Detect stream write failure reliably; new fn: lvm_fclose; use dm_fclose

* lib/misc/lvm-file.c (lvm_fclose): New function.
* lib/misc/lvm-file.h (lvm_fclose): Declare it.
* lib/config/config.c (write_config_file): Use the new function to detect
and diagnose unlikely write failure.
* lib/filters/filter-persistent.c (persistent_filter_dump): Likewise.
* lib/format_text/archive.c (archive_vg): Likewise.
* lib/format_text/format-text.c (_vg_write_file): Likewise.
* lib/log/log.c (fin_log): Similar, but use dm_fclose directly.
Include "\n" at end of each fprintf format string.

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.28 -
 ================================
+  Detect stream write failure reliably; new fn: lvm_fclose; use dm_fclose
   Fix clvmd if compiled with gulm support. (2.02.26)
   Trivial fix to lvdisplay man page.
   Add vg_lock_and_read() external library function.

lib/config/config.c

@@ -20,6 +20,7 @@
 #include "str_list.h"
 #include "toolcontext.h"
 #include "lvm-string.h"
+#include "lvm-file.h"
 
 #include <sys/stat.h>
 #include <sys/mman.h>
@@ -520,8 +521,8 @@ int write_config_file(struct config_tree *cft, const char *file,
 		argv++;
 	}
 
-	if (outline.fp && fclose(outline.fp)) {
+	if (outline.fp && lvm_fclose(outline.fp, file)) {
-		log_sys_error("fclose", file);
+		stack;
 		r = 0;
 	}
 

lib/filters/filter-persistent.c

@@ -239,10 +239,8 @@ int persistent_filter_dump(struct dev_filter *f)
 	/* _write_array(pf, fp, "invalid_devices", PF_BAD_DEVICE); */
 
 	fprintf(fp, "}\n");
-	if (fclose(fp)) {
+	if (lvm_fclose(fp, tmp_file))
-		log_sys_error("fclose", tmp_file);
+		goto_out;
-		goto out;
-	}
 
 	if (rename(tmp_file, pf->file))
 		log_error("%s: rename to %s failed: %s", tmp_file, pf->file,

lib/format_text/archive.c

@@ -261,11 +261,8 @@ int archive_vg(struct volume_group *vg,
 		return 0;
 	}
 
-	if (fclose(fp)) {
+	if (lvm_fclose(fp, temp_file))
-		log_sys_error("fclose", temp_file);
+		return_0; /* Leave file behind as evidence of failure */
-		/* Leave file behind as evidence of failure */
-		return 0;
-	}
 
 	/*
 	 * Now we want to rename this file to <vg>_index.vg.

lib/format_text/format-text.c

@@ -892,10 +892,8 @@ static int _vg_write_file(struct format_instance *fid, struct volume_group *vg,
 		return 0;
 	}
 
-	if (fclose(fp)) {
+	if (lvm_fclose(fp, tc->path_edit))
-		log_sys_error("fclose", tc->path_edit);
+		return_0;
-		return 0;
-	}
 
 	if (rename(temp_file, tc->path_edit)) {
 		log_debug("Renaming %s to %s", temp_file, tc->path_edit);

lib/log/log.c

@@ -17,6 +17,7 @@
 #include "device.h"
 #include "memlock.h"
 #include "lvm-string.h"
+#include "lvm-file.h"
 #include "defaults.h"
 
 #include <stdarg.h>
@@ -121,8 +122,14 @@ void fin_log(void)
 	}
 
 	if (_log_to_file) {
-		if (fclose(_log_file))
+		if (dm_fclose(_log_file)) {
-			fprintf(stderr, "fclose() on log file failed: %s", strerror(errno));
+			if (errno)
+			      fprintf(stderr, "failed to write log file: %s\n",
+				      strerror(errno));
+			else
+			      fprintf(stderr, "failed to write log file\n");
+
+		}
 		_log_to_file = 0;
 	}
 }

lib/misc/lvm-file.c

@@ -321,3 +321,13 @@ void fcntl_unlock_file(int lockfd)
 			  strerror(errno));
 }
 
+int lvm_fclose(FILE *fp, const char *filename)
+{
+	if (!dm_fclose(fp))
+		return 0;
+	if (errno == 0)
+		log_error("%s: write error", filename);
+	else
+		log_sys_error("write error", filename);
+	return EOF;
+}

lib/misc/lvm-file.h

@@ -56,4 +56,13 @@ void fcntl_unlock_file(int lockfd);
   ((buf1).st_ino == (buf2).st_ino && \
    (buf1).st_dev == (buf2).st_dev)
 
+/*
+ * Close the specified stream, taking care to detect and diagnose any write
+ * error.  If there is an error, use the supplied file name in a diagnostic
+ * that is reported via log_error or log_sys_error, as appropriate.
+ * Use this function to close a stream when you've written data to it via
+ * unchecked fprintf, fputc, etc. calls.  Return 0 on success, EOF on failure.
+ */
+int lvm_fclose(FILE *fp, const char *filename);
+
 #endif