lib/losetup: added file format support

losetup can set the file format of each loop device during
creation.

Signed-off-by: Manuel Bentele <development@manuel-bentele.de>

3 files changed, 151 insertions, 17 deletions

diff --git a/include/loopdev.h b/include/loopdev.h
index 0e3a7517a..bc68e526b 100644
--- a/include/loopdev.h
+++ b/include/loopdev.h
@@ -11,6 +11,14 @@
 #define LO_CRYPT_DES	2
 #define LO_CRYPT_CRYPTOAPI 18
 
+/*
+ * loop_info.lo_file_fmt_type
+ */
+#define LO_FILE_FMT_RAW		0
+#define LO_FILE_FMT_QCOW	1
+#define LO_FILE_FMT_VDI		2
+#define LO_FILE_FMT_VMDK	3
+
 #define LOOP_SET_FD		0x4C00
 #define LOOP_CLR_FD		0x4C01
 /*
@@ -64,6 +72,7 @@ struct loop_info64 {
 	uint8_t		lo_crypt_name[LO_NAME_SIZE];
 	uint8_t		lo_encrypt_key[LO_KEY_SIZE];
 	uint64_t	lo_init[2];
+	uint32_t	lo_file_fmt_type;
 };
 
 #define LOOPDEV_MAJOR		7	/* loop major number */
@@ -175,6 +184,7 @@ extern int loopcxt_ioctl_blocksize(struct loopdev_cxt *lc, uint64_t blocksize);
 int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset);
 int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit);
 int loopcxt_set_blocksize(struct loopdev_cxt *lc, uint64_t blocksize);
+int loopcxt_set_file_fmt_type(struct loopdev_cxt *lc, uint32_t file_fmt_type);
 int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags);
 int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename);
 
@@ -185,6 +195,8 @@ extern int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset);
 extern int loopcxt_get_blocksize(struct loopdev_cxt *lc, uint64_t *blocksize);
 extern int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size);
 extern int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type);
+extern int loopcxt_get_file_fmt_type(struct loopdev_cxt *lc, uint32_t* file_fmt_type);
+extern char *loopcxt_get_file_fmt_type_string(struct loopdev_cxt *lc);
 extern const char *loopcxt_get_crypt_name(struct loopdev_cxt *lc);
 extern int loopcxt_is_autoclear(struct loopdev_cxt *lc);
 extern int loopcxt_is_readonly(struct loopdev_cxt *lc);
@@ -205,4 +217,6 @@ extern int loopcxt_is_used(struct loopdev_cxt *lc,
                     uint64_t sizelimit,
                     int flags);
 
+extern int parse_file_fmt_type(const char *file_fmt_type_str, uint32_t *file_fmt_type);
+
 #endif /* UTIL_LINUX_LOOPDEV_H */
diff --git a/lib/loopdev.c b/lib/loopdev.c
index ede1b5cdc..676cc02f3 100644
--- a/lib/loopdev.c
+++ b/lib/loopdev.c
@@ -824,6 +824,75 @@ int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type)
 }
 
 /*
+ * @file_fmt_type_str: file format type string.
+ * @file_fmt_type: returns file format type from the given file format string.
+ *
+ * Returns: <0 on error, 0 on success
+ */
+int parse_file_fmt_type(const char *file_fmt_type_str, uint32_t *file_fmt_type)
+{
+	int rc = 0;
+
+	if (!strcmp(file_fmt_type_str, "RAW"))
+		*file_fmt_type = LO_FILE_FMT_RAW;
+	else if (!strcmp(file_fmt_type_str, "QCOW"))
+		*file_fmt_type = LO_FILE_FMT_QCOW;
+	else if (!strcmp(file_fmt_type_str, "VDI"))
+		*file_fmt_type = LO_FILE_FMT_VDI;
+	else if (!strcmp(file_fmt_type_str, "VMDK"))
+		*file_fmt_type = LO_FILE_FMT_VMDK;
+	else
+		rc = -EINVAL;
+
+	return rc;
+}
+
+/*
+ * @lc: context
+ * @file_fmt_type: returns file format type of the given device
+ *
+ * Returns: <0 on error, 0 on success
+ */
+int loopcxt_get_file_fmt_type(struct loopdev_cxt *lc, uint32_t* file_fmt_type)
+{
+	struct path_cxt *sysfs = loopcxt_get_sysfs(lc);
+	int rc = 0;
+
+	if (sysfs) {
+		/* check if file_fmt_type is accessible and supported by the kernel module */
+		char* file_fmt_str = NULL;
+		if (ul_path_read_string(sysfs, &file_fmt_str, "loop/file_fmt_type") == 0)
+			rc = parse_file_fmt_type(file_fmt_str, file_fmt_type);
+	} else
+		rc = -errno;
+
+	if (rc != 0 && loopcxt_ioctl_enabled(lc)) {
+		struct loop_info64 *lo = loopcxt_get_info(lc);
+		if (lo)
+			*file_fmt_type = lo->lo_file_fmt_type;
+	}
+
+	return 0;
+}
+
+/*
+ * @lc: context
+ *
+ * Returns (allocated) string with file format type of the current loop device.
+ */
+char *loopcxt_get_file_fmt_type_string(struct loopdev_cxt *lc)
+{
+	struct path_cxt *sysfs = loopcxt_get_sysfs(lc);
+	char *res = NULL;
+
+	if (sysfs)
+		ul_path_read_string(sysfs, &res, "loop/file_fmt_type");
+
+	DBG(CXT, ul_debugobj(lc, "loopcxt_get_file_fmt_type_string [%s]", res));
+	return res;
+}
+
+/*
  * @lc: context
  * @devno: returns crypt name
  *
@@ -1124,6 +1193,23 @@ int loopcxt_set_blocksize(struct loopdev_cxt *lc, uint64_t blocksize)
 
 /*
  * @lc: context
+ * @file_fmt_type: kernel LO_FILE_FMT_{RAW,QCOW,VDI,VMDK} flags
+ *
+ * The setting is removed by loopcxt_set_device() loopcxt_next()!
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int loopcxt_set_file_fmt_type(struct loopdev_cxt *lc, uint32_t file_fmt_type) {
+	if (!lc)
+		return -EINVAL;
+	lc->info.lo_file_fmt_type = file_fmt_type;
+
+	DBG(CXT, ul_debugobj(lc, "set file_fmt_type=%u", (unsigned) file_fmt_type));
+	return 0;
+}
+
+/*
+ * @lc: context
  * @flags: kernel LO_FLAGS_{READ_ONLY,USE_AOPS,AUTOCLEAR} flags
  *
  * The setting is removed by loopcxt_set_device() loopcxt_next()!
diff --git a/sys-utils/losetup.c b/sys-utils/losetup.c
index d862fd8e7..f455b49c3 100644
--- a/sys-utils/losetup.c
+++ b/sys-utils/losetup.c
@@ -43,6 +43,7 @@ enum {
 	COL_NAME = 0,
 	COL_AUTOCLR,
 	COL_BACK_FILE,
+	COL_FILE_FMT_TYPE,
 	COL_BACK_INO,
 	COL_BACK_MAJMIN,
 	COL_MAJMIN,
@@ -69,18 +70,19 @@ struct colinfo {
 };
 
 static struct colinfo infos[] = {
-	[COL_AUTOCLR]     = { "AUTOCLEAR",    1, SCOLS_FL_RIGHT, N_("autoclear flag set"), SCOLS_JSON_BOOLEAN},
-	[COL_BACK_FILE]   = { "BACK-FILE",  0.3, 0, N_("device backing file")},
-	[COL_BACK_INO]    = { "BACK-INO",     4, SCOLS_FL_RIGHT, N_("backing file inode number"), SCOLS_JSON_NUMBER},
-	[COL_BACK_MAJMIN] = { "BACK-MAJ:MIN", 6, 0, N_("backing file major:minor device number")},
-	[COL_NAME]        = { "NAME",      0.25, 0, N_("loop device name")},
-	[COL_OFFSET]      = { "OFFSET",       5, SCOLS_FL_RIGHT, N_("offset from the beginning"), SCOLS_JSON_NUMBER},
-	[COL_PARTSCAN]    = { "PARTSCAN",     1, SCOLS_FL_RIGHT, N_("partscan flag set"), SCOLS_JSON_BOOLEAN},
-	[COL_RO]          = { "RO",           1, SCOLS_FL_RIGHT, N_("read-only device"), SCOLS_JSON_BOOLEAN},
-	[COL_SIZELIMIT]   = { "SIZELIMIT",    5, SCOLS_FL_RIGHT, N_("size limit of the file in bytes"), SCOLS_JSON_NUMBER},
-	[COL_MAJMIN]      = { "MAJ:MIN",      3, 0, N_("loop device major:minor number")},
-	[COL_DIO]         = { "DIO",          1, SCOLS_FL_RIGHT, N_("access backing file with direct-io"), SCOLS_JSON_BOOLEAN},
-	[COL_LOGSEC]      = { "LOG-SEC",      4, SCOLS_FL_RIGHT, N_("logical sector size in bytes"), SCOLS_JSON_NUMBER},
+	[COL_AUTOCLR]       = { "AUTOCLEAR",    1, SCOLS_FL_RIGHT, N_("autoclear flag set"), SCOLS_JSON_BOOLEAN},
+	[COL_BACK_FILE]     = { "BACK-FILE",  0.3, 0, N_("device backing file")},
+	[COL_FILE_FMT_TYPE] = { "FILE-FORMAT",  1, 0, N_("backing file format")},
+	[COL_BACK_INO]      = { "BACK-INO",     4, SCOLS_FL_RIGHT, N_("backing file inode number"), SCOLS_JSON_NUMBER},
+	[COL_BACK_MAJMIN]   = { "BACK-MAJ:MIN", 6, 0, N_("backing file major:minor device number")},
+	[COL_NAME]          = { "NAME",      0.25, 0, N_("loop device name")},
+	[COL_OFFSET]        = { "OFFSET",       5, SCOLS_FL_RIGHT, N_("offset from the beginning"), SCOLS_JSON_NUMBER},
+	[COL_PARTSCAN]      = { "PARTSCAN",     1, SCOLS_FL_RIGHT, N_("partscan flag set"), SCOLS_JSON_BOOLEAN},
+	[COL_RO]            = { "RO",           1, SCOLS_FL_RIGHT, N_("read-only device"), SCOLS_JSON_BOOLEAN},
+	[COL_SIZELIMIT]     = { "SIZELIMIT",    5, SCOLS_FL_RIGHT, N_("size limit of the file in bytes"), SCOLS_JSON_NUMBER},
+	[COL_MAJMIN]        = { "MAJ:MIN",      3, 0, N_("loop device major:minor number")},
+	[COL_DIO]           = { "DIO",          1, SCOLS_FL_RIGHT, N_("access backing file with direct-io"), SCOLS_JSON_BOOLEAN},
+	[COL_LOGSEC]        = { "LOG-SEC",      4, SCOLS_FL_RIGHT, N_("logical sector size in bytes"), SCOLS_JSON_NUMBER},
 };
 
 static int columns[ARRAY_SIZE(infos) * 2] = {-1};
@@ -120,11 +122,16 @@ static int printf_loopdev(struct loopdev_cxt *lc)
 	ino_t ino = 0;
 	char *fname;
 	uint32_t type;
+	char *file_fmt_str;
 
 	fname = loopcxt_get_backing_file(lc);
 	if (!fname)
 		return -EINVAL;
 
+	file_fmt_str = loopcxt_get_file_fmt_type_string(lc);
+	if (!file_fmt_str)
+		return -EINVAL;
+
 	if (loopcxt_get_backing_devno(lc, &dev) == 0)
 		loopcxt_get_backing_inode(lc, &ino);
 
@@ -141,6 +148,9 @@ static int printf_loopdev(struct loopdev_cxt *lc)
 
 		if (loopcxt_get_sizelimit(lc, &x) == 0 && x)
 				printf(_(", sizelimit %ju"), x);
+
+		printf(_(", file-format %s"), file_fmt_str);
+
 		goto done;
 	}
 
@@ -162,6 +172,8 @@ static int printf_loopdev(struct loopdev_cxt *lc)
 			printf(_(", encryption %s (type %u)"), e, type);
 	}
 
+	printf(_(", file-format %s"), file_fmt_str);
+
 done:
 	free(fname);
 	printf("\n");
@@ -241,6 +253,9 @@ static int set_scols_data(struct loopdev_cxt *lc, struct libscols_line *ln)
 		case COL_BACK_FILE:
 			p = loopcxt_get_backing_file(lc);
 			break;
+		case COL_FILE_FMT_TYPE:
+			p = loopcxt_get_file_fmt_type_string(lc);
+			break;
 		case COL_OFFSET:
 			if (loopcxt_get_offset(lc, &x) == 0)
 				xasprintf(&np, "%jd", x);
@@ -424,6 +439,7 @@ static void __attribute__((__noreturn__)) usage(void)
 	fputs(_(" -r, --read-only               set up a read-only loop device\n"), out);
 	fputs(_("     --direct-io[=<on|off>]    open backing file with O_DIRECT\n"), out);
 	fputs(_("     --show                    print device name after setup (with -f)\n"), out);
+	fputs(_(" -t, --type                    set file format type of the loop device\n"), out);
 	fputs(_(" -v, --verbose                 verbose mode\n"), out);
 
 	/* output options */
@@ -473,7 +489,7 @@ static void warn_size(const char *filename, uint64_t size, uint64_t offset, int
 static int create_loop(struct loopdev_cxt *lc,
 		       int nooverlap, int lo_flags, int flags,
 		       const char *file, uint64_t offset, uint64_t sizelimit,
-		       uint64_t blocksize)
+		       uint64_t blocksize, uint32_t file_fmt_type)
 {
 	int hasdev = loopcxt_has_device(lc);
 	int rc = 0;
@@ -568,6 +584,12 @@ static int create_loop(struct loopdev_cxt *lc,
 			warn(_("%s: failed to use backing file"), file);
 			break;
 		}
+
+		if ((rc = loopcxt_set_file_fmt_type(lc, file_fmt_type))) {
+			warn(_("failed to use backing file format type"));
+			break;
+		}
+
 		errno = 0;
 		rc = loopcxt_setup_device(lc);
 		if (rc == 0)
@@ -595,6 +617,8 @@ int main(int argc, char **argv)
 	char *outarg = NULL;
 	int list = 0;
 	unsigned long use_dio = 0, set_dio = 0, set_blocksize = 0;
+	int use_file_fmt_type = 0;
+	uint32_t file_fmt_type = 0;
 
 	enum {
 		OPT_SIZELIMIT = CHAR_MAX + 1,
@@ -625,6 +649,7 @@ int main(int argc, char **argv)
 		{ "direct-io",    optional_argument, NULL, OPT_DIO       },
 		{ "raw",          no_argument,       NULL, OPT_RAW       },
 		{ "show",         no_argument,       NULL, OPT_SHOW      },
+		{ "type",         required_argument, NULL, 't'           },
 		{ "verbose",      no_argument,       NULL, 'v'           },
 		{ "version",      no_argument,       NULL, 'V'           },
 		{ NULL, 0, NULL, 0 }
@@ -647,7 +672,7 @@ int main(int argc, char **argv)
 	if (loopcxt_init(&lc, 0))
 		err(EXIT_FAILURE, _("failed to initialize loopcxt"));
 
-	while ((c = getopt_long(argc, argv, "ab:c:d:Dfhj:JlLno:O:PrvV",
+	while ((c = getopt_long(argc, argv, "ab:c:d:Dfhj:JlLno:O:Prt:vV",
 				longopts, NULL)) != -1) {
 
 		err_exclusive_options(c, longopts, excl, excl_st);
@@ -725,6 +750,14 @@ int main(int argc, char **argv)
 			if (optarg)
 				use_dio = parse_switch(optarg, _("argument error"), "on", "off", NULL);
 			break;
+		case 't':
+			if (optarg) {
+				if (parse_file_fmt_type(optarg, &file_fmt_type) == 0)
+					use_file_fmt_type = 1;
+				else
+					errx(EXIT_FAILURE, _("failed to parse file format type"));
+			}
+			break;
 		case 'v':
 			break;
 		case OPT_SIZELIMIT:			/* --sizelimit */
@@ -763,6 +796,7 @@ int main(int argc, char **argv)
 		columns[ncolumns++] = COL_AUTOCLR;
 		columns[ncolumns++] = COL_RO;
 		columns[ncolumns++] = COL_BACK_FILE;
+		columns[ncolumns++] = COL_FILE_FMT_TYPE;
 		columns[ncolumns++] = COL_DIO;
 		columns[ncolumns++] = COL_LOGSEC;
 	}
@@ -822,10 +856,10 @@ int main(int argc, char **argv)
 	}
 
 	if (act != A_CREATE &&
-	    (sizelimit || lo_flags || showdev))
+	    (sizelimit || lo_flags || showdev || use_file_fmt_type))
 		errx(EXIT_FAILURE,
 			_("the options %s are allowed during loop device setup only"),
-			"--{sizelimit,partscan,read-only,show}");
+			"--{sizelimit,partscan,read-only,show,type}");
 
 	if ((flags & LOOPDEV_FL_OFFSET) &&
 	    act != A_CREATE && (act != A_SHOW || !file))
@@ -838,7 +872,7 @@ int main(int argc, char **argv)
 	switch (act) {
 	case A_CREATE:
 		res = create_loop(&lc, no_overlap, lo_flags, flags, file,
-				  offset, sizelimit, blocksize);
+				  offset, sizelimit, blocksize, file_fmt_type);
 		if (res == 0) {
 			if (showdev)
 				printf("%s\n", loopcxt_get_device(&lc));