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36 .\" @(#)kvm_open.3 8.3 (Berkeley) 4/19/94
46 .Nd initialize kernel virtual memory access
50 .Fd #include <fcntl.h>
53 .Fn kvm_open "const char *execfile" "const char *corefile" "const char *swapfile" "int flags" "const char *errstr"
55 .Fn kvm_openfiles "const char *execfile" "const char *corefile" "const char *swapfile" "int flags" "char *errbuf"
57 .Fn kvm_close "kvm_t *kd"
63 return a descriptor used to access kernel virtual memory
66 library routines. Both active kernels and crash dumps are accessible
67 through this interface.
70 is the executable image of the kernel being examined.
71 This file must contain a symbol table.
74 the currently running system is assumed,
79 is the kernel memory device file. It can be either /dev/mem
80 or a crash dump core generated by
86 the default indicated by
88 from <paths.h> is used.
91 should indicate the swap device. If
94 from <paths.h> is used.
98 argument indicates read/write access as in
100 and applies only to the core file.
108 There are two open routines which differ only with respect to
110 One provides backward compatibility with the SunOS kvm library, while the
111 other provides an improved error reporting framework.
115 function is the Sun kvm compatible open call. Here, the
117 argument indicates how errors should be handled. If it is
119 no errors are reported and the application cannot know the
120 specific nature of the failed kvm call.
123 errors are printed to stderr with
125 prepended to the message, as in
127 Normally, the name of the program is used here.
128 The string is assumed to persist at least until the corresponding
134 function provides BSD style error reporting.
135 Here, error messages are not printed out by the library.
136 Instead, the application obtains the error message
137 corresponding to the most recent kvm library call using
141 The results are undefined if the most recent kvm call did not produce
145 requires a kvm descriptor, but the open routines return
149 cannot be used to get the error message if open fails.
152 will place any error message in the
154 argument. This buffer should be _POSIX2_LINE_MAX characters large (from
161 functions both return a descriptor to be used
162 in all subsequent kvm library calls.
163 The library is fully re-entrant.
166 is returned, in which case
168 writes the error message into
173 function returns 0 on success and -1 on failure.
175 There should not be two open calls. The ill-defined error semantics
176 of the Sun library and the desire to have a backward-compatible library
177 for BSD left little choice.