From eb0edac83f82516bbbd5a0412bbdf7fd27c687f2 Mon Sep 17 00:00:00 2001 From: Gary Benson Date: Mon, 18 Jan 2016 09:45:10 +0000 Subject: [PATCH] Fix gdbserver build failure on targets without fork This commit fixes nat/linux-namespaces.c to build correctly on targets without fork. gdb/ChangeLog: * nat/linux-namespaces.c (do_fork): New function. (linux_mntns_get_helper): Use the above. gdb/gdbserver/ChangeLog: * configure.ac (AC_FUNC_FORK): New check. * config.in: Regenerate. * configure: Likewise. --- gdb/ChangeLog | 5 + gdb/gdbserver/ChangeLog | 6 + gdb/gdbserver/config.in | 21 +++ gdb/gdbserver/configure | 333 +++++++++++++++++++++++++++++++++++++-------- gdb/gdbserver/configure.ac | 1 + gdb/nat/linux-namespaces.c | 15 +- 6 files changed, 326 insertions(+), 55 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index dbc4b08..1603109 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2016-01-18 Gary Benson + + * nat/linux-namespaces.c (do_fork): New function. + (linux_mntns_get_helper): Use the above. + 2016-01-17 Jonas Hahnfeld (tiny change) Pushed by Joel Brobecker . diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index a76bb14..2311d03 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,9 @@ +2016-01-18 Gary Benson + + * configure.ac (AC_FUNC_FORK): New check. + * config.in: Regenerate. + * configure: Likewise. + 2016-01-14 Yao Qi * linux-aarch32-low.c (thumb2_breakpoint): Make it static. diff --git a/gdb/gdbserver/config.in b/gdb/gdbserver/config.in index e2566a9..2c3a69a 100644 --- a/gdb/gdbserver/config.in +++ b/gdb/gdbserver/config.in @@ -99,6 +99,9 @@ /* Define to 1 if you have the `fdwalk' function. */ #undef HAVE_FDWALK +/* Define to 1 if you have the `fork' function. */ +#undef HAVE_FORK + /* Define to 1 if you have the `getauxval' function. */ #undef HAVE_GETAUXVAL @@ -286,9 +289,21 @@ /* Define if UST is available */ #undef HAVE_UST +/* Define to 1 if you have the `vfork' function. */ +#undef HAVE_VFORK + +/* Define to 1 if you have the header file. */ +#undef HAVE_VFORK_H + /* Define to 1 if you have the header file. */ #undef HAVE_WAIT_H +/* Define to 1 if `fork' works. */ +#undef HAVE_WORKING_FORK + +/* Define to 1 if `vfork' works. */ +#undef HAVE_WORKING_VFORK + /* Define to the address where bug reports for this package should be sent. */ #undef PACKAGE_BUGREPORT @@ -393,3 +408,9 @@ /* Define to 1 if you need to in order for `stat' and other things to work. */ #undef _POSIX_SOURCE + +/* Define to `int' if does not define. */ +#undef pid_t + +/* Define as `fork' if `vfork' does not work. */ +#undef vfork diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure index 57af951..763c77d 100755 --- a/gdb/gdbserver/configure +++ b/gdb/gdbserver/configure @@ -1772,6 +1772,60 @@ fi } # ac_fn_c_try_link +# ac_fn_c_check_type LINENO TYPE VAR INCLUDES +# ------------------------------------------- +# Tests whether TYPE exists after having included INCLUDES, setting cache +# variable VAR accordingly. +ac_fn_c_check_type () +{ + as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5 +$as_echo_n "checking for $2... " >&6; } +if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then : + $as_echo_n "(cached) " >&6 +else + eval "$3=no" + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +$4 +int +main () +{ +if (sizeof ($2)) + return 0; + ; + return 0; +} +_ACEOF +if ac_fn_c_try_compile "$LINENO"; then : + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +$4 +int +main () +{ +if (sizeof (($2))) + return 0; + ; + return 0; +} +_ACEOF +if ac_fn_c_try_compile "$LINENO"; then : + +else + eval "$3=yes" +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext +fi +eval ac_res=\$$3 + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5 +$as_echo "$ac_res" >&6; } + eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;} + +} # ac_fn_c_check_type + # ac_fn_c_check_func LINENO FUNC VAR # ---------------------------------- # Tests whether FUNC exists, setting the cache variable VAR accordingly @@ -1929,60 +1983,6 @@ $as_echo "$ac_res" >&6; } } # ac_fn_cxx_check_decl -# ac_fn_c_check_type LINENO TYPE VAR INCLUDES -# ------------------------------------------- -# Tests whether TYPE exists after having included INCLUDES, setting cache -# variable VAR accordingly. -ac_fn_c_check_type () -{ - as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack - { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5 -$as_echo_n "checking for $2... " >&6; } -if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then : - $as_echo_n "(cached) " >&6 -else - eval "$3=no" - cat confdefs.h - <<_ACEOF >conftest.$ac_ext -/* end confdefs.h. */ -$4 -int -main () -{ -if (sizeof ($2)) - return 0; - ; - return 0; -} -_ACEOF -if ac_fn_c_try_compile "$LINENO"; then : - cat confdefs.h - <<_ACEOF >conftest.$ac_ext -/* end confdefs.h. */ -$4 -int -main () -{ -if (sizeof (($2))) - return 0; - ; - return 0; -} -_ACEOF -if ac_fn_c_try_compile "$LINENO"; then : - -else - eval "$3=yes" -fi -rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext -fi -rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext -fi -eval ac_res=\$$3 - { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5 -$as_echo "$ac_res" >&6; } - eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;} - -} # ac_fn_c_check_type - # ac_fn_c_compute_int LINENO EXPR VAR INCLUDES # -------------------------------------------- # Tries to find the compile-time value of EXPR in a program that includes @@ -5360,6 +5360,231 @@ fi done +ac_fn_c_check_type "$LINENO" "pid_t" "ac_cv_type_pid_t" "$ac_includes_default" +if test "x$ac_cv_type_pid_t" = x""yes; then : + +else + +cat >>confdefs.h <<_ACEOF +#define pid_t int +_ACEOF + +fi + +for ac_header in vfork.h +do : + ac_fn_c_check_header_mongrel "$LINENO" "vfork.h" "ac_cv_header_vfork_h" "$ac_includes_default" +if test "x$ac_cv_header_vfork_h" = x""yes; then : + cat >>confdefs.h <<_ACEOF +#define HAVE_VFORK_H 1 +_ACEOF + +fi + +done + +for ac_func in fork vfork +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" +eval as_val=\$$as_ac_var + if test "x$as_val" = x""yes; then : + cat >>confdefs.h <<_ACEOF +#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1 +_ACEOF + +fi +done + +if test "x$ac_cv_func_fork" = xyes; then + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for working fork" >&5 +$as_echo_n "checking for working fork... " >&6; } +if test "${ac_cv_func_fork_works+set}" = set; then : + $as_echo_n "(cached) " >&6 +else + if test "$cross_compiling" = yes; then : + ac_cv_func_fork_works=cross +else + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +$ac_includes_default +int +main () +{ + + /* By Ruediger Kuhlmann. */ + return fork () < 0; + + ; + return 0; +} +_ACEOF +if ac_fn_c_try_run "$LINENO"; then : + ac_cv_func_fork_works=yes +else + ac_cv_func_fork_works=no +fi +rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \ + conftest.$ac_objext conftest.beam conftest.$ac_ext +fi + +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_fork_works" >&5 +$as_echo "$ac_cv_func_fork_works" >&6; } + +else + ac_cv_func_fork_works=$ac_cv_func_fork +fi +if test "x$ac_cv_func_fork_works" = xcross; then + case $host in + *-*-amigaos* | *-*-msdosdjgpp*) + # Override, as these systems have only a dummy fork() stub + ac_cv_func_fork_works=no + ;; + *) + ac_cv_func_fork_works=yes + ;; + esac + { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: result $ac_cv_func_fork_works guessed because of cross compilation" >&5 +$as_echo "$as_me: WARNING: result $ac_cv_func_fork_works guessed because of cross compilation" >&2;} +fi +ac_cv_func_vfork_works=$ac_cv_func_vfork +if test "x$ac_cv_func_vfork" = xyes; then + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for working vfork" >&5 +$as_echo_n "checking for working vfork... " >&6; } +if test "${ac_cv_func_vfork_works+set}" = set; then : + $as_echo_n "(cached) " >&6 +else + if test "$cross_compiling" = yes; then : + ac_cv_func_vfork_works=cross +else + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +/* Thanks to Paul Eggert for this test. */ +$ac_includes_default +#include +#ifdef HAVE_VFORK_H +# include +#endif +/* On some sparc systems, changes by the child to local and incoming + argument registers are propagated back to the parent. The compiler + is told about this with #include , but some compilers + (e.g. gcc -O) don't grok . Test for this by using a + static variable whose address is put into a register that is + clobbered by the vfork. */ +static void +#ifdef __cplusplus +sparc_address_test (int arg) +# else +sparc_address_test (arg) int arg; +#endif +{ + static pid_t child; + if (!child) { + child = vfork (); + if (child < 0) { + perror ("vfork"); + _exit(2); + } + if (!child) { + arg = getpid(); + write(-1, "", 0); + _exit (arg); + } + } +} + +int +main () +{ + pid_t parent = getpid (); + pid_t child; + + sparc_address_test (0); + + child = vfork (); + + if (child == 0) { + /* Here is another test for sparc vfork register problems. This + test uses lots of local variables, at least as many local + variables as main has allocated so far including compiler + temporaries. 4 locals are enough for gcc 1.40.3 on a Solaris + 4.1.3 sparc, but we use 8 to be safe. A buggy compiler should + reuse the register of parent for one of the local variables, + since it will think that parent can't possibly be used any more + in this routine. Assigning to the local variable will thus + munge parent in the parent process. */ + pid_t + p = getpid(), p1 = getpid(), p2 = getpid(), p3 = getpid(), + p4 = getpid(), p5 = getpid(), p6 = getpid(), p7 = getpid(); + /* Convince the compiler that p..p7 are live; otherwise, it might + use the same hardware register for all 8 local variables. */ + if (p != p1 || p != p2 || p != p3 || p != p4 + || p != p5 || p != p6 || p != p7) + _exit(1); + + /* On some systems (e.g. IRIX 3.3), vfork doesn't separate parent + from child file descriptors. If the child closes a descriptor + before it execs or exits, this munges the parent's descriptor + as well. Test for this by closing stdout in the child. */ + _exit(close(fileno(stdout)) != 0); + } else { + int status; + struct stat st; + + while (wait(&status) != child) + ; + return ( + /* Was there some problem with vforking? */ + child < 0 + + /* Did the child fail? (This shouldn't happen.) */ + || status + + /* Did the vfork/compiler bug occur? */ + || parent != getpid() + + /* Did the file descriptor bug occur? */ + || fstat(fileno(stdout), &st) != 0 + ); + } +} +_ACEOF +if ac_fn_c_try_run "$LINENO"; then : + ac_cv_func_vfork_works=yes +else + ac_cv_func_vfork_works=no +fi +rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \ + conftest.$ac_objext conftest.beam conftest.$ac_ext +fi + +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_vfork_works" >&5 +$as_echo "$ac_cv_func_vfork_works" >&6; } + +fi; +if test "x$ac_cv_func_fork_works" = xcross; then + ac_cv_func_vfork_works=$ac_cv_func_vfork + { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: result $ac_cv_func_vfork_works guessed because of cross compilation" >&5 +$as_echo "$as_me: WARNING: result $ac_cv_func_vfork_works guessed because of cross compilation" >&2;} +fi + +if test "x$ac_cv_func_vfork_works" = xyes; then + +$as_echo "#define HAVE_WORKING_VFORK 1" >>confdefs.h + +else + +$as_echo "#define vfork fork" >>confdefs.h + +fi +if test "x$ac_cv_func_fork_works" = xyes; then + +$as_echo "#define HAVE_WORKING_FORK 1" >>confdefs.h + +fi + for ac_func in getauxval pread pwrite pread64 setns do : as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh` diff --git a/gdb/gdbserver/configure.ac b/gdb/gdbserver/configure.ac index 8476fbd..f15ee1f 100644 --- a/gdb/gdbserver/configure.ac +++ b/gdb/gdbserver/configure.ac @@ -94,6 +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_FUNC_FORK AC_CHECK_FUNCS(getauxval pread pwrite pread64 setns) GDB_AC_COMMON diff --git a/gdb/nat/linux-namespaces.c b/gdb/nat/linux-namespaces.c index fb1467c..e9626ab 100644 --- a/gdb/nat/linux-namespaces.c +++ b/gdb/nat/linux-namespaces.c @@ -32,6 +32,19 @@ /* See nat/linux-namespaces.h. */ int debug_linux_namespaces; +/* Handle systems without fork. */ + +static inline pid_t +do_fork (void) +{ +#ifdef HAVE_FORK + return fork (); +#else + errno = ENOSYS; + return -1; +#endif +} + /* Handle systems without setns. */ static inline int @@ -644,7 +657,7 @@ linux_mntns_get_helper (void) if (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, sv) < 0) return NULL; - h.pid = fork (); + h.pid = do_fork (); if (h.pid < 0) { int saved_errno = errno; -- 2.7.4