prefix.cpp

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/*
 * This file is part of the Code::Blocks IDE and licensed under the GNU General Public License, version 3
 * http://www.gnu.org/licenses/gpl-3.0.html
 *
 * $Revision: 5613 $
 * $Id: prefix.cpp 5613 2009-05-30 16:45:25Z killerbot $
 * $HeadURL: https://svn.code.sf.net/p/codeblocks/code/trunk/src/src/prefix.cpp $
 */

/*
 * BinReloc - a library for creating relocatable executables
 * Written by: Mike Hearn <mike@theoretic.com>
 *             Hongli Lai <h.lai@chello.nl>
 * http://autopackage.org/
 *
 * This source code is public domain. You can relicense this code
 * under whatever license you want.
 *
 * NOTE: if you're using C++ and are getting "undefined reference
 * to br_*", try renaming prefix.c to prefix.cpp
 */

/* WARNING, BEFORE YOU MODIFY PREFIX.C:
 *
 * If you make changes to any of the functions in prefix.c, you MUST
 * change the BR_NAMESPACE macro (in prefix.h).
 * This way you can avoid symbol table conflicts with other libraries
 * that also happen to use BinReloc.
 *
 * Example:
 * #define BR_NAMESPACE(funcName) foobar_ ## funcName
 * --> expands br_locate to foobar_br_locate
 */

#ifndef _PREFIX_C_
#define _PREFIX_C_

#ifdef HAVE_CONFIG_H
    #include "config.h"
#endif

#ifndef BR_PTHREADS
    /* Change 1 to 0 if you don't want pthread support */
    #define BR_PTHREADS 1
#endif /* BR_PTHREADS */

#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <string.h>
#include "prefix.h"

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */


#undef NULL
#define NULL ((void *) 0)

#ifdef __GNUC__
    #define br_return_val_if_fail(expr,val) if (!(expr)) {fprintf (stderr, "** BinReloc (%s): assertion %s failed\n", __PRETTY_FUNCTION__, #expr); return val;}
#else
    #define br_return_val_if_fail(expr,val) if (!(expr)) return val
#endif /* __GNUC__ */


#ifdef ENABLE_BINRELOC
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <unistd.h>


char *
br_locate (void *symbol)
{
    char line[5000];
    FILE *f;
    char *path;

    br_return_val_if_fail (symbol != NULL, (char*)NULL);

    f = fopen ("/proc/self/maps", "r");
    if (!f)
        return (char*)NULL;

    while (!feof (f))
    {
        unsigned long start, end;

        if (!fgets (line, sizeof (line), f))
            continue;
        if (!strstr (line, " r-xp ") || !strchr (line, '/'))
            continue;

        sscanf (line, "%lx-%lx ", &start, &end);
        if (symbol >= (void *) start && symbol < (void *) end)
        {
            char *tmp;
            size_t len;

            /* Extract the filename; it is always an absolute path */
            path = strchr (line, '/');

            /* Get rid of the newline */
            tmp = strrchr (path, '\n');
            if (tmp) *tmp = 0;

            /* Get rid of "(deleted)" */
            len = strlen (path);
            if (len > 10 && strcmp (path + len - 10, " (deleted)") == 0)
            {
                tmp = path + len - 10;
                *tmp = 0;
            }

            fclose(f);
            return strdup (path);
        }
    }

    fclose (f);
    return (char*)NULL;
}


char *
br_locate_prefix (void *symbol)
{
    char *path, *prefix;

    br_return_val_if_fail (symbol != NULL, (char*)NULL);

    path = br_locate (symbol);
    if (!path) return (char*)NULL;

    prefix = br_extract_prefix (path);
    free (path);
    return prefix;
}


char *
br_prepend_prefix (void *symbol, char *path)
{
    br_return_val_if_fail (symbol != 0, (char*)0);
    br_return_val_if_fail (path != 0, (char*)0);

    char* tmp = br_locate_prefix (symbol);
    if (!tmp) return (char*)0;

    char *newpath;
    if (strcmp (tmp, "/") == 0)
        newpath = strdup (path);
    else
        newpath = br_strcat (tmp, path);

    /* Get rid of compiler warning ("br_prepend_prefix never used") */
    if (0) br_prepend_prefix (0,  (char*)0);

    free (tmp);
    return newpath;
}

#endif /* ENABLE_BINRELOC */


/* Pthread stuff for thread safetiness */
#if BR_PTHREADS

#include <pthread.h>

static pthread_key_t br_thread_key;
#ifdef __FreeBSD__
static pthread_once_t br_thread_key_once = {0, (pthread_mutex_t)NULL};//PTHREAD_ONCE_INIT;
#else
static pthread_once_t br_thread_key_once = PTHREAD_ONCE_INIT;
#endif

static void
br_thread_local_store_fini ()
{
    char* specific = (char *) pthread_getspecific (br_thread_key);
    if (specific)
    {
        free (specific);
        pthread_setspecific (br_thread_key, NULL);
    }
    pthread_key_delete (br_thread_key);
    br_thread_key = 0;
}


static void
br_str_free (void *str)
{
    if (str)
        free (str);
}


static void
br_thread_local_store_init ()
{
    if (pthread_key_create (&br_thread_key, br_str_free) == 0)
        atexit (br_thread_local_store_fini);
}

#else /* BR_PTHREADS */

static char *br_last_value = (char *) NULL;

static void
br_free_last_value ()
{
    if (br_last_value)
        free (br_last_value);
}

#endif /* BR_PTHREADS */


const char *
br_thread_local_store (char *str)
{
    #if BR_PTHREADS
        pthread_once (&br_thread_key_once, br_thread_local_store_init);

        char* specific = (char *) pthread_getspecific (br_thread_key);
        br_str_free (specific);
        pthread_setspecific (br_thread_key, str);

    #else /* BR_PTHREADS */
        static int initialized = 0;

        if (!initialized)
        {
            atexit (br_free_last_value);
            initialized = 1;
        }

        if (br_last_value)
            free (br_last_value);
        br_last_value = str;
    #endif /* BR_PTHREADS */

    return (const char *) str;
}


char *
br_strcat (const char *str1, const char *str2)
{
    if (!str1) str1 = "";
    if (!str2) str2 = "";

    size_t len1 = strlen (str1);
    size_t len2 = strlen (str2);

    char* result = (char *) malloc (len1 + len2 + 1);
    memcpy (result, str1, len1);
    memcpy (result + len1, str2, len2);
    result[len1 + len2] = '\0';

    return result;
}


/* Emulates glibc's strndup() */
static char *
br_strndup (char *str, size_t size)
{
    br_return_val_if_fail (str != (char *) 0, (char *) 0);

    size_t len = strlen (str);
    if (!len) return strdup ("");
    if (size > len) size = len;

    char* result = (char *) calloc (sizeof (char), len + 1);
    memcpy (result, str, size);
    return result;
}


char *
br_extract_dir (const char *path)
{
    br_return_val_if_fail (path != (char *) 0, (char *) 0);

    const char* end = strrchr (path, '/');
    if (!end) return strdup (".");

    while (end > path && *end == '/')
    {
        end--;
    }
    char* result = br_strndup ((char *) path, end - path + 1);
    if (!*result)
    {
        free (result);
        return strdup ("/");
    } else
        return result;
}


char *
br_extract_prefix (const char *path)
{
    br_return_val_if_fail (path != (char *) 0, (char *) 0);

    if (!*path) return strdup ("/");
    const char* end = strrchr (path, '/');
    if (!end) return strdup (path);

    char* tmp = br_strndup ((char *) path, end - path);
    if (!*tmp)
    {
        free (tmp);
        return strdup ("/");
    }
    end = strrchr (tmp, '/');
    if (!end) return tmp;

    char* result = br_strndup (tmp, end - tmp);
    free (tmp);

    if (!*result)
    {
        free (result);
        result = strdup ("/");
    }

    return result;
}


#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* _PREFIX_C */