Date:	Sat, 12 Mar 2016 02:14:36 -0500
From:	Theodore Ts'o <tytso@....edu>
To:	darrick.wong@...cle.com
Cc:	Ext4 Developers List <linux-ext4@...r.kernel.org>,
	Theodore Ts'o <tytso@....edu>
Subject: [PATCH] fuse2fs: improve command-line parsing

Use libfuse's command line parsing, which is much more powerful and
flexible than what we had before, and to allow the user to have more
fine-grained control over FUSE's run-time options.

Signed-off-by: Theodore Ts'o <tytso@....edu>
---
 misc/fuse2fs.c | 185 +++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 120 insertions(+), 65 deletions(-)

diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index 1cbdcb7..4412fe3 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -36,6 +36,8 @@
 #include "ext2fs/ext2fs.h"
 #include "ext2fs/ext2_fs.h"
 
+#include "../version.h"
+
 #ifdef ENABLE_NLS
 #include <libintl.h>
 #include <locale.h>
@@ -303,6 +305,10 @@ struct fuse2fs {
 	unsigned long magic;
 	ext2_filsys fs;
 	pthread_mutex_t bfl;
+	char *device;
+	int ro;
+	int debug;
+	int no_default_opts;
 	int panic_on_error;
 	int minixdf;
 	int alloc_all_blocks;
@@ -3624,49 +3630,100 @@ static int get_random_bytes(void *p, size_t sz)
 	return (size_t) r == sz;
 }
 
-static void print_help(const char *progname)
+enum {
+	FUSE2FS_VERSION,
+	FUSE2FS_HELP,
+	FUSE2FS_HELPFULL,
+};
+
+#define FUSE2FS_OPT(t, p, v) { t, offsetof(struct fuse2fs, p), v }
+
+static struct fuse_opt fuse2fs_opts[] = {
+	FUSE2FS_OPT("ro",		ro,			1),
+	FUSE2FS_OPT("errors=panic",	panic_on_error,		1),
+	FUSE2FS_OPT("minixdf",		minixdf,		1),
+	FUSE2FS_OPT("fuse2fs_debug",	debug,			1),
+	FUSE2FS_OPT("no_default_opts",	no_default_opts,	1),
+
+	FUSE_OPT_KEY("-V",             FUSE2FS_VERSION),
+	FUSE_OPT_KEY("--version",      FUSE2FS_VERSION),
+	FUSE_OPT_KEY("-h",             FUSE2FS_HELP),
+	FUSE_OPT_KEY("--help",         FUSE2FS_HELP),
+	FUSE_OPT_KEY("--helpfull",     FUSE2FS_HELPFULL),
+	FUSE_OPT_END
+};
+
+
+static int fuse2fs_opt_proc(void *data, const char *arg,
+			    int key, struct fuse_args *outargs)
 {
-	printf(_("Usage: %s dev mntpt [-o options] [fuse_args]\n"), progname);
+	struct fuse2fs *ff = data;
+
+	switch (key) {
+	case FUSE_OPT_KEY_NONOPT:
+		if (!ff->device) {
+			ff->device = strdup(arg);
+			return 0;
+		}
+		return 1;
+	case FUSE2FS_HELP:
+	case FUSE2FS_HELPFULL:
+		fprintf(stderr,
+	"usage: %s device/image mountpoint [options]\n"
+	"\n"
+	"general options:\n"
+	"    -o opt,[opt...]  mount options\n"
+	"    -h   --help      print help\n"
+	"    -V   --version   print version\n"
+	"\n"
+	"fuse2fs options:\n"
+	"    -o ro                  read-only mount\n"
+	"    -o errors=panic        dump core on error\n"
+	"    -o minixdf             minix-style df\n"
+	"    -o no_default_opts     do not include default fuse options\n"
+	"    -o fuse2fs_debug       enable fuse2fs debugging\n"
+	"\n",
+			outargs->argv[0]);
+		if (key == FUSE2FS_HELPFULL) {
+			fuse_opt_add_arg(outargs, "-ho");
+			fuse_main(outargs->argc, outargs->argv, &fs_ops, NULL);
+		} else {
+			fprintf(stderr, "Try --helpfull to get a list of "
+				"all flags, including the FUSE options.\n");
+		}
+		exit(1);
+
+	case FUSE2FS_VERSION:
+		fprintf(stderr, "fuse2fs %s (%s)\n", E2FSPROGS_VERSION,
+			E2FSPROGS_DATE);
+		fuse_opt_add_arg(outargs, "--version");
+		fuse_main(outargs->argc, outargs->argv, &fs_ops, NULL);
+		exit(0);
+	}
+	return 1;
 }
 
 int main(int argc, char *argv[])
 {
+	struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
+	struct fuse2fs fctx;
 	errcode_t err;
 	char *tok, *arg, *logfile;
 	int i;
-	int readwrite = 1, panic_on_error = 0, minixdf = 0;
-	struct fuse2fs *ff;
 	char extra_args[BUFSIZ];
 	int ret = 0, flags = EXT2_FLAG_64BITS | EXT2_FLAG_EXCLUSIVE;
 
-	if (argc < 2) {
-		print_help(argv[0]);
-		return 1;
-	}
+	memset(&fctx, 0, sizeof(fctx));
+	fctx.magic = FUSE2FS_MAGIC;
 
-	for (i = 1; i < argc; i++) {
-		if (strcmp(argv[i], "--help") == 0) {
-			print_help(argv[0]);
-			return 1;
-		}
-	}
-
-	for (i = 1; i < argc - 1; i++) {
-		if (strcmp(argv[i], "-o"))
-			continue;
-		arg = argv[i + 1];
-		while ((tok = strtok(arg, ","))) {
-			arg = NULL;
-			if (!strcmp(tok, "ro"))
-				readwrite = 0;
-			else if (!strcmp(tok, "errors=panic"))
-				panic_on_error = 1;
-			else if (!strcmp(tok, "minixdf"))
-				minixdf = 1;
-		}
+	fuse_opt_parse(&args, &fctx, fuse2fs_opts, fuse2fs_opt_proc);
+	if (fctx.device == NULL) {
+		fprintf(stderr, "Missing ext4 device/image\n");
+		fprintf(stderr, "See '%s -h' for usage\n", argv[0]);
+		exit(1);
 	}
 
-	if (!readwrite)
+	if (fctx.ro)
 		printf("%s", _("Mounting read-only.\n"));
 
 #ifdef ENABLE_NLS
@@ -3678,57 +3735,48 @@ int main(int argc, char *argv[])
 #endif
 	add_error_table(&et_ext2_error_table);
 
-	ff = calloc(1, sizeof(*ff));
-	if (!ff) {
-		perror("init");
-		return 1;
-	}
-	ff->magic = FUSE2FS_MAGIC;
-	ff->panic_on_error = panic_on_error;
-	ff->minixdf = minixdf;
-
 	/* Set up error logging */
 	logfile = getenv("FUSE2FS_LOGFILE");
 	if (logfile) {
-		ff->err_fp = fopen(logfile, "a");
-		if (!ff->err_fp) {
+		fctx.err_fp = fopen(logfile, "a");
+		if (!fctx.err_fp) {
 			perror(logfile);
 			goto out_nofs;
 		}
 	} else
-		ff->err_fp = stderr;
+		fctx.err_fp = stderr;
 
 	/* Will we allow users to allocate every last block? */
 	if (getenv("FUSE2FS_ALLOC_ALL_BLOCKS")) {
 		printf(_("%s: Allowing users to allocate all blocks. "
-		       "This is dangerous!\n"), argv[1]);
-		ff->alloc_all_blocks = 1;
+		       "This is dangerous!\n"), fctx.device);
+		fctx.alloc_all_blocks = 1;
 	}
 
 	/* Start up the fs (while we still can use stdout) */
 	ret = 2;
-	if (readwrite)
+	if (!fctx.ro)
 		flags |= EXT2_FLAG_RW;
-	err = ext2fs_open2(argv[1], NULL, flags, 0, 0, unix_io_manager,
+	err = ext2fs_open2(fctx.device, NULL, flags, 0, 0, unix_io_manager,
 			   &global_fs);
 	if (err) {
-		printf(_("%s: %s.\n"), argv[1], error_message(err));
-		printf(_("Please run e2fsck -fy %s.\n"), argv[1]);
+		printf(_("%s: %s.\n"), fctx.device, error_message(err));
+		printf(_("Please run e2fsck -fy %s.\n"), fctx.device);
 		goto out_nofs;
 	}
-	ff->fs = global_fs;
-	global_fs->priv_data = ff;
+	fctx.fs = global_fs;
+	global_fs->priv_data = &fctx;
 
 	ret = 3;
 	if (ext2fs_has_feature_journal_needs_recovery(global_fs->super)) {
-		if (readwrite) {
-			printf(_("%s: recovering journal\n"), argv[1]);
+		if (!fctx.ro) {
+			printf(_("%s: recovering journal\n"), fctx.device);
 			err = ext2fs_run_ext3_journal(&global_fs);
 			if (err) {
-				printf(_("%s: %s.\n"), argv[1],
+				printf(_("%s: %s.\n"), fctx.device,
 				       error_message(err));
 				printf(_("Please run e2fsck -fy %s.\n"),
-				       argv[1]);
+				       fctx.device);
 				goto out;
 			}
 			ext2fs_clear_feature_journal_needs_recovery(global_fs->super);
@@ -3740,10 +3788,10 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	if (readwrite) {
+	if (!fctx.ro) {
 		if (ext2fs_has_feature_journal(global_fs->super))
 			printf(_("%s: Writing to the journal is not supported.\n"),
-			       argv[1]);
+			       fctx.device);
 		err = ext2fs_read_inode_bitmap(global_fs);
 		if (err) {
 			translate_error(global_fs, 0, err);
@@ -3779,19 +3827,27 @@ int main(int argc, char *argv[])
 	}
 
 	/* Initialize generation counter */
-	get_random_bytes(&ff->next_generation, sizeof(unsigned int));
+	get_random_bytes(&fctx.next_generation, sizeof(unsigned int));
 
-	/* Stuff in some fuse parameters of our own */
+	/* Set up default fuse parameters */
 	snprintf(extra_args, BUFSIZ, "-okernel_cache,subtype=ext4,use_ino,"
-		 "fsname=%s,attr_timeout=0,allow_other" FUSE_PLATFORM_OPTS,
+		 "fsname=%s,attr_timeout=0" FUSE_PLATFORM_OPTS,
 		 argv[1]);
-	argv[0] = argv[1];
-	argv[1] = argv[2];
-	argv[2] = extra_args;
+	if (fctx.no_default_opts == 0)
+		fuse_opt_add_arg(&args, extra_args);
+
+	if (fctx.debug) {
+		int	i;
+
+		printf("fuse arguments:");
+		for (i = 0; i < args.argc; i++)
+			printf(" '%s'", args.argv[i]);
+		printf("\n");
+	}
 
-	pthread_mutex_init(&ff->bfl, NULL);
-	fuse_main(argc, argv, &fs_ops, ff);
-	pthread_mutex_destroy(&ff->bfl);
+	pthread_mutex_init(&fctx.bfl, NULL);
+	fuse_main(args.argc, args.argv, &fs_ops, &fctx);
+	pthread_mutex_destroy(&fctx.bfl);
 
 	ret = 0;
 out:
@@ -3800,7 +3856,6 @@ out:
 		com_err(argv[0], err, "while closing fs");
 	global_fs = NULL;
 out_nofs:
-	free(ff);
 
 	return ret;
 }
-- 
2.5.0

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