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 int pager_in_use;
   9
  10 static void run_pager(const char *pager)
  11 {
  12         execlp(pager, pager, NULL);
  13         execl("/bin/sh", "sh", "-c", pager, NULL);
  14 }
  15
  16 void setup_pager(void)
  17 {
  18         pid_t pid;
  19         int fd[2];
  20         const char *pager = getenv("PAGER");
  21
  22         if (!isatty(1))
  23                 return;
  24         if (!pager)
  25                 pager = "less";
  26         else if (!*pager || !strcmp(pager, "cat"))
  27                 return;
  28
  29         pager_in_use = 1; /* means we are emitting to terminal */
  30
  31         if (pipe(fd) < 0)
  32                 return;
  33         pid = fork();
  34         if (pid < 0) {
  35                 close(fd[0]);
  36                 close(fd[1]);
  37                 return;
  38         }
  39
  40         /* return in the child */
  41         if (!pid) {
  42                 dup2(fd[1], 1);
  43                 close(fd[0]);
  44                 close(fd[1]);
  45                 return;
  46         }
  47
  48         /* The original process turns into the PAGER */
  49         dup2(fd[0], 0);
  50         close(fd[0]);
  51         close(fd[1]);
  52
  53         setenv("LESS", "-RS", 0);
  54         run_pager(pager);
  55         die("unable to execute pager '%s'", pager);
  56         exit(255);
  57 }