linux_dsm_epyc7002/tools/perf/util/pager.c
Avik Sil ea1b3ebac9 perf tools: Fix pager on minimal-install embedded systems
Some Distributions may lack "less" package being included by default,
e.g., Linaro nano rootfs. In those cases use the portable "pager"
command instead of "less".

Signed-off-by: Avik Sil <avik.sil@linaro.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338287725-26382-1-git-send-email-avik.sil@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-05-30 15:10:39 -03:00

101 lines
1.9 KiB
C

#include "cache.h"
#include "run-command.h"
#include "sigchain.h"
/*
* This is split up from the rest of git so that we can do
* something different on Windows.
*/
static int spawned_pager;
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;
static void wait_for_pager(void)
{
fflush(stdout);
fflush(stderr);
/* signal EOF to pager */
close(1);
close(2);
finish_command(&pager_process);
}
static void wait_for_pager_signal(int signo)
{
wait_for_pager();
sigchain_pop(signo);
raise(signo);
}
void setup_pager(void)
{
const char *pager = getenv("PERF_PAGER");
if (!isatty(1))
return;
if (!pager) {
if (!pager_program)
perf_config(perf_default_config, NULL);
pager = pager_program;
}
if (!pager)
pager = getenv("PAGER");
if (!pager) {
if (!access("/usr/bin/pager", X_OK))
pager = "/usr/bin/pager";
}
if (!pager)
pager = "less";
else if (!*pager || !strcmp(pager, "cat"))
return;
spawned_pager = 1; /* means we are emitting to terminal */
/* spawn the pager */
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;
/* original process continues, but writes to the pipe */
dup2(pager_process.in, 1);
if (isatty(2))
dup2(pager_process.in, 2);
close(pager_process.in);
/* this makes sure that the parent terminates after the pager */
sigchain_push_common(wait_for_pager_signal);
atexit(wait_for_pager);
}
int pager_in_use(void)
{
const char *env;
if (spawned_pager)
return 1;
env = getenv("PERF_PAGER_IN_USE");
return env ? perf_config_bool("PERF_PAGER_IN_USE", env) : 0;
}