|
NAME
| |
allocmap, addseg, findseg, addrtoseg, addrtosegafter, removeseg,
freemap, get1, get2, get4, get8, put1, put2, put4, put8, rget,
rput, fpformat, locnone, locaddr, locconst, locreg, locindir,
loccmp, loceval, locfmt, locsimplify, lget1, lget2, lget4, lget8,
lput1, lput2, lput4, lput8 – machine-independent access to address
spaces and register sets
|
SYNOPSIS
| |
#include <u.h>
#include <libc.h>
#include <mach.h>
typedef struct Map Map;
typedef struct Seg Seg;
struct Seg
{
| |
char *name;
char *file;
int fd;
ulong base;
ulong size;
ulong offset;
int (*rw)(Map*, Seg*, ulong, void*, uint, int);
|
};
struct Map
{
};
Map *allocmap(void)
int addseg(Map *map, Seg seg)
int findseg(Map *map, char *name, char *file)
int addrtoseg(Map *map, ulong addr, Seg *seg)
int addrtosegafter(Map *map, ulong addr, Seg *seg)
void removeseg(Map *map, int i)
void freemap(Map *map)
int get1(Map *map, ulong addr, uchar *a, uint n)
int get2(Map *map, ulong addr, u16int *u)
int get4(Map *map, ulong addr, u32int *u)
int get8(Map *map, ulong addr, u64int *u)
int put1(Map *map, ulong addr, uchar *a, uint n)
int put2(Map *map, ulong addr, u16int u)
int put4(Map *map, ulong addr, u32int u)
int put8(Map *map, ulong addr, u64int u)
int rget(Regs *regs, char *reg, ulong *u)
int fpformat(Map *map, char *reg, char *a, uint n, char code);
int rput(Regs *regs, char *name, ulong u)
Loc locnone(void)
Loc locaddr(ulong addr)
Loc locconst(ulong con)
Loc locreg(char *reg)
Loc locindir(char *reg, long offset)
int loccmp(Loc *a, Loc *b)
int loceval(Map *map, Loc loc, ulong *addr)
int locfmt(Fmt *fmt)
int locsimplify(Map *map, Loc *regs, Loc loc, Loc *newloc)
int lget1(Map *map, Loc loc, uchar *a, uint n)
int lget2(Map *map, Loc loc, u16int *u)
int lget4(Map *map, Loc loc, u32int *u)
int lget8(Map *map, Loc loc, u64int *u)
int lput1(Map *map, Loc loc, uchar *a, uint n)
int lput2(Map *map, Loc loc, u16int u)
int lput4(Map *map, Loc loc, u32int u)
int lput8(Map *map, Loc loc, u64int u)
|
DESCRIPTION
| |
These functions provide a processor-independent interface for
accessing executable files, core files, and running processes
via maps, data structures that provides access to an address space
and register set. The functions described in mach-file(3) are
typically used to construct these maps. Related library functions
described in mach-symbol(3) provide similar access to symbol tables.
Each map comprises an optional register set and one or more segments,
each associating a non-overlapping range of memory addresses with
a logical section of an executable file or of a running process’s
address space. Other library functions then use a map and the
architecture-specific data structures to provide
a generic interface to the processor-dependent data.
Each segment has a name (e.g., text or data) and may be associated
with a particular file. A segment represents a range of accessible
address space. Segments may be backed an arbitary access function
(if the rw pointer is non-nil), or by the contents of an open
file (using the fd file descriptor). Each range has a
starting address in the space (base) and an extent (size). In
segments mapped by files, the range begins at byte offset in the
file. The rw function is most commonly used to provide access
to executing processes via ptrace(2) and to zeroed segments.
Allocmap creates an empty map; freemap frees a map.
Addseg adds the given segment to the map, resizing the map’s seg
array if necessary. A negative return value indicates an allocation
error.
Findseg returns the index of the segment with the given name (and,
if file is non-nil, the given file), or –1 if no such segment is
found.
Addrtoseg returns the index of the segment containing for the
given address, or –1 if that address is not mapped. Segments may
have overlapping address ranges: addseg appends segments to the
end of the seg array in the map, and addrtoseg searches the map
backwards from the end, so the most recently mapped
segment wins.
Addrtosegafter returns the index of the segment containing the
lowest mapped address greater than addr.
Removeseg removes the segment at the given index.
Get1, get2, get4, and get8 retrieve the data stored at address
addr in the address space associated with map. Get1 retrieves
n bytes of data beginning at addr into buf. Get2, get4 and get8
retrieve 16-bit, 32-bit and 64-bit values respectively, into the
location pointed to by u. The value is byte-swapped if the source
byte order differs from that of the current architecture. This
implies that the value returned by get2, get4, and get8 may not
be the same as the byte sequences returned by get1 when n is two,
four or eight; the former may be byte-swapped, the latter reflects
the byte order of the target architecture. These functions
return the number of bytes read or a –1 when there is an error.
Put1, put2, put4, and put8 write to the address space associated
with map. The address is translated using the map parameters and
multi-byte quantities are byte-swapped, if necessary, before they
are written. Put1 transfers n bytes stored at buf; put2, put4,
and put8 write the 16-bit, 32-bit or 64-bit quantity
contained in val, respectively. The number of bytes transferred
is returned. A –1 return value indicates an error.
When representing core files or running programs, maps also provide
access to the register set. Rget and rput read or write the register
named by reg. If the register is smaller than a ulong, the high
bits are ignored.
Fpformat converts the contents of a floating-point register to
a string. Buf is the address of a buffer of n bytes to hold the
resulting string. Code must be either F or f, selecting double
or single precision, respectively. If code is F, the contents
of the specified register and the following register are interpreted
as a
double-precision floating-point number; this is meaningful only
for architectures that implement double-precision floats by combining
adjacent single-precision registers.
A location represents a place in an executing image capable of
storing a value. Note that locations are typically passed by value
rather than by reference.
Locnone returns an unreadable, unwritable location. Locaddr returns
a location representing the memory address addr. Locreg returns
a location representing the register reg. Locindir returns an
location representing the memory address at offset added to the
value of reg. Locconst returns an imaginary unwritable
location holding the constant con; such locations are useful for
passing specific constants to functions expect locations, such
as unwind (see mach-stack(3)).
Loccmp compares two locations, returning negative, zero, or positive
values if *a is less than, equal to, or greater than *b, respectively.
Register locations are ordered before memory addresses, which
are ordered before indirections.
Locfmt is a print(3)-verb that formats a Loc structure (not a
pointer to one).
Indirection locations are needed in some contexts (e.g., when
using findlsym (see mach-symbol(3))), but bothersome in most.
Locsimplify rewrites indirections as absolute memory addresses,
by evaluating the register using the given map and adding the
offset.
The functions lget1, lget2, lget4, lget8, lput1, lput2, lput4,
and lput8 read and write the given locations, using the get, put,
rget, and rput function families as necessary.
|
SOURCE
| |
/usr/local/plan9/src/libmach
|
SEE ALSO
DIAGNOSTICS
| |
These routines set errstr.
|
BUGS
| |
This man page needs to describe Regs and Regdesc
|
|
|
