sss_cache: Remove fastcache even if sssd is not running.

https://fedorahosted.org/sssd/ticket/1584

3 files changed, 152 insertions, 20 deletions

diff --git a/src/tools/sss_cache.c b/src/tools/sss_cache.c
index 84a53ddf..06b0099d 100644
--- a/src/tools/sss_cache.c
+++ b/src/tools/sss_cache.c
@@ -92,6 +92,7 @@ errno_t invalidate_entry(TALLOC_CTX *ctx, struct sysdb_ctx *sysdb,
 bool invalidate_entries(TALLOC_CTX *ctx, struct sysdb_ctx *sysdb,
                         enum sss_cache_entry entry_type, const char *filter,
                         const char *name);
+static int clear_fastcache(bool *sssd_nss_is_off);
 
 int main(int argc, const char *argv[])
 {
@@ -99,6 +100,7 @@ int main(int argc, const char *argv[])
     struct cache_tool_ctx *tctx = NULL;
     struct sysdb_ctx *sysdb;
     int i;
+    bool sssd_nss_is_off;
     bool skipped = true;
     FILE *clear_mc_flag;
 
@@ -143,29 +145,36 @@ int main(int argc, const char *argv[])
         ret = ENOENT;
         goto done;
     } else {
-        /*Local cache changed -> signal monitor to invalidate fastcache */
-        clear_mc_flag = fopen(SSS_NSS_MCACHE_DIR"/"CLEAR_MC_FLAG, "w");
-        if (clear_mc_flag == NULL) {
-            DEBUG(SSSDBG_CRIT_FAILURE,
-                  ("Failed to create clear_mc_flag file. "
-                  "Memory cache will not be cleared.\n"));
+        ret = clear_fastcache(&sssd_nss_is_off);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_CRIT_FAILURE, ("Failed to clear caches.\n"));
             goto done;
         }
-        ret = fclose(clear_mc_flag);
-        if (ret != 0) {
-            ret = errno;
-            DEBUG(SSSDBG_CRIT_FAILURE,
-                  ("Unable to close file descriptor: %s\n",
-                   strerror(ret)));
-             goto done;
-        }
+        if (!sssd_nss_is_off) {
+            /* sssd_nss is running -> signal monitor to invalidate fastcache */
+            clear_mc_flag = fopen(SSS_NSS_MCACHE_DIR"/"CLEAR_MC_FLAG, "w");
+            if (clear_mc_flag == NULL) {
+                DEBUG(SSSDBG_CRIT_FAILURE,
+                      ("Failed to create clear_mc_flag file. "
+                       "Memory cache will not be cleared.\n"));
+                goto done;
+            }
+            ret = fclose(clear_mc_flag);
+            if (ret != 0) {
+                ret = errno;
+                DEBUG(SSSDBG_CRIT_FAILURE,
+                      ("Unable to close file descriptor: %s\n",
+                       strerror(ret)));
+                goto done;
+            }
 
-        DEBUG(SSSDBG_TRACE_FUNC, ("Sending SIGHUP to monitor.\n"));
-        ret = signal_sssd(SIGHUP);
-        if (ret != EOK) {
-            DEBUG(SSSDBG_CRIT_FAILURE,
-                  ("Failed to send SIGHUP to monitor.\n"));
-            goto done;
+            DEBUG(SSSDBG_TRACE_FUNC, ("Sending SIGHUP to monitor.\n"));
+            ret = signal_sssd(SIGHUP);
+            if (ret != EOK) {
+                DEBUG(SSSDBG_CRIT_FAILURE,
+                      ("Failed to send SIGHUP to monitor.\n"));
+                goto done;
+            }
         }
     }
 
@@ -174,6 +183,33 @@ done:
     return ret;
 }
 
+static int clear_fastcache(bool *sssd_nss_is_off)
+{
+    int ret;
+    ret = sss_memcache_invalidate(SSS_NSS_MCACHE_DIR"/passwd");
+    if (ret != EOK) {
+        if (ret == EACCES) {
+            *sssd_nss_is_off = false;
+            return EOK;
+        } else {
+            return ret;
+        }
+    }
+
+    ret = sss_memcache_invalidate(SSS_NSS_MCACHE_DIR"/group");
+    if (ret != EOK) {
+        if (ret == EACCES) {
+            *sssd_nss_is_off = false;
+            return EOK;
+        } else {
+            return ret;
+        }
+    }
+
+    *sssd_nss_is_off = true;
+    return EOK;
+}
+
 bool invalidate_entries(TALLOC_CTX *ctx, struct sysdb_ctx *sysdb,
                         enum sss_cache_entry entry_type, const char *filter,
                         const char *name)
diff --git a/src/tools/tools_util.c b/src/tools/tools_util.c
index 049a4f58..99b79f17 100644
--- a/src/tools/tools_util.c
+++ b/src/tools/tools_util.c
@@ -35,6 +35,7 @@
 #include "db/sysdb.h"
 #include "tools/tools_util.h"
 #include "tools/sss_sync_ops.h"
+#include "util/mmap_cache.h"
 
 static int setup_db(struct tools_ctx *ctx)
 {
@@ -671,3 +672,96 @@ errno_t signal_sssd(int signum)
 
     return EOK;
 }
+
+static errno_t sss_mc_set_recycled(int fd)
+{
+    uint32_t w = SSS_MC_HEADER_RECYCLED;
+    struct sss_mc_header h;
+    off_t offset;
+    off_t pos;
+    int ret;
+
+
+    offset = MC_PTR_DIFF(&h.status, &h);
+
+    pos = lseek(fd, offset, SEEK_SET);
+    if (pos == -1) {
+        /* What do we do now ? */
+        return errno;
+    }
+
+    errno = 0;
+    ret = sss_atomic_write_s(fd, (uint8_t *)&w, sizeof(h.status));
+    if (ret == -1) {
+        return errno;
+    }
+
+    if (ret != sizeof(h.status)) {
+        /* Write error */
+        return EIO;
+    }
+
+    return EOK;
+}
+
+errno_t sss_memcache_invalidate(const char *mc_filename)
+{
+    int mc_fd = -1;
+    errno_t ret;
+    errno_t pret;
+    useconds_t t = 50000;
+    int retries = 2;
+
+    if (!mc_filename) {
+        return EINVAL;
+    }
+
+    mc_fd = open(mc_filename, O_RDWR);
+    if (mc_fd == -1) {
+        ret = errno;
+        if (ret == ENOENT) {
+            DEBUG(SSSDBG_TRACE_FUNC,("Memory cache file %s "
+                  "does not exist.\n", mc_filename));
+            return EOK;
+        } else {
+            DEBUG(SSSDBG_CRIT_FAILURE, ("Unable to open file %s: %s\n",
+                  mc_filename, strerror(ret)));
+            return ret;
+        }
+    }
+
+    ret = sss_br_lock_file(mc_fd, 0, 1, retries, t);
+    if (ret == EACCES) {
+        DEBUG(SSSDBG_TRACE_FUNC,
+              ("File %s already locked by someone else.\n", mc_filename));
+        goto done;
+    } else if (ret != EOK) {
+       DEBUG(SSSDBG_CRIT_FAILURE, ("Failed to lock file %s.\n", mc_filename));
+       goto done;
+    }
+    /* Mark the mc file as recycled. */
+    ret = sss_mc_set_recycled(mc_fd);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Failed to mark memory cache file %s "
+              "as recycled.\n", mc_filename));
+        goto done;
+    }
+
+    ret = EOK;
+done:
+    if (mc_fd != -1) {
+        /* Closing the file also releases the lock */
+        close(mc_fd);
+
+        /* Only unlink the file if invalidation was succesful */
+        if (ret == EOK) {
+            pret = unlink(mc_filename);
+            if (pret == -1) {
+                DEBUG(SSSDBG_MINOR_FAILURE,
+                      ("Failed to unlink file %s. "
+                       "Will be unlinked later by sssd_nss.\n"));
+            }
+        }
+    }
+    return ret;
+}
diff --git a/src/tools/tools_util.h b/src/tools/tools_util.h
index 1be17e8e..a83c8eea 100644
--- a/src/tools/tools_util.h
+++ b/src/tools/tools_util.h
@@ -104,6 +104,8 @@ int run_userdel_cmd(struct tools_ctx *tctx);
 
 errno_t signal_sssd(int signum);
 
+errno_t sss_memcache_invalidate(const char *mc_filename);
+
 /* from files.c */
 int remove_tree(const char *root);