17/17: Revert "DRAFT daemon: Support chroot builds on GNU/Hurd."

[guix-commits]

janneke pushed a commit to branch hurd-team
in repository guix.

commit 1e8f453384c76cfac4ddaf0732dba5b04185f229
Author: Janneke Nieuwenhuizen <janneke@gnu.org>
AuthorDate: Tue Aug 22 21:51:19 2023 +0200

    Revert "DRAFT daemon: Support chroot builds on GNU/Hurd."
    
    This reverts commit d04d70f6eaedad0ea6cd3b5a48f30666e324fd23.
---
 config-daemon.ac      |  13 -----
 nix/libstore/build.cc |  43 ++++------------
 nix/libutil/util.cc   | 139 --------------------------------------------------
 nix/libutil/util.hh   |   3 --
 nix/local.mk          |   3 +-
 5 files changed, 12 insertions(+), 189 deletions(-)

diff --git a/config-daemon.ac b/config-daemon.ac
index 315f4de28f..86306effe1 100644
--- a/config-daemon.ac
+++ b/config-daemon.ac
@@ -37,19 +37,6 @@ if test "x$guix_build_daemon" = "xyes"; then
   AC_DEFINE_UNQUOTED([SYSTEM], ["$guix_system"],
     [Guix host system type--i.e., platform and OS kernel tuple.])
 
-  dnl On GNU/Hurd guix-daemon depends on libfshelp.
-  case "$guix_system" in
-    *-gnu)
-      AC_CHECK_LIB([fshelp], [fshelp_start_translator])
-      if test "x$ac_cv_lib_fshelp_fshelp_start_translator" != "xyes"; then
-        AC_MSG_ERROR([libfshelp (GNU Hurd) could not be found])
-      fi
-      HURD_LIBS="-lfshelp";;
-    *)
-      HURD_LIBS="";;
-  esac
-  AC_SUBST([HURD_LIBS])
-
   case "$LIBGCRYPT_PREFIX" in
     no)
       LIBGCRYPT_CFLAGS=""
diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index a708202f2b..c5383bc756 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -52,13 +52,7 @@
 #endif
 
 
-/* Chroot builds are supported both on GNU/Linux and on GNU/Hurd.  */
-#if defined __linux__ || defined __GNU__
-# define CHROOT_ENABLED 1
-#else
-# error unsupported operating system
-#endif
-
+#define CHROOT_ENABLED HAVE_CHROOT && HAVE_SYS_MOUNT_H && defined(MS_BIND) && 
defined(MS_PRIVATE)
 #define CLONE_ENABLED defined(CLONE_NEWNS)
 
 #if defined(SYS_pivot_root)
@@ -2004,7 +1998,6 @@ void DerivationGoal::runChild()
             if (setdomainname(domainname, sizeof(domainname)) == -1)
                 throw SysError("cannot set domain name");
 
-#ifdef __linux__
             /* Make all filesystems private.  This is necessary
                because subtrees may have been mounted as "shared"
                (MS_SHARED).  (Systemd does this, for instance.)  Even
@@ -2021,30 +2014,27 @@ void DerivationGoal::runChild()
                different filesystem from /, as needed for pivot_root. */
             if (mount(chrootRootDir.c_str(), chrootRootDir.c_str(), 0, 
MS_BIND, 0) == -1)
                 throw SysError(format("unable to bind mount ‘%1%’") % 
chrootRootDir);
-#endif
 
             /* Set up a nearly empty /dev, unless the user asked to
                bind-mount the host /dev. */
             Strings ss;
             if (dirsInChroot.find("/dev") == dirsInChroot.end()) {
-#ifdef __linux__
                 createDirs(chrootRootDir + "/dev/shm");
                 createDirs(chrootRootDir + "/dev/pts");
-                createSymlink("/proc/self/fd", chrootRootDir + "/dev/fd");
-                createSymlink("/proc/self/fd/0", chrootRootDir + "/dev/stdin");
-                createSymlink("/proc/self/fd/1", chrootRootDir + 
"/dev/stdout");
-                createSymlink("/proc/self/fd/2", chrootRootDir + 
"/dev/stderr");
-                ss.push_back("/dev/tty");
+                ss.push_back("/dev/full");
+#ifdef __linux__
                 if (pathExists("/dev/kvm"))
                     ss.push_back("/dev/kvm");
-#elif __GNU__
-               ss.push_back("/servers");
 #endif
-                ss.push_back("/dev/full");
                 ss.push_back("/dev/null");
                 ss.push_back("/dev/random");
+                ss.push_back("/dev/tty");
                 ss.push_back("/dev/urandom");
                 ss.push_back("/dev/zero");
+                createSymlink("/proc/self/fd", chrootRootDir + "/dev/fd");
+                createSymlink("/proc/self/fd/0", chrootRootDir + "/dev/stdin");
+                createSymlink("/proc/self/fd/1", chrootRootDir + 
"/dev/stdout");
+                createSymlink("/proc/self/fd/2", chrootRootDir + 
"/dev/stderr");
             }
 
             /* Fixed-output derivations typically need to access the
@@ -2066,7 +2056,7 @@ void DerivationGoal::runChild()
                 struct stat st;
                 Path source = i->second;
                 Path target = chrootRootDir + i->first;
-
+                if (source == "/proc") continue; // backwards compatibility
                 if (stat(source.c_str(), &st) == -1)
                     throw SysError(format("getting attributes of path `%1%'") 
% source);
                 if (S_ISDIR(st.st_mode))
@@ -2075,11 +2065,10 @@ void DerivationGoal::runChild()
                     createDirs(dirOf(target));
                     writeFile(target, "");
                 }
-                if (firmlink(source, target) == -1)
+                if (mount(source.c_str(), target.c_str(), "", MS_BIND, 0) == 
-1)
                     throw SysError(format("bind mount from `%1%' to `%2%' 
failed") % source % target);
             }
 
-#ifdef __linux__
             /* Bind a new instance of procfs on /proc to reflect our
                private PID namespace. */
             createDirs(chrootRootDir + "/proc");
@@ -2107,16 +2096,11 @@ void DerivationGoal::runChild()
                    Linux versions, it is created with permissions 0.  */
                 chmod_(chrootRootDir + "/dev/pts/ptmx", 0666);
             }
-#elif __GNU__
-           /* Do not mount things that are implemented in user land: /proc,
-              /dev/shm, /dev/pts, etc.  */
-#endif
 
             /* Do the chroot(). */
             if (chdir(chrootRootDir.c_str()) == -1)
                 throw SysError(format("cannot change directory to '%1%'") % 
chrootRootDir);
 
-#ifdef __linux__
             if (mkdir("real-root", 0) == -1)
                 throw SysError("cannot create real-root directory");
 
@@ -2131,13 +2115,8 @@ void DerivationGoal::runChild()
 
             if (rmdir("real-root") == -1)
                 throw SysError("cannot remove real-root directory");
-#elif __GNU__
-            if (chroot(".") == -1)
-                throw SysError(format("cannot change root directory to '%1%'") 
% chrootRootDir);
-
-#endif
         }
-#endif // CHROOT_ENABLED
+#endif
 
         if (chdir(tmpDirInSandbox.c_str()) == -1)
             throw SysError(format("changing into `%1%'") % tmpDir);
diff --git a/nix/libutil/util.cc b/nix/libutil/util.cc
index 62ddec8126..82eac72120 100644
--- a/nix/libutil/util.cc
+++ b/nix/libutil/util.cc
@@ -23,41 +23,6 @@
 #include <sys/prctl.h>
 #endif
 
-#if HAVE_SYS_MOUNT_H
-#include <sys/mount.h>
-#endif
-
-#ifdef __GNU__
-
-extern "C" {
-
-/* XXX: <idvec.h> uses 'new' as a parameter name.  Work around it.  */
-# define new new_param
-
-# include <hurd.h>
-# include <hurd/paths.h>
-# include <hurd/fsys.h>
-# include <argz.h>
-
-# undef new
-
-/* XXX: <fshelp.h> is not C++-compatible.  Copy these declarations to work
-   around it.  */
-
-typedef error_t (*fshelp_open_fn_t) (int flags,
-                                    file_t *node,
-                                    mach_msg_type_name_t *node_type,
-                                    task_t, void *cookie);
-
-extern error_t
-fshelp_start_translator (fshelp_open_fn_t underlying_open_fn, void *cookie,
-                        char *name, char *argz, int argz_len,
-                        int timeout, fsys_t *control);
-
-}
-
-# define _HURD_FIRMLINK  _HURD "firmlink"
-#endif
 
 extern char * * environ;
 
@@ -249,89 +214,6 @@ bool isLink(const Path & path)
     return S_ISLNK(st.st_mode);
 }
 
-#if __linux__
-
-int firmlink(const Path &source, const Path &target)
-{
-    return mount(source.c_str(), target.c_str(), "", MS_BIND, 0);
-}
-
-#elif __GNU__
-
-static error_t return_node (int flags,
-                           mach_port_t *underlying,
-                           mach_msg_type_name_t *underlying_type,
-                           task_t task, void *node)
-{
-    *underlying = * (mach_port_t *) node;
-    *underlying_type = MACH_MSG_TYPE_COPY_SEND;
-
-    return ESUCCESS;
-}
-
-int firmlink(const Path &source, const Path &target)
-{
-    static char firmlink[] = _HURD_FIRMLINK;
-    char *arg_vec[] = { firmlink, (char *) source.c_str (), NULL };
-    char *args = NULL;
-    size_t args_len;
-
-    error_t err;
-    file_t target_file = MACH_PORT_NULL;
-
-    printMsg (lvlChatty, format("creating firmlink from '%1%' to '%2%'")
-             % source % target);
-
-    target_file = file_name_lookup (target.c_str (), O_NOTRANS, 0);
-    if (! MACH_PORT_VALID (target_file)) {
-       printMsg (lvlChatty, format("firmlink target '%s' unavailable: %s")
-                 % target % strerror (errno));
-       goto fail;
-    }
-
-    err = argz_create (arg_vec, &args, &args_len);
-    if (err != 0) goto fail;
-
-    mach_port_t control;
-    err = fshelp_start_translator (return_node, &target_file,
-                                  firmlink, args, args_len,
-                                  3000, &control);
-    if (err) {
-       printMsg (lvlChatty, format("failed to start '%s' translator: %s") %
-                 firmlink % strerror(errno));
-       goto fail;
-    }
-
-    free ((void *) args);
-    args = NULL;
-
-    err = (error_t) file_set_translator (target_file, 0, FS_TRANS_SET, 0,
-                                        NULL, 0,
-                                        control, MACH_MSG_TYPE_COPY_SEND);
-    mach_port_deallocate (mach_task_self (), control);
-    mach_port_deallocate (mach_task_self (), target_file);
-
-    if (err) {
-       printMsg (lvlChatty, format("failed to set '%s' translator on node 
'%s': %s") %
-                 firmlink % target % strerror(errno));
-       goto fail;
-    }
-
-    return err;
-
-fail:
-    int saved_errno = errno;
-    if (MACH_PORT_VALID (target_file))
-       mach_port_deallocate (mach_task_self (), target_file);
-    if (args != NULL)
-       free ((void *) args);
-    errno = saved_errno;
-    return -1;
-}
-
-#elif
-# error unsupported operating system
-#endif
 
 DirEntries readDirectory(const Path & path)
 {
@@ -429,27 +311,6 @@ static void _deletePath(const Path & path, unsigned long 
long & bytesFreed, size
 
     printMsg(lvlVomit, format("%1%") % path);
 
-#ifdef __GNU__
-    /* Check whether there's an active translator on PATH--typically
-       /hurd/firmlink.  If there is one, let it go away.  */
-    {
-       file_t file = file_name_lookup (path.c_str (), O_NOTRANS, 0);
-       if (MACH_PORT_VALID (file)) {
-           fsys_t fsys;
-           int err = file_get_translator_cntl (file, &fsys);
-           mach_port_deallocate (mach_task_self (), file);
-           if (err == 0) {
-               /* There's a translator, tell it to leave.  */
-               err = fsys_goaway (fsys, FSYS_GOAWAY_FORCE | 
FSYS_GOAWAY_RECURSE);
-               mach_port_deallocate (mach_task_self (), fsys);
-               if (err != 0) {
-                   throw SysError(format("removing translator from '%1%'") % 
path);
-               }
-           }
-       }
-    }
-#endif
-
 #ifdef HAVE_STATX
 # define st_mode stx_mode
 # define st_size stx_size
diff --git a/nix/libutil/util.hh b/nix/libutil/util.hh
index 2f33735e12..880b0e93b2 100644
--- a/nix/libutil/util.hh
+++ b/nix/libutil/util.hh
@@ -63,9 +63,6 @@ Path readLink(const Path & path);
 
 bool isLink(const Path & path);
 
-/* Make TARGET a firmlink (aka. "bind mount") to SOURCE.  */
-int firmlink(const Path & source, const Path & target);
-
 /* Read the contents of a directory.  The entries `.' and `..' are
    removed. */
 struct DirEntry
diff --git a/nix/local.mk b/nix/local.mk
index f1094e26fb..61d59937e8 100644
--- a/nix/local.mk
+++ b/nix/local.mk
@@ -124,8 +124,7 @@ guix_daemon_CPPFLAGS =                              \
 
 guix_daemon_LDADD =                            \
   libstore.a libutil.a libformat.a -lz         \
-  $(SQLITE3_LIBS) $(LIBGCRYPT_LIBS)            \
-  $(HURD_LIBS)
+  $(SQLITE3_LIBS) $(LIBGCRYPT_LIBS)
 
 guix_daemon_headers =                          \
   %D%/nix-daemon/shared.hh