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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
#include "pal_config.h"
#include "pal_uid.h"
#include "pal_utilities.h"
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <grp.h>
#include <pwd.h>
// Linux c-libraries (glibc, musl) provide a thread-safe getgrouplist.
// OSX man page mentions explicitly the implementation is not thread safe,
// due to using getgrent.
#ifndef __linux__
#define USE_GROUPLIST_LOCK
#endif
#ifdef USE_GROUPLIST_LOCK
#include <pthread.h>
#endif
static int32_t ConvertNativePasswdToPalPasswd(int error, struct passwd* nativePwd, struct passwd* result, Passwd* pwd)
{
// positive error number returned -> failure other than entry-not-found
if (error != 0)
{
assert(error > 0);
memset(pwd, 0, sizeof(Passwd)); // managed out param must be initialized
return error;
}
// 0 returned with null result -> entry-not-found
if (result == NULL)
{
memset(pwd, 0, sizeof(Passwd)); // managed out param must be initialized
return -1; // shim convention for entry-not-found
}
// 0 returned with non-null result (guaranteed to be set to pwd arg) -> success
assert(result == nativePwd);
pwd->Name = nativePwd->pw_name;
pwd->Password = nativePwd->pw_passwd;
pwd->UserId = nativePwd->pw_uid;
pwd->GroupId = nativePwd->pw_gid;
pwd->UserInfo = nativePwd->pw_gecos;
pwd->HomeDirectory = nativePwd->pw_dir;
pwd->Shell = nativePwd->pw_shell;
return 0;
}
int32_t SystemNative_GetPwUidR(uint32_t uid, Passwd* pwd, char* buf, int32_t buflen)
{
assert(pwd != NULL);
assert(buf != NULL);
assert(buflen >= 0);
if (buflen < 0)
return EINVAL;
struct passwd nativePwd;
struct passwd* result;
int error;
while ((error = getpwuid_r(uid, &nativePwd, buf, Int32ToSizeT(buflen), &result)) == EINTR);
return ConvertNativePasswdToPalPasswd(error, &nativePwd, result, pwd);
}
int32_t SystemNative_GetPwNamR(const char* name, Passwd* pwd, char* buf, int32_t buflen)
{
assert(pwd != NULL);
assert(buf != NULL);
assert(buflen >= 0);
if (buflen < 0)
return EINVAL;
struct passwd nativePwd;
struct passwd* result;
int error;
while ((error = getpwnam_r(name, &nativePwd, buf, Int32ToSizeT(buflen), &result)) == EINTR);
return ConvertNativePasswdToPalPasswd(error, &nativePwd, result, pwd);
}
uint32_t SystemNative_GetEUid()
{
return geteuid();
}
uint32_t SystemNative_GetEGid()
{
return getegid();
}
int32_t SystemNative_SetEUid(uint32_t euid)
{
return seteuid(euid);
}
uint32_t SystemNative_GetUid()
{
return getuid();
}
#ifdef USE_GROUPLIST_LOCK
static pthread_mutex_t s_groupLock = PTHREAD_MUTEX_INITIALIZER;
#endif
#if !HAVE_GETGROUPLIST
int getgrouplist(const char *uname, gid_t agroup, gid_t *groups, int *groupCount)
{
int ngroups = 1;
int maxgroups = *groupCount;
if (groups)
{
groups[ngroups] = agroup;
}
if (maxgroups > 1)
{
if (groups)
groups[ngroups++] = agroup;
else
ngroups++;
}
setgrent();
int i;
int result = 0;
const struct group *group;
while ((group = getgrent()) != NULL)
{
if (groups)
{
bool found = false;
for (i = 0; i < ngroups; i++)
{
if (group->gr_gid == groups[i])
{
found = true;
break;
}
}
if (found)
break;
}
for (i = 0; group->gr_mem[i]; i++)
{
if (!strcmp(group->gr_mem[i], uname))
{
if (ngroups >= maxgroups)
{
result = -1;
break;
}
if (groups)
groups[ngroups++] = group->gr_gid;
else
ngroups++;
break;
}
}
}
endgrent();
*groupCount = ngroups;
return result;
}
#endif
int32_t SystemNative_GetGroupList(const char* name, uint32_t group, uint32_t* groups, int32_t* ngroups)
{
assert(name != NULL);
assert(groups != NULL);
assert(ngroups != NULL);
assert(*ngroups >= 0);
// The man page of getgrouplist doesn't explicitly mention the use of errno on error.
// glibc and musl implementation look like they return -1 for functions that fail with errno set.
// To be safe, we'll assume errno is set on error and handle EINTR.
int rv;
int groupsAvailable;
do
{
errno = 0;
groupsAvailable = *ngroups;
#ifdef USE_GROUPLIST_LOCK
rv = pthread_mutex_lock(&s_groupLock);
if (rv != 0)
{
errno = rv;
rv = -1;
break;
}
#endif
#ifdef __APPLE__
// On OSX groups are passed as a signed int.
rv = getgrouplist(name, (int)group, (int*)groups, &groupsAvailable);
#else
rv = getgrouplist(name, group, groups, &groupsAvailable);
#endif
#ifdef USE_GROUPLIST_LOCK
pthread_mutex_unlock(&s_groupLock);
#endif
// Check if the buffer is too small.
if (rv == -1 &&
(// if ngroups was updated to a higher value, the buffer was too small.
(groupsAvailable > *ngroups) ||
// OSX doesn't update ngroups when the buffer is too small.
// musl doesn't update ngroups when it encounters an error.
(groupsAvailable == *ngroups && errno == 0)))
{
// return an increased value for ngroups.
*ngroups = groupsAvailable > *ngroups ? groupsAvailable : *ngroups * 2;
return rv;
}
} while (rv == -1 && errno == EINTR);
*ngroups = rv >= 0 ? groupsAvailable : -1;
return rv;
}
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