From 8d72ffe268305a823057053f6a172ac7debee3b0 Mon Sep 17 00:00:00 2001
From: Gediminas Jakutis <gediminas@varciai.lt>
Date: Sat, 15 Feb 2020 21:10:46 +0200
Subject: add a wrapper for closing files.

Signed-off-by: Gediminas Jakutis <gediminas@varciai.lt>
---
 src/io.c   | 36 ++++++++++++++++++++++++++++++++----
 src/io.h   |  3 ++-
 src/main.c |  9 ++++-----
 3 files changed, 38 insertions(+), 10 deletions(-)

(limited to 'src')

diff --git a/src/io.c b/src/io.c
index 74ea274..142e230 100644
--- a/src/io.c
+++ b/src/io.c
@@ -1,5 +1,6 @@
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <linux/limits.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
@@ -9,16 +10,14 @@
 #include <libgen.h>
 #include "io.h"
 
-int openstream(struct stream *in)
+int stream_open(struct stream *in)
 {
 	struct stat st;
 	mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP;
 	char *dname = NULL;
 	int ret = 0;
 
-	in->fd = -1;
-
-	if (!in->name) {
+	if (!in || in->fd > 0 || !in->name) {
 		ret = EINVAL;
 		goto err;
 	}
@@ -89,3 +88,32 @@ err:
 	free(dname);
 	return ret;
 }
+
+int stream_close(struct stream *in)
+{
+	char path[PATH_MAX];
+	int ret = 0;
+
+	if (!in || in->fd < 0) {
+		ret = EINVAL;
+		goto early_err;
+	}
+
+	if (in->out && in->name) {
+		snprintf(path, PATH_MAX, "/proc/self/fd/%i", in->fd);
+		if (linkat(AT_FDCWD, path, AT_FDCWD, in->name, AT_SYMLINK_FOLLOW)) {
+			ret = errno;
+			/* TODO: error message */
+			goto err;
+		}
+	} else {
+		ret = EINVAL;
+		goto err;
+	}
+
+err:
+	close(in->fd);
+	in->fd = -1;
+early_err:
+	return ret;
+}
diff --git a/src/io.h b/src/io.h
index efc3f94..79216f2 100644
--- a/src/io.h
+++ b/src/io.h
@@ -11,6 +11,7 @@ struct stream {
 	char *name;
 };
 
-int openstream(struct stream *in);
+int stream_open(struct stream *in);
+int stream_close(struct stream *in);
 
 #endif /* ALGOS_IO_H_INCLUDED */
diff --git a/src/main.c b/src/main.c
index 7cc0c5e..2e1ffe1 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,4 +1,3 @@
-#include <unistd.h>
 #include <errno.h>
 #include <stddef.h>
 #include <stdlib.h>
@@ -31,7 +30,7 @@ int main(int argc, char **argv)
 	file_in.name = settings.filein;
 	file_in.stride = 0; /* TODO */
 
-	if ((ret = openstream(&file_in))) {
+	if ((ret = stream_open(&file_in))) {
 		goto out;
 	}
 
@@ -40,13 +39,13 @@ int main(int argc, char **argv)
 	file_out.n = file_in.n;
 	file_out.stride = 0; /* TODO */
 
-	if ((ret = openstream(&file_out))) {
+	if ((ret = stream_open(&file_out))) {
 		goto out;
 	}
 
 out:
-	close(file_in.fd);
-	close(file_out.fd);
+	stream_close(&file_in);
+	stream_close(&file_out);
 	return ret;
 }
 
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