Patchwork [14/18] vl.c: fix warning with _FORTIFY_SOURCE

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Submitter Kirill A. Shutemov
Date Dec. 20, 2009, 1:39 a.m.
Message ID <1261273167-3240-14-git-send-email-kirill@shutemov.name>
Download mbox | patch
Permalink /patch/41500/
State New
Headers show

Comments

Kirill A. Shutemov - Dec. 20, 2009, 1:39 a.m.
CC    i386-softmmu/vl.o
cc1: warnings being treated as errors
/usr/src/RPM/BUILD/qemu-0.11.92/vl.c: In function 'qemu_event_increment':
/usr/src/RPM/BUILD/qemu-0.11.92/vl.c:3404: error: ignoring return value of 'write', declared with attribute warn_unused_result
/usr/src/RPM/BUILD/qemu-0.11.92/vl.c: In function 'main':
/usr/src/RPM/BUILD/qemu-0.11.92/vl.c:5774: error: ignoring return value of 'write', declared with attribute warn_unused_result
/usr/src/RPM/BUILD/qemu-0.11.92/vl.c:6064: error: ignoring return value of 'chdir', declared with attribute warn_unused_result
/usr/src/RPM/BUILD/qemu-0.11.92/vl.c:6083: error: ignoring return value of 'chdir', declared with attribute warn_unused_result
make[1]: *** [vl.o] Error 1

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
---
 vl.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)
Blue Swirl - Dec. 22, 2009, 9:12 p.m.
On Sun, Dec 20, 2009 at 1:39 AM, Kirill A. Shutemov
<kirill@shutemov.name> wrote:
>  CC    i386-softmmu/vl.o
> cc1: warnings being treated as errors
> /usr/src/RPM/BUILD/qemu-0.11.92/vl.c: In function 'qemu_event_increment':
> /usr/src/RPM/BUILD/qemu-0.11.92/vl.c:3404: error: ignoring return value of 'write', declared with attribute warn_unused_result
> /usr/src/RPM/BUILD/qemu-0.11.92/vl.c: In function 'main':
> /usr/src/RPM/BUILD/qemu-0.11.92/vl.c:5774: error: ignoring return value of 'write', declared with attribute warn_unused_result
> /usr/src/RPM/BUILD/qemu-0.11.92/vl.c:6064: error: ignoring return value of 'chdir', declared with attribute warn_unused_result
> /usr/src/RPM/BUILD/qemu-0.11.92/vl.c:6083: error: ignoring return value of 'chdir', declared with attribute warn_unused_result
> make[1]: *** [vl.o] Error 1
>
> Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
> ---
>  vl.c |   15 +++++++++++----
>  1 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/vl.c b/vl.c
> index e606903..60a2c5e 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3383,7 +3383,11 @@ static void qemu_event_increment(void)
>     if (io_thread_fd == -1)
>         return;
>
> -    write(io_thread_fd, &byte, sizeof(byte));
> +    if (write(io_thread_fd, &byte, sizeof(byte)) != sizeof(byte)){
> +        fprintf(stderr, "qemu_event_increment: write() filed: %s\n",
> +                strerror(errno));
> +        exit (1);
> +    }
>  }
>
>  static void qemu_event_read(void *opaque)
> @@ -5767,7 +5771,8 @@ int main(int argc, char **argv, char **envp)
>  #ifndef _WIN32
>         if (daemonize) {
>             uint8_t status = 1;
> -            write(fds[1], &status, 1);
> +            if (write(fds[1], &status, 1) != 1)
> +                perror("write()");
>         } else
>  #endif
>             fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno));
> @@ -6064,7 +6069,8 @@ int main(int argc, char **argv, char **envp)
>        if (len != 1)
>            exit(1);
>
> -       chdir("/");
> +       if (chdir("/"))
> +        exit(1);
>        TFR(fd = qemu_open("/dev/null", O_RDWR));
>        if (fd == -1)
>            exit(1);
> @@ -6083,7 +6089,8 @@ int main(int argc, char **argv, char **envp)
>             fprintf(stderr, "chroot failed\n");
>             exit(1);
>         }
> -        chdir("/");
> +        if (chdir("/"))
> +            exit(1);

Can't comment much on write() parts. chdir() checks are OK, except an
error message would be in order.

Patch

diff --git a/vl.c b/vl.c
index e606903..60a2c5e 100644
--- a/vl.c
+++ b/vl.c
@@ -3383,7 +3383,11 @@  static void qemu_event_increment(void)
     if (io_thread_fd == -1)
         return;
 
-    write(io_thread_fd, &byte, sizeof(byte));
+    if (write(io_thread_fd, &byte, sizeof(byte)) != sizeof(byte)){
+        fprintf(stderr, "qemu_event_increment: write() filed: %s\n",
+                strerror(errno));
+        exit (1);
+    }
 }
 
 static void qemu_event_read(void *opaque)
@@ -5767,7 +5771,8 @@  int main(int argc, char **argv, char **envp)
 #ifndef _WIN32
         if (daemonize) {
             uint8_t status = 1;
-            write(fds[1], &status, 1);
+            if (write(fds[1], &status, 1) != 1)
+                perror("write()");
         } else
 #endif
             fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno));
@@ -6064,7 +6069,8 @@  int main(int argc, char **argv, char **envp)
 	if (len != 1)
 	    exit(1);
 
-	chdir("/");
+	if (chdir("/"))
+        exit(1);
 	TFR(fd = qemu_open("/dev/null", O_RDWR));
 	if (fd == -1)
 	    exit(1);
@@ -6083,7 +6089,8 @@  int main(int argc, char **argv, char **envp)
             fprintf(stderr, "chroot failed\n");
             exit(1);
         }
-        chdir("/");
+        if (chdir("/"))
+            exit(1);
     }
 
     if (run_as) {