[PATCH linux-next v2] fix make headers_install when path is too long

[Nicolas Dichtel <nicolas.dichtel@6wind.com>]

If headers_install is executed from a deep/long directory structure, the
shell's maximum argument length can be execeeded, which breaks the operation
with:

| make[2]: execvp: /bin/sh: Argument list too long
| make[2]: ***

Instead of passing each files name with the entire path, I give only the file
name without the source path and give this path as a new argument to
headers_install.pl.

Because there is three possible paths, I have tree input-files list, one per
path.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---

v2: rebase patch on linux-next

 scripts/Makefile.headersinst | 20 ++++++++++++++------
 scripts/headers_install.sh   |  7 +++++--
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/scripts/Makefile.headersinst b/scripts/Makefile.headersinst
index 182084d..8ccf830 100644
--- a/scripts/Makefile.headersinst
+++ b/scripts/Makefile.headersinst
@@ -47,18 +47,24 @@ header-y      := $(filter-out $(generic-y), $(header-y))
 all-files     := $(header-y) $(genhdr-y) $(wrapper-files)
 output-files  := $(addprefix $(installdir)/, $(all-files))
 
-input-files   := $(foreach hdr, $(header-y), \
+input-files1  := $(foreach hdr, $(header-y), \
 		   $(if $(wildcard $(srcdir)/$(hdr)), \
-			$(wildcard $(srcdir)/$(hdr)), \
+			$(wildcard $(srcdir)/$(hdr))) \
+		   )
+input-files1-name := $(notdir $(input-files1))
+input-files2  := $(foreach hdr, $(header-y), \
+		   $(if  $(wildcard $(srcdir)/$(hdr)),, \
 			$(if $(wildcard $(oldsrcdir)/$(hdr)), \
 				$(wildcard $(oldsrcdir)/$(hdr)), \
 				$(error Missing UAPI file $(srcdir)/$(hdr))) \
-		   )) \
-		 $(foreach hdr, $(genhdr-y), \
+		   ))
+input-files2-name := $(notdir $(input-files2))
+input-files3  := $(foreach hdr, $(genhdr-y), \
 		   $(if	$(wildcard $(gendir)/$(hdr)), \
 			$(wildcard $(gendir)/$(hdr)), \
 			$(error Missing generated UAPI file $(gendir)/$(hdr)) \
 		   ))
+input-files3-name := $(notdir $(input-files3))
 
 # Work out what needs to be removed
 oldheaders    := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))
@@ -72,7 +78,9 @@ printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))
 quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
                             file$(if $(word 2, $(all-files)),s))
       cmd_install = \
-        $(CONFIG_SHELL) $< $(installdir) $(input-files); \
+        $(CONFIG_SHELL) $< $(installdir) $(srcdir) $(input-files1-name); \
+        $(CONFIG_SHELL) $< $(installdir) $(oldsrcdir) $(input-files2-name); \
+        $(CONFIG_SHELL) $< $(installdir) $(gendir) $(input-files3-name); \
         for F in $(wrapper-files); do                                   \
                 echo "\#include <asm-generic/$$F>" > $(installdir)/$$F;    \
         done;                                                           \
@@ -98,7 +106,7 @@ __headersinst: $(subdirs) $(install-file)
 	@:
 
 targets += $(install-file)
-$(install-file): scripts/headers_install.sh $(input-files) FORCE
+$(install-file): scripts/headers_install.sh $(input-files1) $(input-files2) $(input-files3) FORCE
 	$(if $(unwanted),$(call cmd,remove),)
 	$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
 	$(call if_changed,install)
diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh
index 643764f..5de5660 100644
--- a/scripts/headers_install.sh
+++ b/scripts/headers_install.sh
@@ -2,7 +2,7 @@
 
 if [ $# -lt 1 ]
 then
-	echo "Usage: headers_install.sh OUTDIR [FILES...]
+	echo "Usage: headers_install.sh OUTDIR SRCDIR [FILES...]
 	echo
 	echo "Prepares kernel header files for use by user space, by removing"
 	echo "all compiler.h definitions and #includes, removing any"
@@ -10,6 +10,7 @@ then
 	echo "asm/inline/volatile keywords."
 	echo
 	echo "OUTDIR: directory to write each userspace header FILE to."
+	echo "SRCDIR: source directory where files are picked."
 	echo "FILES:  list of header files to operate on."
 
 	exit 1
@@ -19,6 +20,8 @@ fi
 
 OUTDIR="$1"
 shift
+SRCDIR="$1"
+shift
 
 # Iterate through files listed on command line
 
@@ -34,7 +37,7 @@ do
 		-e 's/(^|[^a-zA-Z0-9])__packed([^a-zA-Z0-9_]|$)/\1__attribute__((packed))\2/g' \
 		-e 's/(^|[ \t(])(inline|asm|volatile)([ \t(]|$)/\1__\2__\3/g' \
 		-e 's@#(ifndef|define|endif[ \t]*/[*])[ \t]*_UAPI@#\1 @' \
-		"$i" > "$OUTDIR/$FILE.sed" || exit 1
+		"$SRCDIR/$i" > "$OUTDIR/$FILE.sed" || exit 1
 	scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ "$OUTDIR/$FILE.sed" \
 		> "$OUTDIR/$FILE"
 	[ $? -gt 1 ] && exit 1
-- 
1.8.2.1