use xopen() to handle fatal open(2) failures

Add and apply a semantic patch for using xopen() instead of calling
open(2) and die() or die_errno() explicitly.  This makes the error
messages more consistent and shortens the code.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/add.c

@@ -313,9 +313,7 @@ static int edit_patch(int argc, const char **argv, const char *prefix)
 	rev.diffopt.output_format = DIFF_FORMAT_PATCH;
 	rev.diffopt.use_color = 0;
 	rev.diffopt.flags.ignore_dirty_submodules = 1;
-	out = open(file, O_CREAT | O_WRONLY | O_TRUNC, 0666);
-	if (out < 0)
-		die(_("Could not open '%s' for writing."), file);
+	out = xopen(file, O_CREAT | O_WRONLY | O_TRUNC, 0666);
 	rev.diffopt.file = xfdopen(out, "w");
 	rev.diffopt.close_file = 1;
 	if (run_diff_files(&rev, 0))

builtin/archive.c

@@ -12,9 +12,7 @@
 
 static void create_output_file(const char *output_file)
 {
-	int output_fd = open(output_file, O_CREAT | O_WRONLY | O_TRUNC, 0666);
-	if (output_fd < 0)
-		die_errno(_("could not create archive file '%s'"), output_file);
+	int output_fd = xopen(output_file, O_CREAT | O_WRONLY | O_TRUNC, 0666);
 	if (output_fd != 1) {
 		if (dup2(output_fd, 1) < 0)
 			die_errno(_("could not redirect output"));

builtin/bugreport.c

@@ -171,10 +171,7 @@ int cmd_bugreport(int argc, const char **argv, const char *prefix)
 	get_populated_hooks(&buffer, !startup_info->have_repository);
 
 	/* fopen doesn't offer us an O_EXCL alternative, except with glibc. */
-	report = open(report_path.buf, O_CREAT | O_EXCL | O_WRONLY, 0666);
-
-	if (report < 0)
-		die(_("couldn't create a new file at '%s'"), report_path.buf);
+	report = xopen(report_path.buf, O_CREAT | O_EXCL | O_WRONLY, 0666);
 
 	if (write_in_full(report, buffer.buf, buffer.len) < 0)
 		die_errno(_("unable to write to %s"), report_path.buf);

builtin/commit-tree.c

@@ -88,9 +88,7 @@ static int parse_file_arg_callback(const struct option *opt,
 	if (!strcmp(arg, "-"))
 		fd = 0;
 	else {
-		fd = open(arg, O_RDONLY);
-		if (fd < 0)
-			die_errno(_("git commit-tree: failed to open '%s'"), arg);
+		fd = xopen(arg, O_RDONLY);
 	}
 	if (strbuf_read(buf, fd, 0) < 0)
 		die_errno(_("git commit-tree: failed to read '%s'"), arg);

builtin/hash-object.c

@@ -53,9 +53,7 @@ static void hash_object(const char *path, const char *type, const char *vpath,
 			unsigned flags, int literally)
 {
 	int fd;
-	fd = open(path, O_RDONLY);
-	if (fd < 0)
-		die_errno("Cannot open '%s'", path);
+	fd = xopen(path, O_RDONLY);
 	hash_fd(fd, type, vpath, flags, literally);
 }
 

builtin/index-pack.c

@@ -338,15 +338,11 @@ static const char *open_pack_file(const char *pack_name)
 						"pack/tmp_pack_XXXXXX");
 			pack_name = strbuf_detach(&tmp_file, NULL);
 		} else {
-			output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
-			if (output_fd < 0)
-				die_errno(_("unable to create '%s'"), pack_name);
+			output_fd = xopen(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 		}
 		nothread_data.pack_fd = output_fd;
 	} else {
-		input_fd = open(pack_name, O_RDONLY);
-		if (input_fd < 0)
-			die_errno(_("cannot open packfile '%s'"), pack_name);
+		input_fd = xopen(pack_name, O_RDONLY);
 		output_fd = -1;
 		nothread_data.pack_fd = input_fd;
 	}

builtin/mailsplit.c

@@ -75,9 +75,7 @@ static int split_one(FILE *mbox, const char *name, int allow_bare)
 		fprintf(stderr, "corrupt mailbox\n");
 		exit(1);
 	}
-	fd = open(name, O_WRONLY | O_CREAT | O_EXCL, 0666);
-	if (fd < 0)
-		die_errno("cannot open output file '%s'", name);
+	fd = xopen(name, O_WRONLY | O_CREAT | O_EXCL, 0666);
 	output = xfdopen(fd, "w");
 
 	/* Copy it out, while searching for a line that begins with

builtin/merge.c

@@ -1136,9 +1136,7 @@ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge
 		merge_names = &fetch_head_file;
 
 	filename = git_path_fetch_head(the_repository);
-	fd = open(filename, O_RDONLY);
-	if (fd < 0)
-		die_errno(_("could not open '%s' for reading"), filename);
+	fd = xopen(filename, O_RDONLY);
 
 	if (strbuf_read(merge_names, fd, 0) < 0)
 		die_errno(_("could not read '%s'"), filename);

builtin/notes.c

@@ -172,9 +172,7 @@ static void prepare_note_data(const struct object_id *object, struct note_data *
 
 		/* write the template message before editing: */
 		d->edit_path = git_pathdup("NOTES_EDITMSG");
-		fd = open(d->edit_path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
-		if (fd < 0)
-			die_errno(_("could not create file '%s'"), d->edit_path);
+		fd = xopen(d->edit_path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
 
 		if (d->given)
 			write_or_die(fd, d->buf.buf, d->buf.len);

builtin/tag.c

@@ -293,9 +293,7 @@ static void create_tag(const struct object_id *object, const char *object_ref,
 
 		/* write the template message before editing: */
 		path = git_pathdup("TAG_EDITMSG");
-		fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
-		if (fd < 0)
-			die_errno(_("could not create file '%s'"), path);
+		fd = xopen(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
 
 		if (opt->message_given) {
 			write_or_die(fd, buf->buf, buf->len);

builtin/update-index.c

@@ -95,9 +95,7 @@ static int create_file(const char *path)
 {
 	int fd;
 	path = get_mtime_path(path);
-	fd = open(path, O_CREAT | O_RDWR, 0644);
-	if (fd < 0)
-		die_errno(_("failed to create file %s"), path);
+	fd = xopen(path, O_CREAT | O_RDWR, 0644);
 	return fd;
 }
 

contrib/coccinelle/xopen.cocci

@@ -0,0 +1,16 @@
+@@
+identifier fd;
+identifier die_fn =~ "^(die|die_errno)$";
+@@
+(
+  fd =
+- open
++ xopen
+  (...);
+|
+  int fd =
+- open
++ xopen
+  (...);
+)
+- if ( \( fd < 0 \| fd == -1 \) ) { die_fn(...); }

csum-file.c

@@ -131,12 +131,8 @@ struct hashfile *hashfd_check(const char *name)
 	int sink, check;
 	struct hashfile *f;
 
-	sink = open("/dev/null", O_WRONLY);
-	if (sink < 0)
-		die_errno("unable to open /dev/null");
-	check = open(name, O_RDONLY);
-	if (check < 0)
-		die_errno("unable to open '%s'", name);
+	sink = xopen("/dev/null", O_WRONLY);
+	check = xopen(name, O_RDONLY);
 	f = hashfd(sink, name);
 	f->check_fd = check;
 	f->check_buffer = xmalloc(f->buffer_len);

pack-write.c

@@ -75,9 +75,7 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
 			index_name = strbuf_detach(&tmp_file, NULL);
 		} else {
 			unlink(index_name);
-			fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
-			if (fd < 0)
-				die_errno("unable to create '%s'", index_name);
+			fd = xopen(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
 		}
 		f = hashfd(fd, index_name);
 	}
@@ -256,9 +254,7 @@ const char *write_rev_file_order(const char *rev_name,
 			rev_name = strbuf_detach(&tmp_file, NULL);
 		} else {
 			unlink(rev_name);
-			fd = open(rev_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
-			if (fd < 0)
-				die_errno("unable to create '%s'", rev_name);
+			fd = xopen(rev_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
 		}
 		f = hashfd(fd, rev_name);
 	} else if (flags & WRITE_REV_VERIFY) {

run-command.c

@@ -761,9 +761,7 @@ fail_pipe:
 		notify_pipe[0] = notify_pipe[1] = -1;
 
 	if (cmd->no_stdin || cmd->no_stdout || cmd->no_stderr) {
-		null_fd = open("/dev/null", O_RDWR | O_CLOEXEC);
-		if (null_fd < 0)
-			die_errno(_("open /dev/null failed"));
+		null_fd = xopen("/dev/null", O_RDWR | O_CLOEXEC);
 		set_cloexec(null_fd);
 	}