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Make external toolchain relocatable

The external toolchain wrapper sets sysroot etc. to an absolute path.
By changing this to a relative path, it is possible to move the host
directory to a different location and still have a working build
system.

This only works for a downloaded external toolchain.  For a pre-installed
external toolchain, it is possible to move the host directory to a
different location, but not the external toolchain directory (it does work
if the external toolchain directory lies within the host directory).  For
an internal or crosstool-ng toolchain, there is no wrapper so updating the
sysroot path should be done in a different way.

See http://lists.busybox.net/pipermail/buildroot/2012-February/050371.html
for information about others things to do to make the host directory
relocatable.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Acked-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
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1 parent 1b2ab4a commit befb9a3ee0c5994162f527d8ef763d57d68ec48e @arnout arnout committed with jacmet Jul 15, 2012
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@@ -65,7 +65,8 @@ ifeq ($(BR2_xtensa),y)
TARGET_ABI += -mlongcalls
endif
-STAGING_DIR=$(HOST_DIR)/usr/$(GNU_TARGET_NAME)/sysroot
+STAGING_SUBDIR = usr/$(GNU_TARGET_NAME)/sysroot
+STAGING_DIR = $(HOST_DIR)/$(STAGING_SUBDIR)
TARGET_OPTIMIZATION:=$(call qstrip,$(BR2_TARGET_OPTIMIZATION))
@@ -121,9 +121,17 @@ endif
TOOLCHAIN_EXTERNAL_CROSS=$(TOOLCHAIN_EXTERNAL_BIN)/$(TOOLCHAIN_EXTERNAL_PREFIX)-
TOOLCHAIN_EXTERNAL_CC=$(TOOLCHAIN_EXTERNAL_CROSS)gcc
TOOLCHAIN_EXTERNAL_CXX=$(TOOLCHAIN_EXTERNAL_CROSS)g++
-TOOLCHAIN_EXTERNAL_WRAPPER_ARGS = \
- -DBR_CROSS_PATH='"$(TOOLCHAIN_EXTERNAL_BIN)/"' \
- -DBR_SYSROOT='"$(STAGING_DIR)"'
+TOOLCHAIN_EXTERNAL_WRAPPER_ARGS = -DBR_SYSROOT='"$(STAGING_SUBDIR)"'
+
+ifeq ($(filter $(HOST_DIR)/%,$(TOOLCHAIN_EXTERNAL_BIN)),)
+# TOOLCHAIN_EXTERNAL_BIN points outside HOST_DIR => absolute path
+TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += \
+ -DBR_CROSS_PATH_ABS='"$(TOOLCHAIN_EXTERNAL_BIN)"'
+else
+# TOOLCHAIN_EXTERNAL_BIN points inside HOST_DIR => relative path
+TOOLCHAIN_EXTERNAL_WRAPPER_ARGS += \
+ -DBR_CROSS_PATH_REL='"$(TOOLCHAIN_EXTERNAL_BIN:$(HOST_DIR)/%=%)"'
+endif
CC_TARGET_TUNE_:=$(call qstrip,$(BR2_GCC_TARGET_TUNE))
CC_TARGET_CPU_:=$(call qstrip,$(BR2_GCC_TARGET_CPU))
@@ -456,7 +464,7 @@ $(HOST_DIR)/usr/bin/ext-toolchain-wrapper: $(STAMP_DIR)/ext-toolchain-installed
ln -sf $(@F) $$base; \
;; \
*) \
- ln -sf $$i .; \
+ ln -sf $$(echo $$i | sed 's%^$(HOST_DIR)%../..%') .; \
;; \
esac; \
done ;
@@ -2,9 +2,12 @@
* Buildroot wrapper for external toolchains. This simply executes the real
* toolchain with a number of arguments (sysroot/arch/..) hardcoded,
* to ensure the external toolchain uses the correct configuration.
+ * The hardcoded path arguments are defined relative to the actual location
+ * of the binary.
*
* (C) 2011 Peter Korsgaard <jacmet@sunsite.dk>
* (C) 2011 Daniel Nyström <daniel.nystrom@timeterminal.se>
+ * (C) 2012 Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
@@ -17,11 +20,12 @@
#include <unistd.h>
#include <stdlib.h>
-static char path[PATH_MAX] = BR_CROSS_PATH;
+static char path[PATH_MAX];
+static char sysroot[PATH_MAX];
static char *predef_args[] = {
path,
- "--sysroot", BR_SYSROOT,
+ "--sysroot", sysroot,
#ifdef BR_ARCH
"-march=" BR_ARCH,
#endif /* BR_ARCH */
@@ -48,22 +52,50 @@ static char *predef_args[] = {
#endif
};
-static const char *get_basename(const char *name)
-{
- const char *base;
-
- base = strrchr(name, '/');
- if (base)
- base++;
- else
- base = name;
-
- return base;
-}
-
int main(int argc, char **argv)
{
char **args, **cur;
+ char *relbasedir, *absbasedir;
+ char *progpath = argv[0];
+ char *basename;
+ int ret;
+
+ /* Calculate the relative paths */
+ basename = strrchr(progpath, '/');
+ if (basename) {
+ *basename = '\0';
+ basename++;
+ relbasedir = malloc(strlen(progpath) + 7);
+ if (relbasedir == NULL) {
+ perror(__FILE__ ": malloc");
+ return 2;
+ }
+ sprintf(relbasedir, "%s/../..", argv[0]);
+ absbasedir = realpath(relbasedir, NULL);
+ } else {
+ basename = progpath;
+ absbasedir = realpath("../..", NULL);
+ }
+ if (absbasedir == NULL) {
+ perror(__FILE__ ": realpath");
+ return 2;
+ }
+
+ /* Fill in the relative paths */
+#ifdef BR_CROSS_PATH_REL
+ ret = snprintf(path, sizeof(path), "%s/" BR_CROSS_PATH_REL "/%s", absbasedir, basename);
+#else /* BR_CROSS_PATH_ABS */
+ ret = snprintf(path, sizeof(path), BR_CROSS_PATH_ABS "/%s", basename);
+#endif
+ if (ret >= sizeof(path)) {
+ perror(__FILE__ ": overflow");
+ return 3;
+ }
+ ret = snprintf(sysroot, sizeof(sysroot), "%s/" BR_SYSROOT, absbasedir);
+ if (ret >= sizeof(sysroot)) {
+ perror(__FILE__ ": overflow");
+ return 3;
+ }
cur = args = malloc(sizeof(predef_args) + (sizeof(char *) * argc));
if (args == NULL) {
@@ -82,8 +114,6 @@ int main(int argc, char **argv)
/* finish with NULL termination */
*cur = NULL;
- strcat(path, get_basename(argv[0]));
-
if (execv(path, args))
perror(path);

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