From db3fb428599c9c8fe105dcf4ba8d1c914c54cc26 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Thu, 15 Oct 2026 08:19:48 +0000
Subject:  More work on format-upgrade inclusion: real meta-information storage

 If a db format upgrade is necessary, we need to compile the snapshot
with the new s6-rc-compile. There's data we need to pass to it that
isn't stored (options passed when committing the original set), so
we store it in the db itself (patching s6-rc-compile). We modify
the s6-rc-compile wrappers to pass all this metadata.

 Next, we will compile the snapshot.
---
 doc/s6-rc-compile.html          |  6 +++++-
 src/include/s6-rc/repo.h        |  1 +
 src/repo/deps-lib/s6rcrepo      |  1 +
 src/repo/s6rc_repo_compile.c    | 14 ++++++++++----
 src/repo/s6rc_repo_read_major.c | 15 ++++++---------
 src/repo/s6rc_repo_setcompile.c |  2 +-
 src/s6-rc/s6-rc-compile.c       | 41 ++++++++++++++++++++++++++---------------
 7 files changed, 50 insertions(+), 30 deletions(-)

diff --git a/doc/s6-rc-compile.html b/doc/s6-rc-compile.html
index 09e71d6..0d9f712 100644
--- a/doc/s6-rc-compile.html
+++ b/doc/s6-rc-compile.html
@@ -37,7 +37,7 @@ the current service database via
 <h2> Interface </h2>
 
 <pre>
-     s6-rc-compile [ -v <em>verbosity</em> ] [ -h <em>fdhuser</em> ] [ -L <em>catchall</em> ] [ -b ] <em>compiled</em> <em>source...</em>
+     s6-rc-compile [ -v <em>verbosity</em> ] [ -h <em>fdhuser</em> ] [ -L <em>catchall</em> ] [ -D <em>defbundle</em> ] [ -b ] <em>compiled</em> <em>source...</em>
 </pre>
 
 <ul>
@@ -75,6 +75,10 @@ logger service will be running on <em>catchall</em> and ensure that its
 fifo is properly held in the fdholder (which avoids services getting killed
 by SIGPIPE if they're writing uncaught logs while the catch-all logger is
 restarting). </li>
+ <li> <tt>-D&nbsp;<em>defbundle</em></tt>&nbsp;: register <em>defbundle</em>
+as the default bundle started at boot time. For now it is purely indicative
+and used by the repo commands for consistency purposes; it might become
+semantically important in the future. </li>
  <li> <tt>-b</tt>&nbsp;: make
 <a href="s6-rc-oneshot-run.html">s6-rc-oneshot-run</a>
 invocations wait instead of fail on lock contention. This
diff --git a/src/include/s6-rc/repo.h b/src/include/s6-rc/repo.h
index 6ecec15..6c9b17b 100644
--- a/src/include/s6-rc/repo.h
+++ b/src/include/s6-rc/repo.h
@@ -26,6 +26,7 @@ extern int s6rc_repo_ls (char const *, stralloc *, genalloc *) ;
 extern char const s6rc_repo_rxnames[4][7] ;
 
 extern uint32_t s6rc_repo_read_major (char const *) ; /* the major a db was compiled with */
+extern int s6rc_repo_install_needs_upgrade (char const *) ;
 
 extern int s6rc_repo_makestores (char const *, char const *const *, uint16_t, char *) ;
 
diff --git a/src/repo/deps-lib/s6rcrepo b/src/repo/deps-lib/s6rcrepo
index aee5f34..eb1ead9 100644
--- a/src/repo/deps-lib/s6rcrepo
+++ b/src/repo/deps-lib/s6rcrepo
@@ -7,6 +7,7 @@ s6rc_repo_fillset.o
 s6rc_repo_fixset.o
 s6rc_repo_flattenservices.o
 s6rc_repo_getserviceflags.o
+s6rc_repo_install_needs_upgrade.o
 s6rc_repo_list_sets.o
 s6rc_repo_listalldeps.o
 s6rc_repo_listcontents.o
diff --git a/src/repo/s6rc_repo_compile.c b/src/repo/s6rc_repo_compile.c
index f89a65a..fc7d8ea 100644
--- a/src/repo/s6rc_repo_compile.c
+++ b/src/repo/s6rc_repo_compile.c
@@ -16,12 +16,13 @@
 #include <s6-rc/config.h>
 #include <s6-rc/repo.h>
 
-int s6rc_repo_compile (char const *repo, char const *set, char const *const *rxs, uint8_t nrxs, char *oldc, unsigned int verbosity, char const *fdhuser, char const *catchall)
+int s6rc_repo_compile (char const *repo, char const *set, char const *const *rxs, uint8_t nrxs, char *oldc, unsigned int verbosity, char const *fdhuser, char const *catchall, char const *defbundle)
 {
   size_t repolen = strlen(repo) ;
   size_t setlen = strlen(set) ;
   size_t totrxlen = 0 ;
   int needprefix = strcmp(set, ".ref") ;
+  int needsnapshot = needprefix && memcmp(set, ".snapshot.", 10) ;
   char snap[setlen + 44] ;
   char newc[repolen + setlen + 45] ;
   memcpy(newc, repo, repolen) ;
@@ -38,7 +39,7 @@ int s6rc_repo_compile (char const *repo, char const *set, char const *const *rxs
     pid_t pid ;
     size_t m = 0 ;
     int wstat ;
-    char const *argv[11 + nrxs] ;
+    char const *argv[13 + nrxs] ;
     char fmtv[UINT_FMT] ;
     char src[nrxs * (repolen + 10 + (needprefix ? setlen + 1 : 0)) + totrxlen] ;
     char *w = src ;
@@ -57,6 +58,11 @@ int s6rc_repo_compile (char const *repo, char const *set, char const *const *rxs
       argv[m++] = "-L" ;
       argv[m++] = catchall ;
     }
+    if (defbundle)
+    {
+      argv[m++] = "-D" ;
+      argv[m++] = defbundle ;
+    }
     argv[m++] = "--" ;
     argv[m++] = newc ;
     for (uint8_t i = 0 ; i < nrxs ; i++)
@@ -96,7 +102,7 @@ int s6rc_repo_compile (char const *repo, char const *set, char const *const *rxs
     }
   }
 
-  if (needprefix)
+  if (needsnapshot)
   {
     int e ;
     memcpy(snap, ".snapshot", 9) ;
@@ -124,7 +130,7 @@ int s6rc_repo_compile (char const *repo, char const *set, char const *const *rxs
     {
       int e = errno ;
       rm_rf(newc) ;
-      if (needprefix) s6rc_repo_setdelete(repo, snap) ;
+      if (needsnapshot) s6rc_repo_setdelete(repo, snap) ;
       errno = e ;
       strerr_warnfu4sys("atomically symlink ", newc + repolen + 10, " to ", fn) ;
       return -1 ;
diff --git a/src/repo/s6rc_repo_read_major.c b/src/repo/s6rc_repo_read_major.c
index 08d646b..1501fe2 100644
--- a/src/repo/s6rc_repo_read_major.c
+++ b/src/repo/s6rc_repo_read_major.c
@@ -16,15 +16,12 @@ uint32_t s6rc_repo_read_major (char const *compiled)
   size_t clen = strlen(compiled) ;
   ssize_t r ;
   uint32_t res ;
-  char tmp[UINT32_FMT] ;
-  char fn[clen + 7] ;
+  char pack[5] ;
+  char fn[clen + 16] ;
   memcpy(fn, compiled, clen) ;
-  memcpy(fn + clen, "/major", 7) ;
-  r = openreadnclose(fn, tmp, UINT32_FMT) ;
-  if (r == -1) return errno == ENOENT ? 7 : 0 ; /* up to 0.7.0.0 doesn't have db/major */
-  if (!r) return 0 ;
-  if (tmp[r] != '\n') return (errno = EPROTO, 0) ;
-  tmp[r] = 0 ;
-  if (uint320_scan(tmp, &res) != r) return (errno = EPROTO, 0) ;
+  memcpy(fn + clen, "/metainfo/major", 16) ;
+  r = openreadnclose(fn, pack, 5) ;
+  if (r != 4) return r == -1 && errno == ENOENT ? 7 : 0 ; /* up to 0.7.0.0 doesn't have metainfo */
+  uint32_unpack_big(pack, &res) ;
   return res ;
 }
diff --git a/src/repo/s6rc_repo_setcompile.c b/src/repo/s6rc_repo_setcompile.c
index 1bdbea8..f894f64 100644
--- a/src/repo/s6rc_repo_setcompile.c
+++ b/src/repo/s6rc_repo_setcompile.c
@@ -13,7 +13,7 @@ int s6rc_repo_setcompile (char const *repo, char const *set, char const *defbund
   int r ;
   if (!s6rc_repo_makesetbundles(repo, set, verbosity)) return -1 ;
   if (!s6rc_repo_makedefbundle(repo, set, defbundle)) return -1 ;
-  r = s6rc_repo_compile(repo, set, rxs, 4, oldc, verbosity, fdhuser, catchall) ;
+  r = s6rc_repo_compile(repo, set, rxs, 4, oldc, verbosity, fdhuser, catchall, defbundle) ;
 
   {
     int e = errno ;
diff --git a/src/s6-rc/s6-rc-compile.c b/src/s6-rc/s6-rc-compile.c
index 0bfe4d7..8e9af59 100644
--- a/src/s6-rc/s6-rc-compile.c
+++ b/src/s6-rc/s6-rc-compile.c
@@ -21,7 +21,7 @@
 #include <s6-rc/config.h>
 #include <s6-rc/s6rc.h>
 
-#define USAGE "s6-rc-compile [ -v verbosity ] [ -h fdholder-user ] [ -L catchall-logger ] [ -b ] destdir sources..."
+#define USAGE "s6-rc-compile [ -v verbosity ] [ -h fdholder-user ] [ -L catchall-logger ] [ -D default-bundle ] [ -b ] destdir sources..."
 #define dieusage() strerr_dieusage(100, USAGE)
 #define dienomem() strerr_dief(111, "out of memory") ;
 
@@ -37,6 +37,7 @@ enum gola_e
   GOLA_VERBOSITY,
   GOLA_FDHUSER,
   GOLA_CATCHALL,
+  GOLA_DEFBUNDLE,
   GOLA_N
 } ;
 
@@ -1604,19 +1605,26 @@ static inline void write_db (char const *compiled, s6rc_db_t const *db)
   strerr_diefusys(111, "write to ", dbfn) ;
 }
 
-static inline void write_major (char const *compiled)
+static inline void write_meta (char const *compiled, char const *fdhuser, char const *catchall)
 {
-  uint32_t version = s6rc_get_major(S6RC_VERSION) ;
-  size_t len ;
-  char fmt[UINT32_FMT] ;
-  if (!version)
-  {
-    cleanup(compiled) ;
-    strerr_dief(101, "invalid software version: ", S6RC_VERSION) ;
-  }
-  len = uint32_fmt(fmt, version) ;
-  fmt[len++] = '\n' ;
-  auto_file(compiled, "major", fmt, len) ;
+  char pack[4] ;
+  char fn[19] ;
+
+  memcpy(fn, "metainfo", 9) ;
+  auto_dir(compiled, fn) ;
+
+  memcpy(fn + 8, "/major", 7) ;
+  uint32_pack_big(pack, s6rc_get_major(S6RC_VERSION)) ;
+  auto_file(compiled, fn, pack, 4) ;
+
+  memcpy(fn + 9, "fdhuser", 8) ;
+  auto_file(compiled, fn, fdhuser ? fdhuser : "", fdhuser ? strlen(fdhuser) : 0) ;
+
+  memcpy(fn + 9, "catchall", 9) ;
+  auto_file(compiled, fn, catchall ? catchall : "", catchall ? strlen(catchall) : 0) ;
+
+  memcpy(fn + 9, "defbundle", 10) ;
+  auto_file(compiled, fn, defbundle ? defbundle : "", defbundle ? strlen(defbundle) : 0) ;
 }
 
 static inline void write_compiled (
@@ -1628,11 +1636,12 @@ static inline void write_compiled (
   uint32_t const *bdeps,
   char const *fdhuser,
   char const *catchall,
+  char const *defbundle,
   int blocking)
 {
   if (verbosity >= 2) strerr_warni("writing compiled information to ", compiled) ;
   init_compiled(compiled) ;
-  write_major(compiled) ;
+  write_meta(compiled, fdhuser, catchall, defbundle) ;
   write_sizes(compiled, db) ;
   write_resolve(compiled, db, bundles, nbundles, bdeps) ;
   stralloc_free(&data) ;
@@ -1653,6 +1662,7 @@ int main (int argc, char const *const *argv)
     { .so = 'v', .lo = "verbosity", .i = GOLA_VERBOSITY },
     { .so = 'h', .lo = "fdholder-user", .i = GOLA_FDHUSER },
     { .so = 'L', .lo = "catchall-logger", .i = GOLA_CATCHALL },
+    { .so = 'D', .lo = "default-bundle", .i = GOLA_DEFBUNDLE },
   } ;
   before_t before = BEFORE_ZERO ;
   uint64_t wgolb = 0 ;
@@ -1660,6 +1670,7 @@ int main (int argc, char const *const *argv)
   char const *compiled ;
   unsigned int golc ;
   PROG = "s6-rc-compile" ;
+  wgola[GOLA_DEFBUNDLE] = S6RC_DEFBUNDLE ;
 
   golc = GOL_main(argc, argv, rgolb, rgola, &wgolb, wgola) ;
   argc -= golc ; argv += golc ;
@@ -1722,7 +1733,7 @@ int main (int argc, char const *const *argv)
       db.deps = deps ;
       flatlist_services(&db, sarray) ;
       propagate_bundle_flags(&db, bundles, nbundles, bdeps) ;
-      write_compiled(compiled, &db, srcdirs, bundles, nbundles, bdeps, wgola[GOLA_FDHUSER], wgola[GOLA_CATCHALL], wgolb & GOLB_BLOCK) ;
+      write_compiled(compiled, &db, srcdirs, bundles, nbundles, bdeps, wgola[GOLA_FDHUSER], wgola[GOLA_CATCHALL], wgola[GOLA_DEFBUNDLE], wgolb & GOLB_BLOCK) ;
     }
   }
 
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