Try harder to avoid integer overflows in cache file size calculations

on 32-bit platforms.

git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@1794 d4fa192b-c00b-0410-8231-f00ffab90ce4

diff --git a/varnish-cache/bin/varnishd/storage_file.c b/varnish-cache/bin/varnishd/storage_file.c
index 344a5e4ed4936a781b5baab96561caa2a2536ad7..dc1da9cb576f601ddd8889ca4a1971e48db2e6c5 100644 (file)
--- a/varnish-cache/bin/varnishd/storage_file.c
+++ b/varnish-cache/bin/varnishd/storage_file.c
@@ -118,7 +118,7 @@ struct smf_sc {
 static void
 smf_calcsize(struct smf_sc *sc, const char *size, int newfile)
 {
-       uintmax_t l;
+       uintmax_t l, fssize;
        unsigned bs;
        char suff[2];
        int i, explicit;
@@ -127,6 +127,7 @@ smf_calcsize(struct smf_sc *sc, const char *size, int newfile)
 
        AN(sc);
        AZ(fstat(sc->fd, &st));
+       xxxassert(S_ISREG(st.st_mode));
 
 #if defined(HAVE_SYS_MOUNT_H) || defined(HAVE_SYS_VFS_H)
        struct statfs fsst;
@@ -137,8 +138,9 @@ smf_calcsize(struct smf_sc *sc, const char *size, int newfile)
        bs = sc->pagesize;
        if (bs < fsst.f_bsize)
                bs = fsst.f_bsize;
-
-       xxxassert(S_ISREG(st.st_mode));
+       xxxassert(bs % sc->pagesize == 0);
+       xxxassert(bs % fsst.f_bsize == 0);
+       fssize = fsst.f_bsize * fsst.f_bavail;
 
        i = sscanf(size, "%ju%1s", &l, suff); /* can return -1, 0, 1 or 2 */
 
@@ -179,7 +181,7 @@ smf_calcsize(struct smf_sc *sc, const char *size, int newfile)
                                l *= (uintmax_t)(1024UL * 1024UL) *
                                    (uintmax_t)(1024UL * 1024UL);
                        else if (suff[0] == '%') {
-                               l *= fsst.f_bsize * fsst.f_bavail;
+                               l *= fssize;
                                l /= 100;
                        }
                }
@@ -200,14 +202,14 @@ smf_calcsize(struct smf_sc *sc, const char *size, int newfile)
 
                if (l < st.st_size) {
                        AZ(ftruncate(sc->fd, l));
-               } else if (l - st.st_size > fsst.f_bsize * fsst.f_bavail) {
-                       l = ((uintmax_t)fsst.f_bsize * fsst.f_bavail * 80) / 100;
+               } else if (l - st.st_size > fssize) {
+                       l = fssize * 80 / 100;
                        fprintf(stderr, "WARNING: storage file size reduced"
                            " to %ju (80%% of available disk space)\n", l);
                }
        }
 
-       /* round down to of filesystem blocksize or pagesize */
+       /* round down to multiple of filesystem blocksize or pagesize */
        l -= (l % bs);
 
        if (l < MINPAGES * (uintmax_t)sc->pagesize) {