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
10 static int spawned_pager;
11
pager_preexec(void)12 static 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
27 static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
28 static struct child_process pager_process;
29
wait_for_pager(void)30 static 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
wait_for_pager_signal(int signo)40 static void wait_for_pager_signal(int signo)
41 {
42 wait_for_pager();
43 sigchain_pop(signo);
44 raise(signo);
45 }
46
setup_pager(void)47 void setup_pager(void)
48 {
49 const char *pager = getenv("PERF_PAGER");
50
51 if (!isatty(1))
52 return;
53 if (!pager) {
54 if (!pager_program)
55 perf_config(perf_default_config, NULL);
56 pager = pager_program;
57 }
58 if (!pager)
59 pager = getenv("PAGER");
60 if (!pager)
61 pager = "less";
62 else if (!*pager || !strcmp(pager, "cat"))
63 return;
64
65 spawned_pager = 1; /* means we are emitting to terminal */
66
67 /* spawn the pager */
68 pager_argv[2] = pager;
69 pager_process.argv = pager_argv;
70 pager_process.in = -1;
71 pager_process.preexec_cb = pager_preexec;
72
73 if (start_command(&pager_process))
74 return;
75
76 /* original process continues, but writes to the pipe */
77 dup2(pager_process.in, 1);
78 if (isatty(2))
79 dup2(pager_process.in, 2);
80 close(pager_process.in);
81
82 /* this makes sure that the parent terminates after the pager */
83 sigchain_push_common(wait_for_pager_signal);
84 atexit(wait_for_pager);
85 }
86
pager_in_use(void)87 int pager_in_use(void)
88 {
89 const char *env;
90
91 if (spawned_pager)
92 return 1;
93
94 env = getenv("PERF_PAGER_IN_USE");
95 return env ? perf_config_bool("PERF_PAGER_IN_USE", env) : 0;
96 }
97