ldconfig.c

linux下用PCMCIA无线网卡虚拟无线AP的程序源码

	/* 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: uClibc version\n", argv[0]);

    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);
	    }

	    scan_dir(UCLIBC_TARGET_PREFIX "/usr/lib");
	    scan_dir(UCLIBC_TARGET_PREFIX "/lib");
	}

	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);
}