cosmopolitan/third_party/musl/pwd.c
Justine Tunney 43fe5956ad
Use DNS implementation from Musl Libc
Now that our socket system call polyfills are good enough to support
Musl's DNS library we should be using that rather than the barebones
domain name system implementation we rolled on our own. There's many
benefits to making this change. So many, that I myself wouldn't feel
qualified to enumerate them all. The Musl DNS code had to be changed
in order to support Windows of course, which looks very solid so far
2023-12-28 23:04:35 -08:00

320 lines
8.7 KiB
C

/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
│ vi: set noet ft=c ts=8 sw=8 fenc=utf-8 :vi │
╚──────────────────────────────────────────────────────────────────────────────╝
│ │
│ Musl Libc │
│ Copyright © 2005-2014 Rich Felker, et al. │
│ │
│ Permission is hereby granted, free of charge, to any person obtaining │
│ a copy of this software and associated documentation files (the │
│ "Software"), to deal in the Software without restriction, including │
│ without limitation the rights to use, copy, modify, merge, publish, │
│ distribute, sublicense, and/or sell copies of the Software, and to │
│ permit persons to whom the Software is furnished to do so, subject to │
│ the following conditions: │
│ │
│ The above copyright notice and this permission notice shall be │
│ included in all copies or substantial portions of the Software. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
│ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY │
│ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, │
│ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE │
│ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
│ │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/weirdtypes.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/limits.h"
#include "libc/mem/mem.h"
#include "libc/paths.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/append.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/thread/thread.h"
#include "third_party/musl/passwd.h"
asm(".ident\t\"\\n\\n\
Musl libc (MIT License)\\n\
Copyright 2005-2014 Rich Felker, et. al.\"");
asm(".include \"libc/disclaimer.inc\"");
#ifdef FTRACE
// if the default mode debugging tools are enabled, and we're linking
// something as substantive as this library, then we shall assume the
// application is meaty enough to benefit from the performance of the
// chromium zlib library (costs ~40kb binary) versus just having puff
__static_yoink("_Cz_inflateInit2");
__static_yoink("_Cz_inflate");
__static_yoink("_Cz_inflateEnd");
#endif
static char *
__create_synthetic_passwd_file(void)
{
int uid, gid;
char login[256], cwd[PATH_MAX];
char *user, *home, *shell, *res = 0;
uid = getuid();
gid = getgid();
user = getenv("USER");
home = getenv("HOME");
shell = getenv("SHELL");
if (user && strchr(user, ':'))
user = 0;
if (home && strchr(home, ':'))
user = 0;
if (shell && strchr(shell, ':'))
user = 0;
if (!shell)
shell = _PATH_BSHELL;
if (!user && getlogin_r(login, sizeof(login)) != -1)
user = login;
if (!home && getcwd(cwd, sizeof(cwd))) {
if (!strchr(cwd, ':'))
home = cwd;
else
home = "/";
}
if (uid)
appendf(&res, "root:x:0:0:root:/root:%s\n", shell);
if (user && home) {
appendf(&res, "%s:x:%d:%d:%s:%s:%s\n",
user, uid, gid, user, home, shell);
}
return res;
}
static FILE *
__fopen_passwd(void)
{
FILE *f;
char *s;
// MacOS has a fake /etc/passwd file without any user details.
if (!IsXnu() && (f = fopen("/etc/passwd", "rbe")))
return f;
if (!(s = __create_synthetic_passwd_file()))
return 0;
if (!(f = fmemopen(s, strlen(s), "rbe")))
free(s);
return f;
}
static unsigned
atou(char **s)
{
unsigned x;
for (x = 0; **s - '0' < 10U; ++*s) {
x = 10 * x + (**s - '0');
}
return x;
}
int
__getpwent_a(FILE *f, struct passwd *pw, char **line, size_t *size,
struct passwd **res)
{
ssize_t l;
char *s;
int rv = 0;
int cs;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
for (;;) {
if ((l = getline(line, size, f)) < 0) {
rv = ferror(f) ? errno : 0;
free(*line);
*line = 0;
pw = 0;
break;
}
line[0][l - 1] = 0;
s = line[0];
pw->pw_name = s++;
if (!(s = strchr(s, ':'))) continue;
*s++ = 0;
pw->pw_passwd = s;
if (!(s = strchr(s, ':'))) continue;
*s++ = 0;
pw->pw_uid = atou(&s);
if (*s != ':') continue;
*s++ = 0;
pw->pw_gid = atou(&s);
if (*s != ':') continue;
*s++ = 0;
pw->pw_gecos = s;
if (!(s = strchr(s, ':'))) continue;
*s++ = 0;
pw->pw_dir = s;
if (!(s = strchr(s, ':'))) continue;
*s++ = 0;
pw->pw_shell = s;
break;
}
pthread_setcancelstate(cs, 0);
*res = pw;
if (rv) errno = rv;
return rv;
}
int
__getpw_a(const char *name, uid_t uid, struct passwd *pw, char **buf,
size_t *size, struct passwd **res)
{
FILE *f;
int cs;
int rv = 0;
*res = 0;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
if ((f = __fopen_passwd())) {
while (!(rv = __getpwent_a(f, pw, buf, size, res)) && *res) {
if ((name && !strcmp(name, (*res)->pw_name)) ||
(!name && (*res)->pw_uid == uid)) {
break;
}
}
fclose(f);
}
pthread_setcancelstate(cs, 0);
if (rv) errno = rv;
return rv;
}
static int
getpw_r(const char *name, uid_t uid, struct passwd *pw, char *buf,
size_t size, struct passwd **res)
{
#define FIX(x) (pw->pw_##x = pw->pw_##x - line + buf)
char *line = 0;
size_t len = 0;
int rv = 0;
int cs;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
rv = __getpw_a(name, uid, pw, &line, &len, res);
if (*res && size < len) {
*res = 0;
rv = ERANGE;
}
if (*res) {
memcpy(buf, line, len);
FIX(name);
FIX(passwd);
FIX(gecos);
FIX(dir);
FIX(shell);
}
free(line);
pthread_setcancelstate(cs, 0);
if (rv) errno = rv;
return rv;
#undef FIX
}
int
getpwnam_r(const char *name, struct passwd *pw, char *buf, size_t size,
struct passwd **res)
{
return getpw_r(name, 0, pw, buf, size, res);
}
int
getpwuid_r(uid_t uid, struct passwd *pw, char *buf, size_t size,
struct passwd **res)
{
return getpw_r(0, uid, pw, buf, size, res);
}
static struct GetpwentState {
FILE *f;
char *line;
struct passwd pw;
size_t size;
} g_getpwent;
/**
* Closes global handle to password database.
*
* @see getpwent()
* @threadunsafe
*/
void
endpwent(void)
{
setpwent();
}
/**
* Rewinds global handle to password database.
*
* @see getpwent()
* @threadunsafe
*/
void
setpwent(void)
{
if (g_getpwent.f)
fclose(g_getpwent.f);
g_getpwent.f = 0;
}
/**
* Returns next entry in password database.
*
* @return pointer to entry static memory, or NULL on EOF
* @see setpwent()
* @threadunsafe
*/
struct passwd *
getpwent()
{
struct passwd *res;
if (!g_getpwent.f)
g_getpwent.f = __fopen_passwd();
if (!g_getpwent.f)
return 0;
__getpwent_a(g_getpwent.f, &g_getpwent.pw, &g_getpwent.line,
&g_getpwent.size, &res);
return res;
}
/**
* Returns password database entry for user id.
*
* This is essentially guaranteed to succeed if `uid == getuid()`, since
* this implementation will generate an entry based on the environment
* if `/etc/passwd` doesn't exist, or is fake (e.g. MacOS).
*
* @return pointer to passwd entry static memory, or NULL if not found
* @threadunsafe
*/
struct passwd *
getpwuid(uid_t uid)
{
struct passwd *res;
__getpw_a(0, uid, &g_getpwent.pw, &g_getpwent.line, &g_getpwent.size,
&res);
return res;
}
/**
* Returns password database entry for user name.
*
* This is essentially guaranteed to succeed if `uid == getenv("USER")`,
* since this implementation will generate an entry based on `environ`
* if `/etc/passwd` doesn't exist, or is fake (e.g. MacOS).
*
* @return pointer to passwd entry static memory, or NULL if not found
* @threadunsafe
*/
struct passwd *
getpwnam(const char *name)
{
struct passwd *res;
__getpw_a(name, 0, &g_getpwent.pw, &g_getpwent.line,
&g_getpwent.size, &res);
return res;
}