1 // SPDX-License-Identifier: GPL-2.0
2 #include <sys/select.h>
9 #include "run-command.h"
11 #include "subcmd-config.h"
14 * This is split up from the rest of git so that we can do
15 * something different on Windows.
18 static int spawned_pager;
19 static int pager_columns;
21 void pager_init(const char *pager_env)
23 subcmd_config.pager_env = pager_env;
26 static void pager_preexec(void)
29 * Work around bug in "less" by not starting it until we
38 FD_SET(0, &exception);
39 select(1, &in, NULL, &exception, NULL);
41 setenv("LESS", "FRSX", 0);
44 static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
45 static struct child_process pager_process;
47 static void wait_for_pager(void)
51 /* signal EOF to pager */
54 finish_command(&pager_process);
57 static void wait_for_pager_signal(int signo)
64 void setup_pager(void)
66 const char *pager = getenv(subcmd_config.pager_env);
71 if (ioctl(1, TIOCGWINSZ, &sz) == 0)
72 pager_columns = sz.ws_col;
74 pager = getenv("PAGER");
75 if (!(pager || access("/usr/bin/pager", X_OK)))
76 pager = "/usr/bin/pager";
77 if (!(pager || access("/usr/bin/less", X_OK)))
78 pager = "/usr/bin/less";
81 if (!*pager || !strcmp(pager, "cat"))
84 spawned_pager = 1; /* means we are emitting to terminal */
87 pager_argv[2] = pager;
88 pager_process.argv = pager_argv;
89 pager_process.in = -1;
90 pager_process.preexec_cb = pager_preexec;
92 if (start_command(&pager_process))
95 /* original process continues, but writes to the pipe */
96 dup2(pager_process.in, 1);
98 dup2(pager_process.in, 2);
99 close(pager_process.in);
101 /* this makes sure that the parent terminates after the pager */
102 sigchain_push_common(wait_for_pager_signal);
103 atexit(wait_for_pager);
106 int pager_in_use(void)
108 return spawned_pager;
111 int pager_get_columns(void)
115 s = getenv("COLUMNS");
119 return (pager_columns ? pager_columns : 80) - 2;