5 files changed, 291 insertions, 1 deletions

diff --git a/stand/kboot/Makefile b/stand/kboot/Makefile
index 518e945a596e..c8bd313d1d1d 100644
--- a/stand/kboot/Makefile
+++ b/stand/kboot/Makefile
@@ -25,6 +25,7 @@ SRCS=	\
 		host_syscalls.c \
 		hostcons.c \
 		hostdisk.c \
+		hostfs.c \
 		init.c \
 		kbootfdt.c \
 		main.c \
diff --git a/stand/kboot/conf.c b/stand/kboot/conf.c
index b840d008a347..26788342c4b9 100644
--- a/stand/kboot/conf.c
+++ b/stand/kboot/conf.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #endif
 
 extern struct devsw hostdisk;
+extern struct devsw host_dev;
 
 /*
  * We could use linker sets for some or all of these, but
@@ -53,9 +54,12 @@ struct devsw *devsw[] = {
 #if defined(LOADER_NET_SUPPORT)
     &netdev,
 #endif
+    &host_dev,
     NULL
 };
 
+extern struct fs_ops hostfs_fsops;
+
 struct fs_ops *file_system[] = {
 #if defined(LOADER_UFS_SUPPORT)
     &ufs_fsops,
@@ -79,6 +83,7 @@ struct fs_ops *file_system[] = {
     &bzipfs_fsops,
 #endif
     &dosfs_fsops,
+    &hostfs_fsops,
     NULL
 };
 
diff --git a/stand/kboot/hostfs.c b/stand/kboot/hostfs.c
new file mode 100644
index 000000000000..08f532999abe
--- /dev/null
+++ b/stand/kboot/hostfs.c
@@ -0,0 +1,280 @@
+/*-
+ * Copyright (c) 2022 Netflix, Inc
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <sys/types.h>
+#include "stand.h"
+#include "host_syscall.h"
+#include "kboot.h"
+
+#define HOST_PATH_MAX	1025
+
+extern struct devsw host_dev;
+
+const char *hostfs_root = "/";
+
+enum FTYPE {
+	regular,
+	dir,
+};
+
+typedef struct _hostfs_file {
+	enum FTYPE	hf_type;
+	int		hf_fd;
+	/* The following are only used for FTYPE == dir */
+	char		hf_dents[2048];
+	char		*hf_curdent;
+	int		hf_dentlen;	/* Valid part of hf_dents */
+} hostfs_file;
+
+static hostfs_file *
+hostfs_alloc(void)
+{
+	hostfs_file *hf;
+
+	hf = malloc(sizeof(*hf));
+	if (hf != NULL)
+		memset(hf, 0, sizeof(*hf));
+	return (hf);
+}
+
+static void
+hostfs_free(hostfs_file *hf)
+{
+	free(hf);
+}
+
+static int
+hostfs_open(const char *fn, struct open_file *f)
+{
+	hostfs_file *hf;
+	struct host_kstat ksb;
+	char path[HOST_PATH_MAX];
+
+	if (f->f_dev != &host_dev) {
+		return (EINVAL);
+	}
+
+	/*
+	 * Normally, we root everything at hostfs_root. However, there are two
+	 * exceptions that make it easier to write code. First is /sys and /proc
+	 * are special Linux filesystems, so we pass those paths
+	 * through. Second, if the path starts with //, then we strip off the
+	 * first / and pass it through (in a weird way, this is actually in
+	 * POSIX: hosts are allowed to do specail things with paths that start
+	 * with two //, but one or three or more are required to be treated as
+	 * one).
+	 */
+	if (strncmp("/sys/", fn, 5) == 0 || strncmp("/proc/", fn, 6) == 0)
+		strlcpy(path, fn, sizeof(path));
+	else if (fn[0] == '/' && fn[1] == '/' && fn[2] != '/')
+		strlcpy(path, fn + 1, sizeof(path));
+	else
+		snprintf(path, sizeof(path), "%s/%s", hostfs_root, fn);
+	hf = hostfs_alloc();
+	hf->hf_fd = host_open(path, HOST_O_RDONLY, 0);
+	if (hf->hf_fd < 0) {
+		hostfs_free(hf);
+		return (EINVAL);
+	}
+
+	if (host_fstat(hf->hf_fd, &ksb) < 0) {
+		hostfs_free(hf);
+		return (EINVAL);
+	}
+	if (S_ISDIR(hf->hf_fd)) {
+		hf->hf_type = dir;
+	} else {
+		hf->hf_type = regular;
+	}
+	f->f_fsdata = hf;
+	return (0);
+}
+
+static int
+hostfs_close(struct open_file *f)
+{
+	hostfs_file *hf = f->f_fsdata;
+
+	host_close(hf->hf_fd);
+	hostfs_free(hf);
+	f->f_fsdata = NULL;
+
+	return (0);
+}
+
+static int
+hostfs_read(struct open_file *f, void *start, size_t size, size_t *resid)
+{
+	hostfs_file *hf = f->f_fsdata;
+	ssize_t sz;
+
+	sz = host_read(hf->hf_fd, start, size);
+	if (sz < 0) {
+		return (EINVAL);
+	}
+	*resid = size - sz;
+
+	return (0);
+}
+
+static off_t
+hostfs_seek(struct open_file *f, off_t offset, int whence)
+{
+	hostfs_file *hf = f->f_fsdata;
+	uint32_t offl, offh;
+	int err;
+	uint64_t res;
+
+	/*
+	 * Assumes Linux host with 'reduced' system call wrappers. Also assume
+	 * host and libstand have same whence encoding (safe since it all comes
+	 * from V7 later ISO-C). Also assumes we have to support powerpc still,
+	 * it's interface is weird for legacy reasons....
+	 */
+	offl = offset & 0xffffffff;
+	offh = (offset >> 32) & 0xffffffff;
+	err = host_llseek(hf->hf_fd, offh, offl, &res, whence);
+	if (err < 0)
+		return (err);
+	return (res);
+}
+
+static int
+hostfs_stat(struct open_file *f, struct stat *sb)
+{
+	struct host_kstat ksb;
+	hostfs_file *hf = f->f_fsdata;
+
+	if (host_fstat(hf->hf_fd, &ksb) < 0)
+		return (EINVAL);
+	/*
+	 * Translate Linux stat info to lib stand's notion (which uses FreeBSD's
+	 * stat structure, missing fields are zero and commented below).
+	 */
+	memset(sb, 0, sizeof(*sb));
+	sb->st_dev		= ksb.st_dev;
+	sb->st_ino		= ksb.st_ino;
+	sb->st_nlink		= ksb.st_nlink;
+	sb->st_mode		= ksb.st_mode;
+	sb->st_uid		= ksb.st_uid;
+	sb->st_gid		= ksb.st_gid;
+	sb->st_rdev		= ksb.st_rdev;
+	/* No st_?time_ext on i386 */
+	sb->st_atim.tv_sec	= ksb.st_atime_sec;
+	sb->st_atim.tv_nsec	= ksb.st_atime_nsec;
+	sb->st_mtim.tv_sec	= ksb.st_mtime_sec;
+	sb->st_mtim.tv_nsec	= ksb.st_mtime_nsec;
+	sb->st_ctim.tv_sec	= ksb.st_ctime_sec;
+	sb->st_ctim.tv_nsec	= ksb.st_ctime_nsec;
+	/* No st_birthtim */
+	sb->st_size		= ksb.st_size;
+	sb->st_blocks		= ksb.st_blocks;
+	sb->st_blksize		= ksb.st_blksize;
+	/* no st_flags */
+	/* no st_get */
+
+	return (0);
+}
+
+static int
+hostfs_readdir(struct open_file *f, struct dirent *d)
+{
+	hostfs_file *hf = f->f_fsdata;
+	int dentlen;
+	struct host_dirent64 *dent;
+
+	if (hf->hf_curdent == NULL) {
+		dentlen = host_getdents64(hf->hf_fd, hf->hf_dents, sizeof(hf->hf_dents));
+		if (dentlen <= 0)
+			return (EINVAL);
+		hf->hf_dentlen = dentlen;
+		hf->hf_curdent = hf->hf_dents;
+	}
+	dent = (struct host_dirent64 *)hf->hf_curdent;
+	d->d_fileno = dent->d_ino;
+	d->d_type = dent->d_type;	/* HOST_DT_XXXX == DX_XXXX for all values */
+	strlcpy(d->d_name, dent->d_name, sizeof(d->d_name)); /* d_name is NUL terminated */
+	d->d_namlen = strlen(d->d_name);
+	hf->hf_curdent += dent->d_reclen;
+	if (hf->hf_curdent >= hf->hf_dents + hf->hf_dentlen) {
+		hf->hf_curdent = NULL;
+		hf->hf_dentlen = 0;
+	}
+
+	return (0);
+}
+
+struct fs_ops hostfs_fsops = {
+	.fs_name = "host",
+	.fo_open = hostfs_open,
+	.fo_close = hostfs_close,
+	.fo_read = hostfs_read,
+	.fo_write = null_write,
+	.fo_seek = hostfs_seek,
+	.fo_stat = hostfs_stat,
+	.fo_readdir = hostfs_readdir
+};
+
+/*
+ * Generic "null" host device. This goes hand and hand with the host fs object
+ *
+ * XXXX This and userboot for bhyve both use exactly the same code, modulo some
+ * formatting nits. Make them common. We mostly use it to 'gate' the open of the
+ * filesystem to only this device.
+ */
+
+static int
+host_dev_init(void)
+{
+	return (0);
+}
+
+static int
+host_dev_print(int verbose)
+{
+	char line[80];
+
+	printf("%s devices:", host_dev.dv_name);
+	if (pager_output("\n") != 0)
+		return (1);
+
+	snprintf(line, sizeof(line), "    host%d:   Host filesystem\n", 0);
+	return (pager_output(line));
+}
+
+/*
+ * 'Open' the host device.
+ */
+static int
+host_dev_open(struct open_file *f, ...)
+{
+	return (0);
+}
+
+static int
+host_dev_close(struct open_file *f)
+{
+	return (0);
+}
+
+static int
+host_dev_strategy(void *devdata, int rw, daddr_t dblk, size_t size,
+    char *buf, size_t *rsize)
+{
+	return (ENOSYS);
+}
+
+struct devsw host_dev = {
+	.dv_name = "host",
+	.dv_type = DEVT_NET,
+	.dv_init = host_dev_init,
+	.dv_strategy = host_dev_strategy,
+	.dv_open = host_dev_open,
+	.dv_close = host_dev_close,
+	.dv_ioctl = noioctl,
+	.dv_print = host_dev_print,
+	.dv_cleanup = NULL
+};
diff --git a/stand/kboot/kboot.h b/stand/kboot/kboot.h
index 81bd18faa893..5441c90eaecc 100644
--- a/stand/kboot/kboot.h
+++ b/stand/kboot/kboot.h
@@ -11,6 +11,8 @@
 
 void do_init(void);
 
+extern const char *hostfs_root;
+
 /* Per-platform fdt fixup */
 void fdt_arch_fixups(void *fdtp);
 
diff --git a/stand/kboot/main.c b/stand/kboot/main.c
index 10dd6b05194b..23211ce9df4c 100644
--- a/stand/kboot/main.c
+++ b/stand/kboot/main.c
@@ -120,8 +120,10 @@ main(int argc, const char **argv)
 		bootdev = argv[1];
 	else
 		bootdev = "";
+	if (argc > 2)
+		hostfs_root = argv[2];
 
-	printf("Boot device: %s\n", bootdev);
+	printf("Boot device: %s with hostfs_root %s\n", bootdev, hostfs_root);
 
 	archsw.arch_getdev = kboot_getdev;
 	archsw.arch_copyin = kboot_copyin;