[Qemu-devel] [PATCH 0/2] pc_fw_add_pflash_drv() fixes

[Qemu-devel] [PATCH 0/2] pc_fw_add_pflash_drv() fixes

[Markus Armbruster]

Straightforward bug fixes, so they could qualify for 1.3.  But since
the bugs are fairly harmless, we might want to postpone to 1.4
regardless.  If we do, perhaps qemu-trivial could pick them up.

Markus Armbruster (2):
  pc_sysfw: Check for qemu_find_file() failure
  pc_sysfw: Plug memory leak on pc_fw_add_pflash_drv() error path

 hw/pc_sysfw.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

-- 
1.7.11.7

[Qemu-devel] [PATCH 1/2] pc_sysfw: Check for qemu_find_file() failure

[Markus Armbruster]

pc_fw_add_pflash_drv() ignores qemu_find_file() failure, and happily
creates a drive without a medium.

When pc_system_flash_init() asks for its size, bdrv_getlength() fails
with -ENOMEDIUM, which isn't checked either.  It fails relatively
cleanly only because -ENOMEDIUM isn't a multiple of 4096:

    $ qemu-system-x86_64 -S -vnc :0 -bios nonexistant
    qemu: PC system firmware (pflash) must be a multiple of 0x1000
    [Exit 1 ]

Fix by handling the qemu_find_file() failure.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 hw/pc_sysfw.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
index 9d7c5f4..066c4fe 100644
--- a/hw/pc_sysfw.c
+++ b/hw/pc_sysfw.c
@@ -84,6 +84,11 @@ static void pc_fw_add_pflash_drv(void)
         bios_name = BIOS_FILENAME;
     }
     filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
+    if (!filename) {
+        error_report("Can't open BIOS image %s: %s",
+                     bios_name, strerror(errno));
+        exit(1);
+    }
 
     opts = drive_add(IF_PFLASH, -1, filename, "readonly=on");
 
-- 
1.7.11.7

Re: [Qemu-devel] [Qemu-trivial] [PATCH 1/2] pc_sysfw: Check for qemu_find_file() failure

[Stefan Hajnoczi]

On Fri, Nov 23, 2012 at 07:12:17PM +0100, Markus Armbruster wrote:
> diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
> index 9d7c5f4..066c4fe 100644
> --- a/hw/pc_sysfw.c
> +++ b/hw/pc_sysfw.c
> @@ -84,6 +84,11 @@ static void pc_fw_add_pflash_drv(void)
>          bios_name = BIOS_FILENAME;
>      }
>      filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
> +    if (!filename) {
> +        error_report("Can't open BIOS image %s: %s",
> +                     bios_name, strerror(errno));

qemu_find_file() does not document that errno is set when returning
NULL.  I can't find other callers to qemu_find_file() that use errno
either.

Please add a doc comment to qemu_find_file() that errno will be set on
NULL return, otherwise we can't rely on it in the caller.

Stefan

Re: [Qemu-devel] [Qemu-trivial] [PATCH 1/2] pc_sysfw: Check for qemu_find_file() failure

[Markus Armbruster]

Stefan Hajnoczi <stefanha@gmail.com> writes:

> On Fri, Nov 23, 2012 at 07:12:17PM +0100, Markus Armbruster wrote:
>> diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
>> index 9d7c5f4..066c4fe 100644
>> --- a/hw/pc_sysfw.c
>> +++ b/hw/pc_sysfw.c
>> @@ -84,6 +84,11 @@ static void pc_fw_add_pflash_drv(void)
>>          bios_name = BIOS_FILENAME;
>>      }
>>      filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
>> +    if (!filename) {
>> +        error_report("Can't open BIOS image %s: %s",
>> +                     bios_name, strerror(errno));
>
> qemu_find_file() does not document that errno is set when returning
> NULL.  I can't find other callers to qemu_find_file() that use errno
> either.
>
> Please add a doc comment to qemu_find_file() that errno will be set on
> NULL return, otherwise we can't rely on it in the caller.

Good point, v2 coming.

[Qemu-devel] [PATCH v2 1/2] pc_sysfw: Check for qemu_find_file() failure

[Markus Armbruster]

pc_fw_add_pflash_drv() ignores qemu_find_file() failure, and happily
creates a drive without a medium.

When pc_system_flash_init() asks for its size, bdrv_getlength() fails
with -ENOMEDIUM, which isn't checked either.  It fails relatively
cleanly only because -ENOMEDIUM isn't a multiple of 4096:

    $ qemu-system-x86_64 -S -vnc :0 -bios nonexistant
    qemu: PC system firmware (pflash) must be a multiple of 0x1000
    [Exit 1 ]

Fix by handling the qemu_find_file() failure.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
v2: Don't report errno, because that can produce misleading error
messages.  For instance, when "seabios/out/bios.bin" is unreadable, we
fall back to $data_dir/seabios/out/bios.bin, which doesn't exist, and
then report "seabios/out/bios.bin: No such file or directory".  No other
caller reports errno.

 hw/pc_sysfw.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
index 9d7c5f4..a161e7b 100644
--- a/hw/pc_sysfw.c
+++ b/hw/pc_sysfw.c
@@ -84,6 +84,10 @@ static void pc_fw_add_pflash_drv(void)
         bios_name = BIOS_FILENAME;
     }
     filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
+    if (!filename) {
+        error_report("Can't open BIOS image %s", bios_name);
+        exit(1);
+    }
 
     opts = drive_add(IF_PFLASH, -1, filename, "readonly=on");
 
-- 
1.7.11.7

Re: [Qemu-devel] [PATCH v2 1/2] pc_sysfw: Check for qemu_find_file() failure

[Stefan Hajnoczi]

On Wed, Dec 05, 2012 at 03:28:05PM +0100, Markus Armbruster wrote:
> pc_fw_add_pflash_drv() ignores qemu_find_file() failure, and happily
> creates a drive without a medium.
> 
> When pc_system_flash_init() asks for its size, bdrv_getlength() fails
> with -ENOMEDIUM, which isn't checked either.  It fails relatively
> cleanly only because -ENOMEDIUM isn't a multiple of 4096:
> 
>     $ qemu-system-x86_64 -S -vnc :0 -bios nonexistant
>     qemu: PC system firmware (pflash) must be a multiple of 0x1000
>     [Exit 1 ]
> 
> Fix by handling the qemu_find_file() failure.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
> v2: Don't report errno, because that can produce misleading error
> messages.  For instance, when "seabios/out/bios.bin" is unreadable, we
> fall back to $data_dir/seabios/out/bios.bin, which doesn't exist, and
> then report "seabios/out/bios.bin: No such file or directory".  No other
> caller reports errno.
> 
>  hw/pc_sysfw.c | 4 ++++
>  1 file changed, 4 insertions(+)

Thanks, applied to the trivial patches tree:
https://github.com/stefanha/qemu/commits/trivial-patches

Stefan

[Qemu-devel] [PATCH 2/2] pc_sysfw: Plug memory leak on pc_fw_add_pflash_drv() error path

[Markus Armbruster]

Harmless, because we the error inevitably leads to another, fatal one
in pc_system_flash_init(): PC system firmware (pflash) not available.
Fix it anyway.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 hw/pc_sysfw.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
index 066c4fe..67fe87b 100644
--- a/hw/pc_sysfw.c
+++ b/hw/pc_sysfw.c
@@ -103,7 +103,9 @@ static void pc_fw_add_pflash_drv(void)
       return;
     }
 
-    drive_init(opts, machine->use_scsi);
+    if (!drive_init(opts, machine->use_scsi)) {
+        qemu_opts_del(opts);
+    }
 }
 
 static void pc_system_flash_init(MemoryRegion *rom_memory,
-- 
1.7.11.7

Re: [Qemu-devel] [PATCH 2/2] pc_sysfw: Plug memory leak on pc_fw_add_pflash_drv() error path

[Stefan Hajnoczi]

On Fri, Nov 23, 2012 at 07:12:18PM +0100, Markus Armbruster wrote:
> Harmless, because we the error inevitably leads to another, fatal one
> in pc_system_flash_init(): PC system firmware (pflash) not available.
> Fix it anyway.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  hw/pc_sysfw.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Thanks, applied to the trivial patches tree:
https://github.com/stefanha/qemu/commits/trivial-patches

Stefan