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authorDenys Vlasenko2017-08-18 19:15:29 +0200
committerDenys Vlasenko2017-08-18 19:15:29 +0200
commitab77e81a8527fa11a4f9392d97c2da037d6f4f98 (patch)
treed11608662dd14b776a4c4d30a6039d476231ca58 /klibc-utils/resume.c
parent79747415d6db1f85389247522304c941b4287f9b (diff)
downloadbusybox-ab77e81a8527fa11a4f9392d97c2da037d6f4f98.zip
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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>
Diffstat (limited to 'klibc-utils/resume.c')
-rw-r--r--klibc-utils/resume.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/klibc-utils/resume.c b/klibc-utils/resume.c
new file mode 100644
index 0000000..de142f3
--- /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 */
+}