On Wed, Jan 31, 2018 at 02:59:32PM -0800, Junio C Hamano wrote:
> Eric Sunshine <sunshine@xxxxxxxxxxxxxx> writes:
>
> > On Wed, Jan 31, 2018 at 4:30 AM, Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx> wrote:
> >> Pointing the user to $GIT_DIR/rebase-apply may encourage them to mess
> >> around in there, which is not a good thing. With this, the user does
> >> not have to keep the path around somewhere (because after a couple of
> >> commands, the path may be out of scrollback buffer) when they need to
> >> look at the patch.
> >>
> >> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
> >> ---
> >> diff --git a/builtin/am.c b/builtin/am.c
> >> @@ -2121,6 +2120,22 @@ static void am_abort(struct am_state *state)
> >> +static int show_patch(struct am_state *state)
> >> +{
> >> + struct strbuf sb = STRBUF_INIT;
> >> + int len;
> >> +
> >> + len = strbuf_read_file(&sb, am_path(state, msgnum(state)), 0);
> >> + if (len < 0)
> >> + die_errno(_("failed to read '%s'"),
> >> + am_path(state, msgnum(state)));
> >
> > Isn't this am_path() invocation inside die_errno() likely to clobber
> > the 'errno' from strbuf_read_file() which you want to be reporting?
>
> True.
Thanks both. Good catch. Of course I will fix this in the re-roll, but
should we also do something for the current code base with the
following patch?
I think this is something coccinelle can help catch, but my
coccinelle-foo is way too low to come up with something like
"die_errno() must not take any arguments as function calls, except _()
and N_()".
-- 8< --
Subject: [PATCH] Preserve errno in case case before calling sth_errno()
All these locations do something like this
sth_errno(..., somefunc(...));
where somefunc() can potentially change errno, which will be read by
sth_errno(). Call somefunc separately with errno preserved to avoid
this.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
builtin/am.c | 8 +++++++-
builtin/commit.c | 8 ++++++--
builtin/init-db.c | 9 ++++++---
rerere.c | 9 ++++++---
shallow.c | 27 ++++++++++++++++++---------
5 files changed, 43 insertions(+), 18 deletions(-)
diff --git a/builtin/am.c b/builtin/am.c
index acfe9d3c8c..ba67e187a4 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -244,6 +244,9 @@ static int am_in_progress(const struct am_state *state)
static int read_state_file(struct strbuf *sb, const struct am_state *state,
const char *file, int trim)
{
+ int saved_errno;
+ const char *path;
+
strbuf_reset(sb);
if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
@@ -256,7 +259,10 @@ static int read_state_file(struct strbuf *sb, const struct am_state *state,
if (errno == ENOENT)
return -1;
- die_errno(_("could not read '%s'"), am_path(state, file));
+ saved_errno = errno;
+ path = am_path(state, file);
+ errno = saved_errno;
+ die_errno(_("could not read '%s'"), path);
}
/**
diff --git a/builtin/commit.c b/builtin/commit.c
index 4610e3d8e3..39836b3734 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -780,8 +780,12 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
}
s->fp = fopen_for_writing(git_path_commit_editmsg());
- if (s->fp == NULL)
- die_errno(_("could not open '%s'"), git_path_commit_editmsg());
+ if (s->fp == NULL) {
+ int saved_errno = errno;
+ const char *path = git_path_commit_editmsg();
+ errno = saved_errno;
+ die_errno(_("could not open '%s'"), path);
+ }
/* Ignore status.displayCommentPrefix: we do need comments in COMMIT_EDITMSG. */
old_display_comment_prefix = s->display_comment_prefix;
diff --git a/builtin/init-db.c b/builtin/init-db.c
index c9b7946bad..e384749f73 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -570,9 +570,12 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
set_git_work_tree(work_tree);
else
set_git_work_tree(git_work_tree_cfg);
- if (access(get_git_work_tree(), X_OK))
- die_errno (_("Cannot access work tree '%s'"),
- get_git_work_tree());
+ if (access(get_git_work_tree(), X_OK)) {
+ int saved_errno = errno;
+ const char *path = get_git_work_tree();
+ errno = saved_errno;
+ die_errno(_("Cannot access work tree '%s'"), path);
+ }
}
else {
if (work_tree)
diff --git a/rerere.c b/rerere.c
index 1ce440f4bb..f19a53ff2c 100644
--- a/rerere.c
+++ b/rerere.c
@@ -683,9 +683,12 @@ static int merge(const struct rerere_id *id, const char *path)
* A successful replay of recorded resolution.
* Mark that "postimage" was used to help gc.
*/
- if (utime(rerere_path(id, "postimage"), NULL) < 0)
- warning_errno("failed utime() on %s",
- rerere_path(id, "postimage"));
+ if (utime(rerere_path(id, "postimage"), NULL) < 0) {
+ int saved_errno = errno;
+ const char *path = rerere_path(id, "postimage");
+ errno = saved_errno;
+ warning_errno("failed utime() on %s", path);
+ }
/* Update "path" with the resolution */
f = fopen(path, "w");
diff --git a/shallow.c b/shallow.c
index df4d44ea7a..9da82f5292 100644
--- a/shallow.c
+++ b/shallow.c
@@ -295,9 +295,12 @@ const char *setup_temporary_shallow(const struct oid_array *extra)
temp = xmks_tempfile(git_path("shallow_XXXXXX"));
if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
- close_tempfile_gently(temp) < 0)
- die_errno("failed to write to %s",
- get_tempfile_path(temp));
+ close_tempfile_gently(temp) < 0) {
+ int saved_errno = errno;
+ const char *path = get_tempfile_path(temp);
+ errno = saved_errno;
+ die_errno("failed to write to %s", path);
+ }
strbuf_release(&sb);
return get_tempfile_path(temp);
}
@@ -319,9 +322,12 @@ void setup_alternate_shallow(struct lock_file *shallow_lock,
LOCK_DIE_ON_ERROR);
check_shallow_file_for_update();
if (write_shallow_commits(&sb, 0, extra)) {
- if (write_in_full(fd, sb.buf, sb.len) < 0)
- die_errno("failed to write to %s",
- get_lock_file_path(shallow_lock));
+ if (write_in_full(fd, sb.buf, sb.len) < 0) {
+ int saved_errno = errno;
+ const char *path = get_lock_file_path(shallow_lock);
+ errno = saved_errno;
+ die_errno("failed to write to %s", path);
+ }
*alternate_shallow_file = get_lock_file_path(shallow_lock);
} else
/*
@@ -366,9 +372,12 @@ void prune_shallow(int show_only)
LOCK_DIE_ON_ERROR);
check_shallow_file_for_update();
if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
- if (write_in_full(fd, sb.buf, sb.len) < 0)
- die_errno("failed to write to %s",
- get_lock_file_path(&shallow_lock));
+ if (write_in_full(fd, sb.buf, sb.len) < 0) {
+ int saved_errno = errno;
+ const char *path = get_lock_file_path(&shallow_lock);
+ errno = saved_errno;
+ die_errno("failed to write to %s", path);
+ }
commit_lock_file(&shallow_lock);
} else {
unlink(git_path_shallow());
--
2.16.1.205.g271f633410
-- 8< --
