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dosfs: Fix race condition msdos_dir_read()

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Obtain file system instance lock before member access.

Close #2937.
This commit is contained in:
Sebastian Huber
2017-03-16 11:59:23 +01:00
parent 4c4869f483
commit 89164c67bc
1 changed files with 5 additions and 5 deletions
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10
cpukit/libfs/src/dosfs/msdos_dir.c
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@@ -88,6 +88,11 @@ msdos_dir_read(rtems_libio_t *iop, void *buffer, size_t count)
size_t string_size = sizeof(tmp_dirent.d_name); size_t string_size = sizeof(tmp_dirent.d_name);
bool is_first_entry; bool is_first_entry;
sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT,
MSDOS_VOLUME_SEMAPHORE_TIMEOUT);
if (sc != RTEMS_SUCCESSFUL)
rtems_set_errno_and_return_minus_one(EIO);
/* /*
* cast start and count - protect against using sizes that are not exact * cast start and count - protect against using sizes that are not exact
* multiples of the -dirent- size. These could result in unexpected * multiples of the -dirent- size. These could result in unexpected
@@ -107,11 +112,6 @@ msdos_dir_read(rtems_libio_t *iop, void *buffer, size_t count)
fat_fd->fat_file_size : fat_fd->fat_file_size :
fs_info->fat.vol.bpc; fs_info->fat.vol.bpc;
sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT,
MSDOS_VOLUME_SEMAPHORE_TIMEOUT);
if (sc != RTEMS_SUCCESSFUL)
rtems_set_errno_and_return_minus_one(EIO);
while (count > 0 && cmpltd >= 0) while (count > 0 && cmpltd >= 0)
{ {
/* /*