Initial checkin for ld.so. This is a combination of effort from Manuel Novoa

III and me.  I've been working on stripping out arch dependant stuff and
replacing it with generic stuff whenever possible.
 -Erik

1 files changed, 837 insertions, 0 deletions

diff --git a/ldso/util/ldconfig.c b/ldso/util/ldconfig.c
new file mode 100644
index 000000000..2b3d50c8e
--- /dev/null
+++ b/ldso/util/ldconfig.c
@@ -0,0 +1,837 @@
+/*
+ * ldconfig - update shared library symlinks
+ *
+ * usage: ldconfig [-DvqnNX] [-f conf] [-C cache] [-r root] dir ...
+ *        ldconfig -l [-Dv] lib ...
+ *        ldconfig -p
+ *        -D: debug mode, don't update links
+ *        -v: verbose mode, print things as we go
+ *        -q: quiet mode, don't print warnings
+ *        -n: don't process standard directories
+ *        -N: don't update the library cache
+ *        -X: don't update the library links
+ *        -l: library mode, manually link libraries
+ *        -p: print the current library cache
+ *        -f conf: use conf instead of /etc/ld.so.conf
+ *        -C cache: use cache instead of /etc/ld.so.cache
+ *        -r root: first, do a chroot to the indicated directory
+ *        dir ...: directories to process
+ *        lib ...: libraries to link
+ *
+ * Copyright 1994-2000 David Engel and Mitch D'Souza
+ *
+ * This program may be used for any purpose as long as this
+ * copyright notice is kept.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <ctype.h>
+#include <getopt.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <a.out.h>
+#include <link.h>
+#include <elf.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <errno.h>
+
+#include "../config.h"
+#include "readelf.h"
+
+#ifdef __GNUC__
+void warn(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
+void error(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
+#endif
+
+char *___strtok = NULL;
+
+/* For SunOS */
+#ifndef PATH_MAX
+#include <limits.h>
+#define PATH_MAX _POSIX_PATH_MAX
+#endif
+
+/* For SunOS */
+#ifndef N_MAGIC
+#define N_MAGIC(exec) ((exec).a_magic & 0xffff)
+#endif
+
+#define EXIT_OK    0
+#define EXIT_FATAL 128
+
+char *prog = NULL;
+int debug = 0;			/* debug mode */
+int verbose = 0;		/* verbose mode */
+int libmode = 0;		/* library mode */
+int nocache = 0;		/* don't build cache */
+int nolinks = 0;		/* don't update links */
+
+char *conffile = LDSO_CONF;	/* default conf file */
+char *cachefile = LDSO_CACHE;	/* default cache file */
+void cache_print(void);
+void cache_dolib(const char *dir, const char *so, int libtype);
+void cache_write(void);
+
+void warn(const char *fmt, ...)
+{
+    va_list ap;
+
+    if (verbose < 0)
+        return;
+
+    fflush(stdout);    /* don't mix output and error messages */
+    fprintf(stderr, "%s: warning: ", prog);
+
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+
+    fprintf(stderr, "\n");
+
+    return;
+}
+
+void error(const char *fmt, ...)
+{
+    va_list ap;
+
+    fflush(stdout);    /* don't mix output and error messages */
+    fprintf(stderr, "%s: ", prog);
+
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+
+    fprintf(stderr, "\n");
+
+    exit(EXIT_FATAL);
+}
+
+void *xmalloc(size_t size)
+{
+    void *ptr;
+    if ((ptr = malloc(size)) == NULL)
+	error("out of memory");
+    return ptr;
+}
+
+char *xstrdup(const char *str)
+{
+    char *ptr;
+    if ((ptr = strdup(str)) == NULL)
+	error("out of memory");
+    return ptr;
+}
+
+/* If shared library, return a malloced copy of the soname and set the
+   type, else return NULL.
+
+   expected_type should be either LIB_ANY or one of the following:-
+   LIB_DLL
+   LIB_ELF
+   LIB_ELF_LIBC5
+   LIB_ELF_LIBC6
+
+   If the lib is ELF and we can not deduce the type the type will
+   be set based on expected_type.
+
+   If the expected, actual/deduced types missmatch we display a warning
+   and use the actual/deduced type.
+*/
+char *is_shlib(const char *dir, const char *name, int *type,
+	int *islink, int expected_type)
+{
+    char *good = NULL;
+    char *cp, *cp2;
+    FILE *file;
+    struct exec exec;
+    ElfW(Ehdr) *elf_hdr;
+    struct stat statbuf;
+    char buff[4096];
+
+    /* see if name is of the form libZ.so* */
+    if ((strncmp(name, "lib", 3) == 0 || strncmp(name, "ld-", 3) == 0) && \
+	name[strlen(name)-1] != '~' && (cp = strstr(name, ".so")))
+    {
+	/* find the start of the Vminor part, if any */
+	if (cp[3] == '.' && (cp2 = strchr(cp + 4, '.')))
+	    cp = cp2;
+	else
+	    cp = cp + strlen(cp);
+
+	/* construct the full path name */
+	sprintf(buff, "%s%s%s", dir, (*dir && strcmp(dir, "/")) ?
+		"/" : "", name);
+
+	/* first, make sure it's a regular file */
+	if (lstat(buff, &statbuf))
+	    warn("can't lstat %s (%s), skipping", buff, strerror(errno));
+	else if (!S_ISREG(statbuf.st_mode) && !S_ISLNK(statbuf.st_mode))
+	    warn("%s is not a regular file or symlink, skipping", buff);
+	else
+	{
+	    /* is it a regular file or a symlink */
+	    *islink = S_ISLNK(statbuf.st_mode);
+
+	    /* then try opening it */
+	    if (!(file = fopen(buff, "rb")))
+		warn("can't open %s (%s), skipping", buff, strerror(errno));
+	    else
+	    {
+		/* now make sure it's a shared library */
+		if (fread(&exec, sizeof exec, 1, file) < 1)
+		    warn("can't read header from %s, skipping", buff);
+		else if (N_MAGIC(exec) != ZMAGIC && N_MAGIC(exec) != QMAGIC)
+		{
+		    elf_hdr = (ElfW(Ehdr) *) &exec;
+		    if (elf_hdr->e_ident[0] != 0x7f ||
+			strncmp(&elf_hdr->e_ident[1], "ELF",3) != 0)
+		    {
+		        /* silently ignore linker scripts */
+		        if (strncmp((char *)&exec, "/* GNU ld", 9) != 0)
+			    warn("%s is not a shared library, skipping", buff);
+		    }
+		    else
+		    {
+		        /* always call readsoname to update type */
+			if(expected_type == LIB_DLL){
+			    warn("%s is not an a.out library, its ELF!\n", buff);
+			    expected_type=LIB_ANY;
+			}
+		        *type = LIB_ELF;
+		        good = readsoname(buff, file, expected_type, type, 
+					  elf_hdr->e_ident[EI_CLASS]);
+			if (good == NULL || *islink)
+			{
+			    if (good != NULL)
+			        free(good);
+			    good = xstrdup(name);
+			}
+			else
+			{
+			    /* if the soname does not match the filename,
+			       issue a warning, but only in debug mode. */
+			    int len = strlen(good);
+			    if (debug && (strncmp(good, name, len) != 0 ||
+				(name[len] != '\0' && name[len] != '.')))
+			        warn("%s has inconsistent soname (%s)",
+				     buff, good);
+			}
+		    }
+		}
+		else
+		{
+		    if (*islink)
+		        good = xstrdup(name);
+		    else
+		    {
+		        good = xmalloc(cp - name + 1);
+			strncpy(good, name, cp - name);
+			good[cp - name] = '\0';
+		    }
+		    if(expected_type != LIB_ANY && expected_type != LIB_DLL)
+		    {
+			warn("%s is not an ELF library, its an a.out DLL!", buff);
+			expected_type=LIB_ANY;
+		    }
+		    
+		    *type = LIB_DLL;
+		}
+		fclose(file);
+	    }
+	}
+    }
+
+    return good;
+}
+
+/* update the symlink to new library */
+void link_shlib(const char *dir, const char *file, const char *so)
+{
+    int change = 1;
+    char libname[4096];
+    char linkname[4096];
+    struct stat libstat;
+    struct stat linkstat;
+
+    /* construct the full path names */
+    sprintf(libname, "%s/%s", dir, file);
+    sprintf(linkname, "%s/%s", dir, so);
+
+    /* see if a link already exists */
+    if (!stat(linkname, &linkstat))
+    {
+	/* now see if it's the one we want */
+	if (stat(libname, &libstat))
+	    warn("can't stat %s (%s)", libname, strerror(errno));
+	else if (libstat.st_dev == linkstat.st_dev &&
+	    libstat.st_ino == linkstat.st_ino)
+	    change = 0;
+    }
+
+    /* then update the link, if required */
+    if (change > 0 && !nolinks)
+    {
+	if (!lstat(linkname, &linkstat))
+	{
+	  if (!S_ISLNK(linkstat.st_mode))
+	  {
+	    warn("%s is not a symlink", linkname);
+	    change = -1;
+	  }
+	  else if (remove(linkname))
+	  {
+	    warn("can't unlink %s (%s)", linkname, strerror(errno));
+	    change = -1;
+	  }
+	}
+	if (change > 0)
+	{
+	  if (symlink(file, linkname))
+	  {
+	    warn("can't link %s to %s (%s)", linkname, file, strerror(errno));
+	    change = -1;
+	  }
+	}
+    }
+
+    /* some people like to know what we're doing */
+    if (verbose > 0)
+	printf("\t%s => %s%s\n", so, file,
+	       change < 0 ? " (SKIPPED)" :
+	       (change > 0 ? " (changed)" : ""));
+
+    return;
+}
+
+/* figure out which library is greater */
+int libcmp(char *p1, char *p2)
+{
+    while (*p1)
+    {
+	if (isdigit(*p1) && isdigit(*p2))
+	{
+	    /* must compare this numerically */
+	    int v1, v2;
+	    v1 = strtoul(p1, &p1, 10);
+	    v2 = strtoul(p2, &p2, 10);
+	    if (v1 != v2)
+		return v1 - v2;
+	}
+	else if (isdigit(*p1) && !isdigit(*p2))
+	    return 1;
+	else if (!isdigit(*p1) && isdigit(*p2))
+	    return -1;
+	else if (*p1 != *p2)
+	    return *p1 - *p2;
+	else
+	    p1++, p2++;
+    }
+
+    return *p1 - *p2;
+}
+
+struct lib
+{
+    char *so;			/* soname of a library */
+    char *name;			/* name of a library */
+    int libtype;		/* type of a library */
+    int islink;			/* is it a symlink */
+    struct lib *next;		/* next library in list */
+};
+
+/* update all shared library links in a directory */
+void scan_dir(const char *name)
+{
+    DIR *dir;
+    struct dirent *ent;
+    char *so;
+    struct lib *lp, *libs = NULL;
+    int libtype, islink;
+    int expected_type = LIB_ANY;
+    char *t;
+
+    /* Check for an embedded expected type */
+    t=strrchr(name, '=');
+    if( t )
+    {
+	*t++ = '\0'; /* Skip = char */
+	if(strcasecmp(t, "libc4") == 0)
+	{
+	    expected_type = LIB_DLL;
+	} 
+	else
+	{
+	    if(strcasecmp(t, "libc5") == 0)
+	    {
+		expected_type = LIB_ELF_LIBC5; 
+	    }
+	    else
+	    {
+		if(strcasecmp(t, "libc6") == 0)
+		{
+		    expected_type = LIB_ELF_LIBC6;
+		}
+		else
+		{
+		    warn("Unknown type field '%s' for dir '%s' - ignored\n", t, name);
+		    expected_type = LIB_ANY;
+		}
+	    }
+	}
+    }
+
+    /* let 'em know what's going on */
+    if (verbose > 0)
+	printf("%s:\n", name);
+
+    /* if we can't open it, we can't do anything */
+    if ((dir = opendir(name)) == NULL)
+    {
+	warn("can't open %s (%s), skipping", name, strerror(errno));
+	return;
+    }
+
+    /* yes, we have to look at every single file */
+    while ((ent = readdir(dir)) != NULL)
+    {
+	/* if it's not a shared library, don't bother */
+	if ((so = is_shlib(name, ent->d_name, &libtype, &islink, expected_type)) == NULL)
+	    continue;
+
+	/* have we already seen one with the same so name? */
+	for (lp = libs; lp; lp = lp->next)
+	{
+	    if (strcmp(so, lp->so) == 0)
+	    {
+	        /* we have, which one do we want to use? */
+	        if ((!islink && lp->islink) ||
+		    (islink == lp->islink && 
+		     libcmp(ent->d_name, lp->name) > 0))
+		{
+		    /* let's use the new one */
+		    free(lp->name);
+		    lp->name = xstrdup(ent->d_name);
+		    lp->libtype = libtype;
+		    lp->islink = islink;
+		} 
+		break;
+	    }
+	}
+
+	/* congratulations, you're the first one we've seen */
+	if (!lp)
+	{
+	    lp = xmalloc(sizeof *lp);
+	    lp->so = xstrdup(so);
+	    lp->name = xstrdup(ent->d_name);
+	    lp->libtype = libtype;
+	    lp->islink = islink;
+	    lp->next = libs;
+	    libs = lp;
+	}
+
+	free(so);
+    }
+
+    /* don't need this any more */
+    closedir(dir);
+
+    /* now we have all the latest libs, update the links */
+    for (lp = libs; lp; lp = lp->next)
+    {
+        if (!lp->islink)
+	    link_shlib(name, lp->name, lp->so);
+	if (!nocache)
+	    cache_dolib(name, lp->so, lp->libtype);
+    }
+
+    /* always try to clean up after ourselves */
+    while (libs)
+    {
+	lp = libs->next;
+	free(libs->so);
+	free(libs->name);
+	free(libs);
+	libs = lp;
+    }
+
+    return;
+}
+
+/* return the list of system-specific directories */
+char *get_extpath(void)
+{
+    char *res = NULL, *cp;
+    FILE *file;
+    struct stat stat;
+
+    if ((file = fopen(conffile, "r")) != NULL)
+    {
+	fstat(fileno(file), &stat);
+	res = xmalloc(stat.st_size + 1);
+	fread(res, 1, stat.st_size, file);
+	fclose(file);
+	res[stat.st_size] = '\0';
+
+	/* convert comments fo spaces */
+	for (cp = res; *cp; /*nada*/) {
+	  if (*cp == '#') {
+	    do
+	      *cp++ = ' ';
+	    while (*cp && *cp != '\n');
+	  } else {
+	    cp++;
+	  }
+	}	  
+    }
+
+    return res;
+}
+
+void usage(void)
+{
+    fprintf(stderr,
+	    "ldconfig - update shared library symlinks\n"
+	    "\n"
+	    "usage: ldconfig [-DvqnNX] [-f conf] [-C cache] [-r root] dir ...\n"
+	    "       ldconfig -l [-Dv] lib ...\n"
+	    "       ldconfig -p\n"
+	    "\t-D:\t\tdebug mode, don't update links\n"
+	    "\t-v:\t\tverbose mode, print things as we go\n"
+	    "\t-q:\t\tquiet mode, don't print warnings\n"
+	    "\t-n:\t\tdon't process standard directories\n"
+	    "\t-N:\t\tdon't update the library cache\n"
+	    "\t-X:\t\tdon't update the library links\n"
+	    "\t-l:\t\tlibrary mode, manually link libraries\n"
+	    "\t-p:\t\tprint the current library cache\n"
+	    "\t-f conf :\tuse conf instead of %s\n"
+	    "\t-C cache:\tuse cache instead of %s\n"
+	    "\t-r root :\tfirst, do a chroot to the indicated directory\n"
+	    "\tdir ... :\tdirectories to process\n"
+	    "\tlib ... :\tlibraries to link\n"
+	    "\n"
+	    "Copyright 1994-2000 David Engel and Mitch D'Souza\n",
+	    LDSO_CONF, LDSO_CACHE
+	    );
+    exit(EXIT_FATAL);
+}
+
+int main(int argc, char **argv)
+{
+    int i, c;
+    int nodefault = 0;
+    int printcache = 0;
+    char *cp, *dir, *so;
+    char *extpath;
+    int libtype, islink;
+    char *chroot_dir = NULL;
+
+    prog = argv[0];
+    opterr = 0;
+
+    while ((c = getopt(argc, argv, "DvqnNXlpf:C:r:")) != EOF)
+	switch (c)
+	{
+	case 'D':
+	    debug = 1;		/* debug mode */
+	    nocache = 1;
+	    nolinks = 1;
+	    verbose = 1;
+	    break;
+	case 'v':
+	    verbose = 1;	/* verbose mode */
+	    break;
+	case 'q':
+	    if (verbose <= 0)
+	        verbose = -1;	/* quiet mode */
+	    break;
+	case 'n':
+	    nodefault = 1;	/* no default dirs */
+	    nocache = 1;
+	    break;
+	case 'N':
+	    nocache = 1;	/* don't build cache */
+	    break;
+	case 'X':
+	    nolinks = 1;	/* don't update links */
+	    break;
+	case 'l':
+	    libmode = 1;	/* library mode */
+	    break;
+	case 'p':
+	    printcache = 1;	/* print cache */
+	    break;
+	case 'f':
+	    conffile = optarg;	/* alternate conf file */
+	    break;
+	case 'C':
+	    cachefile = optarg;	/* alternate cache file */
+	    break;
+	case 'r':
+	    chroot_dir = optarg;
+	    break;
+	default:
+	    usage();
+	    break;
+
+	/* THE REST OF THESE ARE UNDOCUMENTED AND MAY BE REMOVED
+	   IN FUTURE VERSIONS. */
+	}
+
+    if (chroot_dir && *chroot_dir) {
+	if (chroot(chroot_dir) < 0)
+	    error("couldn't chroot to %s (%s)", chroot_dir, strerror(errno));
+        if (chdir("/") < 0)
+	    error("couldn't chdir to / (%s)", strerror(errno));
+    }
+
+    /* allow me to introduce myself, hi, my name is ... */
+    if (verbose > 0)
+	printf("%s: version %s\n", argv[0], VERSION);
+
+    if (printcache)
+    {
+	/* print the cache -- don't you trust me? */
+	cache_print();
+	exit(EXIT_OK);
+    }
+    else if (libmode)
+    {
+	/* so you want to do things manually, eh? */
+
+	/* ok, if you're so smart, which libraries do we link? */
+	for (i = optind; i < argc; i++)
+	{
+	    /* split into directory and file parts */
+	    if (!(cp = strrchr(argv[i], '/')))
+	    {
+		dir = ".";	/* no dir, only a filename */
+		cp = argv[i];
+	    }
+	    else
+	    {
+		if (cp == argv[i])
+		    dir = "/";	/* file in root directory */
+		else
+		    dir = argv[i];
+		*cp++ = '\0';	/* neither of the above */
+	    }
+
+	    /* we'd better do a little bit of checking */
+	    if ((so = is_shlib(dir, cp, &libtype, &islink, LIB_ANY)) == NULL)
+		error("%s%s%s is not a shared library", dir,
+		      (*dir && strcmp(dir, "/")) ? "/" : "", cp);
+
+	    /* so far, so good, maybe he knows what he's doing */
+	    link_shlib(dir, cp, so);
+	}
+    }
+    else
+    {
+	/* the lazy bum want's us to do all the work for him */
+
+	/* don't cache dirs on the command line */
+	int nocache_save = nocache;
+	nocache = 1;
+
+	/* OK, which directories should we do? */
+	for (i = optind; i < argc; i++)
+	    scan_dir(argv[i]);
+
+	/* restore the desired caching state */
+	nocache = nocache_save;
+
+	/* look ma, no defaults */
+	if (!nodefault)
+	{
+	    /* I guess the defaults aren't good enough */
+	    if ((extpath = get_extpath()))
+	    {
+		for (cp = strtok(extpath, DIR_SEP); cp;
+		     cp = strtok(NULL, DIR_SEP))
+		    scan_dir(cp);
+		free(extpath);
+	    }
+
+#ifdef UCLIBC_DEVEL
+	    scan_dir(UCLIBC_INSTALL_DIR"/lib");
+#else
+	    /* everybody needs these, don't they? */
+	    scan_dir("/usr/lib");
+	    scan_dir("/lib");
+#endif
+	}
+
+	if (!nocache)
+	    cache_write();
+    }
+
+    exit(EXIT_OK);
+}
+
+typedef struct liblist
+{
+    int flags;
+    int sooffset;
+    int liboffset;
+    char *soname;
+    char *libname;
+    struct liblist *next;
+} liblist_t;
+
+static header_t magic = { LDSO_CACHE_MAGIC, LDSO_CACHE_VER, 0 };
+static liblist_t *lib_head = NULL;
+
+static int liblistcomp(liblist_t *x, liblist_t *y)
+{
+    int res;
+
+    if ((res = libcmp(x->soname, y->soname)) == 0)
+    {
+        res = libcmp(strrchr(x->libname, '/') + 1,
+		     strrchr(y->libname, '/') + 1);
+    }
+
+    return res;
+}
+
+void cache_dolib(const char *dir, const char *so, int libtype)
+{
+    char fullpath[PATH_MAX];
+    liblist_t *new_lib, *cur_lib;
+
+    magic.nlibs++;
+    sprintf(fullpath, "%s/%s", dir, so);
+    new_lib = xmalloc(sizeof (liblist_t));
+    new_lib->flags = libtype;
+    new_lib->soname = xstrdup(so);
+    new_lib->libname = xstrdup(fullpath);
+
+    if (lib_head == NULL || liblistcomp(new_lib, lib_head) > 0)
+    {
+        new_lib->next = lib_head;
+	lib_head = new_lib;
+    }
+    else
+    {
+        for (cur_lib = lib_head; cur_lib->next != NULL &&
+	     liblistcomp(new_lib, cur_lib->next) <= 0;
+	     cur_lib = cur_lib->next)
+	    /* nothing */;
+	new_lib->next = cur_lib->next;
+	cur_lib->next = new_lib;
+    }
+}
+
+void cache_write(void)
+{
+    int cachefd;
+    int stroffset = 0;
+    char tempfile[4096];
+    liblist_t *cur_lib;
+
+    if (!magic.nlibs)
+	return;
+
+    sprintf(tempfile, "%s~", cachefile);
+
+    if (unlink(tempfile) && errno != ENOENT)
+        error("can't unlink %s (%s)", tempfile, strerror(errno));
+
+    if ((cachefd = creat(tempfile, 0644)) < 0)
+	error("can't create %s (%s)", tempfile, strerror(errno));
+
+    if (write(cachefd, &magic, sizeof (header_t)) != sizeof (header_t))
+	error("can't write %s (%s)", tempfile, strerror(errno));
+
+    for (cur_lib = lib_head; cur_lib != NULL; cur_lib = cur_lib->next)
+    {
+        cur_lib->sooffset = stroffset;
+	stroffset += strlen(cur_lib->soname) + 1;
+	cur_lib->liboffset = stroffset;
+	stroffset += strlen(cur_lib->libname) + 1;
+	if (write(cachefd, cur_lib, sizeof (libentry_t)) !=
+	    sizeof (libentry_t))
+	    error("can't write %s (%s)", tempfile, strerror(errno));
+    }
+
+    for (cur_lib = lib_head; cur_lib != NULL; cur_lib = cur_lib->next)
+    {
+      if (write(cachefd, cur_lib->soname, strlen(cur_lib->soname) + 1)
+	  != strlen(cur_lib->soname) + 1)
+	  error("can't write %s (%s)", tempfile, strerror(errno));
+      if (write(cachefd, cur_lib->libname, strlen(cur_lib->libname) + 1)
+	  != strlen(cur_lib->libname) + 1)
+	  error("can't write %s (%s)", tempfile, strerror(errno));
+    }
+
+    if (close(cachefd))
+        error("can't close %s (%s)", tempfile, strerror(errno));
+
+    if (chmod(tempfile, 0644))
+	error("can't chmod %s (%s)", tempfile, strerror(errno));
+
+    if (rename(tempfile, cachefile))
+	error("can't rename %s (%s)", tempfile, strerror(errno));
+}
+
+void cache_print(void)
+{
+    caddr_t c;
+    struct stat st;
+    int fd = 0;
+    char *strs;
+    header_t *header;
+    libentry_t *libent;
+
+    if (stat(cachefile, &st) || (fd = open(cachefile, O_RDONLY))<0)
+	error("can't read %s (%s)", cachefile, strerror(errno));
+    if ((c = mmap(0,st.st_size, PROT_READ, MAP_SHARED ,fd, 0)) == (caddr_t)-1)
+	error("can't map %s (%s)", cachefile, strerror(errno));
+    close(fd);
+
+    if (memcmp(((header_t *)c)->magic, LDSO_CACHE_MAGIC, LDSO_CACHE_MAGIC_LEN))
+	error("%s cache corrupt", cachefile);
+
+    if (memcmp(((header_t *)c)->version, LDSO_CACHE_VER, LDSO_CACHE_VER_LEN))
+	error("wrong cache version - expected %s", LDSO_CACHE_VER);
+
+    header = (header_t *)c;
+    libent = (libentry_t *)(c + sizeof (header_t));
+    strs = (char *)&libent[header->nlibs];
+
+    printf("%d libs found in cache `%s' (version %s)\n",
+	    header->nlibs, cachefile, LDSO_CACHE_VER);
+
+    for (fd = 0; fd < header->nlibs; fd++)
+    {
+	printf("\t%s ", strs + libent[fd].sooffset);
+	switch (libent[fd].flags & ~LIB_ELF64) 
+	{
+	  case LIB_DLL:
+	    printf("(libc4)");
+	    break;
+	  case LIB_ELF:
+	    printf("(ELF%s)", libent[fd].flags & LIB_ELF64 ? "/64" : "");
+	    break;
+	  case LIB_ELF_LIBC5:
+	  case LIB_ELF_LIBC6:
+	    printf("(libc%d%s)", (libent[fd].flags & ~LIB_ELF64) + 3,
+		   libent[fd].flags & LIB_ELF64 ? "/64" : "");
+	    break;
+	  default:
+	    printf("(unknown)");
+	    break;
+	}
+	printf(" => %s\n", strs + libent[fd].liboffset);
+    }
+
+    munmap (c,st.st_size);
+}
+