Input: add compat support for sysfs and /proc capabilities output
authorDmitry Torokhov <dmitry.torokhov@gmail.com>
Mon, 11 Jan 2010 08:05:43 +0000 (00:05 -0800)
committerDmitry Torokhov <dmitry.torokhov@gmail.com>
Tue, 12 Jan 2010 17:30:24 +0000 (09:30 -0800)
Input core displays capabilities bitmasks in form of one or more longs printed
in hex form and separated by spaces. Unfortunately it does not work well
for 32-bit applications running on 64-bit kernels since applications expect
that number is "worth" only 32 bits when kernel advances by 64 bits.

Fix that by ensuring that output produced for compat tasks uses 32-bit units.

Reported-and-tested-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
drivers/input/input.c

index ab060710688fa6064f02dabfca13dc3ef512d43e..30b503b8d67bfb64dd8d84a75adad686b9db403a 100644 (file)
@@ -24,6 +24,7 @@
 #include <linux/mutex.h>
 #include <linux/rcupdate.h>
 #include <linux/smp_lock.h>
+#include "input-compat.h"
 
 MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
 MODULE_DESCRIPTION("Input core");
@@ -764,6 +765,40 @@ static int input_attach_handler(struct input_dev *dev, struct input_handler *han
        return error;
 }
 
+#ifdef CONFIG_COMPAT
+
+static int input_bits_to_string(char *buf, int buf_size,
+                               unsigned long bits, bool skip_empty)
+{
+       int len = 0;
+
+       if (INPUT_COMPAT_TEST) {
+               u32 dword = bits >> 32;
+               if (dword || !skip_empty)
+                       len += snprintf(buf, buf_size, "%x ", dword);
+
+               dword = bits & 0xffffffffUL;
+               if (dword || !skip_empty || len)
+                       len += snprintf(buf + len, max(buf_size - len, 0),
+                                       "%x", dword);
+       } else {
+               if (bits || !skip_empty)
+                       len += snprintf(buf, buf_size, "%lx", bits);
+       }
+
+       return len;
+}
+
+#else /* !CONFIG_COMPAT */
+
+static int input_bits_to_string(char *buf, int buf_size,
+                               unsigned long bits, bool skip_empty)
+{
+       return bits || !skip_empty ?
+               snprintf(buf, buf_size, "%lx", bits) : 0;
+}
+
+#endif
 
 #ifdef CONFIG_PROC_FS
 
@@ -832,14 +867,25 @@ static void input_seq_print_bitmap(struct seq_file *seq, const char *name,
                                   unsigned long *bitmap, int max)
 {
        int i;
-
-       for (i = BITS_TO_LONGS(max) - 1; i > 0; i--)
-               if (bitmap[i])
-                       break;
+       bool skip_empty = true;
+       char buf[18];
 
        seq_printf(seq, "B: %s=", name);
-       for (; i >= 0; i--)
-               seq_printf(seq, "%lx%s", bitmap[i], i > 0 ? " " : "");
+
+       for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
+               if (input_bits_to_string(buf, sizeof(buf),
+                                        bitmap[i], skip_empty)) {
+                       skip_empty = false;
+                       seq_printf(seq, "%s%s", buf, i > 0 ? " " : "");
+               }
+       }
+
+       /*
+        * If no output was produced print a single 0.
+        */
+       if (skip_empty)
+               seq_puts(seq, "0");
+
        seq_putc(seq, '\n');
 }
 
@@ -1128,14 +1174,23 @@ static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
 {
        int i;
        int len = 0;
+       bool skip_empty = true;
+
+       for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
+               len += input_bits_to_string(buf + len, max(buf_size - len, 0),
+                                           bitmap[i], skip_empty);
+               if (len) {
+                       skip_empty = false;
+                       if (i > 0)
+                               len += snprintf(buf + len, max(buf_size - len, 0), " ");
+               }
+       }
 
-       for (i = BITS_TO_LONGS(max) - 1; i > 0; i--)
-               if (bitmap[i])
-                       break;
-
-       for (; i >= 0; i--)
-               len += snprintf(buf + len, max(buf_size - len, 0),
-                               "%lx%s", bitmap[i], i > 0 ? " " : "");
+       /*
+        * If no output was produced print a single 0.
+        */
+       if (len == 0)
+               len = snprintf(buf, buf_size, "%d", 0);
 
        if (add_cr)
                len += snprintf(buf + len, max(buf_size - len, 0), "\n");
@@ -1150,7 +1205,8 @@ static ssize_t input_dev_show_cap_##bm(struct device *dev,                \
 {                                                                      \
        struct input_dev *input_dev = to_input_dev(dev);                \
        int len = input_print_bitmap(buf, PAGE_SIZE,                    \
-                                    input_dev->bm##bit, ev##_MAX, 1);  \
+                                    input_dev->bm##bit, ev##_MAX,      \
+                                    true);                             \
        return min_t(int, len, PAGE_SIZE);                              \
 }                                                                      \
 static DEVICE_ATTR(bm, S_IRUGO, input_dev_show_cap_##bm, NULL)
@@ -1214,7 +1270,7 @@ static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
 
        len = input_print_bitmap(&env->buf[env->buflen - 1],
                                 sizeof(env->buf) - env->buflen,
-                                bitmap, max, 0);
+                                bitmap, max, false);
        if (len >= (sizeof(env->buf) - env->buflen))
                return -ENOMEM;