+static int append_signoff(char *buf, int buf_sz, int at, const char *signoff)
+{
+ int signoff_len = strlen(signoff);
+ static const char signed_off_by[] = "Signed-off-by: ";
+ char *cp = buf;
+
+ /* Do we have enough space to add it? */
+ if (buf_sz - at <= strlen(signed_off_by) + signoff_len + 2)
+ return at;
+
+ /* First see if we already have the sign-off by the signer */
+ while (1) {
+ cp = strstr(cp, signed_off_by);
+ if (!cp)
+ break;
+ cp += strlen(signed_off_by);
+ if ((cp + signoff_len < buf + at) &&
+ !strncmp(cp, signoff, signoff_len) &&
+ isspace(cp[signoff_len]))
+ return at; /* we already have him */
+ }
+
+ strcpy(buf + at, signed_off_by);
+ at += strlen(signed_off_by);
+ strcpy(buf + at, signoff);
+ at += signoff_len;
+ buf[at++] = '\n';
+ buf[at] = 0;
+ return at;
+}
+