src/freedreno/decode/pager.c

   1 /*
   2  * Copyright (c) 2018 Rob Clark <robdclark@gmail.com>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24 #include <errno.h>
  25 #include <signal.h>
  26 #include <stdbool.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <sys/types.h>
  31 #include <sys/wait.h>
  32 #include <unistd.h>
  33
  34 #include "pager.h"
  35
  36 static pid_t pager_pid;
  37
  38
  39 static void
  40 pager_death(int n)
  41 {
  42         exit(0);
  43 }
  44
  45 void
  46 pager_open(void)
  47 {
  48         int fd[2];
  49
  50         if (pipe(fd) < 0) {
  51                 fprintf(stderr, "Failed to create pager pipe: %m\n");
  52                 exit(-1);
  53         }
  54
  55         pager_pid = fork();
  56         if (pager_pid < 0) {
  57                 fprintf(stderr, "Failed to fork pager: %m\n");
  58                 exit(-1);
  59         }
  60
  61         if (pager_pid == 0) {
  62                 const char* less_opts;
  63
  64                 dup2(fd[0], STDIN_FILENO);
  65                 close(fd[0]);
  66                 close(fd[1]);
  67
  68                 less_opts = "FRSMKX";
  69                 setenv("LESS", less_opts, 1);
  70
  71                 execlp("less", "less", NULL);
  72
  73         } else {
  74                 /* we want to kill the parent process when pager exits: */
  75                 signal(SIGCHLD, pager_death);
  76                 dup2(fd[1], STDOUT_FILENO);
  77                 close(fd[0]);
  78                 close(fd[1]);
  79         }
  80 }
  81
  82 int
  83 pager_close(void)
  84 {
  85         siginfo_t status;
  86
  87         close(STDOUT_FILENO);
  88
  89         while (true) {
  90                 memset(&status, 0, sizeof(status));
  91                 if (waitid(P_PID, pager_pid, &status, WEXITED) < 0) {
  92                         if (errno == EINTR)
  93                                 continue;
  94                         return -errno;
  95                 }
  96
  97                 return 0;
  98         }
  99 }