bzip2/lzma: comprehensible error messages for missing decompressor
H. Peter Anvin [Mon, 12 Jan 2009 22:24:04 +0000 (14:24 -0800)]
Instead of failing to identify a compressed image with a decompressor
that we don't have compiled in, identify it and fail with a
comprehensible panic message.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

init/do_mounts_rd.c
init/initramfs.c
lib/decompress.c

index a015e26..91d0cfc 100644 (file)
@@ -79,9 +79,12 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
        sys_read(fd, buf, size);
 
        *decompressor = decompress_method(buf, size, &compress_name);
-       if (*decompressor) {
+       if (compress_name) {
                printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
                       compress_name, start_block);
+               if (!*decompressor)
+                       printk(KERN_CRIT "RAMDISK: %s decompressor not configured!\n",
+                              compress_name);
                nblocks = 0;
                goto done;
        }
index 76f4a01..9a7290e 100644 (file)
@@ -421,6 +421,8 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
 {
        int written;
        decompress_fn decompress;
+       const char *compress_name;
+       static __initdata char msg_buf[64];
 
        dry_run = check_only;
        header_buf = kmalloc(110, GFP_KERNEL);
@@ -449,10 +451,18 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only)
                        continue;
                }
                this_header = 0;
-               decompress = decompress_method(buf, len, NULL);
+               decompress = decompress_method(buf, len, &compress_name);
                if (decompress)
                        decompress(buf, len, NULL, flush_buffer, NULL,
                                   &my_inptr, error);
+               else if (compress_name) {
+                       if (!message) {
+                               snprintf(msg_buf, sizeof msg_buf,
+                                        "compression method %s not configured",
+                                        compress_name);
+                               message = msg_buf;
+                       }
+               }
                if (state != Reset)
                        error("junk in compressed archive");
                this_header = saved_offset + my_inptr;
index edac55c..961f367 100644 (file)
 #include <linux/types.h>
 #include <linux/string.h>
 
+#ifndef CONFIG_DECOMPRESS_GZIP
+# define gunzip NULL
+#endif
+#ifndef CONFIG_DECOMPRESS_BZIP2
+# define bunzip2 NULL
+#endif
+#ifndef CONFIG_DECOMPRESS_LZMA
+# define unlzma NULL
+#endif
+
 static const struct compress_format {
        unsigned char magic[2];
        const char *name;
        decompress_fn decompressor;
 } compressed_formats[] = {
-#ifdef CONFIG_DECOMPRESS_GZIP
        { {037, 0213}, "gzip", gunzip },
        { {037, 0236}, "gzip", gunzip },
-#endif
-#ifdef CONFIG_DECOMPRESS_BZIP2
        { {0x42, 0x5a}, "bzip2", bunzip2 },
-#endif
-#ifdef CONFIG_DECOMPRESS_LZMA
        { {0x5d, 0x00}, "lzma", unlzma },
-#endif
        { {0, 0}, NULL, NULL }
 };