newlib-cygwin/winsup/cygwin/passwd.cc

447 lines
10 KiB
C++

/* passwd.cc: getpwnam () and friends
Copyright 1996, 1997, 1998 Cygnus Solutions.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include <stdlib.h>
#include <pwd.h>
#include <stdio.h>
#include <errno.h>
#include "cygerrno.h"
#include "security.h"
#include "fhandler.h"
#include "dtable.h"
#include "path.h"
#include "sync.h"
#include "sigproc.h"
#include "pinfo.h"
#include "cygheap.h"
#include <sys/termios.h>
/* Read /etc/passwd only once for better performance. This is done
on the first call that needs information from it. */
static struct passwd *passwd_buf = NULL; /* passwd contents in memory */
static int curr_lines = 0;
static int max_lines = 0;
/* Set to loaded when /etc/passwd has been read in by read_etc_passwd ().
Set to emulated if passwd is emulated. */
/* Functions in this file need to check the value of passwd_state
and read in the password file if it isn't set. */
enum pwd_state {
uninitialized = 0,
initializing,
emulated,
loaded
};
class pwd_check {
pwd_state state;
FILETIME last_modified;
char pwd_w32[MAX_PATH];
public:
pwd_check () : state (uninitialized)
{
last_modified.dwLowDateTime = last_modified.dwHighDateTime = 0;
pwd_w32[0] = '\0';
}
operator pwd_state ()
{
HANDLE h;
WIN32_FIND_DATA data;
if (!pwd_w32[0]) /* First call. */
{
path_conv p ("/etc/passwd", PC_SYM_FOLLOW | PC_FULL);
if (!p.error)
strcpy (pwd_w32, p.get_win32 ());
}
if ((h = FindFirstFile (pwd_w32, &data)) != INVALID_HANDLE_VALUE)
{
if (CompareFileTime (&data.ftLastWriteTime, &last_modified) > 0)
{
state = uninitialized;
last_modified = data.ftLastWriteTime;
}
FindClose (h);
}
return state;
}
void operator = (pwd_state nstate)
{
state = nstate;
}
};
static pwd_check passwd_state;
/* Position in the passwd cache */
#ifdef _MT_SAFE
#define pw_pos _reent_winsup ()->_pw_pos
#else
static int pw_pos = 0;
#endif
/* Remove a : teminated string from the buffer, and increment the pointer */
static char *
grab_string (char **p)
{
char *src = *p;
char *res = src;
while (*src && *src != ':' && *src != '\n')
src++;
if (*src == ':')
{
*src = 0;
src++;
}
*p = src;
return res;
}
/* same, for ints */
static int
grab_int (char **p)
{
char *src = *p;
int val = strtol (src, NULL, 10);
while (*src && *src != ':' && *src != '\n')
src++;
if (*src == ':')
src++;
*p = src;
return val;
}
/* Parse /etc/passwd line into passwd structure. */
void
parse_pwd (struct passwd &res, char *buf)
{
/* Allocate enough room for the passwd struct and all the strings
in it in one go */
size_t len = strlen (buf);
char *mybuf = (char *) malloc (len + 1);
(void) memcpy (mybuf, buf, len + 1);
if (mybuf[--len] == '\n')
mybuf[len] = '\0';
res.pw_name = grab_string (&mybuf);
res.pw_passwd = grab_string (&mybuf);
res.pw_uid = grab_int (&mybuf);
res.pw_gid = grab_int (&mybuf);
res.pw_comment = 0;
res.pw_gecos = grab_string (&mybuf);
res.pw_dir = grab_string (&mybuf);
res.pw_shell = grab_string (&mybuf);
}
/* Add one line from /etc/passwd into the password cache */
static void
add_pwd_line (char *line)
{
if (curr_lines >= max_lines)
{
max_lines += 10;
passwd_buf = (struct passwd *) realloc (passwd_buf, max_lines * sizeof (struct passwd));
}
parse_pwd (passwd_buf[curr_lines++], line);
}
/* Read in /etc/passwd and save contents in the password cache.
This sets passwd_state to loaded or emulated so functions in this file can
tell that /etc/passwd has been read in or will be emulated. */
void
read_etc_passwd ()
{
char linebuf[1024];
/* A mutex is ok for speed here - pthreads will use critical sections not mutex's
* for non-shared mutexs in the future. Also, this function will at most be called
* once from each thread, after that the passwd_state test will succeed
*/
static NO_COPY pthread_mutex_t etc_passwd_mutex = (pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER;
pthread_mutex_lock (&etc_passwd_mutex);
/* if we got blocked by the mutex, then etc_passwd may have been processed */
if (passwd_state != uninitialized)
{
pthread_mutex_unlock(&etc_passwd_mutex);
return;
}
if (passwd_state != initializing)
{
passwd_state = initializing;
if (max_lines) /* When rereading, free allocated memory first. */
{
for (int i = 0; i < curr_lines; ++i)
free (passwd_buf[i].pw_name);
free (passwd_buf);
curr_lines = max_lines = 0;
}
FILE *f = fopen ("/etc/passwd", "rt");
if (f)
{
while (fgets (linebuf, sizeof (linebuf), f) != NULL)
{
if (strlen (linebuf))
add_pwd_line (linebuf);
}
fclose (f);
passwd_state = loaded;
}
else
{
debug_printf ("Emulating /etc/passwd");
snprintf (linebuf, sizeof (linebuf), "%s::%u:%u::%s:/bin/sh", cygheap->user.name (),
DEFAULT_UID, DEFAULT_GID, getenv ("HOME") ?: "/");
add_pwd_line (linebuf);
passwd_state = emulated;
}
}
pthread_mutex_unlock (&etc_passwd_mutex);
}
/* Cygwin internal */
/* If this ever becomes non-reentrant, update all the getpw*_r functions */
static struct passwd *
search_for (uid_t uid, const char *name)
{
struct passwd *res = 0;
struct passwd *default_pw = 0;
for (int i = 0; i < curr_lines; i++)
{
res = passwd_buf + i;
if (res->pw_uid == DEFAULT_UID)
default_pw = res;
/* on Windows NT user names are case-insensitive */
if (name)
{
if (strcasematch (name, res->pw_name))
return res;
}
else if (uid == res->pw_uid)
return res;
}
/* Return default passwd entry if passwd is emulated or it's a
request for the current user. */
if (passwd_state != loaded
|| (!name && uid == myself->uid)
|| (name && strcasematch (name, cygheap->user.name ())))
return default_pw;
return NULL;
}
extern "C" struct passwd *
getpwuid (uid_t uid)
{
if (passwd_state <= initializing)
read_etc_passwd ();
pthread_testcancel();
return search_for (uid, 0);
}
extern "C" int
getpwuid_r (uid_t uid, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result)
{
*result = NULL;
if (!pwd || !buffer)
return ERANGE;
if (passwd_state <= initializing)
read_etc_passwd ();
pthread_testcancel();
struct passwd *temppw = search_for (uid, 0);
if (!temppw)
return 0;
/* check needed buffer size. */
size_t needsize = strlen (temppw->pw_name) + strlen (temppw->pw_dir) +
strlen (temppw->pw_shell) + strlen (temppw->pw_gecos) +
strlen (temppw->pw_passwd) + 5;
if (needsize > bufsize)
return ERANGE;
/* make a copy of temppw */
*result = pwd;
pwd->pw_uid = temppw->pw_uid;
pwd->pw_gid = temppw->pw_gid;
pwd->pw_name = buffer;
pwd->pw_dir = pwd->pw_name + strlen (temppw->pw_name) + 1;
pwd->pw_shell = pwd->pw_dir + strlen (temppw->pw_dir) + 1;
pwd->pw_gecos = pwd->pw_shell + strlen (temppw->pw_shell) + 1;
pwd->pw_passwd = pwd->pw_gecos + strlen (temppw->pw_gecos) + 1;
strcpy (pwd->pw_name, temppw->pw_name);
strcpy (pwd->pw_dir, temppw->pw_dir);
strcpy (pwd->pw_shell, temppw->pw_shell);
strcpy (pwd->pw_gecos, temppw->pw_gecos);
strcpy (pwd->pw_passwd, temppw->pw_passwd);
return 0;
}
extern "C" struct passwd *
getpwnam (const char *name)
{
if (passwd_state <= initializing)
read_etc_passwd ();
pthread_testcancel();
return search_for (0, name);
}
/* the max size buffer we can expect to
* use is returned via sysconf with _SC_GETPW_R_SIZE_MAX.
* This may need updating! - Rob Collins April 2001.
*/
extern "C" int
getpwnam_r (const char *nam, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result)
{
*result = NULL;
if (!pwd || !buffer || !nam)
return ERANGE;
if (passwd_state <= initializing)
read_etc_passwd ();
pthread_testcancel();
struct passwd *temppw = search_for (0, nam);
if (!temppw)
return 0;
/* check needed buffer size. */
size_t needsize = strlen (temppw->pw_name) + strlen (temppw->pw_dir) +
strlen (temppw->pw_shell) + strlen (temppw->pw_gecos) +
strlen (temppw->pw_passwd) + 5;
if (needsize > bufsize)
return ERANGE;
/* make a copy of temppw */
*result = pwd;
pwd->pw_uid = temppw->pw_uid;
pwd->pw_gid = temppw->pw_gid;
pwd->pw_name = buffer;
pwd->pw_dir = pwd->pw_name + strlen (temppw->pw_name) + 1;
pwd->pw_shell = pwd->pw_dir + strlen (temppw->pw_dir) + 1;
pwd->pw_gecos = pwd->pw_shell + strlen (temppw->pw_shell) + 1;
pwd->pw_passwd = pwd->pw_gecos + strlen (temppw->pw_gecos) + 1;
strcpy (pwd->pw_name, temppw->pw_name);
strcpy (pwd->pw_dir, temppw->pw_dir);
strcpy (pwd->pw_shell, temppw->pw_shell);
strcpy (pwd->pw_gecos, temppw->pw_gecos);
strcpy (pwd->pw_passwd, temppw->pw_passwd);
return 0;
}
extern "C" struct passwd *
getpwent (void)
{
if (passwd_state <= initializing)
read_etc_passwd ();
if (pw_pos < curr_lines)
return passwd_buf + pw_pos++;
return NULL;
}
extern "C" struct passwd *
getpwduid (uid_t)
{
return NULL;
}
extern "C" void
setpwent (void)
{
pw_pos = 0;
}
extern "C" void
endpwent (void)
{
pw_pos = 0;
}
extern "C" int
setpassent ()
{
return 0;
}
/* Internal function. ONLY USE THIS INTERNALLY, NEVER `getpwent'!!! */
struct passwd *
internal_getpwent (int pos)
{
if (passwd_state <= initializing)
read_etc_passwd ();
if (pos < curr_lines)
return passwd_buf + pos;
return NULL;
}
extern "C" char *
getpass (const char * prompt)
{
#ifdef _MT_SAFE
char *pass=_reent_winsup ()->_pass;
#else
static char pass[_PASSWORD_LEN];
#endif
struct termios ti, newti;
if (passwd_state <= initializing)
read_etc_passwd ();
if (cygheap->fdtab.not_open (0))
{
set_errno (EBADF);
pass[0] = '\0';
}
else
{
fhandler_base *fhstdin = cygheap->fdtab[0];
fhstdin->tcgetattr (&ti);
newti = ti;
newti.c_lflag &= ~ECHO;
fhstdin->tcsetattr (TCSANOW, &newti);
fputs (prompt, stderr);
fgets (pass, _PASSWORD_LEN, stdin);
fprintf (stderr, "\n");
for (int i=0; pass[i]; i++)
if (pass[i] == '\r' || pass[i] == '\n')
pass[i] = '\0';
fhstdin->tcsetattr (TCSANOW, &ti);
}
return pass;
}