better shared strings trick

   text	   data	    bss	    dec	    hex	filename
 861980	    441	   7540	 869961	  d4649	busybox_old
 861914	    441	   7540	 869895	  d4607	busybox_unstripped

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

8 files changed, 33 insertions, 43 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 6fb0438f5..4b69c855f 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1573,12 +1573,22 @@ void bb_progress_update(bb_progress_t *p, const char *curfile,
                         off_t totalsize) FAST_FUNC;
 
 extern const char *applet_name;
+
+/* Some older linkers don't perform string merging, we used to have common strings
+ * as global arrays to do it by hand. But:
+ * (1) newer linkers do it themselves,
+ * (2) however, they DONT merge string constants with global arrays,
+ * even if the value is the same (!). Thus global arrays actually
+ * increased size a bit: for example, "/etc/passwd" string from libc
+ * wasn't merged with bb_path_passwd_file[] array!
+ * Therefore now we use #defines.
+ */
 /* "BusyBox vN.N.N (timestamp or extra_version)" */
 extern const char bb_banner[];
 extern const char bb_msg_memory_exhausted[];
 extern const char bb_msg_invalid_date[];
-extern const char bb_msg_read_error[];
-extern const char bb_msg_write_error[];
+#define bb_msg_read_error "read error"
+#define bb_msg_write_error "write error"
 extern const char bb_msg_unknown[];
 extern const char bb_msg_can_not_create_raw_socket[];
 extern const char bb_msg_perm_denied_are_you_root[];
@@ -1588,18 +1598,23 @@ extern const char bb_msg_invalid_arg[];
 extern const char bb_msg_standard_input[];
 extern const char bb_msg_standard_output[];
 
-extern const char bb_str_default[];
 /* NB: (bb_hexdigits_upcase[i] | 0x20) -> lowercase hex digit */
 extern const char bb_hexdigits_upcase[];
 
-extern const char bb_path_mtab_file[];
-extern const char bb_path_passwd_file[];
-extern const char bb_path_shadow_file[];
-extern const char bb_path_gshadow_file[];
-extern const char bb_path_group_file[];
-extern const char bb_path_motd_file[];
 extern const char bb_path_wtmp_file[];
-extern const char bb_dev_null[];
+
+/* Busybox mount uses either /proc/mounts or /etc/mtab to
+ * get the list of currently mounted filesystems */
+#define bb_path_mtab_file IF_FEATURE_MTAB_SUPPORT("/etc/mtab")IF_NOT_FEATURE_MTAB_SUPPORT("/proc/mounts")
+
+#define bb_path_passwd_file "/etc/passwd"
+#define bb_path_shadow_file "/etc/shadow"
+#define bb_path_gshadow_file "/etc/gshadow"
+#define bb_path_group_file "/etc/group"
+
+#define bb_path_motd_file "/etc/motd"
+
+#define bb_dev_null "/dev/null"
 extern const char bb_busybox_exec_path[];
 /* util-linux manpage says /sbin:/bin:/usr/sbin:/usr/bin,
  * but I want to save a few bytes here */
diff --git a/libbb/Kbuild.src b/libbb/Kbuild.src
index 5db4d8a62..b02fcfe74 100644
--- a/libbb/Kbuild.src
+++ b/libbb/Kbuild.src
@@ -64,7 +64,6 @@ lib-y += md5.o
 #lib-y += md5prime.o
 lib-y += messages.o
 lib-y += mode_string.o
-lib-y += mtab_file.o
 lib-y += obscure.o
 lib-y += parse_mode.o
 lib-y += parse_config.o
diff --git a/libbb/inet_common.c b/libbb/inet_common.c
index b47259089..e031ddf9b 100644
--- a/libbb/inet_common.c
+++ b/libbb/inet_common.c
@@ -23,7 +23,7 @@ int FAST_FUNC INET_resolve(const char *name, struct sockaddr_in *s_in, int hostf
         s_in->sin_port = 0;
 
         /* Default is special, meaning 0.0.0.0. */
-        if (!strcmp(name, bb_str_default)) {
+        if (strcmp(name, "default") == 0) {
                 s_in->sin_addr.s_addr = INADDR_ANY;
                 return 1;
         }
@@ -109,7 +109,7 @@ char* FAST_FUNC INET_rresolve(struct sockaddr_in *s_in, int numeric, uint32_t ne
         if (ad == INADDR_ANY) {
                 if ((numeric & 0x0FFF) == 0) {
                         if (numeric & 0x8000)
-                                return xstrdup(bb_str_default);
+                                return xstrdup("default");
                         return xstrdup("*");
                 }
         }
@@ -205,7 +205,7 @@ char* FAST_FUNC INET6_rresolve(struct sockaddr_in6 *sin6, int numeric)
         }
         if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
                 if (numeric & 0x8000)
-                        return xstrdup(bb_str_default);
+                        return xstrdup("default");
                 return xstrdup("*");
         }
 
diff --git a/libbb/messages.c b/libbb/messages.c
index 44b39942f..66e466ffa 100644
--- a/libbb/messages.c
+++ b/libbb/messages.c
@@ -24,8 +24,6 @@ const char bb_banner[] ALIGN1 = BANNER;
 
 const char bb_msg_memory_exhausted[] ALIGN1 = "memory exhausted";
 const char bb_msg_invalid_date[] ALIGN1 = "invalid date '%s'";
-const char bb_msg_write_error[] ALIGN1 = "write error";
-const char bb_msg_read_error[] ALIGN1 = "read error";
 const char bb_msg_unknown[] ALIGN1 = "(unknown)";
 const char bb_msg_can_not_create_raw_socket[] ALIGN1 = "can't create raw socket";
 const char bb_msg_perm_denied_are_you_root[] ALIGN1 = "permission denied (are you root?)";
@@ -35,15 +33,8 @@ const char bb_msg_invalid_arg[] ALIGN1 = "invalid argument '%s' to '%s'";
 const char bb_msg_standard_input[] ALIGN1 = "standard input";
 const char bb_msg_standard_output[] ALIGN1 = "standard output";
 
-const char bb_str_default[] ALIGN1 = "default";
 const char bb_hexdigits_upcase[] ALIGN1 = "0123456789ABCDEF";
 
-const char bb_path_passwd_file[] ALIGN1 = "/etc/passwd";
-const char bb_path_shadow_file[] ALIGN1 = "/etc/shadow";
-const char bb_path_group_file[] ALIGN1 = "/etc/group";
-const char bb_path_gshadow_file[] ALIGN1 = "/etc/gshadow";
-const char bb_path_motd_file[] ALIGN1 = "/etc/motd";
-const char bb_dev_null[] ALIGN1 = "/dev/null";
 const char bb_busybox_exec_path[] ALIGN1 = CONFIG_BUSYBOX_EXEC_PATH;
 const char bb_default_login_shell[] ALIGN1 = LIBBB_DEFAULT_LOGIN_SHELL;
 /* util-linux manpage says /sbin:/bin:/usr/sbin:/usr/bin,
diff --git a/libbb/mtab_file.c b/libbb/mtab_file.c
deleted file mode 100644
index add990ded..000000000
--- a/libbb/mtab_file.c
+++ /dev/null
@@ -1,15 +0,0 @@
-/* vi: set sw=4 ts=4: */
-/*
- * Utility routines.
- *
- * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
- *
- * Licensed under GPLv2 or later, see file LICENSE in this source tree.
- */
-
-#include "libbb.h"
-
-/* Busybox mount uses either /proc/mounts or /etc/mtab to
- * get the list of currently mounted filesystems */
-const char bb_path_mtab_file[] ALIGN1 =
-IF_FEATURE_MTAB_SUPPORT("/etc/mtab")IF_NOT_FEATURE_MTAB_SUPPORT("/proc/mounts");
diff --git a/networking/ifconfig.c b/networking/ifconfig.c
index 853910f67..da2635ce0 100644
--- a/networking/ifconfig.c
+++ b/networking/ifconfig.c
@@ -370,7 +370,7 @@ int ifconfig_main(int argc UNUSED_PARAM, char **argv)
 #endif
                                                 sai.sin_family = AF_INET;
                                                 sai.sin_port = 0;
-                                                if (!strcmp(host, bb_str_default)) {
+                                                if (strcmp(host, "default") == 0) {
                                                         /* Default is special, meaning 0.0.0.0. */
                                                         sai.sin_addr.s_addr = INADDR_ANY;
                                                 }
diff --git a/networking/libiproute/utils.c b/networking/libiproute/utils.c
index 5125617c7..2b646f0ea 100644
--- a/networking/libiproute/utils.c
+++ b/networking/libiproute/utils.c
@@ -64,7 +64,7 @@ int get_addr_1(inet_prefix *addr, char *name, int family)
 {
         memset(addr, 0, sizeof(*addr));
 
-        if (strcmp(name, bb_str_default) == 0
+        if (strcmp(name, "default") == 0
          || strcmp(name, "all") == 0
          || strcmp(name, "any") == 0
         ) {
@@ -103,7 +103,7 @@ static int get_prefix_1(inet_prefix *dst, char *arg, int family)
 
         memset(dst, 0, sizeof(*dst));
 
-        if (strcmp(arg, bb_str_default) == 0
+        if (strcmp(arg, "default") == 0
          || strcmp(arg, "all") == 0
          || strcmp(arg, "any") == 0
         ) {
diff --git a/networking/route.c b/networking/route.c
index c72e9457f..98567aaee 100644
--- a/networking/route.c
+++ b/networking/route.c
@@ -185,7 +185,7 @@ static NOINLINE void INET_setroute(int action, char **args)
 #endif
                 } else {
                         /* Default netmask. */
-                        netmask = bb_str_default;
+                        netmask = "default";
                 }
                 /* Prefer hostname lookup is -host flag (xflag==1) was given. */
                 isnet = INET_resolve(target, (struct sockaddr_in *) &rt.rt_dst,
@@ -346,7 +346,7 @@ static NOINLINE void INET6_setroute(int action, char **args)
                 /* We know args isn't NULL from the check in route_main. */
                 const char *target = *args++;
 
-                if (strcmp(target, bb_str_default) == 0) {
+                if (strcmp(target, "default") == 0) {
                         prefix_len = 0;
                         memset(&sa6, 0, sizeof(sa6));
                 } else {