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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
2f4ce5ec JP |
2 | #include <sys/select.h> |
3 | #include <stdlib.h> | |
4 | #include <stdio.h> | |
5 | #include <string.h> | |
6 | #include <signal.h> | |
61eb2eb4 | 7 | #include <sys/ioctl.h> |
2f4ce5ec | 8 | #include "pager.h" |
a930d2c0 IM |
9 | #include "run-command.h" |
10 | #include "sigchain.h" | |
096d3558 | 11 | #include "subcmd-config.h" |
a930d2c0 IM |
12 | |
13 | /* | |
14 | * This is split up from the rest of git so that we can do | |
15 | * something different on Windows. | |
16 | */ | |
17 | ||
18 | static int spawned_pager; | |
61eb2eb4 | 19 | static int pager_columns; |
a930d2c0 | 20 | |
096d3558 JP |
21 | void pager_init(const char *pager_env) |
22 | { | |
23 | subcmd_config.pager_env = pager_env; | |
24 | } | |
25 | ||
a930d2c0 IM |
26 | static void pager_preexec(void) |
27 | { | |
28 | /* | |
29 | * Work around bug in "less" by not starting it until we | |
30 | * have real input | |
31 | */ | |
32 | fd_set in; | |
33 | ||
34 | FD_ZERO(&in); | |
35 | FD_SET(0, &in); | |
36 | select(1, &in, NULL, &in, NULL); | |
37 | ||
38 | setenv("LESS", "FRSX", 0); | |
39 | } | |
a930d2c0 IM |
40 | |
41 | static const char *pager_argv[] = { "sh", "-c", NULL, NULL }; | |
42 | static struct child_process pager_process; | |
43 | ||
44 | static void wait_for_pager(void) | |
45 | { | |
46 | fflush(stdout); | |
47 | fflush(stderr); | |
48 | /* signal EOF to pager */ | |
49 | close(1); | |
50 | close(2); | |
51 | finish_command(&pager_process); | |
52 | } | |
53 | ||
54 | static void wait_for_pager_signal(int signo) | |
55 | { | |
56 | wait_for_pager(); | |
57 | sigchain_pop(signo); | |
58 | raise(signo); | |
59 | } | |
60 | ||
61 | void setup_pager(void) | |
62 | { | |
096d3558 | 63 | const char *pager = getenv(subcmd_config.pager_env); |
61eb2eb4 | 64 | struct winsize sz; |
a930d2c0 IM |
65 | |
66 | if (!isatty(1)) | |
67 | return; | |
61eb2eb4 AK |
68 | if (ioctl(1, TIOCGWINSZ, &sz) == 0) |
69 | pager_columns = sz.ws_col; | |
a930d2c0 IM |
70 | if (!pager) |
71 | pager = getenv("PAGER"); | |
21cfc5e1 ML |
72 | if (!(pager || access("/usr/bin/pager", X_OK))) |
73 | pager = "/usr/bin/pager"; | |
74 | if (!(pager || access("/usr/bin/less", X_OK))) | |
75 | pager = "/usr/bin/less"; | |
a930d2c0 | 76 | if (!pager) |
21cfc5e1 ML |
77 | pager = "cat"; |
78 | if (!*pager || !strcmp(pager, "cat")) | |
a930d2c0 IM |
79 | return; |
80 | ||
81 | spawned_pager = 1; /* means we are emitting to terminal */ | |
82 | ||
83 | /* spawn the pager */ | |
84 | pager_argv[2] = pager; | |
85 | pager_process.argv = pager_argv; | |
86 | pager_process.in = -1; | |
a930d2c0 | 87 | pager_process.preexec_cb = pager_preexec; |
fde953c1 | 88 | |
a930d2c0 IM |
89 | if (start_command(&pager_process)) |
90 | return; | |
91 | ||
92 | /* original process continues, but writes to the pipe */ | |
93 | dup2(pager_process.in, 1); | |
94 | if (isatty(2)) | |
95 | dup2(pager_process.in, 2); | |
96 | close(pager_process.in); | |
97 | ||
98 | /* this makes sure that the parent terminates after the pager */ | |
99 | sigchain_push_common(wait_for_pager_signal); | |
100 | atexit(wait_for_pager); | |
101 | } | |
102 | ||
103 | int pager_in_use(void) | |
104 | { | |
a871a775 | 105 | return spawned_pager; |
a930d2c0 | 106 | } |
61eb2eb4 AK |
107 | |
108 | int pager_get_columns(void) | |
109 | { | |
110 | char *s; | |
111 | ||
112 | s = getenv("COLUMNS"); | |
113 | if (s) | |
114 | return atoi(s); | |
115 | ||
116 | return (pager_columns ? pager_columns : 80) - 2; | |
117 | } |