Implement generating an inode table for NFS export

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

9 files changed, 77 insertions, 3 deletions

diff --git a/doc/gensquashfs.1 b/doc/gensquashfs.1
index c52ce70..a880453 100644
--- a/doc/gensquashfs.1
+++ b/doc/gensquashfs.1
@@ -61,6 +61,9 @@ mtime=<value>;0
 If built with SELinux support, use the given SELinux label file to add context
 labels to the elements packed into the SquashFS image.
 .TP
+\fB\-\-exportable\fR, \fB\-e\fR
+Generate an export table for NFS support.
+.TP
 \fB\-\-force\fR, \fB\-f\fR
 Overwrite the output file if it exists.
 .TP
diff --git a/doc/tar2sqfs.1 b/doc/tar2sqfs.1
index 3279794..8c7d20d 100644
--- a/doc/tar2sqfs.1
+++ b/doc/tar2sqfs.1
@@ -58,6 +58,9 @@ extended attributes and skip the ones that cannot be encoded in SquashFS.
 \fB\-\-no\-skip\fR, \fB\-s\fR
 Abort if a tar record cannot be read instead of skipping it.
 .TP
+\fB\-\-exportable\fR, \fB\-e\fR
+Generate an export table for NFS support.
+.TP
 \fB\-\-force\fR, \fB\-f\fR
 Overwrite the output file if it exists.
 .TP
diff --git a/include/highlevel.h b/include/highlevel.h
index 4bc3b7a..12884a0 100644
--- a/include/highlevel.h
+++ b/include/highlevel.h
@@ -75,4 +75,12 @@ int deserialize_fstree(fstree_t *out, sqfs_super_t *super, compressor_t *cmp,
 int write_xattr(int outfd, fstree_t *fs, sqfs_super_t *super,
 		compressor_t *cmp);
 
+/*
+  Generate an NFS export table.
+
+  Returns 0 on success. Prints error messages to stderr on failure.
+ */
+int write_export_table(int outfd, fstree_t *fs, sqfs_super_t *super,
+		       compressor_t *cmp);
+
 #endif /* HIGHLEVEL_H */
diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index 7e6ca82..ab2030c 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -35,6 +35,7 @@ libsquashfs_a_SOURCES += lib/sqfs/deserialize_fstree.c
 libsquashfs_a_SOURCES += lib/sqfs/data_writer.c lib/sqfs/write_xattr.c
 libsquashfs_a_SOURCES += include/data_writer.h include/frag_reader.h
 libsquashfs_a_SOURCES += include/data_reader.h lib/sqfs/data_reader.c
+libsquashfs_a_SOURCES += lib/sqfs/write_export_table.c
 
 libutil_a_SOURCES = lib/util/canonicalize_name.c lib/util/write_data.c
 libutil_a_SOURCES += lib/util/read_data.c include/util.h
diff --git a/lib/sqfs/write_export_table.c b/lib/sqfs/write_export_table.c
new file mode 100644
index 0000000..eee4e01
--- /dev/null
+++ b/lib/sqfs/write_export_table.c
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "highlevel.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int write_export_table(int outfd, fstree_t *fs, sqfs_super_t *super,
+		       compressor_t *cmp)
+{
+	uint64_t *table, start;
+	size_t i;
+	int ret;
+
+	table = malloc(sizeof(uint64_t) * fs->inode_tbl_size);
+
+	if (table == NULL) {
+		perror("Allocating NFS export table");
+		return -1;
+	}
+
+	for (i = 0; i < fs->inode_tbl_size; ++i) {
+		if (fs->inode_table[i] == NULL) {
+			table[i] = 0xFFFFFFFFFFFFFFFF;
+		} else {
+			table[i] = htole64(fs->inode_table[i]->inode_ref);
+		}
+	}
+
+	ret = sqfs_write_table(outfd, super, table, sizeof(table[0]),
+			       fs->inode_tbl_size, &start, cmp);
+
+	super->export_table_start = start;
+	super->flags |= SQFS_FLAG_EXPORTABLE;
+	free(table);
+	return ret;
+}
diff --git a/mkfs/mkfs.c b/mkfs/mkfs.c
index f1c1f1b..91cb9bd 100644
--- a/mkfs/mkfs.c
+++ b/mkfs/mkfs.c
@@ -185,6 +185,11 @@ int main(int argc, char **argv)
 	if (data_writer_write_fragment_table(data))
 		goto out_data;
 
+	if (opt.exportable) {
+		if (write_export_table(outfd, &fs, &super, cmp))
+			goto out_data;
+	}
+
 	if (id_table_write(&idtbl, outfd, &super, cmp))
 		goto out_data;
 
diff --git a/mkfs/mkfs.h b/mkfs/mkfs.h
index 4031c74..70a2ed6 100644
--- a/mkfs/mkfs.h
+++ b/mkfs/mkfs.h
@@ -29,6 +29,7 @@ typedef struct {
 	int outmode;
 	int blksz;
 	int devblksz;
+	bool exportable;
 	bool quiet;
 	const char *infile;
 	const char *packdir;
diff --git a/mkfs/options.c b/mkfs/options.c
index 2dab6b8..fe2bc69 100644
--- a/mkfs/options.c
+++ b/mkfs/options.c
@@ -9,6 +9,7 @@ static struct option long_opts[] = {
 	{ "comp-extra", required_argument, NULL, 'X' },
 	{ "pack-file", required_argument, NULL, 'F' },
 	{ "pack-dir", required_argument, NULL, 'D' },
+	{ "exportable", no_argument, NULL, 'e' },
 	{ "force", no_argument, NULL, 'f' },
 	{ "quiet", no_argument, NULL, 'q' },
 #ifdef WITH_SELINUX
@@ -19,9 +20,9 @@ static struct option long_opts[] = {
 };
 
 #ifdef WITH_SELINUX
-static const char *short_opts = "s:F:D:X:c:b:B:d:fqhV";
+static const char *short_opts = "s:F:D:X:c:b:B:d:efqhV";
 #else
-static const char *short_opts = "F:D:X:c:b:B:d:fqhV";
+static const char *short_opts = "F:D:X:c:b:B:d:efqhV";
 #endif
 
 extern char *__progname;
@@ -66,6 +67,7 @@ static const char *help_string =
 "  --selinux, -s <file>        Specify an SELinux label file to get context\n"
 "                              attributes from.\n"
 #endif
+"  --exportable, -e            Generate an export table for NFS support.\n"
 "  --force, -f                 Overwrite the output file if it exists.\n"
 "  --quiet, -q                 Do not print out progress reports.\n"
 "  --help, -h                  Print help text and exit.\n"
@@ -123,6 +125,7 @@ void process_command_line(options_t *opt, int argc, char **argv)
 	opt->compressor = compressor_get_default();
 	opt->blksz = SQFS_DEFAULT_BLOCK_SIZE;
 	opt->devblksz = SQFS_DEVBLK_SIZE;
+	opt->exportable = false;
 	opt->quiet = false;
 	opt->infile = NULL;
 	opt->packdir = NULL;
@@ -166,6 +169,9 @@ void process_command_line(options_t *opt, int argc, char **argv)
 		case 'd':
 			opt->fs_defaults = optarg;
 			break;
+		case 'e':
+			opt->exportable = true;
+			break;
 		case 'f':
 			opt->outmode = O_WRONLY | O_CREAT | O_TRUNC;
 			break;
diff --git a/tar/tar2sqfs.c b/tar/tar2sqfs.c
index 3417fd0..8394b7f 100644
--- a/tar/tar2sqfs.c
+++ b/tar/tar2sqfs.c
@@ -26,13 +26,14 @@ static struct option long_opts[] = {
 	{ "comp-extra", required_argument, NULL, 'X' },
 	{ "no-skip", no_argument, NULL, 's' },
 	{ "no-xattr", no_argument, NULL, 'x' },
+	{ "exportable", no_argument, NULL, 'e' },
 	{ "force", no_argument, NULL, 'f' },
 	{ "quiet", no_argument, NULL, 'q' },
 	{ "help", no_argument, NULL, 'h' },
 	{ "version", no_argument, NULL, 'V' },
 };
 
-static const char *short_opts = "c:b:B:d:X:sxfqhV";
+static const char *short_opts = "c:b:B:d:X:sxefqhV";
 
 static const char *usagestr =
 "Usage: tar2sqfs [OPTIONS...] <sqfsfile>\n"
@@ -63,6 +64,7 @@ static const char *usagestr =
 "  --no-skip, -s               Abort if a tar record cannot be read instead\n"
 "                              of skipping it.\n"
 "  --no-xattr, -x              Do not copy extended attributes from archive.\n"
+"  --exportable, -e            Generate an export table for NFS support.\n"
 "  --force, -f                 Overwrite the output file if it exists.\n"
 "  --quiet, -q                 Do not print out progress reports.\n"
 "  --help, -h                  Print help text and exit.\n"
@@ -85,6 +87,7 @@ static char *comp_extra = NULL;
 static char *fs_defaults = NULL;
 static bool dont_skip = false;
 static bool no_xattr = false;
+static bool exportable = false;
 
 static void process_args(int argc, char **argv)
 {
@@ -137,6 +140,9 @@ static void process_args(int argc, char **argv)
 		case 's':
 			dont_skip = true;
 			break;
+		case 'e':
+			exportable = true;
+			break;
 		case 'f':
 			outmode = O_WRONLY | O_CREAT | O_TRUNC;
 			break;
@@ -388,6 +394,11 @@ int main(int argc, char **argv)
 	if (data_writer_write_fragment_table(data))
 		goto out;
 
+	if (exportable) {
+		if (write_export_table(outfd, &fs, &super, cmp))
+			goto out;
+	}
+
 	if (id_table_write(&idtbl, outfd, &super, cmp))
 		goto out;