Add debugging code for input buffer underrunsyslinux-2.07-pre6

1 files changed, 32 insertions, 14 deletions

diff --git a/memdisk/unzip.c b/memdisk/unzip.c
index 94f56e43..a3a7f124 100644
--- a/memdisk/unzip.c
+++ b/memdisk/unzip.c
@@ -28,15 +28,18 @@ typedef uint8_t  uch;
 typedef uint16_t ush;
 typedef uint32_t ulg;
 
-#define WSIZE 0x8000		/* Window size must be at least 32k, */
+#define WSIZE 0x8000	        /* Window size must be at least 32k, */
 				/* and a power of two */
 
-static uch *inbuf;	     /* input buffer */
-static uch window[WSIZE];    /* Sliding window buffer */
+static uch *inbuf;		/* input pointer */
+static uch window[WSIZE];	/* sliding output window buffer */
 
-static unsigned insize;      /* valid bytes in inbuf */
-static unsigned inptr;       /* index of next byte to be processed in inbuf */
-static unsigned outcnt;	     /* bytes in output buffer */
+static unsigned insize;		/* total input bytes read */
+static unsigned inbytes;	/* valid bytes in inbuf */
+static unsigned outcnt;		/* bytes in output buffer */
+
+/* This is here to try to debug strange errors seen on some machines. */
+static ulg in_crc;		/* crc of input bytes as read */
 
 /* gzip flag byte */
 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
@@ -47,8 +50,6 @@ static unsigned outcnt;	     /* bytes in output buffer */
 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 
-#define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
-		
 /* Diagnostic functions */
 #ifdef DEBUG
 #  define Assert(cond,msg) {if(!(cond)) error(msg);}
@@ -71,7 +72,23 @@ static void flush_window(void);
 static void error(char *m);
 static void gzip_mark(void **);
 static void gzip_release(void **);
-  
+
+extern ulg crc_32_tab[256];
+
+/* Get byte from input buffer */
+static inline uch get_byte(void)
+{
+  if ( inbytes ) {
+    uch b = *inbuf++;
+    inbytes--;
+    in_crc = crc_32_tab[(in_crc ^ b) & 0xff] ^ (in_crc >> 8);
+    
+    return b;
+  } else {
+    return fill_inbuf();	/* Input buffer underrun */
+  }
+}
+
 static ulg bytes_out = 0;	/* Number of bytes output */
 static uch *output_data;	/* Output data pointer */
 static ulg output_size;		/* Number of output bytes expected */
@@ -123,8 +140,9 @@ static int fill_inbuf(void)
 {
   /* This should never happen.  We have already pointed the algorithm
      to all the data we have. */
-  error("ran out of input data");
-  return 0;
+  printf("failed\nDecompression error: ran out of input data, cksum = %lu %u\n",
+	 in_crc^0xffffffffUL, insize);
+  die();
 }
 
 /* ===========================================================================
@@ -144,7 +162,7 @@ static void flush_window(void)
     out = output_data;
     for (n = 0; n < outcnt; n++) {
 	    ch = *out++ = *in++;
-	    c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
+	    c = crc_32_tab[(c ^ ch) & 0xff] ^ (c >> 8);
     }
     crc = c;
     output_data = out;
@@ -155,7 +173,6 @@ static void flush_window(void)
 static void error(char *x)
 {
   printf("failed\nDecompression error: %s\n", x);
-  puts(x);
   die();
 }
 
@@ -176,8 +193,9 @@ void *unzip(void *indata, unsigned long zbytes, void *target)
   free_mem_end_ptr = free_mem_ptr + 0x10000;
 
   /* Set up input buffer */
+  in_crc = 0xffffffffUL;
   inbuf  = indata;
-  insize = zbytes;
+  insize = inbytes = zbytes;
 
   /* Set up output buffer */
   outcnt = 0;