1#include "cache.h"
2#include "run-command.h"
3#include "sigchain.h"
4
5/*
6 * This is split up from the rest of git so that we can do
7 * something different on Windows.
8 */
9
10static int spawned_pager;
11
12static void pager_preexec(void)
13{
14	/*
15	 * Work around bug in "less" by not starting it until we
16	 * have real input
17	 */
18	fd_set in;
19
20	FD_ZERO(&in);
21	FD_SET(0, &in);
22	select(1, &in, NULL, &in, NULL);
23
24	setenv("LESS", "FRSX", 0);
25}
26
27static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
28static struct child_process pager_process;
29
30static void wait_for_pager(void)
31{
32	fflush(stdout);
33	fflush(stderr);
34	/* signal EOF to pager */
35	close(1);
36	close(2);
37	finish_command(&pager_process);
38}
39
40static void wait_for_pager_signal(int signo)
41{
42	wait_for_pager();
43	sigchain_pop(signo);
44	raise(signo);
45}
46
47void setup_pager(void)
48{
49	const char *pager = getenv("PERF_PAGER");
50
51	if (!isatty(1))
52		return;
53	if (!pager)
54		pager = getenv("PAGER");
55	if (!(pager || access("/usr/bin/pager", X_OK)))
56		pager = "/usr/bin/pager";
57	if (!(pager || access("/usr/bin/less", X_OK)))
58		pager = "/usr/bin/less";
59	if (!pager)
60		pager = "cat";
61	if (!*pager || !strcmp(pager, "cat"))
62		return;
63
64	spawned_pager = 1; /* means we are emitting to terminal */
65
66	/* spawn the pager */
67	pager_argv[2] = pager;
68	pager_process.argv = pager_argv;
69	pager_process.in = -1;
70	pager_process.preexec_cb = pager_preexec;
71
72	if (start_command(&pager_process))
73		return;
74
75	/* original process continues, but writes to the pipe */
76	dup2(pager_process.in, 1);
77	if (isatty(2))
78		dup2(pager_process.in, 2);
79	close(pager_process.in);
80
81	/* this makes sure that the parent terminates after the pager */
82	sigchain_push_common(wait_for_pager_signal);
83	atexit(wait_for_pager);
84}
85
86int pager_in_use(void)
87{
88	const char *env;
89
90	if (spawned_pager)
91		return 1;
92
93	env = getenv("PERF_PAGER_IN_USE");
94	return env ? perf_config_bool("PERF_PAGER_IN_USE", env) : 0;
95}
96