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 void run_pager(const char *pager)
   9 {
  10         /*
  11          * Work around bug in "less" by not starting it until we
  12          * have real input
  13          */
  14         fd_set in;
  15
  16         FD_ZERO(&in);
  17         FD_SET(0, &in);
  18         select(1, &in, NULL, &in, NULL);
  19
  20         execlp(pager, pager, NULL);
  21         execl("/bin/sh", "sh", "-c", pager, NULL);
  22 }
  23
  24 void setup_pager(void)
  25 {
  26         pid_t pid;
  27         int fd[2];
  28         const char *pager = getenv("GIT_PAGER");
  29
  30         if (!isatty(1))
  31                 return;
  32         if (!pager) {
  33                 if (!pager_program)
  34                         git_config(git_default_config);
  35                 pager = pager_program;
  36         }
  37         if (!pager)
  38                 pager = getenv("PAGER");
  39         if (!pager)
  40                 pager = "less";
  41         else if (!*pager || !strcmp(pager, "cat"))
  42                 return;
  43
  44         pager_in_use = 1; /* means we are emitting to terminal */
  45
  46         if (pipe(fd) < 0)
  47                 return;
  48         pid = fork();
  49         if (pid < 0) {
  50                 close(fd[0]);
  51                 close(fd[1]);
  52                 return;
  53         }
  54
  55         /* return in the child */
  56         if (!pid) {
  57                 dup2(fd[1], 1);
  58                 close(fd[0]);
  59                 close(fd[1]);
  60                 return;
  61         }
  62
  63         /* The original process turns into the PAGER */
  64         dup2(fd[0], 0);
  65         close(fd[0]);
  66         close(fd[1]);
  67
  68         setenv("LESS", "FRSX", 0);
  69         run_pager(pager);
  70         die("unable to execute pager '%s'", pager);
  71         exit(255);
  72 }