vss: Avoid use after free in vss_send().

[paraslash.git] / stdout.c

diff --git a/stdout.c b/stdout.c
index 33770c46d36e0ea772a84abbdda9babb9f271fc3..29db2b7e3e28f050d72577a6d8b533c18ed54be8 100644 (file)
--- a/stdout.c
+++ b/stdout.c
@@ -1,13 +1,11 @@
 /*
- * Copyright (C) 2006-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
 /** \file stdout.c Functions that deal with writing to stdout. */
 
-#include <assert.h>
-
 #include "para.h"
 #include "list.h"
 #include "sched.h"
@@ -16,21 +14,12 @@
 #include "stdout.h"
 #include "buffer_tree.h"
 
-/**
- * The pre_select function of the stdout task.
- *
- * \param s The scheduler this task was registered to.
- * \param t The task structure of the stdout task.
- *
- * This function is always successful. If there is input data available, it
- * adds \p STDOUT_FILENO to the write fd set of \a s.
- */
-static void stdout_pre_select(struct sched *s, struct task *t)
+/* Add STDOUT_FILENO to the write fd set if there is input data available. */
+static void stdout_pre_select(struct sched *s, void *context)
 {
-       struct stdout_task *sot = container_of(t, struct stdout_task, task);
+       struct stdout_task *sot = context;
        int ret;
 
-       t->error = 0;
        ret = btr_node_status(sot->btrn, 0, BTR_NT_LEAF);
        if (ret > 0)
                para_fd_set(STDOUT_FILENO, &s->wfds, &s->max_fileno);
@@ -38,64 +27,75 @@ static void stdout_pre_select(struct sched *s, struct task *t)
                sched_min_delay(s);
 }
 
-/**
- * The post select function of the stdout task.
- *
- * \param s The scheduler this task was registered to.
- * \param t The task structure of the stdout task.
- *
- * This function writes input data from the buffer tree to stdout if \p
+/*
+ * This function writes input data from the buffer tree to stdout if
  * STDOUT_FILENO is writable.
  */
-static void stdout_post_select(struct sched *s, struct task *t)
+static int stdout_post_select(struct sched *s, void *context)
 {
-       struct stdout_task *sot = container_of(t, struct stdout_task, task);
+       struct stdout_task *sot = context;
        struct btr_node *btrn = sot->btrn;
        int ret;
        char *buf;
        size_t sz;
 
-       t->error = 0;
        ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
        if (ret < 0)
                goto out;
        if (ret == 0)
-               return;
+               return 0;
        if (!FD_ISSET(STDOUT_FILENO, &s->wfds))
-               return;
+               return 0;
 
+       if (sot->must_set_nonblock_flag) {
+               ret = mark_fd_nonblocking(STDOUT_FILENO);
+               if (ret < 0)
+                       goto out;
+               sot->must_set_nonblock_flag = false;
+       }
        for (;;) {
                sz = btr_next_buffer(btrn, &buf);
                if (sz == 0)
                        break;
-               ret = write_nonblock(STDOUT_FILENO, buf, sz);
+               ret = xwrite(STDOUT_FILENO, buf, sz);
                if (ret <= 0)
                        break;
                btr_consume(btrn, ret);
        }
 out:
-       if (ret < 0)
-               btr_remove_node(btrn);
-       t->error = ret;
+       if (ret < 0) {
+               btr_remove_node(&sot->btrn);
+               /* Revert to blocking mode if necessary. */
+               fcntl(STDOUT_FILENO, F_SETFL, sot->fd_flags);
+       }
+       return ret;
 }
+
 /**
- * Initialize a stdout task structure with default values.
+ * Register a stdout task structure.
  *
- * \param sot The stdout task structure.
+ * \param sot The stdout task structure to register.
+ * \param s The task will be added to this scheduler's task list.
  *
- * This fills in the pre/post select function pointers of the task structure
- * given by \a sot and sets the stdout file descriptor to nonblocking mode.
+ * This sets up \a sot and registers a task with \a sot as context pointer.
  */
-void stdout_set_defaults(struct stdout_task *sot)
+void stdout_task_register(struct stdout_task *sot, struct sched *s)
 {
        int ret;
+       struct task_info ti = {
+               .pre_select = stdout_pre_select,
+               .post_select = stdout_post_select,
+               .context = sot,
+               .name = "stdout",
+       };
 
-       sot->task.pre_select = stdout_pre_select;
-       sot->task.post_select = stdout_post_select;
-       sprintf(sot->task.status, "stdout");
-       ret = mark_fd_nonblocking(STDOUT_FILENO);
-       if (ret >= 0)
-               return;
-       PARA_EMERG_LOG("%s\n", para_strerror(-ret));
-       exit(EXIT_FAILURE);
+       /* See stdin.c for details. */
+       ret = fcntl(STDOUT_FILENO, F_GETFL);
+       if (ret < 0) {
+               PARA_EMERG_LOG("F_GETFL: %s\n", strerror(errno));
+               exit(EXIT_FAILURE);
+       }
+       sot->fd_flags = ret;
+       sot->must_set_nonblock_flag = (sot->fd_flags & O_NONBLOCK) == 0;
+       sot->task = task_register(&ti, s);
 }