add some maybe helpful error messages

diff --git a/corsairmi.c b/corsairmi.c
index f45b421..e7a1287 100644 (file)
--- a/corsairmi.c
+++ b/corsairmi.c
@@ -61,6 +61,7 @@
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include <unistd.h>
+#include <errno.h>
 #include <linux/hidraw.h>
 
 static const uint16_t products[] = {
@@ -221,6 +222,7 @@ out:
 
 int main(int argc, char *argv[])
 {
+       int had_eacces = 0;
        char name[63];
        uint32_t v32;
        uint8_t osel;
@@ -240,6 +242,16 @@ int main(int argc, char *argv[])
                        fd = try_open_device(name, 0);
                        if (fd != -1)
                                break;
+                       if (errno == EACCES)
+                               had_eacces = 1;
+               }
+               if (fd == -1) {
+                       fprintf(stderr, "No compatible devices found.\n");
+                       if (had_eacces)
+                               fprintf(stderr, "At least one device "
+                                       "could not be checked because "
+                                       "of lack of permissions for "
+                                       "/dev/hidraw*.\n");
                }
        }