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Clean up messy API for src/port/thread.c.

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The point of this patch is to reduce inclusion spam by not needing
to #include <netdb.h> or <pwd.h> in port.h (which is read by every
compile in our tree).  To do that, we must remove port.h's
declarations of pqGetpwuid and pqGethostbyname.

pqGethostbyname is only used, and is only ever likely to be used,
in src/port/getaddrinfo.c --- which isn't even built on most
platforms, making pqGethostbyname dead code for most people.
Hence, deal with that by just moving it into getaddrinfo.c.

To clean up pqGetpwuid, invent a couple of simple wrapper
functions with less-messy APIs.  This allows removing some
duplicate error-handling code, too.

In passing, remove thread.c from the MSVC build, since it
contains nothing we use on Windows.

Noted while working on 376ce3e40.

Discussion: https://postgr.es/m/1634252654444.90107@mit.edu
This commit is contained in:
Tom Lane 2022-01-11 13:46:12 -05:00
parent 7fa945b857
commit 98e93a1fc9
11 changed files with 160 additions and 112 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/backend/libpq/auth.c
View File

@ -18,6 +18,7 @@
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <pwd.h>
#include <unistd.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>

1
src/bin/psql/common.c
View File

@ -10,6 +10,7 @@
#include <ctype.h>
#include <limits.h>
#include <math.h>
#include <pwd.h>
#include <signal.h>
#ifndef WIN32
#include <unistd.h> /* for write() */

14
src/include/port.h
View File

@ -14,8 +14,6 @@
#define PG_PORT_H
#include <ctype.h>
#include <netdb.h>
#include <pwd.h>
/*
* Windows has enough specialized port stuff that we push most of it off
@ -484,18 +482,12 @@ extern char *dlerror(void);
#define RTLD_GLOBAL 0
#endif
/* thread.h */
/* thread.c */
#ifndef WIN32
extern int pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer,
size_t buflen, struct passwd **result);
extern bool pg_get_user_name(uid_t user_id, char *buffer, size_t buflen);
extern bool pg_get_user_home_dir(uid_t user_id, char *buffer, size_t buflen);
#endif
extern int pqGethostbyname(const char *name,
struct hostent *resultbuf,
char *buffer, size_t buflen,
struct hostent **result,
int *herrno);
extern void pg_qsort(void *base, size_t nel, size_t elsize,
int (*cmp) (const void *, const void *));
extern int pg_qsort_strcmp(const void *a, const void *b);

54
src/interfaces/libpq/fe-auth.c
View File

@ -35,7 +35,6 @@
#ifndef MAXHOSTNAMELEN
#include <netdb.h> /* for MAXHOSTNAMELEN on some */
#endif
#include <pwd.h>
#endif
#include "common/md5.h"
@ -1099,14 +1098,17 @@ pg_fe_sendauth(AuthRequest areq, int payloadlen, PGconn *conn)
/*
* pg_fe_getauthname
* pg_fe_getusername
*
* Returns a pointer to malloc'd space containing whatever name the user
* has authenticated to the system. If there is an error, return NULL,
* and append a suitable error message to *errorMessage if that's not NULL.
* Returns a pointer to malloc'd space containing the name of the
* specified user_id. If there is an error, return NULL, and append
* a suitable error message to *errorMessage if that's not NULL.
*
* Caution: on Windows, the user_id argument is ignored, and we always
* fetch the current user's name.
*/
char *
pg_fe_getauthname(PQExpBuffer errorMessage)
pg_fe_getusername(uid_t user_id, PQExpBuffer errorMessage)
{
char *result = NULL;
const char *name = NULL;
@ -1116,17 +1118,13 @@ pg_fe_getauthname(PQExpBuffer errorMessage)
char username[256 + 1];
DWORD namesize = sizeof(username);
#else
uid_t user_id = geteuid();
char pwdbuf[BUFSIZ];
struct passwd pwdstr;
struct passwd *pw = NULL;
int pwerr;
#endif
/*
* Some users are using configure --enable-thread-safety-force, so we
* might as well do the locking within our library to protect
* pqGetpwuid(). In fact, application developers can use getpwuid() in
* getpwuid(). In fact, application developers can use getpwuid() in
* their application if they use the locking call we provide, or install
* their own locking function using PQregisterThreadLock().
*/
@ -1140,21 +1138,10 @@ pg_fe_getauthname(PQExpBuffer errorMessage)
libpq_gettext("user name lookup failure: error code %lu\n"),
GetLastError());
#else
pwerr = pqGetpwuid(user_id, &pwdstr, pwdbuf, sizeof(pwdbuf), &pw);
if (pw != NULL)
name = pw->pw_name;
if (pg_get_user_name(user_id, pwdbuf, sizeof(pwdbuf)))
name = pwdbuf;
else if (errorMessage)
{
if (pwerr != 0)
appendPQExpBuffer(errorMessage,
libpq_gettext("could not look up local user ID %d: %s\n"),
(int) user_id,
strerror_r(pwerr, pwdbuf, sizeof(pwdbuf)));
else
appendPQExpBuffer(errorMessage,
libpq_gettext("local user with ID %d does not exist\n"),
(int) user_id);
}
appendPQExpBuffer(errorMessage, "%s\n", pwdbuf);
#endif
if (name)
@ -1170,6 +1157,23 @@ pg_fe_getauthname(PQExpBuffer errorMessage)
return result;
}
/*
* pg_fe_getauthname
*
* Returns a pointer to malloc'd space containing whatever name the user
* has authenticated to the system. If there is an error, return NULL,
* and append a suitable error message to *errorMessage if that's not NULL.
*/
char *
pg_fe_getauthname(PQExpBuffer errorMessage)
{
#ifdef WIN32
return pg_fe_getusername(0, errorMessage);
#else
return pg_fe_getusername(geteuid(), errorMessage);
#endif
}
/*
* PQencryptPassword -- exported routine to encrypt a password with MD5

1
src/interfaces/libpq/fe-auth.h
View File

@ -20,6 +20,7 @@
/* Prototypes for functions in fe-auth.c */
extern int pg_fe_sendauth(AuthRequest areq, int payloadlen, PGconn *conn);
extern char *pg_fe_getusername(uid_t user_id, PQExpBuffer errorMessage);
extern char *pg_fe_getauthname(PQExpBuffer errorMessage);
/* Mechanisms in fe-auth-scram.c */

40
src/interfaces/libpq/fe-connect.c
View File

@ -2813,10 +2813,7 @@ keep_going: /* We will come back to here until there is
IS_AF_UNIX(conn->raddr.addr.ss_family))
{
#ifndef WIN32
char pwdbuf[BUFSIZ];
struct passwd pass_buf;
struct passwd *pass;
int passerr;
char *remote_username;
#endif
uid_t uid;
gid_t gid;
@ -2839,28 +2836,20 @@ keep_going: /* We will come back to here until there is
}
#ifndef WIN32
passerr = pqGetpwuid(uid, &pass_buf, pwdbuf, sizeof(pwdbuf), &pass);
if (pass == NULL)
{
if (passerr != 0)
appendPQExpBuffer(&conn->errorMessage,
libpq_gettext("could not look up local user ID %d: %s\n"),
(int) uid,
strerror_r(passerr, sebuf, sizeof(sebuf)));
else
appendPQExpBuffer(&conn->errorMessage,
libpq_gettext("local user with ID %d does not exist\n"),
(int) uid);
goto error_return;
}
remote_username = pg_fe_getusername(uid,
&conn->errorMessage);
if (remote_username == NULL)
goto error_return; /* message already logged */
if (strcmp(pass->pw_name, conn->requirepeer) != 0)
if (strcmp(remote_username, conn->requirepeer) != 0)
{
appendPQExpBuffer(&conn->errorMessage,
libpq_gettext("requirepeer specifies \"%s\", but actual peer user name is \"%s\"\n"),
conn->requirepeer, pass->pw_name);
conn->requirepeer, remote_username);
free(remote_username);
goto error_return;
}
free(remote_username);
#else /* WIN32 */
/* should have failed with ENOSYS above */
Assert(false);
@ -7271,16 +7260,7 @@ pqGetHomeDirectory(char *buf, int bufsize)
home = getenv("HOME");
if (home == NULL || home[0] == '\0')
{
char pwdbuf[BUFSIZ];
struct passwd pwdstr;
struct passwd *pwd = NULL;
(void) pqGetpwuid(geteuid(), &pwdstr, pwdbuf, sizeof(pwdbuf), &pwd);
if (pwd == NULL)
return false;
home = pwd->pw_dir;
}
return pg_get_user_home_dir(geteuid(), buf, bufsize);
strlcpy(buf, home, bufsize);
return true;
#else

4
src/port/Makefile
View File

@ -84,6 +84,10 @@ libpgport.a: $(OBJS)
rm -f $@
$(AR) $(AROPT) $@ $^
# getaddrinfo.o and getaddrinfo_shlib.o need PTHREAD_CFLAGS (but getaddrinfo_srv.o does not)
getaddrinfo.o: CFLAGS+=$(PTHREAD_CFLAGS)
getaddrinfo_shlib.o: CFLAGS+=$(PTHREAD_CFLAGS)
# thread.o and thread_shlib.o need PTHREAD_CFLAGS (but thread_srv.o does not)
thread.o: CFLAGS+=$(PTHREAD_CFLAGS)
thread_shlib.o: CFLAGS+=$(PTHREAD_CFLAGS)

44
src/port/getaddrinfo.c
View File

@ -34,6 +34,14 @@
#include "port/pg_bswap.h"
#ifdef FRONTEND
static int pqGethostbyname(const char *name,
struct hostent *resultbuf,
char *buffer, size_t buflen,
struct hostent **result,
int *herrno);
#endif
#ifdef WIN32
/*
* The native routines may or may not exist on the Windows platform we are on,
@ -394,3 +402,39 @@ getnameinfo(const struct sockaddr *sa, int salen,
return 0;
}
/*
* Wrapper around gethostbyname() or gethostbyname_r() to mimic
* POSIX gethostbyname_r() behaviour, if it is not available or required.
*/
#ifdef FRONTEND
static int
pqGethostbyname(const char *name,
struct hostent *resultbuf,
char *buffer, size_t buflen,
struct hostent **result,
int *herrno)
{
#if defined(ENABLE_THREAD_SAFETY) && defined(HAVE_GETHOSTBYNAME_R)
/*
* broken (well early POSIX draft) gethostbyname_r() which returns 'struct
* hostent *'
*/
*result = gethostbyname_r(name, resultbuf, buffer, buflen, herrno);
return (*result == NULL) ? -1 : 0;
#else
/* no gethostbyname_r(), just use gethostbyname() */
*result = gethostbyname(name);
if (*result != NULL)
*herrno = h_errno;
if (*result != NULL)
return 0;
else
return -1;
#endif
}
#endif /* FRONTEND */

11
src/port/path.c
View File

@ -815,16 +815,7 @@ get_home_path(char *ret_path)
home = getenv("HOME");
if (home == NULL || home[0] == '\0')
{
char pwdbuf[BUFSIZ];
struct passwd pwdstr;
struct passwd *pwd = NULL;
(void) pqGetpwuid(geteuid(), &pwdstr, pwdbuf, sizeof(pwdbuf), &pwd);
if (pwd == NULL)
return false;
home = pwd->pw_dir;
}
return pg_get_user_home_dir(geteuid(), ret_path, MAXPGPATH);
strlcpy(ret_path, home, MAXPGPATH);
return true;
#else

100
src/port/thread.c
View File

@ -45,10 +45,9 @@
* use *_r function names if they exit
* (*_THREADSAFE=yes)
* use non-*_r functions if they are thread-safe
*
* One thread-safe solution for gethostbyname() might be to use getaddrinfo().
*/
#ifndef WIN32
/*
* Wrapper around getpwuid() or getpwuid_r() to mimic POSIX getpwuid_r()
@ -60,8 +59,7 @@
* error during lookup: returns an errno code, *result is NULL
* (caller should *not* assume that the errno variable is set)
*/
#ifndef WIN32
int
static int
pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer,
size_t buflen, struct passwd **result)
{
@ -75,42 +73,74 @@ pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer,
return (*result == NULL) ? errno : 0;
#endif
}
#endif
/*
* Wrapper around gethostbyname() or gethostbyname_r() to mimic
* POSIX gethostbyname_r() behaviour, if it is not available or required.
* This function is called _only_ by our getaddrinfo() portability function.
* pg_get_user_name - get the name of the user with the given ID
*
* On success, the user name is returned into the buffer (of size buflen),
* and "true" is returned. On failure, a localized error message is
* returned into the buffer, and "false" is returned.
*/
#ifndef HAVE_GETADDRINFO
int
pqGethostbyname(const char *name,
struct hostent *resultbuf,
char *buffer, size_t buflen,
struct hostent **result,
int *herrno)
bool
pg_get_user_name(uid_t user_id, char *buffer, size_t buflen)
{
#if defined(FRONTEND) && defined(ENABLE_THREAD_SAFETY) && defined(HAVE_GETHOSTBYNAME_R)
char pwdbuf[BUFSIZ];
struct passwd pwdstr;
struct passwd *pw = NULL;
int pwerr;
/*
* broken (well early POSIX draft) gethostbyname_r() which returns 'struct
* hostent *'
*/
*result = gethostbyname_r(name, resultbuf, buffer, buflen, herrno);
return (*result == NULL) ? -1 : 0;
#else
/* no gethostbyname_r(), just use gethostbyname() */
*result = gethostbyname(name);
if (*result != NULL)
*herrno = h_errno;
if (*result != NULL)
return 0;
pwerr = pqGetpwuid(user_id, &pwdstr, pwdbuf, sizeof(pwdbuf), &pw);
if (pw != NULL)
{
strlcpy(buffer, pw->pw_name, buflen);
return true;
}
if (pwerr != 0)
snprintf(buffer, buflen,
_("could not look up local user ID %d: %s"),
(int) user_id,
strerror_r(pwerr, pwdbuf, sizeof(pwdbuf)));
else
return -1;
#endif
snprintf(buffer, buflen,
_("local user with ID %d does not exist"),
(int) user_id);
return false;
}
#endif
/*
* pg_get_user_home_dir - get the home directory of the user with the given ID
*
* On success, the directory path is returned into the buffer (of size buflen),
* and "true" is returned. On failure, a localized error message is
* returned into the buffer, and "false" is returned.
*
* Note that this does not incorporate the common behavior of checking
* $HOME first, since it's independent of which user_id is queried.
*/
bool
pg_get_user_home_dir(uid_t user_id, char *buffer, size_t buflen)
{
char pwdbuf[BUFSIZ];
struct passwd pwdstr;
struct passwd *pw = NULL;
int pwerr;
pwerr = pqGetpwuid(user_id, &pwdstr, pwdbuf, sizeof(pwdbuf), &pw);
if (pw != NULL)
{
strlcpy(buffer, pw->pw_dir, buflen);
return true;
}
if (pwerr != 0)
snprintf(buffer, buflen,
_("could not look up local user ID %d: %s"),
(int) user_id,
strerror_r(pwerr, pwdbuf, sizeof(pwdbuf)));
else
snprintf(buffer, buflen,
_("local user with ID %d does not exist"),
(int) user_id);
return false;
}
#endif /* !WIN32 */

2
src/tools/msvc/Mkvcbuild.pm
View File

@ -106,7 +106,7 @@ sub mkvcbuild
pread.c preadv.c pwrite.c pwritev.c pg_bitutils.c
pg_strong_random.c pgcheckdir.c pgmkdirp.c pgsleep.c pgstrcasecmp.c
pqsignal.c mkdtemp.c qsort.c qsort_arg.c bsearch_arg.c quotes.c system.c
strerror.c tar.c thread.c
strerror.c tar.c
win32env.c win32error.c win32ntdll.c
win32security.c win32setlocale.c win32stat.c);