gentoo-projects/pax-utils/scanelf.c

/*
 * Copyright 2003-2005 Gentoo Foundation
 * Distributed under the terms of the GNU General Public License v2
 * $Header: /var/cvsroot/gentoo-projects/pax-utils/scanelf.c,v 1.81 2005/06/13 03:35:41 vapier Exp $
 *
 ********************************************************************
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <libgen.h>
#include <limits.h>
#define __USE_GNU
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/stat.h>
#include <dirent.h>
#include <getopt.h>
#include <assert.h>
#include "paxelf.h"

static const char *rcsid = "$Id: scanelf.c,v 1.81 2005/06/13 03:35:41 vapier Exp $";
#define argv0 "scanelf"

#define IS_MODIFIER(c) (c == '%' || c == '#')


/* prototypes */
static void scanelf_file(const char *filename);
static void scanelf_dir(const char *path);
static void scanelf_ldpath();
static void scanelf_envpath();
static void usage(int status);
static void parseargs(int argc, char *argv[]);
static char *xstrdup(const char *s);
static void *xmalloc(size_t size);
static void xstrcat(char **dst, const char *src, size_t *curr_len);
static inline void xchrcat(char **dst, const char append, size_t *curr_len);

/* variables to control behavior */
static char *ldpaths[256];
static char scan_ldpath = 0;
static char scan_envpath = 0;
static char scan_symlink = 1;
static char dir_recurse = 0;
static char dir_crossmount = 1;
static char show_pax = 0;
static char show_phdr = 0;
static char show_textrel = 0;
static char show_rpath = 0;
static char show_needed = 0;
static char show_interp = 0;
static char show_bind = 0;
static char show_textrels = 0;
static char show_banner = 1;
static char be_quiet = 0;
static char be_verbose = 0;
static char be_wewy_wewy_quiet = 0;
static char *find_sym = NULL, *versioned_symname = NULL;
static char *find_lib = NULL;
static char *out_format = NULL;
static char *search_path = NULL;


/* sub-funcs for scanelf_file() */
static void scanelf_file_get_symtabs(elfobj *elf, void **sym, void **tab)
{
        /* find the best SHT_DYNSYM and SHT_STRTAB sections */
#define GET_SYMTABS(B) \
        if (elf->elf_class == ELFCLASS ## B) { \
                Elf ## B ## _Shdr *symtab, *strtab, *dynsym, *dynstr; \
                /* debug sections */ \
                symtab = SHDR ## B (elf_findsecbyname(elf, ".symtab")); \
                strtab = SHDR ## B (elf_findsecbyname(elf, ".strtab")); \
                /* runtime sections */ \
                dynsym = SHDR ## B (elf_findsecbyname(elf, ".dynsym")); \
                dynstr = SHDR ## B (elf_findsecbyname(elf, ".dynstr")); \
                if (symtab && dynsym) { \
                        *sym = (void*)((EGET(symtab->sh_size) > EGET(dynsym->sh_size)) ? symtab : dynsym); \
                } else { \
                        *sym = (void*)(symtab ? symtab : dynsym); \
                } \
                if (strtab && dynstr) { \
                        *tab = (void*)((EGET(strtab->sh_size) > EGET(dynstr->sh_size)) ? strtab : dynstr); \
                } else { \
                        *tab = (void*)(strtab ? strtab : dynstr); \
                } \
        }
        GET_SYMTABS(32)
        GET_SYMTABS(64)
}
static char *scanelf_file_pax(elfobj *elf, char *found_pax)
{
        static char *paxflags;
        static char ret[7];
        unsigned long i, shown;

        if (!show_pax) return NULL;

        shown = 0;
        memset(&ret, 0, sizeof(ret));

        if (elf->phdr) {
#define SHOW_PAX(B) \
        if (elf->elf_class == ELFCLASS ## B) { \
        Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
        Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
        for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                if (EGET(phdr[i].p_type) != PT_PAX_FLAGS) \
                        continue; \
                if (be_quiet && (EGET(phdr[i].p_flags) == 10240)) \
                        continue; \
                memcpy(ret, pax_short_pf_flags(EGET(phdr[i].p_flags)), 6); \
                *found_pax = 1; \
                ++shown; \
                break; \
        } \
        }
        SHOW_PAX(32)
        SHOW_PAX(64)
        }

        /* fall back to EI_PAX if no PT_PAX was found */
        if (!*ret) {
                paxflags = pax_short_hf_flags(EI_PAX_FLAGS(elf));
                if (!be_quiet || (be_quiet && EI_PAX_FLAGS(elf))) {
                        *found_pax = 1;
                        return paxflags;
                }
                strncpy(ret, paxflags, sizeof(ret));
        }

        if (be_quiet && !shown)
                return NULL;
        return ret;

}
static char *scanelf_file_phdr(elfobj *elf, char *found_phdr, char *found_relro, char *found_load)
{
        static char ret[12];
        char *found;
        unsigned long i, off, shown, check_flags;
        unsigned char multi_stack, multi_relro, multi_load;

        if (!show_phdr) return NULL;

        memcpy(ret, "--- --- ---\0", 12);

        shown = 0;
        multi_stack = multi_relro = multi_load = 0;

        if (elf->phdr) {
#define SHOW_PHDR(B) \
        if (elf->elf_class == ELFCLASS ## B) { \
        Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
        Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
        uint32_t flags; \
        for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                if (EGET(phdr[i].p_type) == PT_GNU_STACK) { \
                        if (multi_stack++) warnf("%s: multiple PT_GNU_STACK's !?", elf->filename); \
                        found = found_phdr; \
                        off = 0; \
                        check_flags = PF_X; \
                } else if (EGET(phdr[i].p_type) == PT_GNU_RELRO) { \
                        if (multi_relro++) warnf("%s: multiple PT_GNU_RELRO's !?", elf->filename); \
                        found = found_relro; \
                        off = 4; \
                        check_flags = PF_X; \
                } else if (EGET(phdr[i].p_type) == PT_LOAD) { \
                        if (multi_load++ > 2) warnf("%s: more than 2 PT_LOAD's !?", elf->filename); \
                        found = found_load; \
                        off = 8; \
                        check_flags = PF_W|PF_X; \
                } else \
                        continue; \
                flags = EGET(phdr[i].p_flags); \
                if (be_quiet && ((flags & check_flags) != check_flags)) \
                        continue; \
                memcpy(ret+off, gnu_short_stack_flags(flags), 3); \
                *found = 1; \
                ++shown; \
        } \
        }
        SHOW_PHDR(32)
        SHOW_PHDR(64)
        }

        if (be_quiet && !shown)
                return NULL;
        else
                return ret;
}
static char *scanelf_file_textrel(elfobj *elf, char *found_textrel)
{
        static char ret[] = "TEXTREL";
        unsigned long i;

        if (!show_textrel && !show_textrels) return NULL;

        if (elf->phdr) {
#define SHOW_TEXTREL(B) \
        if (elf->elf_class == ELFCLASS ## B) { \
        Elf ## B ## _Dyn *dyn; \
        Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
        Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
        Elf ## B ## _Off offset; \
        for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                if (EGET(phdr[i].p_type) != PT_DYNAMIC) continue; \
                offset = EGET(phdr[i].p_offset); \
                if (offset >= elf->len - sizeof(Elf ## B ## _Dyn)) continue; \
                dyn = DYN ## B (elf->data + offset); \
                while (EGET(dyn->d_tag) != DT_NULL) { \
                        if (EGET(dyn->d_tag) == DT_TEXTREL) { /*dyn->d_tag != DT_FLAGS)*/ \
                                *found_textrel = 1; \
                                /*if (dyn->d_un.d_val & DF_TEXTREL)*/ \
                                return (be_wewy_wewy_quiet ? NULL : ret); \
                        } \
                        ++dyn; \
                } \
        } }
        SHOW_TEXTREL(32)
        SHOW_TEXTREL(64)
        }

        if (be_quiet || be_wewy_wewy_quiet)
                return NULL;
        else
                return (char *)"   -   ";
}
static char *scanelf_file_textrels(elfobj *elf, char *found_textrels, char *found_textrel)
{
        unsigned long s, r, rmax;
        void *symtab_void, *strtab_void, *text_void;

        if (!show_textrels) return NULL;

        /* don't search for TEXTREL's if the ELF doesn't have any */
        if (!*found_textrel) scanelf_file_textrel(elf, found_textrel);
        if (!*found_textrel) return NULL;

        scanelf_file_get_symtabs(elf, &symtab_void, &strtab_void);
        text_void = elf_findsecbyname(elf, ".text");

        if (symtab_void && strtab_void && text_void && elf->shdr) {
#define SHOW_TEXTRELS(B) \
        if (elf->elf_class == ELFCLASS ## B) { \
        Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
        Elf ## B ## _Shdr *shdr = SHDR ## B (elf->shdr); \
        Elf ## B ## _Shdr *symtab = SHDR ## B (symtab_void); \
        Elf ## B ## _Shdr *strtab = SHDR ## B (strtab_void); \
        Elf ## B ## _Shdr *text = SHDR ## B (text_void); \
        Elf ## B ## _Addr vaddr = EGET(text->sh_addr); \
        uint ## B ## _t memsz = EGET(text->sh_size); \
        Elf ## B ## _Rel *rel; \
        Elf ## B ## _Rela *rela; \
        /* search the section headers for relocations */ \
        for (s = 0; s < EGET(ehdr->e_shnum); ++s) { \
                uint32_t sh_type = EGET(shdr[s].sh_type); \
                if (sh_type == SHT_REL) { \
                        rel = REL ## B (elf->data + EGET(shdr[s].sh_offset)); \
                        rela = NULL; \
                        rmax = EGET(shdr[s].sh_size) / sizeof(*rel); \
                } else if (sh_type == SHT_RELA) { \
                        rel = NULL; \
                        rela = RELA ## B (elf->data + EGET(shdr[s].sh_offset)); \
                        rmax = EGET(shdr[s].sh_size) / sizeof(*rela); \
                } else \
                        continue; \
                /* now see if any of the relocs are in the .text */ \
                for (r = 0; r < rmax; ++r) { \
                        unsigned long sym_max; \
                        Elf ## B ## _Addr offset_tmp; \
                        Elf ## B ## _Sym *func; \
                        Elf ## B ## _Sym *sym; \
                        Elf ## B ## _Addr r_offset; \
                        uint ## B ## _t r_info; \
                        if (sh_type == SHT_REL) { \
                                r_offset = EGET(rel[r].r_offset); \
                                r_info = EGET(rel[r].r_info); \
                        } else { \
                                r_offset = EGET(rela[r].r_offset); \
                                r_info = EGET(rela[r].r_info); \
                        } \
                        /* make sure this relocation is inside of the .text */ \
                        if (r_offset < vaddr || r_offset >= vaddr + memsz) { \
                                if (be_verbose <= 2) continue; \
                        } else \
                                *found_textrels = 1; \
                        /* locate this relocation symbol name */ \
                        sym = SYM ## B (elf->data + EGET(symtab->sh_offset)); \
                        sym_max = ELF ## B ## _R_SYM(r_info); \
                        if (sym_max * EGET(symtab->sh_entsize) < symtab->sh_size) \
                                sym += sym_max; \
                        else \
                                sym = NULL; \
                        sym_max = EGET(symtab->sh_size) / EGET(symtab->sh_entsize); \
                        /* show the raw details about this reloc */ \
                        printf("\tTEXTREL %s: ", elf->base_filename); \
                        if (sym && sym->st_name) \
                                printf("%s", (char*)(elf->data + EGET(strtab->sh_offset) + EGET(sym->st_name))); \
                        else \
                                printf("(NULL: fake?)"); \
                        printf(" [0x%lX]", (unsigned long)r_offset); \
                        /* now try to find the closest symbol that this rel is probably in */ \
                        sym = SYM ## B (elf->data + EGET(symtab->sh_offset)); \
                        func = NULL; \
                        offset_tmp = 0; \
                        while (sym_max--) { \
                                if (EGET(sym->st_value) < r_offset && EGET(sym->st_value) > offset_tmp) { \
                                        func = sym; \
                                        offset_tmp = EGET(sym->st_value); \
                                } \
                                ++sym; \
                        } \
                        printf(" in "); \
                        if (func && func->st_name) \
                                printf("%s", (char*)(elf->data + EGET(strtab->sh_offset) + EGET(func->st_name))); \
                        else \
                                printf("(NULL: fake?)"); \
                        printf(" [0x%lX]\n", (unsigned long)offset_tmp); \
                } \
        } }
        SHOW_TEXTRELS(32)
        SHOW_TEXTRELS(64)
        }
        if (!*found_textrels)
                warnf("ELF %s has TEXTREL markings but doesnt appear to have any real TEXTREL's !?", elf->filename);

        return NULL;
}
static void scanelf_file_rpath(elfobj *elf, char *found_rpath, char **ret, size_t *ret_len)
{
        unsigned long i, s;
        char *rpath, *runpath, **r;
        void *strtbl_void;

        if (!show_rpath) return;

        strtbl_void = elf_findsecbyname(elf, ".dynstr");
        rpath = runpath = NULL;

        if (elf->phdr && strtbl_void) {
#define SHOW_RPATH(B) \
                if (elf->elf_class == ELFCLASS ## B) { \
                Elf ## B ## _Dyn *dyn; \
                Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
                Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
                Elf ## B ## _Shdr *strtbl = SHDR ## B (strtbl_void); \
                Elf ## B ## _Off offset; \
                Elf ## B ## _Xword word; \
                /* Scan all the program headers */ \
                for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                        /* Just scan dynamic headers */ \
                        if (EGET(phdr[i].p_type) != PT_DYNAMIC) continue; \
                        offset = EGET(phdr[i].p_offset); \
                        if (offset >= elf->len - sizeof(Elf ## B ## _Dyn)) continue; \
                        /* Just scan dynamic RPATH/RUNPATH headers */ \
                        dyn = DYN ## B (elf->data + offset); \
                        while ((word=EGET(dyn->d_tag)) != DT_NULL) { \
                                if (word == DT_RPATH) { \
                                        r = &rpath; \
                                } else if (word == DT_RUNPATH) { \
                                        r = &runpath; \
                                } else { \
                                        ++dyn; \
                                        continue; \
                                } \
                                /* Verify the memory is somewhat sane */ \
                                offset = EGET(strtbl->sh_offset) + EGET(dyn->d_un.d_ptr); \
                                if (offset < (Elf ## B ## _Off)elf->len) { \
                                        if (*r) warn("ELF has multiple %s's !?", get_elfdtype(word)); \
                                        *r = (char*)(elf->data + offset); \
                                        /* If quiet, don't output paths in ld.so.conf */ \
                                        if (be_quiet) { \
                                                size_t len; \
                                                char *start, *end; \
                                                /* note that we only 'chop' off leading known paths. */ \
                                                /* since *r is read-only memory, we can only move the ptr forward. */ \
                                                start = *r; \
                                                /* scan each path in : delimited list */ \
                                                while (start) { \
                                                        end = strchr(start, ':'); \
                                                        len = (end ? abs(end - start) : strlen(start)); \
                                                        for (s = 0; ldpaths[s]; ++s) { \
                                                                if (!strncmp(ldpaths[s], start, len) && !ldpaths[s][len]) { \
                                                                        *r = (end ? end + 1 : NULL); \
                                                                        break; \
                                                                } \
                                                        } \
                                                        if (!*r || !ldpaths[s] || !end) \
                                                                start = NULL; \
                                                        else \
                                                                start = start + len + 1; \
                                                } \
                                        } \
                                        if (*r) *found_rpath = 1; \
                                } \
                                ++dyn; \
                        } \
                } }
                SHOW_RPATH(32)
                SHOW_RPATH(64)
        }

        if (be_wewy_wewy_quiet) return;

        if (rpath && runpath) {
                if (!strcmp(rpath, runpath)) {
                        xstrcat(ret, runpath, ret_len);
                } else {
                        fprintf(stderr, "RPATH [%s] != RUNPATH [%s]\n", rpath, runpath);
                        xchrcat(ret, '{', ret_len);
                        xstrcat(ret, rpath, ret_len);
                        xchrcat(ret, ',', ret_len);
                        xstrcat(ret, runpath, ret_len);
                        xchrcat(ret, '}', ret_len);
                }
        } else if (rpath || runpath)
                xstrcat(ret, (runpath ? runpath : rpath), ret_len);
        else if (!be_quiet)
                xstrcat(ret, "  -  ", ret_len);
}
static char *scanelf_file_needed_lib(elfobj *elf, char *found_needed, char *found_lib, int op, char **ret, size_t *ret_len)
{
        unsigned long i;
        char *needed;
        void *strtbl_void;

        if ((op==0 && !show_needed) || (op==1 && !find_lib)) return NULL;

        strtbl_void = elf_findsecbyname(elf, ".dynstr");

        if (elf->phdr && strtbl_void) {
#define SHOW_NEEDED(B) \
                if (elf->elf_class == ELFCLASS ## B) { \
                Elf ## B ## _Dyn *dyn; \
                Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
                Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
                Elf ## B ## _Shdr *strtbl = SHDR ## B (strtbl_void); \
                Elf ## B ## _Off offset; \
                for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                        if (EGET(phdr[i].p_type) != PT_DYNAMIC) continue; \
                        offset = EGET(phdr[i].p_offset); \
                        if (offset >= elf->len - sizeof(Elf ## B ## _Dyn)) continue; \
                        dyn = DYN ## B (elf->data + offset); \
                        while (EGET(dyn->d_tag) != DT_NULL) { \
                                if (EGET(dyn->d_tag) == DT_NEEDED) { \
                                        offset = EGET(strtbl->sh_offset) + EGET(dyn->d_un.d_ptr); \
                                        if (offset >= (Elf ## B ## _Off)elf->len) { \
                                                ++dyn; \
                                                continue; \
                                        } \
                                        needed = (char*)(elf->data + offset); \
                                        if (op == 0) { \
                                                if (!be_wewy_wewy_quiet) { \
                                                        if (*found_needed) xchrcat(ret, ',', ret_len); \
                                                        xstrcat(ret, needed, ret_len); \
                                                } \
                                                *found_needed = 1; \
                                        } else { \
                                                if (!strcmp(find_lib, needed)) { \
                                                        *found_lib = 1; \
                                                        return (be_wewy_wewy_quiet ? NULL : find_lib); \
                                                } \
                                        } \
                                } \
                                ++dyn; \
                        } \
                } }
                SHOW_NEEDED(32)
                SHOW_NEEDED(64)
        }

        return NULL;
}
static char *scanelf_file_interp(elfobj *elf, char *found_interp)
{
        void *strtbl_void;

        if (!show_interp) return NULL;

        strtbl_void = elf_findsecbyname(elf, ".interp");

        if (strtbl_void) {
#define SHOW_INTERP(B) \
                if (elf->elf_class == ELFCLASS ## B) { \
                        Elf ## B ## _Shdr *strtbl = SHDR ## B (strtbl_void); \
                        *found_interp = 1; \
                        return (be_wewy_wewy_quiet ? NULL : elf->data + EGET(strtbl->sh_offset)); \
                }
                SHOW_INTERP(32)
                SHOW_INTERP(64)
        }
        return NULL;
}
static char *scanelf_file_bind(elfobj *elf, char *found_bind)
{
        unsigned long i;
        struct stat s;

        if (!show_bind) return NULL;
        if (!elf->phdr) return NULL;

#define SHOW_BIND(B) \
        if (elf->elf_class == ELFCLASS ## B) { \
                Elf ## B ## _Dyn *dyn; \
                Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
                Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
                Elf ## B ## _Off offset; \
                for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                        if (EGET(phdr[i].p_type) != PT_DYNAMIC) continue; \
                        offset = EGET(phdr[i].p_offset); \
                        if (offset >= elf->len - sizeof(Elf ## B ## _Dyn)) continue; \
                        dyn = DYN ## B (elf->data + offset); \
                        while (EGET(dyn->d_tag) != DT_NULL) { \
                                if (EGET(dyn->d_tag) == DT_BIND_NOW || \
                                   (EGET(dyn->d_tag) == DT_FLAGS && EGET(dyn->d_un.d_val) & DF_BIND_NOW)) \
                                { \
                                        if (be_quiet) return NULL; \
                                        *found_bind = 1; \
                                        return (char *)(be_wewy_wewy_quiet ? NULL : "NOW"); \
                                } \
                                ++dyn; \
                        } \
                } \
        }
        SHOW_BIND(32)
        SHOW_BIND(64)

        if (be_wewy_wewy_quiet) return NULL;

        if (be_quiet && !fstat(elf->fd, &s) && !(s.st_mode & S_ISUID || s.st_mode & S_ISGID)) {
                return NULL;
        } else {
                *found_bind = 1;
                return (char *) "LAZY";
        }
}
static char *scanelf_file_sym(elfobj *elf, char *found_sym)
{
        unsigned long i;
        void *symtab_void, *strtab_void;

        if (!find_sym) return NULL;

        scanelf_file_get_symtabs(elf, &symtab_void, &strtab_void);

        if (symtab_void && strtab_void) {
#define FIND_SYM(B) \
                if (elf->elf_class == ELFCLASS ## B) { \
                Elf ## B ## _Shdr *symtab = SHDR ## B (symtab_void); \
                Elf ## B ## _Shdr *strtab = SHDR ## B (strtab_void); \
                Elf ## B ## _Sym *sym = SYM ## B (elf->data + EGET(symtab->sh_offset)); \
                unsigned long cnt = EGET(symtab->sh_size) / EGET(symtab->sh_entsize); \
                char *symname; \
                for (i = 0; i < cnt; ++i) { \
                        if (sym->st_name) { \
                                symname = (char *)(elf->data + EGET(strtab->sh_offset) + EGET(sym->st_name)); \
                                if (*find_sym == '*') { \
                                        printf("%s(%s) %5lX %15s %s\n", \
                                               ((*found_sym == 0) ? "\n\t" : "\t"), \
                                               elf->base_filename, \
                                               (long)sym->st_size, \
                                               (char *)get_elfstttype(sym->st_info), \
                                               symname); \
                                        *found_sym = 1; \
                                } else if ((strcmp(find_sym, symname) == 0) || \
                                           (strcmp(symname, versioned_symname) == 0)) \
                                        (*found_sym)++; \
                        } \
                        ++sym; \
                } }
                FIND_SYM(32)
                FIND_SYM(64)
        }

        if (be_wewy_wewy_quiet) return NULL;

        if (*find_sym != '*' && *found_sym)
                return find_sym;
        if (be_quiet)
                return NULL;
        else
                return (char *)" - ";
}
/* scan an elf file and show all the fun stuff */
#define prints(str) write(fileno(stdout), str, strlen(str))
static void scanelf_file(const char *filename)
{
        unsigned long i;
        char found_pax, found_phdr, found_relro, found_load, found_textrel, 
             found_rpath, found_needed, found_interp, found_bind,
             found_sym, found_lib, found_file, found_textrels;
        elfobj *elf;
        struct stat st;
        static char *out_buffer = NULL;
        static size_t out_len;

        /* make sure 'filename' exists */
        if (lstat(filename, &st) == -1) {
                if (be_verbose > 2) printf("%s: does not exist\n", filename);
                return;
        }
        /* always handle regular files and handle symlinked files if no -y */
        if (S_ISLNK(st.st_mode)) {
                if (!scan_symlink) return;
                stat(filename, &st);
        }
        if (!S_ISREG(st.st_mode)) {
                if (be_verbose > 2) printf("%s: skipping non-file\n", filename);
                return;
        }

        found_pax = found_phdr = found_relro = found_load = found_textrel = \
        found_rpath = found_needed = found_interp = found_bind = \
        found_sym = found_lib = found_file = found_textrels = 0;

        /* verify this is real ELF */
        if ((elf = readelf(filename)) == NULL) {
                if (be_verbose > 2) printf("%s: not an ELF\n", filename);
                return;
        }

        if (be_verbose > 1)
                printf("%s: scanning file {%s,%s}\n", filename,
                       get_elfeitype(EI_CLASS, elf->elf_class),
                       get_elfeitype(EI_DATA, elf->data[EI_DATA]));
        else if (be_verbose)
                printf("%s: scanning file\n", filename);

        /* init output buffer */
        if (!out_buffer) {
                out_len = sizeof(char) * 80;
                out_buffer = (char*)xmalloc(out_len);
        }
        *out_buffer = '\0';

        /* show the header */
        if (!be_quiet && show_banner) {
                for (i = 0; out_format[i]; ++i) {
                        if (!IS_MODIFIER(out_format[i])) continue;

                        switch (out_format[++i]) {
                        case '%': break;
                        case '#': break;
                        case 'F':
                        case 'p':
                        case 'f': prints("FILE "); found_file = 1; break;
                        case 'o': prints(" TYPE   "); break;
                        case 'x': prints(" PAX   "); break;
                        case 'e': prints("STK/REL/PTL "); break;
                        case 't': prints("TEXTREL "); break;
                        case 'r': prints("RPATH "); break;
                        case 'n': prints("NEEDED "); break;
                        case 'i': prints("INTERP "); break;
                        case 'b': prints("BIND "); break;
                        case 's': prints("SYM "); break;
                        case 'N': prints("LIB "); break;
                        case 'T': prints("TEXTRELS "); break;
                        default: warnf("'%c' has no title ?", out_format[i]);
                        }
                }
                if (!found_file) prints("FILE ");
                prints("\n");
                found_file = 0;
                show_banner = 0;
        }

        /* dump all the good stuff */
        for (i = 0; out_format[i]; ++i) {
                const char *out;
                const char *tmp;

                /* make sure we trim leading spaces in quiet mode */
                if (be_quiet && *out_buffer == ' ' && !out_buffer[1])
                        *out_buffer = '\0';

                if (!IS_MODIFIER(out_format[i])) {
                        xchrcat(&out_buffer, out_format[i], &out_len);
                        continue;
                }

                out = NULL;
                be_wewy_wewy_quiet = (out_format[i] == '#');
                switch (out_format[++i]) {
                case '%':
                case '#':
                        xchrcat(&out_buffer, out_format[i], &out_len); break;
                case 'F':
                        found_file = 1;
                        if (be_wewy_wewy_quiet) break;
                        xstrcat(&out_buffer, filename, &out_len);
                        break;
                case 'p':
                        found_file = 1;
                        if (be_wewy_wewy_quiet) break;
                        tmp = filename;
                        if (search_path) {
                                ssize_t len_search = strlen(search_path);
                                ssize_t len_file = strlen(filename);
                                if (!strncmp(filename, search_path, len_search) && \
                                    len_file > len_search)
                                        tmp += len_search;
                                if (*tmp == '/' && search_path[len_search-1] == '/') tmp++;
                        }
                        xstrcat(&out_buffer, tmp, &out_len);
                        break;
                case 'f':
                        found_file = 1;
                        if (be_wewy_wewy_quiet) break;
                        tmp = strrchr(filename, '/');
                        tmp = (tmp == NULL ? filename : tmp+1);
                        xstrcat(&out_buffer, tmp, &out_len);
                        break;
                case 'o': out = get_elfetype(elf); break;
                case 'x': out = scanelf_file_pax(elf, &found_pax); break;
                case 'e': out = scanelf_file_phdr(elf, &found_phdr, &found_relro, &found_load); break;
                case 't': out = scanelf_file_textrel(elf, &found_textrel); break;
                case 'T': out = scanelf_file_textrels(elf, &found_textrels, &found_textrel); break;
                case 'r': scanelf_file_rpath(elf, &found_rpath, &out_buffer, &out_len); break;
                case 'n':
                case 'N': out = scanelf_file_needed_lib(elf, &found_needed, &found_lib, (out_format[i]=='N'), &out_buffer, &out_len); break;
                case 'i': out = scanelf_file_interp(elf, &found_interp); break;
                case 'b': out = scanelf_file_bind(elf, &found_bind); break;
                case 's': out = scanelf_file_sym(elf, &found_sym); break;
                default: warnf("'%c' has no scan code?", out_format[i]);
                }
                if (out) xstrcat(&out_buffer, out, &out_len);
        }

#define FOUND_SOMETHING() \
        (found_pax || found_phdr || found_relro || found_load || found_textrel || \
         found_rpath || found_needed || found_interp || found_bind || \
         found_sym || found_lib || found_textrels)

        if (!found_file && (!be_quiet || (be_quiet && FOUND_SOMETHING()))) {
                xchrcat(&out_buffer, ' ', &out_len);
                xstrcat(&out_buffer, filename, &out_len);
        }
        if (!be_quiet || (be_quiet && FOUND_SOMETHING())) {
                puts(out_buffer);
                fflush(stdout);
        }

        unreadelf(elf);
}

/* scan a directory for ET_EXEC files and print when we find one */
static void scanelf_dir(const char *path)
{
        register DIR *dir;
        register struct dirent *dentry;
        struct stat st_top, st;
        char buf[_POSIX_PATH_MAX];
        size_t pathlen = 0, len = 0;

        /* make sure path exists */
        if (lstat(path, &st_top) == -1) {
                if (be_verbose > 2) printf("%s: does not exist\n", path);
                return;
        }

        /* ok, if it isn't a directory, assume we can open it */
        if (!S_ISDIR(st_top.st_mode)) {
                scanelf_file(path);
                return;
        }

        /* now scan the dir looking for fun stuff */
        if ((dir = opendir(path)) == NULL) {
                warnf("could not opendir %s: %s", path, strerror(errno));
                return;
        }
        if (be_verbose) printf("%s: scanning dir\n", path);

        pathlen = strlen(path);
        while ((dentry = readdir(dir))) {
                if (!strcmp(dentry->d_name, ".") || !strcmp(dentry->d_name, ".."))
                        continue;
                len = (pathlen + 1 + strlen(dentry->d_name) + 1);
                if (len >= sizeof(buf)) {
                        warnf("Skipping '%s': len > sizeof(buf); %lu > %lu\n", path,
                              (unsigned long)len, (unsigned long)sizeof(buf));
                        continue;
                }
                sprintf(buf, "%s/%s", path, dentry->d_name);
                if (lstat(buf, &st) != -1) {
                        if (S_ISREG(st.st_mode))
                                scanelf_file(buf);
                        else if (dir_recurse && S_ISDIR(st.st_mode)) {
                                if (dir_crossmount || (st_top.st_dev == st.st_dev))
                                        scanelf_dir(buf);
                        }
                }
        }
        closedir(dir);
}

static int scanelf_from_file(char *filename)
{
        FILE *fp = NULL;
        char *p;
        char path[_POSIX_PATH_MAX];

        if (((strcmp(filename, "-")) == 0) && (ttyname(0) == NULL))
                fp = stdin;
        else if ((fp = fopen(filename, "r")) == NULL)
                return 1;

        while ((fgets(path, _POSIX_PATH_MAX, fp)) != NULL) {
                if ((p = strchr(path, '\n')) != NULL)
                        *p = 0;
                search_path = path;
                scanelf_dir(path);
        }
        if (fp != stdin)
                fclose(fp);
        return 0;
}

static void load_ld_so_conf()
{
        FILE *fp = NULL;
        char *p;
        char path[_POSIX_PATH_MAX];
        int i = 0;

        if ((fp = fopen("/etc/ld.so.conf", "r")) == NULL)
                return;

        while ((fgets(path, _POSIX_PATH_MAX, fp)) != NULL) {
                if (*path != '/')
                        continue;

                if ((p = strrchr(path, '\r')) != NULL)
                        *p = 0;
                if ((p = strchr(path, '\n')) != NULL)
                        *p = 0;

                ldpaths[i++] = xstrdup(path);

                if (i + 1 == sizeof(ldpaths) / sizeof(*ldpaths))
                        break;
        }
        ldpaths[i] = NULL;

        fclose(fp);
}

/* scan /etc/ld.so.conf for paths */
static void scanelf_ldpath()
{
        char scan_l, scan_ul, scan_ull;
        int i = 0;

        if (!ldpaths[0])
                err("Unable to load any paths from ld.so.conf");

        scan_l = scan_ul = scan_ull = 0;

        while (ldpaths[i]) {
                if (!scan_l   && !strcmp(ldpaths[i], "/lib")) scan_l = 1;
                if (!scan_ul  && !strcmp(ldpaths[i], "/usr/lib")) scan_ul = 1;
                if (!scan_ull && !strcmp(ldpaths[i], "/usr/local/lib")) scan_ull = 1;
                scanelf_dir(ldpaths[i]);
                ++i;
        }

        if (!scan_l)   scanelf_dir("/lib");
        if (!scan_ul)  scanelf_dir("/usr/lib");
        if (!scan_ull) scanelf_dir("/usr/local/lib");
}

/* scan env PATH for paths */
static void scanelf_envpath()
{
        char *path, *p;

        path = getenv("PATH");
        if (!path)
                err("PATH is not set in your env !");
        path = xstrdup(path);

        while ((p = strrchr(path, ':')) != NULL) {
                scanelf_dir(p + 1);
                *p = 0;
        }

        free(path);
}


/* usage / invocation handling functions */
#define PARSE_FLAGS "plRmyxetrnibs:N:TaqvF:f:o:BhV"
#define a_argument required_argument
static struct option const long_opts[] = {
        {"path",      no_argument, NULL, 'p'},
        {"ldpath",    no_argument, NULL, 'l'},
        {"recursive", no_argument, NULL, 'R'},
        {"mount",     no_argument, NULL, 'm'},
        {"symlink",   no_argument, NULL, 'y'},
        {"pax",       no_argument, NULL, 'x'},
        {"header",    no_argument, NULL, 'e'},
        {"textrel",   no_argument, NULL, 't'},
        {"rpath",     no_argument, NULL, 'r'},
        {"needed",    no_argument, NULL, 'n'},
        {"interp",    no_argument, NULL, 'i'},
        {"bind",      no_argument, NULL, 'b'},
        {"symbol",     a_argument, NULL, 's'},
        {"lib",        a_argument, NULL, 'N'},
        {"textrels",  no_argument, NULL, 'T'},
        {"all",       no_argument, NULL, 'a'},
        {"quiet",     no_argument, NULL, 'q'},
        {"verbose",   no_argument, NULL, 'v'},
        {"format",     a_argument, NULL, 'F'},
        {"from",       a_argument, NULL, 'f'},
        {"file",       a_argument, NULL, 'o'},
        {"nobanner",  no_argument, NULL, 'B'},
        {"help",      no_argument, NULL, 'h'},
        {"version",   no_argument, NULL, 'V'},
        {NULL,        no_argument, NULL, 0x0}
};

static const char *opts_help[] = {
        "Scan all directories in PATH environment",
        "Scan all directories in /etc/ld.so.conf",
        "Scan directories recursively",
        "Don't recursively cross mount points",
        "Don't scan symlinks\n",
        "Print PaX markings",
        "Print GNU_STACK/PT_LOAD markings",
        "Print TEXTREL information",
        "Print RPATH information",
        "Print NEEDED information",
        "Print INTERP information",
        "Print BIND information",
        "Find a specified symbol",
        "Find a specified library",
        "Locate cause of TEXTREL",
        "Print all scanned info (-x -e -t -r -b)\n",
        "Only output 'bad' things",
        "Be verbose (can be specified more than once)",
        "Use specified format for output",
        "Read input stream from a filename",
        "Write output stream to a filename",
        "Don't display the header",
        "Print this help and exit",
        "Print version and exit",
        NULL
};

/* display usage and exit */
static void usage(int status)
{
        unsigned long i;
        printf("* Scan ELF binaries for stuff\n\n"
               "Usage: %s [options] <dir1/file1> [dir2 dirN fileN ...]\n\n", argv0);
        printf("Options: -[%s]\n", PARSE_FLAGS);
        for (i = 0; long_opts[i].name; ++i)
                if (long_opts[i].has_arg == no_argument)
                        printf("  -%c, --%-13s* %s\n", long_opts[i].val, 
                               long_opts[i].name, opts_help[i]);
                else
                        printf("  -%c, --%-6s <arg> * %s\n", long_opts[i].val,
                               long_opts[i].name, opts_help[i]);

        if (status != EXIT_SUCCESS)
                exit(status);

        puts("\nThe format modifiers for the -F option are:");
        puts(" F Filename \tx PaX Flags \te STACK/RELRO");
        puts(" t TEXTREL  \tr RPATH     \tn NEEDED");
        puts(" i INTERP   \tb BIND      \ts symbol");
        puts(" N library  \to Type      \tT TEXTRELs");
        puts(" p filename (with search path removed)");
        puts(" f base filename");
        puts("Prefix each modifier with '%' (verbose) or '#' (silent)");

        exit(status);
}

/* parse command line arguments and preform needed actions */
static void parseargs(int argc, char *argv[])
{
        int i;
        char *from_file = NULL;

        opterr = 0;
        while ((i=getopt_long(argc, argv, PARSE_FLAGS, long_opts, NULL)) != -1) {
                switch (i) {

                case 'V':
                        printf("pax-utils-%s: %s compiled %s\n%s\n"
                               "%s written for Gentoo by <solar and vapier @ gentoo.org>\n",
                               VERSION, __FILE__, __DATE__, rcsid, argv0);
                        exit(EXIT_SUCCESS);
                        break;
                case 'h': usage(EXIT_SUCCESS); break;
                case 'f':
                        if (from_file) err("Don't specify -f twice");
                        from_file = xstrdup(optarg);
                        break;
                case 'o': {
                        FILE *fp = NULL;
                        if ((fp = freopen(optarg, "w", stdout)) == NULL)
                                err("Could not open output stream '%s': %s", optarg, strerror(errno));
                        SET_STDOUT(fp);
                        break;
                }

                case 's': {
                        size_t len;
                        if (find_sym) err("Don't specify -s twice");
                        find_sym = xstrdup(optarg);
                        len = strlen(find_sym) + 1;
                        versioned_symname = (char*)xmalloc(sizeof(char) * (len+1));
                        sprintf(versioned_symname, "%s@", find_sym);
                        break;
                }
                case 'N': {
                        if (find_lib) err("Don't specify -N twice");
                        find_lib = xstrdup(optarg);
                        break;
                }

                case 'F': {
                        if (out_format) err("Don't specify -F twice");
                        out_format = xstrdup(optarg);
                        break;
                }

                case 'y': scan_symlink = 0; break;
                case 'B': show_banner = 0; break;
                case 'l': scan_ldpath = 1; break;
                case 'p': scan_envpath = 1; break;
                case 'R': dir_recurse = 1; break;
                case 'm': dir_crossmount = 0; break;
                case 'x': show_pax = 1; break;
                case 'e': show_phdr = 1; break;
                case 't': show_textrel = 1; break;
                case 'r': show_rpath = 1; break;
                case 'n': show_needed = 1; break;
                case 'i': show_interp = 1; break;
                case 'b': show_bind = 1; break;
                case 'T': show_textrels = 1; break;
                case 'q': be_quiet = 1; break;
                case 'v': be_verbose = (be_verbose % 20) + 1; break;
                case 'a': show_pax = show_phdr = show_textrel = show_rpath = show_bind = 1; break;

                case ':':
                        err("Option missing parameter\n");
                case '?':
                        err("Unknown option\n");
                default:
                        err("Unhandled option '%c'", i);
                }
        }

        /* let the format option override all other options */
        if (out_format) {
                show_pax = show_phdr = show_textrel = show_rpath = \
                show_needed = show_interp = show_bind = show_textrels = 0;
                for (i = 0; out_format[i]; ++i) {
                        if (!IS_MODIFIER(out_format[i])) continue;

                        switch (out_format[++i]) {
                        case '%': break;
                        case '#': break;
                        case 'F': break;
                        case 'p': break;
                        case 'f': break;
                        case 's': break;
                        case 'N': break;
                        case 'o': break;
                        case 'x': show_pax = 1; break;
                        case 'e': show_phdr = 1; break;
                        case 't': show_textrel = 1; break;
                        case 'r': show_rpath = 1; break;
                        case 'n': show_needed = 1; break;
                        case 'i': show_interp = 1; break;
                        case 'b': show_bind = 1; break;
                        case 'T': show_textrels = 1; break;
                        default:
                                err("Invalid format specifier '%c' (byte %i)", 
                                    out_format[i], i+1);
                        }
                }

        /* construct our default format */
        } else {
                size_t fmt_len = 30;
                out_format = (char*)xmalloc(sizeof(char) * fmt_len);
                if (!be_quiet)     xstrcat(&out_format, "%o ", &fmt_len);
                if (show_pax)      xstrcat(&out_format, "%x ", &fmt_len);
                if (show_phdr)     xstrcat(&out_format, "%e ", &fmt_len);
                if (show_textrel)  xstrcat(&out_format, "%t ", &fmt_len);
                if (show_rpath)    xstrcat(&out_format, "%r ", &fmt_len);
                if (show_needed)   xstrcat(&out_format, "%n ", &fmt_len);
                if (show_interp)   xstrcat(&out_format, "%i ", &fmt_len);
                if (show_bind)     xstrcat(&out_format, "%b ", &fmt_len);
                if (show_textrels) xstrcat(&out_format, "%T ", &fmt_len);
                if (find_sym)      xstrcat(&out_format, "%s ", &fmt_len);
                if (find_lib)      xstrcat(&out_format, "%N ", &fmt_len);
                if (!be_quiet)     xstrcat(&out_format, "%F ", &fmt_len);
        }
        if (be_verbose > 2) printf("Format: %s\n", out_format);

        /* now lets actually do the scanning */
        if (scan_ldpath || (show_rpath && be_quiet))
                load_ld_so_conf();
        if (scan_ldpath) scanelf_ldpath();
        if (scan_envpath) scanelf_envpath();
        if (from_file) {
                scanelf_from_file(from_file);
                free(from_file);
                from_file = *argv;
        }
        if (optind == argc && !scan_ldpath && !scan_envpath && !from_file)
                err("Nothing to scan !?");
        while (optind < argc) {
                search_path = argv[optind++];
                scanelf_dir(search_path);
        }

        /* clean up */
        if (find_sym) {
                free(find_sym);
                free(versioned_symname);
        }
        if (find_lib) free(find_lib);
        if (out_format) free(out_format);
        for (i = 0; ldpaths[i]; ++i)
                free(ldpaths[i]);
}


/* utility funcs */
static char *xstrdup(const char *s)
{
        char *ret = strdup(s);
        if (!ret) err("Could not strdup(): %s", strerror(errno));
        return ret;
}

static void *xmalloc(size_t size)
{
        void *ret = malloc(size);
        if (!ret) err("Could not malloc() %li bytes", (unsigned long)size);
        return ret;
}

static void xstrcat(char **dst, const char *src, size_t *curr_len)
{
        size_t new_len;

        new_len = strlen(*dst) + strlen(src);
        if (*curr_len <= new_len) {
                *curr_len = new_len + (*curr_len / 2);
                *dst = realloc(*dst, *curr_len);
                if (!*dst)
                        err("could not realloc %li bytes", (unsigned long)*curr_len);
        }

        strcat(*dst, src);
}

static inline void xchrcat(char **dst, const char append, size_t *curr_len)
{
        static char my_app[2];
        my_app[0] = append;
        my_app[1] = '\0';
        xstrcat(dst, my_app, curr_len);
}


int main(int argc, char *argv[])
{
        if (argc < 2)
                usage(EXIT_FAILURE);
        parseargs(argc, argv);
        fclose(stdout);
#ifdef __BOUNDS_CHECKING_ON
        warn("The calls to add/delete heap should be off by 1 due to the out_buffer not being freed in scanelf_file()");
#endif
        return EXIT_SUCCESS;
}