monitor/display.c

   1 // SPDX-License-Identifier: LGPL-2.1-or-later
   2 /*
   3  *
   4  *  BlueZ - Bluetooth protocol stack for Linux
   5  *
   6  *  Copyright (C) 2011-2014  Intel Corporation
   7  *  Copyright (C) 2002-2010  Marcel Holtmann <marcel@holtmann.org>
   8  *
   9  *
  10  */
  11
  12 #ifdef HAVE_CONFIG_H
  13 #include <config.h>
  14 #endif
  15
  16 #include <stdio.h>
  17 #include <errno.h>
  18 #include <unistd.h>
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <signal.h>
  22 #include <sys/wait.h>
  23 #include <sys/prctl.h>
  24 #include <sys/ioctl.h>
  25 #include <termios.h>
  26
  27 #include "display.h"
  28
  29 static pid_t pager_pid = 0;
  30 #ifndef TIZEN_FEATURE_BLUEZ_MODIFY
  31 int default_pager_num_columns = FALLBACK_TERMINAL_WIDTH;
  32 #endif
  33
  34 enum monitor_color setting_monitor_color = COLOR_AUTO;
  35
  36 void set_monitor_color(enum monitor_color color)
  37 {
  38         setting_monitor_color = color;
  39 }
  40
  41 bool use_color(void)
  42 {
  43         static int cached_use_color = -1;
  44
  45         if (setting_monitor_color == COLOR_ALWAYS)
  46                 cached_use_color = 1;
  47         else if (setting_monitor_color == COLOR_NEVER)
  48                 cached_use_color = 0;
  49         else if (__builtin_expect(!!(cached_use_color < 0), 0))
  50                 cached_use_color = isatty(STDOUT_FILENO) > 0 || pager_pid > 0;
  51
  52         return cached_use_color;
  53 }
  54
  55 #ifndef TIZEN_FEATURE_BLUEZ_MODIFY
  56 void set_default_pager_num_columns(int num_columns)
  57 {
  58         default_pager_num_columns = num_columns;
  59 }
  60 #endif
  61
  62 int num_columns(void)
  63 {
  64         static int cached_num_columns = -1;
  65
  66         if (__builtin_expect(!!(cached_num_columns < 0), 0)) {
  67                 struct winsize ws;
  68
  69                 if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) < 0 ||
  70                                                                 ws.ws_col == 0)
  71 #ifdef TIZEN_FEATURE_BLUEZ_MODIFY
  72                         cached_num_columns = FALLBACK_TERMINAL_WIDTH;
  73 #else
  74                         cached_num_columns = default_pager_num_columns;
  75 #endif
  76                 else
  77                         cached_num_columns = ws.ws_col;
  78         }
  79
  80         return cached_num_columns;
  81 }
  82
  83 static void close_pipe(int p[])
  84 {
  85         if (p[0] >= 0)
  86                 close(p[0]);
  87         if (p[1] >= 0)
  88                 close(p[1]);
  89 }
  90
  91 static void wait_for_terminate(pid_t pid)
  92 {
  93         siginfo_t dummy;
  94
  95         for (;;) {
  96                 memset(&dummy, 0, sizeof(dummy));
  97
  98                 if (waitid(P_PID, pid, &dummy, WEXITED) < 0) {
  99                         if (errno == EINTR)
 100                                 continue;
 101                         return;
 102                 }
 103
 104                 return;
 105         }
 106 }
 107
 108 void open_pager(void)
 109 {
 110         const char *pager;
 111         pid_t parent_pid;
 112         int fd[2];
 113
 114         if (pager_pid > 0)
 115                 return;
 116
 117         pager = getenv("PAGER");
 118         if (pager) {
 119                 if (!*pager || strcmp(pager, "cat") == 0)
 120                         return;
 121         }
 122
 123         if (!(isatty(STDOUT_FILENO) > 0))
 124                 return;
 125
 126         num_columns();
 127
 128         if (pipe(fd) < 0) {
 129                 perror("Failed to create pager pipe");
 130                 return;
 131         }
 132
 133         parent_pid = getpid();
 134
 135         pager_pid = fork();
 136         if (pager_pid < 0) {
 137                 perror("Failed to fork pager");
 138                 close_pipe(fd);
 139                 return;
 140         }
 141
 142         if (pager_pid == 0) {
 143                 dup2(fd[0], STDIN_FILENO);
 144                 close_pipe(fd);
 145
 146                 setenv("LESS", "FRSX", 0);
 147
 148                 if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
 149                         _exit(EXIT_FAILURE);
 150
 151                 if (getppid() != parent_pid)
 152                         _exit(EXIT_SUCCESS);
 153
 154                 if (pager) {
 155                         execlp(pager, pager, NULL);
 156                         execl("/bin/sh", "sh", "-c", pager, NULL);
 157                 }
 158
 159                 execlp("pager", "pager", NULL);
 160                 execlp("less", "less", NULL);
 161                 execlp("more", "more", NULL);
 162
 163                 _exit(EXIT_FAILURE);
 164         }
 165
 166         if (dup2(fd[1], STDOUT_FILENO) < 0) {
 167                 perror("Failed to duplicate pager pipe");
 168                 return;
 169         }
 170
 171         close_pipe(fd);
 172 }
 173
 174 void close_pager(void)
 175 {
 176         if (pager_pid <= 0)
 177                 return;
 178
 179         fclose(stdout);
 180         kill(pager_pid, SIGCONT);
 181         wait_for_terminate(pager_pid);
 182         pager_pid = 0;
 183 }