tools lib subcmd: Support overwriting the pager

Add an interface to the auto pager code that allows callers to overwrite
the pager.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20180918123214.26728-3-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/tools/lib/subcmd/pager.c b/tools/lib/subcmd/pager.c
index 9997a8805a82..e3d47b59b14d 100644
--- a/tools/lib/subcmd/pager.c
+++ b/tools/lib/subcmd/pager.c
@@ -23,6 +23,13 @@ void pager_init(const char *pager_env)
         subcmd_config.pager_env = pager_env;
 }
 
+static const char *forced_pager;
+
+void force_pager(const char *pager)
+{
+        forced_pager = pager;
+}
+
 static void pager_preexec(void)
 {
         /*
@@ -66,7 +73,9 @@ void setup_pager(void)
         const char *pager = getenv(subcmd_config.pager_env);
         struct winsize sz;
 
-        if (!isatty(1))
+        if (forced_pager)
+                pager = forced_pager;
+        if (!isatty(1) && !forced_pager)
                 return;
         if (ioctl(1, TIOCGWINSZ, &sz) == 0)
                 pager_columns = sz.ws_col;