Patchwork [12/14] linux-user/mmap.c: fix warnings with _FORTIFY_SOURCE

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Submitter Kirill A. Shutemov
Date Dec. 31, 2009, 1:34 a.m.
Message ID <1262223266-19191-3-git-send-email-kirill@shutemov.name>
Download mbox | patch
Permalink /patch/41957/
State New
Headers show

Comments

Kirill A. Shutemov - Dec. 31, 2009, 1:34 a.m.
CC    i386-linux-user/mmap.o
cc1: warnings being treated as errors
/usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c: In function 'mmap_frag':
/usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c:253: error: ignoring return value of 'pread', declared with attribute warn_unused_result
/usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c: In function 'target_mmap':
/usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c:477: error: ignoring return value of 'pread', declared with attribute warn_unused_result
make[1]: *** [mmap.o] Error 1

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
---
 linux-user/mmap.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
Arnaud Patard (Rtp) - Dec. 31, 2009, 10:50 a.m.
"Kirill A. Shutemov" <kirill@shutemov.name> writes:

Hi,

>   CC    i386-linux-user/mmap.o
> cc1: warnings being treated as errors
> /usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c: In function 'mmap_frag':
> /usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c:253: error: ignoring return value of 'pread', declared with attribute warn_unused_result
> /usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c: In function 'target_mmap':
> /usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c:477: error: ignoring return value of 'pread', declared with attribute warn_unused_result
> make[1]: *** [mmap.o] Error 1
>
> Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
> ---
>  linux-user/mmap.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
> index 144fb7c..e496c64 100644
> --- a/linux-user/mmap.c
> +++ b/linux-user/mmap.c
> @@ -250,7 +250,8 @@ static int mmap_frag(abi_ulong real_start,
>              mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
>  
>          /* read the corresponding file data */
> -        pread(fd, g2h(start), end - start, offset);
> +        if (pread(fd, g2h(start), end - start, offset) == -1)
> +            return -errno;

This needs to be checked but iirc, it's wrong. One should set errno and
return -1. Please double check and fix if needed.

Thanks,
Arnaud
Kirill A. Shutemov - Jan. 2, 2010, 2:09 a.m.
On Thu, Dec 31, 2009 at 12:50 PM, Arnaud Patard
<arnaud.patard@rtp-net.org> wrote:
> "Kirill A. Shutemov" <kirill@shutemov.name> writes:
>
> Hi,
>
>>   CC    i386-linux-user/mmap.o
>> cc1: warnings being treated as errors
>> /usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c: In function 'mmap_frag':
>> /usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c:253: error: ignoring return value of 'pread', declared with attribute warn_unused_result
>> /usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c: In function 'target_mmap':
>> /usr/src/RPM/BUILD/qemu-0.11.92/linux-user/mmap.c:477: error: ignoring return value of 'pread', declared with attribute warn_unused_result
>> make[1]: *** [mmap.o] Error 1
>>
>> Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
>> ---
>>  linux-user/mmap.c |    6 ++++--
>>  1 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
>> index 144fb7c..e496c64 100644
>> --- a/linux-user/mmap.c
>> +++ b/linux-user/mmap.c
>> @@ -250,7 +250,8 @@ static int mmap_frag(abi_ulong real_start,
>>              mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
>>
>>          /* read the corresponding file data */
>> -        pread(fd, g2h(start), end - start, offset);
>> +        if (pread(fd, g2h(start), end - start, offset) == -1)
>> +            return -errno;
>
> This needs to be checked but iirc, it's wrong. One should set errno and
> return -1. Please double check and fix if needed.

Thanks.

Patch

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 144fb7c..e496c64 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -250,7 +250,8 @@  static int mmap_frag(abi_ulong real_start,
             mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
 
         /* read the corresponding file data */
-        pread(fd, g2h(start), end - start, offset);
+        if (pread(fd, g2h(start), end - start, offset) == -1)
+            return -errno;
 
         /* put final protection */
         if (prot_new != (prot1 | PROT_WRITE))
@@ -474,7 +475,8 @@  abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
                                   -1, 0);
             if (retaddr == -1)
                 goto fail;
-            pread(fd, g2h(start), len, offset);
+            if (pread(fd, g2h(start), len, offset) == -1)
+                return -errno;
             if (!(prot & PROT_WRITE)) {
                 ret = target_mprotect(start, len, prot);
                 if (ret != 0) {