exports: let kernel decide which flags vary by flavor

Query the kernel to ask which flavors vary by pseudoflavor, and use that
instead of a fixed constant.  To allow the possibility of more flags
varying by pseudoflavor, use the set/clear_flags functions for all
options instead of setting some by hand.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

diff --git a/support/include/exportfs.h b/support/include/exportfs.h
index a5cf482584af668e5f8a847909ec7e827a747705..ce7eac0b7507e7ddab4186b38c7d3dd13479218d 100644 (file)
--- a/support/include/exportfs.h
+++ b/support/include/exportfs.h
@@ -103,6 +103,13 @@ int                                rmtab_read(void);
 
 struct nfskey *                        key_lookup(char *hname);
 
+struct export_features {
+       unsigned int flags;
+       unsigned int secinfo_flags;
+};
+
+struct export_features *get_export_features(void);
+
 /* Record export error.  */
 extern int export_errno;
 

diff --git a/support/include/nfs/export.h b/support/include/nfs/export.h
index f7a99bab964b34ccf779f28b095c4986b303958e..d3e188c4b6a44afa7fc41ed921570e2cd5a8f1b2 100644 (file)
--- a/support/include/nfs/export.h
+++ b/support/include/nfs/export.h
@@ -24,6 +24,16 @@
 #define NFSEXP_FSID            0x2000
 #define        NFSEXP_CROSSMOUNT       0x4000
 #define NFSEXP_NOACL           0x8000 /* reserved for possible ACL related use */
-#define NFSEXP_ALLFLAGS                0xFFFF
+/*
+ * All flags supported by the kernel before addition of the
+ * export_features interface:
+ */
+#define NFSEXP_OLDFLAGS                0x7E3F
+/*
+ * Flags that can vary per flavor, for kernels before addition of the
+ * export_features interface:
+ */
+#define NFSEXP_OLD_SECINFO_FLAGS (NFSEXP_READONLY | NFSEXP_ROOTSQUASH \
+                                       | NFSEXP_ALLSQUASH)
 
 #endif /* _NSF_EXPORT_H */

diff --git a/support/nfs/exports.c b/support/nfs/exports.c
index f1ca6329af5769241f363ed84a366737b9495c06..ef31a8556bd7621b9fb092028b37ac25787ad05b 100644 (file)
--- a/support/nfs/exports.c
+++ b/support/nfs/exports.c
@@ -467,9 +467,6 @@ static void clearflags(int mask, unsigned int active, struct exportent *ep)
        }
 }
 
-/* options that can vary per flavor: */
-#define NFSEXP_SECINFO_FLAGS (NFSEXP_READONLY | NFSEXP_ROOTSQUASH \
-                                       | NFSEXP_ALLSQUASH)
 /*
  * For those flags which are not allowed to vary by pseudoflavor,
  * ensure that the export flags agree with the flags on each
@@ -477,10 +474,12 @@ static void clearflags(int mask, unsigned int active, struct exportent *ep)
  */
 static void fix_pseudoflavor_flags(struct exportent *ep)
 {
+       struct export_features *ef;
        struct sec_entry *p;
 
+       ef = get_export_features();
        for (p = ep->e_secinfo; p->flav; p++)
-               p->flags |= ep->e_flags & ~NFSEXP_SECINFO_FLAGS;
+               p->flags |= ep->e_flags & ~ef->secinfo_flags;
 }
 
 /*
@@ -518,25 +517,25 @@ parseopts(char *cp, struct exportent *ep, int warn, int *had_subtree_opt_ptr)
                else if (strcmp(opt, "rw") == 0)
                        clearflags(NFSEXP_READONLY, active, ep);
                else if (!strcmp(opt, "secure"))
-                       ep->e_flags &= ~NFSEXP_INSECURE_PORT;
+                       clearflags(NFSEXP_INSECURE_PORT, active, ep);
                else if (!strcmp(opt, "insecure"))
-                       ep->e_flags |= NFSEXP_INSECURE_PORT;
+                       setflags(NFSEXP_INSECURE_PORT, active, ep);
                else if (!strcmp(opt, "sync"))
-                       ep->e_flags &= ~NFSEXP_ASYNC;
+                       clearflags(NFSEXP_ASYNC, active, ep);
                else if (!strcmp(opt, "async"))
-                       ep->e_flags |= NFSEXP_ASYNC;
+                       setflags(NFSEXP_ASYNC, active, ep);
                else if (!strcmp(opt, "nohide"))
-                       ep->e_flags |= NFSEXP_NOHIDE;
+                       setflags(NFSEXP_NOHIDE, active, ep);
                else if (!strcmp(opt, "hide"))
-                       ep->e_flags &= ~NFSEXP_NOHIDE;
+                       clearflags(NFSEXP_NOHIDE, active, ep);
                else if (!strcmp(opt, "crossmnt"))
-                       ep->e_flags |= NFSEXP_CROSSMOUNT;
+                       setflags(NFSEXP_CROSSMOUNT, active, ep);
                else if (!strcmp(opt, "nocrossmnt"))
-                       ep->e_flags &= ~NFSEXP_CROSSMOUNT;
+                       clearflags(NFSEXP_CROSSMOUNT, active, ep);
                else if (!strcmp(opt, "wdelay"))
-                       ep->e_flags |= NFSEXP_GATHERED_WRITES;
+                       setflags(NFSEXP_GATHERED_WRITES, active, ep);
                else if (!strcmp(opt, "no_wdelay"))
-                       ep->e_flags &= ~NFSEXP_GATHERED_WRITES;
+                       clearflags(NFSEXP_GATHERED_WRITES, active, ep);
                else if (strcmp(opt, "root_squash") == 0)
                        setflags(NFSEXP_ROOTSQUASH, active, ep);
                else if (!strcmp(opt, "no_root_squash"))
@@ -547,22 +546,22 @@ parseopts(char *cp, struct exportent *ep, int warn, int *had_subtree_opt_ptr)
                        clearflags(NFSEXP_ALLSQUASH, active, ep);
                else if (strcmp(opt, "subtree_check") == 0) {
                        had_subtree_opt = 1;
-                       ep->e_flags &= ~NFSEXP_NOSUBTREECHECK;
+                       clearflags(NFSEXP_NOSUBTREECHECK, active, ep);
                } else if (strcmp(opt, "no_subtree_check") == 0) {
                        had_subtree_opt = 1;
-                       ep->e_flags |= NFSEXP_NOSUBTREECHECK;
+                       setflags(NFSEXP_NOSUBTREECHECK, active, ep);
                } else if (strcmp(opt, "auth_nlm") == 0)
-                       ep->e_flags &= ~NFSEXP_NOAUTHNLM;
+                       clearflags(NFSEXP_NOAUTHNLM, active, ep);
                else if (strcmp(opt, "no_auth_nlm") == 0)
-                       ep->e_flags |= NFSEXP_NOAUTHNLM;
+                       setflags(NFSEXP_NOAUTHNLM, active, ep);
                else if (strcmp(opt, "secure_locks") == 0)
-                       ep->e_flags &= ~NFSEXP_NOAUTHNLM;
+                       clearflags(NFSEXP_NOAUTHNLM, active, ep);
                else if (strcmp(opt, "insecure_locks") == 0)
-                       ep->e_flags |= NFSEXP_NOAUTHNLM;
+                       setflags(NFSEXP_NOAUTHNLM, active, ep);
                else if (strcmp(opt, "acl") == 0)
-                       ep->e_flags &= ~NFSEXP_NOACL;
+                       clearflags(NFSEXP_NOACL, active, ep);
                else if (strcmp(opt, "no_acl") == 0)
-                       ep->e_flags |= NFSEXP_NOACL;
+                       setflags(NFSEXP_NOACL, active, ep);
                else if (strncmp(opt, "anonuid=", 8) == 0) {
                        char *oe;
                        ep->e_anonuid = strtol(opt+8, &oe, 10);
@@ -594,11 +593,11 @@ bad_option:
                        char *oe;
                        if (strcmp(opt+5, "root") == 0) {
                                ep->e_fsid = 0;
-                               ep->e_flags |= NFSEXP_FSID;
+                               setflags(NFSEXP_FSID, active, ep);
                        } else {
                                ep->e_fsid = strtoul(opt+5, &oe, 0);
                                if (opt[5]!='\0' && *oe == '\0') 
-                                       ep->e_flags |= NFSEXP_FSID;
+                                       setflags(NFSEXP_FSID, active, ep);
                                else if (valid_uuid(opt+5))
                                        ep->e_uuid = strdup(opt+5);
                                else {
@@ -639,19 +638,20 @@ bad_option:
                } else {
                        xlog(L_ERROR, "%s:%d: unknown keyword \"%s\"\n",
                                        flname, flline, opt);
-                       ep->e_flags |= NFSEXP_ALLSQUASH | NFSEXP_READONLY;
+                       setflags(NFSEXP_ALLSQUASH | NFSEXP_READONLY, active, ep);
                        goto bad_option;
                }
                free(opt);
                while (isblank(*cp))
                        cp++;
        }
+
        /*
         * Turn on nohide which will allow this export to cross over
         * the 'mount --bind' mount point.
         */
        if (ep->e_fslocdata)
-               ep->e_flags |= NFSEXP_NOHIDE;
+               setflags(NFSEXP_NOHIDE, active, ep);
        fix_pseudoflavor_flags(ep);
        ep->e_squids = squids;
        ep->e_sqgids = sqgids;
@@ -769,3 +769,34 @@ syntaxerr(char *msg)
        xlog(L_ERROR, "%s:%d: syntax error: %s",
                        efname, efp?efp->x_line:0, msg);
 }
+struct export_features *get_export_features(void)
+{
+       static char *path = "/proc/fs/nfsd/export_features";
+       static struct export_features ef;
+       static int cached = 0;
+       char buf[50];
+       int c;
+       int fd;
+
+       if (cached)
+               return &ef;
+
+       ef.flags = NFSEXP_OLDFLAGS;
+       ef.secinfo_flags = NFSEXP_OLD_SECINFO_FLAGS;
+
+       fd = open(path, O_RDONLY);
+       if (fd == -1)
+               goto good;
+       fd = read(fd, buf, 50);
+       if (fd == -1)
+               goto err;
+       c = sscanf(buf, "%x %x", &ef.flags, &ef.secinfo_flags);
+       if (c != 2)
+               goto err;
+good:
+       cached = 1;
+       return &ef;
+err:
+       xlog(L_WARNING, "unexpected error reading %s", path);
+       return &ef;
+}