mkswap: always use header from control struct

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/disk-utils/mkswap.c b/disk-utils/mkswap.c
index b0e76cfd90518bcb83aa50750481fdd2d1929b63..7a4b53e84af7ab4679a047cb4532f54c930eb88a 100644 (file)
--- a/disk-utils/mkswap.c
+++ b/disk-utils/mkswap.c
@@ -19,6 +19,7 @@
 #include <sys/stat.h>
 #include <errno.h>
 #include <getopt.h>
+#include <assert.h>
 #ifdef HAVE_LIBSELINUX
 #include <selinux/selinux.h>
 #include <selinux/context.h>
@@ -49,7 +50,7 @@
 #define SELINUX_SWAPFILE_TYPE  "swapfile_t"
 
 struct mkswap_control {
-       struct swap_header_v1_2 *hdr;
+       struct swap_header_v1_2 *hdr;           /* swap header */
        void                    *signature_page;/* buffer with swap header */
 
        char                    *device_name;
@@ -68,8 +69,7 @@ struct mkswap_control {
                                force:1;        /* --force */
 };
 
-static void
-init_signature_page(struct mkswap_control *ctl)
+static void init_signature_page(struct mkswap_control *ctl)
 {
        const int kernel_pagesize = getpagesize();
 
@@ -86,7 +86,17 @@ init_signature_page(struct mkswap_control *ctl)
                ctl->pagesize = ctl->user_pagesize;
        } else
                ctl->pagesize = kernel_pagesize;
+
        ctl->signature_page = (unsigned long *) xcalloc(1, ctl->pagesize);
+       ctl->hdr = (struct swap_header_v1_2 *) ctl->signature_page;
+}
+
+static void deinit_signature_page(struct mkswap_control *ctl)
+{
+       free(ctl->signature_page);
+
+       ctl->hdr = NULL;
+       ctl->signature_page = NULL;
 }
 
 static void
@@ -100,19 +110,25 @@ write_signature(const struct mkswap_control *ctl)
 static void
 write_uuid_and_label(const struct mkswap_control *ctl)
 {
-       struct swap_header_v1_2 *h;
+       assert(ctl);
+       assert(ctl->hdr);
 
-       h = (struct swap_header_v1_2 *) ctl->signature_page;
+       /* set UUID */
        if (ctl->uuid)
-               memcpy(h->uuid, ctl->uuid, sizeof(h->uuid));
+               memcpy(ctl->hdr->uuid, ctl->uuid, sizeof(ctl->hdr->uuid));
+
+       /* set LABEL */
        if (ctl->opt_label) {
-               xstrncpy(h->volume_name, ctl->opt_label, sizeof(h->volume_name));
-               if (strlen(ctl->opt_label) > strlen(h->volume_name))
+               xstrncpy(ctl->hdr->volume_name,
+                        ctl->opt_label, sizeof(ctl->hdr->volume_name));
+               if (strlen(ctl->opt_label) > strlen(ctl->hdr->volume_name))
                        warnx(_("Label was truncated."));
        }
+
+       /* report resuls */
        if (ctl->uuid || ctl->opt_label) {
                if (ctl->opt_label)
-                       printf("LABEL=%s, ", h->volume_name);
+                       printf("LABEL=%s, ", ctl->hdr->volume_name);
                else
                        printf(_("no label, "));
 #ifdef HAVE_LIBUUID
@@ -147,25 +163,27 @@ static void __attribute__ ((__noreturn__)) usage(FILE *out)
        exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 }
 
-static void
-page_bad(struct mkswap_control *ctl, unsigned int page)
+static void page_bad(struct mkswap_control *ctl, unsigned int page)
 {
-       struct swap_header_v1_2 *p = (struct swap_header_v1_2 *)ctl->signature_page;
-       const unsigned long max_badpages = (ctl->pagesize - 1024 - 128 * sizeof(int) - 10) / sizeof(int);
+       const unsigned long max_badpages =
+               (ctl->pagesize - 1024 - 128 * sizeof(int) - 10) / sizeof(int);
 
        if (ctl->nbadpages == max_badpages)
                errx(EXIT_FAILURE, _("too many bad pages: %lu"), max_badpages);
-       p->badpages[ctl->nbadpages] = page;
+
+       ctl->hdr->badpages[ctl->nbadpages] = page;
        ctl->nbadpages++;
 }
 
-static void
-check_blocks(struct mkswap_control *ctl)
+static void check_blocks(struct mkswap_control *ctl)
 {
        unsigned int current_page = 0;
        int do_seek = 1;
        char *buffer;
 
+       assert(ctl);
+       assert(ctl->fd > -1);
+
        buffer = xmalloc(ctl->pagesize);
        while (current_page < ctl->npages) {
                ssize_t rc;
@@ -289,7 +307,7 @@ wipe_device(struct mkswap_control *ctl)
 
 int
 main(int argc, char **argv) {
-       struct mkswap_control ctl = { .fd = -1, 0 };
+       struct mkswap_control ctl = { .fd = -1 };
        struct stat statbuf;
        int c;
        unsigned long long goodpages;
@@ -432,7 +450,7 @@ main(int argc, char **argv) {
 
        wipe_device(&ctl);
 
-       ctl.hdr = (struct swap_header_v1_2 *) ctl.signature_page;
+       assert(ctl.hdr);
        ctl.hdr->version = version;
        ctl.hdr->last_page = ctl.npages - 1;
        ctl.hdr->nr_badpages = ctl.nbadpages;
@@ -455,7 +473,9 @@ main(int argc, char **argv) {
                err(EXIT_FAILURE,
                        _("%s: unable to write signature page"),
                        ctl.device_name);
-       free(ctl.signature_page);
+
+       deinit_signature_page(&ctl);
+
 #ifdef HAVE_LIBSELINUX
        if (S_ISREG(statbuf.st_mode) && is_selinux_enabled() > 0) {
                security_context_t context_string;