pager.c

   1 #include "cache.h"
   2
   3 /*
   4  * This is split up from the rest of git so that we might do
   5  * something different on Windows, for example.
   6  */
   7
   8 static int spawned_pager;
   9
  10 static void run_pager(const char *pager)
  11 {
  12         /*
  13          * Work around bug in "less" by not starting it until we
  14          * have real input
  15          */
  16         fd_set in;
  17
  18         FD_ZERO(&in);
  19         FD_SET(0, &in);
  20         select(1, &in, NULL, &in, NULL);
  21
  22         execlp(pager, pager, NULL);
  23         execl("/bin/sh", "sh", "-c", pager, NULL);
  24 }
  25
  26 void setup_pager(void)
  27 {
  28         pid_t pid;
  29         int fd[2];
  30         const char *pager = getenv("GIT_PAGER");
  31
  32         if (!isatty(1))
  33                 return;
  34         if (!pager) {
  35                 if (!pager_program)
  36                         git_config(git_default_config, NULL);
  37                 pager = pager_program;
  38         }
  39         if (!pager)
  40                 pager = getenv("PAGER");
  41         if (!pager)
  42                 pager = "less";
  43         else if (!*pager || !strcmp(pager, "cat"))
  44                 return;
  45
  46         spawned_pager = 1; /* means we are emitting to terminal */
  47
  48         if (pipe(fd) < 0)
  49                 return;
  50         pid = fork();
  51         if (pid < 0) {
  52                 close(fd[0]);
  53                 close(fd[1]);
  54                 return;
  55         }
  56
  57         /* return in the child */
  58         if (!pid) {
  59                 dup2(fd[1], 1);
  60                 dup2(fd[1], 2);
  61                 close(fd[0]);
  62                 close(fd[1]);
  63                 return;
  64         }
  65
  66         /* The original process turns into the PAGER */
  67         dup2(fd[0], 0);
  68         close(fd[0]);
  69         close(fd[1]);
  70
  71         setenv("LESS", "FRSX", 0);
  72         run_pager(pager);
  73         die("unable to execute pager '%s'", pager);
  74         exit(255);
  75 }
  76
  77 int pager_in_use(void)
  78 {
  79         const char *env;
  80
  81         if (spawned_pager)
  82                 return 1;
  83
  84         env = getenv("GIT_PAGER_IN_USE");
  85         return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
  86 }