Commit 9b1b0c574322c0e27ab281a1aeff5499df637048
2020-06-16T10:34:07
Add a snprintf_safe() helper function Returns true on success or false on error _or_ truncation. Since truncation is almost always an error anyway, we might as well make this easier to check. Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
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diff --git a/meson.build b/meson.build
index 05131b6..7041d35 100644
--- a/meson.build
+++ b/meson.build
@@ -421,6 +421,11 @@ test(
env: test_env,
)
test(
+ 'utils',
+ executable('test-utils', 'test/utils.c', dependencies: test_dep),
+ env: test_env,
+)
+test(
'symbols-leak-test',
find_program('test/symbols-leak-test.bash'),
env: test_env,
diff --git a/src/utils.h b/src/utils.h
index 2c35a87..abeaabd 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -26,6 +26,7 @@
#include <errno.h>
#include <inttypes.h>
+#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
@@ -290,4 +291,18 @@ int vasprintf(char **strp, const char *fmt, va_list ap);
# endif /* !HAVE_VASPRINTF */
#endif /* !HAVE_ASPRINTF */
+static inline bool
+ATTR_PRINTF(3, 4)
+snprintf_safe(char *buf, size_t sz, const char *format, ...)
+{
+ va_list ap;
+ int rc;
+
+ va_start(ap, format);
+ rc = vsnprintf(buf, sz, format, ap);
+ va_end(ap);
+
+ return rc >= 0 && (size_t)rc < sz;
+}
+
#endif /* UTILS_H */
diff --git a/test/utils.c b/test/utils.c
new file mode 100644
index 0000000..a385a78
--- /dev/null
+++ b/test/utils.c
@@ -0,0 +1,50 @@
+/*
+ * Copyright © 2019 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "config.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "test.h"
+#include "utils.h"
+
+int
+main(void)
+{
+ char buffer[10];
+
+ assert(!snprintf_safe(buffer, 0, "foo"));
+ assert(!snprintf_safe(buffer, 1, "foo"));
+ assert(!snprintf_safe(buffer, 3, "foo"));
+
+ assert(snprintf_safe(buffer, 10, "foo"));
+ assert(streq(buffer, "foo"));
+
+ assert(!snprintf_safe(buffer, 10, "%s", "1234567890"));
+ assert(snprintf_safe(buffer, 10, "%s", "123456789"));
+
+ return 0;
+}