Messages in this thread | | | Date | Fri, 2 Feb 2018 19:38:51 -0500 | From | Arvind Sankar <> | Subject | Re: [PATCH] tools: libsubcmd: Drop the less hack that was inherited from Git. |
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Hi, it looks like Sergey has put in a patch to fix the aliasing, looking at the linux-next tree.
Are we still looking to remove this hack altogether?
Thanks
On Thu, Jan 25, 2018 at 08:24:26AM -0500, Arvind Sankar wrote: > Thanks. > > This was found because gcc 8 appears to be enabling -Wrestrict in -Wall, > so there is a build failure with mainline gcc. > > On Thu, Jan 25, 2018 at 05:16:52AM -0300, Arnaldo Carvalho de Melo wrote: > > Em Wed, Jan 24, 2018 at 02:54:11PM -0600, Josh Poimboeuf escreveu: > > > On Tue, Jan 23, 2018 at 07:38:37PM -0500, Arvind Sankar wrote: > > > > We inherited this hack with the original code from the Git project. The > > > > select call is invalid as the two fd_set pointers should not be aliased. > > > > > > > > We could fix it, but the Git project removed this hack in 2012 in commit > > > > e8320f3 (pager: drop "wait for output to run less" hack). The bug it > > > > worked around was apparently fixed in less back in June 2007. > > > > > > > > So remove the hack from here as well. > > > > > > > > Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> > > > > > > Looks good to me. > > > > > > Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> > > > > > > Libsubcmd is used by perf and objtool, so adding the perf maintainers to > > > CC. Arnaldo, do you want to pick this one up? > > > > Sure, I'll put it in my perf/core branch. > > > > - Arnaldo > > > > > > --- > > > > tools/lib/subcmd/pager.c | 17 ----------------- > > > > tools/lib/subcmd/run-command.c | 2 -- > > > > tools/lib/subcmd/run-command.h | 1 - > > > > 3 files changed, 20 deletions(-) > > > > > > > > diff --git a/tools/lib/subcmd/pager.c b/tools/lib/subcmd/pager.c > > > > index 5ba754d17952..94d61d9b511f 100644 > > > > --- a/tools/lib/subcmd/pager.c > > > > +++ b/tools/lib/subcmd/pager.c > > > > @@ -1,5 +1,4 @@ > > > > // SPDX-License-Identifier: GPL-2.0 > > > > -#include <sys/select.h> > > > > #include <stdlib.h> > > > > #include <stdio.h> > > > > #include <string.h> > > > > @@ -23,21 +22,6 @@ void pager_init(const char *pager_env) > > > > subcmd_config.pager_env = pager_env; > > > > } > > > > > > > > -static void pager_preexec(void) > > > > -{ > > > > - /* > > > > - * Work around bug in "less" by not starting it until we > > > > - * have real input > > > > - */ > > > > - fd_set in; > > > > - > > > > - FD_ZERO(&in); > > > > - FD_SET(0, &in); > > > > - select(1, &in, NULL, &in, NULL); > > > > - > > > > - setenv("LESS", "FRSX", 0); > > > > -} > > > > - > > > > static const char *pager_argv[] = { "sh", "-c", NULL, NULL }; > > > > static struct child_process pager_process; > > > > > > > > @@ -84,7 +68,6 @@ void setup_pager(void) > > > > pager_argv[2] = pager; > > > > pager_process.argv = pager_argv; > > > > pager_process.in = -1; > > > > - pager_process.preexec_cb = pager_preexec; > > > > > > > > if (start_command(&pager_process)) > > > > return; > > > > diff --git a/tools/lib/subcmd/run-command.c b/tools/lib/subcmd/run-command.c > > > > index 5cdac2162532..9e9dca717ed7 100644 > > > > --- a/tools/lib/subcmd/run-command.c > > > > +++ b/tools/lib/subcmd/run-command.c > > > > @@ -120,8 +120,6 @@ int start_command(struct child_process *cmd) > > > > unsetenv(*cmd->env); > > > > } > > > > } > > > > - if (cmd->preexec_cb) > > > > - cmd->preexec_cb(); > > > > if (cmd->exec_cmd) { > > > > execv_cmd(cmd->argv); > > > > } else { > > > > diff --git a/tools/lib/subcmd/run-command.h b/tools/lib/subcmd/run-command.h > > > > index 17d969c6add3..6256268802b5 100644 > > > > --- a/tools/lib/subcmd/run-command.h > > > > +++ b/tools/lib/subcmd/run-command.h > > > > @@ -46,7 +46,6 @@ struct child_process { > > > > unsigned no_stderr:1; > > > > unsigned exec_cmd:1; /* if this is to be external sub-command */ > > > > unsigned stdout_to_stderr:1; > > > > - void (*preexec_cb)(void); > > > > }; > > > > > > > > int start_command(struct child_process *); > > > > -- > > > > 2.13.6 > > > > > > > > > > -- > > > Josh
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