![Gustavo A. R. Silva](/assets/img/avatar_default.png)
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare variable-length
types such as these ones is a flexible array member[1][2], introduced in
C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293
("cxgb3/l2t: Fix undefined behaviour")
Link: https://lore.kernel.org/r/20200224161406.GA21454@embeddedor
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
51 lines
1.3 KiB
C
51 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _SCSI_IOCTL_H
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#define _SCSI_IOCTL_H
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#define SCSI_IOCTL_SEND_COMMAND 1
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#define SCSI_IOCTL_TEST_UNIT_READY 2
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#define SCSI_IOCTL_BENCHMARK_COMMAND 3
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#define SCSI_IOCTL_SYNC 4 /* Request synchronous parameters */
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#define SCSI_IOCTL_START_UNIT 5
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#define SCSI_IOCTL_STOP_UNIT 6
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/* The door lock/unlock constants are compatible with Sun constants for
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the cdrom */
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#define SCSI_IOCTL_DOORLOCK 0x5380 /* lock the eject mechanism */
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#define SCSI_IOCTL_DOORUNLOCK 0x5381 /* unlock the mechanism */
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#define SCSI_REMOVAL_PREVENT 1
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#define SCSI_REMOVAL_ALLOW 0
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#ifdef __KERNEL__
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struct scsi_device;
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/*
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* Structures used for scsi_ioctl et al.
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*/
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typedef struct scsi_ioctl_command {
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unsigned int inlen;
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unsigned int outlen;
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unsigned char data[];
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} Scsi_Ioctl_Command;
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typedef struct scsi_idlun {
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__u32 dev_id;
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__u32 host_unique_id;
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} Scsi_Idlun;
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/* Fibre Channel WWN, port_id struct */
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typedef struct scsi_fctargaddress {
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__u32 host_port_id;
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unsigned char host_wwn[8]; // include NULL term.
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} Scsi_FCTargAddress;
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int scsi_ioctl_block_when_processing_errors(struct scsi_device *sdev,
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int cmd, bool ndelay);
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extern int scsi_ioctl(struct scsi_device *, int, void __user *);
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extern int scsi_compat_ioctl(struct scsi_device *sdev, int cmd, void __user *arg);
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#endif /* __KERNEL__ */
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#endif /* _SCSI_IOCTL_H */
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