blockdev: code shrink

function                                             old     new   delta
bdcmd_names                                            -      82     +82
bdcmd_ioctl                                            -      44     +44
bdcmd_flags                                            -      11     +11
blockdev_main                                        273     258     -15
bdcommands                                           176       -    -176
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 0/1 up/down: 137/-191)          Total: -54 bytes
   text	   data	    bss	    dec	    hex	filename
 982326	    485	   7296	 990107	  f1b9b	busybox_old
 982272	    485	   7296	 990053	  f1b65	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 58 insertions, 81 deletions

diff --git a/util-linux/blockdev.c b/util-linux/blockdev.c
index 5d8e465b4..e9b5b8bf9 100644
--- a/util-linux/blockdev.c
+++ b/util-linux/blockdev.c
@@ -34,6 +34,35 @@
 #include "libbb.h"
 #include <linux/fs.h>
 
+/* Takes less space is separate arrays than one array of struct */
+static const char bdcmd_names[] ALIGN1 =
+        "setro"     "\0"
+#define CMD_SETRO 0
+        "setrw"     "\0"
+        "getro"     "\0"
+        "getss"     "\0"
+        "getbsz"    "\0"
+        "setbsz"    "\0"
+#define CMD_SETBSZ 5
+        "getsz"     "\0"
+        "getsize"   "\0"
+        "getsize64" "\0"
+        "flushbufs" "\0"
+        "rereadpt"  "\0"
+;
+static const uint32_t bdcmd_ioctl[] = {
+        BLKROSET,       //setro
+        BLKROSET,       //setrw
+        BLKROGET,       //getro
+        BLKSSZGET,      //getss
+        BLKBSZGET,      //getbsz
+        BLKBSZSET,      //setbsz
+        BLKGETSIZE64,   //getsz
+        BLKGETSIZE,     //getsize
+        BLKGETSIZE64,   //getsize64
+        BLKFLSBUF,      //flushbufs
+        BLKRRPART,      //rereadpt
+};
 enum {
         ARG_NONE   = 0,
         ARG_INT    = 1,
@@ -46,83 +75,26 @@ enum {
         FL_NORESULT = 8,
         FL_SCALE512 = 16,
 };
-
-struct bdc {
-        uint32_t   ioc;                       /* ioctl code */
-        const char name[sizeof("flushbufs")]; /* "--setfoo" wothout "--" */
-        uint8_t    flags;
-        int8_t     argval;                    /* default argument value */
+static const uint8_t bdcmd_flags[] ALIGN1 = {
+        ARG_INT + FL_NORESULT,             //setro
+        ARG_INT + FL_NORESULT,             //setrw
+        ARG_INT,                           //getro
+        ARG_INT,                           //getss
+        ARG_INT,                           //getbsz
+        ARG_INT + FL_NORESULT + FL_USRARG, //setbsz
+        ARG_U64 + FL_SCALE512,             //getsz
+        ARG_ULONG,                         //getsize
+        ARG_U64,                           //getsize64
+        ARG_NONE + FL_NORESULT,            //flushbufs
+        ARG_NONE + FL_NORESULT,            //rereadpt
 };
 
-static const struct bdc bdcommands[] = {
-        {
-                .ioc = BLKROSET,
-                .name = "setro",
-                .flags = ARG_INT + FL_NORESULT,
-                .argval = 1,
-        },{
-                .ioc = BLKROSET,
-                .name = "setrw",
-                .flags = ARG_INT + FL_NORESULT,
-                .argval = 0,
-        },{
-                .ioc = BLKROGET,
-                .name = "getro",
-                .flags = ARG_INT,
-                .argval = -1,
-        },{
-                .ioc = BLKSSZGET,
-                .name = "getss",
-                .flags = ARG_INT,
-                .argval = -1,
-        },{
-                .ioc = BLKBSZGET,
-                .name = "getbsz",
-                .flags = ARG_INT,
-                .argval = -1,
-        },{
-                .ioc = BLKBSZSET,
-                .name = "setbsz",
-                .flags = ARG_INT + FL_NORESULT + FL_USRARG,
-                .argval = 0,
-        },{
-                .ioc = BLKGETSIZE64,
-                .name = "getsz",
-                .flags = ARG_U64 + FL_SCALE512,
-                .argval = -1,
-        },{
-                .ioc = BLKGETSIZE,
-                .name = "getsize",
-                .flags = ARG_ULONG,
-                .argval = -1,
-        },{
-                .ioc = BLKGETSIZE64,
-                .name = "getsize64",
-                .flags = ARG_U64,
-                .argval = -1,
-        },{
-                .ioc = BLKFLSBUF,
-                .name = "flushbufs",
-                .flags = ARG_NONE + FL_NORESULT,
-                .argval = 0,
-        },{
-                .ioc = BLKRRPART,
-                .name = "rereadpt",
-                .flags = ARG_NONE + FL_NORESULT,
-                .argval = 0,
-        }
-};
-
-static const struct bdc *find_cmd(const char *s)
+static unsigned find_cmd(const char *s)
 {
-        const struct bdc *bdcmd = bdcommands;
         if (s[0] == '-' && s[1] == '-') {
-                s += 2;
-                do {
-                        if (strcmp(s, bdcmd->name) == 0)
-                                return bdcmd;
-                        bdcmd++;
-                } while (bdcmd != bdcommands + ARRAY_SIZE(bdcommands));
+                int n = index_in_strings(bdcmd_names, s + 2);
+                if (n >= 0)
+                        return n;
         }
         bb_show_usage();
 }
@@ -130,7 +102,8 @@ static const struct bdc *find_cmd(const char *s)
 int blockdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int blockdev_main(int argc UNUSED_PARAM, char **argv)
 {
-        const struct bdc *bdcmd;
+        unsigned bdcmd;
+        unsigned flags;
         int fd;
         uint64_t u64;
         union {
@@ -144,10 +117,13 @@ int blockdev_main(int argc UNUSED_PARAM, char **argv)
                 bb_show_usage();
 
         bdcmd = find_cmd(*argv);
-
-        u64 = (int)bdcmd->argval;
-        if (bdcmd->flags & FL_USRARG)
+        /* setrw translates to BLKROSET(0), most other ioctls don't care... */
+        /* ...setro will do BLKROSET(1) */
+        u64 = (bdcmd == CMD_SETRO);
+        if (bdcmd == CMD_SETBSZ) {
+                /* ...setbsz is BLKBSZSET(bytes) */
                 u64 = xatoi_positive(*++argv);
+        }
 
         argv++;
         if (!argv[0] || argv[1])
@@ -155,6 +131,7 @@ int blockdev_main(int argc UNUSED_PARAM, char **argv)
         fd = xopen(argv[0], O_RDONLY);
 
         ioctl_val_on_stack.u64 = u64;
+        flags = bdcmd_flags[bdcmd];
 #if BB_BIG_ENDIAN
         /* Store data properly wrt data size.
          * (1) It's no-op for little-endian.
@@ -162,7 +139,7 @@ int blockdev_main(int argc UNUSED_PARAM, char **argv)
          * 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) {
+        switch (flags & ARG_MASK) {
         case ARG_INT:
                 ioctl_val_on_stack.i = (int)u64;
                 break;
@@ -174,17 +151,17 @@ int blockdev_main(int argc UNUSED_PARAM, char **argv)
         }
 #endif
 
-        if (ioctl(fd, bdcmd->ioc, &ioctl_val_on_stack.u64) == -1)
+        if (ioctl(fd, bdcmd_ioctl[bdcmd], &ioctl_val_on_stack.u64) == -1)
                 bb_simple_perror_msg_and_die(*argv);
 
         /* Fetch it into register(s) */
         u64 = ioctl_val_on_stack.u64;
 
-        if (bdcmd->flags & FL_SCALE512)
+        if (flags & FL_SCALE512)
                 u64 >>= 9;
 
         /* Zero- or one-extend the value if needed, then print */
-        switch (bdcmd->flags & (ARG_MASK+FL_NORESULT)) {
+        switch (flags & (ARG_MASK+FL_NORESULT)) {
         case ARG_INT:
                 /* Smaller code when we use long long
                  * (gcc tail-merges printf call)