Try to avoid long unsigned int overflow.

When free size is more than 4G, long unsigned int may enounter overflow

git-svn-id: http://opkg.googlecode.com/svn/trunk@210 e8e0d7a0-c8d9-11dd-a880-a1081c7ac358

2 files changed, 17 insertions, 9 deletions

diff --git a/libopkg/opkg_utils.c b/libopkg/opkg_utils.c
index 6a827e0..fb27b40 100644
--- a/libopkg/opkg_utils.c
+++ b/libopkg/opkg_utils.c
@@ -26,16 +26,24 @@
 
 void print_pkg_status(pkg_t * pkg, FILE * file);
 
-int get_available_blocks(char * filesystem)
+long unsigned int get_available_blocks(char * filesystem)
 {
-     struct statfs sfs;
+    struct statfs sfs;
 
-     if(statfs(filesystem, &sfs)){
-	  fprintf(stderr, "bad statfs\n");
-	  return 0;
-     }
-     /*    fprintf(stderr, "reported fs type %x\n", sfs.f_type); */
-     return ((sfs.f_bavail * sfs.f_bsize) / 1024);
+    if(statfs(filesystem, &sfs)){
+        fprintf(stderr, "bad statfs\n");
+        return 0;
+    }
+    /*    fprintf(stderr, "reported fs type %x\n", sfs.f_type); */
+
+    // Actually ((sfs.f_bavail * sfs.f_bsize) / 1024) 
+    // and here we try to avoid overflow. 
+    if (sfs.f_bsize >= 1024) 
+        return (sfs.f_bavail * (sfs.f_bsize / 1024));
+    else if (sfs.f_bsize > 0)
+        return sfs.f_bavail / (1024 / sfs.f_bsize);
+    fprintf(stderr, "bad statfs f_bsize == 0\n");
+    return 0;
 }
 
 char **read_raw_pkgs_from_file(const char *file_name)
diff --git a/libopkg/opkg_utils.h b/libopkg/opkg_utils.h
index c3e90a9..226c7d1 100644
--- a/libopkg/opkg_utils.h
+++ b/libopkg/opkg_utils.h
@@ -25,7 +25,7 @@ void push_error_list(struct errlist **errors,char * msg);
 void reverse_error_list(struct errlist **errors);
 void free_error_list();
 
-int get_available_blocks(char * filesystem);
+long unsigned int get_available_blocks(char * filesystem);
 char **read_raw_pkgs_from_file(const char *file_name);
 char **read_raw_pkgs_from_stream(FILE *fp);
 char *trim_alloc(char * line);