osdElfFindAddr.c File Reference

#include <unistd.h>
#include <dlfcn.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <elf.h>
#include <errno.h>
#include <inttypes.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include "epicsMutex.h"
#include "epicsThread.h"
#include "epicsTime.h"
#include "errlog.h"
#include "epicsStackTrace.h"
#include "epicsStackTracePvt.h"

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Classes
union	Ehdr_
union	Shdr_
union	Sym_
struct	MMap_
struct	ESyms_

Macros
#define	FIND_ADDR_DEBUG   0
#define	FLD(c, s, f)   (ELFCLASS32==c ? s.e32.f : s.e64.f )
#define	ARR(c, s, i, f)   (ELFCLASS32==c ? s.e32[i].f : s.e64[i].f)

Typedefs
typedef union Ehdr_	Ehdr
typedef union Shdr_	Shdr
typedef union Sym_	Sym
typedef struct MMap_ *	MMap
typedef struct ESyms_ *	ESyms

Functions
LIBCOM_API void	ClockTime_GetProgramStart (epicsTimeStamp *pDest)
int	epicsFindAddr (void *addr, epicsSymbol *sym_p)
int	epicsFindAddrGetFeatures (void)

Macro Definition Documentation

#define ARR	(		c,
			s,
			i,
			f
	)		(ELFCLASS32==c ? s.e32[i].f : s.e64[i].f)

Definition at line 49 of file osdElfFindAddr.c.

#define FIND_ADDR_DEBUG   0

Definition at line 36 of file osdElfFindAddr.c.

#define FLD	(		c,
			s,
			f
	)		(ELFCLASS32==c ? s.e32.f : s.e64.f )

Definition at line 48 of file osdElfFindAddr.c.

Typedef Documentation

typedef union Ehdr_ Ehdr

typedef struct ESyms_ * ESyms

typedef struct MMap_ * MMap

typedef union Shdr_ Shdr

typedef union Sym_ Sym

Function Documentation

LIBCOM_API void ClockTime_GetProgramStart

(

epicsTimeStamp *

pDest

)

int epicsFindAddr	(	void *	addr,
		epicsSymbol *	sym_p
	)

Definition at line 518 of file osdElfFindAddr.c.

{
    Dl_info    inf;
    ESyms      es,nes = 0;
    uintptr_t  minoff,off;
    size_t     i;
    Sym        sym;
    Sym        nearest;
    const char *strtab;
    uint8_t    c;
    size_t     idx;

    if ( ! dladdr(addr, &inf) || (!inf.dli_fname && !inf.dli_sname) ) {
        sym_p->f_nam = 0;
        sym_p->s_nam = 0;
        /* unable to lookup   */
        return 0;
    }

    sym_p->f_nam = inf.dli_fname;

    /* If the symbol is in the main executable then solaris' dladdr returns bogus info */
#ifndef __sun
    if ( (sym_p->s_nam = inf.dli_sname) ) {
        sym_p->s_val = inf.dli_saddr;
        /* Have a symbol name - just use it and be done */
        return 0;
    }
#endif

    /* No symbol info; try to access ELF file and ready symbol table from there */

    elfsLockWrite();

    /* See if we have loaded this file already */
    es = elfSymsFind(inf.dli_fname);

    if ( !es ) {

        elfsUnlockWrite();

        if ( ! (nes = elfRead(inf.dli_fname, (uintptr_t)inf.dli_fbase)) )  {
            /* this path can only be taken if there is no memory for '*nes' */
            return 0;
        }

        elfsLockWrite();

        /* Has someone else intervened and already added this file while we were reading ? */
        es = elfSymsFind(inf.dli_fname);

        if ( es ) {
            /* will undo our work in the unlikely event... */
        } else {
            nes->next = elfs;
            es  = elfs = nes;
            nes = 0;
        }
    }

    elfsUnlockWrite();

    /* Undo our work in the unlikely event that it was redundant */
    if ( nes )
        elfSymsDestroy( nes );

    nearest.raw = 0;
    minoff      = (uintptr_t)-1LL;

    if ( es->nsyms ) {
        c       = es->eclss;
        sym.raw = (char*)es->symMap->addr + es->symMap->off;
        strtab  = (char*)es->strMap->addr + es->strMap->off;

        /* Do a brute-force search through the symbol table; if this is executed
         * very often then it would be worthwhile constructing a sorted list of
         * symbol addresses but for the stack trace we don't care...
         */
#if (FIND_ADDR_DEBUG & 1)
        printf("Looking for %p\n", addr);
#endif

        if ( ELFCLASS32 == c ) {
            for ( i=0; i<es->nsyms; i++ ) {
                if ( STT_FUNC != ELF32_ST_TYPE(sym.e32[i].st_info) )
                    continue;
                /* don't bother about undefined symbols */
                if ( 0 == sym.e32[i].st_shndx )
                    continue;
#if (FIND_ADDR_DEBUG & 1)
                printf("Trying: %s (0x%lx)\n", strtab + sym.e32[i].st_name, (unsigned long)(sym.e32[i].st_value + es->addr));
#endif
                if ( (uintptr_t)addr >= (uintptr_t)sym.e32[i].st_value + es->addr ) {
                    off = (uintptr_t)addr - ((uintptr_t)sym.e32[i].st_value + es->addr);
                    if ( off < minoff ) {
                        minoff      = off;
                        nearest.e32 = &sym.e32[i];
                    }
                }
            }
        } else {
            for ( i=0; i<es->nsyms; i++ ) {
                if ( STT_FUNC != ELF64_ST_TYPE(sym.e64[i].st_info) )
                    continue;
                /* don't bother about undefined symbols */
                if ( 0 == sym.e64[i].st_shndx )
                    continue;
#if (FIND_ADDR_DEBUG & 1)
                printf("Trying: %s (0x%llx)\n", strtab + sym.e64[i].st_name, (unsigned long long)(sym.e64[i].st_value + es->addr));
#endif
                if ( (uintptr_t)addr >= (uintptr_t)sym.e64[i].st_value + es->addr ) {
                    off = (uintptr_t)addr - ((uintptr_t)sym.e64[i].st_value + es->addr);
                    if ( off < minoff ) {
                        minoff      = off;
                        nearest.e64 = &sym.e64[i];
                    }
                }
            }
        }
    }

    if ( nearest.raw && ( (idx = ARR(c,nearest,0,st_name)) < es->strMap->max ) ) {
        sym_p->s_nam = strtab + idx;
        sym_p->s_val = (char*) ARR(c, nearest, 0, st_value) + es->addr;
    }

    return 0;
}

int epicsFindAddrGetFeatures

(

void

)

Definition at line 647 of file osdElfFindAddr.c.

{
    /* The static information given here may not be correct;
     * it also depends on
     *  - compilation (frame pointer optimization)
     *  - linkage (static vs. dynamic)
     *  - stripping
     */
    return  EPICS_STACKTRACE_LCL_SYMBOLS
          | EPICS_STACKTRACE_GBL_SYMBOLS
          | EPICS_STACKTRACE_DYN_SYMBOLS;
}