Re: [PATCH] sprintf modifiers in usr/gen_init_cpio.c

[Andrew Morton]

Pragnesh Sampat <pragnesh.sampat@xxxxxxxxxxx> wrote:
>
> The file initramfs_data.cpio is slightly different when generated on
> cygwin, compared to linux, which causes the kernel to panic with the
> message "no cpio magic" (See Documentation/early-userspace/README).
> 
> The problem in cpio generation is due to the difference in sprintf
> modifiers on cygwin.  The code uses "%08ZX" for strlen of a device
> node.  printf man pages discourages "Z" and has 'z' instead.
> Both of these are not available on cygwin sprintf (at least some
> versions of cygwin).  The net result of all of this is that the
> generated file literally contains "ZX" and then the strlen after that
> and messes up that 110 offset etc.  The file is 516 bytes long on the
> system that I tested and on linux it is 512 bytes.
> 
> The fix below just uses "%08X" for that field.  Any basic portable
> modifier should be ok, I think.

ugh, OK.

We'll also need to cast the return value of strlen to the correct type.  On
ppc64 (at least) size_t is 8 bytes and the printf will otherwise grab the wrong
things off the stack.



diff -puN usr/gen_init_cpio.c~cygwin-cpio-fix usr/gen_init_cpio.c
--- 25/usr/gen_init_cpio.c~cygwin-cpio-fix	Tue Feb 17 16:42:36 2004
+++ 25-akpm/usr/gen_init_cpio.c	Tue Feb 17 16:43:49 2004
@@ -56,7 +56,7 @@ static void cpio_trailer(void)
 	const char name[] = "TRAILER!!!";
 
 	sprintf(s, "%s%08X%08X%08lX%08lX%08X%08lX"
-	       "%08X%08X%08X%08X%08X%08ZX%08X",
+	       "%08X%08X%08X%08X%08X%08X%08X",
 		"070701",		/* magic */
 		0,			/* ino */
 		0,			/* mode */
@@ -69,7 +69,7 @@ static void cpio_trailer(void)
 		0,			/* minor */
 		0,			/* rmajor */
 		0,			/* rminor */
-		strlen(name) + 1,	/* namesize */
+		(unsigned)strlen(name) + 1, /* namesize */
 		0);			/* chksum */
 	push_hdr(s);
 	push_rest(name);
@@ -87,7 +87,7 @@ static void cpio_mkdir(const char *name,
 	time_t mtime = time(NULL);
 
 	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
-	       "%08X%08X%08X%08X%08X%08ZX%08X",
+	       "%08X%08X%08X%08X%08X%08X%08X",
 		"070701",		/* magic */
 		ino++,			/* ino */
 		S_IFDIR | mode,		/* mode */
@@ -100,7 +100,7 @@ static void cpio_mkdir(const char *name,
 		1,			/* minor */
 		0,			/* rmajor */
 		0,			/* rminor */
-		strlen(name) + 1,	/* namesize */
+		(unsigned)strlen(name) + 1,/* namesize */
 		0);			/* chksum */
 	push_hdr(s);
 	push_rest(name);
@@ -119,7 +119,7 @@ static void cpio_mknod(const char *name,
 		mode |= S_IFCHR;
 
 	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
-	       "%08X%08X%08X%08X%08X%08ZX%08X",
+	       "%08X%08X%08X%08X%08X%08X%08X",
 		"070701",		/* magic */
 		ino++,			/* ino */
 		mode,			/* mode */
@@ -132,7 +132,7 @@ static void cpio_mknod(const char *name,
 		1,			/* minor */
 		maj,			/* rmajor */
 		min,			/* rminor */
-		strlen(name) + 1,	/* namesize */
+		(unsigned)strlen(name) + 1,/* namesize */
 		0);			/* chksum */
 	push_hdr(s);
 	push_rest(name);
@@ -176,7 +176,7 @@ void cpio_mkfile(const char *filename, c
 	}
 
 	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
-	       "%08X%08X%08X%08X%08X%08ZX%08X",
+	       "%08X%08X%08X%08X%08X%08X%08X",
 		"070701",		/* magic */
 		ino++,			/* ino */
 		mode,			/* mode */
@@ -189,7 +189,7 @@ void cpio_mkfile(const char *filename, c
 		1,			/* minor */
 		0,			/* rmajor */
 		0,			/* rminor */
-		strlen(location) + 1,	/* namesize */
+		(unsigned)strlen(location) + 1,/* namesize */
 		0);			/* chksum */
 	push_hdr(s);
 	push_string(location);

_

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