udev / src / libudev-util-private.c

/*
 * libudev - interface to udev device information
 *
 * Copyright (C) 2003-2009 Kay Sievers <kay.sievers@vrfy.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 */

#include <stdlib.h>
#include <stdio.h>
#include <stddef.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <pwd.h>
#include <grp.h>
#include <sys/param.h>

#include "libudev.h"
#include "libudev-private.h"

static int create_path(struct udev *udev, const char *path, bool selinux)
{
        char p[UTIL_PATH_SIZE];
        char *pos;
        struct stat stats;
        int err;

        util_strscpy(p, sizeof(p), path);
        pos = strrchr(p, '/');
        if (pos == NULL)
                return 0;
        while (pos != p && pos[-1] == '/')
                pos--;
        if (pos == p)
                return 0;
        pos[0] = '\0';

        dbg(udev, "stat '%s'\n", p);
        if (stat(p, &stats) == 0) {
                if ((stats.st_mode & S_IFMT) == S_IFDIR)
                        return 0;
                else
                        return -ENOTDIR;
        }

        err = util_create_path(udev, p);
        if (err != 0)
                return err;

        dbg(udev, "mkdir '%s'\n", p);
        if (selinux)
                udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
        err = mkdir(p, 0755);
        if (err != 0) {
                err = -errno;
                if (err == -EEXIST && stat(p, &stats) == 0) {
                        if ((stats.st_mode & S_IFMT) == S_IFDIR)
                                err = 0;
                        else
                                err = -ENOTDIR;
                }
        }
        if (selinux)
                udev_selinux_resetfscreatecon(udev);
        return err;
}

int util_create_path(struct udev *udev, const char *path)
{
        return create_path(udev, path, false);
}

int util_create_path_selinux(struct udev *udev, const char *path)
{
        return create_path(udev, path, true);
}

int util_delete_path(struct udev *udev, const char *path)
{
        char p[UTIL_PATH_SIZE];
        char *pos;
        int err = 0;

        if (path[0] == '/')
                while(path[1] == '/')
                        path++;
        util_strscpy(p, sizeof(p), path);
        pos = strrchr(p, '/');
        if (pos == p || pos == NULL)
                return 0;

        for (;;) {
                *pos = '\0';
                pos = strrchr(p, '/');

                /* don't remove the last one */
                if ((pos == p) || (pos == NULL))
                        break;

                err = rmdir(p);
                if (err < 0) {
                        if (errno == ENOENT)
                                err = 0;
                        break;
                }
        }
        return err;
}

uid_t util_lookup_user(struct udev *udev, const char *user)
{
        char *endptr;
        struct passwd pwbuf;
        struct passwd *pw;
        uid_t uid;
        size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
        char *buf = alloca(buflen);

        if (strcmp(user, "root") == 0)
                return 0;
        uid = strtoul(user, &endptr, 10);
        if (endptr[0] == '\0')
                return uid;

        errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
        if (pw != NULL)
                return pw->pw_uid;
        if (errno == 0 || errno == ENOENT || errno == ESRCH)
                err(udev, "specified user '%s' unknown\n", user);
        else
                err(udev, "error resolving user '%s': %m\n", user);
        return 0;
}

gid_t util_lookup_group(struct udev *udev, const char *group)
{
        char *endptr;
        struct group grbuf;
        struct group *gr;
        gid_t gid = 0;
        size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
        char *buf = alloca(buflen);

        if (strcmp(group, "root") == 0)
                return 0;
        gid = strtoul(group, &endptr, 10);
        if (endptr[0] == '\0')
                return gid;
        buf = NULL;
        gid = 0;
        for (;;) {
                char *newbuf;

                newbuf = realloc(buf, buflen);
                if (!newbuf)
                        break;
                buf = newbuf;
                errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
                if (gr != NULL) {
                        gid = gr->gr_gid;
                } else if (errno == ERANGE) {
                        buflen *= 2;
                        continue;
                } else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
                        err(udev, "specified group '%s' unknown\n", group);
                } else {
                        err(udev, "error resolving group '%s': %m\n", group);
                }
                break;
        }
        free(buf);
        return gid;
}

/* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
int util_resolve_subsys_kernel(struct udev *udev, const char *string,
                               char *result, size_t maxsize, int read_value)
{
        char temp[UTIL_PATH_SIZE];
        char *subsys;
        char *sysname;
        struct udev_device *dev;
        char *attr;

        if (string[0] != '[')
                return -1;

        util_strscpy(temp, sizeof(temp), string);

        subsys = &temp[1];

        sysname = strchr(subsys, '/');
        if (sysname == NULL)
                return -1;
        sysname[0] = '\0';
        sysname = &sysname[1];

        attr = strchr(sysname, ']');
        if (attr == NULL)
                return -1;
        attr[0] = '\0';
        attr = &attr[1];
        if (attr[0] == '/')
                attr = &attr[1];
        if (attr[0] == '\0')
                attr = NULL;

        if (read_value && attr == NULL)
                return -1;

        dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
        if (dev == NULL)
                return -1;

        if (read_value) {
                const char *val;

                val = udev_device_get_sysattr_value(dev, attr);
                if (val != NULL)
                        util_strscpy(result, maxsize, val);
                else
                        result[0] = '\0';
                info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
        } else {
                size_t l;
                char *s;

                s = result;
                l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
                if (attr != NULL)
                        util_strpcpyl(&s, l, "/", attr, NULL);
                info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
        }
        udev_device_unref(dev);
        return 0;
}
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