gentoo-projects/pax-utils/scanelf.c

/*
 * Copyright 2003 Ned Ludd <solar@gentoo.org>
 * Copyright 1999-2005 Gentoo Foundation
 * Distributed under the terms of the GNU General Public License v2
 * $Header: /var/cvsroot/gentoo-projects/pax-utils/scanelf.c,v 1.40 2005/04/21 00:13:03 solar 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>
#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 1.40 2005/04/21 00:13:03 solar Exp $";
#define argv0 "scanelf"


/* 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(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);
static int xemptybuffer(const char *buff);

/* variables to control behavior */
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_stack = 0;
static char show_textrel = 0;
static char show_rpath = 0;
static char show_needed = 0;
static char show_interp = 0;
static char show_banner = 1;
static char be_quiet = 0;
static char be_verbose = 0;
static char *find_sym = NULL, *versioned_symname = NULL;
static char *out_format = NULL;


/* sub-funcs for scanelf_file() */
static char *scanelf_file_pax(elfobj *elf, char *found_pax)
{
        static char *paxflags;

        if (!show_pax) return NULL;

        paxflags = pax_short_hf_flags(PAX_FLAGS(elf));
        if (!be_quiet || (be_quiet && strncmp(paxflags, "PeMRxS", 6))) {
                *found_pax = 1;
                return paxflags;
        }

        return NULL;
}
static char *scanelf_file_stack(elfobj *elf, char *found_stack, char *found_relro)
{
        static char ret[7];
        char *found;
        int i, off, shown;

        if (!show_stack) return NULL;

        shown = 0;
        sprintf(ret, "--- ---");
#define SHOW_STACK(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_GNU_STACK) { \
                        found = found_stack; \
                        off = 0; \
                } else if (EGET(phdr[i].p_type) == PT_GNU_RELRO) { \
                        found = found_relro; \
                        off = 3; \
                } else \
                        continue; \
                if (be_quiet && !(EGET(phdr[i].p_flags) & PF_X)) \
                        continue; \
                memcpy(ret+off, gnu_short_stack_flags(EGET(phdr[i].p_flags)), 3); \
                *found = 1; \
                ++shown; \
        } \
        }
        SHOW_STACK(32)
        SHOW_STACK(64)
        if (be_quiet && !shown)
                return NULL;
        else
                return ret;
}
static char *scanelf_file_textrel(elfobj *elf, char *found_textrel)
{
        static char *ret = "TEXTREL";
        int i;

        if (!show_textrel) return NULL;

#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); \
        for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                if (phdr[i].p_type != PT_DYNAMIC) continue; \
                dyn = DYN ## B (elf->data + EGET(phdr[i].p_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 ret; \
                        } \
                        ++dyn; \
                } \
        } }
        SHOW_TEXTREL(32)
        SHOW_TEXTREL(64)
        if (be_quiet)
                return NULL;
        else
                return "   -   ";
}
static void scanelf_file_rpath(elfobj *elf, char *found_rpath, char **ret, size_t *ret_len)
{
        /* TODO: if be_quiet, only output RPATH's which aren't in /etc/ld.so.conf */
        int i;
        char *rpath, *runpath;
        void *strtbl_void;

        if (!show_rpath) return;

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

        if (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); \
                for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                        if (EGET(phdr[i].p_type) != PT_DYNAMIC) continue; \
                        dyn = DYN ## B (elf->data + EGET(phdr[i].p_offset)); \
                        while (EGET(dyn->d_tag) != DT_NULL) { \
                                if (EGET(dyn->d_tag) == DT_RPATH) { \
                                        if (rpath) warn("ELF has multiple DT_RPATH's !?"); \
                                        rpath = elf->data + EGET(strtbl->sh_offset) + EGET(dyn->d_un.d_ptr); \
                                        *found_rpath = 1; \
                                } else if (EGET(dyn->d_tag) == DT_RUNPATH) { \
                                        if (runpath) warn("ELF has multiple DT_RUNPATH's !?"); \
                                        runpath = elf->data + EGET(strtbl->sh_offset) + EGET(dyn->d_un.d_ptr); \
                                        *found_rpath = 1; \
                                } \
                                ++dyn; \
                        } \
                } }
                SHOW_RPATH(32)
                SHOW_RPATH(64)
        }

        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 void scanelf_file_needed(elfobj *elf, char *found_needed, char **ret, size_t *ret_len)
{
        int i;
        char *needed;
        void *strtbl_void;

        if (!show_needed) return;

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

        if (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); \
                for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
                        if (EGET(phdr[i].p_type) != PT_DYNAMIC) continue; \
                        dyn = DYN ## B (elf->data + EGET(phdr[i].p_offset)); \
                        while (EGET(dyn->d_tag) != DT_NULL) { \
                                if (EGET(dyn->d_tag) == DT_NEEDED) { \
                                        needed = elf->data + EGET(strtbl->sh_offset) + EGET(dyn->d_un.d_ptr); \
                                        if (*found_needed) xchrcat(ret, ',', ret_len); \
                                        xstrcat(ret, needed, ret_len); \
                                        *found_needed = 1; \
                                } \
                                ++dyn; \
                        } \
                } }
                SHOW_NEEDED(32)
                SHOW_NEEDED(64)
        }
}
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 elf->data + EGET(strtbl->sh_offset); \
                }
                SHOW_INTERP(32)
                SHOW_INTERP(64)
        }
        return NULL;
}
static char *scanelf_file_sym(elfobj *elf, char *found_sym, const char *filename)
{
        int i;
        void *symtab_void, *strtab_void;

        if (!find_sym) return NULL;

        symtab_void = elf_findsecbyname(elf, ".symtab");
        strtab_void = elf_findsecbyname(elf, ".strtab");

        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)); \
                int 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"), \
                                               (char *)basename(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 (*find_sym != '*' && *found_sym)
                return find_sym;
        if (be_quiet)
                return NULL;
        else
                return " - ";
}
/* scan an elf file and show all the fun stuff */
#define prints(str) fputs(str, stdout)
static void scanelf_file(const char *filename)
{
        int i;
        char found_pax, found_stack, found_relro, found_textrel, 
             found_rpath, found_needed, found_interp, found_sym,
             found_file;
        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_ISREG(st.st_mode) || (S_ISLNK(st.st_mode) && scan_symlink))) {
                if (be_verbose > 2) printf("%s: skipping non-file\n", filename);
                return;
        }

        found_pax = found_stack = found_relro = found_textrel = \
        found_rpath = found_needed = found_interp = found_sym = \
        found_file = 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(elf, EI_CLASS, elf->elf_class),
                       get_elfeitype(elf, 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 (out_format[i] != '%') continue;

                        switch (out_format[++i]) {
                        case '%': break;
                        case 'F': prints("FILE "); break;
                        case 'o': prints(" TYPE   "); break;
                        case 'x': prints(" PAX   "); break;
                        case 'e': prints("STK/REL "); break;
                        case 't': prints("TEXTREL "); break;
                        case 'r': prints("RPATH "); break;
                        case 'n': prints("NEEDED "); break;
                        case 'i': prints("INTERP "); break;
                        case 's': prints("SYM "); break;
                        }
                }
                prints("\n");
                show_banner = 0;
        }

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

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

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

                out = NULL;
                switch (out_format[++i]) {
                case '%': xchrcat(&out_buffer, '%', &out_len); break;
                case 'F': found_file = 1; xstrcat(&out_buffer, filename, &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_stack(elf, &found_stack, &found_relro); break;
                case 't': out = scanelf_file_textrel(elf, &found_textrel); break;
                case 'r': scanelf_file_rpath(elf, &found_rpath, &out_buffer, &out_len); break;
                case 'n': scanelf_file_needed(elf, &found_needed, &out_buffer, &out_len); break;
                case 'i': out = scanelf_file_interp(elf, &found_interp); break;
                case 's': out = scanelf_file_sym(elf, &found_sym, filename); break;
                }
                if (out) xstrcat(&out_buffer, out, &out_len);
        }

        if (!found_file) {
                if (!be_quiet || found_pax || found_stack || found_textrel || \
                    found_rpath || found_needed || found_interp || found_sym)
                        xstrcat(&out_buffer, filename, &out_len);
        }
        if (!(be_quiet && xemptybuffer(out_buffer)))
                puts(out_buffer);

        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); %d > %d\n", path, (int)len, (int)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);
}

/* scan /etc/ld.so.conf for paths */
static void scanelf_ldpath()
{
        char scan_l, scan_ul, scan_ull;
        char *path, *p;
        FILE *fp;

        if ((fp = fopen("/etc/ld.so.conf", "r")) == NULL)
                err("Unable to open ld.so.conf: %s", strerror(errno));

        scan_l = scan_ul = scan_ull = 0;

        path = (char*)xmalloc(_POSIX_PATH_MAX);
        while ((fgets(path, _POSIX_PATH_MAX, fp)) != NULL)
                if (*path == '/') {
                        if ((p = strrchr(path, '\r')) != NULL)
                                *p = 0;
                        if ((p = strrchr(path, '\n')) != NULL)
                                *p = 0;
                        if (!scan_l   && !strcmp(path, "/lib")) scan_l = 1;
                        if (!scan_ul  && !strcmp(path, "/usr/lib")) scan_ul = 1;
                        if (!scan_ull && !strcmp(path, "/usr/local/lib")) scan_ull = 1;
                        scanelf_dir(path);
                }
        free(path);
        fclose(fp);

        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 "plRmyxetrnis:aqvF: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'},
        {"symbol",    a_argument,  NULL, 's'},
        {"all",       no_argument, NULL, 'a'},
        {"quiet",     no_argument, NULL, 'q'},
        {"verbose",   no_argument, NULL, 'v'},
        {"format",    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 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 markings",
        "Print TEXTREL information",
        "Print RPATH information",
        "Print NEEDED information",
        "Print INTERP information",
        "Find a specified symbol",
        "Print all scanned info (-x -e -t -r)\n",
        "Only output 'bad' things",
        "Be verbose (can be specified more than once)",
        "Use specified format for output",
        "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)
{
        int 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]);
        exit(status);
}

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

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

                case 'V':
                        printf("%s compiled %s\n%s\n"
                               "%s written for Gentoo Linux by <solar and vapier @ gentoo.org>\n",
                               __FILE__, __DATE__, rcsid, argv0);
                        exit(EXIT_SUCCESS);
                        break;
                case 'h': usage(EXIT_SUCCESS); break;

                case 'o': {
                        FILE *fp = NULL;
                        fp = freopen(optarg, "w", stdout);
                        if (fp == NULL)
                                err("Could not open output stream '%s': %s", optarg, strerror(errno));
                        stdout = fp;
                        break;
                }

                case 's': {
                        size_t len;
                        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 'F': {
                        out_format = strdup(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_stack = 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 'q': be_quiet = 1; break;
                case 'v': be_verbose = (be_verbose % 20) + 1; break;
                case 'a': show_pax = show_stack = show_textrel = show_rpath = show_needed = show_interp = 1; break;

                case ':':
                        warn("Option missing parameter\n");
                        usage(EXIT_FAILURE);
                        break;
                case '?':
                        warn("Unknown option\n");
                        usage(EXIT_FAILURE);
                        break;
                default:
                        err("Unhandled option '%c'", flag);
                        break;
                }
        }

        if (be_quiet && be_verbose)
                err("You can be quiet or you can be verbose, not both, stupid");

        /* let the format option override all other options */
        if (out_format) {
                show_pax = show_stack = show_textrel = show_rpath = show_needed = show_interp = 0;
                for (flag=0; out_format[flag]; ++flag) {
                        if (out_format[flag] != '%') continue;

                        switch (out_format[++flag]) {
                        case '%': break;
                        case 'F': break;
                        case 's': break;
                        case 'o': break;
                        case 'x': show_pax = 1; break;
                        case 'e': show_stack = 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;
                        default:
                                err("Invalid format specifier '%c' (byte %i)", 
                                    out_format[flag], flag+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_stack)   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 (find_sym)     xstrcat(&out_format, "%s ", &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) scanelf_ldpath();
        if (scan_envpath) scanelf_envpath();
        if (optind == argc && !scan_ldpath && !scan_envpath)
                err("Nothing to scan !?");
        while (optind < argc)
                scanelf_dir(argv[optind++]);

        /* clean up */
        if (find_sym) {
                free(find_sym);
                free(versioned_symname);
        }
        if (out_format) free(out_format);
}


/* utility funcs */
static char *xstrdup(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)
{
        long 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);
}
static int xemptybuffer(const char *buff)
{
        long i;
        for (i=0; buff[i]; ++i)
                if (buff[i] != ' ')
                        return 0;
        return 1;
}


int main(int argc, char *argv[])
{
        if (argc < 2)
                usage(EXIT_FAILURE);
        parseargs(argc, argv);
        fclose(stdout);
        return EXIT_SUCCESS;
}