refclock_phc: open device for writing with extpps option

In version 6.15 the Linux kernel started checking write access on the
PHC file descriptor in the PTP_PIN_SETFUNC and PTP_EXTTS_REQUEST ioctls.
chronyd opened the PHC device as readonly, which caused the PHC refclock
driver configured with the extpps option to fail with the
"Could not enable external PHC timestamping" error message.

To ensure compatibility with new kernel versions, add flags to the
SYS_Linux_OpenPHC() function and open the device with the O_RDWR flag
when the extpps option is enabled.
This commit is contained in:
Miroslav Lichvar
2025-08-07 14:04:22 +02:00
parent b365edb48e
commit f78e4681ef
4 changed files with 17 additions and 16 deletions

View File

@@ -39,7 +39,7 @@ extern void SYS_Linux_EnableSystemCallFilter(int level, SYS_ProcessContext conte
extern int SYS_Linux_CheckKernelVersion(int req_major, int req_minor);
extern int SYS_Linux_OpenPHC(const char *device);
extern int SYS_Linux_OpenPHC(const char *device, int flags);
extern int SYS_Linux_GetPHCReadings(int fd, int nocrossts, int *reading_mode, int max_readings,
struct timespec tss[][3]);