Add xasprintf to avoid use of undefined pointer values

If asprintf fails for any reason, the contents of the pointer
are undefined. While some platforms set it to NULL, there is no
guarantee that all will.

This change adds a simple wrapper to ensure proper NULL results
on failure.

Signed-off-by: Jon A. Cruz <jonc@osg.samsung.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Added LIBINPUT_PRINTF attribute and the required declaration for it.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

diff --git a/src/libinput-util.h b/src/libinput-util.h
index 732f813008101f4730b471166218f9b85289c54c..910406cfef7597ca4c881fe3c90ef3e91cf1ffc3 100644 (file)
--- a/src/libinput-util.h
+++ b/src/libinput-util.h
@@ -26,6 +26,8 @@
 
 #include <unistd.h>
 #include <math.h>
+#include <stdarg.h>
+#include <stdio.h>
 #include <string.h>
 #include <time.h>
 
@@ -230,6 +232,38 @@ matrix_to_farray6(const struct matrix *m, float out[6])
        out[5] = m->val[1][2];
 }
 
+/**
+ * Simple wrapper for asprintf that ensures the passed in-pointer is set
+ * to NULL upon error.
+ * The standard asprintf() call does not guarantee the passed in pointer
+ * will be NULL'ed upon failure, whereas this wrapper does.
+ *
+ * @param strp pointer to set to newly allocated string.
+ * This pointer should be passed to free() to release when done.
+ * @param fmt the format string to use for printing.
+ * @return The number of bytes printed (excluding the null byte terminator)
+ * upon success or -1 upon failure. In the case of failure the pointer is set
+ * to NULL.
+ */
+static inline int
+xasprintf(char **strp, const char *fmt, ...)
+       LIBINPUT_ATTRIBUTE_PRINTF(2, 3);
+
+static inline int
+xasprintf(char **strp, const char *fmt, ...)
+{
+       int rc = 0;
+       va_list args;
+
+       va_start(args, fmt);
+       rc = vasprintf(strp, fmt, args);
+       va_end(args);
+       if ((rc == -1) && strp)
+               *strp = NULL;
+
+       return rc;
+}
+
 enum ratelimit_state {
        RATELIMIT_EXCEEDED,
        RATELIMIT_THRESHOLD,

diff --git a/test/litest.c b/test/litest.c
index 349eca08411653c01d3b9f80b4d0f124446a166f..30d305669984de41003efbfe3f0d8baaa1df5c44 100644 (file)
--- a/test/litest.c
+++ b/test/litest.c
@@ -876,7 +876,7 @@ litest_init_udev_rules(struct litest_test_device *dev)
                ck_abort_msg("Failed to create udev rules directory (%s)\n",
                             strerror(errno));
 
-       rc = asprintf(&path,
+       rc = xasprintf(&path,
                      "%s/%s%s.rules",
                      UDEV_RULES_D,
                      UDEV_RULE_PREFIX,

diff --git a/tools/libinput-list-devices.c b/tools/libinput-list-devices.c
index 662517312bf980ff770c86f1868f8c390f521b34..68ddb612eedc59ba359ebd132eac90c555f346eb 100644 (file)
--- a/tools/libinput-list-devices.c
+++ b/tools/libinput-list-devices.c
@@ -120,17 +120,17 @@ calibration_default(struct libinput_device *device)
        float calibration[6];
 
        if (!libinput_device_config_calibration_has_matrix(device)) {
-               asprintf(&str, "n/a");
+               xasprintf(&str, "n/a");
                return str;
        }
 
        if (libinput_device_config_calibration_get_default_matrix(device,
                                                  calibration) == 0) {
-               asprintf(&str, "identity matrix");
+               xasprintf(&str, "identity matrix");
                return str;
        }
 
-       asprintf(&str,
+       xasprintf(&str,
                 "%.2f %.2f %.2f %.2f %.2f %.2f",
                 calibration[0],
                 calibration[1],
@@ -150,13 +150,13 @@ scroll_defaults(struct libinput_device *device)
 
        scroll_methods = libinput_device_config_scroll_get_methods(device);
        if (scroll_methods == LIBINPUT_CONFIG_SCROLL_NO_SCROLL) {
-               asprintf(&str, "none");
+               xasprintf(&str, "none");
                return str;
        }
 
        method = libinput_device_config_scroll_get_default_method(device);
 
-       asprintf(&str,
+       xasprintf(&str,
                 "%s%s%s%s%s%s",
                 (method == LIBINPUT_CONFIG_SCROLL_2FG) ? "*" : "",
                 (scroll_methods & LIBINPUT_CONFIG_SCROLL_2FG) ? "two-finger " : "",
@@ -176,12 +176,12 @@ click_defaults(struct libinput_device *device)
 
        click_methods = libinput_device_config_click_get_methods(device);
        if (click_methods == LIBINPUT_CONFIG_CLICK_METHOD_NONE) {
-               asprintf(&str, "none");
+               xasprintf(&str, "none");
                return str;
        }
 
        method = libinput_device_config_click_get_default_method(device);
-       asprintf(&str,
+       xasprintf(&str,
                 "%s%s%s%s",
                 (method == LIBINPUT_CONFIG_CLICK_METHOD_BUTTON_AREAS) ? "*" : "",
                 (click_methods & LIBINPUT_CONFIG_CLICK_METHOD_BUTTON_AREAS) ? "button-areas " : "",