/* vi: set sw=4 ts=4: */
/*  Copyright (C) 2003     Manuel Novoa III
 *
 *  Licensed under GPL v2, or later.  See file LICENSE in this tarball.
 */

/*  Nov 6, 2003  Initial version.
 *
 *  NOTE: This implementation is quite strict about requiring all
 *    field seperators.  It also does not allow leading whitespace
 *    except when processing the numeric fields.  glibc is more
 *    lenient.  See the various glibc difference comments below.
 *
 *  TODO:
 *    Move to dynamic allocation of (currently statically allocated)
 *      buffers; especially for the group-related functions since
 *      large group member lists will cause error returns.
 *
 */

#include "libbb.h"
#include <assert.h>

#ifndef _PATH_SHADOW
#define _PATH_SHADOW    "/etc/shadow"
#endif
#ifndef _PATH_PASSWD
#define _PATH_PASSWD    "/etc/passwd"
#endif
#ifndef _PATH_GROUP
#define _PATH_GROUP     "/etc/group"
#endif

/**********************************************************************/
/* Sizes for statically allocated buffers. */

/* If you change these values, also change _SC_GETPW_R_SIZE_MAX and
 * _SC_GETGR_R_SIZE_MAX in libc/unistd/sysconf.c to match */
#define PWD_BUFFER_SIZE 256
#define GRP_BUFFER_SIZE 256

/**********************************************************************/
/* Prototypes for internal functions. */

static int bb__pgsreader(
                int FAST_FUNC (*parserfunc)(void *d, char *line),
                void *data,
                char *__restrict line_buff,
                size_t buflen,
                FILE *f);

static int FAST_FUNC bb__parsepwent(void *pw, char *line);
static int FAST_FUNC bb__parsegrent(void *gr, char *line);
#if ENABLE_USE_BB_SHADOW
static int FAST_FUNC bb__parsespent(void *sp, char *line);
#endif

/**********************************************************************/
/* We avoid having big global data. */

struct statics {
        /* Smaller things first */
        struct passwd getpwuid_resultbuf;
        struct group getgrgid_resultbuf;
        struct passwd getpwnam_resultbuf;
        struct group getgrnam_resultbuf;

        char getpwuid_buffer[PWD_BUFFER_SIZE];
        char getgrgid_buffer[GRP_BUFFER_SIZE];
        char getpwnam_buffer[PWD_BUFFER_SIZE];
        char getgrnam_buffer[GRP_BUFFER_SIZE];
#if 0
        struct passwd fgetpwent_resultbuf;
        struct group fgetgrent_resultbuf;
        struct spwd fgetspent_resultbuf;
        char fgetpwent_buffer[PWD_BUFFER_SIZE];
        char fgetgrent_buffer[GRP_BUFFER_SIZE];
        char fgetspent_buffer[PWD_BUFFER_SIZE];
#endif
#if 0 //ENABLE_USE_BB_SHADOW
        struct spwd getspuid_resultbuf;
        struct spwd getspnam_resultbuf;
        char getspuid_buffer[PWD_BUFFER_SIZE];
        char getspnam_buffer[PWD_BUFFER_SIZE];
#endif
// Not converted - too small to bother
//pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
//FILE *pwf /*= NULL*/;
//FILE *grf /*= NULL*/;
//FILE *spf /*= NULL*/;
#if 0
        struct passwd getpwent_pwd;
        struct group getgrent_gr;
        char getpwent_line_buff[PWD_BUFFER_SIZE];
        char getgrent_line_buff[GRP_BUFFER_SIZE];
#endif
#if 0 //ENABLE_USE_BB_SHADOW
        struct spwd getspent_spwd;
        struct spwd sgetspent_spwd;
        char getspent_line_buff[PWD_BUFFER_SIZE];
        char sgetspent_line_buff[PWD_BUFFER_SIZE];
#endif
};

static struct statics *ptr_to_statics;

static struct statics *get_S(void)
{
        if (!ptr_to_statics)
                ptr_to_statics = xzalloc(sizeof(*ptr_to_statics));
        return ptr_to_statics;
}

/* Always use in this order, get_S() must be called first */
#define RESULTBUF(name) &((S = get_S())->name##_resultbuf)
#define BUFFER(name)    (S->name##_buffer)

/**********************************************************************/
/* For the various fget??ent_r funcs, return
 *
 *  0: success
 *  ENOENT: end-of-file encountered
 *  ERANGE: buflen too small
 *  other error values possible. See bb__pgsreader.
 *
 * Also, *result == resultbuf on success and NULL on failure.
 *
 * NOTE: glibc difference - For the ENOENT case, glibc also sets errno.
 *   We do not, as it really isn't an error if we reach the end-of-file.
 *   Doing so is analogous to having fgetc() set errno on EOF.
 */
/**********************************************************************/

int fgetpwent_r(FILE *__restrict stream, struct passwd *__restrict resultbuf,
                                char *__restrict buffer, size_t buflen,
                                struct passwd **__restrict result)
{
        int rv;

        *result = NULL;

        rv = bb__pgsreader(bb__parsepwent, resultbuf, buffer, buflen, stream);
        if (!rv) {
                *result = resultbuf;
        }

        return rv;
}

int fgetgrent_r(FILE *__restrict stream, struct group *__restrict resultbuf,
                                char *__restrict buffer, size_t buflen,
                                struct group **__restrict result)
{
        int rv;

        *result = NULL;

        rv = bb__pgsreader(bb__parsegrent, resultbuf, buffer, buflen, stream);
        if (!rv) {
                *result = resultbuf;
        }

        return rv;
}

#if ENABLE_USE_BB_SHADOW
#ifdef UNUSED_FOR_NOW
int fgetspent_r(FILE *__restrict stream, struct spwd *__restrict resultbuf,
                                char *__restrict buffer, size_t buflen,
                                struct spwd **__restrict result)
{
        int rv;

        *result = NULL;

        rv = bb__pgsreader(bb__parsespent, resultbuf, buffer, buflen, stream);
        if (!rv) {
                *result = resultbuf;
        }

        return rv;
}
#endif
#endif

/**********************************************************************/
/* For the various fget??ent funcs, return NULL on failure and a
 * pointer to the appropriate struct (statically allocated) on success.
 * TODO: audit & stop using these in bbox, they pull in static buffers */
/**********************************************************************/

#ifdef UNUSED_SINCE_WE_AVOID_STATIC_BUFS
struct passwd *fgetpwent(FILE *stream)
{
        struct statics *S;
        struct passwd *resultbuf = RESULTBUF(fgetpwent);
        char *buffer = BUFFER(fgetpwent);
        struct passwd *result;

        fgetpwent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetpwent)), &result);
        return result;
}

struct group *fgetgrent(FILE *stream)
{
        struct statics *S;
        struct group *resultbuf = RESULTBUF(fgetgrent);
        char *buffer = BUFFER(fgetgrent);
        struct group *result;

        fgetgrent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetgrent)), &result);
        return result;
}
#endif

#if ENABLE_USE_BB_SHADOW
#ifdef UNUSED_SINCE_WE_AVOID_STATIC_BUFS
struct spwd *fgetspent(FILE *stream)
{
        struct statics *S;
        struct spwd *resultbuf = RESULTBUF(fgetspent);
        char *buffer = BUFFER(fgetspent);
        struct spwd *result;

        fgetspent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetspent)), &result);
        return result;
}
#endif

#ifdef UNUSED_FOR_NOW
int sgetspent_r(const char *string, struct spwd *result_buf,
                                char *buffer, size_t buflen, struct spwd **result)
{
        int rv = ERANGE;

        *result = NULL;

        if (buflen < PWD_BUFFER_SIZE) {
 DO_ERANGE:
                errno = rv;
                goto DONE;
        }

        if (string != buffer) {
                if (strlen(string) >= buflen) {
                        goto DO_ERANGE;
                }
                strcpy(buffer, string);
        }

        rv = bb__parsespent(result_buf, buffer);
        if (!rv) {
                *result = result_buf;
        }

 DONE:
        return rv;
}
#endif
#endif /* ENABLE_USE_BB_SHADOW */

/**********************************************************************/

#define GETXXKEY_R_FUNC         getpwnam_r
#define GETXXKEY_R_PARSER       bb__parsepwent
#define GETXXKEY_R_ENTTYPE      struct passwd
#define GETXXKEY_R_TEST(ENT)    (!strcmp((ENT)->pw_name, key))
#define GETXXKEY_R_KEYTYPE      const char *__restrict
#define GETXXKEY_R_PATHNAME     _PATH_PASSWD
#include "pwd_grp_internal.c"

#define GETXXKEY_R_FUNC         getgrnam_r
#define GETXXKEY_R_PARSER       bb__parsegrent
#define GETXXKEY_R_ENTTYPE      struct group
#define GETXXKEY_R_TEST(ENT)    (!strcmp((ENT)->gr_name, key))
#define GETXXKEY_R_KEYTYPE      const char *__restrict
#define GETXXKEY_R_PATHNAME     _PATH_GROUP
#include "pwd_grp_internal.c"

#if ENABLE_USE_BB_SHADOW
#define GETXXKEY_R_FUNC         getspnam_r
#define GETXXKEY_R_PARSER       bb__parsespent
#define GETXXKEY_R_ENTTYPE      struct spwd
#define GETXXKEY_R_TEST(ENT)    (!strcmp((ENT)->sp_namp, key))
#define GETXXKEY_R_KEYTYPE      const char *__restrict
#define GETXXKEY_R_PATHNAME     _PATH_SHADOW
#include "pwd_grp_internal.c"
#endif

#define GETXXKEY_R_FUNC         getpwuid_r
#define GETXXKEY_R_PARSER       bb__parsepwent
#define GETXXKEY_R_ENTTYPE      struct passwd
#define GETXXKEY_R_TEST(ENT)    ((ENT)->pw_uid == key)
#define GETXXKEY_R_KEYTYPE      uid_t
#define GETXXKEY_R_PATHNAME     _PATH_PASSWD
#include "pwd_grp_internal.c"

#define GETXXKEY_R_FUNC         getgrgid_r
#define GETXXKEY_R_PARSER       bb__parsegrent
#define GETXXKEY_R_ENTTYPE      struct group
#define GETXXKEY_R_TEST(ENT)    ((ENT)->gr_gid == key)
#define GETXXKEY_R_KEYTYPE      gid_t
#define GETXXKEY_R_PATHNAME     _PATH_GROUP
#include "pwd_grp_internal.c"

/**********************************************************************/
/* TODO: audit & stop using these in bbox, they pull in static buffers */

/* This one has many users */
struct passwd *getpwuid(uid_t uid)
{
        struct statics *S;
        struct passwd *resultbuf = RESULTBUF(getpwuid);
        char *buffer = BUFFER(getpwuid);
        struct passwd *result;

        getpwuid_r(uid, resultbuf, buffer, sizeof(BUFFER(getpwuid)), &result);
        return result;
}

/* This one has many users */
struct group *getgrgid(gid_t gid)
{
        struct statics *S;
        struct group *resultbuf = RESULTBUF(getgrgid);
        char *buffer = BUFFER(getgrgid);
        struct group *result;

        getgrgid_r(gid, resultbuf, buffer, sizeof(BUFFER(getgrgid)), &result);
        return result;
}

#if 0 //ENABLE_USE_BB_SHADOW
/* This function is non-standard and is currently not built.  It seems
 * to have been created as a reentrant version of the non-standard
 * functions getspuid.  Why getspuid was added, I do not know. */
int getspuid_r(uid_t uid, struct spwd *__restrict resultbuf,
                       char *__restrict buffer, size_t buflen,
                       struct spwd **__restrict result)
{
        int rv;
        struct passwd *pp;
        struct passwd password;
        char pwd_buff[PWD_BUFFER_SIZE];

        *result = NULL;
        rv = getpwuid_r(uid, &password, pwd_buff, sizeof(pwd_buff), &pp);
        if (!rv) {
                rv = getspnam_r(password.pw_name, resultbuf, buffer, buflen, result);
        }

        return rv;
}

/* This function is non-standard and is currently not built.
 * Why it was added, I do not know. */
struct spwd *getspuid(uid_t uid)
{
        struct statics *S;
        struct spwd *resultbuf = RESULTBUF(getspuid);
        char *buffer = BUFFER(getspuid);
        struct spwd *result;

        getspuid_r(uid, resultbuf, buffer, sizeof(BUFFER(getspuid)), &result);
        return result;
}
#endif

/* This one has many users */
struct passwd *getpwnam(const char *name)
{
        struct statics *S;
        struct passwd *resultbuf = RESULTBUF(getpwnam);
        char *buffer = BUFFER(getpwnam);
        struct passwd *result;

        getpwnam_r(name, resultbuf, buffer, sizeof(BUFFER(getpwnam)), &result);
        return result;
}

/* This one has many users */
struct group *getgrnam(const char *name)
{
        struct statics *S;
        struct group *resultbuf = RESULTBUF(getgrnam);
        char *buffer = BUFFER(getgrnam);
        struct group *result;

        getgrnam_r(name, resultbuf, buffer, sizeof(BUFFER(getgrnam)), &result);
        return result;
}

#if 0 //ENABLE_USE_BB_SHADOW
struct spwd *getspnam(const char *name)
{
        struct statics *S;
        struct spwd *resultbuf = RESULTBUF(getspnam);
        char *buffer = BUFFER(getspnam);
        struct spwd *result;

        getspnam_r(name, resultbuf, buffer, sizeof(BUFFER(getspnam)), &result);
        return result;
}
#endif

/**********************************************************************/

/* FIXME: we don't have such CONFIG_xx - ?! */

#if defined CONFIG_USE_BB_THREADSAFE_SHADOW && defined PTHREAD_MUTEX_INITIALIZER
static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
# define LOCK           pthread_mutex_lock(&mylock)
# define UNLOCK         pthread_mutex_unlock(&mylock);
#else
# define LOCK           ((void) 0)
# define UNLOCK         ((void) 0)
#endif

static FILE *pwf /*= NULL*/;
void setpwent(void)
{
        LOCK;
        if (pwf) {
                rewind(pwf);
        }
        UNLOCK;
}

void endpwent(void)
{
        LOCK;
        if (pwf) {
                fclose(pwf);
                pwf = NULL;
        }
        UNLOCK;
}


int getpwent_r(struct passwd *__restrict resultbuf,
                           char *__restrict buffer, size_t buflen,
                           struct passwd **__restrict result)
{
        int rv;

        LOCK;
        *result = NULL;                         /* In case of error... */

        if (!pwf) {
                pwf = fopen_for_read(_PATH_PASSWD);
                if (!pwf) {
                        rv = errno;
                        goto ERR;
                }
        }

        rv = bb__pgsreader(bb__parsepwent, resultbuf, buffer, buflen, pwf);
        if (!rv) {
                *result = resultbuf;
        }

 ERR:
        UNLOCK;
        return rv;
}

static FILE *grf /*= NULL*/;
void setgrent(void)
{
        LOCK;
        if (grf) {
                rewind(grf);
        }
        UNLOCK;
}

void endgrent(void)
{
        LOCK;
        if (grf) {
                fclose(grf);
                grf = NULL;
        }
        UNLOCK;
}

int getgrent_r(struct group *__restrict resultbuf,
                           char *__restrict buffer, size_t buflen,
                           struct group **__restrict result)
{
        int rv;

        LOCK;
        *result = NULL;                         /* In case of error... */

        if (!grf) {
                grf = fopen_for_read(_PATH_GROUP);
                if (!grf) {
                        rv = errno;
                        goto ERR;
                }
        }

        rv = bb__pgsreader(bb__parsegrent, resultbuf, buffer, buflen, grf);
        if (!rv) {
                *result = resultbuf;
        }

 ERR:
        UNLOCK;
        return rv;
}

#ifdef UNUSED_FOR_NOW
#if ENABLE_USE_BB_SHADOW
static FILE *spf /*= NULL*/;
void setspent(void)
{
        LOCK;
        if (spf) {
                rewind(spf);
        }
        UNLOCK;
}

void endspent(void)
{
        LOCK;
        if (spf) {
                fclose(spf);
                spf = NULL;
        }
        UNLOCK;
}

int getspent_r(struct spwd *resultbuf, char *buffer,
                           size_t buflen, struct spwd **result)
{
        int rv;

        LOCK;
        *result = NULL;                         /* In case of error... */

        if (!spf) {
                spf = fopen_for_read(_PATH_SHADOW);
                if (!spf) {
                        rv = errno;
                        goto ERR;
                }
        }

        rv = bb__pgsreader(bb__parsespent, resultbuf, buffer, buflen, spf);
        if (!rv) {
                *result = resultbuf;
        }

 ERR:
        UNLOCK;
        return rv;
}
#endif
#endif /* UNUSED_FOR_NOW */

#ifdef UNUSED_SINCE_WE_AVOID_STATIC_BUFS
struct passwd *getpwent(void)
{
        static char line_buff[PWD_BUFFER_SIZE];
        static struct passwd pwd;
        struct passwd *result;

        getpwent_r(&pwd, line_buff, sizeof(line_buff), &result);
        return result;
}

struct group *getgrent(void)
{
        static char line_buff[GRP_BUFFER_SIZE];
        static struct group gr;
        struct group *result;

        getgrent_r(&gr, line_buff, sizeof(line_buff), &result);
        return result;
}

#if ENABLE_USE_BB_SHADOW
struct spwd *getspent(void)
{
        static char line_buff[PWD_BUFFER_SIZE];
        static struct spwd spwd;
        struct spwd *result;

        getspent_r(&spwd, line_buff, sizeof(line_buff), &result);
        return result;
}

struct spwd *sgetspent(const char *string)
{
        static char line_buff[PWD_BUFFER_SIZE];
        static struct spwd spwd;
        struct spwd *result;

        sgetspent_r(string, &spwd, line_buff, sizeof(line_buff), &result);
        return result;
}
#endif
#endif /* UNUSED_SINCE_WE_AVOID_STATIC_BUFS */

static gid_t *getgrouplist_internal(int *ngroups_ptr, const char *user, gid_t gid)
{
        FILE *grfile;
        gid_t *group_list;
        int ngroups;
        struct group group;
        char buff[PWD_BUFFER_SIZE];

        /* We alloc space for 8 gids at a time. */
        group_list = xmalloc(8 * sizeof(group_list[0]));
        group_list[0] = gid;
        ngroups = 1;

        grfile = fopen_for_read(_PATH_GROUP);
        if (grfile) {
                while (!bb__pgsreader(bb__parsegrent, &group, buff, sizeof(buff), grfile)) {
                        char **m;
                        assert(group.gr_mem); /* Must have at least a NULL terminator. */
                        if (group.gr_gid == gid)
                                continue;
                        for (m = group.gr_mem; *m; m++) {
                                if (strcmp(*m, user) != 0)
                                        continue;
                                group_list = xrealloc_vector(group_list, /*8=2^3:*/ 3, ngroups);
                                group_list[ngroups++] = group.gr_gid;
                                break;
                        }
                }
                fclose(grfile);
        }
        *ngroups_ptr = ngroups;
        return group_list;
}

int initgroups(const char *user, gid_t gid)
{
        int ngroups;
        gid_t *group_list = getgrouplist_internal(&ngroups, user, gid);

        ngroups = setgroups(ngroups, group_list);
        free(group_list);
        return ngroups;
}

int getgrouplist(const char *user, gid_t gid, gid_t *groups, int *ngroups)
{
        int ngroups_old = *ngroups;
        gid_t *group_list = getgrouplist_internal(ngroups, user, gid);

        if (*ngroups <= ngroups_old) {
                ngroups_old = *ngroups;
                memcpy(groups, group_list, ngroups_old * sizeof(groups[0]));
        } else {
                ngroups_old = -1;
        }
        free(group_list);
        return ngroups_old;
}

#ifdef UNUSED_SINCE_WE_AVOID_STATIC_BUFS
int putpwent(const struct passwd *__restrict p, FILE *__restrict f)
{
        int rv = -1;

#if 0
        /* glibc does this check */
        if (!p || !f) {
                errno = EINVAL;
                return rv;
        }
#endif

        /* No extra thread locking is needed above what fprintf does. */
        if (fprintf(f, "%s:%s:%lu:%lu:%s:%s:%s\n",
                                p->pw_name, p->pw_passwd,
                                (unsigned long)(p->pw_uid),
                                (unsigned long)(p->pw_gid),
                                p->pw_gecos, p->pw_dir, p->pw_shell) >= 0
                ) {
                rv = 0;
        }

        return rv;
}

int putgrent(const struct group *__restrict p, FILE *__restrict f)
{
        int rv = -1;

#if 0
        /* glibc does this check */
        if (!p || !f) {
                errno = EINVAL;
                return rv;
        }
#endif

        if (fprintf(f, "%s:%s:%lu:",
                                p->gr_name, p->gr_passwd,
                                (unsigned long)(p->gr_gid)) >= 0
        ) {
                static const char format[] ALIGN1 = ",%s";

                char **m;
                const char *fmt;

                fmt = format + 1;

                assert(p->gr_mem);
                m = p->gr_mem;

                while (1) {
                        if (!*m) {
                                if (fputc('\n', f) >= 0) {
                                        rv = 0;
                                }
                                break;
                        }
                        if (fprintf(f, fmt, *m) < 0) {
                                break;
                        }
                        m++;
                        fmt = format;
                }
        }

        return rv;
}
#endif

#if ENABLE_USE_BB_SHADOW
#ifdef UNUSED_FOR_NOW
static const unsigned char put_sp_off[] ALIGN1 = {
        offsetof(struct spwd, sp_lstchg),       /* 2 - not a char ptr */
        offsetof(struct spwd, sp_min),          /* 3 - not a char ptr */
        offsetof(struct spwd, sp_max),          /* 4 - not a char ptr */
        offsetof(struct spwd, sp_warn),         /* 5 - not a char ptr */
        offsetof(struct spwd, sp_inact),        /* 6 - not a char ptr */
        offsetof(struct spwd, sp_expire)        /* 7 - not a char ptr */
};

int putspent(const struct spwd *p, FILE *stream)
{
        const char *fmt;
        long x;
        int i;
        int rv = -1;

        /* Unlike putpwent and putgrent, glibc does not check the args. */
        if (fprintf(stream, "%s:%s:", p->sp_namp,
                                (p->sp_pwdp ? p->sp_pwdp : "")) < 0
        ) {
                goto DO_UNLOCK;
        }

        for (i = 0; i < sizeof(put_sp_off); i++) {
                fmt = "%ld:";
                x = *(long *)((char *)p + put_sp_off[i]);
                if (x == -1) {
                        fmt += 3;
                }
                if (fprintf(stream, fmt, x) < 0) {
                        goto DO_UNLOCK;
                }
        }

        if ((p->sp_flag != ~0UL) && (fprintf(stream, "%lu", p->sp_flag) < 0)) {
                goto DO_UNLOCK;
        }

        if (fputc('\n', stream) > 0) {
                rv = 0;
        }

 DO_UNLOCK:
        return rv;
}
#endif
#endif /* USE_BB_SHADOW */

/**********************************************************************/
/* Internal functions                                                 */
/**********************************************************************/

static const unsigned char pw_off[] ALIGN1 = {
        offsetof(struct passwd, pw_name),       /* 0 */
        offsetof(struct passwd, pw_passwd),     /* 1 */
        offsetof(struct passwd, pw_uid),        /* 2 - not a char ptr */
        offsetof(struct passwd, pw_gid),        /* 3 - not a char ptr */
        offsetof(struct passwd, pw_gecos),      /* 4 */
        offsetof(struct passwd, pw_dir),        /* 5 */
        offsetof(struct passwd, pw_shell)       /* 6 */
};

static int FAST_FUNC bb__parsepwent(void *data, char *line)
{
        char *endptr;
        char *p;
        int i;

        i = 0;
        while (1) {
                p = (char *) data + pw_off[i];

                if (i < 2 || i > 3) {
                        *((char **) p) = line;
                        if (i == 6) {
                                return 0;
                        }
                        /* NOTE: glibc difference - glibc allows omission of
                         * ':' seperators after the gid field if all remaining
                         * entries are empty.  We require all separators. */
                        line = strchr(line, ':');
                        if (!line) {
                                break;
                        }
                } else {
                        unsigned long t = strtoul(line, &endptr, 10);
                        /* Make sure we had at least one digit, and that the
                         * failing char is the next field seperator ':'.  See
                         * glibc difference note above. */
                        /* TODO: Also check for leading whitespace? */
                        if ((endptr == line) || (*endptr != ':')) {
                                break;
                        }
                        line = endptr;
                        if (i & 1) {            /* i == 3 -- gid */
                                *((gid_t *) p) = t;
                        } else {                        /* i == 2 -- uid */
                                *((uid_t *) p) = t;
                        }
                }

                *line++ = '\0';
                i++;
        } /* while (1) */

        return -1;
}

/**********************************************************************/

static const unsigned char gr_off[] ALIGN1 = {
        offsetof(struct group, gr_name),        /* 0 */
        offsetof(struct group, gr_passwd),      /* 1 */
        offsetof(struct group, gr_gid)          /* 2 - not a char ptr */
};

static int FAST_FUNC bb__parsegrent(void *data, char *line)
{
        char *endptr;
        char *p;
        int i;
        char **members;
        char *end_of_buf;

        end_of_buf = ((struct group *) data)->gr_name; /* Evil hack! */
        i = 0;
        while (1) {
                p = (char *) data + gr_off[i];

                if (i < 2) {
                        *((char **) p) = line;
                        line = strchr(line, ':');
                        if (!line) {
                                break;
                        }
                        *line++ = '\0';
                        i++;
                } else {
                        *((gid_t *) p) = strtoul(line, &endptr, 10);

                        /* NOTE: glibc difference - glibc allows omission of the
                         * trailing colon when there is no member list.  We treat
                         * this as an error. */

                        /* Make sure we had at least one digit, and that the
                         * failing char is the next field seperator ':'.  See
                         * glibc difference note above. */
                        if ((endptr == line) || (*endptr != ':')) {
                                break;
                        }

                        i = 1;                          /* Count terminating NULL ptr. */
                        p = endptr;

                        if (p[1]) { /* We have a member list to process. */
                                /* Overwrite the last ':' with a ',' before counting.
                                 * This allows us to (1) test for initial ','
                                 * and (2) adds one ',' so that the number of commas
                                 * equals the member count. */
                                *p = ',';
                                do {
                                        /* NOTE: glibc difference - glibc allows and trims leading
                                         * (but not trailing) space.  We treat this as an error. */
                                        /* NOTE: glibc difference - glibc allows consecutive and
                                         * trailing commas, and ignores "empty string" users.  We
                                         * treat this as an error. */
                                        if (*p == ',') {
                                                ++i;
                                                *p = 0; /* nul-terminate each member string. */
                                                if (!*++p || (*p == ',') || isspace(*p)) {
                                                        goto ERR;
                                                }
                                        }
                                } while (*++p);
                        }

                        /* Now align (p+1), rounding up. */
                        /* Assumes sizeof(char **) is a power of 2. */
                        members = (char **)( (((intptr_t) p) + sizeof(char **))
                                                                 & ~((intptr_t)(sizeof(char **) - 1)) );

                        if (((char *)(members + i)) > end_of_buf) {     /* No space. */
                                break;
                        }

                        ((struct group *) data)->gr_mem = members;

                        if (--i) {
                                p = endptr;     /* Pointing to char prior to first member. */
                                while (1) {
                                        *members++ = ++p;
                                        if (!--i)
                                                break;
                                        while (*++p)
                                                continue;
                                }
                        }
                        *members = NULL;

                        return 0;
                }
        } /* while (1) */

 ERR:
        return -1;
}

/**********************************************************************/

#if ENABLE_USE_BB_SHADOW
static const unsigned char sp_off[] ALIGN1 = {
        offsetof(struct spwd, sp_namp),         /* 0: char* */
        offsetof(struct spwd, sp_pwdp),         /* 1: char* */
        offsetof(struct spwd, sp_lstchg),       /* 2: long */
        offsetof(struct spwd, sp_min),          /* 3: long */
        offsetof(struct spwd, sp_max),          /* 4: long */
        offsetof(struct spwd, sp_warn),         /* 5: long */
        offsetof(struct spwd, sp_inact),        /* 6: long */
        offsetof(struct spwd, sp_expire),       /* 7: long */
        offsetof(struct spwd, sp_flag)          /* 8: unsigned long */
};

static int FAST_FUNC bb__parsespent(void *data, char *line)
{
        char *endptr;
        char *p;
        int i;

        i = 0;
        while (1) {
                p = (char *) data + sp_off[i];
                if (i < 2) {
                        *((char **) p) = line;
                        line = strchr(line, ':');
                        if (!line) {
                                break; /* error */
                        }
                } else {
                        *((long *) p) = strtoul(line, &endptr, 10);
                        if (endptr == line) {
                                *((long *) p) = -1L;
                        }
                        line = endptr;
                        if (i == 8) {
                                if (*line != '\0') {
                                        break; /* error */
                                }
                                return 0; /* all ok */
                        }
                        if (*line != ':') {
                                break; /* error */
                        }
                }
                *line++ = '\0';
                i++;
        }

        return EINVAL;
}
#endif

/**********************************************************************/

/* Reads until EOF, or until it finds a line which fits in the buffer
 * and for which the parser function succeeds.
 *
 * Returns 0 on success and ENOENT for end-of-file (glibc convention).
 */
static int bb__pgsreader(
                int FAST_FUNC (*parserfunc)(void *d, char *line),
                void *data,
                char *__restrict line_buff,
                size_t buflen,
                FILE *f)
{
        int skip;
        int rv = ERANGE;

        if (buflen < PWD_BUFFER_SIZE) {
                errno = rv;
                return rv;
        }

        skip = 0;
        while (1) {
                if (!fgets(line_buff, buflen, f)) {
                        if (feof(f)) {
                                rv = ENOENT;
                        }
                        break;
                }

                {
                        int line_len = strlen(line_buff) - 1;
                        if (line_len >= 0 && line_buff[line_len] == '\n') {
                                line_buff[line_len] = '\0';
                        } else
                        if (line_len + 2 == buflen) {
                                /* A start (or continuation) of overlong line */
                                skip = 1;
                                continue;
                        } /* else: a last line in the file, and it has no '\n' */
                }

                if (skip) {
                        /* This "line" is a remainder of overlong line, ignore */
                        skip = 0;
                        continue;
                }

                /* NOTE: glibc difference - glibc strips leading whitespace from
                 * records.  We do not allow leading whitespace. */

                /* Skip empty lines, comment lines, and lines with leading
                 * whitespace. */
                if (line_buff[0] != '\0' && line_buff[0] != '#' && !isspace(line_buff[0])) {
                        if (parserfunc == bb__parsegrent) {
                                /* Do evil group hack:
                                 * The group entry parsing function needs to know where
                                 * the end of the buffer is so that it can construct the
                                 * group member ptr table. */
                                ((struct group *) data)->gr_name = line_buff + buflen;
                        }
                        if (parserfunc(data, line_buff) == 0) {
                                rv = 0;
                                break;
                        }
                }
        } /* while (1) */

        return rv;
}