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
25 static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
26 static struct child_process pager_process;
27
wait_for_pager(void)28 static void wait_for_pager(void)
29 {
30 fflush(stdout);
31 fflush(stderr);
32 /* signal EOF to pager */
33 close(1);
34 close(2);
35 finish_command(&pager_process);
36 }
37
wait_for_pager_signal(int signo)38 static void wait_for_pager_signal(int signo)
39 {
40 wait_for_pager();
41 sigchain_pop(signo);
42 raise(signo);
43 }
44
setup_pager(void)45 void setup_pager(void)
46 {
47 const char *pager = getenv("PERF_PAGER");
48
49 if (!isatty(1))
50 return;
51 if (!pager) {
52 if (!pager_program)
53 perf_config(perf_default_config, NULL);
54 pager = pager_program;
55 }
56 if (!pager)
57 pager = getenv("PAGER");
58 if (!pager) {
59 if (!access("/usr/bin/pager", X_OK))
60 pager = "/usr/bin/pager";
61 }
62 if (!pager)
63 pager = "cat";
64 else if (!*pager || !strcmp(pager, "cat"))
65 return;
66
67 spawned_pager = 1; /* means we are emitting to terminal */
68
69 /* spawn the pager */
70 pager_argv[2] = pager;
71 pager_process.argv = pager_argv;
72 pager_process.in = -1;
73 pager_process.preexec_cb = pager_preexec;
74
75 if (start_command(&pager_process))
76 return;
77
78 /* original process continues, but writes to the pipe */
79 dup2(pager_process.in, 1);
80 if (isatty(2))
81 dup2(pager_process.in, 2);
82 close(pager_process.in);
83
84 /* this makes sure that the parent terminates after the pager */
85 sigchain_push_common(wait_for_pager_signal);
86 atexit(wait_for_pager);
87 }
88
pager_in_use(void)89 int pager_in_use(void)
90 {
91 const char *env;
92
93 if (spawned_pager)
94 return 1;
95
96 env = getenv("PERF_PAGER_IN_USE");
97 return env ? perf_config_bool("PERF_PAGER_IN_USE", env) : 0;
98 }
99