ubase

suckless linux base utils
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commit 891949ee919c407a9c26f6422324249c0a78f6a1
parent ade390a29f3612f6e5d9a0f77a1f337e18b4ac8a
Author: Jan Tatje <jan@jnt.io>
Date:   Sat Nov 29 21:09:39 +0000

Add swaplabel(8)

Diffstat:
LICENSE | 1+
Makefile | 2++
TODO | 1-
swaplabel.8 | 11+++++++++++
swaplabel.c | 80+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 94 insertions(+), 1 deletion(-)
diff --git a/LICENSE b/LICENSE @@ -9,6 +9,7 @@ MIT/X Consortium License © 2014 Hiltjo Posthuma <hiltjo@codemadness.org> © 2014 Laslo Hunhold <dev@frign.de> © 2014 Roberto E. Vargas Caballero <k0ga@shike2.com> +© 2014 Jan Tatje <jan@jnt.io> Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), diff --git a/Makefile b/Makefile @@ -70,6 +70,7 @@ SRC = \ rmmod.c \ stat.c \ su.c \ + swaplabel.c \ swapoff.c \ swapon.c \ switch_root.c \ @@ -125,6 +126,7 @@ MAN8 = \ pivot_root.8 \ readahead.8 \ rmmod.8 \ + swaplabel.8 \ swapoff.8 \ swapon.8 \ switch_root.8 \ diff --git a/TODO b/TODO @@ -4,7 +4,6 @@ Tools vmstat top Better ps support -swaplabel losetup lspci mkswap [-L] diff --git a/swaplabel.8 b/swaplabel.8 @@ -0,0 +1,11 @@ +.TH SWAPLABEL 8 ubase-VERSION +.SH NAME +\fBswaplabel\fR - set the label of a swap filesystem +.SH SYNOPSIS +\fBswaplabel\fR [\fB-L\fI label\fR] \fIdevice\fR +.SH DESCRIPTION +\fBswaplabel\fR is used to change the label of a swap device or file. +.SH OPTIONS +.TP +\fB-L\fR +Change the label. diff --git a/swaplabel.c b/swaplabel.c @@ -0,0 +1,80 @@ +/* See LICENSE file for copyright and license details. */ +#include <sys/types.h> + +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "util.h" + +#define SWAP_MAGIC1 "SWAPSPACE2" +#define SWAP_MAGIC2 "SWAP-SPACE" +#define SWAP_MAGIC_LENGTH (10) +#define SWAP_MAGIC_OFFSET (sysconf(_SC_PAGESIZE) - SWAP_MAGIC_LENGTH) +#define SWAP_LABEL_LENGTH (16) +#define SWAP_LABEL_OFFSET (1024 + 4 + 4 + 4 + 16) + +static void +usage(void) +{ + eprintf("usage: %s [-L label] device\n", argv0); +} + +int +main(int argc, char *argv[]) +{ + int setlabel = 0; + int fd = -1; + char magic[10] = { 0 }; + char *label = NULL; + char *device = NULL; + int i; + + ARGBEGIN { + case 'L': + setlabel = 1; + label = EARGF(usage()); + break; + default: + usage(); + } ARGEND; + + if (argc < 1) + usage(); + device = argv[0]; + + fd = open(device, O_RDWR); + if (fd < 0) + eprintf("open %s:", device); + + if (lseek(fd, SWAP_MAGIC_OFFSET, SEEK_SET) != SWAP_MAGIC_OFFSET) + eprintf("failed seeking to magic position:"); + if (read(fd, magic, SWAP_MAGIC_LENGTH) != SWAP_MAGIC_LENGTH) + eprintf("reading magic failed:"); + if (memcmp(magic, SWAP_MAGIC1, 10) && memcmp(magic, SWAP_MAGIC2, 10)) + eprintf("%s: is not a swap partition\n", device); + if (lseek(fd, SWAP_LABEL_OFFSET, SEEK_SET) != SWAP_LABEL_OFFSET) + eprintf("failed seeking to label position:"); + + if (!setlabel) { + label = emalloc(SWAP_LABEL_LENGTH); + if (read(fd, label, SWAP_LABEL_LENGTH) != SWAP_LABEL_LENGTH) + eprintf("reading label failed:"); + for (i = 0; i < SWAP_LABEL_LENGTH && label[i] != '\0'; i++) + if (i == (SWAP_LABEL_LENGTH - 1) && label[i] != '\0') + eprintf("invalid label\n"); + printf("label: %s\n", label); + free(label); + } else { + if (strlen(label) + 1 > SWAP_LABEL_LENGTH) + eprintf("label too long\n"); + if (write(fd, label, strlen(label) + 1) != (ssize_t)strlen(label) + 1) + eprintf("writing label failed:"); + } + + fsync(fd); + close(fd); + return 0; +}