[Qemu-devel] [PATCH v2 1/4] qtest: allow arbitrarily long sends

[John Snow]

qtest currently has a static buffer of size 1024 that if we
overflow, ignores the additional data silently which leads
to hangs or stream failures.

Use glib's string facilities to allow arbitrarily long data,
but split this off into a new function, qtest_sendf.

Static data can still be sent using qtest_send, which avoids
the malloc/copy overflow.

Signed-off-by: John Snow <js...@redhat.com>
---
 qtest.c | 46 ++++++++++++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 18 deletions(-)

diff --git a/qtest.c b/qtest.c
index 8d1e66c..f635a48 100644
--- a/qtest.c
+++ b/qtest.c
@@ -182,21 +182,29 @@ static void qtest_send_prefix(CharDriverState *chr)
             (long) tv.tv_sec, (long) tv.tv_usec);
 }
 
-static void GCC_FMT_ATTR(2, 3) qtest_send(CharDriverState *chr,
-                                          const char *fmt, ...)
+static void do_qtest_send(CharDriverState *chr, const char *str, size_t len)
+{
+    qemu_chr_fe_write_all(chr, (uint8_t *)str, len);
+    if (qtest_log_fp && qtest_opened) {
+        fprintf(qtest_log_fp, "%s", str);
+    }
+}
+
+static void qtest_send(CharDriverState *chr, const char *str)
+{
+    do_qtest_send(chr, str, strlen(str));
+}
+
+static void GCC_FMT_ATTR(2, 3) qtest_sendf(CharDriverState *chr,
+                                           const char *fmt, ...)
 {
     va_list ap;
-    char buffer[1024];
-    size_t len;
+    gchar *buffer;
 
     va_start(ap, fmt);
-    len = vsnprintf(buffer, sizeof(buffer), fmt, ap);
+    buffer = g_strdup_vprintf(fmt, ap);
+    qtest_send(chr, buffer);
     va_end(ap);
-
-    qemu_chr_fe_write_all(chr, (uint8_t *)buffer, len);
-    if (qtest_log_fp && qtest_opened) {
-        fprintf(qtest_log_fp, "%s", buffer);
-    }
 }
 
 static void qtest_irq_handler(void *opaque, int n, int level)
@@ -208,8 +216,8 @@ static void qtest_irq_handler(void *opaque, int n, int 
level)
         CharDriverState *chr = qtest_chr;
         irq_levels[n] = level;
         qtest_send_prefix(chr);
-        qtest_send(chr, "IRQ %s %d\n",
-                   level ? "raise" : "lower", n);
+        qtest_sendf(chr, "IRQ %s %d\n",
+                    level ? "raise" : "lower", n);
     }
 }
 
@@ -318,7 +326,7 @@ static void qtest_process_command(CharDriverState *chr, 
gchar **words)
             value = cpu_inl(addr);
         }
         qtest_send_prefix(chr);
-        qtest_send(chr, "OK 0x%04x\n", value);
+        qtest_sendf(chr, "OK 0x%04x\n", value);
     } else if (strcmp(words[0], "writeb") == 0 ||
                strcmp(words[0], "writew") == 0 ||
                strcmp(words[0], "writel") == 0 ||
@@ -375,7 +383,7 @@ static void qtest_process_command(CharDriverState *chr, 
gchar **words)
             tswap64s(&value);
         }
         qtest_send_prefix(chr);
-        qtest_send(chr, "OK 0x%016" PRIx64 "\n", value);
+        qtest_sendf(chr, "OK 0x%016" PRIx64 "\n", value);
     } else if (strcmp(words[0], "read") == 0) {
         uint64_t addr, len, i;
         uint8_t *data;
@@ -390,7 +398,7 @@ static void qtest_process_command(CharDriverState *chr, 
gchar **words)
         qtest_send_prefix(chr);
         qtest_send(chr, "OK 0x");
         for (i = 0; i < len; i++) {
-            qtest_send(chr, "%02x", data[i]);
+            qtest_sendf(chr, "%02x", data[i]);
         }
         qtest_send(chr, "\n");
 
@@ -434,7 +442,8 @@ static void qtest_process_command(CharDriverState *chr, 
gchar **words)
         }
         qtest_clock_warp(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns);
         qtest_send_prefix(chr);
-        qtest_send(chr, "OK %"PRIi64"\n", 
(int64_t)qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
+        qtest_sendf(chr, "OK %"PRIi64"\n",
+                    (int64_t)qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
     } else if (qtest_enabled() && strcmp(words[0], "clock_set") == 0) {
         int64_t ns;
 
@@ -442,10 +451,11 @@ static void qtest_process_command(CharDriverState *chr, 
gchar **words)
         ns = strtoll(words[1], NULL, 0);
         qtest_clock_warp(ns);
         qtest_send_prefix(chr);
-        qtest_send(chr, "OK %"PRIi64"\n", 
(int64_t)qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
+        qtest_sendf(chr, "OK %"PRIi64"\n",
+                    (int64_t)qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
     } else {
         qtest_send_prefix(chr);
-        qtest_send(chr, "FAIL Unknown command `%s'\n", words[0]);
+        qtest_sendf(chr, "FAIL Unknown command `%s'\n", words[0]);
     }
 }
 
-- 
2.1.0