/* $NetBSD: homedir.c,v 1.3 2015/01/17 17:46:31 christos Exp $ */
/*
* Copyright (c) 1997-2014 Erez Zadok
* Copyright (c) 1989 Jan-Simon Pendry
* Copyright (c) 1989 Imperial College of Science, Technology & Medicine
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry at Imperial College, London.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*
* File: am-utils/hlfsd/homedir.c
*
* HLFSD was written at Columbia University Computer Science Department, by
* Erez Zadok <
[email protected]> and Alexander Dupuy <
[email protected]>
* It is being distributed under the same terms and conditions as amd does.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <am_defs.h>
#include <hlfsd.h>
/*
* STATIC VARIABLES AND FUNCTIONS:
*/
static FILE *passwd_fp = NULL;
static char pw_name[16], pw_dir[128];
static int cur_pwtab_num = 0, max_pwtab_num = 0;
static int hlfsd_diskspace(char *);
static int hlfsd_stat(char *, struct stat *);
static int passwd_line = 0;
static int plt_reset(void);
static struct passwd passwd_ent;
static uid2home_t *lastchild;
static uid2home_t *pwtab;
static void delay(uid2home_t *, int);
static void table_add(u_int, const char *, const char *);
static char mboxfile[MAXPATHLEN];
static char *root_home; /* root's home directory */
/* GLOBAL FUNCTIONS */
char *homeof(char *username);
int uidof(char *username);
/* GLOBALS VARIABLES */
username2uid_t *untab; /* user name table */
/*
* Return the home directory pathname for the user with uid "userid".
*/
char *
homedir(int userid, int groupid)
{
static char linkval[MAXPATHLEN + 1];
static struct timeval tp;
uid2home_t *found;
char *homename;
struct stat homestat;
int old_groupid, old_userid;
if ((found = plt_search(userid)) == (uid2home_t *) NULL) {
return alt_spooldir; /* use alt spool for unknown uid */
}
homename = found->home;
if (homename[0] != '/' || homename[1] == '\0') {
found->last_status = 1;
return alt_spooldir; /* use alt spool for / or rel. home */
}
if ((int) userid == 0) /* force all uid 0 to use root's home */
xsnprintf(linkval, sizeof(linkval), "%s/%s", root_home, home_subdir);
else
xsnprintf(linkval, sizeof(linkval), "%s/%s", homename, home_subdir);
if (noverify) {
found->last_status = 0;
return linkval;
}
/*
* To optimize hlfsd, we don't actually check the validity of the
* symlink if it has been checked in the last N seconds. It is
* very likely that the link, machine, and filesystem are still
* valid, as long as N is small. But if N is large, that may not be
* true. That's why the default N is 5 minutes, but we allow the
* user to override this value via a command line option. Note that
* we do not update the last_access_time each time it is accessed,
* but only once every N seconds.
*/
if (gettimeofday(&tp, (struct timezone *) NULL) < 0) {
tp.tv_sec = 0;
} else {
if ((tp.tv_sec - found->last_access_time) < cache_interval) {
if (found->last_status == 0) {
return linkval;
} else {
return alt_spooldir;
}
} else {
found->last_access_time = tp.tv_sec;
}
}
/*
* Only run this forking code if ask for -D fork (default).
* Disable forking using -D nofork.
*/
if (amuDebug(D_FORK)) {
/* fork child to process request if none in progress */
if (found->child && kill(found->child, 0))
found->child = 0;
if (found->child)
delay(found, 5); /* wait a bit if in progress */
if (found->child) { /* better safe than sorry - maybe */
found->last_status = 1;
return alt_spooldir;
}
if ((found->child = fork()) < 0) {
found->last_status = 1;
return alt_spooldir;
}
if (found->child) { /* PARENT */
if (lastchild)
dlog("cache spill uid = %ld, pid = %ld, home = %s",
(long) lastchild->uid, (long) lastchild->child,
lastchild->home);
lastchild = found;
return (char *) NULL; /* return NULL to parent, so it can continue */
}
}
/*
* CHILD: (or parent if -D fork)
*
* Check and create dir if needed.
* Check disk space and/or quotas too.
*
* We don't need to set the _last_status field of found after the fork
* in the child, b/c that information would be later determined in
* nfsproc_readlink_2() and the correct exit status would be returned
* to the parent upon SIGCHLD in interlock().
*
*/
am_set_mypid(); /* for logging routines */
if ((old_groupid = setgid(groupid)) < 0) {
plog(XLOG_WARNING, "could not setgid to %d: %m", groupid);
return linkval;
}
if ((old_userid = seteuid(userid)) < 0) {
plog(XLOG_WARNING, "could not seteuid to %d: %m", userid);
setgid(old_groupid);
return linkval;
}
if (hlfsd_stat(linkval, &homestat) < 0) {
if (errno == ENOENT) { /* make the spool dir if possible */
/* don't use recursive mkdirs here */
if (mkdir(linkval, PERS_SPOOLMODE) < 0) {
seteuid(old_userid);
setgid(old_groupid);
plog(XLOG_WARNING, "can't make directory %s: %m", linkval);
return alt_spooldir;
}
/* fall through to testing the disk space / quota */
} else { /* the home dir itself must not exist then */
seteuid(old_userid);
setgid(old_groupid);
plog(XLOG_WARNING, "bad link to %s: %m", linkval);
return alt_spooldir;
}
}
/*
* If gets here, then either the spool dir in the home dir exists,
* or it was just created. In either case, we now need to
* test if we can create a small file and write at least one
* byte into it. This will test that we have both enough inodes
* and disk blocks to spare, or they fall within the user's quotas too.
* We are still seteuid to the user at this point.
*/
if (hlfsd_diskspace(linkval) < 0) {
seteuid(old_userid);
setgid(old_groupid);
plog(XLOG_WARNING, "no more space in %s: %m", linkval);
return alt_spooldir;
} else {
seteuid(old_userid);
setgid(old_groupid);
return linkval;
}
}
static int
hlfsd_diskspace(char *path)
{
char buf[MAXPATHLEN];
int fd, len;
xsnprintf(buf, sizeof(buf), "%s/._hlfstmp_%lu", path, (long) getpid());
if ((fd = open(buf, O_RDWR | O_CREAT, 0600)) < 0) {
plog(XLOG_ERROR, "cannot open %s: %m", buf);
return -1;
}
len = strlen(buf);
if (write(fd, buf, len) < len) {
plog(XLOG_ERROR, "cannot write \"%s\" (%d bytes) to %s : %m", buf, len, buf);
close(fd);
unlink(buf); /* cleanup just in case */
return -1;
}
if (unlink(buf) < 0) {
plog(XLOG_ERROR, "cannot unlink %s : %m", buf);
}
close(fd);
return 0;
}
static int
hlfsd_stat(char *path, struct stat *statp)
{
if (stat(path, statp) < 0)
return -1;
else if (!S_ISDIR(statp->st_mode)) {
errno = ENOTDIR;
return -1;
}
return 0;
}
static void
delay(uid2home_t *found, int secs)
{
struct timeval tv;
if (found)
dlog("delaying on child %ld for %d seconds", (long) found->child, secs);
tv.tv_usec = 0;
do {
tv.tv_sec = secs;
if (select(0, NULL, NULL, NULL, &tv) == 0)
break;
} while (--secs && found->child);
}
/*
* This function is called when a child has terminated after
* servicing an nfs request. We need to check the exit status and
* update the last_status field of the requesting user.
*/
RETSIGTYPE
interlock(int signum)
{
int child;
uid2home_t *lostchild;
int status;
#ifdef HAVE_WAITPID
while ((child = waitpid((pid_t) -1, &status, WNOHANG)) > 0) {
#else /* not HAVE_WAITPID */
while ((child = wait3(&status, WNOHANG, (struct rusage *) NULL)) > 0) {
#endif /* not HAVE_WAITPID */
/* high chances this was the last child forked */
if (lastchild && lastchild->child == child) {
lastchild->child = 0;
if (WIFEXITED(status))
lastchild->last_status = WEXITSTATUS(status);
lastchild = (uid2home_t *) NULL;
} else {
/* and if not, we have to search for it... */
for (lostchild = pwtab; lostchild < &pwtab[cur_pwtab_num]; lostchild++) {
if (lostchild->child == child) {
if (WIFEXITED(status))
lostchild->last_status = WEXITSTATUS(status);
lostchild->child = 0;
break;
}
}
}
}
}
/*
* PASSWORD AND USERNAME LOOKUP TABLES FUNCTIONS
*/
/*
* get index of UserName table entry which matches username.
* must not return uid_t because we want to return a negative number.
*/
int
untab_index(char *username)
{
int max, min, mid, cmp;
max = cur_pwtab_num - 1;
min = 0;
do {
mid = (max + min) / 2;
cmp = strcmp(untab[mid].username, username);
if (cmp == 0) /* record found! */
return mid;
if (cmp > 0)
max = mid;
else
min = mid;
} while (max > min + 1);
if (STREQ(untab[max].username, username))
return max;
if (STREQ(untab[min].username, username))
return min;
/* if gets here then record was not found */
return -1;
}
/*
* Don't make this return a uid_t, because we need to return negative
* numbers as well (error codes.)
*/
int
uidof(char *username)
{
int idx;
if ((idx = untab_index(username)) < 0) /* not found */
return INVALIDID; /* an invalid user id */
return untab[idx].uid;
}
/*
* Don't make this return a uid_t, because we need to return negative
* numbers as well (error codes.)
*/
char *
homeof(char *username)
{
int idx;
if ((idx = untab_index(username)) < 0) /* not found */
return (char *) NULL; /* an invalid user id */
return untab[idx].home;
}
char *
mailbox(int uid, char *username)
{
char *home;
if (uid < 0)
return (char *) NULL; /* not found */
if ((home = homeof(username)) == (char *) NULL)
return (char *) NULL;
if (STREQ(home, "/"))
xsnprintf(mboxfile, sizeof(mboxfile),
"/%s/%s", home_subdir, username);
else
xsnprintf(mboxfile, sizeof(mboxfile),
"%s/%s/%s", home, home_subdir, username);
return mboxfile;
}
static int
plt_compare_fxn(const voidp x, const voidp y)
{
uid2home_t *i = (uid2home_t *) x;
uid2home_t *j = (uid2home_t *) y;
return i->uid - j->uid;
}
static int
unt_compare_fxn(const voidp x, const voidp y)
{
username2uid_t *i = (username2uid_t *) x;
username2uid_t *j = (username2uid_t *) y;
return strcmp(i->username, j->username);
}
/* perform initialization of user passwd database */
static void
hlfsd_setpwent(void)
{
if (!passwdfile) {
setpwent();
return;
}
passwd_fp = fopen(passwdfile, "r");
if (!passwd_fp) {
plog(XLOG_ERROR, "unable to read passwd file %s: %m", passwdfile);
return;
}
plog(XLOG_INFO, "reading password entries from file %s", passwdfile);
passwd_line = 0;
memset((char *) &passwd_ent, 0, sizeof(struct passwd));
passwd_ent.pw_name = (char *) &pw_name;
passwd_ent.pw_dir = (char *) &pw_dir;
}
/* perform de-initialization of user passwd database */
static void
hlfsd_endpwent(void)
{
if (!passwdfile) {
/*
* Don't actually run this because we will be making more passwd calls
* afterwards. On Solaris 2.5.1, making getpwent() calls after calling
* endpwent() results in a memory leak! (and no, even Purify didn't
* detect it...)
*
endpwent();
*/
return;
}
if (passwd_fp) {
fclose(passwd_fp);
}
}
/* perform record reading/parsing of individual passwd database records */
static struct passwd *
hlfsd_getpwent(void)
{
char buf[256], *cp;
/* check if to perform standard unix function */
if (!passwdfile) {
return getpwent();
}
/* return here to read another entry */
readent:
/* return NULL if reached end of file */
if (feof(passwd_fp))
return NULL;
pw_name[0] = pw_dir[0] = '\0';
/* read records */
buf[0] = '\0';
if (fgets(buf, 256, passwd_fp) == NULL)
return NULL;
passwd_line++;
if (buf[0] == '\0')
goto readent;
/* read user name */
cp = strtok(buf, ":");
if (!cp || cp[0] == '\0') {
plog(XLOG_ERROR, "no user name on line %d of %s", passwd_line, passwdfile);
goto readent;
}
/* pw_name will show up in passwd_ent.pw_name */
xstrlcpy(pw_name, cp, sizeof(pw_name));
/* skip passwd */
strtok(NULL, ":");
/* read uid */
cp = strtok(NULL, ":");
if (!cp || cp[0] == '\0') {
plog(XLOG_ERROR, "no uid on line %d of %s", passwd_line, passwdfile);
goto readent;
}
passwd_ent.pw_uid = atoi(cp);
/* skip gid and gcos */
strtok(NULL, ":");
strtok(NULL, ":");
/* read home dir */
cp = strtok(NULL, ":");
if (!cp || cp[0] == '\0') {
plog(XLOG_ERROR, "no home dir on line %d of %s", passwd_line, passwdfile);
goto readent;
}
/* pw_dir will show up in passwd_ent.pw_dir */
xstrlcpy(pw_dir, cp, sizeof(pw_dir));
/* the rest of the fields are unimportant and not being considered */
plog(XLOG_USER, "hlfsd_getpwent: name=%s, uid=%ld, dir=%s",
passwd_ent.pw_name, (long) passwd_ent.pw_uid, passwd_ent.pw_dir);
return &passwd_ent;
}
/*
* read and hash the passwd file or NIS map
*/
void
plt_init(void)
{
struct passwd *pent_p;
if (plt_reset() < 0) /* could not reset table. skip. */
return;
plog(XLOG_INFO, "reading password map");
hlfsd_setpwent(); /* prepare to read passwd entries */
while ((pent_p = hlfsd_getpwent()) != (struct passwd *) NULL) {
table_add(pent_p->pw_uid, pent_p->pw_dir, pent_p->pw_name);
if (STREQ("root", pent_p->pw_name)) {
int len;
if (root_home)
XFREE(root_home);
root_home = xstrdup(pent_p->pw_dir);
len = strlen(root_home);
/* remove any trailing '/' chars from root's home (even if just one) */
while (len > 0 && root_home[len - 1] == '/') {
len--;
root_home[len] = '\0';
}
}
}
hlfsd_endpwent();
qsort((char *) pwtab, cur_pwtab_num, sizeof(uid2home_t),
plt_compare_fxn);
qsort((char *) untab, cur_pwtab_num, sizeof(username2uid_t),
unt_compare_fxn);
if (!root_home)
root_home = xstrdup("");
plog(XLOG_INFO, "password map read and sorted");
}
/*
* This is essentially so that we don't reset known good lookup tables when a
* YP server goes down.
*/
static int
plt_reset(void)
{
int i;
hlfsd_setpwent();
if (hlfsd_getpwent() == (struct passwd *) NULL) {
hlfsd_endpwent();
return -1; /* did not reset table */
}
hlfsd_endpwent();
lastchild = (uid2home_t *) NULL;
if (max_pwtab_num > 0) /* was used already. cleanup old table */
for (i = 0; i < cur_pwtab_num; ++i) {
if (pwtab[i].home) {
XFREE(pwtab[i].home);
pwtab[i].home = (char *) NULL;
}
pwtab[i].uid = INVALIDID; /* not a valid uid (yet...) */
pwtab[i].child = (pid_t) 0;
pwtab[i].uname = (char *) NULL; /* only a ptr to untab[i].username */
if (untab[i].username) {
XFREE(untab[i].username);
untab[i].username = (char *) NULL;
}
untab[i].uid = INVALIDID; /* invalid uid */
untab[i].home = (char *) NULL; /* only a ptr to pwtab[i].home */
}
cur_pwtab_num = 0; /* zero current size */
if (root_home)
XFREE(root_home);
return 0; /* resetting ok */
}
/*
* u: uid number
* h: home directory
* n: user ID name
*/
static void
table_add(u_int u, const char *h, const char *n)
{
int i;
if (max_pwtab_num <= 0) { /* was never initialized */
max_pwtab_num = 1;
pwtab = (uid2home_t *) xmalloc(max_pwtab_num *
sizeof(uid2home_t));
memset((char *) &pwtab[0], 0, max_pwtab_num * sizeof(uid2home_t));
untab = (username2uid_t *) xmalloc(max_pwtab_num *
sizeof(username2uid_t));
memset((char *) &untab[0], 0, max_pwtab_num * sizeof(username2uid_t));
}
/* check if need more space. */
if (cur_pwtab_num + 1 > max_pwtab_num) {
/* need more space in table */
max_pwtab_num *= 2;
plog(XLOG_INFO, "reallocating table spaces to %d entries", max_pwtab_num);
pwtab = (uid2home_t *) xrealloc(pwtab,
sizeof(uid2home_t) * max_pwtab_num);
untab = (username2uid_t *) xrealloc(untab,
sizeof(username2uid_t) *
max_pwtab_num);
/* zero out newly added entries */
for (i=cur_pwtab_num; i<max_pwtab_num; ++i) {
memset((char *) &pwtab[i], 0, sizeof(uid2home_t));
memset((char *) &untab[i], 0, sizeof(username2uid_t));
}
}
/* do NOT add duplicate entries (this is an O(N^2) algorithm... */
for (i=0; i<cur_pwtab_num; ++i)
if (u == pwtab[i].uid && u != 0 ) {
dlog("ignoring duplicate home %s for uid %d (already %s)",
h, u, pwtab[i].home);
return;
}
/* add new password entry */
pwtab[cur_pwtab_num].home = xstrdup(h);
pwtab[cur_pwtab_num].child = 0;
pwtab[cur_pwtab_num].last_access_time = 0;
pwtab[cur_pwtab_num].last_status = 0; /* assume best: used homedir */
pwtab[cur_pwtab_num].uid = u;
/* add new userhome entry */
untab[cur_pwtab_num].username = xstrdup(n);
/* just a second pointer */
pwtab[cur_pwtab_num].uname = untab[cur_pwtab_num].username;
untab[cur_pwtab_num].uid = u;
untab[cur_pwtab_num].home = pwtab[cur_pwtab_num].home; /* a ptr */
/* increment counter */
++cur_pwtab_num;
}
/*
* return entry in lookup table
*/
uid2home_t *
plt_search(u_int u)
{
int max, min, mid;
/*
* empty table should not happen,
* but I have a bug with signals to trace...
*/
if (pwtab == (uid2home_t *) NULL)
return (uid2home_t *) NULL;
max = cur_pwtab_num - 1;
min = 0;
do {
mid = (max + min) / 2;
if (pwtab[mid].uid == u) /* record found! */
return &pwtab[mid];
if (pwtab[mid].uid > u)
max = mid;
else
min = mid;
} while (max > min + 1);
if (pwtab[max].uid == u)
return &pwtab[max];
if (pwtab[min].uid == u)
return &pwtab[min];
/* if gets here then record was not found */
return (uid2home_t *) NULL;
}
#if defined(DEBUG) || defined(DEBUG_PRINT)
void
plt_print(int signum)
{
FILE *dumpfile;
int dumpfd;
char dumptmp[] = "/usr/tmp/hlfsd.dump.XXXXXX";
int i;
#ifdef HAVE_MKSTEMP
dumpfd = mkstemp(dumptmp);
#else /* not HAVE_MKSTEMP */
mktemp(dumptmp);
if (!dumptmp) {
plog(XLOG_ERROR, "cannot create temporary dump file");
return;
}
dumpfd = open(dumptmp, O_RDONLY);
#endif /* not HAVE_MKSTEMP */
if (dumpfd < 0) {
plog(XLOG_ERROR, "cannot open temporary dump file");
return;
}
if ((dumpfile = fdopen(dumpfd, "a")) != NULL) {
plog(XLOG_INFO, "dumping internal state to file %s", dumptmp);
fprintf(dumpfile, "\n\nNew plt_dump():\n");
for (i = 0; i < cur_pwtab_num; ++i)
fprintf(dumpfile,
"%4d %5lu %10lu %1d %4lu \"%s\" uname=\"%s\"\n",
i,
(long) pwtab[i].child,
pwtab[i].last_access_time,
pwtab[i].last_status,
(long) pwtab[i].uid,
pwtab[i].home,
pwtab[i].uname);
fprintf(dumpfile, "\nUserName table by plt_print():\n");
for (i = 0; i < cur_pwtab_num; ++i)
fprintf(dumpfile, "%4d : \"%s\" %4lu \"%s\"\n", i,
untab[i].username, (long) untab[i].uid, untab[i].home);
close(dumpfd);
fclose(dumpfile);
}
}
void
plt_dump(uid2home_t *lastc, pid_t this)
{
FILE *dumpfile;
int i;
if ((dumpfile = fopen("/var/tmp/hlfsdump", "a")) != NULL) {
fprintf(dumpfile, "\n\nNEW PLT_DUMP -- ");
fprintf(dumpfile, "lastchild->child=%d ",
(int) (lastc ? lastc->child : -999));
fprintf(dumpfile, ", child from wait3=%lu:\n", (long) this);
for (i = 0; i < cur_pwtab_num; ++i)
fprintf(dumpfile, "%4d %5lu: %4lu \"%s\" uname=\"%s\"\n", i,
(long) pwtab[i].child, (long) pwtab[i].uid,
pwtab[i].home, pwtab[i].uname);
fprintf(dumpfile, "\nUserName table by plt_dump():\n");
for (i = 0; i < cur_pwtab_num; ++i)
fprintf(dumpfile, "%4d : \"%s\" %4lu \"%s\"\n", i,
untab[i].username, (long) untab[i].uid, untab[i].home);
fprintf(dumpfile, "ezk: ent=%d, uid=%lu, home=\"%s\"\n",
untab_index("ezk"),
(long) untab[untab_index("ezk")].uid,
pwtab[untab[untab_index("ezk")].uid].home);
fprintf(dumpfile, "rezk: ent=%d, uid=%lu, home=\"%s\"\n",
untab_index("rezk"),
(long) untab[untab_index("rezk")].uid,
pwtab[untab[untab_index("rezk")].uid].home);
fclose(dumpfile);
}
}
#endif /* defined(DEBUG) || defined(DEBUG_PRINT) */
