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[paraslash.git] / stdin.c

diff --git a/stdin.c b/stdin.c
index 4b77a3d8e739a49793b06773993ba4396b05bb27..20b9250e9b7fbf3c252e20dff8891bfeeb5112dd 100644 (file)
--- a/stdin.c
+++ b/stdin.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2013 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -33,7 +33,6 @@ static void stdin_pre_select(struct sched *s, struct task *t)
        struct stdin_task *sit = container_of(t, struct stdin_task, task);
        int ret;
 
-       t->error = 0;
        ret = btr_node_status(sit->btrn, 0, BTR_NT_ROOT);
        if (ret < 0)
                sched_min_delay(s);
@@ -55,22 +54,27 @@ static void stdin_pre_select(struct sched *s, struct task *t)
  * appears to be readable, data is read from stdin and fed into the buffer
  * tree.
  */
-static void stdin_post_select(struct sched *s, struct task *t)
+static int stdin_post_select(struct sched *s, struct task *t)
 {
        struct stdin_task *sit = container_of(t, struct stdin_task, task);
        ssize_t ret;
        size_t sz, n;
        char *buf = NULL;
 
-       t->error = 0;
        ret = btr_node_status(sit->btrn, 0, BTR_NT_ROOT);
        if (ret < 0)
                goto err;
        if (ret == 0)
-               return;
+               return 0;
        sz = btr_pool_get_buffer(sit->btrp, &buf);
        if (sz == 0)
-               return;
+               return 0;
+       if (sit->must_set_nonblock_flag) {
+               ret = mark_fd_nonblocking(STDIN_FILENO);
+               if (ret < 0)
+                       goto err;
+               sit->must_set_nonblock_flag = false;
+       }
        /*
         * Do not use the maximal size to avoid having only a single buffer
         * reference for the whole pool. This is bad because if that single
@@ -81,11 +85,13 @@ static void stdin_post_select(struct sched *s, struct task *t)
        if (n > 0)
                btr_add_output_pool(sit->btrp, n, sit->btrn);
        if (ret >= 0)
-               return;
+               return 0;
 err:
-       btr_remove_node(sit->btrn);
+       btr_remove_node(&sit->btrn);
+       /* Revert to blocking mode if necessary. */
+       fcntl(STDIN_FILENO, F_SETFL, sit->fd_flags);
        //btr_pool_free(sit->btrp);
-       t->error = ret;
+       return ret;
 }
 
 /**
@@ -94,8 +100,7 @@ err:
  * \param sit The stdin task structure.
  *
  * This fills in the pre/post select function pointers of the task structure
- * given by \a sit. Moreover, the stdin file desctiptor is set to nonblocking
- * mode, and a buffer tree is created.
+ * given by \a sit and creates a buffer tree for I/O.
  */
 void stdin_set_defaults(struct stdin_task *sit)
 {
@@ -105,9 +110,18 @@ void stdin_set_defaults(struct stdin_task *sit)
        sit->task.post_select = stdin_post_select;
        sit->btrp = btr_pool_new("stdin", 128 * 1024);
        sprintf(sit->task.status, "stdin reader");
-       ret = mark_fd_nonblocking(STDIN_FILENO);
-       if (ret >= 0)
-               return;
-       PARA_EMERG_LOG("%s\n", para_strerror(-ret));
-       exit(EXIT_FAILURE);
+       /*
+        * Both STDIN_FILENO and STDOUT_FILENO may refer to the same open file
+        * description (the terminal), and thus share the same file status
+        * flags. In order to not interfere with the stdout task, we only get
+        * the file status flags for STDIN here and save a copy. The nonblock
+        * flag is set later on the first read.
+        */
+       ret = fcntl(STDIN_FILENO, F_GETFL);
+       if (ret < 0) {
+               PARA_EMERG_LOG("F_GETFL: %s\n", strerror(errno));
+               exit(EXIT_FAILURE);
+       }
+       sit->fd_flags = ret;
+       sit->must_set_nonblock_flag = (sit->fd_flags & O_NONBLOCK) == 0;
 }