mirror of https://gitee.com/openkylin/linux.git
130 lines
2.5 KiB
C
130 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <sys/select.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <signal.h>
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#include <sys/ioctl.h>
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#include "pager.h"
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#include "run-command.h"
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#include "sigchain.h"
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#include "subcmd-config.h"
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/*
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* This is split up from the rest of git so that we can do
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* something different on Windows.
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*/
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static int spawned_pager;
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static int pager_columns;
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void pager_init(const char *pager_env)
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{
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subcmd_config.pager_env = pager_env;
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}
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static const char *forced_pager;
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void force_pager(const char *pager)
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{
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forced_pager = pager;
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}
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static void pager_preexec(void)
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{
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/*
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* Work around bug in "less" by not starting it until we
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* have real input
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*/
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fd_set in;
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fd_set exception;
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FD_ZERO(&in);
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FD_ZERO(&exception);
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FD_SET(0, &in);
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FD_SET(0, &exception);
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select(1, &in, NULL, &exception, NULL);
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setenv("LESS", "FRSX", 0);
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}
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static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
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static struct child_process pager_process;
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static void wait_for_pager(void)
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{
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fflush(stdout);
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fflush(stderr);
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/* signal EOF to pager */
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close(1);
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close(2);
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finish_command(&pager_process);
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}
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static void wait_for_pager_signal(int signo)
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{
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wait_for_pager();
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sigchain_pop(signo);
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raise(signo);
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}
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void setup_pager(void)
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{
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const char *pager = getenv(subcmd_config.pager_env);
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struct winsize sz;
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if (forced_pager)
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pager = forced_pager;
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if (!isatty(1) && !forced_pager)
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return;
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if (ioctl(1, TIOCGWINSZ, &sz) == 0)
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pager_columns = sz.ws_col;
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if (!pager)
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pager = getenv("PAGER");
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if (!(pager || access("/usr/bin/pager", X_OK)))
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pager = "/usr/bin/pager";
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if (!(pager || access("/usr/bin/less", X_OK)))
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pager = "/usr/bin/less";
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if (!pager)
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pager = "cat";
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if (!*pager || !strcmp(pager, "cat"))
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return;
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spawned_pager = 1; /* means we are emitting to terminal */
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/* spawn the pager */
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pager_argv[2] = pager;
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pager_process.argv = pager_argv;
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pager_process.in = -1;
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pager_process.preexec_cb = pager_preexec;
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if (start_command(&pager_process))
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return;
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/* original process continues, but writes to the pipe */
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dup2(pager_process.in, 1);
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if (isatty(2))
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dup2(pager_process.in, 2);
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close(pager_process.in);
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/* this makes sure that the parent terminates after the pager */
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sigchain_push_common(wait_for_pager_signal);
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atexit(wait_for_pager);
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}
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int pager_in_use(void)
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{
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return spawned_pager;
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}
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int pager_get_columns(void)
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{
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char *s;
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s = getenv("COLUMNS");
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if (s)
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return atoi(s);
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return (pager_columns ? pager_columns : 80) - 2;
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}
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