X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fpager.c;h=3fc81820e9b4de7444658197cb98bb7ee3858c9d;hp=6ea25ada65f93f2d6ee2123eedd012edb34dee84;hb=161e54f8719c4a11440d762276cbccbeb1736f8c;hpb=7e2bb92dcae6ee785ff7462aadc8c369fd93715b

diff --git a/src/pager.c b/src/pager.c
index 6ea25ada6..3fc81820e 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -20,6 +20,7 @@
 ***/
 
 #include <sys/types.h>
+#include <fcntl.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
@@ -31,6 +32,18 @@
 
 static pid_t pager_pid = 0;
 
+_noreturn_ static void pager_fallback(void) {
+        ssize_t n;
+        do {
+                n = splice(STDIN_FILENO, NULL, STDOUT_FILENO, NULL, 64*1024, 0);
+        } while (n > 0);
+        if (n < 0) {
+                log_error("Internal pager failed: %m");
+                _exit(EXIT_FAILURE);
+        }
+        _exit(EXIT_SUCCESS);
+}
+
 void pager_open(void) {
         int fd[2];
         const char *pager;
@@ -39,13 +52,13 @@ void pager_open(void) {
         if (pager_pid > 0)
                 return;
 
-        if (isatty(STDOUT_FILENO) <= 0)
-                return;
-
         if ((pager = getenv("SYSTEMD_PAGER")) || (pager = getenv("PAGER")))
                 if (!*pager || streq(pager, "cat"))
                         return;
 
+        if (isatty(STDOUT_FILENO) <= 0)
+                return;
+
         /* Determine and cache number of columns before we spawn the
          * pager so that we get the value from the actual tty */
         columns();
@@ -96,10 +109,9 @@ void pager_open(void) {
 
                 execlp("less", "less", NULL);
                 execlp("more", "more", NULL);
-                execlp("cat", "cat", NULL);
 
-                log_error("Unable to execute pager: %m");
-                _exit(EXIT_FAILURE);
+                pager_fallback();
+                /* not reached */
         }
 
         /* Return in the parent */