From bb4aaaa2e8e4bdfc02f9d98ab2982074051c4eb2 Mon Sep 17 00:00:00 2001

Message-ID: <bb4aaaa2e8e4bdfc02f9d98ab2982074051c4eb2.1702642817.git.pmatilai@redhat.com>

From: Panu Matilainen <pmatilai@redhat.com>

Date: Fri, 15 Dec 2023 13:15:29 +0200

Subject: [PATCH] Fix regression in Lua scriptlet runaway child detection

Commit a8107659ef3dd4855729bf65aa4d70f784cb5a5f moved the detection

to parent using waitpid(), but this causes it to complain on any

process in the same process group. In the usual rpm context we don't

have any, but we can't very well tell API users not to have any

children. And then failed to detect a runaway Lua child in one of

our own tests. Uff.

rpmlog() in the child has the issues mentioned in the originating

commit, but that's a problem that needs to be solved elsewhere.

Revert back to issuing a warning when we actually *are* in the child

process, so there are no false positive possible. Use EXIT_FAILURE

like in the original version, dunno why I'd changed that.

Update the rpmlua test to expect the deserved warning, and use

stdio for printing its "normal" output, the catch there is that we

need to flush the io in the child.

Reported at https://bugzilla.redhat.com/show_bug.cgi?id=2254463

---

 rpmio/rpmlua.c    | 10 +++-------

 tests/rpmmacro.at |  9 ++++-----

 2 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/rpmio/rpmlua.c b/rpmio/rpmlua.c

index 8ef90e779..854fd469d 100644

--- a/rpmio/rpmlua.c

+++ b/rpmio/rpmlua.c

@@ -239,17 +239,13 @@ static int luaopt(int c, const char *oarg, int oint, void *data)

 static int rpm_pcall(lua_State *L, int nargs, int nresults, int errfunc)

 {

     pid_t pid = getpid();

-    int status;

     int rc = lua_pcall(L, nargs, nresults, errfunc);

     /* Terminate unhandled fork from Lua script */

-    if (pid != getpid())

-	_exit(1);

-

-    if (waitpid(0, &status, WNOHANG) == 0) {

-	rpmlog(RPMLOG_WARNING,

-		_("runaway fork() in Lua script\n"));

+    if (pid != getpid()) {

+	rpmlog(RPMLOG_WARNING, _("runaway fork() in Lua script\n"));

+	_exit(EXIT_FAILURE);

     }

     return rc;

diff --git a/tests/rpmmacro.at b/tests/rpmmacro.at

index 0ebcc050c..47a13ef2b 100644

--- a/tests/rpmmacro.at

+++ b/tests/rpmmacro.at

@@ -1322,13 +1322,12 @@ nil	No such file or directory	2.0

 ],

 [])

-# This uses io.stderr:write() because the grue from the previous test 

-# appears to have eaten stdout of the forked child, or something.

 RPMTEST_CHECK([

-runroot_other rpmlua -e 'pid = posix.fork(); if pid == 0 then a,b,c=rpm.redirect2null(-1); io.stderr:write(string.format("%s\t%s\t%s\n", a,b,c)) else posix.wait(pid) end'

+runroot_other rpmlua -e 'pid = posix.fork(); if pid == 0 then a,b,c=rpm.redirect2null(-1); print(string.format("%s\t%s\t%s", a,b,c)); io.flush() else posix.wait(pid) end'

 ],

 [0],

-[],

 [nil	Bad file descriptor	9.0

-])

+],

+[warning: runaway fork() in Lua script]

+)

 RPMTEST_CLEANUP

-- 

2.43.0