From fad2b86c9e7eaadb973b50a1bc0e2accc1a96cfd Mon Sep 17 00:00:00 2001
From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Thu, 31 May 2007 22:16:38 +0000
Subject: [PATCH] use "glibc errno" trick not only for ash, but for entire
 busybox (add/remove: 1/1 grow/shrink: 37/37 up/down: 139/-228)        Total:
 -89 bytes

---
 applets/applets.c                    |  9 +++++++++
 archival/libunarchive/data_skip.c    |  6 +-----
 archival/libunarchive/seek_by_jump.c |  5 -----
 coreutils/mv.c                       |  3 ---
 debianutils/mktemp.c                 |  5 -----
 include/libbb.h                      |  8 ++++++++
 libbb/error_msg.c                    |  4 ----
 libbb/perror_msg.c                   |  4 ----
 libbb/run_shell.c                    | 13 +++----------
 libbb/safe_write.c                   |  5 -----
 loginutils/login.c                   |  1 -
 miscutils/devfsd.c                   | 11 -----------
 networking/libiproute/libnetlink.c   |  8 +-------
 shell/ash.c                          | 11 -----------
 util-linux/ipcs.c                    |  8 +-------
 util-linux/setarch.c                 |  5 -----
 16 files changed, 23 insertions(+), 83 deletions(-)

diff --git a/applets/applets.c b/applets/applets.c
index e905ebec4..bd3704394 100644
--- a/applets/applets.c
+++ b/applets/applets.c
@@ -641,10 +641,19 @@ void run_applet_and_exit(const char *name, char **argv)
 }
 
 
+#ifdef __GLIBC__
+/* Make it reside in R/W memory: */
+int *const bb_errno __attribute__ ((section (".data")));
+#endif
+
 int main(int argc, char **argv)
 {
 	const char *s;
 
+#ifdef __GLIBC__
+	(*(int **)&bb_errno) = __errno_location();
+#endif
+
 #if !BB_MMU
 	/* NOMMU re-exec trick sets high-order bit in first byte of name */
 	if (argv[0][0] & 0x80) {
diff --git a/archival/libunarchive/data_skip.c b/archival/libunarchive/data_skip.c
index dc3505a56..d9778da2e 100644
--- a/archival/libunarchive/data_skip.c
+++ b/archival/libunarchive/data_skip.c
@@ -3,12 +3,8 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <sys/types.h>
-#include <errno.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include "unarchive.h"
 #include "libbb.h"
+#include "unarchive.h"
 
 void data_skip(archive_handle_t *archive_handle)
 {
diff --git a/archival/libunarchive/seek_by_jump.c b/archival/libunarchive/seek_by_jump.c
index d605f61dd..6cd256418 100644
--- a/archival/libunarchive/seek_by_jump.c
+++ b/archival/libunarchive/seek_by_jump.c
@@ -3,11 +3,6 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <sys/types.h>
-#include <errno.h>
-#include <unistd.h>
-#include <stdlib.h>
-
 #include "libbb.h"
 #include "unarchive.h"
 
diff --git a/coreutils/mv.c b/coreutils/mv.c
index ad36051f9..8d9c9827a 100644
--- a/coreutils/mv.c
+++ b/coreutils/mv.c
@@ -15,10 +15,7 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <unistd.h>
 #include <dirent.h>
-#include <errno.h>
-#include <stdlib.h>
 #include <getopt.h> /* struct option */
 #include "libbb.h"
 #include "libcoreutils/coreutils.h"
diff --git a/debianutils/mktemp.c b/debianutils/mktemp.c
index 966257aed..9e7ef7b4c 100644
--- a/debianutils/mktemp.c
+++ b/debianutils/mktemp.c
@@ -10,11 +10,6 @@
  */
 
 #include "libbb.h"
-#include <stdio.h>
-#include <errno.h>
-#include <string.h>
-#include <unistd.h>
-#include <stdlib.h>
 
 int mktemp_main(int argc, char **argv);
 int mktemp_main(int argc, char **argv)
diff --git a/include/libbb.h b/include/libbb.h
index 5e0b438be..385b30f16 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -165,6 +165,14 @@
 #endif
 
 
+#if defined(__GLIBC__)
+/* glibc uses __errno_location() to get a ptr to errno */
+/* We can just memorize it once - no multithreading in busybox :) */
+extern int *const bb_errno;
+#undef errno
+#define errno (*bb_errno)
+#endif
+
 #if defined(__GLIBC__) && __GLIBC__ < 2
 int vdprintf(int d, const char *format, va_list ap);
 #endif
diff --git a/libbb/error_msg.c b/libbb/error_msg.c
index b2141f3a2..5f53f0311 100644
--- a/libbb/error_msg.c
+++ b/libbb/error_msg.c
@@ -7,10 +7,6 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <stdio.h>
-#include <errno.h>
-#include <string.h>
-#include <stdlib.h>
 #include "libbb.h"
 
 void bb_error_msg(const char *s, ...)
diff --git a/libbb/perror_msg.c b/libbb/perror_msg.c
index 7fb0830be..5145795f5 100644
--- a/libbb/perror_msg.c
+++ b/libbb/perror_msg.c
@@ -7,10 +7,6 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <stdio.h>
-#include <errno.h>
-#include <string.h>
-#include <stdlib.h>
 #include "libbb.h"
 
 void bb_perror_msg(const char *s, ...)
diff --git a/libbb/run_shell.c b/libbb/run_shell.c
index 6be09088d..25d55dd63 100644
--- a/libbb/run_shell.c
+++ b/libbb/run_shell.c
@@ -28,19 +28,12 @@
  * SUCH DAMAGE.
  */
 
-#include <stdio.h>
-#include <errno.h>
-#include <unistd.h>
-#include <string.h>
-#include <stdlib.h>
-#include <syslog.h>
-#include <ctype.h>
 #include "libbb.h"
-#ifdef CONFIG_SELINUX
+#if ENABLE_SELINUX
 #include <selinux/selinux.h>  /* for setexeccon  */
 #endif
 
-#ifdef CONFIG_SELINUX
+#if ENABLE_SELINUX
 static security_context_t current_sid;
 
 void
@@ -90,7 +83,7 @@ void run_shell(const char *shell, int loginshell, const char *command, const cha
 			args[argno++] = *additional_args;
 	}
 	args[argno] = NULL;
-#ifdef CONFIG_SELINUX
+#if ENABLE_SELINUX
 	if (current_sid && !setexeccon(current_sid)) {
 		freecon(current_sid);
 		execve(shell, (char **) args, environ);
diff --git a/libbb/safe_write.c b/libbb/safe_write.c
index c81f1247f..5bbb82e84 100644
--- a/libbb/safe_write.c
+++ b/libbb/safe_write.c
@@ -7,13 +7,8 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <stdio.h>
-#include <errno.h>
-#include <unistd.h>
 #include "libbb.h"
 
-
-
 ssize_t safe_write(int fd, const void *buf, size_t count)
 {
 	ssize_t n;
diff --git a/loginutils/login.c b/loginutils/login.c
index d725466aa..142695008 100644
--- a/loginutils/login.c
+++ b/loginutils/login.c
@@ -12,7 +12,6 @@
 #include <selinux/selinux.h>  /* for is_selinux_enabled()  */
 #include <selinux/get_context_list.h> /* for get_default_context() */
 #include <selinux/flask.h> /* for security class definitions  */
-#include <errno.h>
 #endif
 
 enum {
diff --git a/miscutils/devfsd.c b/miscutils/devfsd.c
index 0b08fb6e5..994b80e76 100644
--- a/miscutils/devfsd.c
+++ b/miscutils/devfsd.c
@@ -56,23 +56,12 @@
 
 #include "libbb.h"
 #include "xregex.h"
-#include <unistd.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdarg.h>
-#include <string.h>
-#include <ctype.h>
-#include <sys/stat.h>
-#include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <dirent.h>
-#include <fcntl.h>
 #include <syslog.h>
-#include <signal.h>
-#include <errno.h>
 #include <sys/sysmacros.h>
 
 
diff --git a/networking/libiproute/libnetlink.c b/networking/libiproute/libnetlink.c
index 5307cec2c..0f6040977 100644
--- a/networking/libiproute/libnetlink.c
+++ b/networking/libiproute/libnetlink.c
@@ -11,16 +11,10 @@
  *
  */
 
-#include "libbb.h"
 #include <sys/socket.h>
-
-#include <errno.h>
-#include <string.h>
-#include <time.h>
-#include <unistd.h>
-
 #include <sys/uio.h>
 
+#include "libbb.h"
 #include "libnetlink.h"
 
 void rtnl_close(struct rtnl_handle *rth)
diff --git a/shell/ash.c b/shell/ash.c
index b1d22e5d2..ea10a65cf 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -127,13 +127,6 @@ static char optlist[NOPTS];
 
 /* ============ Misc data */
 
-#ifdef __GLIBC__
-/* glibc sucks */
-static int *dash_errno;
-#undef errno
-#define errno (*dash_errno)
-#endif
-
 static char nullstr[1];                /* zero length string */
 static const char homestr[] = "HOME";
 static const char snlfmt[] = "%s\n";
@@ -12734,10 +12727,6 @@ int ash_main(int argc, char **argv)
 	struct jmploc jmploc;
 	struct stackmark smark;
 
-#ifdef __GLIBC__
-	dash_errno = __errno_location();
-#endif
-
 #if PROFILE
 	monitor(4, etext, profile_buf, sizeof(profile_buf), 50);
 #endif
diff --git a/util-linux/ipcs.c b/util-linux/ipcs.c
index 393f94832..d7d901921 100644
--- a/util-linux/ipcs.c
+++ b/util-linux/ipcs.c
@@ -8,12 +8,6 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include "libbb.h"
-#include <errno.h>
-#include <time.h>
-#include <pwd.h>
-#include <grp.h>
-
 /* X/OPEN tells us to use <sys/{types,ipc,sem}.h> for semctl() */
 /* X/OPEN tells us to use <sys/{types,ipc,msg}.h> for msgctl() */
 /* X/OPEN tells us to use <sys/{types,ipc,shm}.h> for shmctl() */
@@ -23,7 +17,7 @@
 #include <sys/msg.h>
 #include <sys/shm.h>
 
-
+#include "libbb.h"
 
 /*-------------------------------------------------------------------*/
 /* SHM_DEST and SHM_LOCKED are defined in kernel headers,
diff --git a/util-linux/setarch.c b/util-linux/setarch.c
index f6433d6ba..2fb47f9e8 100644
--- a/util-linux/setarch.c
+++ b/util-linux/setarch.c
@@ -7,11 +7,6 @@
  * Licensed under GPL v2 or later, see file License for details.
 */
 
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <errno.h>
-#include <stdio.h>
 #include <sys/personality.h>
 
 #include "libbb.h"
-- 
2.25.1