[Minios-devel] [UNIKRAFT PATCH v2 6/6] lib/ukboot: Root filesystem as library parameter

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

Enables support for setting fsname, device, flags, and mount data
for the root filesystem. These options can configured through the menu
configuration. In case libukparam is enabled, the default values can
be overwritten with the kernel command line; for example:
  init.root_fsname="ramfs"

Signed-off-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
---
 lib/ukboot/Config.uk   | 22 ++++++++++++++++++++--
 lib/ukboot/Makefile.uk |  3 +++
 lib/ukboot/boot.c      | 36 ++++++++++++++++++++++--------------
 3 files changed, 45 insertions(+), 16 deletions(-)

diff --git a/lib/ukboot/Config.uk b/lib/ukboot/Config.uk
index 8420aae9..d9d57715 100644
--- a/lib/ukboot/Config.uk
+++ b/lib/ukboot/Config.uk
@@ -22,11 +22,29 @@ if LIBUKBOOT
        default y
        select LIBUKALLOCBBUDDY
 
-       config LIBUKBOOT_VFSROOT
-       bool "Mount ramfs to /"
+       menuconfig LIBUKBOOT_VFSROOT
+       bool "Mount a root filesysytem (/)"
        default n
        select LIBRAMFS
 
+       if LIBUKBOOT_VFSROOT
+               config LIBUKBOOT_VFSROOT_FSNAME
+               string "Default root filesystem"
+               default "ramfs"
+
+               config LIBUKBOOT_VFSROOT_DEV
+               string "Default root device"
+               default ""
+
+               config LIBUKBOOT_VFSROOT_FLAGS
+               hex "Default root mount flags"
+               default 0x0
+
+               config LIBUKBOOT_VFSROOT_DATA
+               string "Default root mount data"
+               default ""
+       endif
+
        config LIBUKBOOT_DEVFS
        bool "Mount devfs to /dev"
        default n
diff --git a/lib/ukboot/Makefile.uk b/lib/ukboot/Makefile.uk
index ea052019..fa5c1aea 100644
--- a/lib/ukboot/Makefile.uk
+++ b/lib/ukboot/Makefile.uk
@@ -1,5 +1,8 @@
 $(eval $(call addlib_s,libukboot,$(CONFIG_LIBUKBOOT)))
 
+# Register to uklibparam, sets "ini" as paramprefix
+$(eval $(call addlib_paramprefix,libukboot,init))
+
 CINCLUDES-$(CONFIG_LIBUKBOOT)          += -I$(LIBUKBOOT_BASE)/include
 CXXINCLUDES-$(CONFIG_LIBUKBOOT)        += -I$(LIBUKBOOT_BASE)/include
 
diff --git a/lib/ukboot/boot.c b/lib/ukboot/boot.c
index 5e2cb757..4e34ef76 100644
--- a/lib/ukboot/boot.c
+++ b/lib/ukboot/boot.c
@@ -60,14 +60,23 @@
 #if CONFIG_LIBUKBUS
 #include <uk/bus.h>
 #endif /* CONFIG_LIBUKBUS */
-#ifdef CONFIG_LIBUKLIBPARAM
 #include <uk/libparam.h>
-#endif /* CONFIG_LIBUKLIBPARAM */
 #ifdef CONFIG_LIBUKBOOT_VFSROOT
 #include <sys/stat.h>
 #include <sys/mount.h>
 #endif /* CONFIG_LIBUKBOOT_VFSROOT */
 
+#ifdef CONFIG_LIBUKBOOT_VFSROOT
+static char *root_fsname = CONFIG_LIBUKBOOT_VFSROOT_FSNAME;
+static char *root_dev    = CONFIG_LIBUKBOOT_VFSROOT_DEV;
+static char *root_data   = CONFIG_LIBUKBOOT_VFSROOT_DATA;
+static __u64 root_flags  = (__u64) CONFIG_LIBUKBOOT_VFSROOT_FLAGS;
+
+UK_LIB_PARAM_STR(root_fsname);
+UK_LIB_PARAM_STR(root_dev);
+UK_LIB_PARAM(root_flags,  __u64);
+UK_LIB_PARAM_STR(root_data);
+#endif
 
 int main(int argc, char *argv[]) __weak;
 #ifdef CONFIG_LIBLWIP
@@ -98,25 +107,24 @@ static void main_thread_func(void *arg)
         * VFS initialization
         */
 #ifdef CONFIG_LIBUKBOOT_VFSROOT
-       /*
-        * TODO: Provide a boot parameter option to specify a custom
-        * root mount (e.g., ramfs, initrd, 9pfs).
-        */
-       uk_pr_info("Mount root...\n");
-       ret = mount("", "/", "ramfs", 0, NULL);
+       uk_pr_info("Mount root (%s)...\n", root_fsname);
+       ret = mount(root_dev, "/", root_fsname, root_flags, root_data);
        if (ret != 0)
-               UK_CRASH("Failed to mount ramfs to /\n");
+               UK_CRASH("Failed to mount /\n");
 
        /*
-        * TODO: We could place here code that extracts an archive
-        * found as initrd to '/'
+        * TODO: Alternatively we could extract an archive found
+        * as initrd to a ramfs '/' if we have got fsname 'initrd'
         */
 
 #ifdef CONFIG_LIBUKBOOT_DEVFS
        uk_pr_info("Mount '/dev'...\n");
-       ret =  mkdir("/dev", S_IRWXU);
-       if (ret != 0)
-               UK_CRASH("Failed to create directory '/dev'\n");
+
+       /*
+        * Try to create the mount point.
+        * We are ignoring errors because it could exist already.
+        */
+       mkdir("/dev", S_IRWXU);
 
        ret = mount("", "/dev", "devfs", 0, NULL);
        if (ret != 0)
-- 
2.20.1


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