Implement but don't use code to use rsync's --compare-dest feature.

One gotcha is that the path passed to --compare-dest needs to be relative
to the dst directory. rsync_fixup_dest() will prepend the necessary ../
for that by counting number of '/' in dst.
OK tb@

diff --git a/usr.sbin/rpki-client/main.c b/usr.sbin/rpki-client/main.c
index fa8d284..1a976d8 100644 (file)
--- a/usr.sbin/rpki-client/main.c
+++ b/usr.sbin/rpki-client/main.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: main.c,v 1.173 2022/01/11 13:06:07 claudio Exp $ */
+/*     $OpenBSD: main.c,v 1.174 2022/01/13 11:50:29 claudio Exp $ */
 /*
  * Copyright (c) 2021 Claudio Jeker <claudio@openbsd.org>
  * Copyright (c) 2019 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -261,6 +261,7 @@ rsync_fetch(unsigned int id, const char *uri, const char *local)
        b = io_new_buffer();
        io_simple_buffer(b, &id, sizeof(id));
        io_str_buffer(b, local);
+       io_str_buffer(b, NULL);
        io_str_buffer(b, uri);
        io_close_buffer(&rsyncq, b);
 }

diff --git a/usr.sbin/rpki-client/rsync.c b/usr.sbin/rpki-client/rsync.c
index 58d2276..c4e6f91 100644 (file)
--- a/usr.sbin/rpki-client/rsync.c
+++ b/usr.sbin/rpki-client/rsync.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: rsync.c,v 1.31 2021/12/22 09:35:14 claudio Exp $ */
+/*     $OpenBSD: rsync.c,v 1.32 2022/01/13 11:50:29 claudio Exp $ */
 /*
  * Copyright (c) 2019 Kristaps Dzonsons <kristaps@bsd.lv>
  *
@@ -99,6 +99,31 @@ rsync_base_uri(const char *uri)
        return base_uri;
 }
 
+/*
+ * The directory passed as --compare-dest needs to be relative to
+ * the destination directory. This function takes care of that.
+ */
+static char *
+rsync_fixup_dest(char *destdir, char *compdir)
+{
+       const char *dotdot = "../../../../../../";      /* should be enough */
+       int dirs = 1;
+       char *fn;
+       char c;
+
+       while ((c = *destdir++) != '\0')
+               if (c == '/')
+                       dirs++;
+
+       if (dirs > 6)
+               /* too deep for us */
+               return NULL;
+
+       if ((asprintf(&fn, "%.*s%s", dirs * 3, dotdot, compdir)) == -1)
+               err(1, NULL);
+       return fn;
+}
+
 static void
 proc_child(int signal)
 {
@@ -181,7 +206,7 @@ proc_rsync(char *prog, char *bind_addr, int fd)
                err(1, NULL);
 
        for (;;) {
-               char *uri = NULL, *dst = NULL;
+               char *uri, *dst, *compdst;
                unsigned int id;
                pid_t pid;
                int st;
@@ -209,7 +234,8 @@ proc_rsync(char *prog, char *bind_addr, int fd)
                                for (i = 0; i < idsz; i++)
                                        if (ids[i].pid == pid)
                                                break;
-                               assert(i < idsz);
+                               if (i >= idsz)
+                                       errx(1, "waitpid: %d unexpected", pid);
 
                                if (!WIFEXITED(st)) {
                                        warnx("rsync %s terminated abnormally",
@@ -261,6 +287,7 @@ proc_rsync(char *prog, char *bind_addr, int fd)
                /* Read host and module. */
                io_read_buf(b, &id, sizeof(id));
                io_read_str(b, &dst);
+               io_read_str(b, &compdst);
                io_read_str(b, &uri);
 
                ibuf_free(b);
@@ -275,6 +302,7 @@ proc_rsync(char *prog, char *bind_addr, int fd)
 
                if (pid == 0) {
                        char *args[32];
+                       char *reldst;
 
                        if (pledge("stdio exec", NULL) == -1)
                                err(1, "pledge");
@@ -295,6 +323,11 @@ proc_rsync(char *prog, char *bind_addr, int fd)
                                args[i++] = "--address";
                                args[i++] = (char *)bind_addr;
                        }
+                       if (compdst != NULL &&
+                           (reldst = rsync_fixup_dest(dst, compdst)) != NULL) {
+                               args[i++] = "--compare-dest";
+                               args[i++] = reldst;
+                       }
                        args[i++] = uri;
                        args[i++] = dst;
                        args[i] = NULL;
@@ -323,6 +356,7 @@ proc_rsync(char *prog, char *bind_addr, int fd)
                /* Clean up temporary values. */
 
                free(dst);
+               free(compdst);
        }
 
        /* No need for these to be hanging around. */