Linux Device Drivers 3 examples

1 files changed, 71 insertions, 0 deletions

diff --git a/misc-progs/mapper.c b/misc-progs/mapper.c
new file mode 100644
index 0000000..ae8db09
--- /dev/null
+++ b/misc-progs/mapper.c
@@ -0,0 +1,71 @@
+/*
+ * mapper.c -- simple file that mmap()s a file region and prints it
+ *
+ * Copyright (C) 1998,2000,2001 Alessandro Rubini
+ * 
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <limits.h>
+
+int main(int argc, char **argv)
+{
+    char *fname;
+    FILE *f;
+    unsigned long offset, len;
+    void *address;
+
+    if (argc !=4
+       || sscanf(argv[2],"%li", &offset) != 1
+       || sscanf(argv[3],"%li", &len) != 1) {
+        fprintf(stderr, "%s: Usage \"%s <file> <offset> <len>\"\n", argv[0],
+                argv[0]);
+        exit(1);
+    }
+    /* the offset might be big (e.g., PCI devices), but conversion trims it */
+    if (offset == INT_MAX) {
+	if (argv[2][1]=='x')
+            sscanf(argv[2]+2, "%lx", &offset);
+        else
+            sscanf(argv[2], "%lu", &offset);
+    }
+
+    fname=argv[1];
+
+    if (!(f=fopen(fname,"r"))) {
+        fprintf(stderr, "%s: %s: %s\n", argv[0], fname, strerror(errno));
+        exit(1);
+    }
+
+    address=mmap(0, len, PROT_READ, MAP_FILE | MAP_PRIVATE, fileno(f), offset);
+
+    if (address == (void *)-1) {
+        fprintf(stderr,"%s: mmap(): %s\n",argv[0],strerror(errno));
+        exit(1);
+    }
+    fclose(f);
+    fprintf(stderr, "mapped \"%s\" from %lu (0x%08lx) to %lu (0x%08lx)\n",
+            fname, offset, offset, offset+len, offset+len);
+
+    fwrite(address, 1, len, stdout);
+    return 0;
+}
+