From patchwork Thu Apr 30 12:05:35 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gary Benson X-Patchwork-Id: 6503 Received: (qmail 80246 invoked by alias); 30 Apr 2015 12:06:00 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 80179 invoked by uid 89); 30 Apr 2015 12:05:59 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.1 required=5.0 tests=AWL, BAYES_00, SPF_HELO_PASS, SPF_PASS, T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Thu, 30 Apr 2015 12:05:51 +0000 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 4B8C72BB382; Thu, 30 Apr 2015 12:05:50 +0000 (UTC) Received: from blade.nx (ovpn-116-76.ams2.redhat.com [10.36.116.76]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t3UC5m1L021308; Thu, 30 Apr 2015 08:05:48 -0400 Received: from blade.nx (localhost [127.0.0.1]) by blade.nx (Postfix) with ESMTP id 84369263E66; Thu, 30 Apr 2015 13:05:47 +0100 (BST) From: Gary Benson To: gdb-patches@sourceware.org Cc: Eli Zaretskii , Pedro Alves , Doug Evans , =?UTF-8?q?Iago=20L=C3=B3pez=20Galeiras?= Subject: [PATCH 2/9 v2] Introduce nat/linux-namespaces.[ch] Date: Thu, 30 Apr 2015 13:05:35 +0100 Message-Id: <1430395542-16017-3-git-send-email-gbenson@redhat.com> In-Reply-To: <1429186791-6867-1-git-send-email-gbenson@redhat.com> References: <1429186791-6867-1-git-send-email-gbenson@redhat.com> X-IsSubscribed: yes This commit introduces new shared files nat/linux-namespaces.[ch] containing code to support Linux namespaces that will be used by both GDB and gdbserver. gdb/ChangeLog: * configure.ac (AC_CHECK_FUNCS): Add setns. * config.in: Regenerate. * configure: Likewise. * nat/linux-namespaces.h: New file. * nat/linux-namespaces.c: Likewise. * Makefile.in (HFILES_NO_SRCDIR): Add nat/linux-namespaces.h. (linux-namespaces.o): New rule. * config/aarch64/linux.mh (NATDEPFILES): Add linux-namespaces.o. * config/alpha/alpha-linux.mh (NATDEPFILES): Likewise. * config/arm/linux.mh (NATDEPFILES): Likewise. * config/i386/linux.mh (NATDEPFILES): Likewise. * config/i386/linux64.mh (NATDEPFILES): Likewise. * config/ia64/linux.mh (NATDEPFILES): Likewise. * config/m32r/linux.mh (NATDEPFILES): Likewise. * config/m68k/linux.mh (NATDEPFILES): Likewise. * config/mips/linux.mh (NATDEPFILES): Likewise. * config/pa/linux.mh (NATDEPFILES): Likewise. * config/powerpc/linux.mh (NATDEPFILES): Likewise. * config/powerpc/ppc64-linux.mh (NATDEPFILES): Likewise. * config/powerpc/spu-linux.mh (NATDEPFILES): Likewise. * config/s390/linux.mh (NATDEPFILES): Likewise. * config/sparc/linux.mh (NATDEPFILES): Likewise. * config/sparc/linux64.mh (NATDEPFILES): Likewise. * config/tilegx/linux.mh (NATDEPFILES): Likewise. * config/xtensa/linux.mh (NATDEPFILES): Likewise. gdb/gdbserver/ChangeLog: * configure.ac (AC_CHECK_FUNCS): Add setns. * config.in: Regenerate. * configure: Likewise. * Makefile.in (SFILES): Add nat/linux-namespaces.c. (linux-namespaces.o): New rule. * configure.srv (srv_linux_obj): Add linux-namespaces.o. --- gdb/ChangeLog | 28 + gdb/Makefile.in | 6 +- gdb/config.in | 3 + gdb/config/aarch64/linux.mh | 2 +- gdb/config/alpha/alpha-linux.mh | 2 +- gdb/config/arm/linux.mh | 2 +- gdb/config/i386/linux.mh | 2 +- gdb/config/i386/linux64.mh | 2 +- gdb/config/ia64/linux.mh | 3 +- gdb/config/m32r/linux.mh | 2 +- gdb/config/m68k/linux.mh | 2 +- gdb/config/mips/linux.mh | 2 +- gdb/config/pa/linux.mh | 2 +- gdb/config/powerpc/linux.mh | 2 +- gdb/config/powerpc/ppc64-linux.mh | 3 +- gdb/config/powerpc/spu-linux.mh | 4 +- gdb/config/s390/linux.mh | 2 +- gdb/config/sparc/linux.mh | 2 +- gdb/config/sparc/linux64.mh | 2 +- gdb/config/tilegx/linux.mh | 2 +- gdb/config/xtensa/linux.mh | 2 +- gdb/configure | 2 +- gdb/configure.ac | 2 +- gdb/gdbserver/ChangeLog | 9 + gdb/gdbserver/Makefile.in | 6 +- gdb/gdbserver/config.in | 3 + gdb/gdbserver/configure | 2 +- gdb/gdbserver/configure.ac | 2 +- gdb/gdbserver/configure.srv | 2 +- gdb/nat/linux-namespaces.c | 1042 +++++++++++++++++++++++++++++++++++++ gdb/nat/linux-namespaces.h | 76 +++ 31 files changed, 1197 insertions(+), 26 deletions(-) create mode 100644 gdb/nat/linux-namespaces.c create mode 100644 gdb/nat/linux-namespaces.h diff --git a/gdb/Makefile.in b/gdb/Makefile.in index 47b216a..9921dcb 100644 --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -980,7 +980,7 @@ common/common-debug.h common/cleanups.h common/gdb_setjmp.h \ common/common-exceptions.h target/target.h common/symbol.h \ common/common-regcache.h fbsd-tdep.h nat/linux-personality.h \ common/fileio.h nat/x86-linux.h nat/x86-linux-dregs.h \ -common/cleanup-utils.h +common/cleanup-utils.h nat/linux-namespaces.h # Header files that already have srcdir in them, or which are in objdir. @@ -2325,6 +2325,10 @@ x86-linux-dregs.o: ${srcdir}/nat/x86-linux-dregs.c $(COMPILE) $(srcdir)/nat/x86-linux-dregs.c $(POSTCOMPILE) +linux-namespaces.o: ${srcdir}/nat/linux-namespaces.c + $(COMPILE) $(srcdir)/nat/linux-namespaces.c + $(POSTCOMPILE) + # # gdb/tui/ dependencies # diff --git a/gdb/config.in b/gdb/config.in index d41e6cf..5b6dbbb 100644 --- a/gdb/config.in +++ b/gdb/config.in @@ -390,6 +390,9 @@ /* Define to 1 if you have the `setlocale' function. */ #undef HAVE_SETLOCALE +/* Define to 1 if you have the `setns' function. */ +#undef HAVE_SETNS + /* Define to 1 if you have the `setpgid' function. */ #undef HAVE_SETPGID diff --git a/gdb/config/aarch64/linux.mh b/gdb/config/aarch64/linux.mh index 7f96e4d..6a8aa7d 100644 --- a/gdb/config/aarch64/linux.mh +++ b/gdb/config/aarch64/linux.mh @@ -22,7 +22,7 @@ NAT_FILE= config/nm-linux.h NATDEPFILES= inf-ptrace.o fork-child.o aarch64-linux-nat.o \ proc-service.o linux-thread-db.o linux-nat.o linux-fork.o \ linux-procfs.o linux-ptrace.o linux-osdata.o linux-waitpid.o \ - linux-personality.o + linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES= -ldl $(RDYNAMIC) diff --git a/gdb/config/alpha/alpha-linux.mh b/gdb/config/alpha/alpha-linux.mh index 2ea02a1..4991dd2 100644 --- a/gdb/config/alpha/alpha-linux.mh +++ b/gdb/config/alpha/alpha-linux.mh @@ -3,7 +3,7 @@ NAT_FILE= config/nm-linux.h NATDEPFILES= inf-ptrace.o alpha-linux-nat.o \ fork-child.o proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ - linux-waitpid.o linux-personality.o + linux-waitpid.o linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list # The dynamically loaded libthread_db needs access to symbols in the diff --git a/gdb/config/arm/linux.mh b/gdb/config/arm/linux.mh index 549bf42..f0c5967 100644 --- a/gdb/config/arm/linux.mh +++ b/gdb/config/arm/linux.mh @@ -4,7 +4,7 @@ NAT_FILE= config/nm-linux.h NATDEPFILES= inf-ptrace.o fork-child.o arm-linux-nat.o \ proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ - linux-waitpid.o linux-personality.o + linux-waitpid.o linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES= -ldl $(RDYNAMIC) diff --git a/gdb/config/i386/linux.mh b/gdb/config/i386/linux.mh index 9be2c5f..421c56f 100644 --- a/gdb/config/i386/linux.mh +++ b/gdb/config/i386/linux.mh @@ -6,7 +6,7 @@ NATDEPFILES= inf-ptrace.o fork-child.o \ proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ linux-btrace.o linux-waitpid.o linux-personality.o x86-linux.o \ - x86-linux-dregs.o + x86-linux-dregs.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list # The dynamically loaded libthread_db needs access to symbols in the diff --git a/gdb/config/i386/linux64.mh b/gdb/config/i386/linux64.mh index 224a2a9..04cbb95 100644 --- a/gdb/config/i386/linux64.mh +++ b/gdb/config/i386/linux64.mh @@ -6,7 +6,7 @@ NATDEPFILES= inf-ptrace.o fork-child.o \ proc-service.o linux-thread-db.o linux-fork.o \ linux-procfs.o linux-ptrace.o linux-btrace.o \ linux-waitpid.o linux-personality.o x86-linux.o \ - x86-linux-dregs.o + x86-linux-dregs.o linux-namespaces.o NAT_FILE= config/nm-linux.h NAT_CDEPS = $(srcdir)/proc-service.list diff --git a/gdb/config/ia64/linux.mh b/gdb/config/ia64/linux.mh index 9dce22b..b05f834 100644 --- a/gdb/config/ia64/linux.mh +++ b/gdb/config/ia64/linux.mh @@ -6,7 +6,8 @@ NATDEPFILES= inf-ptrace.o fork-child.o \ proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o \ linux-personality.o \ - linux-procfs.o linux-ptrace.o linux-waitpid.o + linux-procfs.o linux-ptrace.o linux-waitpid.o \ + linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES = -ldl $(RDYNAMIC) diff --git a/gdb/config/m32r/linux.mh b/gdb/config/m32r/linux.mh index 6b810e6..277d8bd 100644 --- a/gdb/config/m32r/linux.mh +++ b/gdb/config/m32r/linux.mh @@ -4,7 +4,7 @@ NAT_FILE= config/nm-linux.h NATDEPFILES= inf-ptrace.o fork-child.o \ m32r-linux-nat.o proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ - linux-waitpid.o linux-personality.o + linux-waitpid.o linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES= -ldl $(RDYNAMIC) diff --git a/gdb/config/m68k/linux.mh b/gdb/config/m68k/linux.mh index f3b3baa..60d5ce4 100644 --- a/gdb/config/m68k/linux.mh +++ b/gdb/config/m68k/linux.mh @@ -6,7 +6,7 @@ NATDEPFILES= inf-ptrace.o fork-child.o \ proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ linux-personality.o \ - linux-waitpid.o + linux-waitpid.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list # The dynamically loaded libthread_db needs access to symbols in the diff --git a/gdb/config/mips/linux.mh b/gdb/config/mips/linux.mh index d6a802f..11ff903 100644 --- a/gdb/config/mips/linux.mh +++ b/gdb/config/mips/linux.mh @@ -5,7 +5,7 @@ NATDEPFILES= inf-ptrace.o fork-child.o mips-linux-nat.o \ linux-nat.o linux-osdata.o linux-fork.o \ linux-procfs.o linux-ptrace.o linux-waitpid.o \ linux-personality.o \ - mips-linux-watch.o + mips-linux-watch.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES = -ldl $(RDYNAMIC) diff --git a/gdb/config/pa/linux.mh b/gdb/config/pa/linux.mh index 9539b64..1b73ecd 100644 --- a/gdb/config/pa/linux.mh +++ b/gdb/config/pa/linux.mh @@ -4,7 +4,7 @@ NATDEPFILES= inf-ptrace.o fork-child.o \ hppa-linux-nat.o proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o \ linux-procfs.o linux-ptrace.o linux-waitpid.o \ - linux-personality.o + linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES = -ldl $(RDYNAMIC) diff --git a/gdb/config/powerpc/linux.mh b/gdb/config/powerpc/linux.mh index 76e62c0..f4a52c3 100644 --- a/gdb/config/powerpc/linux.mh +++ b/gdb/config/powerpc/linux.mh @@ -6,7 +6,7 @@ NAT_FILE= config/nm-linux.h NATDEPFILES= inf-ptrace.o fork-child.o \ ppc-linux-nat.o proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ - linux-waitpid.o linux-personality.o + linux-waitpid.o linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES = -ldl $(RDYNAMIC) diff --git a/gdb/config/powerpc/ppc64-linux.mh b/gdb/config/powerpc/ppc64-linux.mh index 7eb6507..580eb1f 100644 --- a/gdb/config/powerpc/ppc64-linux.mh +++ b/gdb/config/powerpc/ppc64-linux.mh @@ -6,7 +6,8 @@ NAT_FILE= config/nm-linux.h NATDEPFILES= inf-ptrace.o fork-child.o \ ppc-linux-nat.o proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ - linux-waitpid.o ppc-linux.o linux-personality.o + linux-waitpid.o ppc-linux.o linux-personality.o \ + linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list # The PowerPC has severe limitations on TOC size, and uses them even diff --git a/gdb/config/powerpc/spu-linux.mh b/gdb/config/powerpc/spu-linux.mh index d44aeeb..9205b62 100644 --- a/gdb/config/powerpc/spu-linux.mh +++ b/gdb/config/powerpc/spu-linux.mh @@ -4,5 +4,5 @@ # PPU side of the Cell BE and debugging the SPU side. NATDEPFILES = spu-linux-nat.o fork-child.o inf-ptrace.o \ - linux-procfs.o linux-ptrace.o linux-waitpid.o linux-personality.o - + linux-procfs.o linux-ptrace.o linux-waitpid.o \ + linux-personality.o linux-namespaces.o diff --git a/gdb/config/s390/linux.mh b/gdb/config/s390/linux.mh index e1ad899..4a137cd 100644 --- a/gdb/config/s390/linux.mh +++ b/gdb/config/s390/linux.mh @@ -4,6 +4,6 @@ NATDEPFILES= inf-ptrace.o fork-child.o s390-linux-nat.o \ linux-thread-db.o proc-service.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ linux-personality.o \ - linux-waitpid.o + linux-waitpid.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES = -ldl $(RDYNAMIC) diff --git a/gdb/config/sparc/linux.mh b/gdb/config/sparc/linux.mh index bd7fc86..385f640 100644 --- a/gdb/config/sparc/linux.mh +++ b/gdb/config/sparc/linux.mh @@ -5,7 +5,7 @@ NATDEPFILES= sparc-nat.o sparc-linux-nat.o \ proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o \ linux-procfs.o linux-ptrace.o linux-waitpid.o \ - linux-personality.o + linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list # The dynamically loaded libthread_db needs access to symbols in the diff --git a/gdb/config/sparc/linux64.mh b/gdb/config/sparc/linux64.mh index 86f984f..8df0de1 100644 --- a/gdb/config/sparc/linux64.mh +++ b/gdb/config/sparc/linux64.mh @@ -5,7 +5,7 @@ NATDEPFILES= sparc-nat.o sparc64-nat.o sparc64-linux-nat.o \ proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o \ linux-procfs.o linux-ptrace.o linux-waitpid.o \ - linux-personality.o + linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list # The dynamically loaded libthread_db needs access to symbols in the diff --git a/gdb/config/tilegx/linux.mh b/gdb/config/tilegx/linux.mh index b5edcd4..ec648d3 100644 --- a/gdb/config/tilegx/linux.mh +++ b/gdb/config/tilegx/linux.mh @@ -6,7 +6,7 @@ NATDEPFILES= inf-ptrace.o fork-child.o \ proc-service.o linux-thread-db.o \ linux-nat.o linux-osdata.o linux-fork.o \ linux-procfs.o linux-ptrace.o linux-waitpid.o \ - linux-personality.o + linux-personality.o linux-namespaces.o # The dynamically loaded libthread_db needs access to symbols in the # gdb executable. diff --git a/gdb/config/xtensa/linux.mh b/gdb/config/xtensa/linux.mh index b4e59b3..d5b8f91 100644 --- a/gdb/config/xtensa/linux.mh +++ b/gdb/config/xtensa/linux.mh @@ -5,7 +5,7 @@ NAT_FILE= config/nm-linux.h NATDEPFILES= inf-ptrace.o fork-child.o xtensa-linux-nat.o \ linux-thread-db.o proc-service.o \ linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \ - linux-waitpid.o linux-personality.o + linux-waitpid.o linux-personality.o linux-namespaces.o NAT_CDEPS = $(srcdir)/proc-service.list LOADLIBES = -ldl $(RDYNAMIC) diff --git a/gdb/configure b/gdb/configure index 2baf6dd..5100921 100755 --- a/gdb/configure +++ b/gdb/configure @@ -10957,7 +10957,7 @@ for ac_func in getauxval getrusage getuid getgid \ sigaction sigprocmask sigsetmask socketpair \ ttrace wborder wresize setlocale iconvlist libiconvlist btowc \ setrlimit getrlimit posix_madvise waitpid \ - ptrace64 sigaltstack mkdtemp + ptrace64 sigaltstack mkdtemp setns do : as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh` ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var" diff --git a/gdb/configure.ac b/gdb/configure.ac index c703e35..2035a37 100644 --- a/gdb/configure.ac +++ b/gdb/configure.ac @@ -1331,7 +1331,7 @@ AC_CHECK_FUNCS([getauxval getrusage getuid getgid \ sigaction sigprocmask sigsetmask socketpair \ ttrace wborder wresize setlocale iconvlist libiconvlist btowc \ setrlimit getrlimit posix_madvise waitpid \ - ptrace64 sigaltstack mkdtemp]) + ptrace64 sigaltstack mkdtemp setns]) AM_LANGINFO_CODESET GDB_AC_COMMON diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in index 8ba88d4..4179cd6 100644 --- a/gdb/gdbserver/Makefile.in +++ b/gdb/gdbserver/Makefile.in @@ -180,7 +180,8 @@ SFILES= $(srcdir)/gdbreplay.c $(srcdir)/inferiors.c $(srcdir)/dll.c \ $(srcdir)/common/common-debug.c $(srcdir)/common/cleanups.c \ $(srcdir)/common/common-exceptions.c $(srcdir)/symbol.c \ $(srcdir)/common/btrace-common.c \ - $(srcdir)/common/fileio.c $(srcdir)/common/cleanup-utils.c + $(srcdir)/common/fileio.c $(srcdir)/common/cleanup-utils.c \ + $(srcdir)/nat/linux-namespaces.c DEPFILES = @GDBSERVER_DEPFILES@ @@ -619,6 +620,9 @@ x86-linux-dregs.o: ../nat/x86-linux-dregs.c cleanup-utils.o: ../common/cleanup-utils.c $(COMPILE) $< $(POSTCOMPILE) +linux-namespaces.o: ../nat/linux-namespaces.c + $(COMPILE) $< + $(POSTCOMPILE) aarch64.c : $(srcdir)/../regformats/aarch64.dat $(regdat_sh) $(SHELL) $(regdat_sh) $(srcdir)/../regformats/aarch64.dat aarch64.c diff --git a/gdb/gdbserver/config.in b/gdb/gdbserver/config.in index 3c3bfca..893aaab 100644 --- a/gdb/gdbserver/config.in +++ b/gdb/gdbserver/config.in @@ -183,6 +183,9 @@ /* Define to 1 if you have the `pwrite' function. */ #undef HAVE_PWRITE +/* Define to 1 if you have the `setns' function. */ +#undef HAVE_SETNS + /* Define to 1 if you have the header file. */ #undef HAVE_SGTTY_H diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure index 75860dd..bcb3f2e 100755 --- a/gdb/gdbserver/configure +++ b/gdb/gdbserver/configure @@ -5310,7 +5310,7 @@ fi done -for ac_func in getauxval pread pwrite pread64 +for ac_func in getauxval pread pwrite pread64 setns do : as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh` ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var" diff --git a/gdb/gdbserver/configure.ac b/gdb/gdbserver/configure.ac index 34af269..2aef2b4 100644 --- a/gdb/gdbserver/configure.ac +++ b/gdb/gdbserver/configure.ac @@ -94,7 +94,7 @@ AC_CHECK_HEADERS(sgtty.h termio.h termios.h sys/reg.h string.h dnl fcntl.h signal.h sys/file.h dnl sys/ioctl.h netinet/in.h sys/socket.h netdb.h dnl netinet/tcp.h arpa/inet.h) -AC_CHECK_FUNCS(getauxval pread pwrite pread64) +AC_CHECK_FUNCS(getauxval pread pwrite pread64 setns) GDB_AC_COMMON diff --git a/gdb/gdbserver/configure.srv b/gdb/gdbserver/configure.srv index 81dd235..7f89f2f 100644 --- a/gdb/gdbserver/configure.srv +++ b/gdb/gdbserver/configure.srv @@ -42,7 +42,7 @@ srv_amd64_linux_xmlfiles="i386/amd64-linux.xml i386/amd64-avx-linux.xml i386/amd # Linux object files. This is so we don't have to repeat # these files over and over again. -srv_linux_obj="linux-low.o linux-osdata.o linux-procfs.o linux-ptrace.o linux-waitpid.o linux-personality.o" +srv_linux_obj="linux-low.o linux-osdata.o linux-procfs.o linux-ptrace.o linux-waitpid.o linux-personality.o linux-namespaces.o" # Input is taken from the "${target}" variable. diff --git a/gdb/nat/linux-namespaces.c b/gdb/nat/linux-namespaces.c new file mode 100644 index 0000000..3603733 --- /dev/null +++ b/gdb/nat/linux-namespaces.c @@ -0,0 +1,1042 @@ +/* Linux namespaces(7) support. + + Copyright (C) 2015 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#include "common-defs.h" +#include "nat/linux-namespaces.h" +#include "filestuff.h" +#include +#include +#include +#include +#include +#include +#include +#include + +/* See nat/linux-namespaces.h. */ +int debug_linux_namespaces; + +/* Handle systems without setns. */ + +#ifndef HAVE_SETNS +static int +setns (int fd, int nstype) +{ +#ifdef __NR_setns + return syscall (__NR_setns, fd, nstype); +#else + errno = ENOSYS; + return -1; +#endif +} +#endif + +/* A Linux namespace. */ + +struct linux_ns +{ + /* Filename of this namespace's entries in /proc/PID/ns. */ + const char *filename; + + /* Nonzero if this object has been initialized. */ + int initialized; + + /* Nonzero if this namespace is supported on this system. */ + int supported; + + /* ID of the namespace the calling process is in, used to + see if other processes share the namespace. The code in + this file assumes that the calling process never changes + namespace. */ + ino_t id; +}; + +/* Return the absolute filename of process PID's /proc/PID/ns + entry for namespace NS. The returned value persists until + this function is next called. */ + +static const char * +linux_ns_filename (struct linux_ns *ns, int pid) +{ + static char filename[PATH_MAX]; + + gdb_assert (pid > 0); + xsnprintf (filename, sizeof (filename), "/proc/%d/ns/%s", pid, + ns->filename); + + return filename; +} + +/* Return a representation of the caller's TYPE namespace, or + NULL if TYPE namespaces are not supported on this system. */ + +static struct linux_ns * +linux_ns_get_namespace (enum linux_ns_type type) +{ + static struct linux_ns namespaces[NUM_LINUX_NS_TYPES] = + { + { "ipc" }, + { "mnt" }, + { "net" }, + { "pid" }, + { "user" }, + { "uts" }, + }; + struct linux_ns *ns; + + gdb_assert (type >= 0 && type < NUM_LINUX_NS_TYPES); + ns = &namespaces[type]; + + if (!ns->initialized) + { + struct stat sb; + + if (stat (linux_ns_filename (ns, getpid ()), &sb) == 0) + { + ns->id = sb.st_ino; + + ns->supported = 1; + } + + ns->initialized = 1; + } + + return ns->supported ? ns : NULL; +} + +/* See nat/linux-namespaces.h. */ + +int +linux_ns_same (pid_t pid, enum linux_ns_type type) +{ + struct linux_ns *ns = linux_ns_get_namespace (type); + const char *filename; + struct stat sb; + + /* If the kernel does not support TYPE namespaces then there's + effectively only one TYPE namespace that all processes on + the system share. */ + if (ns == NULL) + return 1; + + /* Stat PID's TYPE namespace entry to get the namespace ID. This + might fail if the process died, or if we don't have the right + permissions (though we should be attached by this time so this + seems unlikely). In any event, we can't make any decisions and + must throw. */ + filename = linux_ns_filename (ns, pid); + if (stat (filename, &sb) != 0) + perror_with_name (filename); + + return sb.st_ino == ns->id; +} + +/* We need to use setns(2) to handle filesystem access in mount + namespaces other than our own, but this isn't permitted for + multithreaded processes. GDB is multithreaded when compiled + with Guile support, and may become multithreaded if compiled + with Python support. We deal with this by spawning a single- + threaded helper process to access mount namespaces other than + our own. + + The helper process is started the first time a call to setns + is required. The main process (GDB or gdbserver) communicates + with the helper via sockets, passing file descriptors where + necessary using SCM_RIGHTS. Once started the helper process + runs until the main process terminates; when this happens the + helper will receive socket errors, notice that its parent died, + and exit accordingly (see mnsh_maybe_mourn_peer). + + The protocol is that the main process sends a request in a + single message, and the helper replies to every message it + receives with a single-message response. If the helper + receives a message it does not understand it will reply with + a MNSH_MSG_ERROR message. The main process checks all + responses it receives with gdb_assert, so if the main process + receives something unexpected (which includes MNSH_MSG_ERROR) + the main process will call internal_error. + + For avoidance of doubt, if the helper process receives a + message it doesn't handle it will reply with MNSH_MSG_ERROR. + If the main process receives MNSH_MSG_ERROR at any time then + it will call internal_error. If internal_error causes the + main process to exit, the helper will notice this and also + exit. The helper will not exit until the main process + terminates, so if the user continues through internal_error + the helper will still be there awaiting requests from the + main process. + + Messages in both directions have the following payload: + + - TYPE (enum mnsh_msg_type, always sent) - the message type. + - INT1 and + - INT2 (int, always sent, though not always used) - two + values whose meaning is message-type-dependent. + See enum mnsh_msg_type documentation below. + - FD (int, optional, sent using SCM_RIGHTS) - an open file + descriptor. + - BUF (unstructured data, optional) - some data with message- + type-dependent meaning. + + Note that the helper process is the child of a call to fork, + so all code in the helper must be async-signal-safe. */ + +/* Mount namespace helper message types. */ + +enum mnsh_msg_type + { + /* An unrecoverable communication error occurred. + Receipt of this message by either end will cause + an assertion failure in the main process. */ + MNSH_MSG_ERROR, + + /* Requests, sent from the main process to the helper. */ + + /* A request that the helper call setns. Arguments should + be passed in FD and INT1. Helper should respond with a + MNSH_RET_INT. */ + MNSH_REQ_SETNS, + + /* A request that the helper call open. Arguments should + be passed in BUF, INT1 and INT2. The filename (in BUF) + should include a terminating NUL character. The helper + should respond with a MNSH_RET_FD. */ + MNSH_REQ_OPEN, + + /* A request that the helper call unlink. The single + argument (the filename) should be passed in BUF, and + should include a terminating NUL character. Helper + should respond with a MNSH_RET_INT. */ + MNSH_REQ_UNLINK, + + /* A request that the helper call readlink. The single + argument (the filename) should be passed in BUF, and + should include a terminating NUL character. The helper + should respond with a MNSH_RET_INTSTR. */ + MNSH_REQ_READLINK, + + /* Responses, sent to the main process from the helper. */ + + /* Return an integer in INT1 and errno in INT2. */ + MNSH_RET_INT, + + /* Return a file descriptor in FD if one was opened or an + integer in INT1 otherwise. Return errno in INT2. */ + MNSH_RET_FD, + + /* Return an integer in INT1, errno in INT2, and optionally + some data in BUF. */ + MNSH_RET_INTSTR, + }; + +/* Print a string representation of a message using debug_printf. + This function is not async-signal-safe so should never be + called from the helper. */ + +static void +mnsh_debug_print_message (enum mnsh_msg_type type, + int fd, int int1, int int2, + const void *buf, int bufsiz) +{ + gdb_byte *c = (gdb_byte *) buf; + gdb_byte *cl = c + bufsiz; + + switch (type) + { + case MNSH_MSG_ERROR: + debug_printf ("ERROR"); + break; + + case MNSH_REQ_SETNS: + debug_printf ("SETNS"); + break; + + case MNSH_REQ_OPEN: + debug_printf ("OPEN"); + break; + + case MNSH_REQ_UNLINK: + debug_printf ("UNLINK"); + break; + + case MNSH_REQ_READLINK: + debug_printf ("READLINK"); + break; + + case MNSH_RET_INT: + debug_printf ("INT"); + break; + + case MNSH_RET_FD: + debug_printf ("FD"); + break; + + case MNSH_RET_INTSTR: + debug_printf ("INTSTR"); + break; + + default: + debug_printf ("unknown-packet-%d", type); + } + + debug_printf (" %d %d %d \"", fd, int1, int2); + + for (; c < cl; c++) + debug_printf (*c >= ' ' && *c <= '~' ? "%c" : "\\%o", *c); + + debug_printf ("\""); +} + +/* Forward declaration. */ + +static void mnsh_maybe_mourn_peer (void); + +/* Send a message. The argument SOCK is the file descriptor of the + sending socket, the other arguments are the payload to send. + Return the number of bytes sent on success. Return -1 on failure + and set errno appropriately. This function is called by both the + main process and the helper so must be async-signal-safe. */ + +static ssize_t +mnsh_send_message (int sock, enum mnsh_msg_type type, + int fd, int int1, int int2, + const void *buf, int bufsiz) +{ + struct msghdr msg; + struct iovec iov[4]; + char fdbuf[CMSG_SPACE (sizeof (fd))]; + ssize_t size; + + /* Build the basic TYPE, INT1, INT2 message. */ + memset (&msg, 0, sizeof (msg)); + msg.msg_iov = iov; + + iov[0].iov_base = &type; + iov[0].iov_len = sizeof (type); + iov[1].iov_base = &int1; + iov[1].iov_len = sizeof (int1); + iov[2].iov_base = &int2; + iov[2].iov_len = sizeof (int2); + + msg.msg_iovlen = 3; + + /* Append BUF if supplied. */ + if (buf != NULL && bufsiz > 0) + { + iov[3].iov_base = alloca (bufsiz); + memcpy (iov[3].iov_base, buf, bufsiz); + iov[3].iov_len = bufsiz; + + msg.msg_iovlen ++; + } + + /* Attach FD if supplied. */ + if (fd >= 0) + { + struct cmsghdr *cmsg; + + msg.msg_control = fdbuf; + msg.msg_controllen = sizeof (fdbuf); + + cmsg = CMSG_FIRSTHDR (&msg); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + cmsg->cmsg_len = CMSG_LEN (sizeof (int)); + + *((int *) CMSG_DATA (cmsg)) = fd; + + msg.msg_controllen = cmsg->cmsg_len; + } + + /* Send the message. */ + size = sendmsg (sock, &msg, 0); + + if (size < 0) + mnsh_maybe_mourn_peer (); + + if (debug_linux_namespaces) + { + debug_printf ("mnsh: send: "); + mnsh_debug_print_message (type, fd, int1, int2, buf, bufsiz); + debug_printf (" -> %ld\n", size); + } + + return size; +} + +/* Receive a message. The argument SOCK is the file descriptor of + the receiving socket, the other arguments point to storage for + the received payload. Returns the number of bytes stored into + BUF on success, which may be zero in the event no BUF was sent. + Return -1 on failure and set errno appropriately. This function + is called from both the main process and the helper and must be + async-signal-safe. */ + +static ssize_t +mnsh_recv_message (int sock, enum mnsh_msg_type *type, + int *fd, int *int1, int *int2, + void *buf, int bufsiz) +{ + struct msghdr msg; + struct iovec iov[4]; + char fdbuf[CMSG_SPACE (sizeof (*fd))]; + struct cmsghdr *cmsg; + ssize_t size, fixed_size; + int i; + + /* Build the message to receive data into. */ + memset (&msg, 0, sizeof (msg)); + msg.msg_iov = iov; + + iov[0].iov_base = type; + iov[0].iov_len = sizeof (*type); + iov[1].iov_base = int1; + iov[1].iov_len = sizeof (*int1); + iov[2].iov_base = int2; + iov[2].iov_len = sizeof (*int2); + iov[3].iov_base = buf; + iov[3].iov_len = bufsiz; + + msg.msg_iovlen = 4; + + for (fixed_size = i = 0; i < msg.msg_iovlen - 1; i++) + fixed_size += iov[i].iov_len; + + msg.msg_control = fdbuf; + msg.msg_controllen = sizeof (fdbuf); + + /* Receive the message. */ + size = recvmsg (sock, &msg, MSG_CMSG_CLOEXEC); + if (size < 0) + { + if (debug_linux_namespaces) + debug_printf ("namespace-helper: recv failed (%ld)\n", size); + + mnsh_maybe_mourn_peer (); + + return size; + } + + /* Check for truncation. */ + if (size < fixed_size || (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) + { + if (debug_linux_namespaces) + debug_printf ("namespace-helper: recv truncated (%ld 0x%x)\n", + size, msg.msg_flags); + + mnsh_maybe_mourn_peer (); + + errno = EBADMSG; + return -1; + } + + /* Unpack the file descriptor if supplied. */ + cmsg = CMSG_FIRSTHDR (&msg); + if (cmsg != NULL + && cmsg->cmsg_len == CMSG_LEN (sizeof (int)) + && cmsg->cmsg_level == SOL_SOCKET + && cmsg->cmsg_type == SCM_RIGHTS) + *fd = *((int *) CMSG_DATA (cmsg)); + else + *fd = -1; + + if (debug_linux_namespaces) + { + debug_printf ("mnsh: recv: "); + mnsh_debug_print_message (*type, *fd, *int1, *int2, buf, + size - fixed_size); + debug_printf ("\n"); + } + + /* Return the number of bytes of data in BUF. */ + return size - fixed_size; +} + +/* Shortcuts for returning results from the helper. */ + +#define mnsh_return_int(sock, result, error) \ + mnsh_send_message (sock, MNSH_RET_INT, -1, result, error, NULL, 0) + +#define mnsh_return_fd(sock, fd, error) \ + mnsh_send_message (sock, MNSH_RET_FD, \ + (fd) < 0 ? -1 : (fd), \ + (fd) < 0 ? (fd) : 0, \ + error, NULL, 0) + +#define mnsh_return_intstr(sock, result, buf, bufsiz, error) \ + mnsh_send_message (sock, MNSH_RET_INTSTR, -1, result, error, \ + buf, bufsiz) + +/* Handle a MNSH_REQ_SETNS message. Must be async-signal-safe. */ + +static ssize_t +mnsh_handle_setns (int sock, int fd, int nstype) +{ + int result = setns (fd, nstype); + + return mnsh_return_int (sock, result, errno); +} + +/* Handle a MNSH_REQ_OPEN message. Must be async-signal-safe. */ + +static ssize_t +mnsh_handle_open (int sock, const char *filename, + int flags, mode_t mode) +{ + int fd = gdb_open_cloexec (filename, flags, mode); + ssize_t result = mnsh_return_fd (sock, fd, errno); + + if (fd >= 0) + close (fd); + + return result; +} + +/* Handle a MNSH_REQ_UNLINK message. Must be async-signal-safe. */ + +static ssize_t +mnsh_handle_unlink (int sock, const char *filename) +{ + int result = unlink (filename); + + return mnsh_return_int (sock, result, errno); +} + +/* Handle a MNSH_REQ_READLINK message. Must be async-signal-safe. */ + +static ssize_t +mnsh_handle_readlink (int sock, const char *filename) +{ + char buf[PATH_MAX]; + int len = readlink (filename, buf, sizeof (buf)); + + return mnsh_return_intstr (sock, len, + buf, len < 0 ? 0 : len, + errno); +} + +/* The helper process. Never returns. Must be async-signal-safe. */ + +static void mnsh_main (int sock) ATTRIBUTE_NORETURN; + +static void +mnsh_main (int sock) +{ + while (1) + { + enum mnsh_msg_type type; + int fd, int1, int2; + char buf[PATH_MAX]; + ssize_t size, response = -1; + + size = mnsh_recv_message (sock, &type, + &fd, &int1, &int2, + buf, sizeof (buf)); + + if (size >= 0 && size < sizeof (buf)) + { + switch (type) + { + case MNSH_REQ_SETNS: + if (fd > 0) + response = mnsh_handle_setns (sock, fd, int1); + break; + + case MNSH_REQ_OPEN: + if (buf[size - 1] == '\0') + response = mnsh_handle_open (sock, buf, int1, int2); + break; + + case MNSH_REQ_UNLINK: + if (buf[size - 1] == '\0') + response = mnsh_handle_unlink (sock, buf); + break; + + case MNSH_REQ_READLINK: + if (buf[size - 1] == '\0') + response = mnsh_handle_readlink (sock, buf); + break; + + default: + break; /* Handled below. */ + } + } + + /* Close any file descriptors we were passed. */ + if (fd >= 0) + close (fd); + + /* Can't handle this message, bounce it back. */ + if (response < 0) + { + if (size < 0) + size = 0; + + mnsh_send_message (sock, MNSH_MSG_ERROR, + -1, int1, int2, buf, size); + } + } +} + +/* The mount namespace helper process. */ + +struct linux_mnsh +{ + /* PID of helper. */ + pid_t pid; + + /* Socket for communication. */ + int sock; + + /* ID of the mount namespace the helper is currently in. */ + ino_t nsid; +}; + +/* In the helper process this is set to the PID of the process that + created the helper (i.e. GDB or gdbserver). In the main process + this is set to zero. Used by mnsh_maybe_mourn_peer. */ +static int mnsh_creator_pid = 0; + +/* Return an object representing the mount namespace helper process. + If no mount namespace helper process has been started then start + one. Return NULL if no mount namespace helper process could be + started. */ + +static struct linux_mnsh * +linux_mntns_get_helper (void) +{ + static struct linux_mnsh *helper = NULL; + + if (helper == NULL) + { + static struct linux_mnsh h; + struct linux_ns *ns; + pid_t helper_creator = getpid (); + int sv[2]; + + ns = linux_ns_get_namespace (LINUX_NS_MNT); + if (ns == NULL) + return NULL; + + if (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, sv) < 0) + return NULL; + + h.pid = fork (); + if (h.pid < 0) + { + int saved_errno = errno; + + close (sv[0]); + close (sv[1]); + + errno = saved_errno; + return NULL; + } + + if (h.pid == 0) + { + /* Child process. */ + close (sv[0]); + + mnsh_creator_pid = helper_creator; + + /* Debug printing isn't async-signal-safe. */ + debug_linux_namespaces = 0; + + mnsh_main (sv[1]); + } + + /* Parent process. */ + close (sv[1]); + + helper = &h; + helper->sock = sv[0]; + helper->nsid = ns->id; + + if (debug_linux_namespaces) + debug_printf ("Started mount namespace helper process %d\n", + helper->pid); + } + + return helper; +} + +/* Check whether the other process died and act accordingly. Called + whenever a socket error occurs, from both the main process and the + helper. Must be async-signal-safe when called from the helper. */ + +static void +mnsh_maybe_mourn_peer (void) +{ + if (mnsh_creator_pid != 0) + { + /* We're in the helper. Check if our current parent is the + process that started us. If it isn't, then our original + parent died and we've been reparented. Exit immediately + if that's the case. */ + if (getppid () != mnsh_creator_pid) + _exit (0); + } + else + { + /* We're in the main process. */ + + struct linux_mnsh *helper = linux_mntns_get_helper (); + int status; + pid_t pid; + + if (helper->pid < 0) + { + /* We already mourned it. */ + return; + } + + pid = waitpid (helper->pid, &status, WNOHANG); + if (pid == 0) + { + /* The helper is still alive. */ + return; + } + else if (pid == -1) + { + if (errno == ECHILD) + warning (_("mount namespace helper vanished?")); + else + internal_warning (__FILE__, __LINE__, + _("unhandled error %d"), errno); + } + else if (pid == helper->pid) + { + if (WIFEXITED (status)) + warning (_("mount namespace helper exited with status %d"), + WEXITSTATUS (status)); + else if (WIFSIGNALED (status)) + warning (_("mount namespace helper killed by signal %d"), + WTERMSIG (status)); + else + internal_warning (__FILE__, __LINE__, + _("unhandled status %d"), status); + } + else + internal_warning (__FILE__, __LINE__, + _("unknown pid %d"), pid); + + /* Something unrecoverable happened. */ + helper->pid = -1; + } +} + +/* Shortcuts for sending messages to the helper. */ + +#define mnsh_send_setns(helper, fd, nstype) \ + mnsh_send_message (helper->sock, MNSH_REQ_SETNS, fd, nstype, 0, \ + NULL, 0) + +#define mnsh_send_open(helper, filename, flags, mode) \ + mnsh_send_message (helper->sock, MNSH_REQ_OPEN, -1, flags, mode, \ + filename, strlen (filename) + 1) + +#define mnsh_send_unlink(helper, filename) \ + mnsh_send_message (helper->sock, MNSH_REQ_UNLINK, -1, 0, 0, \ + filename, strlen (filename) + 1) + +#define mnsh_send_readlink(helper, filename) \ + mnsh_send_message (helper->sock, MNSH_REQ_READLINK, -1, 0, 0, \ + filename, strlen (filename) + 1) + +/* Receive a message from the helper. Issue an assertion failure if + the message isn't a correctly-formatted MNSH_RET_INT. Set RESULT + and ERROR and return 0 on success. Set errno and return -1 on + failure. */ + +static int +mnsh_recv_int (struct linux_mnsh *helper, int *result, int *error) +{ + enum mnsh_msg_type type; + char buf[PATH_MAX]; + ssize_t size; + int fd; + + size = mnsh_recv_message (helper->sock, &type, &fd, + result, error, + buf, sizeof (buf)); + if (size < 0) + return -1; + + gdb_assert (type == MNSH_RET_INT); + gdb_assert (fd == -1); + gdb_assert (size == 0); + + return 0; +} + +/* Receive a message from the helper. Issue an assertion failure if + the message isn't a correctly-formatted MNSH_RET_FD. Set FD and + ERROR and return 0 on success. Set errno and return -1 on + failure. */ + +static int +mnsh_recv_fd (struct linux_mnsh *helper, int *fd, int *error) +{ + enum mnsh_msg_type type; + char buf[PATH_MAX]; + ssize_t size; + int result; + + size = mnsh_recv_message (helper->sock, &type, fd, + &result, error, + buf, sizeof (buf)); + if (size < 0) + return -1; + + gdb_assert (type == MNSH_RET_FD); + gdb_assert (size == 0); + + if (*fd < 0) + { + gdb_assert (result < 0); + *fd = result; + } + + return 0; +} + +/* Receive a message from the helper. Issue an assertion failure if + the message isn't a correctly-formatted MNSH_RET_INTSTR. Set + RESULT and ERROR and optionally store data in BUF, then return + the number of bytes stored in BUF on success (this may be zero). + Set errno and return -1 on error. */ + +static ssize_t +mnsh_recv_intstr (struct linux_mnsh *helper, + int *result, int *error, + void *buf, int bufsiz) +{ + enum mnsh_msg_type type; + ssize_t size; + int fd; + + size = mnsh_recv_message (helper->sock, &type, &fd, + result, error, + buf, bufsiz); + + if (size < 0) + return -1; + + gdb_assert (type == MNSH_RET_INTSTR); + gdb_assert (fd == -1); + + return size; +} + +/* Return values for linux_mntns_access_fs. */ + +enum mnsh_fs_code + { + /* Something went wrong, errno is set. */ + MNSH_FS_ERROR = -1, + + /* The main process is in the correct mount namespace. + The caller should access the filesystem directly. */ + MNSH_FS_DIRECT, + + /* The helper is in the correct mount namespace. + The caller should access the filesystem via the helper. */ + MNSH_FS_HELPER + }; + +/* Return a value indicating how the caller should access the + mount namespace of process PID. */ + +static enum mnsh_fs_code +linux_mntns_access_fs (pid_t pid) +{ + struct cleanup *old_chain; + struct linux_ns *ns; + struct stat sb; + struct linux_mnsh *helper; + ssize_t size; + int fd, saved_errno; + + if (pid == getpid ()) + return MNSH_FS_DIRECT; + + ns = linux_ns_get_namespace (LINUX_NS_MNT); + if (ns == NULL) + return MNSH_FS_DIRECT; + + old_chain = make_cleanup (null_cleanup, NULL); + + fd = gdb_open_cloexec (linux_ns_filename (ns, pid), O_RDONLY, 0); + if (fd < 0) + goto error; + + old_chain = make_cleanup_close (fd); + + if (fstat (fd, &sb) != 0) + goto error; + + if (sb.st_ino == ns->id) + { + do_cleanups (old_chain); + + return MNSH_FS_DIRECT; + } + + helper = linux_mntns_get_helper (); + if (helper == NULL) + goto error; + + if (sb.st_ino != helper->nsid) + { + int result, error; + + size = mnsh_send_setns (helper, fd, 0); + if (size < 0) + goto error; + + if (mnsh_recv_int (helper, &result, &error) != 0) + goto error; + + if (result != 0) + { + errno = error; + goto error; + } + + helper->nsid = sb.st_ino; + } + + do_cleanups (old_chain); + + return MNSH_FS_HELPER; + +error: + saved_errno = errno; + + do_cleanups (old_chain); + + errno = saved_errno; + return MNSH_FS_ERROR; +} + +/* See nat/linux-namespaces.h. */ + +int +linux_mntns_open_cloexec (pid_t pid, const char *filename, + int flags, mode_t mode) +{ + enum mnsh_fs_code access = linux_mntns_access_fs (pid); + struct linux_mnsh *helper; + int fd, error; + ssize_t size; + + if (access == MNSH_FS_ERROR) + return -1; + + if (access == MNSH_FS_DIRECT) + return gdb_open_cloexec (filename, flags, mode); + + gdb_assert (access == MNSH_FS_HELPER); + + helper = linux_mntns_get_helper (); + + size = mnsh_send_open (helper, filename, flags, mode); + if (size < 0) + return -1; + + if (mnsh_recv_fd (helper, &fd, &error) != 0) + return -1; + + if (fd < 0) + errno = error; + + return fd; +} + +/* See nat/linux-namespaces.h. */ + +int +linux_mntns_unlink (pid_t pid, const char *filename) +{ + enum mnsh_fs_code access = linux_mntns_access_fs (pid); + struct linux_mnsh *helper; + int ret, error; + ssize_t size; + + if (access == MNSH_FS_ERROR) + return -1; + + if (access == MNSH_FS_DIRECT) + return unlink (filename); + + gdb_assert (access == MNSH_FS_HELPER); + + helper = linux_mntns_get_helper (); + + size = mnsh_send_unlink (helper, filename); + if (size < 0) + return -1; + + if (mnsh_recv_int (helper, &ret, &error) != 0) + return -1; + + if (ret != 0) + errno = error; + + return ret; +} + +/* See nat/linux-namespaces.h. */ + +ssize_t +linux_mntns_readlink (pid_t pid, const char *filename, + char *buf, size_t bufsiz) +{ + enum mnsh_fs_code access = linux_mntns_access_fs (pid); + struct linux_mnsh *helper; + int ret, error; + ssize_t size; + + if (access == MNSH_FS_ERROR) + return -1; + + if (access == MNSH_FS_DIRECT) + return readlink (filename, buf, bufsiz); + + gdb_assert (access == MNSH_FS_HELPER); + + helper = linux_mntns_get_helper (); + + size = mnsh_send_readlink (helper, filename); + if (size < 0) + return -1; + + size = mnsh_recv_intstr (helper, &ret, &error, buf, bufsiz); + + if (size < 0) + { + ret = -1; + errno = error; + } + else + gdb_assert (size == ret); + + return ret; +} diff --git a/gdb/nat/linux-namespaces.h b/gdb/nat/linux-namespaces.h new file mode 100644 index 0000000..f9adc07 --- /dev/null +++ b/gdb/nat/linux-namespaces.h @@ -0,0 +1,76 @@ +/* Linux namespaces(7) support. + + Copyright (C) 2015 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#ifndef LINUX_NAMESPACES_H +#define LINUX_NAMESPACES_H + +/* Set to nonzero to enable debugging of Linux namespaces code. */ + +extern int debug_linux_namespaces; + +/* Enumeration of Linux namespace types. */ + +enum linux_ns_type + { + /* IPC namespace: System V IPC, POSIX message queues. */ + LINUX_NS_IPC, + + /* Mount namespace: mount points. */ + LINUX_NS_MNT, + + /* Network namespace: network devices, stacks, ports, etc. */ + LINUX_NS_NET, + + /* PID namespace: process IDs. */ + LINUX_NS_PID, + + /* User namespace: user and group IDs. */ + LINUX_NS_USER, + + /* UTS namespace: hostname and NIS domain name. */ + LINUX_NS_UTS, + + /* Number of Linux namespaces. */ + NUM_LINUX_NS_TYPES + }; + +/* Return nonzero if process PID has the same TYPE namespace as the + calling process, or if the kernel does not support TYPE namespaces + (in which case there is only one TYPE namespace). Return zero if + the kernel supports TYPE namespaces and the two processes have + different TYPE namespaces. */ + +extern int linux_ns_same (pid_t pid, enum linux_ns_type type); + +/* Like gdb_open_cloexec, but in the mount namespace of process + PID. */ + +extern int linux_mntns_open_cloexec (pid_t pid, const char *filename, + int flags, mode_t mode); + +/* Like unlink(2), but in the mount namespace of process PID. */ + +extern int linux_mntns_unlink (pid_t pid, const char *filename); + +/* Like readlink(2), but in the mount namespace of process PID. */ + +extern ssize_t linux_mntns_readlink (pid_t pid, const char *filename, + char *buf, size_t bufsiz); + +#endif /* LINUX_NAMESPACES_H */