dhcpc: fix the case where we might add extra space at the end of envvar.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 10 insertions, 9 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index d9269f277..d67769e65 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -173,16 +173,13 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_
         dest += sprintf(ret, "%s=", opt_name);
 
         while (len >= optlen) {
-                unsigned ip_ofs = 0;
-
                 switch (type) {
+                case OPTION_IP:
                 case OPTION_IP_PAIR:
                         dest += sprint_nip(dest, "", option);
-                        *dest++ = '/';
-                        ip_ofs = 4;
-                        /* fall through */
-                case OPTION_IP:
-                        dest += sprint_nip(dest, "", option + ip_ofs);
+                        if (type == OPTION_IP)
+                                break;
+                        dest += sprint_nip(dest, "/", option + 4);
                         break;
 //              case OPTION_BOOLEAN:
 //                      dest += sprintf(dest, *option ? "yes" : "no");
@@ -204,10 +201,14 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_
                         dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
                         break;
                 }
+                /* Note: options which use 'return' instead of 'break'
+                 * (for example, OPTION_STRING) skip the code which handles
+                 * the case of list of options.
+                 */
                 case OPTION_STRING:
                         memcpy(dest, option, len);
                         dest[len] = '\0';
-                        return ret;      /* Short circuit this case */
+                        return ret;
                 case OPTION_STATIC_ROUTES: {
                         /* Option binary format:
                          * mask [one byte, 0..32]
@@ -347,7 +348,7 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_
 // TODO: it can be a list only if (optflag->flags & OPTION_LIST).
 // Should we bail out/warn if we see multi-ip option which is
 // not allowed to be such (for example, DHCP_BROADCAST)? -
-                if (len <= 0 /* || !(optflag->flags & OPTION_LIST) */)
+                if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
                         break;
                 *dest++ = ' ';
                 *dest = '\0';