From 3ddee7f88aaf2dee38f7016ac8fd48dd9fdb43e3 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Tue, 24 Apr 2018 20:06:11 +0800 Subject: ALSA: Avoid using timespec for struct snd_pcm_status The struct snd_pcm_status will use 'timespec' type variables to record timestamp, which is not year 2038 safe on 32bits system. Userspace will use SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT as commands to issue ioctl() to fill the 'snd_pcm_status' structure in userspace. The command number is always defined through _IOR/_IOW/IORW, so when userspace changes the definition of 'struct timespec' to use 64-bit types, the command number also changes. Thus in the kernel, we now need to define two versions of each such ioctl and corresponding ioctl commands to handle 32bit time_t and 64bit time_t in native mode: struct snd_pcm_status32 { ...... s32 trigger_tstamp_sec; s32 trigger_tstamp_nsec; ...... s32 audio_tstamp_sec; s32 audio_tstamp_nsec; ...... }; struct snd_pcm_status64 { ...... s32 trigger_tstamp_sec; s32 trigger_tstamp_nsec; ...... s32 audio_tstamp_sec; s32 audio_tstamp_nsec; ...... }; Moreover in compat file, we renamed or introduced new structures to handle 32bit/64bit time_t in compatible mode. The 'struct snd_pcm_status32' and snd_pcm_status_user32() are used to handle 32bit time_t in compat mode. 'struct compat_snd_pcm_status64' and snd_pcm_status_user_compat64() are used to handle 64bit time_t. The implicit padding before timespec is made explicit to avoid incompatible structure layout between 32-bit and 64-bit x86 due to the different alignment requirements, and the snd_pcm_status structure is now hidden from the kernel to avoid relying on the timespec definitio definitionn Finally we can replace SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT with new commands and introduce new functions to fill new 'struct snd_pcm_status64' instead of using unsafe 'struct snd_pcm_status'. Then in future, the new commands can be matched when userspace changes 'timespec' to 64bit type to make a size change of 'struct snd_pcm_status'. When glibc changes time_t to 64-bit, any recompiled program will issue ioctl commands that the kernel does not understand without this patch. Signed-off-by: Baolin Wang Signed-off-by: Arnd Bergmann --- include/sound/pcm.h | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 54 insertions(+), 2 deletions(-) (limited to 'include/sound') diff --git a/include/sound/pcm.h b/include/sound/pcm.h index cb407fade933..5a31525e2df6 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -44,6 +44,7 @@ struct snd_pcm_hardware { size_t fifo_size; /* fifo size in bytes */ }; +struct snd_pcm_status64; struct snd_pcm_substream; struct snd_pcm_audio_tstamp_config; /* definitions further down */ @@ -558,8 +559,8 @@ int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree); int snd_pcm_info(struct snd_pcm_substream *substream, struct snd_pcm_info *info); int snd_pcm_info_user(struct snd_pcm_substream *substream, struct snd_pcm_info __user *info); -int snd_pcm_status(struct snd_pcm_substream *substream, - struct snd_pcm_status *status); +int snd_pcm_status64(struct snd_pcm_substream *substream, + struct snd_pcm_status64 *status); int snd_pcm_start(struct snd_pcm_substream *substream); int snd_pcm_stop(struct snd_pcm_substream *substream, snd_pcm_state_t status); int snd_pcm_drain_done(struct snd_pcm_substream *substream); @@ -1422,4 +1423,55 @@ static inline u64 pcm_format_to_bits(snd_pcm_format_t pcm_format) #define pcm_dbg(pcm, fmt, args...) \ dev_dbg((pcm)->card->dev, fmt, ##args) +struct snd_pcm_status64 { + snd_pcm_state_t state; /* stream state */ + u8 rsvd[4]; + s64 trigger_tstamp_sec; /* time when stream was started/stopped/paused */ + s64 trigger_tstamp_nsec; + s64 tstamp_sec; /* reference timestamp */ + s64 tstamp_nsec; + snd_pcm_uframes_t appl_ptr; /* appl ptr */ + snd_pcm_uframes_t hw_ptr; /* hw ptr */ + snd_pcm_sframes_t delay; /* current delay in frames */ + snd_pcm_uframes_t avail; /* number of frames available */ + snd_pcm_uframes_t avail_max; /* max frames available on hw since last status */ + snd_pcm_uframes_t overrange; /* count of ADC (capture) overrange detections from last status */ + snd_pcm_state_t suspended_state; /* suspended stream state */ + __u32 audio_tstamp_data; /* needed for 64-bit alignment, used for configs/report to/from userspace */ + s64 audio_tstamp_sec; /* sample counter, wall clock, PHC or on-demand sync'ed */ + s64 audio_tstamp_nsec; + s64 driver_tstamp_sec; /* useful in case reference system tstamp is reported with delay */ + s64 driver_tstamp_nsec; + __u32 audio_tstamp_accuracy; /* in ns units, only valid if indicated in audio_tstamp_data */ + unsigned char reserved[52-4*sizeof(s64)]; /* must be filled with zero */ +}; + +#define SNDRV_PCM_IOCTL_STATUS64 _IOR('A', 0x20, struct snd_pcm_status64) +#define SNDRV_PCM_IOCTL_STATUS_EXT64 _IOWR('A', 0x24, struct snd_pcm_status64) + +struct snd_pcm_status32 { + s32 state; /* stream state */ + s32 trigger_tstamp_sec; /* time when stream was started/stopped/paused */ + s32 trigger_tstamp_nsec; + s32 tstamp_sec; /* reference timestamp */ + s32 tstamp_nsec; + u32 appl_ptr; /* appl ptr */ + u32 hw_ptr; /* hw ptr */ + s32 delay; /* current delay in frames */ + u32 avail; /* number of frames available */ + u32 avail_max; /* max frames available on hw since last status */ + u32 overrange; /* count of ADC (capture) overrange detections from last status */ + s32 suspended_state; /* suspended stream state */ + u32 audio_tstamp_data; /* needed for 64-bit alignment, used for configs/report to/from userspace */ + s32 audio_tstamp_sec; /* sample counter, wall clock, PHC or on-demand sync'ed */ + s32 audio_tstamp_nsec; + s32 driver_tstamp_sec; /* useful in case reference system tstamp is reported with delay */ + s32 driver_tstamp_nsec; + u32 audio_tstamp_accuracy; /* in ns units, only valid if indicated in audio_tstamp_data */ + unsigned char reserved[52-4*sizeof(s32)]; /* must be filled with zero */ +}; + +#define SNDRV_PCM_IOCTL_STATUS32 _IOR('A', 0x20, struct snd_pcm_status32) +#define SNDRV_PCM_IOCTL_STATUS_EXT32 _IOWR('A', 0x24, struct snd_pcm_status32) + #endif /* __SOUND_PCM_H */ -- cgit