klibc - Jan 2019 - [PATCH] fix build failure when CONFIG_KLIBC_ZLIB is not set

When CONFIG_KLIBC_ZLIB is not set, related functions
shall not be called otherwise build failure is encountered:

  KLIBCLD usr/kinit/static/kinit
usr/kinit/ramdisk_load.o: In function `load_ramdisk_compressed':
/root/ldb_base/ofl/packages/klibc/usr/kinit/ramdisk_load.c:68: undefined
reference to `inflateInit2_'
/root/ldb_base/ofl/packages/klibc/usr/kinit/ramdisk_load.c:116: undefined
reference to `inflate'
/root/ldb_base/ofl/packages/klibc/usr/kinit/ramdisk_load.c:128: undefined
reference to `inflateEnd'
/root/ldb_base/ofl/packages/klibc/usr/kinit/ramdisk_load.c:132: undefined
reference to `inflateEnd'
make[2]: *** [usr/kinit/shared/kinit] Error 1

Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
---
 usr/kinit/initrd.c       | 6 ++++++
 usr/kinit/ramdisk_load.c | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/usr/kinit/initrd.c b/usr/kinit/initrd.c
index 7eece2ce..a8385a98 100644
--- a/usr/kinit/initrd.c
+++ b/usr/kinit/initrd.c
@@ -54,11 +54,14 @@ static int rd_copy_image(const char *path)
 {
 	int ffd = open(path, O_RDONLY);
 	int rv = -1;
+#ifdef CONFIG_KLIBC_ZLIB
 	unsigned char gzip_magic[2];
+#endif
 
 	if (ffd < 0)
 		goto barf;
 
+#ifdef CONFIG_KLIBC_ZLIB
 	if (xpread(ffd, gzip_magic, 2, 0) == 2 &&
 	    gzip_magic[0] == 037 && gzip_magic[1] == 0213) {
 		FILE *wfd = fopen("/dev/ram0", "w");
@@ -67,6 +70,9 @@ static int rd_copy_image(const char *path)
 		rv = load_ramdisk_compressed(path, wfd, 0);
 		fclose(wfd);
 	} else {
+#else
+	{
+#endif
 		int dfd = open("/dev/ram0", O_WRONLY);
 		if (dfd < 0)
 			goto barf;
diff --git a/usr/kinit/ramdisk_load.c b/usr/kinit/ramdisk_load.c
index 2b3503ad..c30f61c2 100644
--- a/usr/kinit/ramdisk_load.c
+++ b/usr/kinit/ramdisk_load.c
@@ -13,7 +13,9 @@
 #include "kinit.h"
 #include "do_mounts.h"
 #include "fstype.h"
+#ifdef CONFIG_KLIBC_ZLIB
 #include "zlib.h"
+#endif
 
 #define BUF_SZ		65536
 
@@ -46,6 +48,7 @@ static int change_disk(const char *devpath, int rfd, int disk)
 	return open(devpath, O_RDONLY);
 }
 
+#ifdef CONFIG_KLIBC_ZLIB
 /* Also used in initrd.c */
 int load_ramdisk_compressed(const char *devpath, FILE * wfd,
 			    off_t ramdisk_start)
@@ -133,6 +136,7 @@ err2:
 err1:
 	return -1;
 }
+#endif
 
 static int
 load_ramdisk_raw(const char *devpath, FILE * wfd, off_t ramdisk_start,
@@ -253,9 +257,11 @@ int ramdisk_load(int argc, char *argv[])
 
 	close(rfd);
 
+#ifdef CONFIG_KLIBC_ZLIB
 	if (is_gzip)
 		err = load_ramdisk_compressed("/dev/rddev", wfd, ramdisk_start);
 	else
+#endif
 		err = load_ramdisk_raw("/dev/rddev", wfd,
 				       ramdisk_start, fssize);
 
-- 
2.13.3

Hi Christophe.

Thanks for the patch.

On Tue, Jan 22, 2019 at 04:42:47PM +0000, Christophe Leroy
wrote:
> When CONFIG_KLIBC_ZLIB is not set, related functions
> shall not be called otherwise build failure is encountered:
> 
>   KLIBCLD usr/kinit/static/kinit
> usr/kinit/ramdisk_load.o: In function `load_ramdisk_compressed':
> /root/ldb_base/ofl/packages/klibc/usr/kinit/ramdisk_load.c:68: undefined
reference to `inflateInit2_'
> /root/ldb_base/ofl/packages/klibc/usr/kinit/ramdisk_load.c:116: undefined
reference to `inflate'
> /root/ldb_base/ofl/packages/klibc/usr/kinit/ramdisk_load.c:128: undefined
reference to `inflateEnd'
> /root/ldb_base/ofl/packages/klibc/usr/kinit/ramdisk_load.c:132: undefined
reference to `inflateEnd'
> make[2]: *** [usr/kinit/shared/kinit] Error 1
> 
> Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
> ---
>  usr/kinit/initrd.c       | 6 ++++++
>  usr/kinit/ramdisk_load.c | 6 ++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/usr/kinit/initrd.c b/usr/kinit/initrd.c
> index 7eece2ce..a8385a98 100644
> --- a/usr/kinit/initrd.c
> +++ b/usr/kinit/initrd.c
> @@ -54,11 +54,14 @@ static int rd_copy_image(const char *path)
>  {
>  	int ffd = open(path, O_RDONLY);
>  	int rv = -1;
> +#ifdef CONFIG_KLIBC_ZLIB
>  	unsigned char gzip_magic[2];
> +#endif
>  
>  	if (ffd < 0)
>  		goto barf;
>  
> +#ifdef CONFIG_KLIBC_ZLIB
>  	if (xpread(ffd, gzip_magic, 2, 0) == 2 &&
>  	    gzip_magic[0] == 037 && gzip_magic[1] == 0213) {
>  		FILE *wfd = fopen("/dev/ram0", "w");
> @@ -67,6 +70,9 @@ static int rd_copy_image(const char *path)
>  		rv = load_ramdisk_compressed(path, wfd, 0);
>  		fclose(wfd);
>  	} else {
> +#else
> +	{
> +#endif
This is a confusing way to implement conditional compilation.

Please try something else that is simpler.
MAbe move the relevant code parts to a small helper function,
and then based on the configuration select one or the other helper
function.

This makes the main code body much easier to follow.

Same comment for the next file you patched.

If it is hard to follow the diff (I could not do so in this case),
then you probarly have to do it in a different way.

If you go for moving to a helper function that could be the first
patch, and the second introduced conditional compilation.

I hope this make sense and is useful for you.

	Sam