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-rw-r--r--tdekbdledsync/getfd.c84
1 files changed, 84 insertions, 0 deletions
diff --git a/tdekbdledsync/getfd.c b/tdekbdledsync/getfd.c
new file mode 100644
index 000000000..589d8dd31
--- /dev/null
+++ b/tdekbdledsync/getfd.c
@@ -0,0 +1,84 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <linux/kd.h>
+#include "getfd.h"
+
+/*
+ * getfd.c
+ *
+ * Get an fd for use with kbd/console ioctls.
+ * We try several things because opening /dev/console will fail
+ * if someone else used X (which does a chown on /dev/console).
+ */
+
+static int
+is_a_console(int fd) {
+ char arg;
+
+ arg = 0;
+ return (ioctl(fd, KDGKBTYPE, &arg) == 0
+ && ((arg == KB_101) || (arg == KB_84)));
+}
+
+static int
+open_a_console(const char *fnam) {
+ int fd;
+
+ /*
+ * For ioctl purposes we only need some fd and permissions
+ * do not matter. But setfont:activatemap() does a write.
+ */
+ fd = open(fnam, O_RDWR);
+ if (fd < 0 && errno == EACCES)
+ fd = open(fnam, O_WRONLY);
+ if (fd < 0 && errno == EACCES)
+ fd = open(fnam, O_RDONLY);
+ if (fd < 0)
+ return -1;
+ if (!is_a_console(fd)) {
+ close(fd);
+ return -1;
+ }
+ return fd;
+}
+
+int getfd(const char *fnam) {
+ int fd;
+
+ if (fnam) {
+ fd = open_a_console(fnam);
+ if (fd >= 0)
+ return fd;
+ fprintf(stderr,
+ ("Couldnt open %s\n"), fnam);
+ exit(1);
+ }
+
+ fd = open_a_console("/dev/tty");
+ if (fd >= 0)
+ return fd;
+
+ fd = open_a_console("/dev/tty0");
+ if (fd >= 0)
+ return fd;
+
+ fd = open_a_console("/dev/vc/0");
+ if (fd >= 0)
+ return fd;
+
+ fd = open_a_console("/dev/console");
+ if (fd >= 0)
+ return fd;
+
+ for (fd = 0; fd < 3; fd++)
+ if (is_a_console(fd))
+ return fd;
+
+ fprintf(stderr,
+ ("Couldnt get a file descriptor referring to the console\n"));
+ exit(1); /* total failure */
+}