- c is better than lua

Changed files:
    update-fstab.c -> 1.1

diff --git a/update-fstab.c b/update-fstab.c
new file mode 100644 (file)
index 0000000..34fb649
--- /dev/null
+++ b/update-fstab.c
@@ -0,0 +1,85 @@
+/*
+ * $Id$
+ * adds devmode and devgid to usbfs in fstab
+ *
+ */
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+
+void eputs(const char *msg)
+{
+       write(2, msg, strlen(msg));
+}
+
+int main()
+{
+       char *name = "/etc/fstab";
+       char *backup_name = "/etc/fstab.bak";
+       char *add = ",devmode=0664,devgid=78";
+       
+       char *old;
+       int i, fd;
+       int old_sz;
+       struct stat st;
+
+       eputs("Updating /etc/fstab...");
+       fd = open(name, O_RDONLY);
+       if (fd < 0) {
+               eputs("\nError: can't open file\n");
+               return 1;
+       }
+       fstat(fd, &st);
+       old = (char *) malloc(st.st_size);
+       read(fd, old, st.st_size);
+       close(fd);
+       old_sz = st.st_size;
+       
+       fd = open(backup_name, O_WRONLY|O_CREAT|O_TRUNC, 0600);
+       if (fd < 0) {
+               eputs("\nError: can't make backup\n");
+               return 2;
+       }
+       write(fd, old, old_sz);
+       close(fd);
+       
+       // find usbfs
+       for (i = 0; i < old_sz; i++) {
+               if ( old[i] == 'u' && old[i+1] == 's' && old[i+2] == 'b'
+                               && old[i+3] == 'f' && old[i+4] == 's')
+                       break;
+       }
+       // find defau(lts)
+       for (;i < old_sz; i++) {
+               if ( old[i] == 'd' && old[i+1] == 'e' && old[i+2] == 'f' && old[i+3] == 'a' && old[i+4] == 'u' )
+                       break;
+       }
+       // find first space
+       for (;i < old_sz; i++) {
+               if ( old[i] == ' ' || old[i] == '\t' )
+                       break;
+       }
+       if ( i >= old_sz ) {
+               eputs("\nError: can't find correct usbfs entry\n");
+               return 3;
+       }
+       
+       fd = open(name, O_WRONLY|O_CREAT|O_TRUNC);
+       if (fd < 0) {
+               eputs("\nError: can't open file for writing\n");
+               return 4;
+       }
+       write(fd, old, i);
+       write(fd, add, strlen(add));
+       write(fd, old + i, old_sz - i);
+       close(fd);
+       eputs("OK\n");
+       
+       return 0;
+}
+