dma: fix various bugs in local mbox delivery

diff --git a/local.c b/local.c
index 887491c8407003c1fba8f33d977babd3b2493d82..5515177a643e257cc297199089bcfce532579df8 100644 (file)
--- a/local.c
+++ b/local.c
@@ -14,9 +14,12 @@ deliver_local(struct qitem *it, const char **errmsg)
 {
        char fn[PATH_MAX+1];
        char line[1000];
+       const char *sender;
+       const char *newline = "\n";
        size_t linelen;
        int mbox;
        int error;
+       int hadnl = 0;
        off_t mboxlen;
        time_t now = time(NULL);
 
@@ -32,14 +35,23 @@ deliver_local(struct qitem *it, const char **errmsg)
                syslog(LOG_NOTICE, "local delivery deferred: can not open `%s': %m", fn);
                return (1);
        }
-       mboxlen = lseek(mbox, 0, SEEK_CUR);
+       mboxlen = lseek(mbox, 0, SEEK_END);
+
+       /* New mails start with \nFrom ...., unless we're at the beginning of the mbox */
+       if (mboxlen == 0)
+               newline = "";
+
+       /* If we're bouncing a message, claim it comes from MAILER-DAEMON */
+       sender = it->sender;
+       if (strcmp(sender, "") == 0)
+               sender = "MAILER-DAEMON";
 
        if (fseek(it->mailf, it->hdrlen, SEEK_SET) != 0) {
                syslog(LOG_NOTICE, "local delivery deferred: can not seek: %m");
                return (1);
        }
 
-       error = snprintf(line, sizeof(line), "From %s\t%s", it->sender, ctime(&now));
+       error = snprintf(line, sizeof(line), "%sFrom %s\t%s", newline, sender, ctime(&now));
        if (error < 0 || (size_t)error >= sizeof(line)) {
                syslog(LOG_NOTICE, "local delivery deferred: can not write header: %m");
                return (1);
@@ -58,18 +70,20 @@ deliver_local(struct qitem *it, const char **errmsg)
                        goto chop;
                }
 
-               if (strncmp(line, "From ", 5) == 0) {
+               if (hadnl && strncmp(line, "From ", 5) == 0) {
                        const char *gt = ">";
 
                        if (write(mbox, gt, 1) != 1)
                                goto wrerror;
+                       hadnl = 0;
+               } else if (strcmp(line, "\n") == 0) {
+                       hadnl = 1;
+               } else {
+                       hadnl = 0;
                }
                if ((size_t)write(mbox, line, linelen) != linelen)
                        goto wrerror;
        }
-       line[0] = '\n';
-       if (write(mbox, line, 1) != 1)
-               goto wrerror;
        close(mbox);
        return (0);