uclibc-ng/utils/ldconfig.c

/*
 * 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.
 *
 * 2005/09/16: Dan Howell (modified for cross-development)
 */

#include "porting.h"

#define BUFFER_SIZE 4096

struct exec {
	unsigned long a_info;	/* Use macros N_MAGIC, etc for access */
	unsigned a_text;	/* length of text, in bytes */
	unsigned a_data;	/* length of data, in bytes */
	unsigned a_bss;		/* length of uninitialized data area for file, in bytes */
	unsigned a_syms;	/* length of symbol table data in file, in bytes */
	unsigned a_entry;	/* start address */
	unsigned a_trsize;	/* length of relocation info for text, in bytes */
	unsigned a_drsize;	/* length of relocation info for data, in bytes */
};

#if !defined (N_MAGIC)
#define N_MAGIC(exec) ((exec).a_info & 0xffff)
#endif
#define N_MAGIC_SWAP(exec) (bswap_32((exec).a_info) & 0xffff)
/* Code indicating object file or impure executable.  */
#define OMAGIC 0407
/* Code indicating pure executable.  */
#define NMAGIC 0410
/* Code indicating demand-paged executable.  */
#define ZMAGIC 0413
/* This indicates a demand-paged executable with the header in the text.
   The first page is unmapped to help trap NULL pointer references */
#define QMAGIC 0314
/* Code indicating core file.  */
#define CMAGIC 0421

char *___strtok = NULL;

char *prog = NULL;
int debug = 0;			/* debug mode */
int verbose = 0;		/* verbose mode */
int libmode = 0;		/* library mode */
int nolinks = 0;		/* don't update links */
int nocache = 0;		/* don't build cache */
void cache_print(void);
void cache_write(void);
void cache_dolib(const char *dir, const char *so, int libtype);
#ifdef __LDSO_CACHE_SUPPORT__
char *conffile = LDSO_CONF;	/* default conf file */
char *cachefile = LDSO_CACHE;	/* default cache file */
#endif
char *chroot_dir = NULL;
int byteswap = 0;

struct needed_tab {
	char *soname;
	int type;
};

struct needed_tab needed_tab[] = {
	{"libc.so.0", LIB_ELF_LIBC0},
	{"libm.so.0", LIB_ELF_LIBC0},
	{"libdl.so.0", LIB_ELF_LIBC0},
	{"libc.so.5", LIB_ELF_LIBC5},
	{"libm.so.5", LIB_ELF_LIBC5},
	{"libdl.so.1", LIB_ELF_LIBC5},
	{"libc.so.6", LIB_ELF_LIBC6},
	{"libm.so.6", LIB_ELF_LIBC6},
	{"libdl.so.2", LIB_ELF_LIBC6},
	{NULL, LIB_ELF}
};

extern char *chroot_realpath(const char *chroot, const char *path,
			     char resolved_path[]);

/* These two are used internally -- you shouldn't need to use them */
static void verror_msg(const char *s, va_list p)
{
	fflush(stdout);
	fprintf(stderr, "%s: ", prog);
	vfprintf(stderr, s, p);
}

static void warnx(const char *s, ...)
{
	va_list p;

	va_start(p, s);
	verror_msg(s, p);
	va_end(p);
	fprintf(stderr, "\n");
}

static void attribute_noreturn err(int errnum, const char *s, ...)
{
	va_list p;

	va_start(p, s);
	verror_msg(s, p);
	va_end(p);
	fprintf(stderr, "\n");
	exit(errnum);
}

static void vperror_msg(const char *s, va_list p)
{
	int e = errno;

	if (s == 0)
		s = "";
	verror_msg(s, p);
	if (*s)
		s = ": ";
	fprintf(stderr, "%s%s\n", s, strerror(e));
}

static void warn(const char *s, ...)
{
	va_list p;

	va_start(p, s);
	vperror_msg(s, p);
	va_end(p);
}

static void *xmalloc(size_t size)
{
	void *ptr;
	if ((ptr = malloc(size)) == NULL)
		err(EXIT_FAILURE, "out of memory");
	return ptr;
}

static char *xstrdup(const char *str)
{
	char *ptr;
	if ((ptr = strdup(str)) == NULL)
		err(EXIT_FAILURE, "out of memory");
	return ptr;
}

#undef __ELF_NATIVE_CLASS
#undef readsonameXX
#define readsonameXX readsoname32
#define __ELF_NATIVE_CLASS 32
#include "readsoname2.c"

#undef __ELF_NATIVE_CLASS
#undef readsonameXX
#define readsonameXX readsoname64
#define __ELF_NATIVE_CLASS 64
#include "readsoname2.c"
static char *readsoname(char *name, FILE *infile, int expected_type,
			int *type, int elfclass)
{
	char *res;

	if (elfclass == ELFCLASS32)
		res = readsoname32(name, infile, expected_type, type);
	else {
		res = readsoname64(name, infile, expected_type, type);
#if 0
		/* relies on multilib support which we dont have ... */
		*type |= LIB_ELF64;
#endif
	}

	return res;
}

/* 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.
 */
static 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[BUFFER_SIZE];
	char real[BUFFER_SIZE];
	static int byteswapflag = -1;	/* start with byte-order unknown */

	/* see if name is of the form *.so* */
	if (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);

		/* get real path in case of chroot */
		if (!chroot_realpath(chroot_dir, buff, real))
			warn("can't resolve %s in chroot %s", buff, chroot_dir);

		/* first, make sure it's a regular file */
		if (lstat(real, &statbuf))
			warn("skipping %s", buff);
		else if (!S_ISREG(statbuf.st_mode) && !S_ISLNK(statbuf.st_mode))
			warnx("%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(real, "rb")))
				warn("skipping %s", buff);
			else {
				/* now make sure it's a shared library */
				if (fread(&exec, sizeof exec, 1, file) < 1)
					warnx("can't read header from %s, skipping", buff);
				else if (N_MAGIC(exec) != ZMAGIC
				 && N_MAGIC(exec) != QMAGIC
				 && N_MAGIC_SWAP(exec) != ZMAGIC
				 && N_MAGIC_SWAP(exec) != QMAGIC) {
					elf_hdr = (ElfW(Ehdr) *) & exec;
					if (elf_hdr->e_ident[0] != 0x7f ||
					    strncmp((char *)elf_hdr->e_ident + 1, "ELF", 3) != 0)
					{
						/* silently ignore linker scripts */
						if (strncmp((char *)&exec, "/* GNU ld", 9) != 0)
							warnx("%s is not a shared library, skipping", buff);
					} else {
						/* always call readsoname to update type */
						if (expected_type == LIB_DLL) {
							warnx("%s is not an a.out library, it's ELF!", buff);
							expected_type = LIB_ANY;
						}
						*type = LIB_ELF;
						good = readsoname(buff, file, expected_type, type,
						                  elf_hdr->e_ident[EI_CLASS]);
						if (byteswapflag == -1)
							/* byte-order detected */
							byteswapflag = byteswap;
						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] != '.')))
								warnx("%s has inconsistent soname (%s)", buff, good);
						}
					}
				} else {
					/* Determine byte-order */
					byteswap = (N_MAGIC(exec) == ZMAGIC || N_MAGIC(exec) == QMAGIC) ? 0 : 1;
					if (byteswapflag == -1)
						/* byte-order detected */
						byteswapflag = byteswap;

					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) {
						warnx("%s is not an ELF library, its an a.out DLL!", buff);
						expected_type = LIB_ANY;
					}

					*type = LIB_DLL;
				}
				fclose(file);

				if (byteswapflag >= 0 && byteswap != byteswapflag) {
					byteswapflag = -2;
					warnx("mixed byte-order detected, using host byte-order...");
				}
				if (byteswapflag == -2)
					byteswap = 0;
			}
		}
	}

	return good;
}

/* update the symlink to new library */
static void link_shlib(const char *dir, const char *file, const char *so)
{
	int change = 1;
	char libname[BUFFER_SIZE];
	char linkname[BUFFER_SIZE];
	char reallibname[BUFFER_SIZE];
	char reallinkname[BUFFER_SIZE];
	struct stat libstat;
	struct stat linkstat;

	/* construct the full path names */
	sprintf(libname, "%s/%s", dir, file);
	sprintf(linkname, "%s/%s", dir, so);
	if (!chroot_realpath(chroot_dir, libname, reallibname))
		warn("can't resolve %s in chroot %s", libname, chroot_dir);
	if (!chroot_realpath(chroot_dir, linkname, reallinkname))
		warn("can't resolve %s in chroot %s", linkname, chroot_dir);

	/* see if a link already exists */
	if (!stat(reallinkname, &linkstat)) {
		/* now see if it's the one we want */
		if (stat(reallibname, &libstat))
			warn("can't stat %s", libname);
		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(reallinkname, &linkstat)) {
			if (!S_ISLNK(linkstat.st_mode)) {
				warnx("%s is not a symlink", linkname);
				change = -1;
			} else if (remove(reallinkname)) {
				warn("can't unlink %s", linkname);
				change = -1;
			}
		}
		if (change > 0) {
			if (symlink(file, reallinkname)) {
				warn("can't link %s to %s", linkname, file);
				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 */
static 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 */
static void scan_dir(const char *rawname)
{
	DIR *dir;
	const char *name;
	struct dirent *ent;
	char *so, *path, *path_n;
	struct lib *lp, *libs = NULL;
	int i, libtype, islink, expected_type = LIB_ANY;
	char realname[BUFFER_SIZE];

	/* We need a writable copy of this string */
	path = strdup(rawname);
	if (!path) {
		err(EXIT_FAILURE, "Out of memory!\n");
	}
	/* Eliminate all double //s */
	path_n = path;
	while ((path_n = strstr(path_n, "//"))) {
		i = strlen(path_n);
		memmove(path_n, path_n + 1, i - 1);
		*(path_n + i - 1) = '\0';
	}
	name = path;

#if 0
	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 {
					if (strcasecmp(t, "libc0") == 0) {
						expected_type = LIB_ELF_LIBC0;
					} else {
						warnx("Unknown type field '%s' for dir '%s' - ignored", t, name);
						expected_type = LIB_ANY;
					}
				}
			}
		}
	}
#endif

	/* let 'em know what's going on */
	if (verbose > 0)
		printf("%s:\n", name);

	/* get real path in case of chroot */
	if (!chroot_realpath(chroot_dir, name, realname))
		warn("can't resolve %s in chroot %s", name, chroot_dir);

	/* if we can't open it, we can't do anything */
	if ((dir = opendir(realname)) == NULL) {
		warn("skipping %s", name);
		free(path);
		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;
	}

	free(path);
	return;
}

#ifndef __LDSO_CACHE_SUPPORT__
void cache_print(void)
{
	printf("Library cache disabled\n");
}
void cache_dolib(const char *dir, const char *so, int libtype)
{
	return;
}
void cache_write(void)
{
	return;
}
#else
/* return the list of system-specific directories */
static char *get_extpath(void)
{
	char *res = NULL, *cp;
	FILE *file;
	struct stat st;
	char realconffile[BUFFER_SIZE];

	if (!chroot_realpath(chroot_dir, conffile, realconffile))
		return NULL;

	if ((file = fopen(realconffile, "r")) != NULL) {
		fstat(fileno(file), &st);
		res = xmalloc(st.st_size + 1);
		fread(res, 1, st.st_size, file);
		fclose(file);
		res[st.st_size] = '\0';

		/* convert comments fo spaces */
		for (cp = res; *cp; /*nada */ ) {
			if (*cp == '#') {
				do
					*cp++ = ' ';
				while (*cp && *cp != '\n');
			} else {
				cp++;
			}
		}
	}

	return res;
}

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 realcachefile[BUFFER_SIZE];
	char tempfile[BUFFER_SIZE];
	header_t swap_magic;
	header_t *magic_ptr;
	libentry_t swap_lib;
	libentry_t *lib_ptr;
	liblist_t *cur_lib;

	if (!magic.nlibs)
		return;

	if (!chroot_realpath(chroot_dir, cachefile, realcachefile))
		err(EXIT_FAILURE, "can't resolve %s in chroot %s (%s)",
		    cachefile, chroot_dir, strerror(errno));

	sprintf(tempfile, "%s~", realcachefile);

	if (unlink(tempfile) && errno != ENOENT)
		err(EXIT_FAILURE, "can't unlink %s~ (%s)", cachefile,
		    strerror(errno));

	if ((cachefd = creat(tempfile, 0644)) < 0)
		err(EXIT_FAILURE, "can't create %s~ (%s)", cachefile,
		    strerror(errno));

	if (byteswap) {
		swap_magic = magic;
		swap_magic.nlibs = bswap_32(swap_magic.nlibs);
		magic_ptr = &swap_magic;
	} else {
		magic_ptr = &magic;
	}
	if (write(cachefd, magic_ptr, sizeof(header_t)) != sizeof(header_t))
		err(EXIT_FAILURE, "can't write %s~ (%s)", cachefile,
		    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 (byteswap) {
			swap_lib.flags = bswap_32(cur_lib->flags);
			swap_lib.sooffset = bswap_32(cur_lib->sooffset);
			swap_lib.liboffset = bswap_32(cur_lib->liboffset);
			lib_ptr = &swap_lib;
		} else {
			lib_ptr = (libentry_t *) cur_lib;
		}
		if (write(cachefd, lib_ptr, sizeof(libentry_t)) !=
		    sizeof(libentry_t))
			err(EXIT_FAILURE, "can't write %s~ (%s)", cachefile,
			    strerror(errno));
	}

	for (cur_lib = lib_head; cur_lib != NULL; cur_lib = cur_lib->next) {
		if ((size_t)write(cachefd, cur_lib->soname, strlen(cur_lib->soname) + 1)
		    != strlen(cur_lib->soname) + 1)
			err(EXIT_FAILURE, "can't write %s~ (%s)", cachefile,
			    strerror(errno));
		if ((size_t)write(cachefd, cur_lib->libname, strlen(cur_lib->libname) + 1)
		    != strlen(cur_lib->libname) + 1)
			err(EXIT_FAILURE, "can't write %s~ (%s)", cachefile,
			    strerror(errno));
	}

	if (close(cachefd))
		err(EXIT_FAILURE, "can't close %s~ (%s)", cachefile,
		    strerror(errno));

	if (chmod(tempfile, 0644))
		err(EXIT_FAILURE, "can't chmod %s~ (%s)", cachefile,
		    strerror(errno));

	if (rename(tempfile, realcachefile))
		err(EXIT_FAILURE, "can't rename %s~ (%s)", cachefile,
		    strerror(errno));
}

void cache_print(void)
{
	caddr_t c;
	struct stat st;
	int fd = 0;
	char *strs;
	header_t *header;
	libentry_t *libent;
	char realcachefile[BUFFER_SIZE];

	if (!chroot_realpath(chroot_dir, cachefile, realcachefile))
		err(EXIT_FAILURE, "can't resolve %s in chroot %s (%s)",
		    cachefile, chroot_dir, strerror(errno));

	if (stat(realcachefile, &st) || (fd = open(realcachefile, O_RDONLY)) < 0)
		err(EXIT_FAILURE, "can't read %s (%s)", cachefile, strerror(errno));

	c = mmap(0, st.st_size, PROT_READ, LDSO_CACHE_MMAP_FLAGS, fd, 0);
	if (c == MAP_FAILED)
		err(EXIT_FAILURE, "can't map %s (%s)", cachefile, strerror(errno));
	close(fd);

	if (memcmp(((header_t *) c)->magic, LDSO_CACHE_MAGIC, LDSO_CACHE_MAGIC_LEN))
		err(EXIT_FAILURE, "%s cache corrupt", cachefile);

	if (memcmp(((header_t *) c)->version, LDSO_CACHE_VER, LDSO_CACHE_VER_LEN))
		err(EXIT_FAILURE, "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_LIBC0:
			printf("(libc0%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);
}
#endif

static void attribute_noreturn usage(void)
{
	fprintf(stderr,
#ifdef __LDSO_CACHE_SUPPORT__
		"ldconfig - updates symlinks and cache for shared libraries\n\n"
		"Usage: ldconfig [-DvqnNX] [-f conf] [-C cache] [-r root] dir ...\n"
		"       ldconfig -l [-Dv] lib ...\n"
		"       ldconfig -p\n\nOptions:\n"
#else
		"ldconfig - updates symlinks for shared libraries\n\n"
		"Usage: ldconfig [-DvqnX] [-r root] dir ...\n"
		"       ldconfig -l [-Dv] lib ...\n\nOptions:\n"
#endif
		"\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"
#ifdef __LDSO_CACHE_SUPPORT__
		"\t-f conf :\tuse conf instead of %s\n"
		"\t-C cache:\tuse cache instead of %s\n"
#endif
		"\t-r root :\tfirst, do a chroot to the indicated directory\n"
		"\tdir ... :\tdirectories to process\n"
#ifdef __LDSO_CACHE_SUPPORT__
		"\tlib ... :\tlibraries to link\n\n", LDSO_CONF, LDSO_CACHE
#else
		"\tlib ... :\tlibraries to link\n\n"
#endif
	    );
	exit(EXIT_FAILURE);
}

#define DIR_SEP      ":, \t\n"
int main(int argc, char **argv)
{
	int i, c;
	int nodefault = 0;
	char *cp, *dir, *so;
	int libtype, islink;
	int printcache = 0;
#ifdef __LDSO_CACHE_SUPPORT__
	char *extpath;
#endif

	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':
#ifdef __LDSO_CACHE_SUPPORT__
			conffile = optarg;	/* alternate conf file */
#endif
			break;
		case 'C':
#ifdef __LDSO_CACHE_SUPPORT__
			cachefile = optarg;	/* alternate cache file */
#endif
			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) {
			if (chdir(chroot_dir) < 0)
				err(EXIT_FAILURE, "couldn't chroot to %s (%s)", chroot_dir, strerror(errno));
			chroot_dir = ".";
		} else {
			if (chdir("/") < 0)
				err(EXIT_FAILURE, "couldn't chdir to / (%s)", strerror(errno));
			chroot_dir = NULL;
		}
	}

	/* allow me to introduce myself, hi, my name is ... */
	if (verbose > 0)
		printf("%s: uClibc version\n", argv[0]);

	if (printcache) {
		/* print the cache -- don't you trust me? */
		cache_print();
		exit(EXIT_SUCCESS);
	} 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)
				err(EXIT_FAILURE, "%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) {
			scan_dir(UCLIBC_RUNTIME_PREFIX "lib");
			scan_dir(UCLIBC_RUNTIME_PREFIX "usr/lib");
#ifndef __LDSO_CACHE_SUPPORT__
			scan_dir(UCLIBC_RUNTIME_PREFIX "usr/X11R6/lib");
#else
			/* I guess the defaults aren't good enough */
			if ((extpath = get_extpath())) {
				for (cp = strtok(extpath, DIR_SEP); cp; cp = strtok(NULL, DIR_SEP)) {
					/* strip trailing slashes */
					int len = strlen(cp);
					if (len)
						while (cp[--len] == '/' && len)
							cp[len] = 0;
					/* we do the redundancy check only if cache usage is enabled */
					if (strcmp(UCLIBC_RUNTIME_PREFIX "lib", cp) == 0
					    || strcmp(UCLIBC_RUNTIME_PREFIX "usr/lib", cp) == 0) {
						if (verbose >= 0)
							warnx("You should remove `%s' from `%s'", cp, LDSO_CONF);
						continue;
					}
					scan_dir(cp);
				}
				free(extpath);
			}
#endif
		}

		if (!nocache)
			cache_write();
	}

	exit(EXIT_SUCCESS);
}