|
@@ -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 */
|
|
|
+}
|