in_tail: enable "real_name" support on the inotify backend

When in_tail watches a symbolic link, it occationally checks the
target file (as well as the symlink itself) to see if the log
file is rotated or not.

Previously the inotify backend cannot handle this well, since it
lacks the support for real_name in flb_tail_file struct. Evidently
this has been causing failures with in_tail/run_tests.sh.

This commit fixes it by adding that missing support.

Signed-off-by: Fujimoto Seiji <[email protected]>

Author: fujimotos

plugins/in_tail/tail_file.c

@@ -764,9 +764,7 @@ void flb_tail_file_remove(struct flb_tail_file *file)
 
     flb_free(file->buf_data);
     flb_free(file->name);
-#if !defined(__linux__) || !defined(FLB_HAVE_INOTIFY)
     flb_free(file->real_name);
-#endif
 
 #ifdef FLB_HAVE_METRICS
     flb_metrics_sum(FLB_TAIL_METRIC_F_CLOSED, 1, ctx->ins->metrics);
@@ -1134,7 +1132,6 @@ int flb_tail_file_name_dup(char *path, struct flb_tail_file *file)
     }
     file->name_len = strlen(file->name);
 
-#if !defined(__linux__) || !defined(FLB_HAVE_INOTIFY)
     if (file->real_name) {
         flb_free(file->real_name);
     }
@@ -1145,7 +1142,6 @@ int flb_tail_file_name_dup(char *path, struct flb_tail_file *file)
         file->name = NULL;
         return -1;
     }
-#endif
 
     return 0;
 }

plugins/in_tail/tail_file.h

@@ -84,11 +84,7 @@ static inline int flb_tail_target_file_name_cmp(char *name,
     name_a = flb_strdup(name);
     base_a = flb_strdup(basename(name_a));
 
-#if defined(__linux__) && defined(FLB_HAVE_INOTIFY)
-    name_b = flb_strdup(file->name);
-    base_b = basename(name_b);
-    ret = strcmp(base_a, base_b);
-#elif defined(FLB_SYSTEM_WINDOWS)
+#if defined(FLB_SYSTEM_WINDOWS)
     name_b = flb_strdup(file->real_name);
     base_b = basename(name_b);
     ret = _stricmp(base_a, base_b);

plugins/in_tail/tail_file_internal.h

@@ -41,9 +41,7 @@ struct flb_tail_file {
     uint64_t  link_inode;
     int   is_link;
     char *name;                 /* target file name given by scan routine */
-#if !defined(__linux) || !defined(FLB_HAVE_INOTIFY)
     char *real_name;            /* real file name in the file system */
-#endif
     size_t name_len;
     time_t rotated;
     off_t pending_bytes;