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Merge pull request #2047 from ashu-mehra/detect_docker
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Add support for detecting docker container
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@charliegracie
charliegracie authored Feb 27, 2018
2 parents 5fb191b + c398754 commit 4310e3a
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Showing 3 changed files with 136 additions and 43 deletions.
2 changes: 1 addition & 1 deletion port/common/omrport.c
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Original file line number Diff line number Diff line change
Expand Up @@ -261,7 +261,7 @@ static OMRPortLibrary MasterPortLibraryTable = {
omrsysinfo_cgroup_get_enabled_subsystems, /* sysinfo_cgroup_get_enabled_subsystems */
omrsysinfo_cgroup_enable_subsystems, /* sysinfo_cgroup_enable_subsystems */
omrsysinfo_cgroup_are_subsystems_enabled, /* sysinfo_cgroup_are_subsystems_enabled */
omrsysinfo_cgroup_get_memlimit, /* sysinfo_cgroup_get_memlimit */
omrsysinfo_cgroup_get_memlimit, /* sysinfo_cgroup_get_memlimit */
omrport_init_library, /* port_init_library */
omrport_startup_library, /* port_startup_library */
omrport_create_library, /* port_create_library */
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1 change: 1 addition & 0 deletions port/common/omrsysinfo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -902,6 +902,7 @@ omrsysinfo_cgroup_are_subsystems_enabled(struct OMRPortLibrary *portLibrary, uin
* omrsysinfo_cgroup_enable_limits() before calling this function.
* When the fuction returns OMRPORT_ERROR_SYSINFO_CGROUP_UNSUPPORTED_PLATFORM,
* value of *limits is unspecified.
* Note that 'limit' parameter must not be NULL.
*
* @param[in] portLibrary pointer to OMRPortLibrary
* @param[out] limit pointer to uint64_t which successful return contains memory limit imposed by cgroup
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176 changes: 134 additions & 42 deletions port/unix/omrsysinfo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -256,8 +256,17 @@ struct {
#if defined(LINUX)

#define OMR_CGROUP_V1_MOUNT_POINT "/sys/fs/cgroup"
#define ROOT_CGROUP "/"

/* Currently 12 subsystems/resource controllers are defined.
/* An entry in /proc/<pid>/cgroup is of following form:
* <hierarchy ID>:<subsystem>[,<subsystem>]*:<cgroup name>
*
* An example:
* 7:cpuacct,cpu:/mycgroup
*/
#define PROC_PID_CGROUP_ENTRY_FORMAT "%d:%[^:]:%s"

/* Currently 12 subsystems or resource controllers are defined.
*/
typedef enum OMRCgroupSubsystem {
INVALID_SUBSYSTEM = -1,
Expand Down Expand Up @@ -331,12 +340,14 @@ static uint16_t getPhysicalMemory();
#endif /* defined(OMRZTPF) */

#if defined(LINUX) && !defined(OMRZTPF)
static BOOLEAN isCgroupV1Available(struct OMRPortLibrary *portLibrary);
static void freeCgroupEntries(struct OMRPortLibrary *portLibrary, OMRCgroupEntry *cgEntryList);
static char * getCgroupNameForSubsystem(struct OMRPortLibrary *portLibrary, OMRCgroupEntry *cgEntryList, const char *subsystem);
static int32_t addCgroupEntry(struct OMRPortLibrary *portLibrary, OMRCgroupEntry **cgEntryList, int32_t hierId, const char *subsystem, const char *cgroupName);
static int32_t readCgroupFile(struct OMRPortLibrary *portLibrary, int pid, OMRCgroupEntry **cgroupEntryList, uint64_t *availableSubsystems);
static int32_t readCgroupFile(struct OMRPortLibrary *portLibrary, int pid, BOOLEAN inContainer, OMRCgroupEntry **cgroupEntryList, uint64_t *availableSubsystems);
static OMRCgroupSubsystem getCgroupSubsystemFromFlag(uint64_t subsystemFlag);
static int32_t readCgroupSubsystemFile(struct OMRPortLibrary *portLibrary, uint64_t subsystemFlag, const char *fileName, int32_t numItemsToRead, const char *format, ...);
static int32_t isRunningInContainer(struct OMRPortLibrary *portLibrary, BOOLEAN *inContainer);
#endif /* defined(LINUX) */


Expand Down Expand Up @@ -1701,7 +1712,7 @@ omrsysinfo_startup(struct OMRPortLibrary *portLibrary)
#if defined(LINUX) && !defined(OMRZTPF)
PPG_cgroupEntryList = NULL;
/* To handle the case where multiple port libraries are started and shutdown,
* as done by some fvtests (eg fvtest/porttest/j9portTest.cpp) that create fake portlibrary
* as done by some fvtests (eg fvtest/porttest/j9portTest.cpp) that create fake portlibrary
* to test its management and lifecycle,
* we need to ensure globals like cgroupEntryListMonitor are initialized and destroyed only once.
*/
Expand Down Expand Up @@ -3314,6 +3325,34 @@ omrsysinfo_os_kernel_info(struct OMRPortLibrary *portLibrary, struct OMROSKernel

#if defined(LINUX)

/**
* @internal
* Checks if cgroup v1 system is available
*
* @param[in] portLibrary pointer to OMRPortLibrary
*
* @return TRUE if cgroup v1 system is available, FALSE otherwise
*/
static BOOLEAN
isCgroupV1Available(struct OMRPortLibrary *portLibrary)
{
struct statfs buf = {0};
int32_t rc = 0;
BOOLEAN result = TRUE;

/* If tmpfs is mounted on /sys/fs/cgroup, then it indicates cgroup v1 system is available */
rc = statfs(OMR_CGROUP_V1_MOUNT_POINT, &buf);
if (0 != rc) {
portLibrary->error_set_last_error(portLibrary, errno, OMRPORT_ERROR_SYSINFO_SYS_FS_CGROUP_STATFS_FAILED);
result = FALSE;
} else if (TMPFS_MAGIC != buf.f_type) {
portLibrary->error_set_last_error_with_message_format(portLibrary, OMRPORT_ERROR_SYSINFO_SYS_FS_CGROUP_TMPFS_NOT_MOUNTED, "tmpfs is not mounted on " OMR_CGROUP_V1_MOUNT_POINT);
result = FALSE;
}

return result;
}

/**
* @internal
* Free resources allocated for OMRCgroupEntry
Expand Down Expand Up @@ -3420,21 +3459,20 @@ addCgroupEntry(struct OMRPortLibrary *portLibrary, OMRCgroupEntry **cgEntryList,
*
* @param[in] portLibrary pointer to OMRPortLibrary
* @param[in] pid process id
* @param[in] inContainer if set to TRUE then ignore cgroup in /proc/<pid>/cgroup and use ROOT_CGROUP instead
* @param[out] cgroupEntryList pointer to OMRCgroupEntry *. On successful return, *cgroupEntry
* points to a circular linked list. Each element of the list is populated based on the contents
* of /proc/<pid>/cgroup file.
* @param[out] availableSubsystems on successful return, contains bitwise-OR of flags of type OMR_CGROUP_SUBSYSTEMS_*
* @param[out] availableSubsystems on successful return, contains bitwise-OR of flags of type OMR_CGROUP_SUBSYSTEMS_*
* indicating the subsystems available for use
*
* returns 0 on success, negative code on error
*/
static int32_t
readCgroupFile(struct OMRPortLibrary *portLibrary, int pid, OMRCgroupEntry **cgroupEntryList, uint64_t *availableSubsystems)
readCgroupFile(struct OMRPortLibrary *portLibrary, int pid, BOOLEAN inContainer, OMRCgroupEntry **cgroupEntryList, uint64_t *availableSubsystems)
{
char cgroup[PATH_MAX];
char cgroupFilePath[PATH_MAX];
uintptr_t requiredSize = 0;
/* This array should be large enough to read names of all subsystems. 1024 should be enough. */
char subsystems[1024];
FILE *cgroupFile = NULL;
OMRCgroupEntry *cgEntryList = NULL;
uint64_t available = 0;
Expand All @@ -3444,34 +3482,29 @@ readCgroupFile(struct OMRPortLibrary *portLibrary, int pid, OMRCgroupEntry **cgr

requiredSize = portLibrary->str_printf(portLibrary, NULL, (uint32_t)-1, "/proc/%d/cgroup", pid);
Assert_PRT_true(requiredSize <= PATH_MAX);
portLibrary->str_printf(portLibrary, cgroup, sizeof(cgroup), "/proc/%d/cgroup", pid);
cgroupFile = fopen(cgroup, "r");
portLibrary->str_printf(portLibrary, cgroupFilePath, sizeof(cgroupFilePath), "/proc/%d/cgroup", pid);

/* Even if 'inContainer' is TRUE, we need to parse the cgroup file to get the list of subsystems */
cgroupFile = fopen(cgroupFilePath, "r");
if (NULL == cgroupFile) {
rc = portLibrary->error_set_last_error(portLibrary, errno, OMRPORT_ERROR_SYSINFO_PROCESS_CGROUP_FILE_FOPEN_FAILED);
goto _end;
}

while (0 == feof(cgroupFile)) {
char cgroup[PATH_MAX];
/* This array should be large enough to read names of all subsystems. 1024 should be enough based on current supported subsystems. */
char subsystems[1024];
char *cursor = NULL;
char *separator = NULL;
int32_t hierId = -1;

/* Following is the description of /proc/<pid>/cgroup copied from 'man' page for proc:
*
* Each entry in /proc/<pid>/cgroup is of type:
* 5:cpuacct,cpu,cpuset:/daemons
* The colon-separated fields are, from left to right:
* 1. hierarchy ID number
* 2. set of subsystems bound to the hierarchy
* 3. control group in the hierarchy to which the process belongs
*/
rc = fscanf(cgroupFile, "%d:%[^:]:%s", &hierId, subsystems, cgroup);
rc = fscanf(cgroupFile, PROC_PID_CGROUP_ENTRY_FORMAT, &hierId, subsystems, cgroup);
/* Ensure we didn't overflow */
Assert_PRT_true(strlen(subsystems) < 1024);
Assert_PRT_true(strlen(cgroup) < PATH_MAX);

if (EOF == rc) {
rc = 0;
break;
} else if (3 != rc) {
rc = portLibrary->error_set_last_error_with_message_format(portLibrary, OMRPORT_ERROR_SYSINFO_PROCESS_CGROUP_FILE_READ_FAILED, "unexpcted format of /proc/%d/cgroup file", pid);
Expand All @@ -3490,7 +3523,12 @@ readCgroupFile(struct OMRPortLibrary *portLibrary, int pid, OMRCgroupEntry **cgr
if (OMR_ARE_NO_BITS_SET(available, supportedSubsystems[i].flag)
&& !strcmp(cursor, supportedSubsystems[i].name)
) {
rc = addCgroupEntry(portLibrary, &cgEntryList, hierId, cursor, cgroup);
const char *cgroupToUse = cgroup;

if (TRUE == inContainer) {
cgroupToUse = ROOT_CGROUP;
}
rc = addCgroupEntry(portLibrary, &cgEntryList, hierId, cursor, cgroupToUse);
if (0 != rc) {
goto _end;
}
Expand Down Expand Up @@ -3617,6 +3655,63 @@ readCgroupSubsystemFile(struct OMRPortLibrary *portLibrary, uint64_t subsystemFl
return rc;
}

/**
* Checks if the process is running inside container
*
* @param[in] portLibrary pointer to OMRPortLibrary
* @param[out] inContainer pointer to BOOLEAN which on successful return indicates if the process is running in container or not
*
* @return 0 on success, otherwise negative error code
*/
static int32_t
isRunningInContainer(struct OMRPortLibrary *portLibrary, BOOLEAN *inContainer)
{
int32_t rc = 0;

/* Assume we are not in container */
*inContainer = FALSE;

if (isCgroupV1Available(portLibrary)) {
/* Read PID 1's cgroup file /proc/1/cgroup and check cgroup name for each subsystem.
* If cgroup name for each subsystem points to the root cgroup "/",
* then the process is not running in a container.
* For any other cgroup name, assume we are in a container.
*/
FILE *cgroupFile = fopen("/proc/1/cgroup", "r");

if (NULL == cgroupFile) {
rc = portLibrary->error_set_last_error(portLibrary, errno, OMRPORT_ERROR_SYSINFO_PROCESS_CGROUP_FILE_FOPEN_FAILED);
goto _end;
}

while (0 == feof(cgroupFile)) {
char cgroup[PATH_MAX];
char subsystems[1024];
int32_t hierId = -1;

rc = fscanf(cgroupFile, PROC_PID_CGROUP_ENTRY_FORMAT, &hierId, subsystems, cgroup);
/* Ensure we didn't overflow */
Assert_PRT_true(strlen(subsystems) < 1024);
Assert_PRT_true(strlen(cgroup) < PATH_MAX);

if (EOF == rc) {
break;
} else if (3 != rc) {
rc = portLibrary->error_set_last_error_with_message_format(portLibrary, OMRPORT_ERROR_SYSINFO_PROCESS_CGROUP_FILE_READ_FAILED, "unexpected format of /proc/1/cgroup file");
goto _end;
}

if (0 != strcmp(ROOT_CGROUP, cgroup)) {
*inContainer = TRUE;
break;
}
}
rc = 0;
}
_end:
return rc;
}

#endif /* defined(LINUX) */

BOOLEAN
Expand All @@ -3627,25 +3722,21 @@ omrsysinfo_cgroup_is_system_available(struct OMRPortLibrary *portLibrary)
int32_t rc = OMRPORT_ERROR_SYSINFO_CGROUP_UNSUPPORTED_PLATFORM;

if (NULL == PPG_cgroupEntryList) {
struct statfs buf = {0};
if (isCgroupV1Available(portLibrary)) {
BOOLEAN inContainer = FALSE;

/* If tmpfs is mounted on /sys/fs/cgroup, then it indicates cgroup v1 system is available */
rc = statfs(OMR_CGROUP_V1_MOUNT_POINT, &buf);
if (0 != rc) {
rc = portLibrary->error_set_last_error(portLibrary, errno, OMRPORT_ERROR_SYSINFO_SYS_FS_CGROUP_STATFS_FAILED);
goto _end;
} else if (TMPFS_MAGIC != buf.f_type) {
rc = portLibrary->error_set_last_error_with_message_format(portLibrary, OMRPORT_ERROR_SYSINFO_SYS_FS_CGROUP_TMPFS_NOT_MOUNTED, "tmpfs is not mounted on " OMR_CGROUP_V1_MOUNT_POINT);
goto _end;
}

omrthread_monitor_enter(cgroupEntryListMonitor);
if (NULL == PPG_cgroupEntryList) {
rc = readCgroupFile(portLibrary, getpid(), &PPG_cgroupEntryList, &PPG_cgroupSubsystemsAvailable);
}
omrthread_monitor_exit(cgroupEntryListMonitor);
if (0 != rc) {
goto _end;
rc = isRunningInContainer(portLibrary, &inContainer);
if (0 != rc) {
goto _end;
}
omrthread_monitor_enter(cgroupEntryListMonitor);
if (NULL == PPG_cgroupEntryList) {
rc = readCgroupFile(portLibrary, getpid(), inContainer, &PPG_cgroupEntryList, &PPG_cgroupSubsystemsAvailable);
}
omrthread_monitor_exit(cgroupEntryListMonitor);
if (0 != rc) {
goto _end;
}
}
} else {
rc = 0;
Expand Down Expand Up @@ -3720,13 +3811,14 @@ int32_t
omrsysinfo_cgroup_get_memlimit(struct OMRPortLibrary *portLibrary, uint64_t *limit)
{
int32_t rc = OMRPORT_ERROR_SYSINFO_CGROUP_UNSUPPORTED_PLATFORM;

Assert_PRT_true(NULL != limit);

#if defined(LINUX) && !defined(OMRZTPF)
uint64_t cgroupMemLimit = 0;
uint64_t physicalMemLimit = 0;
int32_t numItemsToRead = 1; /* memory.limit_in_bytes file contains only one integer value */

Assert_PRT_true(NULL != limit);

rc = readCgroupSubsystemFile(portLibrary, OMR_CGROUP_SUBSYSTEM_MEMORY, "memory.limit_in_bytes", numItemsToRead, "%lu", &cgroupMemLimit);

if (0 != rc) {
Expand Down

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