Move back to using per-thread credentials on Linux. Fixes the glibc native AIO lost wakeup problem.

See this post:

https://lists.samba.org/archive/samba-technical/2012-June/085101.html

for details.

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Fri Jun 29 03:57:45 CEST 2012 on sn-devel-104

3 files changed, 46 insertions, 12 deletions

diff --git a/lib/replace/libreplace.m4 b/lib/replace/libreplace.m4
index ad0f90411e..d298b9242b 100644
--- a/lib/replace/libreplace.m4
+++ b/lib/replace/libreplace.m4
@@ -124,8 +124,10 @@ AC_CHECK_HEADERS(sys/mount.h mntent.h)
 AC_CHECK_HEADERS(stropts.h)
 AC_CHECK_HEADERS(unix.h)
 AC_CHECK_HEADERS(malloc.h)
+AC_CHECK_HEADERS(syscall.h)
+AC_CHECK_HEADERS(sys/syscall.h)
 
-AC_CHECK_FUNCS(seteuid setreuid setresuid setegid setregid setresgid)
+AC_CHECK_FUNCS(syscall setuid seteuid setreuid setresuid setgid setegid setregid setresgid setgroups)
 AC_CHECK_FUNCS(chroot bzero strerror strerror_r memalign posix_memalign getpagesize)
 AC_CHECK_FUNCS(vsyslog setlinebuf mktime ftruncate chsize rename)
 AC_CHECK_FUNCS(waitpid wait4 strlcpy strlcat initgroups memmove strdup)
diff --git a/lib/replace/wscript b/lib/replace/wscript
index 68138cf8ed..157296b298 100644
--- a/lib/replace/wscript
+++ b/lib/replace/wscript
@@ -163,7 +163,7 @@ def configure(conf):
 
     conf.CHECK_FUNCS('shl_load shl_unload shl_findsym')
     conf.CHECK_FUNCS('pipe strftime srandom random srand rand usleep setbuffer')
-    conf.CHECK_FUNCS('lstat getpgrp utime utimes seteuid setreuid setresuid setegid')
+    conf.CHECK_FUNCS('lstat getpgrp utime utimes setuid seteuid setreuid setresuid setgid setegid')
     conf.CHECK_FUNCS('setregid setresgid chroot strerror vsyslog setlinebuf mktime')
     conf.CHECK_FUNCS('ftruncate chsize rename waitpid wait4')
     conf.CHECK_FUNCS('initgroups pread pwrite strndup strcasestr')
@@ -207,7 +207,7 @@ def configure(conf):
     conf.CHECK_FUNCS('if_nametoindex strerror_r')
     conf.CHECK_FUNCS('getdirentries getdents syslog')
     conf.CHECK_FUNCS('gai_strerror get_current_dir_name')
-    conf.CHECK_FUNCS('timegm getifaddrs freeifaddrs mmap setgroups setsid')
+    conf.CHECK_FUNCS('timegm getifaddrs freeifaddrs mmap setgroups syscall setsid')
     conf.CHECK_FUNCS('getgrent_r getgrgid_r getgrnam_r getgrouplist getpagesize')
     conf.CHECK_FUNCS('getpwent_r getpwnam_r getpwuid_r epoll_create')
 
diff --git a/lib/util/setid.c b/lib/util/setid.c
index 8b2efc076f..66c06397ee 100644
--- a/lib/util/setid.c
+++ b/lib/util/setid.c
@@ -70,10 +70,22 @@ int samba_setgroups(size_t setlen, const gid_t *gidset);
 
 #include "../lib/util/setid.h"
 
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+#if defined(HAVE_SYSCALL_H)
+#include <syscall.h>
+#endif
+
+#if defined(HAVE_SYS_SYSCALL_H)
+#include <sys/syscall.h>
+#endif
+#endif
+
 /* All the setXX[ug]id functions and setgroups Samba uses. */
 int samba_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 {
-#if defined(HAVE_SETRESUID)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	return syscall(SYS_setresuid, ruid, euid, suid);
+#elif defined(HAVE_SETRESUID)
 	return setresuid(ruid, euid, suid);
 #else
 	errno = ENOSYS;
@@ -83,7 +95,9 @@ int samba_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 
 int samba_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 {
-#if defined(HAVE_SETRESGID)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	return syscall(SYS_setresgid, rgid, egid, sgid);
+#elif defined(HAVE_SETRESGID)
 	return setresgid(rgid, egid, sgid);
 #else
 	errno = ENOSYS;
@@ -93,7 +107,9 @@ int samba_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 
 int samba_setreuid(uid_t ruid, uid_t euid)
 {
-#if defined(HAVE_SETREUID)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	return syscall(SYS_setreuid, ruid, euid);
+#elif defined(HAVE_SETREUID)
 	return setreuid(ruid, euid);
 #else
 	errno = ENOSYS;
@@ -103,7 +119,9 @@ int samba_setreuid(uid_t ruid, uid_t euid)
 
 int samba_setregid(gid_t rgid, gid_t egid)
 {
-#if defined(HAVE_SETREGID)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	return syscall(SYS_setregid, rgid, egid);
+#elif defined(HAVE_SETREGID)
 	return setregid(rgid, egid);
 #else
 	errno = ENOSYS;
@@ -113,7 +131,10 @@ int samba_setregid(gid_t rgid, gid_t egid)
 
 int samba_seteuid(uid_t euid)
 {
-#if defined(HAVE_SETEUID)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	/* seteuid is not a separate system call. */
+	return syscall(SYS_setresuid, -1, euid, -1);
+#elif defined(HAVE_SETEUID)
 	return seteuid(euid);
 #else
 	errno = ENOSYS;
@@ -123,7 +144,10 @@ int samba_seteuid(uid_t euid)
 
 int samba_setegid(gid_t egid)
 {
-#if defined(HAVE_SETEGID)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	/* setegid is not a separate system call. */
+	return syscall(SYS_setresgid, -1, egid, -1);
+#elif defined(HAVE_SETEGID)
 	return setegid(egid);
 #else
 	errno = ENOSYS;
@@ -133,7 +157,9 @@ int samba_setegid(gid_t egid)
 
 int samba_setuid(uid_t uid)
 {
-#if defined(HAVE_SETUID)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	return syscall(SYS_setuid, uid);
+#elif defined(HAVE_SETUID)
 	return setuid(uid);
 #else
 	errno = ENOSYS;
@@ -143,7 +169,9 @@ int samba_setuid(uid_t uid)
 
 int samba_setgid(gid_t gid)
 {
-#if defined(HAVE_SETGID)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	return syscall(SYS_setgid, gid);
+#elif defined(HAVE_SETGID)
 	return setgid(gid);
 #else
 	errno = ENOSYS;
@@ -156,6 +184,7 @@ int samba_setuidx(int flags, uid_t uid)
 #if defined(HAVE_SETUIDX)
 	return setuidx(flags, uid);
 #else
+	/* USE_LINUX_THREAD_CREDENTIALS doesn't have this. */
 	errno = ENOSYS;
 	return -1;
 #endif
@@ -166,6 +195,7 @@ int samba_setgidx(int flags, gid_t gid)
 #if defined(HAVE_SETGIDX)
 	return setgidx(flags, gid);
 #else
+	/* USE_LINUX_THREAD_CREDENTIALS doesn't have this. */
 	errno = ENOSYS;
 	return -1;
 #endif
@@ -173,7 +203,9 @@ int samba_setgidx(int flags, gid_t gid)
 
 int samba_setgroups(size_t setlen, const gid_t *gidset)
 {
-#if defined(HAVE_SETGROUPS)
+#if defined(USE_LINUX_THREAD_CREDENTIALS)
+	return syscall(SYS_setgroups, setlen, gidset);
+#elif defined(HAVE_SETGROUPS)
 	return setgroups(setlen, gidset);
 #else
 	errno = ENOSYS;