sys/sys/linker.h

	linker.h revision 199767f8919635c4928607450d9e0abb932109ce
/*-
 * Copyright (c) 1997-2000 Doug Rabson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */

#ifndef _SYS_LINKER_H_
#define _SYS_LINKER_H_

#ifdef _KERNEL

#include <machine/elf.h>
#include <sys/kobj.h>

#ifdef MALLOC_DECLARE
MALLOC_DECLARE(M_LINKER);
#endif

struct mod_depend;

/*
 * Object representing a file which has been loaded by the linker.
 */
typedef struct linker_file* linker_file_t;
typedef TAILQ_HEAD(, linker_file) linker_file_list_t;

typedef caddr_t linker_sym_t;       /* opaque symbol */
typedef c_caddr_t c_linker_sym_t;   /* const opaque symbol */
typedef int (*linker_function_name_callback_t)(const char *, void *);

/*
 * expanded out linker_sym_t
 */
typedef struct linker_symval {
    const char*     name;
    caddr_t     value;
    size_t      size;
} linker_symval_t;

typedef int (*linker_function_nameval_callback_t)(linker_file_t, int, linker_symval_t *, void *);

struct common_symbol {
    STAILQ_ENTRY(common_symbol) link;
    char*       name;
    caddr_t     address;
};

struct linker_file {
    KOBJ_FIELDS;
    int         refs;       /* reference count */
    int         userrefs;   /* kldload(2) count */
    int         flags;
#define LINKER_FILE_LINKED  0x1 /* file has been fully linked */
    TAILQ_ENTRY(linker_file) link;  /* list of all loaded files */
    char*       filename;   /* file which was loaded */
    char*       pathname;   /* file name with full path */
    int         id;     /* unique id */
    caddr_t     address;    /* load address */
    size_t      size;       /* size of file */
    caddr_t     ctors_addr; /* address of .ctors */
    size_t      ctors_size; /* size of .ctors */
    int         ndeps;      /* number of dependencies */
    linker_file_t*  deps;       /* list of dependencies */
    STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
    TAILQ_HEAD(, module) modules;   /* modules in this file */
    TAILQ_ENTRY(linker_file) loaded;    /* preload dependency support */
    int         loadcnt;    /* load counter value */

    /*
     * Function Boundary Tracing (FBT) or Statically Defined Tracing (SDT)
     * fields.
     */
    int         nenabled;   /* number of enabled probes. */
    int         fbt_nentries;   /* number of fbt entries created. */
};

/*
 * Object implementing a class of file (a.out, elf, etc.)
 */
typedef struct linker_class *linker_class_t;
typedef TAILQ_HEAD(, linker_class) linker_class_list_t;

struct linker_class {
    KOBJ_CLASS_FIELDS;
    TAILQ_ENTRY(linker_class) link; /* list of all file classes */
};

/*
 * Function type used when iterating over the list of linker files.
 */
typedef int linker_predicate_t(linker_file_t, void *);

/*
 * The "file" for the kernel.
 */
extern linker_file_t    linker_kernel_file;

/*
 * Obtain a reference to a module, loading it if required.
 */
int linker_reference_module(const char* _modname, struct mod_depend *_verinfo,
                linker_file_t* _result);

/*
 * Release a reference to a module, unloading it if there are no more
 * references.  Note that one should either provide a module name and
 * optional version info or a linker file, but not both.
 */
int linker_release_module(const char *_modname, struct mod_depend *_verinfo,
              linker_file_t _file);

/*
 * Iterate over all of the currently loaded linker files calling the
 * predicate function while the function returns 0.  Returns the value
 * returned by the last predicate function.
 */
int linker_file_foreach(linker_predicate_t *_predicate, void *_context);

/*
 * Lookup a symbol in a file.  If deps is TRUE, look in dependencies
 * if not found in file.
 */
caddr_t linker_file_lookup_symbol(linker_file_t _file, const char* _name,
                  int _deps);

/*
 * Lookup a linker set in a file.  Return pointers to the first entry,
 * last + 1, and count of entries.  Use: for (p = start; p < stop; p++) {}
 * void *start is really: "struct yoursetmember ***start;"
 */
int linker_file_lookup_set(linker_file_t _file, const char *_name,
               void *_start, void *_stop, int *_count);

/*
 * List all functions in a file.
 */
int linker_file_function_listall(linker_file_t,
                 linker_function_nameval_callback_t, void *);

/*
 * Functions soley for use by the linker class handlers.
 */
int linker_add_class(linker_class_t _cls);
int linker_file_unload(linker_file_t _file, int flags);
int linker_load_dependencies(linker_file_t _lf);
linker_file_t linker_make_file(const char* _filename, linker_class_t _cls);

/*
 * DDB Helpers, tuned specifically for ddb/db_kld.c
 */
int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
                 long *_diffp);
int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
int linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
                  long *offset);

/*
 * stack(9) helper for situations where kernel locking is required.
 */
int linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
    long *offset);


/* HWPMC helper */
void *linker_hwpmc_list_objects(void);

#endif  /* _KERNEL */

/*
 * Module information subtypes
 */
#define MODINFO_END     0x0000      /* End of list */
#define MODINFO_NAME        0x0001      /* Name of module (string) */
#define MODINFO_TYPE        0x0002      /* Type of module (string) */
#define MODINFO_ADDR        0x0003      /* Loaded address */
#define MODINFO_SIZE        0x0004      /* Size of module */
#define MODINFO_EMPTY       0x0005      /* Has been deleted */
#define MODINFO_ARGS        0x0006      /* Parameters string */
#define MODINFO_METADATA    0x8000      /* Module-specfic */

#define MODINFOMD_AOUTEXEC  0x0001      /* a.out exec header */
#define MODINFOMD_ELFHDR    0x0002      /* ELF header */
#define MODINFOMD_SSYM      0x0003      /* start of symbols */
#define MODINFOMD_ESYM      0x0004      /* end of symbols */
#define MODINFOMD_DYNAMIC   0x0005      /* _DYNAMIC pointer */
/* These values are MD on these two platforms */
#if !defined(__sparc64__) && !defined(__powerpc__)
#define MODINFOMD_ENVP      0x0006      /* envp[] */
#define MODINFOMD_HOWTO     0x0007      /* boothowto */
#define MODINFOMD_KERNEND   0x0008      /* kernend */
#endif
#define MODINFOMD_SHDR      0x0009      /* section header table */
#define MODINFOMD_CTORS_ADDR    0x000a      /* address of .ctors */
#define MODINFOMD_CTORS_SIZE    0x000b      /* size of .ctors */
#define MODINFOMD_FW_HANDLE 0x000c      /* Firmware dependent handle */
#define MODINFOMD_NOCOPY    0x8000      /* don't copy this metadata to the kernel */

#define MODINFOMD_DEPLIST   (0x4001 | MODINFOMD_NOCOPY) /* depends on */

#ifdef _KERNEL
#define MD_FETCH(mdp, info, type) ({ \
    type *__p; \
    __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
    __p ? *__p : 0; \
})
#endif

#define LINKER_HINTS_VERSION    1       /* linker.hints file version */
#define LINKER_HINTS_MAX    (1 << 20)   /* Allow at most 1MB for linker.hints */

#ifdef _KERNEL

/*
 * Module lookup
 */
extern vm_offset_t  preload_addr_relocate;
extern caddr_t      preload_metadata;

extern void *       preload_fetch_addr(caddr_t _mod);
extern size_t       preload_fetch_size(caddr_t _mod);
extern caddr_t      preload_search_by_name(const char *_name);
extern caddr_t      preload_search_by_type(const char *_type);
extern caddr_t      preload_search_next_name(caddr_t _base);
extern caddr_t      preload_search_info(caddr_t _mod, int _inf);
extern void     preload_delete_name(const char *_name);
extern void     preload_bootstrap_relocate(vm_offset_t _offset);

#ifdef KLD_DEBUG

extern int kld_debug;
#define KLD_DEBUG_FILE  1   /* file load/unload */
#define KLD_DEBUG_SYM   2   /* symbol lookup */

#define KLD_DPF(cat, args)                  \
    do {                            \
        if (kld_debug & KLD_DEBUG_##cat) printf args;   \
    } while (0)

#else

#define KLD_DPF(cat, args)

#endif

typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);

/* Support functions */
int elf_reloc(linker_file_t _lf, Elf_Addr base, const void *_rel, int _type, elf_lookup_fn _lu);
int elf_reloc_local(linker_file_t _lf, Elf_Addr base, const void *_rel, int _type, elf_lookup_fn _lu);
Elf_Addr elf_relocaddr(linker_file_t _lf, Elf_Addr addr);
const Elf_Sym *elf_get_sym(linker_file_t _lf, Elf_Size _symidx);
const char *elf_get_symname(linker_file_t _lf, Elf_Size _symidx);

typedef struct linker_ctf {
    const uint8_t   *ctftab;    /* Decompressed CTF data. */
    int         ctfcnt;     /* Number of CTF data bytes. */
    const Elf_Sym   *symtab;    /* Ptr to the symbol table. */
    int     nsym;       /* Number of symbols. */
    const char  *strtab;    /* Ptr to the string table. */
    int         strcnt;     /* Number of string bytes. */
    uint32_t    **ctfoffp;  /* Ptr to array of obj/fnc offsets. */
    uint32_t    **typoffp;  /* Ptr to array of type offsets. */
    long        *typlenp;   /* Ptr to number of type data entries. */
} linker_ctf_t;

int linker_ctf_get(linker_file_t, linker_ctf_t *);

int elf_cpu_load_file(linker_file_t);
int elf_cpu_unload_file(linker_file_t);

/* values for type */
#define ELF_RELOC_REL   1
#define ELF_RELOC_RELA  2

/*
 * This is version 1 of the KLD file status structure. It is identified
 * by its _size_ in the version field.
 */
struct kld_file_stat_1 {
    int     version;    /* set to sizeof(struct kld_file_stat_1) */
    char        name[MAXPATHLEN];
    int     refs;
    int     id;
    caddr_t address;    /* load address */
    size_t  size;       /* size in bytes */
};
#endif /* _KERNEL */

struct kld_file_stat {
    int     version;    /* set to sizeof(struct kld_file_stat) */
    char        name[MAXPATHLEN];
    int     refs;
    int     id;
    caddr_t address;    /* load address */
    size_t  size;       /* size in bytes */
    char        pathname[MAXPATHLEN];
};

struct kld_sym_lookup {
    int     version;    /* set to sizeof(struct kld_sym_lookup) */
    char    *symname;   /* Symbol name we are looking up */
    u_long  symvalue;
    size_t  symsize;
};
#define KLDSYM_LOOKUP   1

/*
 * Flags for kldunloadf() and linker_file_unload()
 */
#define LINKER_UNLOAD_NORMAL    0
#define LINKER_UNLOAD_FORCE 1

#ifndef _KERNEL

#include <sys/cdefs.h>

__BEGIN_DECLS
int kldload(const char* _file);
int kldunload(int _fileid);
int kldunloadf(int _fileid, int flags);
int kldfind(const char* _file);
int kldnext(int _fileid);
int kldstat(int _fileid, struct kld_file_stat* _stat);
int kldfirstmod(int _fileid);
int kldsym(int _fileid, int _cmd, void *_data);
__END_DECLS

#endif

#endif /* !_SYS_LINKER_H_ */