Date: Sun, 08 Apr 2007 23:15:28 +0400 From: Eygene Ryabinkin <rea-fbsd@codelabs.ru> To: FreeBSD-gnats-submit@FreeBSD.org Cc: fjoe@FreeBSD.org, harti@FreeBSD.org Subject: bin/111387: prevent infinite loops for make's "Remaking Makefiles" feature Message-ID: <E1HacrI-0003q5-Fi@pobox.codelabs.ru> Resent-Message-ID: <200704081920.l38JK2Al060216@freefall.freebsd.org>
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>Number: 111387 >Category: bin >Synopsis: prevent infinite loops for make's "Remaking Makefiles" feature >Confidential: no >Severity: critical >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sun Apr 08 19:20:01 GMT 2007 >Closed-Date: >Last-Modified: >Originator: Eygene Ryabinkin >Release: FreeBSD 7.0-CURRENT i386 >Organization: Code Labs >Environment: System: FreeBSD XXX 7.0-CURRENT FreeBSD 7.0-CURRENT #10: Sat Mar 31 16:23:39 MSD 2007 root@XXX:/usr/obj/usr/src/sys/XXX i386 >Description: After the new make's "Remaking Makefiles" feature was introduced I started to see the ports that were unable to build properly and make was terminating with the "Max recursion level (500) exceeded". The investigation showed that the problem was in the Makefile targets that were considered out-of-date and had some rules to build them, but the actual rules were not touching the target in any way. >How-To-Repeat: The following shell script will show the essence of the problem. --- create-test.sh begins here --- #!/bin/sh echo -n "Creating test files: Makefile and Makefile.in..." cat > Makefile << "EOF" all: Makefile Makefile: Makefile.in echo "Wow, wow! I am the dummy target." EOF touch Makefile sleep 2 touch Makefile.in echo "OK" echo echo "OK, spawning 'make'" make --- create-test.sh ends here --- Additionally, you can try to build the mail/mutt-ng port on the 7-CURRENT using the tree with src/usr.bin/make/main.c >= 1.161 (other parts of the "Remaking Makefiles" feature should be present too, but if you have the consistent tree with the aforementioned main.c -- you got the buggy code). >Fix: I've been straight: just make two 'stat' calls before and after the Makefile build and compare the whole 'struct stat' contents. If something has changed -- we're considering the target to be really rebuilt and will try to restart make. This helped me to overcome the trouble with my simple example as well as to build the mail/mutt-ng and the recent development version of cURL that had this issue too. The patch is below. --- main.c.patch begins here --- --- usr.bin/make/main.c.orig Sun Apr 8 22:13:46 2007 +++ usr.bin/make/main.c Sun Apr 8 22:42:52 2007 @@ -62,6 +62,7 @@ */ #include <sys/param.h> +#include <sys/types.h> #include <sys/stat.h> #include <sys/sysctl.h> #include <sys/time.h> @@ -694,6 +695,7 @@ LstNode *ln; int error_cnt = 0; int remade_cnt = 0; + struct stat pre_sb, post_sb; Compat_InstallSignalHandlers(); @@ -767,7 +769,11 @@ /* * Check and remake the makefile */ + if (stat(gn->name, &pre_sb) != 0) + memset(&pre_sb, 0, sizeof(pre_sb)); Compat_Make(gn, gn); + if (stat(gn->name, &post_sb) != 0) + memset(&post_sb, 0, sizeof(post_sb)); /* * Restore -t, -q and -n behaviour @@ -784,8 +790,20 @@ * ERROR An error occurred while gn was being created * ABORTED gn was not remade because one of its inferiors * could not be made due to errors. + * + * We are checking if file's 'struct stat' was changed, + * since we do not want to restart the process if there + * were some makefile(s) that was not actually remade -- + * this can cause loops. The simplest example is: + * ----- + * Makefile: Makefile.in + * echo "Yo, all is done, no need to worry." + * ----- + * and the Makefile is out-of-date. */ - if (gn->made == MADE) + if (gn->made == MADE && + memcmp((const void*)&pre_sb, (const void*)&post_sb, + sizeof(pre_sb)) != 0) remade_cnt++; else if (gn->made == ERROR) error_cnt++; --- main.c.patch ends here --- >Release-Note: >Audit-Trail: >Unformatted:
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