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 }
  12
  13 void setup_pager(void)
  14 {
  15         pid_t pid;
  16         int fd[2];
  17         const char *pager = getenv("PAGER");
  18
  19         if (!isatty(1))
  20                 return;
  21         if (!pager)
  22                 pager = "less";
  23         else if (!*pager)
  24                 return;
  25
  26         if (pipe(fd) < 0)
  27                 return;
  28         pid = fork();
  29         if (pid < 0) {
  30                 close(fd[0]);
  31                 close(fd[1]);
  32                 return;
  33         }
  34
  35         /* return in the child */
  36         if (!pid) {
  37                 dup2(fd[1], 1);
  38                 close(fd[0]);
  39                 close(fd[1]);
  40                 return;
  41         }
  42
  43         /* The original process turns into the PAGER */
  44         dup2(fd[0], 0);
  45         close(fd[0]);
  46         close(fd[1]);
  47
  48         setenv("LESS", "-S", 0);
  49         run_pager(pager);
  50         exit(255);
  51 }