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         execlp(pager, pager, NULL);
  11         execl("/bin/sh", "sh", "-c", pager, NULL);
  12 }
  13
  14 void setup_pager(void)
  15 {
  16         pid_t pid;
  17         int fd[2];
  18         const char *pager = getenv("PAGER");
  19
  20         if (!isatty(1))
  21                 return;
  22         if (!pager)
  23                 pager = "less";
  24         else if (!*pager || !strcmp(pager, "cat"))
  25                 return;
  26
  27         pager_in_use = 1; /* means we are emitting to terminal */
  28
  29         if (pipe(fd) < 0)
  30                 return;
  31         pid = fork();
  32         if (pid < 0) {
  33                 close(fd[0]);
  34                 close(fd[1]);
  35                 return;
  36         }
  37
  38         /* return in the child */
  39         if (!pid) {
  40                 dup2(fd[1], 1);
  41                 close(fd[0]);
  42                 close(fd[1]);
  43                 return;
  44         }
  45
  46         /* The original process turns into the PAGER */
  47         dup2(fd[0], 0);
  48         close(fd[0]);
  49         close(fd[1]);
  50
  51         setenv("LESS", "-RS", 0);
  52         run_pager(pager);
  53         die("unable to execute pager '%s'", pager);
  54         exit(255);
  55 }