commiting conditional_ldap.c

conditional_ldap.c

+#include <nss.h>
+#include <pwd.h>
+#include <shadow.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <dlfcn.h>
+
+static struct {
+  time_t mtime;
+  void *handle;
+  enum nss_status (*setpwent)(int i);
+  enum nss_status (*endpwent)(void);
+  enum nss_status (*getpwnam_r)(const char *name, 
+				struct passwd *pwd, 
+				char *buffer, 
+				size_t buflen, 
+				int *errnop);
+  enum nss_status (*getpwuid_r)(uid_t uid, 
+				struct passwd *pwd, 
+				char *buffer, 
+				size_t buflen, 
+				int *errnop);
+  enum nss_status (*getpwent_r)(struct passwd *result,
+				char *buffer, 
+				size_t buflen, 
+				int *errnop);
+  enum nss_status (*setspent)(int i);
+  enum nss_status (*endspent)(void);
+  enum nss_status (*getspent_r)(struct spwd *pwd, 
+				char *buffer, 
+				size_t buflen, 
+				int *errnop);
+  enum nss_status (*getspnam_r)(const char *name, 
+				struct spwd *pwd, 
+				char *buffer,
+				size_t buflen,
+				int *errnop);
+} ldap;
+
+__attribute__((constructor)) static void a()
+{
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+}
+
+__attribute__((destructor)) void b() 
+{
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (ldap.handle) {
+    dlclose(ldap.handle);
+  }
+}
+
+static int active()
+{
+  int result = 0;
+  struct stat st;
+
+  if (stat("/var/run/conditional_ldap", &st) == 0) {
+    if (st.st_mtime != ldap.mtime) {
+//      printf("rebind %ld\n", st.st_mtime);
+      if (ldap.handle) {
+	dlclose(ldap.handle);
+      }
+    }
+    ldap.handle = dlopen("libnss_ldap.so", RTLD_LAZY);
+    if (!ldap.handle) {
+      fprintf(stderr, "Failed to load ldap %s\n", dlerror());
+    } else {
+#define LOADSYM(SYM) ldap.SYM = dlsym(ldap.handle, "_nss_ldap_" # SYM)
+      LOADSYM(setpwent);
+      LOADSYM(endpwent);
+      LOADSYM(getpwnam_r);
+      LOADSYM(getpwuid_r);
+      LOADSYM(getpwent_r);
+      LOADSYM(setspent);
+      LOADSYM(endspent);
+      LOADSYM(getspent_r);
+      LOADSYM(getspnam_r);
+#undef LOADSYM
+      result = 1;
+    }
+   
+  }
+  return result;
+}
+
+enum nss_status _nss_conditional_ldap_setpwent(int i)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.setpwent) { 
+    result = ldap.setpwent(i);
+  } 
+  return result;
+}
+
+enum nss_status _nss_conditional_ldap_endpwent(void)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.endpwent) { 
+    result = ldap.endpwent();
+  } 
+  return result;
+}
+
+enum nss_status _nss_conditional_ldap_getpwnam_r(const char *name, 
+						 struct passwd *pwd, 
+						 char *buffer, 
+						 size_t buflen, 
+						 int *errnop)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.getpwnam_r) { 
+    result = ldap.getpwnam_r(name, pwd, buffer, buflen, errnop);
+  } 
+  return result;
+}
+
+enum nss_status _nss_conditional_ldap_getpwuid_r(uid_t uid, 
+						 struct passwd *pwd, 
+						 char *buffer, 
+						 size_t buflen, 
+						 int *errnop)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.getpwuid_r) { 
+    result = ldap.getpwuid_r(uid, pwd, buffer, buflen, errnop);
+  } 
+  return result;
+}
+ 
+enum nss_status _nss_conditional_ldap_getpwent_r(struct passwd *pwd,
+						 char *buffer, 
+						 size_t buflen, 
+						 int *errnop)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.getpwent_r) { 
+    result = ldap.getpwent_r(pwd, buffer, buflen, errnop);
+  } 
+  return result;
+}
+
+enum nss_status _nss_conditional_ldap_setspent(int i)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.setspent) { 
+    result = ldap.setspent(i);
+  } 
+  return result;
+}
+
+enum nss_status _nss_conditional_ldap_endspent(void)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.endspent) { 
+    result = ldap.endspent();
+  } 
+  return result;
+}
+ 
+enum nss_status _nss_conditional_ldap_getspent_r(struct spwd *pwd, 
+						 char *buffer, 
+						 size_t buflen, 
+						 int *errnop)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.getspent_r) { 
+    result = ldap.getspent_r(pwd, buffer, buflen, errnop);
+  } 
+  return result;
+}
+ 
+enum nss_status _nss_conditional_ldap_getspnam_r(const char *name, 
+						 struct spwd *pwd, 
+						 char *buffer,
+						 size_t buflen,
+						 int *errnop)
+{
+  enum nss_status result = NSS_STATUS_UNAVAIL;
+
+//  printf("%s:%d %s\n", __FUNCTION__, __LINE__, __TIME__);
+  if (active() && ldap.getspnam_r) { 
+    result = ldap.getspnam_r(name, pwd, buffer, buflen, errnop);
+  } 
+  return result;
+}
+