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authorPatrik Nyblom <[email protected]>2011-05-26 18:41:51 +0200
committerPatrik Nyblom <[email protected]>2011-05-26 18:41:51 +0200
commit62ff4caa39235fd0ba30b51f419309fcba06001d (patch)
tree8e82111a1a0f9d0fece38c6407033ef88a80560a /erts
parent41e6d95c4ca11598a5eb93901ce2fb0b758e9657 (diff)
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Add global lock for erlsrv to avoid races
Diffstat (limited to 'erts')
-rw-r--r--erts/etc/win32/erlsrv/erlsrv_interactive.c140
-rw-r--r--erts/etc/win32/erlsrv/erlsrv_interactive.h2
2 files changed, 120 insertions, 22 deletions
diff --git a/erts/etc/win32/erlsrv/erlsrv_interactive.c b/erts/etc/win32/erlsrv/erlsrv_interactive.c
index 13e029b364..8910be103b 100644
--- a/erts/etc/win32/erlsrv/erlsrv_interactive.c
+++ b/erts/etc/win32/erlsrv/erlsrv_interactive.c
@@ -841,6 +841,7 @@ int do_add_or_set(int argc, char **argv){
argv[0], service_name);
return 0;
}
+
int do_rename(int argc, char **argv){
RegEntry *current = empty_reg_tab();
RegEntry *dummy = empty_reg_tab();
@@ -1129,35 +1130,130 @@ void read_arguments(int *pargc, char ***pargv){
*pargc = argc;
*pargv = argv;
}
+
+/* Create a free-for-all ACL to set on the semaphore */
+PACL get_acl(PSECURITY_DESCRIPTOR secdescp)
+{
+ DWORD acl_length = 0;
+ PSID auth_users_sidp = NULL;
+ PACL aclp = NULL;
+ SID_IDENTIFIER_AUTHORITY ntauth = SECURITY_NT_AUTHORITY;
+
+ if(!InitializeSecurityDescriptor(secdescp, SECURITY_DESCRIPTOR_REVISION)) {
+ return NULL;
+ }
+
+ if(!AllocateAndInitializeSid(&ntauth,
+ 1,
+ SECURITY_AUTHENTICATED_USER_RID,
+ 0, 0, 0, 0, 0, 0, 0,
+ &auth_users_sidp)) {
+ return NULL;
+ }
+
+ acl_length = sizeof(ACL) +
+ sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD) +
+ GetLengthSid(auth_users_sidp);
+
+ if((aclp = (PACL) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, acl_length)) == NULL) {
+ FreeSid(auth_users_sidp);
+ return NULL;
+ }
+
+ if(!InitializeAcl(aclp, acl_length, ACL_REVISION)) {
+ FreeSid(auth_users_sidp);
+ HeapFree(GetProcessHeap(), 0, aclp);
+ return NULL;
+ }
+
+ if(!AddAccessAllowedAce(aclp, ACL_REVISION, SEMAPHORE_ALL_ACCESS, auth_users_sidp)) {
+ FreeSid(auth_users_sidp);
+ HeapFree(GetProcessHeap(), 0, aclp);
+ return NULL;
+ }
+
+ if(!SetSecurityDescriptorDacl(secdescp, TRUE, aclp, FALSE)) {
+ FreeSid(auth_users_sidp);
+ HeapFree(GetProcessHeap(), 0, aclp);
+ return NULL;
+ }
+ return aclp;
+}
+
+static HANDLE lock_semaphore = NULL;
+
+int take_lock(void) {
+ SECURITY_ATTRIBUTES attr;
+ PACL aclp;
+ SECURITY_DESCRIPTOR secdesc;
+
+ if ((aclp = get_acl(&secdesc)) == NULL) {
+ return -1;
+ }
+
+ memset(&attr,0,sizeof(attr));
+ attr.nLength = sizeof(attr);
+ attr.lpSecurityDescriptor = &secdesc;
+ attr.bInheritHandle = FALSE;
+
+ if ((lock_semaphore = CreateSemaphore(&attr, 1, 1, ERLSRV_INTERACTIVE_GLOBAL_SEMAPHORE)) == NULL) {
+ return -1;
+ }
+
+ if (WaitForSingleObject(lock_semaphore,INFINITE) != WAIT_OBJECT_0) {
+ return -1;
+ }
+
+ HeapFree(GetProcessHeap(), 0, aclp);
+ return 0;
+}
+
+void release_lock(void) {
+ ReleaseSemaphore(lock_semaphore,1,NULL);
+}
+
int interactive_main(int argc, char **argv){
char *action = argv[1];
-
+ int res;
+
+ if (take_lock() != 0) {
+ fprintf(stderr,"%s: unable to acquire global lock (%s).\n",argv[0],
+ ERLSRV_INTERACTIVE_GLOBAL_SEMAPHORE);
+ return 1;
+ }
+
if(!_stricmp(action,"readargs")){
- read_arguments(&argc,&argv);
- action = argv[1];
+ read_arguments(&argc,&argv);
+ action = argv[1];
}
if(!_stricmp(action,"set") || !_stricmp(action,"add"))
- return do_add_or_set(argc,argv);
- if(!_stricmp(action,"rename"))
- return do_rename(argc,argv);
- if(!_stricmp(action,"remove"))
- return do_remove(argc,argv);
- if(!_stricmp(action,"list"))
- return do_list(argc,argv);
- if(!_stricmp(action,"start") ||
- !_stricmp(action,"stop") ||
- !_stricmp(action,"enable") ||
- !_stricmp(action,"disable"))
- return do_manage(argc,argv);
- if(_stricmp(action,"?") &&
- _stricmp(action,"/?") &&
- _stricmp(action,"-?") &&
- *action != 'h' &&
- *action != 'H')
+ res = do_add_or_set(argc,argv);
+ else if(!_stricmp(action,"rename"))
+ res = do_rename(argc,argv);
+ else if(!_stricmp(action,"remove"))
+ res = do_remove(argc,argv);
+ else if(!_stricmp(action,"list"))
+ res = do_list(argc,argv);
+ else if(!_stricmp(action,"start") ||
+ !_stricmp(action,"stop") ||
+ !_stricmp(action,"enable") ||
+ !_stricmp(action,"disable"))
+ res = do_manage(argc,argv);
+ else if(_stricmp(action,"?") &&
+ _stricmp(action,"/?") &&
+ _stricmp(action,"-?") &&
+ *action != 'h' &&
+ *action != 'H') {
fprintf(stderr,"%s: action %s not implemented.\n",argv[0],action);
- do_usage(argv[0]);
- return 1;
+ do_usage(argv[0]);
+ res = 1;
+ } else {
+ do_usage(argv[0]);
+ res = 0;
+ }
+ release_lock();
+ return res;
}
diff --git a/erts/etc/win32/erlsrv/erlsrv_interactive.h b/erts/etc/win32/erlsrv/erlsrv_interactive.h
index deacf81899..602da24575 100644
--- a/erts/etc/win32/erlsrv/erlsrv_interactive.h
+++ b/erts/etc/win32/erlsrv/erlsrv_interactive.h
@@ -19,6 +19,8 @@
#ifndef _ERLSRV_INTERACTIVE_H
#define _ERLSRV_INTERACTIVE_H
+#define ERLSRV_INTERACTIVE_GLOBAL_SEMAPHORE "{468d6954-e355-415f-968f-d257cb0feef4}"
+
int interactive_main(int argc, char **argv);
#endif /* _ERLSRV_INTERACTIVE_H */