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ALSA: Avoid using timespec for struct snd_timer_status
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struct snd_timer_status uses 'timespec' type variables to record
timestamp, which will be changed to an incompatible layout with
updated user space using 64-bit time_t.

To handle both the old and the new layout on 32-bit architectures,
this patch introduces 'struct snd_timer_status32' and 'struct snd_timer_status64'
to handle 32bit time_t and 64bit time_t in native mode and compat mode,
which replaces timespec with s64 type.

When glibc changes time_t to 64-bit, any recompiled program will issue
ioctl commands that the kernel does not understand without this patch.

In the public uapi header, snd_timer_status is now guarded by
an #ifndef __KERNEL__ to avoid referencing 'struct timespec'.
The timespec definition will be removed from the kernel to prevent
new y2038 bugs and to avoid the conflict with an incompatible libc
type of the same name.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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@wangbaolin719 @arndb
wangbaolin719 authored and arndb committed Dec 11, 2019
1 parent fcae40c commit a07804c
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Showing 3 changed files with 64 additions and 57 deletions.
2 changes: 2 additions & 0 deletions include/uapi/sound/asound.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -761,6 +761,7 @@ struct snd_timer_params {
unsigned char reserved[60]; /* reserved */
};

#ifndef __KERNEL__
struct snd_timer_status {
struct timespec tstamp; /* Timestamp - last update */
unsigned int resolution; /* current period resolution in ns */
Expand All @@ -769,6 +770,7 @@ struct snd_timer_status {
unsigned int queue; /* used queue size */
unsigned char reserved[64]; /* reserved */
};
#endif

#define SNDRV_TIMER_IOCTL_PVERSION _IOR('T', 0x00, int)
#define SNDRV_TIMER_IOCTL_NEXT_DEVICE _IOWR('T', 0x01, struct snd_timer_id)
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62 changes: 56 additions & 6 deletions sound/core/timer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,30 @@ struct snd_timer_user {
struct mutex ioctl_lock;
};

struct snd_timer_status32 {
s32 tstamp_sec; /* Timestamp - last update */
s32 tstamp_nsec;
unsigned int resolution; /* current period resolution in ns */
unsigned int lost; /* counter of master tick lost */
unsigned int overrun; /* count of read queue overruns */
unsigned int queue; /* used queue size */
unsigned char reserved[64]; /* reserved */
};

#define SNDRV_TIMER_IOCTL_STATUS32 _IOR('T', 0x14, struct snd_timer_status32)

struct snd_timer_status64 {
s64 tstamp_sec; /* Timestamp - last update */
s64 tstamp_nsec;
unsigned int resolution; /* current period resolution in ns */
unsigned int lost; /* counter of master tick lost */
unsigned int overrun; /* count of read queue overruns */
unsigned int queue; /* used queue size */
unsigned char reserved[64]; /* reserved */
};

#define SNDRV_TIMER_IOCTL_STATUS64 _IOR('T', 0x14, struct snd_timer_status64)

/* list of timers */
static LIST_HEAD(snd_timer_list);

Expand Down Expand Up @@ -1875,17 +1899,41 @@ static int snd_timer_user_params(struct file *file,
return err;
}

static int snd_timer_user_status(struct file *file,
struct snd_timer_status __user *_status)
static int snd_timer_user_status32(struct file *file,
struct snd_timer_status32 __user *_status)
{
struct snd_timer_user *tu;
struct snd_timer_status32 status;

tu = file->private_data;
if (!tu->timeri)
return -EBADFD;
memset(&status, 0, sizeof(status));
status.tstamp_sec = tu->tstamp.tv_sec;
status.tstamp_nsec = tu->tstamp.tv_nsec;
status.resolution = snd_timer_resolution(tu->timeri);
status.lost = tu->timeri->lost;
status.overrun = tu->overrun;
spin_lock_irq(&tu->qlock);
status.queue = tu->qused;
spin_unlock_irq(&tu->qlock);
if (copy_to_user(_status, &status, sizeof(status)))
return -EFAULT;
return 0;
}

static int snd_timer_user_status64(struct file *file,
struct snd_timer_status64 __user *_status)
{
struct snd_timer_user *tu;
struct snd_timer_status status;
struct snd_timer_status64 status;

tu = file->private_data;
if (!tu->timeri)
return -EBADFD;
memset(&status, 0, sizeof(status));
status.tstamp = timespec64_to_timespec(tu->tstamp);
status.tstamp_sec = tu->tstamp.tv_sec;
status.tstamp_nsec = tu->tstamp.tv_nsec;
status.resolution = snd_timer_resolution(tu->timeri);
status.lost = tu->timeri->lost;
status.overrun = tu->overrun;
Expand Down Expand Up @@ -2009,8 +2057,10 @@ static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
return snd_timer_user_info(file, argp);
case SNDRV_TIMER_IOCTL_PARAMS:
return snd_timer_user_params(file, argp);
case SNDRV_TIMER_IOCTL_STATUS:
return snd_timer_user_status(file, argp);
case SNDRV_TIMER_IOCTL_STATUS32:
return snd_timer_user_status32(file, argp);
case SNDRV_TIMER_IOCTL_STATUS64:
return snd_timer_user_status64(file, argp);
case SNDRV_TIMER_IOCTL_START:
case SNDRV_TIMER_IOCTL_START_OLD:
return snd_timer_user_start(file);
Expand Down
57 changes: 6 additions & 51 deletions sound/core/timer_compat.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -69,54 +69,11 @@ static int snd_timer_user_info_compat(struct file *file,
return 0;
}

struct snd_timer_status32 {
struct compat_timespec tstamp;
u32 resolution;
u32 lost;
u32 overrun;
u32 queue;
unsigned char reserved[64];
};

static int snd_timer_user_status_compat(struct file *file,
struct snd_timer_status32 __user *_status)
{
struct snd_timer_user *tu;
struct snd_timer_status32 status;

tu = file->private_data;
if (!tu->timeri)
return -EBADFD;
memset(&status, 0, sizeof(status));
status.tstamp.tv_sec = tu->tstamp.tv_sec;
status.tstamp.tv_nsec = tu->tstamp.tv_nsec;
status.resolution = snd_timer_resolution(tu->timeri);
status.lost = tu->timeri->lost;
status.overrun = tu->overrun;
spin_lock_irq(&tu->qlock);
status.queue = tu->qused;
spin_unlock_irq(&tu->qlock);
if (copy_to_user(_status, &status, sizeof(status)))
return -EFAULT;
return 0;
}

#ifdef CONFIG_X86_X32
/* X32 ABI has the same struct as x86-64 */
#define snd_timer_user_status_x32(file, s) \
snd_timer_user_status(file, s)
#endif /* CONFIG_X86_X32 */

/*
*/

enum {
SNDRV_TIMER_IOCTL_GPARAMS32 = _IOW('T', 0x04, struct snd_timer_gparams32),
SNDRV_TIMER_IOCTL_INFO32 = _IOR('T', 0x11, struct snd_timer_info32),
SNDRV_TIMER_IOCTL_STATUS32 = _IOW('T', 0x14, struct snd_timer_status32),
#ifdef CONFIG_X86_X32
SNDRV_TIMER_IOCTL_STATUS_X32 = _IOW('T', 0x14, struct snd_timer_status),
#endif /* CONFIG_X86_X32 */
SNDRV_TIMER_IOCTL_STATUS_COMPAT32 = _IOW('T', 0x14, struct snd_timer_status32),
SNDRV_TIMER_IOCTL_STATUS_COMPAT64 = _IOW('T', 0x14, struct snd_timer_status64),
};

static long __snd_timer_user_ioctl_compat(struct file *file, unsigned int cmd,
Expand Down Expand Up @@ -145,12 +102,10 @@ static long __snd_timer_user_ioctl_compat(struct file *file, unsigned int cmd,
return snd_timer_user_gparams_compat(file, argp);
case SNDRV_TIMER_IOCTL_INFO32:
return snd_timer_user_info_compat(file, argp);
case SNDRV_TIMER_IOCTL_STATUS32:
return snd_timer_user_status_compat(file, argp);
#ifdef CONFIG_X86_X32
case SNDRV_TIMER_IOCTL_STATUS_X32:
return snd_timer_user_status_x32(file, argp);
#endif /* CONFIG_X86_X32 */
case SNDRV_TIMER_IOCTL_STATUS_COMPAT32:
return snd_timer_user_status32(file, argp);
case SNDRV_TIMER_IOCTL_STATUS_COMPAT64:
return snd_timer_user_status64(file, argp);
}
return -ENOIOCTLCMD;
}
Expand Down

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