klibc-utils: new applets: resume, nuke, minips

minips is a pure alias to ps, just in case someone needs 100% klibc-utils compat.
nuke is a primitive version of "rm -rf" without options and error checks. ~30 bytes.

resume is a tool for initramfs which resumes from a given block device.

function                                             old     new   delta
resume_main                                            -     582    +582
packed_usage                                       31640   31712     +72
nuke_main                                              -      28     +28
xstrtoull                                              -      24     +24
applet_names                                        2646    2665     +19
applet_main                                         1532    1544     +12
applet_suid                                           96      97      +1
applet_install_loc                                   192     193      +1
applet_flags                                          96      97      +1
------------------------------------------------------------------------------
(add/remove: 5/0 grow/shrink: 6/0 up/down: 740/0)             Total: 740 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

5 files changed, 192 insertions, 0 deletions

diff --git a/klibc-utils/Config.src b/klibc-utils/Config.src
new file mode 100644
index 000000000..fe7cb1315
--- /dev/null
+++ b/klibc-utils/Config.src
@@ -0,0 +1,10 @@
+#
+# For a description of the syntax of this configuration file,
+# see scripts/kbuild/config-language.txt.
+#
+
+menu "klibc-utils"
+
+INSERT
+
+endmenu
diff --git a/klibc-utils/Kbuild.src b/klibc-utils/Kbuild.src
new file mode 100644
index 000000000..6b4fb7470
--- /dev/null
+++ b/klibc-utils/Kbuild.src
@@ -0,0 +1,9 @@
+# Makefile for busybox
+#
+# Copyright (C) 1999-2005 by Erik Andersen <andersen@codepoet.org>
+#
+# Licensed under GPLv2, see file LICENSE in this source tree.
+
+lib-y:=
+
+INSERT
diff --git a/klibc-utils/minips.c b/klibc-utils/minips.c
new file mode 100644
index 000000000..96ce8868d
--- /dev/null
+++ b/klibc-utils/minips.c
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2017 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+//config:config MINIPS
+//config:	bool "minips (11 kb)"
+//config:	default n  # for god's sake, just use "ps" name in your scripts
+//config:	help
+//config:	Alias to "ps".
+
+/* applet abd kbuild hooks are in ps.c */
diff --git a/klibc-utils/nuke.c b/klibc-utils/nuke.c
new file mode 100644
index 000000000..363e03cce
--- /dev/null
+++ b/klibc-utils/nuke.c
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2017 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+//config:config NUKE
+//config:	bool "nuke"
+//config:	default y
+//config:	help
+//config:	Alias to "rm -rf".
+
+//applet:IF_NUKE(APPLET_NOEXEC(nuke, nuke, BB_DIR_BIN, BB_SUID_DROP, nuke))
+
+//kbuild:lib-$(CONFIG_NUKE) += nuke.o
+
+//usage:#define nuke_trivial_usage
+//usage:       "DIR..."
+//usage:#define nuke_full_usage "\n\n"
+//usage:       "Resursively remove DIRs"
+
+#include "libbb.h"
+
+/* This is a NOEXEC applet. Be very careful! */
+
+int nuke_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int nuke_main(int argc UNUSED_PARAM, char **argv)
+{
+// klibc-utils do not check opts, will try to delete "-dir" args
+	//opt = getopt32(argv, "");
+	//argv += optind;
+
+	while (*++argv) {
+#if 0
+// klibc-utils do not check this, will happily operate on ".."
+		const char *base = bb_get_last_path_component_strip(*argv);
+		if (DOT_OR_DOTDOT(base)) {
+			bb_error_msg("can't remove '.' or '..'");
+			continue;
+		}
+#endif
+		remove_file(*argv, FILEUTILS_FORCE | FILEUTILS_RECUR);
+	}
+
+// klibc-utils do not indicate errors
+	return EXIT_SUCCESS;
+}
diff --git a/klibc-utils/resume.c b/klibc-utils/resume.c
new file mode 100644
index 000000000..de142f350
--- /dev/null
+++ b/klibc-utils/resume.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2017 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+//config:config RESUME
+//config:	bool "resume"
+//config:	default y
+//config:	help
+//config:	Resume from saved "suspend-to-disk" image
+
+//applet:IF_RESUME(APPLET_NOEXEC(resume, resume, BB_DIR_BIN, BB_SUID_DROP, resume))
+
+//kbuild:lib-$(CONFIG_RESUME) += resume.o
+
+#include "libbb.h"
+
+/* This is a NOEXEC applet. Be very careful! */
+
+/* name_to_dev_t() in klibc-utils supports extended device name formats,
+ * apart from the usual case where /dev/NAME already exists.
+ *
+ * - device number in hexadecimal represents itself (in dev_t layout).
+ * - device number in major:minor decimal represents itself.
+ * - if block device (or partition) with this name is found in sysfs.
+ * - if /dev/ prefix is not given, it is assumed.
+ *
+ * klibc-utils also recognizes these, but they don't work
+ * for "resume" tool purposes (thus we don't support them (yet?)):
+ * - /dev/nfs
+ * - /dev/ram (alias to /dev/ram0)
+ * - /dev/mtd
+ */
+static dev_t name_to_dev_t(const char *devname)
+{
+	char devfile[sizeof(int)*3 * 2 + 4];
+	char *sysname;
+	unsigned major_num, minor_num;
+	struct stat st;
+	int r;
+
+	if (strncmp(devname, "/dev/", 5) != 0) {
+		char *cptr;
+
+		cptr = strchr(devname, ':');
+		if (cptr) {
+			/* Colon-separated decimal device number? */
+			*cptr = '\0';
+			major_num = bb_strtou(devname, NULL, 10);
+			if (!errno)
+				minor_num = bb_strtou(cptr + 1, NULL, 10);
+			*cptr = ':';
+			if (!errno)
+				return makedev(major_num, minor_num);
+		} else {
+			/* Hexadecimal device number? */
+			dev_t res = (dev_t) bb_strtoul(devname, NULL, 16);
+			if (!errno)
+				return res;
+		}
+
+		devname = xasprintf("/dev/%s", devname);
+	}
+	/* Now devname is always "/dev/FOO" */
+
+	if (stat(devname, &st) == 0 && S_ISBLK(st.st_mode))
+		return st.st_rdev;
+
+	/* Full blockdevs as well as partitions may be visible
+	 * in /sys/class/block/ even if /dev is not populated.
+	 */
+	sysname = xasprintf("/sys/class/block/%s/dev", devname + 5);
+	r = open_read_close(sysname, devfile, sizeof(devfile) - 1);
+	//free(sysname);
+	if (r > 0) {
+		devfile[r] = '\0';
+		if (sscanf(devfile, "%u:%u", &major_num, &minor_num) == 2) {
+			return makedev(major_num, minor_num);
+		}
+	}
+
+	return (dev_t) 0;
+}
+
+//usage:#define resume_trivial_usage
+//usage:       "BLOCKDEV [OFFSET]"
+//usage:#define resume_full_usage "\n"
+//usage:   "\n""Restore system state from 'suspend-to-disk' data in BLOCKDEV"
+
+int resume_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int resume_main(int argc UNUSED_PARAM, char **argv)
+{
+	unsigned long long ofs;
+	dev_t resume_device;
+	char *s;
+	int fd;
+
+	argv++;
+	if (!argv[0])
+		bb_show_usage();
+
+	resume_device = name_to_dev_t(argv[0]);
+	if (major(resume_device) == 0) {
+		bb_error_msg_and_die("invalid resume device: %s", argv[0]);
+	}
+	ofs = (argv[1] ? xstrtoull(argv[1], 0) : 0);
+
+	fd = xopen("/sys/power/resume", O_WRONLY);
+	s = xasprintf("%u:%u:%llu", major(resume_device), minor(resume_device), ofs);
+
+	xwrite_str(fd, s);
+	/* if write() returns, resume did not succeed */
+
+	return EXIT_FAILURE; /* klibc-utils exits -1 aka 255 */
+}