Use die_errno() instead of die() when checking syscalls

Lots of die() calls did not actually report the kind of error, which
can leave the user confused as to the real problem.  Use die_errno()
where we check a system/library call that sets errno on failure, or
one of the following that wrap such calls:

  Function              Passes on error from
  --------              --------------------
  odb_pack_keep         open
  read_ancestry         fopen
  read_in_full          xread
  strbuf_read           xread
  strbuf_read_file      open or strbuf_read_file
  strbuf_readlink       readlink
  write_in_full         xwrite

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

30 files changed, 79 insertions, 74 deletions

diff --git a/abspath.c b/abspath.c
index 649f34f833..4bee0ba1ec 100644
--- a/abspath.c
+++ b/abspath.c
@@ -41,13 +41,13 @@ const char *make_absolute_path(const char *path)
 
 		if (*buf) {
 			if (!*cwd && !getcwd(cwd, sizeof(cwd)))
-				die ("Could not get current working directory");
+				die_errno ("Could not get current working directory");
 
 			if (chdir(buf))
-				die ("Could not switch to '%s'", buf);
+				die_errno ("Could not switch to '%s'", buf);
 		}
 		if (!getcwd(buf, PATH_MAX))
-			die ("Could not get current working directory");
+			die_errno ("Could not get current working directory");
 
 		if (last_elem) {
 			int len = strlen(buf);
@@ -63,7 +63,7 @@ const char *make_absolute_path(const char *path)
 		if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
 			len = readlink(buf, next_buf, PATH_MAX);
 			if (len < 0)
-				die ("Invalid symlink: %s", buf);
+				die_errno ("Invalid symlink '%s'", buf);
 			if (PATH_MAX <= len)
 				die("symbolic link too long: %s", buf);
 			next_buf[len] = '\0';
@@ -75,7 +75,7 @@ const char *make_absolute_path(const char *path)
 	}
 
 	if (*cwd && chdir(cwd))
-		die ("Could not change back to '%s'", cwd);
+		die_errno ("Could not change back to '%s'", cwd);
 
 	return buf;
 }
@@ -109,7 +109,7 @@ const char *make_nonrelative_path(const char *path)
 	} else {
 		const char *cwd = get_pwd_cwd();
 		if (!cwd)
-			die("Cannot determine the current working directory");
+			die_errno("Cannot determine the current working directory");
 		if (snprintf(buf, PATH_MAX, "%s/%s", cwd, path) >= PATH_MAX)
 			die("Too long path: %.*s", 60, path);
 	}
diff --git a/builtin-add.c b/builtin-add.c
index c1b229a9d8..8f651c137a 100644
--- a/builtin-add.c
+++ b/builtin-add.c
@@ -220,7 +220,7 @@ int edit_patch(int argc, const char **argv, const char *prefix)
 	launch_editor(file, NULL, NULL);
 
 	if (stat(file, &st))
-		die("Could not stat '%s'", file);
+		die_errno("Could not stat '%s'", file);
 	if (!st.st_size)
 		die("Empty patch. Aborted.");
 
diff --git a/builtin-apply.c b/builtin-apply.c
index 6526c087b9..dbc7f2165d 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -2823,8 +2823,8 @@ static void add_index_file(const char *path, unsigned mode, void *buf, unsigned
 	} else {
 		if (!cached) {
 			if (lstat(path, &st) < 0)
-				die("unable to stat newly created file %s",
-				    path);
+				die_errno("unable to stat newly created file '%s'",
+					  path);
 			fill_stat_cache_info(ce, &st);
 		}
 		if (write_sha1_file(buf, size, blob_type, ce->sha1) < 0)
@@ -2913,7 +2913,7 @@ static void create_one_file(char *path, unsigned mode, const char *buf, unsigned
 			++nr;
 		}
 	}
-	die("unable to write file %s mode %o", path, mode);
+	die_errno("unable to write file '%s' mode %o", path, mode);
 }
 
 static void create_file(struct patch *patch)
diff --git a/builtin-archive.c b/builtin-archive.c
index 3c5a5a7822..f9a4bea41e 100644
--- a/builtin-archive.c
+++ b/builtin-archive.c
@@ -13,10 +13,10 @@ 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("could not create archive file: %s ", output_file);
+		die_errno("could not create archive file '%s'", output_file);
 	if (output_fd != 1) {
 		if (dup2(output_fd, 1) < 0)
-			die("could not redirect output");
+			die_errno("could not redirect output");
 		else
 			close(output_fd);
 	}
diff --git a/builtin-blame.c b/builtin-blame.c
index 7d8fbd5919..fd6ca51eeb 100644
--- a/builtin-blame.c
+++ b/builtin-blame.c
@@ -2008,23 +2008,23 @@ static struct commit *fake_working_tree_commit(const char *path, const char *con
 
 		if (contents_from) {
 			if (stat(contents_from, &st) < 0)
-				die("Cannot stat %s", contents_from);
+				die_errno("Cannot stat '%s'", contents_from);
 			read_from = contents_from;
 		}
 		else {
 			if (lstat(path, &st) < 0)
-				die("Cannot lstat %s", path);
+				die_errno("Cannot lstat '%s'", path);
 			read_from = path;
 		}
 		mode = canon_mode(st.st_mode);
 		switch (st.st_mode & S_IFMT) {
 		case S_IFREG:
 			if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)
-				die("cannot open or read %s", read_from);
+				die_errno("cannot open or read '%s'", read_from);
 			break;
 		case S_IFLNK:
 			if (strbuf_readlink(&buf, read_from, st.st_size) < 0)
-				die("cannot readlink %s", read_from);
+				die_errno("cannot readlink '%s'", read_from);
 			break;
 		default:
 			die("unsupported file type %s", read_from);
diff --git a/builtin-clone.c b/builtin-clone.c
index 5f34414ff7..d2b0757e53 100644
--- a/builtin-clone.c
+++ b/builtin-clone.c
@@ -220,13 +220,13 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest)
 
 	dir = opendir(src->buf);
 	if (!dir)
-		die("failed to open %s", src->buf);
+		die_errno("failed to open '%s'", src->buf);
 
 	if (mkdir(dest->buf, 0777)) {
 		if (errno != EEXIST)
-			die("failed to create directory %s", dest->buf);
+			die_errno("failed to create directory '%s'", dest->buf);
 		else if (stat(dest->buf, &buf))
-			die("failed to stat %s", dest->buf);
+			die_errno("failed to stat '%s'", dest->buf);
 		else if (!S_ISDIR(buf.st_mode))
 			die("%s exists and is not a directory", dest->buf);
 	}
@@ -257,11 +257,11 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest)
 			if (!link(src->buf, dest->buf))
 				continue;
 			if (option_local)
-				die("failed to create link %s", dest->buf);
+				die_errno("failed to create link '%s'", dest->buf);
 			option_no_hardlinks = 1;
 		}
 		if (copy_file(dest->buf, src->buf, 0666))
-			die("failed to copy file to %s", dest->buf);
+			die_errno("failed to copy file to '%s'", dest->buf);
 	}
 	closedir(dir);
 }
diff --git a/builtin-commit.c b/builtin-commit.c
index 88c51bdd3a..4bcce06fbf 100644
--- a/builtin-commit.c
+++ b/builtin-commit.c
@@ -434,7 +434,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix)
 		if (isatty(0))
 			fprintf(stderr, "(reading log message from standard input)\n");
 		if (strbuf_read(&sb, 0, 0) < 0)
-			die("could not read log from standard input");
+			die_errno("could not read log from standard input");
 		hook_arg1 = "message";
 	} else if (logfile) {
 		if (strbuf_read_file(&sb, logfile, 0) < 0)
@@ -964,8 +964,9 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	/* Finally, get the commit message */
 	strbuf_reset(&sb);
 	if (strbuf_read_file(&sb, git_path(commit_editmsg), 0) < 0) {
+		int saved_errno = errno;
 		rollback_index_files();
-		die("could not read commit message");
+		die("could not read commit message: %s", strerror(saved_errno));
 	}
 
 	/* Truncate the message just before the diff, if any. */
diff --git a/builtin-fast-export.c b/builtin-fast-export.c
index 333d43894a..9a8a6fc6b1 100644
--- a/builtin-fast-export.c
+++ b/builtin-fast-export.c
@@ -119,7 +119,7 @@ static void handle_object(const unsigned char *sha1)
 
 	printf("blob\nmark :%"PRIu32"\ndata %lu\n", last_idnum, size);
 	if (size && fwrite(buf, size, 1, stdout) != 1)
-		die ("Could not write blob %s", sha1_to_hex(sha1));
+		die_errno ("Could not write blob '%s'", sha1_to_hex(sha1));
 	printf("\n");
 
 	show_progress();
diff --git a/builtin-fmt-merge-msg.c b/builtin-fmt-merge-msg.c
index 1248d5e3a3..9d524000b5 100644
--- a/builtin-fmt-merge-msg.c
+++ b/builtin-fmt-merge-msg.c
@@ -368,7 +368,7 @@ int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 	if (inpath && strcmp(inpath, "-")) {
 		in = fopen(inpath, "r");
 		if (!in)
-			die("cannot open %s", inpath);
+			die_errno("cannot open '%s'", inpath);
 	}
 
 	if (strbuf_read(&input, fileno(in), 0) < 0)
diff --git a/builtin-fsck.c b/builtin-fsck.c
index a49dbe14c7..d0f48cdd2a 100644
--- a/builtin-fsck.c
+++ b/builtin-fsck.c
@@ -217,7 +217,7 @@ static void check_unreachable_object(struct object *obj)
 				return;
 			}
 			if (!(f = fopen(filename, "w")))
-				die("Could not open %s", filename);
+				die_errno("Could not open '%s'", filename);
 			if (obj->type == OBJ_BLOB) {
 				enum object_type type;
 				unsigned long size;
diff --git a/builtin-init-db.c b/builtin-init-db.c
index d1fa12a59e..4a5600631c 100644
--- a/builtin-init-db.c
+++ b/builtin-init-db.c
@@ -61,20 +61,20 @@ static void copy_templates_1(char *path, int baselen,
 		memcpy(template + template_baselen, de->d_name, namelen+1);
 		if (lstat(path, &st_git)) {
 			if (errno != ENOENT)
-				die("cannot stat %s", path);
+				die_errno("cannot stat '%s'", path);
 		}
 		else
 			exists = 1;
 
 		if (lstat(template, &st_template))
-			die("cannot stat template %s", template);
+			die_errno("cannot stat template '%s'", template);
 
 		if (S_ISDIR(st_template.st_mode)) {
 			DIR *subdir = opendir(template);
 			int baselen_sub = baselen + namelen;
 			int template_baselen_sub = template_baselen + namelen;
 			if (!subdir)
-				die("cannot opendir %s", template);
+				die_errno("cannot opendir '%s'", template);
 			path[baselen_sub++] =
 				template[template_baselen_sub++] = '/';
 			path[baselen_sub] =
@@ -91,16 +91,17 @@ static void copy_templates_1(char *path, int baselen,
 			int len;
 			len = readlink(template, lnk, sizeof(lnk));
 			if (len < 0)
-				die("cannot readlink %s", template);
+				die_errno("cannot readlink '%s'", template);
 			if (sizeof(lnk) <= len)
 				die("insanely long symlink %s", template);
 			lnk[len] = 0;
 			if (symlink(lnk, path))
-				die("cannot symlink %s %s", lnk, path);
+				die_errno("cannot symlink '%s' '%s'", lnk, path);
 		}
 		else if (S_ISREG(st_template.st_mode)) {
 			if (copy_file(path, template, st_template.st_mode))
-				die("cannot copy %s to %s", template, path);
+				die_errno("cannot copy '%s' to '%s'", template,
+					  path);
 		}
 		else
 			error("ignoring template %s", template);
@@ -350,7 +351,7 @@ static int guess_repository_type(const char *git_dir)
 	if (!strcmp(".", git_dir))
 		return 1;
 	if (!getcwd(cwd, sizeof(cwd)))
-		die("cannot tell cwd");
+		die_errno("cannot tell cwd");
 	if (!strcmp(git_dir, cwd))
 		return 1;
 	/*
@@ -440,11 +441,11 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 		if (!git_work_tree_cfg) {
 			git_work_tree_cfg = xcalloc(PATH_MAX, 1);
 			if (!getcwd(git_work_tree_cfg, PATH_MAX))
-				die ("Cannot access current working directory.");
+				die_errno ("Cannot access current working directory");
 		}
 		if (access(get_git_work_tree(), X_OK))
-			die ("Cannot access work tree '%s'",
-			     get_git_work_tree());
+			die_errno ("Cannot access work tree '%s'",
+				   get_git_work_tree());
 	}
 
 	set_git_dir(make_absolute_path(git_dir));
diff --git a/builtin-log.c b/builtin-log.c
index 0d34050556..750957cfa9 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -1013,8 +1013,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		if (use_stdout)
 			die("standard output, or directory, which one?");
 		if (mkdir(output_directory, 0777) < 0 && errno != EEXIST)
-			die("Could not create directory %s",
-			    output_directory);
+			die_errno("Could not create directory '%s'",
+				  output_directory);
 	}
 
 	if (rev.pending.nr == 1) {
diff --git a/builtin-mailsplit.c b/builtin-mailsplit.c
index 71f3b3b874..ad5f6b593d 100644
--- a/builtin-mailsplit.c
+++ b/builtin-mailsplit.c
@@ -81,7 +81,7 @@ static int split_one(FILE *mbox, const char *name, int allow_bare)
 
 	fd = open(name, O_WRONLY | O_CREAT | O_EXCL, 0666);
 	if (fd < 0)
-		die("cannot open output file %s", name);
+		die_errno("cannot open output file '%s'", name);
 	output = fdopen(fd, "w");
 
 	/* Copy it out, while searching for a line that begins with
@@ -91,7 +91,7 @@ static int split_one(FILE *mbox, const char *name, int allow_bare)
 		int is_partial = len && buf[len-1] != '\n';
 
 		if (fwrite(buf, 1, len, output) != len)
-			die("cannot write output");
+			die_errno("cannot write output");
 
 		len = read_line_with_nul(buf, sizeof(buf), mbox);
 		if (len == 0) {
@@ -99,7 +99,7 @@ static int split_one(FILE *mbox, const char *name, int allow_bare)
 				status = 1;
 				break;
 			}
-			die("cannot read mbox");
+			die_errno("cannot read mbox");
 		}
 		if (!is_partial && !is_bare && is_from_line(buf, len))
 			break; /* done with one message */
diff --git a/builtin-merge.c b/builtin-merge.c
index 436263bc19..82335b09ed 100644
--- a/builtin-merge.c
+++ b/builtin-merge.c
@@ -268,7 +268,7 @@ static void squash_message(void)
 	printf("Squash commit -- not updating HEAD\n");
 	fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
 	if (fd < 0)
-		die("Could not write to %s", git_path("SQUASH_MSG"));
+		die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
 
 	init_revisions(&rev, NULL);
 	rev.ignore_merges = 1;
@@ -764,7 +764,8 @@ static int suggest_conflicts(void)
 
 	fp = fopen(git_path("MERGE_MSG"), "a");
 	if (!fp)
-		die("Could not open %s for writing", git_path("MERGE_MSG"));
+		die_errno("Could not open '%s' for writing",
+			  git_path("MERGE_MSG"));
 	fprintf(fp, "\nConflicts:\n");
 	for (pos = 0; pos < active_nr; pos++) {
 		struct cache_entry *ce = active_cache[pos];
@@ -1186,27 +1187,29 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 				sha1_to_hex(j->item->object.sha1));
 		fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
 		if (fd < 0)
-			die("Could open %s for writing",
-				git_path("MERGE_HEAD"));
+			die_errno("Could not open '%s' for writing",
+				  git_path("MERGE_HEAD"));
 		if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-			die("Could not write to %s", git_path("MERGE_HEAD"));
+			die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
 		close(fd);
 		strbuf_addch(&merge_msg, '\n');
 		fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
 		if (fd < 0)
-			die("Could open %s for writing", git_path("MERGE_MSG"));
+			die_errno("Could not open '%s' for writing",
+				  git_path("MERGE_MSG"));
 		if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
 			merge_msg.len)
-			die("Could not write to %s", git_path("MERGE_MSG"));
+			die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
 		close(fd);
 		fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
 		if (fd < 0)
-			die("Could open %s for writing", git_path("MERGE_MODE"));
+			die_errno("Could not open '%s' for writing",
+				  git_path("MERGE_MODE"));
 		strbuf_reset(&buf);
 		if (!allow_fast_forward)
 			strbuf_addf(&buf, "no-ff");
 		if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-			die("Could not write to %s", git_path("MERGE_MODE"));
+			die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
 		close(fd);
 	}
 
diff --git a/builtin-rev-parse.c b/builtin-rev-parse.c
index 112d622cda..da26dbc020 100644
--- a/builtin-rev-parse.c
+++ b/builtin-rev-parse.c
@@ -592,7 +592,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 					continue;
 				}
 				if (!getcwd(cwd, PATH_MAX))
-					die("unable to get current working directory");
+					die_errno("unable to get current working directory");
 				printf("%s/.git\n", cwd);
 				continue;
 			}
diff --git a/builtin-revert.c b/builtin-revert.c
index c87115af30..151aa6a981 100644
--- a/builtin-revert.c
+++ b/builtin-revert.c
@@ -135,7 +135,7 @@ static void add_to_msg(const char *string)
 {
 	int len = strlen(string);
 	if (write_in_full(msg_fd, string, len) < 0)
-		die ("Could not write to MERGE_MSG");
+		die_errno ("Could not write to MERGE_MSG");
 }
 
 static void add_message_to_msg(const char *message)
diff --git a/builtin-stripspace.c b/builtin-stripspace.c
index d6e3896c00..1fd2205d53 100644
--- a/builtin-stripspace.c
+++ b/builtin-stripspace.c
@@ -78,7 +78,7 @@ int cmd_stripspace(int argc, const char **argv, const char *prefix)
 		strip_comments = 1;
 
 	if (strbuf_read(&buf, 0, 1024) < 0)
-		die("could not read the input");
+		die_errno("could not read the input");
 
 	stripspace(&buf, strip_comments);
 
diff --git a/builtin-tag.c b/builtin-tag.c
index 7b51095c80..165bec3069 100644
--- a/builtin-tag.c
+++ b/builtin-tag.c
@@ -442,7 +442,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		else {
 			if (!strcmp(msgfile, "-")) {
 				if (strbuf_read(&buf, 0, 1024) < 0)
-					die("cannot read %s", msgfile);
+					die_errno("cannot read '%s'", msgfile);
 			} else {
 				if (strbuf_read_file(&buf, msgfile, 1024) < 0)
 					die_errno("could not open or read '%s'",
diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
index f88e721936..8b3a35e12d 100644
--- a/builtin-tar-tree.c
+++ b/builtin-tar-tree.c
@@ -91,7 +91,7 @@ int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix)
 
 	n = write_in_full(1, content + 11, 41);
 	if (n < 41)
-		die("git get-tar-commit-id: write error");
+		die_errno("git get-tar-commit-id: write error");
 
 	return 0;
 }
diff --git a/combine-diff.c b/combine-diff.c
index 60d03676bb..bbf74fc42e 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -746,7 +746,7 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 
 			done = read_in_full(fd, result, len);
 			if (done < 0)
-				die("read error '%s'", elem->path);
+				die_errno("read error '%s'", elem->path);
 			else if (done < len)
 				die("early EOF '%s'", elem->path);
 
diff --git a/diff.c b/diff.c
index 48043f5bdb..aec613f85a 100644
--- a/diff.c
+++ b/diff.c
@@ -1982,7 +1982,7 @@ static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
 		size = buf.len;
 	}
 	if (write_in_full(fd, blob, size) != size)
-		die("unable to write temp-file");
+		die_errno("unable to write temp-file");
 	close(fd);
 	temp->name = temp->tmp_path;
 	strcpy(temp->hex, sha1_to_hex(sha1));
@@ -2026,7 +2026,7 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 		if (S_ISLNK(st.st_mode)) {
 			struct strbuf sb = STRBUF_INIT;
 			if (strbuf_readlink(&sb, name, st.st_size) < 0)
-				die("readlink(%s)", name);
+				die_errno("readlink(%s)", name);
 			prep_temp_blob(name, temp, sb.buf, sb.len,
 				       (one->sha1_valid ?
 					one->sha1 : null_sha1),
@@ -2219,7 +2219,7 @@ static void diff_fill_sha1_info(struct diff_filespec *one)
 				return;
 			}
 			if (lstat(one->path, &st) < 0)
-				die("stat %s", one->path);
+				die_errno("stat '%s'", one->path);
 			if (index_path(one->sha1, one->path, &st, 0))
 				die("cannot hash %s", one->path);
 		}
diff --git a/entry.c b/entry.c
index 8ec880bdbd..d3e86c722a 100644
--- a/entry.c
+++ b/entry.c
@@ -37,7 +37,7 @@ static void create_directories(const char *path, int path_len,
 			if (errno == EEXIST && state->force &&
 			    !unlink_or_warn(buf) && !mkdir(buf, 0777))
 				continue;
-			die("cannot create directory at %s", buf);
+			die_errno("cannot create directory at '%s'", buf);
 		}
 	}
 	free(buf);
diff --git a/fast-import.c b/fast-import.c
index d31a4e8217..7ef9865aa6 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -905,10 +905,10 @@ static char *keep_pack(char *curr_index_name)
 
 	keep_fd = odb_pack_keep(name, sizeof(name), pack_data->sha1);
 	if (keep_fd < 0)
-		die("cannot create keep file");
+		die_errno("cannot create keep file");
 	write_or_die(keep_fd, keep_msg, strlen(keep_msg));
 	if (close(keep_fd))
-		die("failed to write keep file");
+		die_errno("failed to write keep file");
 
 	snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 		 get_object_directory(), sha1_to_hex(pack_data->sha1));
diff --git a/hash-object.c b/hash-object.c
index 47cf43c3cd..9455dd0709 100644
--- a/hash-object.c
+++ b/hash-object.c
@@ -29,7 +29,7 @@ static void hash_object(const char *path, const char *type, int write_object,
 	int fd;
 	fd = open(path, O_RDONLY);
 	if (fd < 0)
-		die("Cannot open %s", path);
+		die_errno("Cannot open '%s'", path);
 	hash_fd(fd, type, write_object, vpath);
 }
 
diff --git a/ll-merge.c b/ll-merge.c
index 81c02ad053..caf22be927 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -152,7 +152,7 @@ static void create_temp(mmfile_t *src, char *path)
 	strcpy(path, ".merge_file_XXXXXX");
 	fd = xmkstemp(path);
 	if (write_in_full(fd, src->ptr, src->size) != src->size)
-		die("unable to write temp-file");
+		die_errno("unable to write temp-file");
 	close(fd);
 }
 
diff --git a/mktag.c b/mktag.c
index 99a356e9ee..a609e3ebd1 100644
--- a/mktag.c
+++ b/mktag.c
@@ -165,7 +165,7 @@ int main(int argc, char **argv)
 	setup_git_directory();
 
 	if (strbuf_read(&buf, 0, 4096) < 0) {
-		die("could not read from stdin");
+		die_errno("could not read from stdin");
 	}
 
 	/* Verify it for some basic sanity: it needs to start with
diff --git a/read-cache.c b/read-cache.c
index f76b5bb2e1..4e3e272ee4 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1265,7 +1265,7 @@ int read_index_from(struct index_state *istate, const char *path)
 	mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 	close(fd);
 	if (mmap == MAP_FAILED)
-		die("unable to map index file");
+		die_errno("unable to map index file");
 
 	hdr = mmap;
 	if (verify_hdr(hdr, mmap_size) < 0)
diff --git a/setup.c b/setup.c
index 4d27f28c8f..e3781b656d 100644
--- a/setup.c
+++ b/setup.c
@@ -327,7 +327,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 				return NULL;
 			set_git_dir(make_absolute_path(gitdirenv));
 			if (chdir(work_tree_env) < 0)
-				die ("Could not chdir to %s", work_tree_env);
+				die_errno ("Could not chdir to '%s'", work_tree_env);
 			strcat(buffer, "/");
 			return retval;
 		}
@@ -339,7 +339,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 	}
 
 	if (!getcwd(cwd, sizeof(cwd)-1))
-		die("Unable to read current working directory");
+		die_errno("Unable to read current working directory");
 
 	ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
 	if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
@@ -382,7 +382,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 		if (offset <= ceil_offset) {
 			if (nongit_ok) {
 				if (chdir(cwd))
-					die("Cannot come back to cwd");
+					die_errno("Cannot come back to cwd");
 				*nongit_ok = 1;
 				return NULL;
 			}
@@ -493,10 +493,10 @@ const char *setup_git_directory(void)
 		static char buffer[PATH_MAX + 1];
 		char *rel;
 		if (retval && chdir(retval))
-			die ("Could not jump back into original cwd");
+			die_errno ("Could not jump back into original cwd");
 		rel = get_relative_cwd(buffer, PATH_MAX, get_git_work_tree());
 		if (rel && *rel && chdir(get_git_work_tree()))
-			die ("Could not jump to working directory");
+			die_errno ("Could not jump to working directory");
 		return rel && *rel ? strcat(rel, "/") : NULL;
 	}
 
diff --git a/transport.c b/transport.c
index 17891d5149..8decd663f1 100644
--- a/transport.c
+++ b/transport.c
@@ -158,7 +158,7 @@ static struct ref *get_refs_via_rsync(struct transport *transport, int for_push)
 
 	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
 	if (!mkdtemp(temp_dir.buf))
-		die ("Could not make temporary directory");
+		die_errno ("Could not make temporary directory");
 	temp_dir_len = temp_dir.len;
 
 	strbuf_addstr(&buf, rsync_url(transport->url));
@@ -321,7 +321,7 @@ static int rsync_transport_push(struct transport *transport,
 
 	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
 	if (!mkdtemp(temp_dir.buf))
-		die ("Could not make temporary directory");
+		die_errno ("Could not make temporary directory");
 	strbuf_addch(&temp_dir, '/');
 
 	if (flags & TRANSPORT_PUSH_ALL) {
diff --git a/unpack-file.c b/unpack-file.c
index 75cd2f1a6a..ac9cbf7cd8 100644
--- a/unpack-file.c
+++ b/unpack-file.c
@@ -17,7 +17,7 @@ static char *create_temp_file(unsigned char *sha1)
 	strcpy(path, ".merge_file_XXXXXX");
 	fd = xmkstemp(path);
 	if (write_in_full(fd, buf, size) != size)
-		die("unable to write temp-file");
+		die_errno("unable to write temp-file");
 	close(fd);
 	return path;
 }