src/job.c

@@ -896,6 +896,92 @@ check_job_dump_images(struct job_dump_data* dump, char* name)
 }
 
 
+int
+check_job_images_ngdump(struct job_dump_data* dump, char *name)
+{
+	const char *helper = TOOLS_LIBDIR "/zipl_helper.prepare-ngdump";
+	char *ppn_cmd = NULL;
+	char *line = NULL;
+	FILE *fp;
+	int rc;
+
+	misc_asprintf(&ppn_cmd, "%s %s", helper, dump->device);
+	printf("Run %s\n", ppn_cmd);
+
+	fp = popen(ppn_cmd, "r");
+	if (fp == NULL) {
+		error_reason("Failed to run popen(%s,\"r\",)");
+		free(ppn_cmd);
+		return -1;
+	}
+	free(ppn_cmd);
+
+	while (fscanf(fp, "%m[^\n]\n", &line) != EOF) {
+		char *param = NULL;
+		char *value = NULL;
+
+		int n = sscanf(line, "%m[^=]=%m[^\n]\n", &param, &value);
+
+		if (n != 2) {
+			if (verbose)
+				printf("%s\n", line);
+			free(line);
+			free(param);
+			free(value);
+			continue;
+		}
+
+		if (strcmp(param, "kernel") == 0) {
+			dump->common.image = value;
+			value = NULL;
+		} else if (strcmp(param, "initrd") == 0) {
+			dump->common.ramdisk = value;
+			value = NULL;
+		} else if (strcmp(param, "cmdline") == 0) {
+			dump->common.parmline = value;
+			value = NULL;
+		} else {
+			printf("%s\n", line);
+		}
+
+		free(line);
+		free(param);
+		free(value);
+	}
+
+	switch (pclose(fp)) {
+	case 0:
+		/* success */
+		break;
+	case -1:
+		error_reason("Failed to run pclose");
+		return -1;
+	default:
+		error_reason("Script could not determine dump parameters");
+		return -1;
+	}
+
+	rc = misc_check_readable_file(dump->common.image);
+	if (rc) {
+		error_text("Need external file '%s' for dump",
+			   dump->common.image);
+		return rc;
+	}
+	dump->common.image_addr = IMAGE_LOAD_ADDRESS;
+
+	rc = misc_check_readable_file(dump->common.ramdisk);
+	if (rc) {
+		error_text("Need external file '%s' for dump",
+			   dump->common.ramdisk);
+		return rc;
+	}
+	dump->common.ramdisk_addr = UNSPECIFIED_ADDRESS;
+
+	dump->common.parm_addr = UNSPECIFIED_ADDRESS;
+	return finalize_common_address_data(&dump->common, name);
+}
+
+
 static int
 check_job_menu_data(struct job_menu_data *menu, struct job_envblk_data *envblk)
 {