[PATCH v2 2/3] util: introduce virBufferEscapeRegex

[Pavel Hrdina <phrdina@xxxxxxxxxx>]

Add a helper to escape all possible meta-characters used for
POSIX extended regular expressions.

Signed-off-by: Pavel Hrdina <phrdina@xxxxxxxxxx>
---

new in v2

 src/libvirt_private.syms |  1 +
 src/util/virbuffer.c     | 19 +++++++++++++++++++
 src/util/virbuffer.h     |  3 +++
 tests/virbuftest.c       | 40 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 63 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index d32c6e7549..bbe283529b 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1312,6 +1312,7 @@ virBufferCurrentContent;
 virBufferError;
 virBufferEscape;
 virBufferEscapeN;
+virBufferEscapeRegex;
 virBufferEscapeSexpr;
 virBufferEscapeShell;
 virBufferEscapeString;
diff --git a/src/util/virbuffer.c b/src/util/virbuffer.c
index 80c8e289d4..f07b119c0f 100644
--- a/src/util/virbuffer.c
+++ b/src/util/virbuffer.c
@@ -556,6 +556,25 @@ virBufferEscapeSexpr(virBufferPtr buf,
 }
 
 /**
+ * virBufferEscapeRegex:
+ * @buf: the buffer to append to
+ * @format: a printf like format string but with only one %s parameter
+ * @str: the string argument which needs to be escaped
+ *
+ * Do a formatted print with a single string to a buffer.  The @str is
+ * escaped to avoid using POSIX extended regular expression meta-characters.
+ * Escaping is not applied to characters specified in @format. Auto
+ * indentation may be applied.
+ */
+void
+virBufferEscapeRegex(virBufferPtr buf,
+                     const char *format,
+                     const char *str)
+{
+    virBufferEscape(buf, '\\', "^$.|?*+()[]{}\\", format, str);
+}
+
+/**
  * virBufferEscape:
  * @buf: the buffer to append to
  * @escape: the escape character to inject
diff --git a/src/util/virbuffer.h b/src/util/virbuffer.h
index d1b64ca3a3..7a7014aa70 100644
--- a/src/util/virbuffer.h
+++ b/src/util/virbuffer.h
@@ -88,6 +88,9 @@ void virBufferEscapeString(virBufferPtr buf, const char *format,
                            const char *str);
 void virBufferEscapeSexpr(virBufferPtr buf, const char *format,
                           const char *str);
+void virBufferEscapeRegex(virBufferPtr buf,
+                          const char *format,
+                          const char *str);
 void virBufferEscapeShell(virBufferPtr buf, const char *str);
 void virBufferURIEncodeString(virBufferPtr buf, const char *str);
 
diff --git a/tests/virbuftest.c b/tests/virbuftest.c
index 5905fee7d4..940e4c1c61 100644
--- a/tests/virbuftest.c
+++ b/tests/virbuftest.c
@@ -405,6 +405,35 @@ testBufEscapeN(const void *opaque)
 
 
 static int
+testBufEscapeRegex(const void *opaque)
+{
+    const struct testBufAddStrData *data = opaque;
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    char *actual;
+    int ret = -1;
+
+    virBufferEscapeRegex(&buf, "%s", data->data);
+
+    if (!(actual = virBufferContentAndReset(&buf))) {
+        VIR_TEST_DEBUG("testBufEscapeN: buf is empty");
+        goto cleanup;
+    }
+
+    if (STRNEQ_NULLABLE(actual, data->expect)) {
+        VIR_TEST_DEBUG("testBufEscapeN: Strings don't match:\n");
+        virTestDifference(stderr, data->expect, actual);
+        goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+    VIR_FREE(actual);
+    return ret;
+}
+
+
+static int
 testBufSetIndent(const void *opaque ATTRIBUTE_UNUSED)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
@@ -492,6 +521,17 @@ mymain(void)
     DO_TEST_ESCAPEN("equal=escape", "equal\\=escape");
     DO_TEST_ESCAPEN("comma,equal=escape", "comma,,equal\\=escape");
 
+#define DO_TEST_ESCAPE_REGEX(data, expect)                                  \
+    do {                                                                    \
+        struct testBufAddStrData info = { data, expect };                   \
+        if (virTestRun("Buf: EscapeRegex", testBufEscapeRegex, &info) < 0)  \
+            ret = -1;                                                       \
+    } while (0)
+
+    DO_TEST_ESCAPE_REGEX("noescape", "noescape");
+    DO_TEST_ESCAPE_REGEX("^$.|?*+()[]{}\\",
+                         "\\^\\$\\.\\|\\?\\*\\+\\(\\)\\[\\]\\{\\}\\\\");
+
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }
 
-- 
2.13.0

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