PROCPS_MISC(3)

NAME
procps_misc - API for miscellaneous information in the /proc filesystem

SYNOPSIS
#include <libproc2/misc.h>

Platform Particulars

    long         procps_cpu_count (void);
    long         procps_hertz_get (void);
    unsigned int procps_pid_length (void);
    int          procps_linux_version (void);

Runtime Particulars

    int   procps_container_uptime (double *uptime_secs);
    int   procps_loadavg (double *av1, double *av5, double *av15);
    int   procps_uptime (double *uptime_secs, double *idle_secs);
    int   procps_uptime_snprint ( char *restrict str, size_t size, double uptime_secs, const int pretty);
    char *procps_uptime_sprint (void);
    char *procps_uptime_sprint_short (void);
    int   procps_users (void);

Namespace Particulars

    int         procps_ns_get_id (const char *name);
    const char *procps_ns_get_name (int id);
    int         procps_ns_read_pid (int pid, struct procps_ns *nsp);

Mask Name Resolving

    int procps_sigmask_names (char *const str, size_t size , const char *sigmask);
    int procps_capmask_names (char *const str, size_t size,  const char *capmask);

Link with -lproc2.

DESCRIPTION
procps_cpu_count() returns the number of CPUs that are currently online as sysconf(_SC_NPROCESSORS_ONLY) or an assumed 1.

procps_hertz_get() returns the number of clock ticks per second as sysconf(_SC_CLK_TCK) or an assumed 100. Dividing tics by this value yields seconds.

procps_pid_length() returns the maximum string length for a PID on the system. For example, if the largest possible PID value on was 123, then the length would be 3. If the file /proc/sys/kernel/pid_max is unreadable, the value is assumed to be 5.

procps_linux_version() returns the current Linux version as an encoded integer. On non-Linux systems that have an emulated proc filesystem this function returns the version of the Linux emulation instead. The version consists of three positive integers representing the major, minor and patch levels. The following macros are provided for encoding a given Linux version or separating out the components of the current version.

    LINUX_VERSION( major , minor , patch )

    LINUX_VERSION_MAJOR( ver )

    LINUX_VERSION_MINOR( ver )

    LINUX_VERSION_PATCH( ver )

procps_loadavg() fetches the system load average and puts the 1, 5 and 15 minute averages into location(s) specified by any pointer which is not NULL.

procps_container_uptime() returns the uptime of a container into location specified by the pointer if it is not NULL. This is currently determined by the elapsed time of PID 1, which could be given with the command:

    $ ps -o etimes 1
    ELAPSED
    12345

There is no concept of idle time in a container so procps_container_uptime() doesn't have that parameter.

procps_uptime() returns uptime and/or idle seconds into location(s) specified by any pointer which is not NULL. The sprint varieties return a human-readable string in one of two forms.

    HH:MM:SS up HH:MM, # users, load average: 1, 5, 15 MM averages

    up HH, MM

procps_uptime_snprint() Uses the given buffer str of size length to fill in the uptime string instead of a statically allocated buffer. The function requires the uptime_secs value, which can be obtained from procps_uptime() or procps_container_uptime() and the pretty flag determines if the output is standard or pretty/short.

procps_users() returns the number of users on the system. This value comes from sd_get_sessions(3) and counting the sessions of user, user-early and user-incomplete class or enumerating through getutent(3).

procps_ns_get_id() returns the integer id (enum namespace_type) of the namespace for the given namespace name.

procps_ns_get_name() returns the name of the namespace for the given id (enum namespace_type).

procps_ns_read_pid() returns the inodes for the namespaces of the given process in the procps_ns structure pointed to by nsp. Those inodes will appear in the order proscribed by enum namespace_type.

    enum namespace_type {
        PROCPS_NS_CGROUP,
        PROCPS_NS_IPC,
        PROCPS_NS_MNT,
        PROCPS_NS_NET,
        PROCPS_NS_PID,
        PROCPS_NS_TIME,
        PROCPS_NS_USER,
        PROCPS_NS_UTS
    };

procps_sigmask_names() Fills str with a human-readable text string of up to size bytes of the signals set in the hexadecimal signal mask sigmask, see signal(7). If the list of signals exceeds size bytes, the string will be truncated and will end with a '+'. It is up to the calling program to ensure that str is correctly allocated with at least size bytes.

procps_capmask_names() Fills str with a human-readable text string of up to size bytes of the capabilites set in the hexadecimal capability mask capmask, see capabilities(7). If the list of capabilities exceeds size bytes, the string will be truncated and will end with a '+'. It is up to the calling program to ensure that str is correctly allocated with at least size bytes.

For a process that has no capabilities or all capabilities the string will be "-" and "full" respectively.

RETURN VALUE

  Functions Returning an ‘int’ or ‘long’
An error will be indicated by a negative number that is always the inverse of some well known errno.h value.

  Functions Returning an ‘address’
An error will be indicated by a NULL return pointer with the reason found in the formal errno value.

FILES

/proc/loadavg
    The raw values for load average.

/proc/sys/kernel/osrelease
    Contains the release version of the Linux kernel or proc filesystem.

/proc/sys/kernel/pid_max
    Contains the value at which PIDs wrap around, one greater than the maximum PID value.

/proc/uptime
    The raw values for system uptime and idle time.

/proc/PID/ns
    contains the set of namespaces for a particular PID.

SEE ALSO
procps(3), procps_pids(3), getutent(3), sd_get_sessions(3), proc(5), capabilities(7), signal(7).