Re: Adding pkg_admin unpack (ish)

[Anthony Mallet <anthony.mallet%laas.fr@localhost>]

On Saturday 13 Apr 2024, at 12:47, Greg Troxel wrote:
> Anthony Mallet <anthony.mallet%laas.fr@localhost> writes:
> > I actually implemented `pkg_add -x pkg.tgz`, it's only a few
> > lines diff, and for me it's the simplest solution, as by definition
> > pkg_add will be available on the host and it will have a consistent
> > behaviour.
>
> Feel free to send a patch for people to think about.

Here is the current draft (-p0 from inside pkgtools/pkg_install/files).

pkg_admin would seem like a better choice for the 'unpack' option, but
pkg_admin mostly deals with the pkgdb, so it does not have any of the
archive processing logic. So I patched pkg_add instead, adding a `-x'
option, which makes the diff short.

What the patch does is simply skipping the platform check and
dependency management part of pkg_do() in add/perform.c. So, for
instance, the signature, license and vulnerability checks remain
active. That might be important since the PLIST will be processed
(e.g. @exec). Skipping is done with 'goto', which I think is more
readable in this context.

Meta-data is extracted to '.'. The contents are also extracted to '.'
or to the directory specified in -P. So for instance, in my use case,
preparing the contents of a .deb package is just something like
`mkdir -p /tmproot/DEBIAN && cd /tmproot/DEBIAN && pkg_add -P /tmproot -x pkg.tgz`
That populates 'DEBIAN' with meta-data files (later used by some shell
script magic) and /tmproot with the contents.

There is currently an issue if specifying more than one package to
extract on the command line: meta-data will be incorrect, since no
<pkgname> prefix is used (that's on purpose for my use-case). I also
noticed that if a relative -P directory is given, this fails for the
second and next packages because pkg_do does chdir(2) (but this is an
issue already present in pkg_add).

Any feedback appreciated!
Best,
Anthony

diff --git pkgtools/pkg_install/dist/add/add.h pkgtools/pkg_install/dist/add/add.h
index a55f40bb5..fae545228 100644
--- add/add.h
+++ add/add.h
@@ -35,6 +35,7 @@ extern Boolean NoInstall;
 extern Boolean NoRecord;
 extern Boolean Force;
 extern Boolean Automatic;
+extern Boolean Extract;
 extern int LicenseCheck;
 extern int Replace;
 extern int ReplaceSame;
diff --git add/main.c add/main.c
index 8abf03e79..0a2290903 100644
--- add/main.c
+++ add/main.c
@@ -36,7 +36,7 @@ __RCSID("$NetBSD: main.c,v 1.32 2015/12/27 12:36:42 joerg Exp $");
 #include "lib.h"
 #include "add.h"
 
-static char Options[] = "AC:DIK:P:RVfhm:np:t:Uuv";
+static char Options[] = "AC:DIK:P:RVfhm:np:t:Uuvx";
 
 char   *Destdir = NULL;
 char   *OverrideMachine = NULL;
@@ -44,6 +44,7 @@ char   *Prefix = NULL;
 Boolean NoInstall = FALSE;
 Boolean NoRecord = FALSE;
 Boolean Automatic = FALSE;
+Boolean Extract = FALSE;
 Boolean ForceDepends = FALSE;
 /*
  * Normally, updating fails if the dependencies of a depending package
@@ -139,6 +140,13 @@ main(int argc, char **argv)
 			Verbose = TRUE;
 			break;
 
+		case 'x':
+			Extract = TRUE;
+			NoRecord = TRUE;
+			if (Destdir == NULL)
+				Destdir = ".";
+			break;
+
 		case 'h':
 		case '?':
 		default:
diff --git add/perform.c add/perform.c
index d4b2ebafc..fe5e855d6 100644
--- add/perform.c
+++ add/perform.c
@@ -1561,6 +1561,11 @@ pkg_do(const char *pkgpath, int mark_automatic, int top_level)
 	if (pkg->meta_data.meta_mtree != NULL)
 		warnx("mtree specification in pkg `%s' ignored", pkg->pkgname);
 
+	if (Extract) {
+		pkg->install_logdir = xstrdup(".");
+                goto extract;
+	}
+
 	pkg->logdir = xasprintf("%s/%s", config_pkg_dbdir, pkg->pkgname);
 
 	if (Destdir != NULL)
@@ -1643,9 +1648,18 @@ pkg_do(const char *pkgpath, int mark_automatic, int top_level)
 	if (run_install_script(pkg, "PRE-INSTALL"))
 		goto nuke_pkgdb;
 
+extract:
+	if (Extract && write_meta_data(pkg))
+		goto nuke_pkgdb;
+
 	if (extract_files(pkg))
 		goto nuke_pkg;
 
+	if (Extract) {
+		status = 0;
+		goto clean_memory;
+	}
+
 	if (run_install_script(pkg, "POST-INSTALL"))
 		goto nuke_pkg;
 
diff --git add/pkg_add.1 add/pkg_add.1
index 127a99f3c..ff55a399a 100644
--- add/pkg_add.1
+++ add/pkg_add.1
@@ -25,7 +25,7 @@
 .Nd a utility for installing and upgrading software package distributions
 .Sh SYNOPSIS
 .Nm
-.Op Fl AfhInRUuVv
+.Op Fl AfhInRUuVvx
 .Op Fl C Ar config
 .Op Fl K Ar pkg_dbdir
 .Op Fl m Ar machine
@@ -177,6 +177,14 @@ See below for a more detailed description of the process.
 Print version number and exit.
 .It Fl v
 Turn on verbose output.
+.It Fl x
+Extract the files contained by the packages in the current directory, or in
+the directory specified by
+.Fl P .
+Meta-data files are written to the current directory (regardless of any
+directory specified by
+.Fl P ) .
+No other action is performed.
 .El
 .Pp
 One or more