brctl: eliminate stray data object

brctl: use constant fd to reduce parameter passing
runsvdir: do not use data/bss
od: reuse bb_argv_dash
last: do not go into endless loop on read error
mount: make it not fail scripts/find_bad_common_bufsiz check
dc: add INIT_G() (no-op for dc, but we want uniform usage of "G trick")

function                                             old     new   delta
runsvdir_main                                       1646    1672     +26
set_pgrp                                               1       -      -1
exitsoon                                               1       -      -1
check                                                679     678      -1
svnum                                                  4       -      -4
svdir                                                  4       -      -4
sv                                                     4       -      -4
stamplog                                               4       -      -4
rploglen                                               4       -      -4
rplog                                                  4       -      -4
mount_main                                           995     988      -7
static.default_file_list                               8       -      -8
pfd                                                    8       -      -8
logpipe                                                8       -      -8
static.info                                           20       -     -20
brctl_main                                           767     739     -28
------------------------------------------------------------------------------
(add/remove: 0/12 grow/shrink: 1/3 up/down: 26/-106)          Total: -80 bytes
   text    data     bss     dec     hex filename
 793327     662    7412  801401   c3a79 busybox_old
 793329     641    7372  801342   c3a3e busybox_unstripped

2 files changed, 11 insertions, 10 deletions

diff --git a/miscutils/dc.c b/miscutils/dc.c
index 68ecd8a3f..612937556 100644
--- a/miscutils/dc.c
+++ b/miscutils/dc.c
@@ -19,6 +19,8 @@ enum { STACK_SIZE = (COMMON_BUFSIZE - offsetof(struct globals, stack)) / sizeof(
 #define pointer   (G.pointer   )
 #define base      (G.base      )
 #define stack     (G.stack     )
+#define INIT_G() do { \
+} while (0)
 
 
 static void push(double a)
@@ -194,6 +196,8 @@ static char *get_token(char **buffer)
 int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int dc_main(int argc ATTRIBUTE_UNUSED, char **argv)
 {
+        INIT_G();
+
         argv++;
         if (!argv[0]) {
                 /* take stuff from stdin if no args are given */
diff --git a/miscutils/last.c b/miscutils/last.c
index f46d4ca0c..f823a1385 100644
--- a/miscutils/last.c
+++ b/miscutils/last.c
@@ -39,9 +39,8 @@ int last_main(int argc, char **argv ATTRIBUTE_UNUSED)
         file = xopen(bb_path_wtmp_file, O_RDONLY);
 
         printf("%-10s %-14s %-18s %-12.12s %s\n", "USER", "TTY", "HOST", "LOGIN", "TIME");
-        while ((n = safe_read(file, (void*)&ut, sizeof(struct utmp))) != 0) {
-
-                if (n != sizeof(struct utmp)) {
+        while ((n = full_read(file, &ut, sizeof(ut))) > 0) {
+                if (n != sizeof(ut)) {
                         bb_perror_msg_and_die("short read");
                 }
 
@@ -53,16 +52,14 @@ int last_main(int argc, char **argv ATTRIBUTE_UNUSED)
                         else if (strncmp(ut.ut_user, "runlevel", 7) == 0)
                                 ut.ut_type = RUN_LVL;
                 } else {
-                        if (!ut.ut_name[0] || strcmp(ut.ut_name, "LOGIN") == 0 ||
-                                        ut.ut_name[0] == 0)
-                        {
+                        if (ut.ut_name[0] == '\0' || strcmp(ut.ut_name, "LOGIN") == 0) {
                                 /* Don't bother.  This means we can't find how long
                                  * someone was logged in for.  Oh well. */
                                 continue;
                         }
-                        if (ut.ut_type != DEAD_PROCESS &&
-                                        ut.ut_name[0] && ut.ut_line[0])
-                        {
+                        if (ut.ut_type != DEAD_PROCESS
+                         && ut.ut_name[0] && ut.ut_line[0]
+                        ) {
                                 ut.ut_type = USER_PROCESS;
                         }
                         if (strcmp(ut.ut_name, "date") == 0) {
@@ -71,7 +68,7 @@ int last_main(int argc, char **argv ATTRIBUTE_UNUSED)
                         }
                 }
 
-                if (ut.ut_type!=USER_PROCESS) {
+                if (ut.ut_type != USER_PROCESS) {
                         switch (ut.ut_type) {
                                 case OLD_TIME:
                                 case NEW_TIME: