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KVM_GETPROCS(3)        FreeBSD Library Functions Manual        KVM_GETPROCS(3)

     kvm_getprocs, kvm_getargv, kvm_getenvv -- access user process state

     Kernel Data Access Library (libkvm, -lkvm)

     #include <kvm.h>
     #include <sys/param.h>
     #include <sys/sysctl.h>
     #include <sys/user.h>

     struct kinfo_proc *
     kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt);

     char **
     kvm_getargv(kvm_t *kd, const struct kinfo_proc *p, int nchr);

     char **
     kvm_getenvv(kvm_t *kd, const struct kinfo_proc *p, int nchr);

     The kvm_getprocs() function returns a (sub-)set of active processes in
     the kernel indicated by kd.  The op and arg arguments constitute a predi-
     cate which limits the set of processes returned.  The value of op
     describes the filtering predicate as follows:

           KERN_PROC_ALL         all processes and kernel visible threads
           KERN_PROC_PROC        all processes, without threads
           KERN_PROC_PID         processes with process ID arg
           KERN_PROC_PGRP        processes with process group arg
           KERN_PROC_SESSION     processes with session arg
           KERN_PROC_TTY         processes with TTY arg
           KERN_PROC_UID         processes with effective user ID arg
           KERN_PROC_RUID        processes with real user ID arg
           KERN_PROC_INC_THREAD  modifier to return all kernel visible threads
                                 when filtering by process ID, process group,
                                 TTY, user ID, and real user ID

     The number of processes found is returned in the reference parameter cnt.
     The processes are returned as a contiguous array of kinfo_proc struc-
     tures.  This memory is locally allocated, and subsequent calls to
     kvm_getprocs() and kvm_close() will overwrite this storage.

     The kvm_getargv() function returns a null-terminated argument vector that
     corresponds to the command line arguments passed to process indicated by
     p.  Most likely, these arguments correspond to the values passed to
     exec(3) on process creation.  This information is, however, deliberately
     under control of the process itself.  Note that the original command name
     can be found, unaltered, in the p_comm field of the process structure
     returned by kvm_getprocs().

     The nchr argument indicates the maximum number of characters, including
     null bytes, to use in building the strings.  If this amount is exceeded,
     the string causing the overflow is truncated and the partial result is
     returned.  This is handy for programs like ps(1) and w(1) that print only
     a one line summary of a command and should not copy out large amounts of
     text only to ignore it.  If nchr is zero, no limit is imposed and all
     argument strings are returned in their entirety.

     The memory allocated to the argv pointers and string storage is owned by
     the kvm library.  Subsequent kvm_getprocs() and kvm_close(3) calls will
     clobber this storage.

     The kvm_getenvv() function is similar to kvm_getargv() but returns the
     vector of environment strings.  This data is also alterable by the

     The kvm_getprocs(), kvm_getargv(), and kvm_getenvv() functions return
     NULL on failure.

     kvm(3), kvm_close(3), kvm_geterr(3), kvm_nlist(3), kvm_open(3),
     kvm_openfiles(3), kvm_read(3), kvm_write(3)

     These routines do not belong in the kvm interface.

     In order for kvm_getenvv(3) to function correctly, procfs(5) must be
     mounted on /proc.

FreeBSD 6.2                   September 27, 2003                   FreeBSD 6.2


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