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 --- sound/core/pcm.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'sound/core/pcm.c') diff --git a/sound/core/pcm.c b/sound/core/pcm.c index 9a72d641743d..85db55ea49fd 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -443,7 +443,7 @@ static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry, { struct snd_pcm_substream *substream = entry->private_data; struct snd_pcm_runtime *runtime; - struct snd_pcm_status status; + struct snd_pcm_status64 status; int err; mutex_lock(&substream->pcm->open_mutex); @@ -453,17 +453,17 @@ static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry, goto unlock; } memset(&status, 0, sizeof(status)); - err = snd_pcm_status(substream, &status); + err = snd_pcm_status64(substream, &status); if (err < 0) { snd_iprintf(buffer, "error %d\n", err); goto unlock; } snd_iprintf(buffer, "state: %s\n", snd_pcm_state_name(status.state)); snd_iprintf(buffer, "owner_pid : %d\n", pid_vnr(substream->pid)); - snd_iprintf(buffer, "trigger_time: %ld.%09ld\n", - status.trigger_tstamp.tv_sec, status.trigger_tstamp.tv_nsec); - snd_iprintf(buffer, "tstamp : %ld.%09ld\n", - status.tstamp.tv_sec, status.tstamp.tv_nsec); + snd_iprintf(buffer, "trigger_time: %lld.%09lld\n", + status.trigger_tstamp_sec, status.trigger_tstamp_nsec); + snd_iprintf(buffer, "tstamp : %lld.%09lld\n", + status.tstamp_sec, status.tstamp_nsec); snd_iprintf(buffer, "delay : %ld\n", status.delay); snd_iprintf(buffer, "avail : %ld\n", status.avail); snd_iprintf(buffer, "avail_max : %ld\n", status.avail_max); -- cgit