libfdisk: add sample-fdisk-mkpart binary

For example:
	# sample-fdisk-mkpart --device /dev/sdc 1M 2M 3M - 5M

	# fdisk -l /dev/sdc
	...
	Device     Boot Start    End Sectors Size Id Type
	/dev/sdc1        2048   4095    2048   1M 83 Linux
	/dev/sdc2        4096   8191    4096   2M 83 Linux
	/dev/sdc3        8192  14335    6144   3M 83 Linux
	/dev/sdc4       14336 204799  190464  93M  5 Extended
	/dev/sdc5       16384  26623   10240   5M 83 Linux

Addresses: https://github.com/karelzak/util-linux/issues/204
Signed-off-by: Karel Zak <kzak@redhat.com>

libfdisk/Makemodule.am

@@ -1,6 +1,7 @@
 if BUILD_LIBFDISK
 
 include libfdisk/src/Makemodule.am
+include libfdisk/samples/Makemodule.am
 
 if ENABLE_GTK_DOC
 # Docs uses separate Makefiles

libfdisk/samples/Makemodule.am

@@ -0,0 +1,11 @@
+
+check_PROGRAMS += \
+	sample-fdisk-mkpart
+
+sample_fdisk_cflags = $(AM_CFLAGS) $(NO_UNUSED_WARN_CFLAGS) \
+                      -I$(ul_libfdisk_incdir)
+sample_fdisk_ldadd = $(LDADD) libfdisk.la
+
+sample_fdisk_mkpart_SOURCES = libfdisk/samples/mkpart.c
+sample_fdisk_mkpart_LDADD = $(sample_fdisk_ldadd) libcommon.la
+sample_fdisk_mkpart_CFLAGS = $(sample_fdisk_cflags)

libfdisk/samples/mkpart.c

@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2017 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <getopt.h>
+
+#include "c.h"
+#include "nls.h"
+#include "strutils.h"
+#include "xalloc.h"
+
+#include "libfdisk.h"
+
+static int ask_callback(struct fdisk_context *cxt __attribute__((__unused__)),
+			struct fdisk_ask *ask,
+			void *data)
+{
+	switch(fdisk_ask_get_type(ask)) {
+	case FDISK_ASKTYPE_INFO:
+		fputs(fdisk_ask_print_get_mesg(ask), stdout);
+		fputc('\n', stdout);
+		break;
+	case FDISK_ASKTYPE_WARNX:
+		fflush(stdout);
+		fputs(fdisk_ask_print_get_mesg(ask), stderr);
+		fputc('\n', stderr);
+		break;
+	case FDISK_ASKTYPE_WARN:
+		fflush(stdout);
+		fputs(fdisk_ask_print_get_mesg(ask), stderr);
+		errno = fdisk_ask_print_get_errno(ask);
+		fprintf(stderr, ": %m\n");
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	struct fdisk_context *cxt;
+	struct fdisk_partition *pa;
+	const char *label = NULL, *device = NULL;
+	int n = 0, c;
+	unsigned int sectorsize;
+
+	static const struct option longopts[] = {
+		{ "label",  required_argument, 0, 'x' },
+		{ "device", required_argument, 0, 'd' },
+		{ "help",   no_argument, 0, 'h' },
+		{ NULL, 0, 0, 0 },
+	};
+
+	setlocale(LC_ALL, "");	/* just to have enable UTF8 chars */
+
+	fdisk_init_debug(0);
+
+	while((c = getopt_long(argc, argv, "x:d:h", longopts, NULL)) != -1) {
+		switch(c) {
+		case 'x':
+			label = optarg;
+			break;
+		case 'd':
+			device = optarg;
+			break;
+		case 'h':
+			printf("%s [options] <size> ...", program_invocation_short_name);
+			fputs(USAGE_SEPARATOR, stdout);
+			fputs("Make disklabel and partitions.\n", stdout);
+			fputs(USAGE_OPTIONS, stdout);
+			fputs(" -x, --label <dos,gpt,...>    disk label type\n", stdout);
+			fputs(" -d, --device <path>          block device\n", stdout);
+			fputs(" -h, --help                   this help\n", stdout);
+			fputs(USAGE_SEPARATOR, stdout);
+			return EXIT_SUCCESS;
+		}
+	}
+
+	if (!device)
+		errx(EXIT_FAILURE, "no device specified");
+	if (!label)
+		label = "dos";
+
+	cxt = fdisk_new_context();
+	if (!cxt)
+		err_oom();
+	fdisk_set_ask(cxt, ask_callback, NULL);
+
+	pa = fdisk_new_partition();
+	if (!pa)
+		err_oom();
+
+	if (fdisk_assign_device(cxt, device, 0))
+		err(EXIT_FAILURE, "failed to assign device");
+	if (fdisk_create_disklabel(cxt, "dos"))
+		err(EXIT_FAILURE, "failed to create disk label");
+
+	sectorsize = fdisk_get_sector_size(cxt);
+
+	while (optind < argc) {
+		int rc;
+		uint64_t size;
+		const char *str = argv[optind];
+
+		/* defaults */
+		fdisk_partition_start_follow_default(pa, 1);
+		fdisk_partition_end_follow_default(pa, 1);
+
+		/* set size */
+		if (isdigit(*str)) {
+			size = strtosize_or_err(argv[optind], "failed to parse partition size");
+			fdisk_partition_set_size(pa, size / sectorsize);
+			fdisk_partition_end_follow_default(pa, 0);
+
+		} else if (*str == '-') {
+			fdisk_partition_end_follow_default(pa, 1);
+		}
+
+		if (fdisk_is_label(cxt, DOS)) {
+			/* For MBR we want to avoid primary/logical dialog.
+			 * This is possible by explicitly specified partition
+			 * number, <4 means primary, >=4 means logical.
+			 */
+			fdisk_partition_partno_follow_default(pa, 0);
+			fdisk_partition_set_partno(pa, n);
+
+			/* Make sure last primary partition is extended if user
+			 * wants more than 4 partitions.
+			 */
+			if (n == 3 && optind + 1 < argc) {
+				struct fdisk_parttype *type =
+					fdisk_label_parse_parttype(
+							fdisk_get_label(cxt, NULL), "05");
+				if (!type)
+					err_oom();
+				fdisk_partition_set_type(pa, type);
+				fdisk_unref_parttype(type);
+			}
+		} else
+			fdisk_partition_partno_follow_default(pa, 1);
+
+
+		rc = fdisk_add_partition(cxt, pa, NULL);
+		if (rc) {
+			errno = -rc;
+			err(EXIT_FAILURE, "failed to add #%d partition", n + 1);
+		}
+
+		fdisk_reset_partition(pa);
+		optind++;
+		n++;
+	}
+
+	if (fdisk_write_disklabel(cxt))
+		err(EXIT_FAILURE, "failed to write disk label");
+
+	fdisk_deassign_device(cxt, 1);
+	fdisk_unref_context(cxt);
+	fdisk_unref_partition(pa);
+
+	return EXIT_SUCCESS;
+}