KVMOPEN(3) BSD Library Functions Manual KVMOPEN(3)

NAME
     kkvvmmooppeenn, kkvvmmooppeennffiilleess, kkvvmmcclloossee - initialize kernel virtual memory
     access

SYNOPSIS
     ##iinncclluuddee <>
     ##iinncclluuddee <>

     kvmt *
     kkvvmmooppeenn(const char *execfile, const char *corefile, char *swapfile,
         int flags, const char *errstr);

     kvmt *
     kkvvmmooppeennffiilleess(const char *execfile, const char *corefile, char *swapfile,
         int flags, char *errbuf);

     int
     kkvvmmcclloossee(kvmt *kd);

DESCRIPTION
     The functions kkvvmmooppeenn() and kkvvmmooppeennffiilleess() return a descriptor used to
     access kernel virtual memory via the kvm(3) library routines.  Both
     active kernels and crash dumps are accessible through this interface.

     execfile is the executable image of the kernel being examined.  This file
     must contain a symbol table.  If this argument is NULL, the currently
     running system is assumed, which is indicated by PATHUNIX in .

     corefile is the kernel memory device file.  It can be either /dev/mem or
     a crash dump core generated by savecore(8).  If corefile is NULL, the
     default indicated by PATHMEM from  is used.

     swapfile should indicate the swap device.  If NULL, PATHDRUM from
      is used.

     The flags argument indicates read/write access as in open(2) and applies
     only to the core file.  Only ORDONLY, OWRONLY, and ORDWR are permit-
     ted.

     There are two open routines which differ only with respect to the error
     mechanism.  One provides backward compatibility with the SunOS kvm
     library, while the other provides an improved error reporting framework.

     The kkvvmmooppeenn() function is the Sun kvm compatible open call.  Here, the
     errstr argument indicates how errors should be handled.  If it is NULL,
     no errors are reported and the application cannot know the specific
     nature of the failed kvm call.  If it is not NULL, errors are printed to
     stderr with errstr prepended to the message, as in perror(3).  Normally,
     the name of the program is used here.  The string is assumed to persist
     at least until the corresponding kkvvmmcclloossee() call.

     The kkvvmmooppeennffiilleess() function provides BSD style error reporting.  Here,
     error messages are not printed out by the library.  Instead, the applica-
     tion obtains the error message corresponding to the most recent kvm
     library call using kkvvmmggeetteerrrr() (see kvmgeterr(3) ). The results are
     undefined if the most recent kvm call did not produce an error.  Since
     kkvvmmggeetteerrrr() requires a kvm descriptor, but the open routines return NULL
     on failure, kkvvmmggeetteerrrr() cannot be used to get the error message if open
     fails.  Thus, kkvvmmooppeennffiilleess() will place any error message in the errbuf
     argument.  This buffer should be POSIX2LINEMAX characters large (from
     ).

RETURN VALUES
     The kkvvmmooppeenn() and kkvvmmooppeennffiilleess() functions both return a descriptor to
     be used in all subsequent kvm library calls.  The library is fully re-
     entrant.  On failure, NULL is returned, in which case kkvvmmooppeennffiilleess()
     writes the error message into errbuf.

     The kkvvmmcclloossee() function returns 0 on success and -1 on failure.

BUGS
     There should not be two open calls.  The ill-defined error semantics of
     the Sun library and the desire to have a backward-compatible library for
     BSD left little choice.

SEE ALSO
     open(2), kvm(3), kvmgetargv(3), kvmgetenvv(3), kvmgeterr(3),
     kvmgetprocs(3), kvmnlist(3), kvmread(3), kvmwrite(3)

BSD                             April 19, 1994                             BSD