From cf04a7775a4e8ff6fd28c768be9daa3d83dd382e Mon Sep 17 00:00:00 2001 From: Ricardo Branco Date: Tue, 23 Apr 2024 15:47:56 -0600 Subject: [PATCH] swapon: Do not overwrite Linux swap header Reviewed by: imp, jhb Pull Request: https://github.com/freebsd/freebsd-src/pull/1084 --- sbin/swapon/Makefile | 2 ++ sbin/swapon/extern.h | 5 ++++ sbin/swapon/swaplinux.c | 66 +++++++++++++++++++++++++++++++++++++++++ sbin/swapon/swapon.c | 54 ++++++++++++++++++++++++++++++++- 4 files changed, 126 insertions(+), 1 deletion(-) create mode 100644 sbin/swapon/extern.h create mode 100644 sbin/swapon/swaplinux.c diff --git a/sbin/swapon/Makefile b/sbin/swapon/Makefile index 27808aed585..930e938e5b0 100644 --- a/sbin/swapon/Makefile +++ b/sbin/swapon/Makefile @@ -6,6 +6,8 @@ LINKS= ${BINDIR}/swapon ${BINDIR}/swapoff LINKS+= ${BINDIR}/swapon ${BINDIR}/swapctl MLINKS= swapon.8 swapoff.8 MLINKS+=swapon.8 swapctl.8 +SRCS= swapon.c swaplinux.c +HDRS+= extern.h LIBADD= util diff --git a/sbin/swapon/extern.h b/sbin/swapon/extern.h new file mode 100644 index 00000000000..cb33dbbee95 --- /dev/null +++ b/sbin/swapon/extern.h @@ -0,0 +1,5 @@ +/*- + * SPDX-License-Identifier: BSD-3-Clause + */ + +int is_linux_swap(const char *); diff --git a/sbin/swapon/swaplinux.c b/sbin/swapon/swaplinux.c new file mode 100644 index 00000000000..d01a94345e6 --- /dev/null +++ b/sbin/swapon/swaplinux.c @@ -0,0 +1,66 @@ +/*- + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include +#include +#include +#include +#include + +#include "extern.h" + +/* + * Definitions and structure taken from + * https://github.com/util-linux/util-linux/blob/master/include/swapheader.h + */ + +#define SWAP_VERSION 1 +#define SWAP_UUID_LENGTH 16 +#define SWAP_LABEL_LENGTH 16 +#define SWAP_SIGNATURE "SWAPSPACE2" +#define SWAP_SIGNATURE_SZ (sizeof(SWAP_SIGNATURE) - 1) + +struct swap_header_v1_2 { + char bootbits[1024]; /* Space for disklabel etc. */ + uint32_t version; + uint32_t last_page; + uint32_t nr_badpages; + unsigned char uuid[SWAP_UUID_LENGTH]; + char volume_name[SWAP_LABEL_LENGTH]; + uint32_t padding[117]; + uint32_t badpages[1]; +}; + +typedef union { + struct swap_header_v1_2 header; + struct { + uint8_t reserved[4096 - SWAP_SIGNATURE_SZ]; + char signature[SWAP_SIGNATURE_SZ]; + } tail; +} swhdr_t; + +#define sw_version header.version +#define sw_volume_name header.volume_name +#define sw_signature tail.signature + +int +is_linux_swap(const char *name) +{ + uint8_t buf[4096]; + swhdr_t *hdr = (swhdr_t *) buf; + int fd; + + fd = open(name, O_RDONLY); + if (fd == -1) + return (-1); + + if (read(fd, buf, 4096) != 4096) { + close(fd); + return (-1); + } + close(fd); + + return (hdr->sw_version == SWAP_VERSION && + !memcmp(hdr->sw_signature, SWAP_SIGNATURE, SWAP_SIGNATURE_SZ)); +} diff --git a/sbin/swapon/swapon.c b/sbin/swapon/swapon.c index 26a7dc22654..0f2ad1f5e21 100644 --- a/sbin/swapon/swapon.c +++ b/sbin/swapon/swapon.c @@ -54,10 +54,15 @@ #include #include +#include "extern.h" + +#define _PATH_GNOP "/sbin/gnop" + static void usage(void) __dead2; static const char *swap_on_off(const char *, int, char *); static const char *swap_on_off_gbde(const char *, int); static const char *swap_on_off_geli(const char *, char *, int); +static const char *swap_on_off_linux(const char *, int); static const char *swap_on_off_md(const char *, char *, int); static const char *swap_on_off_sfile(const char *, int); static void swaplist(int, int, int); @@ -250,8 +255,13 @@ swap_on_off(const char *name, int doingall, char *mntops) return (swap_on_off_geli(name, mntops, doingall)); } - /* Swap on special file. */ free(basebuf); + + /* Linux swap */ + if (is_linux_swap(name)) + return (swap_on_off_linux(name, doingall)); + + /* Swap on special file. */ return (swap_on_off_sfile(name, doingall)); } @@ -466,6 +476,48 @@ swap_on_off_geli(const char *name, char *mntops, int doingall) return (swap_on_off_sfile(name, doingall)); } +static const char * +swap_on_off_linux(const char *name, int doingall) +{ + const char *ret; + char *nopname; + size_t nopnamelen; + int error; + + if (which_prog == SWAPON) { + /* Skip the header for Linux swap partitions */ + error = run_cmd(NULL, "%s create -o 4096 %s", _PATH_GNOP, + name); + if (error) { + warnx("gnop (create) error: %s", name); + return (NULL); + } + } + + /* Append ".nop" to name */ + nopnamelen = strlen(name) + sizeof(".nop"); + nopname = (char *) malloc(nopnamelen); + if (nopname == NULL) + err(1, "malloc()"); + (void)strlcpy(nopname, name, nopnamelen); + (void)strlcat(nopname, ".nop", nopnamelen); + + ret = swap_on_off_sfile(nopname, doingall); + + if (which_prog == SWAPOFF) { + error = run_cmd(NULL, "%s destroy %s", _PATH_GNOP, nopname); + if (error) { + warnx("gnop (destroy) error: %s", name); + free(nopname); + return (NULL); + } + } + + free(nopname); + + return (ret); +} + static const char * swap_on_off_md(const char *name, char *mntops, int doingall) { -- 2.45.0