[Qemu-devel] [PATCH 08/18] qemu-char: Close fd at end of file

[minyard@acm.org]

From: Corey Minyard <cminyard@mvista.com>

The chardev backends that used qemu_chr_open_fd did not get their
file descriptors closed at end of file or when the chardev was closed.
This could result in a file descriptor leak.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
 qemu-char.c |   31 +++++++++++++++++++++++++------
 1 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 6c3e61e..dac319c 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -566,6 +566,7 @@ static int stdio_nb_clients;
 typedef struct {
     int fd_in, fd_out;
     int max_size;
+    int close_fds_on_close;
 } FDCharDriver;
 
 
@@ -584,6 +585,20 @@ static int fd_chr_read_poll(void *opaque)
     return s->max_size;
 }
 
+static void fd_close_fds(FDCharDriver *s)
+{
+    if (!s->close_fds_on_close) {
+        return;
+    }
+
+    if ((s->fd_out != s->fd_in) && (s->fd_out != -1)) {
+        close(s->fd_out);
+    }
+    s->fd_out = -1;
+    close(s->fd_in);
+    s->fd_in = -1;
+}
+
 static void fd_chr_read(void *opaque)
 {
     CharDriverState *chr = opaque;
@@ -600,6 +615,7 @@ static void fd_chr_read(void *opaque)
     if (size == 0) {
         /* FD has been closed. Remove it from the active list.  */
         qemu_set_fd_handler2(s->fd_in, NULL, NULL, NULL, NULL);
+        fd_close_fds(s);
         qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
         return;
     }
@@ -629,6 +645,7 @@ static void fd_chr_close(struct CharDriverState *chr)
         if (display_type == DT_NOGRAPHIC && s->fd_in == 0) {
         } else {
             qemu_set_fd_handler2(s->fd_in, NULL, NULL, NULL, NULL);
+            fd_close_fds(s);
         }
     }
 
@@ -638,13 +655,15 @@ static void fd_chr_close(struct CharDriverState *chr)
 
 /* open a character device to a unix fd */
 static CharDriverState *qemu_chr_open_fd(CharDriverState *chr,
-                                         int fd_in, int fd_out)
+                                         int fd_in, int fd_out,
+                                         int close_fds_on_close)
 {
     FDCharDriver *s;
 
     s = g_malloc0(sizeof(FDCharDriver));
     s->fd_in = fd_in;
     s->fd_out = fd_out;
+    s->close_fds_on_close = close_fds_on_close;
     chr->opaque = s;
     chr->chr_write = fd_chr_write;
     chr->chr_update_read_handler = fd_chr_update_read_handler;
@@ -665,7 +684,7 @@ static CharDriverState *qemu_chr_open_file_out(CharDriverState *chr,
     if (fd_out < 0) {
         return NULL;
     }
-    return qemu_chr_open_fd(chr, -1, fd_out);
+    return qemu_chr_open_fd(chr, -1, fd_out, 1);
 }
 
 static CharDriverState *qemu_chr_open_pipe(CharDriverState *chr, QemuOpts *opts)
@@ -693,7 +712,7 @@ static CharDriverState *qemu_chr_open_pipe(CharDriverState *chr, QemuOpts *opts)
             return NULL;
         }
     }
-    return qemu_chr_open_fd(chr, fd_in, fd_out);
+    return qemu_chr_open_fd(chr, fd_in, fd_out, 1);
 }
 
 
@@ -797,7 +816,7 @@ static CharDriverState *qemu_chr_open_stdio(CharDriverState *chr,
         atexit(term_exit);
     }
 
-    qemu_chr_open_fd(chr, 0, 1);
+    qemu_chr_open_fd(chr, 0, 1, 0);
     chr->chr_close = qemu_chr_close_stdio;
     chr->chr_set_echo = qemu_chr_set_echo_stdio;
     qemu_set_fd_handler2(0, stdio_read_poll, stdio_read, NULL, chr);
@@ -1242,7 +1261,7 @@ static CharDriverState *qemu_chr_open_tty(CharDriverState *chr, QemuOpts *opts)
         return NULL;
     }
     tty_serial_init(fd, 115200, 'N', 8, 1);
-    qemu_chr_open_fd(chr, fd, fd);
+    qemu_chr_open_fd(chr, fd, fd, 1);
     chr->chr_ioctl = tty_serial_ioctl;
     chr->chr_close = qemu_chr_close_tty;
     return chr;
@@ -2316,7 +2335,7 @@ static void tcp_chr_read(void *opaque)
 CharDriverState *qemu_chr_open_eventfd(int eventfd)
 {
     CharDriverState *chr = g_malloc0(sizeof(CharDriverState));
-    return qemu_chr_open_fd(chr, eventfd, eventfd);
+    return qemu_chr_open_fd(chr, eventfd, eventfd, 0);
 }
 #endif
 
-- 
1.7.4.1