/* * Copyright (c) 2017 Denys Vlasenko <vda.linux@googlemail.com> * * Licensed under GPLv2, see file LICENSE in this source tree. */ //config:config RESUME //config: bool "resume (3.2 kb)" //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 */ }