blockdev: code shrink

function                                             old     new   delta
blockdev_main                                        292     255     -37

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

1 files changed, 34 insertions, 22 deletions

diff --git a/util-linux/blockdev.c b/util-linux/blockdev.c
index a780d2238..29c288a15 100644
--- a/util-linux/blockdev.c
+++ b/util-linux/blockdev.c
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2010 Sergey Naumov <sknaumov@gmail.com>
  *
- * Licensed under GPLv2, see file LICENSE in this source tree.
+ * Licensed under GPLv2, see file License in this tarball for details.
  */
 
 //applet:IF_BLOCKDEV(APPLET(blockdev, _BB_DIR_SBIN, _BB_SUID_DROP))
@@ -39,7 +39,8 @@ enum {
         ARG_NONE   = 0,
         ARG_INT    = 1,
         ARG_ULONG  = 2,
-        ARG_ULLONG = 3,
+        /* Yes, BLKGETSIZE64 takes pointer to uint64_t, not ullong! */
+        ARG_U64    = 3,
         ARG_MASK   = 3,
 
         FL_USRARG   = 4, /* argument is provided by user */
@@ -92,7 +93,7 @@ static const struct bdc bdcommands[] = {
         },{
                 .ioc = BLKGETSIZE64,
                 .name = "getsize64",
-                .flags = ARG_ULLONG,
+                .flags = ARG_U64,
                 .argval = -1,
         },{
                 .ioc = BLKFLSBUF,
@@ -125,55 +126,66 @@ int blockdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int blockdev_main(int argc, char **argv)
 {
         const struct bdc *bdcmd;
-        void *ioctl_ptr;
         int fd;
-        int iarg;
-        unsigned long lu;
-        unsigned long long llu;
+        uint64_t u64;
+        union {
+                int i;
+                unsigned long lu;
+                uint64_t u64;
+        } ioctl_val_on_stack;
 
         if ((unsigned)(argc - 3) > 1) /* must have 2 or 3 args */
                 bb_show_usage();
 
         bdcmd = find_cmd(*++argv);
 
-        llu = (int)bdcmd->argval;
+        u64 = (int)bdcmd->argval;
         if (bdcmd->flags & FL_USRARG)
-                llu = xatoi_positive(*++argv);
-        lu = llu;
-        iarg = llu;
+                u64 = xatoi_positive(*++argv);
 
         if (!*++argv || argv[1])
                 bb_show_usage();
         fd = xopen(*argv, O_RDONLY);
 
-        ioctl_ptr = NULL;
+        ioctl_val_on_stack.u64 = u64;
+#if BB_BIG_ENDIAN
+        /* Store data properly wrt data size.
+         * (1) It's no-op for little-endian.
+         * (2) it's no-op for 0 and -1. Only --setro uses arg != 0 and != -1,
+         * and it is ARG_INT. --setbsz USER_VAL is also ARG_INT.
+         * Thus, we don't need to handle ARG_ULONG.
+         */
         switch (bdcmd->flags & ARG_MASK) {
         case ARG_INT:
-                ioctl_ptr =  &iarg;
+                ioctl_val_on_stack.i = (int)u64;
                 break;
+# if 0 /* unused */
         case ARG_ULONG:
-                ioctl_ptr = &lu;
-                break;
-        case ARG_ULLONG:
-                ioctl_ptr = &llu;
+                ioctl_val_on_stack.lu = (unsigned long)u64;
                 break;
+# endif
         }
+#endif
 
-        if (ioctl(fd, bdcmd->ioc, ioctl_ptr) == -1)
+        if (ioctl(fd, bdcmd->ioc, &ioctl_val_on_stack.u64) == -1)
                 bb_simple_perror_msg_and_die(*argv);
 
+        /* Fetch it into register(s) */
+        u64 = ioctl_val_on_stack.u64;
+
+        /* Zero- or one-extend the value if needed, then print */
         switch (bdcmd->flags & (ARG_MASK+FL_NORESULT)) {
         case ARG_INT:
                 /* Smaller code when we use long long
                  * (gcc tail-merges printf call)
                  */
-                printf("%lld\n", (long long)iarg);
+                printf("%lld\n", (long long)(int)u64);
                 break;
         case ARG_ULONG:
-                llu = lu;
+                u64 = (unsigned long)u64;
                 /* FALLTHROUGH */
-        case ARG_ULLONG:
-                printf("%llu\n", llu);
+        case ARG_U64:
+                printf("%llu\n", (unsigned long long)u64);
                 break;
         }