gnu/usr.bin/ld/shlib.c

/*
 * $Id: shlib.c,v 1.4 1993/12/02 00:56:40 jkh Exp $
 */

#include <sys/param.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/time.h>
#include <fcntl.h>
#include <string.h>
#include <dirent.h>
#include <a.out.h>

#include "ld.h"

/*
 * Standard directories to search for files specified by -l.
 */
#ifndef STANDARD_SEARCH_DIRS
#define STANDARD_SEARCH_DIRS    "/usr/lib", "/usr/local/lib"
#endif

char *standard_search_dirs[] = {
        STANDARD_SEARCH_DIRS
};

int n_search_dirs;

void
add_search_dir(name)
        char    *name;
{
        n_search_dirs++;
        search_dirs = (char **)xrealloc(search_dirs,
                                n_search_dirs * sizeof(char *));
        search_dirs[n_search_dirs - 1] = strdup(name);
}

void
std_search_dirs(paths)
char    *paths;
{
        char    *cp;
        int     i, n;

        if (paths != NULL)
                /* Add search directories from `paths' */
                while ((cp = strsep(&paths, ":")) != NULL) {
                        add_search_dir(cp);
                        if (paths)
                                *(paths-1) = ':';
                }

        /* Append standard search directories */
        n = sizeof standard_search_dirs / sizeof standard_search_dirs[0];
        for (i = 0; i < n; i++)
                add_search_dir(standard_search_dirs[i]);
}

/*
 * Return true if CP points to a valid dewey number.
 * Decode and leave the result in the array DEWEY.
 * Return the number of decoded entries in DEWEY.
 */

int
getdewey(dewey, cp)
int     dewey[];
char    *cp;
{
        int     i, n;

        for (n = 0, i = 0; i < MAXDEWEY; i++) {
                if (*cp == '\0')
                        break;

                if (*cp == '.') cp++;
                if (!isdigit(*cp))
                        return 0;

                dewey[n++] = strtol(cp, &cp, 10);
        }

        return n;
}

/*
 * Compare two dewey arrays.
 * Return -1 if `d1' represents a smaller value than `d2'.
 * Return  1 if `d1' represents a greater value than `d2'.
 * Return  0 if equal.
 */
int
cmpndewey(d1, n1, d2, n2)
int     d1[], d2[];
int     n1, n2;
{
        int     i;

        for (i = 0; i < n1 && i < n2; i++) {
                if (d1[i] < d2[i])
                        return -1;
                if (d1[i] > d2[i])
                        return 1;
        }

        if (n1 == n2)
                return 0;

        if (i == n1)
                return -1;

        if (i == n2)
                return 1;
}

/*
 * Search directories for a shared library matching the given
 * major and minor version numbers.
 *
 * MAJOR == -1 && MINOR == -1   --> find highest version
 * MAJOR != -1 && MINOR == -1   --> find highest minor version
 * MAJOR == -1 && MINOR != -1   --> invalid
 * MAJOR != -1 && MINOR != -1   --> find highest micro version
 */

/* Not interested in devices right now... */
#undef major
#undef minor

char *
findshlib(name, majorp, minorp)
char    *name;
int     *majorp, *minorp;
{
        int             dewey[MAXDEWEY];
        int             ndewey;
        int             tmp[MAXDEWEY];
        int             i;
        int             len;
        char            *lname, *path = NULL;
        int             major = *majorp, minor = *minorp;

        len = strlen(name);
        lname = (char *)alloca(len + sizeof("lib"));
        sprintf(lname, "lib%s", name);
        len += 3;

        ndewey = 0;

        for (i = 0; i < n_search_dirs; i++) {
                DIR             *dd = opendir(search_dirs[i]);
                struct dirent   *dp;

                if (dd == NULL)
                        continue;

                while ((dp = readdir(dd)) != NULL) {
                        int     n, j, might_take_it = 0;

                        if (dp->d_namlen < len + 4)
                                continue;
                        if (strncmp(dp->d_name, lname, len) != 0)
                                continue;
                        if (strncmp(dp->d_name+len, ".so.", 4) != 0)
                                continue;

                        if ((n = getdewey(tmp, dp->d_name+len+4)) == 0)
                                continue;

                        if (major == -1 && minor == -1) {
                                might_take_it = 1;
                        } else if (major != -1 && minor == -1) {
                                if (tmp[0] == major)
                                        might_take_it = 1;
                        } else if (major != -1 && minor != -1) {
                                if (tmp[0] == major)
                                        if (n == 1 || tmp[1] >= minor)
                                                might_take_it = 1;
                        }

                        if (!might_take_it)
                                continue;

                        if (cmpndewey(tmp, n, dewey, ndewey) <= 0)
                                continue;

                        /* We have a better version */
                        if (path)
                                free(path);
                        path = concat(search_dirs[i], "/", dp->d_name);
                        bcopy(tmp, dewey, sizeof(dewey));
                        ndewey = n;
                        *majorp = dewey[0];
                        *minorp = dewey[1];
                }
                closedir(dd);
        }

        return path;
}