diff --git a/Makefile b/Makefile index d267535..150ca13 100644 --- 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/swaplabel.8 b/swaplabel.8 new file mode 100644 index 0000000..d442626 --- /dev/null +++ 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 new file mode 100644 index 0000000..99467c8 --- /dev/null +++ b/swaplabel.c @@ -0,0 +1,94 @@ +/* See LICENSE file for copyright and license details. */ +#include + +#include +#include +#include +#include +#include + +#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; + + ARGBEGIN { + case 'L': + setlabel = 1; + label = ARGF(); + break; + default: + usage(); + } ARGEND; + + if (argc < 1) + usage(); + + device = argv[0]; + + fd = open(device, O_RDWR); + + if (fd < 0) + eprintf("error: could not open device.\n"); + + if (lseek(fd, SWAP_MAGIC_OFFSET, SEEK_SET) != SWAP_MAGIC_OFFSET) + eprintf("error: failed seeking to magic position.\n"); + + if (read(fd, magic, SWAP_MAGIC_LENGTH) != SWAP_MAGIC_LENGTH) + eprintf("error: reading magic failed.\n"); + + if (memcmp(magic, SWAP_MAGIC1, 10) && memcmp(magic, SWAP_MAGIC2, 10)) + eprintf("error: %s is not a swap partition.\n", device); + + if (lseek(fd, SWAP_LABEL_OFFSET, SEEK_SET) != SWAP_LABEL_OFFSET) + eprintf("error: failed seeking to label position.\n"); + + if (!setlabel) { + label = malloc(SWAP_LABEL_LENGTH * sizeof(char)); + if (!label) + eprintf("error: malloc failed"); + + if (read(fd, label, SWAP_LABEL_LENGTH) != SWAP_LABEL_LENGTH) + eprintf("error: reading label failed.\n"); + + for (int i = 0; i < SWAP_LABEL_LENGTH && label[i] != '\0'; i++) { + if (i == (SWAP_LABEL_LENGTH - 1) && label[i] != '\0') + eprintf("error: invalid label.\n"); + } + + printf("label: %s\n", label); + + free(label); + } + + if (setlabel) { + if ((strlen(label)+1) > SWAP_LABEL_LENGTH) + eprintf("error: label too long.\n"); + + if (write(fd, label, (strlen(label)+1)) < 0) + eprintf("error: writing label failed.\n"); + } + + fsync(fd); + close(fd); +} +