1 files changed, 40 insertions, 2 deletions
diff --git a/toys/lsb/hostname.c b/toys/lsb/hostname.c
index 23467fb3..ebfc803c 100644
--- a/toys/lsb/hostname.c
+++ b/toys/lsb/hostname.c
@@ -4,23 +4,61 @@
  *
  * http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/hostname.html
 
-USE_HOSTNAME(NEWTOY(hostname, NULL, TOYFLAG_BIN))
+USE_HOSTNAME(NEWTOY(hostname, "bF:", TOYFLAG_BIN))
 
 config HOSTNAME
   bool "hostname"
   default y
   help
-    usage: hostname [newname]
+    usage: hostname [-b] [-F FILENAME] [newname]
 
     Get/Set the current hostname
+
+    -b  Set hostname to 'localhost' if otherwise unset
+    -F  Set hostname to contents of FILENAME
 */
 
 #define FOR_hostname
 #include "toys.h"
 
+GLOBALS(
+  char *fname;
+)
+
 void hostname_main(void)
 {
   const char *hostname = toys.optargs[0];
+
+  if (toys.optflags & FLAG_F) {
+    char *buf;
+    if ((hostname = buf = readfile(TT.fname, 0, 0))) {
+      size_t len = strlen(hostname);
+      char *end = buf + len - 1;
+
+      /* Trim trailing whitespace. */
+      while (len && isspace(*end)) {
+        *end-- = '\0';
+        len--;
+      }
+      if (!len) {
+        free(buf);
+        hostname = NULL;
+        if (!(toys.optflags & FLAG_b))
+          error_exit("empty file '%s'", TT.fname);
+      }
+    } else if (!(toys.optflags & FLAG_b))
+      error_exit("failed to read '%s'", TT.fname);
+  }
+
+  if (!hostname && toys.optflags & FLAG_b) {
+    /* Do nothing if hostname already set. */
+    if (gethostname(toybuf, sizeof(toybuf))) perror_exit("get failed");
+    if (strnlen(toybuf, sizeof(toybuf))) exit(0);
+
+    /* Else set hostname to localhost. */
+    hostname = "localhost";
+  }
+
   if (hostname) {
     if (sethostname(hostname, strlen(hostname)))
       perror_exit("set failed '%s'", hostname);