source: bootcd/isolinux/syslinux-6.03/com32/lib/sys/module/elfutils.c

#include <stdlib.h>
#include <errno.h>

#include "elfutils.h"

unsigned long elf_hash(const unsigned char *name) {
        unsigned long h = 0;
        unsigned long g;

        while (*name) {
                h = (h << 4) + *name++;
                if ((g = h & 0xF0000000))
                        h ^= g >> 24;

                h &= ~g;
        }

        return h;
}

unsigned long elf_gnu_hash(const unsigned char *name) {
        unsigned long h = 5381;
        unsigned char c;

        for (c = *name; c != '\0'; c = *++name) {
                h = h * 33 + c;
        }

        return h & 0xFFFFFFFF;
}

#ifndef HAVE_ELF_POSIX_MEMALIGN

struct memalign_info {
        void    *start_addr;
        char    data[0];
};

int elf_malloc(void **memptr, size_t alignment, size_t size) {
        char *start_addr = NULL;
        struct memalign_info *info;

        if ((alignment & (alignment - 1)) != 0)
                return EINVAL;
        if (alignment % sizeof(void*) != 0)
                alignment = sizeof(void*);

        start_addr = malloc(size + (alignment > sizeof(struct memalign_info) ?
                                        alignment : sizeof(struct memalign_info)));

        if (start_addr == NULL)
                return ENOMEM;


        info = (struct memalign_info*)(start_addr -
                        ((unsigned long)start_addr % alignment) +
                        alignment - sizeof(struct memalign_info));

        info->start_addr = start_addr;

        *memptr = info->data;

        return 0;
}

void elf_free(char *memptr) {
        struct memalign_info *info = (struct memalign_info*)(memptr -
                        sizeof(struct memalign_info));

        free(info->start_addr);
}

#else

int elf_malloc(void **memptr, size_t alignment, size_t size) {
        if ((alignment & (alignment - 1)) != 0)
                return EINVAL;

        if (alignment % sizeof(void*) != 0)
                alignment = sizeof(void*);

        return posix_memalign(memptr, alignment, size);
}

void elf_free(void *memptr) {
        free(memptr);
}

#endif //HAVE_ELF_POSIX_MEMALIGN