opt: Don't segfault if a string's default is NULL

[ccan] / ccan / opt / helpers.c

diff --git a/ccan/opt/helpers.c b/ccan/opt/helpers.c
index e531a7d3aa2bc9d250e0608f21f0604d66e13733..43b86d7ca2ad953665522cf37f449b8046ffd3b7 100644 (file)
--- a/ccan/opt/helpers.c
+++ b/ccan/opt/helpers.c
@@ -165,6 +165,12 @@ char *opt_inc_intval(int *i)
        return NULL;
 }
 
+char *opt_dec_intval(int *i)
+{
+       (*i)--;
+       return NULL;
+}
+
 /* Display version string. */
 char *opt_version_and_exit(const char *version)
 {
@@ -196,14 +202,19 @@ void opt_show_invbool(char buf[OPT_SHOW_LEN], const bool *b)
 
 void opt_show_charp(char buf[OPT_SHOW_LEN], char *const *p)
 {
-       size_t len = strlen(*p);
-       buf[0] = '"';
-       if (len > OPT_SHOW_LEN - 2)
-               len = OPT_SHOW_LEN - 2;
-       strncpy(buf+1, *p, len);
-       buf[1+len] = '"';
-       if (len < OPT_SHOW_LEN - 2)
-               buf[2+len] = '\0';
+       if (*p){
+               size_t len = strlen(*p);
+               buf[0] = '"';
+               if (len > OPT_SHOW_LEN - 2)
+                       len = OPT_SHOW_LEN - 2;
+               strncpy(buf+1, *p, len);
+               buf[1+len] = '"';
+               if (len < OPT_SHOW_LEN - 2)
+                       buf[2+len] = '\0';
+       }
+       else {
+               strncpy(buf, "(nil)", OPT_SHOW_LEN);
+       }
 }
 
 /* Show an integer value, various forms. */