Check NSCD configuration file

https://fedorahosted.org/sssd/ticket/1785

nscd.conf file is now checked for the presence of caching settings for
databases controlled by SSSD. Syslog warning is now written only if NSCD
is running with interfering configuration or if configuration file
couldn't be loaded.

New configure option added to support non-standard locations
--with-nscd-conf=PATH (defaultly set to /etc/nscd.conf)

This is just a workaround until the following bugzilla is resolved:
https://bugzilla.redhat.com/show_bug.cgi?id=963908

4 files changed, 171 insertions, 6 deletions

diff --git a/src/conf_macros.m4 b/src/conf_macros.m4
index 26eb4acc..c72b3dd7 100644
--- a/src/conf_macros.m4
+++ b/src/conf_macros.m4
@@ -352,6 +352,20 @@ AC_DEFUN([WITH_NSCD],
     AC_DEFINE_UNQUOTED(HAVE_NSCD, $NSCD_PATH, [flush nscd cache after local domain operations])
   ])
 
+AC_DEFUN([WITH_NSCD_CONF],
+  [ AC_ARG_WITH([nscd_conf],
+                [AC_HELP_STRING([--with-nscd-conf=PATH], [Path to nscd.conf file [/etc/nscd.conf]])
+                ]
+               )
+
+    NSCD_CONF_PATH="/etc/nscd.conf"
+    if test x"$with_nscd_conf" != x; then
+        NSCD_CONF_PATH=$with_nscd_conf
+    fi
+    AC_DEFINE_UNQUOTED([NSCD_CONF_PATH], ["$NSCD_CONF_PATH"], [NSCD configuration file])
+  ])
+
+
 AC_DEFUN([WITH_SEMANAGE],
   [ AC_ARG_WITH([semanage],
                 [AC_HELP_STRING([--with-semanage],
diff --git a/src/monitor/monitor.c b/src/monitor/monitor.c
index bd22a951..8882e4db 100644
--- a/src/monitor/monitor.c
+++ b/src/monitor/monitor.c
@@ -2754,12 +2754,32 @@ int main(int argc, const char *argv[])
     /* Warn if nscd seems to be running */
     ret = check_file(NSCD_SOCKET_PATH, -1, -1, -1, CHECK_SOCK, NULL, false);
     if (ret == EOK) {
-        sss_log(SSS_LOG_NOTICE,
-                "nscd socket was detected.  Nscd caching capabilities "
-                "may conflict with SSSD for users and groups. It is "
-                "recommended not to run nscd in parallel with SSSD, unless "
-                "nscd is configured not to cache the passwd, group and "
-                "netgroup nsswitch maps.");
+        ret = sss_nscd_parse_conf(NSCD_CONF_PATH);
+
+        switch (ret) {
+            case ENOENT:
+                sss_log(SSS_LOG_NOTICE,
+                        "NSCD socket was detected. NSCD caching capabilities "
+                        "may conflict with SSSD for users and groups. It is "
+                        "recommended not to run NSCD in parallel with SSSD, "
+                        "unless NSCD is configured not to cache the passwd, "
+                        "group, netgroup and services nsswitch maps.");
+                break;
+
+            case EEXIST:
+                sss_log(SSS_LOG_NOTICE,
+                        "NSCD socket was detected and seems to be configured "
+                        "to cache some of the databases controlled by "
+                        "SSSD [passwd,group,netgroup,services]. It is "
+                        "recommended not to run NSCD in parallel with SSSD, "
+                        "unless NSCD is configured not to cache these.");
+                break;
+
+            case EOK:
+                DEBUG(SSSDBG_TRACE_FUNC, ("NSCD socket was detected and it "
+                            "seems to be configured not to interfere with "
+                            "SSSD's caching capabilities\n"));
+        }
     }
 
     /* Parse config file, fail if cannot be done */
diff --git a/src/util/nscd.c b/src/util/nscd.c
index b9f2ba88..2a06394d 100644
--- a/src/util/nscd.c
+++ b/src/util/nscd.c
@@ -95,3 +95,132 @@ int flush_nscd_cache(enum nscd_db flush_db)
     return EOK;
 }
 #endif
+
+/* NSCD config file parse and check */
+
+static unsigned int sss_nscd_check_service(char* svc_name)
+{
+    struct sss_nscd_db {
+        const char *svc_type_name;
+        unsigned int nscd_service_flag;
+    };
+
+    int i;
+    unsigned int ret = 0;
+    struct sss_nscd_db db[] = {
+        { "passwd",   0x0001 },
+        { "group",    0x0010 },
+        { "netgroup", 0x0100 },
+        { "services", 0x1000 },
+        { NULL,       0   }
+    };
+
+    if (svc_name == NULL) {
+        return ret;
+    }
+
+    for (i = 0; db[i].svc_type_name != NULL; i++) {
+        if (!strcmp(db[i].svc_type_name, svc_name)) {
+
+            ret = db[i].nscd_service_flag;
+            break;
+        }
+    }
+
+    return ret;
+}
+
+errno_t sss_nscd_parse_conf(const char *conf_path)
+{
+    FILE *fp;
+    int ret = EOK;
+    unsigned int occured = 0;
+    char *line, *entry, *service, *enabled, *pad;
+    size_t linelen = 0;
+
+    fp = fopen(conf_path, "r");
+    if (fp == NULL) {
+        DEBUG(SSSDBG_MINOR_FAILURE, ("Couldn't open NSCD configuration "
+                    "file [%s]\n", NSCD_CONF_PATH));
+        return ENOENT;
+    }
+
+    while (getline(&line, &linelen, fp) != -1) {
+
+        entry = NULL;
+        service = NULL;
+        enabled = NULL;
+
+        pad = strchr(line, '#');
+        if (pad != NULL) {
+            *pad = '\0';
+        }
+
+        if (line[0] == '\n' || line[0] == '\0') continue;
+
+        entry = line;
+        while (isspace(*entry) && *entry != '\0') {
+            entry++;
+        }
+
+        pad = entry;
+        while (!isspace(*pad) && *pad != '\0') {
+            pad++;
+        }
+
+        service = pad;
+        while (isspace(*service) && *service != '\0') {
+            service++;
+        }
+
+        *pad = '\0';
+        pad = service;
+        while (!isspace(*pad) && *pad != '\0') {
+            pad++;
+        }
+
+        enabled = pad;
+        while (isspace(*enabled) && *enabled != '\0') {
+            enabled++;
+        }
+
+        *pad = '\0';
+        pad = enabled;
+        while (!isspace(*pad) && *pad != '\0') {
+            pad++;
+        }
+        *pad = '\0';
+
+        if (entry   != NULL &&
+            service != NULL &&
+            enabled != NULL) {
+
+            if (!strcmp(entry, "enable-cache") &&
+                !strcmp(enabled, "yes")) {
+
+                occured |= sss_nscd_check_service(service);
+            }
+        }
+    };
+
+    ret = ferror(fp);
+    if (ret) {
+        DEBUG(SSSDBG_MINOR_FAILURE, ("Reading NSCD configuration file [%s] "
+              "ended with failure [%d]: %s.\n",
+              NSCD_CONF_PATH, ret, strerror(ret)));
+        ret = ENOENT;
+        goto done;
+    }
+
+    ret = EOK;
+    if (occured != 0) {
+        ret = EEXIST;
+        goto done;
+    }
+
+done:
+    free(line);
+    fclose(fp);
+
+    return ret;
+}
diff --git a/src/util/util.h b/src/util/util.h
index 56653038..bdb04a8f 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -499,6 +499,8 @@ enum nscd_db {
 
 int flush_nscd_cache(enum nscd_db flush_db);
 
+errno_t sss_nscd_parse_conf(const char *conf_path);
+
 /* from sss_tc_utf8.c */
 char *
 sss_tc_utf8_str_tolower(TALLOC_CTX *mem_ctx, const char *s);