GCC 7.1 fixes

GCC 7.1 with will warn when we're not checking the snprintf()
return code in cases where the buffer could be truncated. This
patch either checks the snprintf return code (where applicable),
or simply disables the warnings (ztest.c).

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #6253

diff --git a/cmd/ztest/Makefile.am b/cmd/ztest/Makefile.am
index a2f3b5a6b8a2131844206d66cfacec1de5c5d894..5167d0c1d86e7d1dcaa7e5f0d628c2e390aa9a33 100644 (file)
--- a/cmd/ztest/Makefile.am
+++ b/cmd/ztest/Makefile.am
@@ -1,6 +1,8 @@
 include $(top_srcdir)/config/Rules.am
 
-AM_CFLAGS += $(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+# -Wnoformat-truncation to get rid of compiler warning for unchecked
+#  truncating snprintfs on gcc 7.1.1.
+AM_CFLAGS += $(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN) $(NO_FORMAT_TRUNCATION)
 AM_CPPFLAGS += -DDEBUG
 
 DEFAULT_INCLUDES += \

diff --git a/config/user-no-format-truncation.m4 b/config/user-no-format-truncation.m4
new file mode 100644 (file)
index 0000000..4426907
--- /dev/null
+++ b/config/user-no-format-truncation.m4
@@ -0,0 +1,22 @@
+dnl #
+dnl # Check if gcc supports -Wno-format-truncation option.
+dnl #
+AC_DEFUN([ZFS_AC_CONFIG_USER_NO_FORMAT_TRUNCATION], [
+       AC_MSG_CHECKING([for -Wno-format-truncation support])
+
+       saved_flags="$CFLAGS"
+       CFLAGS="$CFLAGS -Wno-format-truncation"
+
+       AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])],
+       [
+               NO_FORMAT_TRUNCATION=-Wno-format-truncation
+               AC_MSG_RESULT([yes])
+       ],
+       [
+               NO_FORMAT_TRUNCATION=
+               AC_MSG_RESULT([no])
+       ])
+
+       CFLAGS="$saved_flags"
+       AC_SUBST([NO_FORMAT_TRUNCATION])
+])

diff --git a/config/user.m4 b/config/user.m4
index 079e2e73b6e5905725dd1f179f05686a35502447..21ff7143a56b0ffa5d821acb94f35691a286233e 100644 (file)
--- a/config/user.m4
+++ b/config/user.m4
@@ -17,6 +17,7 @@ AC_DEFUN([ZFS_AC_CONFIG_USER], [
        ZFS_AC_CONFIG_USER_RUNSTATEDIR
        ZFS_AC_CONFIG_USER_MAKEDEV_IN_SYSMACROS
        ZFS_AC_CONFIG_USER_MAKEDEV_IN_MKDEV
+       ZFS_AC_CONFIG_USER_NO_FORMAT_TRUNCATION
 
        ZFS_AC_TEST_FRAMEWORK
 

diff --git a/lib/libspl/include/assert.h b/lib/libspl/include/assert.h
index bd89ad94fa1c81fbdd408e235a02fb5e1702425b..6237d6bcffd9062a73b4ea88570d1c6f7e6ac62c 100644 (file)
--- a/lib/libspl/include/assert.h
+++ b/lib/libspl/include/assert.h
@@ -40,6 +40,20 @@ libspl_assert(const char *buf, const char *file, const char *func, int line)
        abort();
 }
 
+/* printf version of libspl_assert */
+static inline void
+libspl_assertf(const char *file, const char *func, int line, char *format, ...)
+{
+       va_list args;
+
+       va_start(args, format);
+       vfprintf(stderr, format, args);
+       fprintf(stderr, "\n");
+       fprintf(stderr, "ASSERT at %s:%d:%s()", file, line, func);
+       va_end(args);
+       abort();
+}
+
 #ifdef verify
 #undef verify
 #endif
@@ -55,13 +69,9 @@ libspl_assert(const char *buf, const char *file, const char *func, int line)
 do {                                                                   \
        const TYPE __left = (TYPE)(LEFT);                               \
        const TYPE __right = (TYPE)(RIGHT);                             \
-       if (!(__left OP __right)) {                                     \
-               char *__buf = alloca(256);                              \
-               (void) snprintf(__buf, 256,                             \
-                   "%s %s %s (0x%llx %s 0x%llx)", #LEFT, #OP, #RIGHT,  \
-                   (u_longlong_t)__left, #OP, (u_longlong_t)__right);  \
-               libspl_assert(__buf, __FILE__, __FUNCTION__, __LINE__); \
-       }                                                               \
+       if (!(__left OP __right))                                       \
+               libspl_assertf(__FILE__, __FUNCTION__, __LINE__,        \
+                   "%s %s %s (0x%llx %s 0x%llx)", #LEFT, #OP, #RIGHT); \
 } while (0)
 
 #define        VERIFY3S(x, y, z)       VERIFY3_IMPL(x, y, z, int64_t)

diff --git a/lib/libzfs/libzfs_dataset.c b/lib/libzfs/libzfs_dataset.c
index bc630919a6a6870f5f908b3564dcad7a0087426f..51c168ad79022e508f313c8be19adc917fdf44ea 100644 (file)
--- a/lib/libzfs/libzfs_dataset.c
+++ b/lib/libzfs/libzfs_dataset.c
@@ -3567,8 +3567,9 @@ zfs_check_snap_cb(zfs_handle_t *zhp, void *arg)
        char name[ZFS_MAX_DATASET_NAME_LEN];
        int rv = 0;
 
-       (void) snprintf(name, sizeof (name),
-           "%s@%s", zhp->zfs_name, dd->snapname);
+       if (snprintf(name, sizeof (name), "%s@%s", zhp->zfs_name,
+           dd->snapname) >= sizeof (name))
+               return (EINVAL);
 
        if (lzc_exists(name))
                verify(nvlist_add_boolean(dd->nvl, name) == 0);
@@ -3782,8 +3783,9 @@ zfs_snapshot_cb(zfs_handle_t *zhp, void *arg)
        int rv = 0;
 
        if (zfs_prop_get_int(zhp, ZFS_PROP_INCONSISTENT) == 0) {
-               (void) snprintf(name, sizeof (name),
-                   "%s@%s", zfs_get_name(zhp), sd->sd_snapname);
+               if (snprintf(name, sizeof (name), "%s@%s", zfs_get_name(zhp),
+                   sd->sd_snapname) >= sizeof (name))
+                       return (EINVAL);
 
                fnvlist_add_boolean(sd->sd_nvl, name);
 
@@ -4527,8 +4529,9 @@ zfs_hold_one(zfs_handle_t *zhp, void *arg)
        char name[ZFS_MAX_DATASET_NAME_LEN];
        int rv = 0;
 
-       (void) snprintf(name, sizeof (name),
-           "%s@%s", zhp->zfs_name, ha->snapname);
+       if (snprintf(name, sizeof (name), "%s@%s", zhp->zfs_name,
+           ha->snapname) >= sizeof (name))
+               return (EINVAL);
 
        if (lzc_exists(name))
                fnvlist_add_string(ha->nvl, name, ha->tag);
@@ -4647,8 +4650,11 @@ zfs_release_one(zfs_handle_t *zhp, void *arg)
        int rv = 0;
        nvlist_t *existing_holds;
 
-       (void) snprintf(name, sizeof (name),
-           "%s@%s", zhp->zfs_name, ha->snapname);
+       if (snprintf(name, sizeof (name), "%s@%s", zhp->zfs_name,
+           ha->snapname) >= sizeof (name)) {
+               ha->error = EINVAL;
+               rv = EINVAL;
+       }
 
        if (lzc_get_holds(name, &existing_holds) != 0) {
                ha->error = ENOENT;

diff --git a/lib/libzfs/libzfs_iter.c b/lib/libzfs/libzfs_iter.c
index d78c757a58b718fd7273e15dbbe38102f7f7475b..57ebdd89d1b8e562cc092c85248ef41305ae3a0d 100644 (file)
--- a/lib/libzfs/libzfs_iter.c
+++ b/lib/libzfs/libzfs_iter.c
@@ -204,8 +204,11 @@ zfs_iter_bookmarks(zfs_handle_t *zhp, zfs_iter_f func, void *data)
                bmark_name = nvpair_name(pair);
                bmark_props = fnvpair_value_nvlist(pair);
 
-               (void) snprintf(name, sizeof (name), "%s#%s", zhp->zfs_name,
-                   bmark_name);
+               if (snprintf(name, sizeof (name), "%s#%s", zhp->zfs_name,
+                   bmark_name) >= sizeof (name)) {
+                       err = EINVAL;
+                       goto out;
+               }
 
                nzhp = make_bookmark_handle(zhp, name, bmark_props);
                if (nzhp == NULL)

diff --git a/lib/libzfs/libzfs_sendrecv.c b/lib/libzfs/libzfs_sendrecv.c
index 71ee8faaeaa33d762670c7d69386d3065e80f483..ff909f1e35740674d11e7e3dcd83fff74402872b 100644 (file)
--- a/lib/libzfs/libzfs_sendrecv.c
+++ b/lib/libzfs/libzfs_sendrecv.c
@@ -1867,9 +1867,13 @@ zfs_send(zfs_handle_t *zhp, const char *fromsnap, const char *tosnap,
                            drr_versioninfo, DMU_COMPOUNDSTREAM);
                        DMU_SET_FEATUREFLAGS(drr.drr_u.drr_begin.
                            drr_versioninfo, featureflags);
-                       (void) snprintf(drr.drr_u.drr_begin.drr_toname,
+                       if (snprintf(drr.drr_u.drr_begin.drr_toname,
                            sizeof (drr.drr_u.drr_begin.drr_toname),
-                           "%s@%s", zhp->zfs_name, tosnap);
+                           "%s@%s", zhp->zfs_name, tosnap) >=
+                           sizeof (drr.drr_u.drr_begin.drr_toname)) {
+                               err = EINVAL;
+                               goto stderr_out;
+                       }
                        drr.drr_payloadlen = buflen;
 
                        err = dump_record(&drr, packbuf, buflen, &zc, outfd);

diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index 8cdfe31a2f7f1e087f28cf390a012d46b27a511d..a2f7f045f1f6113df16d8efb3eb81093602e781b 100644 (file)
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -3628,8 +3628,10 @@ zfs_ioc_destroy(zfs_cmd_t *zc)
                         */
                        char namebuf[ZFS_MAX_DATASET_NAME_LEN + 6];
 
-                       (void) snprintf(namebuf, sizeof (namebuf),
-                           "%s/%s", zc->zc_name, recv_clone_name);
+                       if (snprintf(namebuf, sizeof (namebuf), "%s/%s",
+                           zc->zc_name, recv_clone_name) >=
+                           sizeof (namebuf))
+                               return (SET_ERROR(EINVAL));
 
                        /*
                         * Try to remove the hidden child (%recv) and after

diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index 75ed06e03300c23499b4f59abd6518bd99200b67..528acbc227f334220ec1a34bad32cfa9d6b10c91 100644 (file)
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -2154,14 +2154,12 @@ zvol_rename_minors_impl(const char *oldname, const char *newname)
 {
        zvol_state_t *zv, *zv_next;
        int oldnamelen, newnamelen;
-       char *name;
 
        if (zvol_inhibit_dev)
                return;
 
        oldnamelen = strlen(oldname);
        newnamelen = strlen(newname);
-       name = kmem_alloc(MAXNAMELEN, KM_SLEEP);
 
        mutex_enter(&zvol_state_lock);
 
@@ -2181,18 +2179,17 @@ zvol_rename_minors_impl(const char *oldname, const char *newname)
                } else if (strncmp(zv->zv_name, oldname, oldnamelen) == 0 &&
                    (zv->zv_name[oldnamelen] == '/' ||
                    zv->zv_name[oldnamelen] == '@')) {
-                       snprintf(name, MAXNAMELEN, "%s%c%s", newname,
+                       char *name = kmem_asprintf("%s%c%s", newname,
                            zv->zv_name[oldnamelen],
                            zv->zv_name + oldnamelen + 1);
                        zvol_rename_minor(zv, name);
+                       kmem_free(name, strlen(name + 1));
                }
 
                mutex_exit(&zv->zv_state_lock);
        }
 
        mutex_exit(&zvol_state_lock);
-
-       kmem_free(name, MAXNAMELEN);
 }
 
 typedef struct zvol_snapdev_cb_arg {