busybox

/* vi: set sw=4 ts=4: */

/*

 * Copyright (C) 2014 Tito Ragusa <farmatito@tiscali.it>

 *

 * Licensed under GPLv2 or later, see file LICENSE in this source tree.

 */

/* This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY!!

 *

 * Rewrite of some parts. Main differences are:

 *

 * 1) the buffer for getpwuid, getgrgid, getpwnam, getgrnam is dynamically

 *    allocated.

 *    If ENABLE_FEATURE_CLEAN_UP is set the buffers are freed at program

 *    exit using the atexit function to make valgrind happy.

 * 2) the passwd/group files:

 *      a) must contain the expected number of fields (as per count of field

 *         delimiters ":") or we will complain with a error message.

 *      b) leading and trailing whitespace in fields is stripped.

 *      c) some fields are not allowed to be empty (e.g. username, uid/gid),

 *         and in this case NULL is returned and errno is set to EINVAL.

 *         This behaviour could be easily changed by modifying PW_DEF, GR_DEF,

 *         SP_DEF strings (uppercase makes a field mandatory).

 *      d) the string representing uid/gid must be convertible by strtoXX

 *         functions, or errno is set to EINVAL.

 *      e) leading and trailing whitespace in group member names is stripped.

 * 3) the internal function for getgrouplist uses dynamically allocated buffer.

 * 4) at the moment only the functions really used by busybox code are

 *    implemented, if you need a particular missing function it should be

 *    easy to write it by using the internal common code.

 */

#include "libbb.h"

​

struct const_passdb {

    const char *filename;

    char def[7 + 2*ENABLE_USE_BB_SHADOW];

    uint8_t off[7 + 2*ENABLE_USE_BB_SHADOW];

    uint8_t numfields;

    uint8_t size_of;

};

struct passdb {

    const char *filename;

    char def[7 + 2*ENABLE_USE_BB_SHADOW];

    uint8_t off[7 + 2*ENABLE_USE_BB_SHADOW];

    uint8_t numfields;

    uint8_t size_of;

    FILE *fp;

    char *malloced;

};

/* Note: for shadow db, def[] will not contain terminating NUL,

 * but convert_to_struct() logic detects def[] end by "less than SP?",

 * not by "is it NUL?" condition; and off[0] happens to be zero

 * for every db anyway, so there _is_ in fact a terminating NUL there.

 */

​

/* S = string not empty, s = string maybe empty,

 * I = uid,gid, l = long maybe empty, m = members,

 * r = reserved

 */

#define PW_DEF "SsIIsss"

#define GR_DEF "SsIm"

#define SP_DEF "Ssllllllr"

​

static const struct const_passdb const_pw_db = {

    _PATH_PASSWD, PW_DEF,

    {

        offsetof(struct passwd, pw_name),       /* 0 S */

        offsetof(struct passwd, pw_passwd),     /* 1 s */

        offsetof(struct passwd, pw_uid),        /* 2 I */

        offsetof(struct passwd, pw_gid),        /* 3 I */

        offsetof(struct passwd, pw_gecos),      /* 4 s */

        offsetof(struct passwd, pw_dir),        /* 5 s */

        offsetof(struct passwd, pw_shell)       /* 6 s */

    },

    sizeof(PW_DEF)-1, sizeof(struct passwd)

};

static const struct const_passdb const_gr_db = {

    _PATH_GROUP, GR_DEF,

    {

        offsetof(struct group, gr_name),        /* 0 S */

        offsetof(struct group, gr_passwd),      /* 1 s */

        offsetof(struct group, gr_gid),         /* 2 I */

        offsetof(struct group, gr_mem)          /* 3 m (char **) */

    },

    sizeof(GR_DEF)-1, sizeof(struct group)

};

#if ENABLE_USE_BB_SHADOW

static const struct const_passdb const_sp_db = {

    _PATH_SHADOW, SP_DEF,

    {

        offsetof(struct spwd, sp_namp),         /* 0 S Login name */

        offsetof(struct spwd, sp_pwdp),         /* 1 s Encrypted password */