PATCH: dl_iterate_phdr()

[Alex Caudill <alex.caudill@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 329 bytes --]

Hi!

With a little help on IRC I hacked together a basic version of
dl_iterate_phdr(), which I dropped into src/ldso/dynlink.c in my tree.
This introduces a new include file: <link.h>

Line #9 of dl_iterate_phdr.c throws a warning that I'm not sure how to silence.

I've attached both, and a test program. No copyright.

Thanks!

[-- Attachment #2: dl_iterate_phdr.c --]
[-- Type: text/x-csrc, Size: 632 bytes --]

int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
{   
    struct dso *current;
    Ehdr *ehdr;
    struct dl_phdr_info info;
    int ret = 0;
    for(current = head; current; current = current->next) {
        ehdr = (Ehdr *)current->map;
        info.dlpi_addr = (ehdr->e_type == ET_EXEC) ? 0 : current->map;
        info.dlpi_name = current->shortname;
        info.dlpi_phdr = (Phdr *)(current->map + ehdr->e_phoff);
        info.dlpi_phnum = ehdr->e_phnum;

        ret = (callback)(&info, sizeof (info), data);
        if (ret != 0)
            break;
    }
    return ret;
}

[-- Attachment #3: link.h --]
[-- Type: text/x-chdr, Size: 480 bytes --]

#ifndef LINK_H
#define LINK_H

#include <elf.h>

#define __NEED_size_t
#include <bits/alltypes.h>

#ifdef _LP64
#define ElfW(type)      Elf64_ ## type
#else   
#define ElfW(type)      Elf32_ ## type
#endif

struct dl_phdr_info {
    ElfW(Addr)              dlpi_addr;  
    const char              *dlpi_name;
    const ElfW(Phdr)        *dlpi_phdr;
    ElfW(Half)              dlpi_phnum;
};
 
int dl_iterate_phdr(int (*)(struct dl_phdr_info *, size_t, void *), void *);

#endif

[-- Attachment #4: dltest.c --]
[-- Type: text/x-csrc, Size: 528 bytes --]

#define _GNU_SOURCE
#include <link.h>
#include <stdlib.h>
#include <stdio.h>

static int
callback(struct dl_phdr_info *info, size_t size, void *data)
{
    int j;

   printf("name=%s (%d segments)\n", info->dlpi_name,
        info->dlpi_phnum);

   for (j = 0; j < info->dlpi_phnum; j++)
         printf("\t\t header %2d: address=%10p\n", j,
             (void *) (info->dlpi_addr + info->dlpi_phdr[j].p_vaddr));
    return 0;
}

int
main(int argc, char *argv[])
{
    dl_iterate_phdr(callback, NULL);

   exit(EXIT_SUCCESS);
}