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 fd_set exception;
20
21 FD_ZERO(&in);
22 FD_ZERO(&exception);
23 FD_SET(0, &in);
24 FD_SET(0, &exception);
25 select(1, &in, NULL, &exception, NULL);
26
27 setenv("LESS", "FRSX", 0);
28 }
29
30 static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
31 static struct child_process pager_process;
32
wait_for_pager(void)33 static void wait_for_pager(void)
34 {
35 fflush(stdout);
36 fflush(stderr);
37 /* signal EOF to pager */
38 close(1);
39 close(2);
40 finish_command(&pager_process);
41 }
42
wait_for_pager_signal(int signo)43 static void wait_for_pager_signal(int signo)
44 {
45 wait_for_pager();
46 sigchain_pop(signo);
47 raise(signo);
48 }
49
setup_pager(void)50 void setup_pager(void)
51 {
52 const char *pager = getenv("PERF_PAGER");
53
54 if (!isatty(1))
55 return;
56 if (!pager)
57 pager = getenv("PAGER");
58 if (!(pager || access("/usr/bin/pager", X_OK)))
59 pager = "/usr/bin/pager";
60 if (!(pager || access("/usr/bin/less", X_OK)))
61 pager = "/usr/bin/less";
62 if (!pager)
63 pager = "cat";
64 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