binfmt_flat: allow compressed flat binary format to work on MMU systems

Let's take the simple and obvious approach by decompressing the binary
into a kernel buffer and then copying it to user space.  Those who are
looking for top performance on an MMU system are unlikely to choose this
executable format anyway.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 506139b..9b2917a 100644 (file)
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -34,6 +34,7 @@
 #include <linux/init.h>
 #include <linux/flat.h>
 #include <linux/uaccess.h>
+#include <linux/vmalloc.h>
 
 #include <asm/byteorder.h>
 #include <asm/unaligned.h>
@@ -628,6 +629,7 @@ static int load_flat_file(struct linux_binprm *bprm,
                 * load it all in and treat it like a RAM load from now on
                 */
                if (flags & FLAT_FLAG_GZIP) {
+#ifndef CONFIG_MMU
                        result = decompress_exec(bprm, sizeof(struct flat_hdr),
                                         (((char *)textpos) + sizeof(struct flat_hdr)),
                                         (text_len + full_data
@@ -635,13 +637,51 @@ static int load_flat_file(struct linux_binprm *bprm,
                                         0);
                        memmove((void *) datapos, (void *) realdatastart,
                                        full_data);
+#else
+                       /*
+                        * This is used on MMU systems mainly for testing.
+                        * Let's use a kernel buffer to simplify things.
+                        */
+                       long unz_text_len = text_len - sizeof(struct flat_hdr);
+                       long unz_len = unz_text_len + full_data;
+                       char *unz_data = vmalloc(unz_len);
+                       if (!unz_data) {
+                               result = -ENOMEM;
+                       } else {
+                               result = decompress_exec(bprm, sizeof(struct flat_hdr),
+                                                        unz_data, unz_len, 0);
+                               if (result == 0 &&
+                                   (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
+                                                 unz_data, unz_text_len) ||
+                                    copy_to_user((void __user *)datapos,
+                                                 unz_data + unz_text_len, full_data)))
+                                       result = -EFAULT;
+                               vfree(unz_data);
+                       }
+#endif
                } else if (flags & FLAT_FLAG_GZDATA) {
                        result = read_code(bprm->file, textpos, 0, text_len);
-                       if (!IS_ERR_VALUE(result))
+                       if (!IS_ERR_VALUE(result)) {
+#ifndef CONFIG_MMU
                                result = decompress_exec(bprm, text_len, (char *) datapos,
                                                 full_data, 0);
-               } else
+#else
+                               char *unz_data = vmalloc(full_data);
+                               if (!unz_data) {
+                                       result = -ENOMEM;
+                               } else {
+                                       result = decompress_exec(bprm, text_len,
+                                                      unz_data, full_data, 0);
+                                       if (result == 0 &&
+                                           copy_to_user((void __user *)datapos,
+                                                        unz_data, full_data))
+                                               result = -EFAULT;
+                                       vfree(unz_data);
+                               }
 #endif
+                       }
+               } else
+#endif /* CONFIG_BINFMT_ZFLAT */
                {
                        result = read_code(bprm->file, textpos, 0, text_len);
                        if (!IS_ERR_VALUE(result))