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Libc: single-user getpwent implementation 

Implement the passwd database subroutines with single-user database.
This database is populated with a <passwd/> sub-node of the libc
configuration node. All fields of the "passwd" struct may be specified
with reasonable defaults provided for a "root" user. This allows a
libc-based component to spoof user information for the sake of porting
existing Unix software.

A test is provided at run/libc_getpwent.

Fix #2919
This commit is contained in:
Ehmry - 2018-07-16 16:58:23 +02:00 committed by Christian Helmuth
parent 9f6838ae42
commit 874ba409ca
7 changed files with 402 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
repos/libports/lib/mk/libc.mk
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@ -16,7 +16,8 @@ SRC_CC = atexit.cc dummies.cc rlimit.cc sysctl.cc \
plugin.cc plugin_registry.cc select.cc exit.cc environ.cc nanosleep.cc \
pread_pwrite.cc readv_writev.cc poll.cc \
libc_pdbg.cc vfs_plugin.cc rtc.cc dynamic_linker.cc signal.cc \
socket_operations.cc task.cc socket_fs_plugin.cc syscall.cc
socket_operations.cc task.cc socket_fs_plugin.cc syscall.cc \
getpwent.cc
CC_OPT_sysctl += -Wno-write-strings

2
repos/libports/lib/symbols/libc
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@ -278,7 +278,9 @@ getprogname W
getprotobyname T
getprotobyname_r T
getpwent W
getpwent_r W
getpwnam W
getpwnam_r W
getpwuid W
getpwuid_r W
getrlimit W

135
repos/libports/run/libc_getpwent.run Normal file
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@ -0,0 +1,135 @@
build "core init app/sequence server/vfs test/libc_getpwent"
create_boot_directory
install_config {
<config>
<parent-provides>
<service name="CPU"/>
<service name="LOG"/>
<service name="PD"/>
<service name="RM"/>
<service name="ROM"/>
</parent-provides>
<default-route>
<any-service> <parent/> <any-child/> </any-service>
</default-route>
<default caps="128"/>
<start name="fs">
<binary name="vfs"/>
<resource name="RAM" quantum="4M"/>
<provides> <service name="File_system"/> </provides>
<config>
<vfs> <log label="log"/> </vfs>
<default-policy root="/" writeable="yes"/>
</config>
</start>
<start name="test">
<binary name="sequence"/>
<resource name="RAM" quantum="4M"/>
<config>
<start name="root">
<binary name="test-libc_getpwent"/>
<config>
<vfs> <fs/> </vfs>
<libc stdout="/log" stderr="/log"/>
<arg value="test-libc_getpwent"/>
<env key="HOME" value="/home-from-getenv"/>
</config>
</start>
<start name="alice">
<binary name="test-libc_getpwent"/>
<config>
<vfs> <fs/> </vfs>
<libc stdout="/log" stderr="/log">
<passwd name="alice" uid="1" home="/home/alice"/>
</libc>
</config>
</start>
<start name="bob">
<binary name="test-libc_getpwent"/>
<config>
<vfs> <fs/> </vfs>
<libc stdout="/log" stderr="/log">
<passwd name="bob" uid="2" home="/root"/>
</libc>
</config>
</start>
</config>
</start>
</config>
}
build_boot_image {
core init vfs sequence test-libc_getpwent
ld.lib.so libc.lib.so vfs.lib.so libm.lib.so posix.lib.so
}
append qemu_args " -nographic "
run_genode_until "child .* exited with exit value 0.*\n" 20
grep_output {\[init -\> fs -\> log\] }
compare_output_to {
[init -> fs -> log] [getpwent] user:root uid:0 home:/
[init -> fs -> log] [getpwent] NULL
[init -> fs -> log] [getpwent] NULL
[init -> fs -> log] [getpwent_r] user:root uid:0 home:/
[init -> fs -> log] [getpwent_r] NULL
[init -> fs -> log] [getpwent_r] NULL
[init -> fs -> log] [getpwnam root] user:root uid:0 home:/
[init -> fs -> log] [getpwnam alice] NULL
[init -> fs -> log] [getpwnam bob] NULL
[init -> fs -> log] [getpwnam_r root] user:root uid:0 home:/
[init -> fs -> log] [getpwnam_r alice] NULL
[init -> fs -> log] [getpwnam_r bob] NULL
[init -> fs -> log] [getpwuid 0] user:root uid:0 home:/
[init -> fs -> log] [getpwuid 1] NULL
[init -> fs -> log] [getpwuid 2] NULL
[init -> fs -> log] [getpwuid_r 0] user:root uid:0 home:/
[init -> fs -> log] [getpwuid_r 1] NULL
[init -> fs -> log] [getpwuid_r 2] NULL
[init -> fs -> log] [getpwent] user:alice uid:1 home:/home/alice
[init -> fs -> log] [getpwent] NULL
[init -> fs -> log] [getpwent] NULL
[init -> fs -> log] [getpwent_r] user:alice uid:1 home:/home/alice
[init -> fs -> log] [getpwent_r] NULL
[init -> fs -> log] [getpwent_r] NULL
[init -> fs -> log] [getpwnam root] NULL
[init -> fs -> log] [getpwnam alice] user:alice uid:1 home:/home/alice
[init -> fs -> log] [getpwnam bob] NULL
[init -> fs -> log] [getpwnam_r root] NULL
[init -> fs -> log] [getpwnam_r alice] user:alice uid:1 home:/home/alice
[init -> fs -> log] [getpwnam_r bob] NULL
[init -> fs -> log] [getpwuid 0] NULL
[init -> fs -> log] [getpwuid 1] user:alice uid:1 home:/home/alice
[init -> fs -> log] [getpwuid 2] NULL
[init -> fs -> log] [getpwuid_r 0] NULL
[init -> fs -> log] [getpwuid_r 1] user:alice uid:1 home:/home/alice
[init -> fs -> log] [getpwuid_r 2] NULL
[init -> fs -> log] [getpwent] user:bob uid:2 home:/root
[init -> fs -> log] [getpwent] NULL
[init -> fs -> log] [getpwent] NULL
[init -> fs -> log] [getpwent_r] user:bob uid:2 home:/root
[init -> fs -> log] [getpwent_r] NULL
[init -> fs -> log] [getpwent_r] NULL
[init -> fs -> log] [getpwnam root] NULL
[init -> fs -> log] [getpwnam alice] NULL
[init -> fs -> log] [getpwnam bob] user:bob uid:2 home:/root
[init -> fs -> log] [getpwnam_r root] NULL
[init -> fs -> log] [getpwnam_r alice] NULL
[init -> fs -> log] [getpwnam_r bob] user:bob uid:2 home:/root
[init -> fs -> log] [getpwuid 0] NULL
[init -> fs -> log] [getpwuid 1] NULL
[init -> fs -> log] [getpwuid 2] user:bob uid:2 home:/root
[init -> fs -> log] [getpwuid_r 0] NULL
[init -> fs -> log] [getpwuid_r 1] NULL
[init -> fs -> log] [getpwuid_r 2] user:bob uid:2 home:/root
}

7
repos/libports/src/lib/libc/dummies.cc
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@ -57,7 +57,6 @@ DUMMY(int , -1, chroot, (const char *))
DUMMY(char *, 0, crypt, (const char *, const char *))
DUMMY(DB * , 0, dbopen, (const char *, int, int, DBTYPE, const void *))
DUMMY(u_int32_t, 0, __default_hash, (const void *, size_t));
DUMMY(void , , endpwent, (void))
DUMMY(int , 0, fchmod, (int, mode_t))
DUMMY(int , -1, fchown, (int, uid_t, gid_t))
DUMMY(int , -1, flock, (int, int))
@ -81,10 +80,6 @@ DUMMY(int , -1, getsid, (pid_t))
DUMMY(pid_t , -1, getppid, (void))
DUMMY(pid_t , -1, getpgrp, (void))
DUMMY(int , -1, getpriority, (int, int))
DUMMY(struct passwd *, 0, getpwent, (void))
DUMMY(struct passwd *, 0, getpwnam, (const char *))
DUMMY(struct passwd *, 0, getpwuid, (uid_t))
DUMMY(int , 0, getpwuid_r, (uid_t, struct passwd *, char *, size_t, struct passwd **))
DUMMY(int , -1, getrusage, (int, rusage *))
DUMMY(uid_t , 0, getuid, (void))
DUMMY(int , -1, kill, (pid_t, int))
@ -110,10 +105,8 @@ DUMMY(int , -1, setgid, (gid_t))
DUMMY(int , -1, setuid, (uid_t))
DUMMY(int , -1, setgroups, (int, const gid_t *))
DUMMY(int , -1, setitimer, (int, const itimerval *, itimerval *))
DUMMY(int , -1, setpassent, (int))
DUMMY(int , -1, setpgid, (pid_t, pid_t))
DUMMY(int , -1, setpriority, (int, int, int))
DUMMY(void , , setpwent, (void))
DUMMY(int , -1, setregid, (gid_t, gid_t))
DUMMY(int , -1, setreuid, (uid_t, uid_t))
DUMMY(int , -1, setrlimit, (int, const rlimit *))

184
repos/libports/src/lib/libc/getpwent.cc Normal file
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@ -0,0 +1,184 @@
/*
* \brief Password database operations
* \author Emery Hemingway
* \date 2018-07-15
*/
/*
* Copyright (C) 2018 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
/* Genode includes */
#include <base/log.h>
#include <util/string.h>
/* Libc includes */
#include <sys/types.h>
#include <pwd.h>
#include <stdlib.h>
/* local includes */
#include "libc_errno.h"
#include "task.h"
typedef Genode::String<128> Passwd_string;
struct Passwd_fields {
Passwd_string name { "root" };
Passwd_string passwd { };
unsigned long uid = 0;
unsigned long gid = 0;
unsigned long change = 0;
Passwd_string clas { };
Passwd_string gecos { };
Passwd_string home { "/" };
Passwd_string shell { };
unsigned long expire = 0;
unsigned long fields = 0;
Passwd_fields() { }
};
static void _fill_passwd(struct passwd &db, Passwd_fields &fields)
{
using namespace Genode;
/* reset buffers */
Genode::memset(&db, 0x00, sizeof(struct passwd));
fields = Passwd_fields();
try {
Xml_node const passwd = Libc::libc_config().sub_node("passwd");
fields.name = passwd.attribute_value("name", fields.name);
fields.uid = passwd.attribute_value("uid", 0UL);
fields.gid = passwd.attribute_value("gid", 0UL);
fields.change = passwd.attribute_value("change", 0UL);
fields.passwd = passwd.attribute_value("passwd", fields.passwd);
fields.clas = passwd.attribute_value("class", fields.clas);
fields.gecos = passwd.attribute_value("gecos", fields.gecos);
fields.home = passwd.attribute_value("home", fields.home);
fields.shell = passwd.attribute_value("shell", fields.shell);
fields.expire = passwd.attribute_value("expire", 0UL);
fields.fields = passwd.attribute_value("fields", 0UL);
}
catch (...) { }
db.pw_name = (char *)fields.name.string();
db.pw_uid = fields.uid;
db.pw_gid = fields.gid;
db.pw_change = fields.change;
db.pw_passwd = (char *)fields.passwd.string();
db.pw_class = (char *)fields.clas.string();
db.pw_gecos = (char *)fields.gecos.string();
db.pw_dir = (char *)fields.home.string();
db.pw_shell = (char *)fields.shell.string();
db.pw_expire = fields.expire;
db.pw_fields = fields.fields;
}
static int _fill_r(struct passwd *in,
char *buffer, size_t bufsize,
struct passwd **out)
{
if (!in || !buffer) return Libc::Errno(EINVAL);
if (bufsize < sizeof(Passwd_fields)) return Libc::Errno(ERANGE);
Passwd_fields *fields = (Passwd_fields *)buffer;
_fill_passwd(*in, *fields);
*out = in;
return 0;
}
static struct passwd *_fill_static()
{
struct Passwd_storage {
struct passwd pwd;
Passwd_fields fields;
};
static Passwd_storage *db = nullptr;
if (!db)
db = (Passwd_storage *)malloc(sizeof(struct Passwd_storage));
_fill_passwd(db->pwd, db->fields);
return &db->pwd;
}
static int _passwd_index = 0;
extern "C" {
struct passwd *getpwent(void)
{
return (_passwd_index++ == 0)
? _fill_static()
: NULL;
}
int getpwent_r(struct passwd *in,
char *buffer, size_t bufsize,
struct passwd **out)
{
*out = NULL;
return _passwd_index++ == 0
? _fill_r(in, buffer, bufsize, out)
: 0;
}
struct passwd *getpwnam(const char *login)
{
struct passwd *result = _fill_static();
return (Genode::strcmp(login, result->pw_name) == 0)
? result : NULL;
}
int getpwnam_r(const char *login, struct passwd *in,
char *buffer, size_t bufsize,
struct passwd **out)
{
int rc = _fill_r(in, buffer, bufsize, out);
if (rc == 0 && *out && Genode::strcmp(login, in->pw_name) != 0)
*out = NULL;
return rc;
}
struct passwd *getpwuid(uid_t uid)
{
struct passwd *result = _fill_static();
return (uid == result->pw_uid)
? result : NULL;
}
int getpwuid_r(uid_t uid, struct passwd *in,
char *buffer, size_t bufsize,
struct passwd **out)
{
int rc = _fill_r(in, buffer, bufsize, out);
if (rc == 0 && *out && uid != in->pw_uid)
*out = NULL;
return rc;
}
int setpassent(int) { _passwd_index = 0; return 0; }
void setpwent(void) { _passwd_index = 0; }
void endpwent(void) { }
} /* extern "C" */

76
repos/libports/src/test/libc_getpwent/main.c Normal file
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@ -0,0 +1,76 @@
/*
* \brief Libc passwd database test
* \author Emery Hemingway
* \date 2018-07-16
*/
/*
* Copyright (C) 2018 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#include <sys/types.h>
#include <pwd.h>
#include <stdlib.h>
#include <stdio.h>
void print_db(char const *label, struct passwd *db)
{
if (db == NULL)
printf("[%s] NULL\n", label);
else
printf("[%s] user:%s uid:%d home:%s \n",
label, db->pw_name, db->pw_uid, db->pw_dir);
fflush(stderr);
}
int main(int argc, char **argv)
{
static char buf[4096];
struct passwd db;
struct passwd *ptr;
print_db("getpwent", getpwent());
print_db("getpwent", getpwent());
print_db("getpwent", getpwent());
setpwent();
getpwent_r(&db, buf, sizeof(buf), &ptr);
print_db("getpwent_r", ptr);
getpwent_r(&db, buf, sizeof(buf), &ptr);
print_db("getpwent_r", ptr);
getpwent_r(&db, buf, sizeof(buf), &ptr);
print_db("getpwent_r", ptr);
print_db("getpwnam root", getpwnam("root"));
print_db("getpwnam alice", getpwnam("alice"));
print_db("getpwnam bob", getpwnam("bob"));
setpassent(0);
getpwnam_r("root", &db, buf, sizeof(buf), &ptr);
print_db("getpwnam_r root", ptr);
getpwnam_r("alice", &db, buf, sizeof(buf), &ptr);
print_db("getpwnam_r alice", ptr);
getpwnam_r("bob", &db, buf, sizeof(buf), &ptr);
print_db("getpwnam_r bob", ptr);
print_db("getpwuid 0", getpwuid(0));
print_db("getpwuid 1", getpwuid(1));
print_db("getpwuid 2", getpwuid(2));
setpassent(1);
getpwuid_r(0, &db, buf, sizeof(buf), &ptr);
print_db("getpwuid_r 0", ptr);
getpwuid_r(1, &db, buf, sizeof(buf), &ptr);
print_db("getpwuid_r 1", ptr);
getpwuid_r(2, &db, buf, sizeof(buf), &ptr);
print_db("getpwuid_r 2", ptr);
endpwent();
return 0;
}

3
repos/libports/src/test/libc_getpwent/target.mk Normal file
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@ -0,0 +1,3 @@
TARGET = test-libc_getpwent
SRC_C = main.c
LIBS = posix