Merge remote-tracking branch 'remotes/gkurz/tags/9p-next-2020-02-08' into staging

9p patches:
- some more protocol sanity checks
- qtest for readdir
- Christian Schoenebeck now official reviewer

# gpg: Signature made Sat 08 Feb 2020 08:38:10 GMT
# gpg:                using RSA key B4828BAF943140CEF2A3491071D4D5E5822F73D6
# gpg: Good signature from "Greg Kurz <groug@kaod.org>" [full]
# gpg:                 aka "Gregory Kurz <gregory.kurz@free.fr>" [full]
# gpg:                 aka "[jpeg image of size 3330]" [full]
# Primary key fingerprint: B482 8BAF 9431 40CE F2A3  4910 71D4 D5E5 822F 73D6

* remotes/gkurz/tags/9p-next-2020-02-08:
  MAINTAINERS: 9pfs: Add myself as reviewer
  tests/virtio-9p: added readdir test
  hw/9pfs/9p-synth: added directory for readdir test
  9pfs: validate count sent by client with T_readdir
  9pfs: require msize >= 4096
  tests/virtio-9p: add terminating null in v9fs_string_read()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

6 files changed, 211 insertions, 1 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index e72b5e5f69..ce46c0a552 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1578,6 +1578,7 @@ F: include/hw/virtio/
 
 virtio-9p
 M: Greg Kurz <groug@kaod.org>
+R: Christian Schoenebeck <qemu_oss@crudebyte.com>
 S: Odd Fixes
 F: hw/9pfs/
 X: hw/9pfs/xen-9p*
diff --git a/hw/9pfs/9p-synth.c b/hw/9pfs/9p-synth.c
index 54239c9bbf..7eb210ffa8 100644
--- a/hw/9pfs/9p-synth.c
+++ b/hw/9pfs/9p-synth.c
@@ -578,6 +578,25 @@ static int synth_init(FsContext *ctx, Error **errp)
                                        NULL, v9fs_synth_qtest_flush_write,
                                        ctx);
         assert(!ret);
+
+        /* Directory for READDIR test */
+        {
+            V9fsSynthNode *dir = NULL;
+            ret = qemu_v9fs_synth_mkdir(
+                NULL, 0700, QTEST_V9FS_SYNTH_READDIR_DIR, &dir
+            );
+            assert(!ret);
+            for (i = 0; i < QTEST_V9FS_SYNTH_READDIR_NFILES; ++i) {
+                char *name = g_strdup_printf(
+                    QTEST_V9FS_SYNTH_READDIR_FILE, i
+                );
+                ret = qemu_v9fs_synth_add_file(
+                    dir, 0, name, NULL, NULL, ctx
+                );
+                assert(!ret);
+                g_free(name);
+            }
+        }
     }
 
     return 0;
diff --git a/hw/9pfs/9p-synth.h b/hw/9pfs/9p-synth.h
index af7a993a1e..036d7e4a5b 100644
--- a/hw/9pfs/9p-synth.h
+++ b/hw/9pfs/9p-synth.h
@@ -55,6 +55,11 @@ int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode,
 #define QTEST_V9FS_SYNTH_LOPEN_FILE "LOPEN"
 #define QTEST_V9FS_SYNTH_WRITE_FILE "WRITE"
 
+/* for READDIR test */
+#define QTEST_V9FS_SYNTH_READDIR_DIR "ReadDirDir"
+#define QTEST_V9FS_SYNTH_READDIR_FILE "ReadDirFile%d"
+#define QTEST_V9FS_SYNTH_READDIR_NFILES 100
+
 /* Any write to the "FLUSH" file is handled one byte at a time by the
  * backend. If the byte is zero, the backend returns success (ie, 1),
  * otherwise it forces the server to try again forever. Thus allowing
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index b0e445d6bd..9e046f7acb 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1363,8 +1363,20 @@ static void coroutine_fn v9fs_version(void *opaque)
         s->proto_version = V9FS_PROTO_2000L;
     } else {
         v9fs_string_sprintf(&version, "unknown");
+        /* skip min. msize check, reporting invalid version has priority */
+        goto marshal;
     }
 
+    if (s->msize < P9_MIN_MSIZE) {
+        err = -EMSGSIZE;
+        error_report(
+            "9pfs: Client requested msize < minimum msize ("
+            stringify(P9_MIN_MSIZE) ") supported by this server."
+        );
+        goto out;
+    }
+
+marshal:
     err = pdu_marshal(pdu, offset, "ds", s->msize, &version);
     if (err < 0) {
         goto out;
@@ -2422,6 +2434,7 @@ static void coroutine_fn v9fs_readdir(void *opaque)
     int32_t count;
     uint32_t max_count;
     V9fsPDU *pdu = opaque;
+    V9fsState *s = pdu->s;
 
     retval = pdu_unmarshal(pdu, offset, "dqd", &fid,
                            &initial_offset, &max_count);
@@ -2430,6 +2443,14 @@ static void coroutine_fn v9fs_readdir(void *opaque)
     }
     trace_v9fs_readdir(pdu->tag, pdu->id, fid, initial_offset, max_count);
 
+    /* Enough space for a R_readdir header: size[4] Rreaddir tag[2] count[4] */
+    if (max_count > s->msize - 11) {
+        max_count = s->msize - 11;
+        warn_report_once(
+            "9p: bad client: T_readdir with count > msize - 11"
+        );
+    }
+
     fidp = get_fid(pdu, fid);
     if (fidp == NULL) {
         retval = -EINVAL;
diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
index 8d07a0b301..b8f72a3bd9 100644
--- a/hw/9pfs/9p.h
+++ b/hw/9pfs/9p.h
@@ -100,6 +100,17 @@ typedef enum P9ProtoVersion {
     V9FS_PROTO_2000L = 0x02,
 } P9ProtoVersion;
 
+/**
+ * @brief Minimum message size supported by this 9pfs server.
+ *
+ * A client establishes a session by sending a Tversion request along with a
+ * 'msize' parameter which suggests the server a maximum message size ever to be
+ * used for communication (for both requests and replies) between client and
+ * server during that session. If client suggests a 'msize' smaller than this
+ * value then session is denied by server with an error response.
+ */
+#define P9_MIN_MSIZE    4096
+
 #define P9_NOTAG    UINT16_MAX
 #define P9_NOFID    UINT32_MAX
 #define P9_MAXWELEM 16
diff --git a/tests/qtest/virtio-9p-test.c b/tests/qtest/virtio-9p-test.c
index e7b58e3a0c..2167322985 100644
--- a/tests/qtest/virtio-9p-test.c
+++ b/tests/qtest/virtio-9p-test.c
@@ -68,6 +68,11 @@ static void v9fs_memread(P9Req *req, void *addr, size_t len)
     req->r_off += len;
 }
 
+static void v9fs_uint8_read(P9Req *req, uint8_t *val)
+{
+    v9fs_memread(req, val, 1);
+}
+
 static void v9fs_uint16_write(P9Req *req, uint16_t val)
 {
     uint16_t le_val = cpu_to_le16(val);
@@ -101,6 +106,12 @@ static void v9fs_uint32_read(P9Req *req, uint32_t *val)
     le32_to_cpus(val);
 }
 
+static void v9fs_uint64_read(P9Req *req, uint64_t *val)
+{
+    v9fs_memread(req, val, 8);
+    le64_to_cpus(val);
+}
+
 /* len[2] string[len] */
 static uint16_t v9fs_string_size(const char *string)
 {
@@ -130,8 +141,9 @@ static void v9fs_string_read(P9Req *req, uint16_t *len, char **string)
         *len = local_len;
     }
     if (string) {
-        *string = g_malloc(local_len);
+        *string = g_malloc(local_len + 1);
         v9fs_memread(req, *string, local_len);
+        (*string)[local_len] = 0;
     } else {
         v9fs_memskip(req, local_len);
     }
@@ -190,6 +202,7 @@ static const char *rmessage_name(uint8_t id)
         id == P9_RLOPEN ? "RLOPEN" :
         id == P9_RWRITE ? "RWRITE" :
         id == P9_RFLUSH ? "RFLUSH" :
+        id == P9_RREADDIR ? "READDIR" :
         "<unknown>";
 }
 
@@ -347,6 +360,82 @@ static void v9fs_rwalk(P9Req *req, uint16_t *nwqid, v9fs_qid **wqid)
     v9fs_req_free(req);
 }
 
+/* size[4] Treaddir tag[2] fid[4] offset[8] count[4] */
+static P9Req *v9fs_treaddir(QVirtio9P *v9p, uint32_t fid, uint64_t offset,
+                            uint32_t count, uint16_t tag)
+{
+    P9Req *req;
+
+    req = v9fs_req_init(v9p, 4 + 8 + 4, P9_TREADDIR, tag);
+    v9fs_uint32_write(req, fid);
+    v9fs_uint64_write(req, offset);
+    v9fs_uint32_write(req, count);
+    v9fs_req_send(req);
+    return req;
+}
+
+struct V9fsDirent {
+    v9fs_qid qid;
+    uint64_t offset;
+    uint8_t type;
+    char *name;
+    struct V9fsDirent *next;
+};
+
+/* size[4] Rreaddir tag[2] count[4] data[count] */
+static void v9fs_rreaddir(P9Req *req, uint32_t *count, uint32_t *nentries,
+                          struct V9fsDirent **entries)
+{
+    uint32_t local_count;
+    struct V9fsDirent *e = NULL;
+    uint16_t slen;
+    uint32_t n = 0;
+
+    v9fs_req_recv(req, P9_RREADDIR);
+    v9fs_uint32_read(req, &local_count);
+
+    if (count) {
+        *count = local_count;
+    }
+
+    for (int32_t togo = (int32_t)local_count;
+         togo >= 13 + 8 + 1 + 2;
+         togo -= 13 + 8 + 1 + 2 + slen, ++n)
+    {
+        if (!e) {
+            e = g_malloc(sizeof(struct V9fsDirent));
+            if (entries) {
+                *entries = e;
+            }
+        } else {
+            e = e->next = g_malloc(sizeof(struct V9fsDirent));
+        }
+        e->next = NULL;
+        /* qid[13] offset[8] type[1] name[s] */
+        v9fs_memread(req, &e->qid, 13);
+        v9fs_uint64_read(req, &e->offset);
+        v9fs_uint8_read(req, &e->type);
+        v9fs_string_read(req, &slen, &e->name);
+    }
+
+    if (nentries) {
+        *nentries = n;
+    }
+
+    v9fs_req_free(req);
+}
+
+static void v9fs_free_dirents(struct V9fsDirent *e)
+{
+    struct V9fsDirent *next = NULL;
+
+    for (; e; e = next) {
+        next = e->next;
+        g_free(e->name);
+        g_free(e);
+    }
+}
+
 /* size[4] Tlopen tag[2] fid[4] flags[4] */
 static P9Req *v9fs_tlopen(QVirtio9P *v9p, uint32_t fid, uint32_t flags,
                           uint16_t tag)
@@ -479,6 +568,69 @@ static void fs_walk(void *obj, void *data, QGuestAllocator *t_alloc)
     g_free(wqid);
 }
 
+static bool fs_dirents_contain_name(struct V9fsDirent *e, const char* name)
+{
+    for (; e; e = e->next) {
+        if (!strcmp(e->name, name)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static void fs_readdir(void *obj, void *data, QGuestAllocator *t_alloc)
+{
+    QVirtio9P *v9p = obj;
+    alloc = t_alloc;
+    char *const wnames[] = { g_strdup(QTEST_V9FS_SYNTH_READDIR_DIR) };
+    uint16_t nqid;
+    v9fs_qid qid;
+    uint32_t count, nentries;
+    struct V9fsDirent *entries = NULL;
+    P9Req *req;
+
+    fs_attach(v9p, NULL, t_alloc);
+    req = v9fs_twalk(v9p, 0, 1, 1, wnames, 0);
+    v9fs_req_wait_for_reply(req, NULL);
+    v9fs_rwalk(req, &nqid, NULL);
+    g_assert_cmpint(nqid, ==, 1);
+
+    req = v9fs_tlopen(v9p, 1, O_DIRECTORY, 0);
+    v9fs_req_wait_for_reply(req, NULL);
+    v9fs_rlopen(req, &qid, NULL);
+
+    /*
+     * submit count = msize - 11, because 11 is the header size of Rreaddir
+     */
+    req = v9fs_treaddir(v9p, 1, 0, P9_MAX_SIZE - 11, 0);
+    v9fs_req_wait_for_reply(req, NULL);
+    v9fs_rreaddir(req, &count, &nentries, &entries);
+
+    /*
+     * Assuming msize (P9_MAX_SIZE) is large enough so we can retrieve all
+     * dir entries with only one readdir request.
+     */
+    g_assert_cmpint(
+        nentries, ==,
+        QTEST_V9FS_SYNTH_READDIR_NFILES + 2 /* "." and ".." */
+    );
+
+    /*
+     * Check all file names exist in returned entries, ignore their order
+     * though.
+     */
+    g_assert_cmpint(fs_dirents_contain_name(entries, "."), ==, true);
+    g_assert_cmpint(fs_dirents_contain_name(entries, ".."), ==, true);
+    for (int i = 0; i < QTEST_V9FS_SYNTH_READDIR_NFILES; ++i) {
+        char *name = g_strdup_printf(QTEST_V9FS_SYNTH_READDIR_FILE, i);
+        g_assert_cmpint(fs_dirents_contain_name(entries, name), ==, true);
+        g_free(name);
+    }
+
+    v9fs_free_dirents(entries);
+    g_free(wnames[0]);
+}
+
 static void fs_walk_no_slash(void *obj, void *data, QGuestAllocator *t_alloc)
 {
     QVirtio9P *v9p = obj;
@@ -657,6 +809,7 @@ static void register_virtio_9p_test(void)
                  NULL);
     qos_add_test("fs/flush/ignored", "virtio-9p", fs_flush_ignored,
                  NULL);
+    qos_add_test("fs/readdir/basic", "virtio-9p", fs_readdir, NULL);
 }
 
 libqos_init(register_virtio_9p_test);