do not let git_path clobber errno when reporting errors

Because git_path() calls vsnprintf(), code like

	fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
	die_errno(_("Could not write to '%s'"), git_path("SQUASH_MSG"));

can end up printing an error indicator from vsnprintf() instead of
open() by mistake.  Store the path we are trying to write to in a
temporary variable and pass _that_ to die_errno(), so the messages
written by git cherry-pick/revert and git merge can avoid this source
of confusion.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/merge.c b/builtin/merge.c
index dffd5ec1245865259fd4e72cc304286a1a5b4633..2870a6af6fbc868455f2961483cfbfdb065a1a14 100644 (file)
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -316,13 +316,15 @@ static void squash_message(struct commit *commit)
        struct rev_info rev;
        struct strbuf out = STRBUF_INIT;
        struct commit_list *j;
+       const char *filename;
        int fd;
        struct pretty_print_context ctx = {0};
 
        printf(_("Squash commit -- not updating HEAD\n"));
-       fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
+       filename = git_path("SQUASH_MSG");
+       fd = open(filename, O_WRONLY | O_CREAT, 0666);
        if (fd < 0)
-               die_errno(_("Could not write to '%s'"), git_path("SQUASH_MSG"));
+               die_errno(_("Could not write to '%s'"), filename);
 
        init_revisions(&rev, NULL);
        rev.ignore_merges = 1;
@@ -492,14 +494,16 @@ static void merge_name(const char *remote, struct strbuf *msg)
 
        if (!strcmp(remote, "FETCH_HEAD") &&
                        !access(git_path("FETCH_HEAD"), R_OK)) {
+               const char *filename;
                FILE *fp;
                struct strbuf line = STRBUF_INIT;
                char *ptr;
 
-               fp = fopen(git_path("FETCH_HEAD"), "r");
+               filename = git_path("FETCH_HEAD");
+               fp = fopen(filename, "r");
                if (!fp)
                        die_errno(_("could not open '%s' for reading"),
-                                 git_path("FETCH_HEAD"));
+                                 filename);
                strbuf_getline(&line, fp, '\n');
                fclose(fp);
                ptr = strstr(line.buf, "\tnot-for-merge\t");
@@ -847,20 +851,22 @@ static void add_strategies(const char *string, unsigned attr)
 
 static void write_merge_msg(struct strbuf *msg)
 {
-       int fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
+       const char *filename = git_path("MERGE_MSG");
+       int fd = open(filename, O_WRONLY | O_CREAT, 0666);
        if (fd < 0)
                die_errno(_("Could not open '%s' for writing"),
-                         git_path("MERGE_MSG"));
+                         filename);
        if (write_in_full(fd, msg->buf, msg->len) != msg->len)
-               die_errno(_("Could not write to '%s'"), git_path("MERGE_MSG"));
+               die_errno(_("Could not write to '%s'"), filename);
        close(fd);
 }
 
 static void read_merge_msg(struct strbuf *msg)
 {
+       const char *filename = git_path("MERGE_MSG");
        strbuf_reset(msg);
-       if (strbuf_read_file(msg, git_path("MERGE_MSG"), 0) < 0)
-               die_errno(_("Could not read from '%s'"), git_path("MERGE_MSG"));
+       if (strbuf_read_file(msg, filename, 0) < 0)
+               die_errno(_("Could not read from '%s'"), filename);
 }
 
 static void write_merge_state(void);
@@ -948,13 +954,14 @@ static int finish_automerge(struct commit *head,
 
 static int suggest_conflicts(int renormalizing)
 {
+       const char *filename;
        FILE *fp;
        int pos;
 
-       fp = fopen(git_path("MERGE_MSG"), "a");
+       filename = git_path("MERGE_MSG");
+       fp = fopen(filename, "a");
        if (!fp)
-               die_errno(_("Could not open '%s' for writing"),
-                         git_path("MERGE_MSG"));
+               die_errno(_("Could not open '%s' for writing"), filename);
        fprintf(fp, "\nConflicts:\n");
        for (pos = 0; pos < active_nr; pos++) {
                struct cache_entry *ce = active_cache[pos];
@@ -1046,6 +1053,7 @@ static int setup_with_upstream(const char ***argv)
 
 static void write_merge_state(void)
 {
+       const char *filename;
        int fd;
        struct commit_list *j;
        struct strbuf buf = STRBUF_INIT;
@@ -1053,24 +1061,25 @@ static void write_merge_state(void)
        for (j = remoteheads; j; j = j->next)
                strbuf_addf(&buf, "%s\n",
                        sha1_to_hex(j->item->object.sha1));
-       fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
+       filename = git_path("MERGE_HEAD");
+       fd = open(filename, O_WRONLY | O_CREAT, 0666);
        if (fd < 0)
-               die_errno(_("Could not open '%s' for writing"),
-                         git_path("MERGE_HEAD"));
+               die_errno(_("Could not open '%s' for writing"), filename);
        if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-               die_errno(_("Could not write to '%s'"), git_path("MERGE_HEAD"));
+               die_errno(_("Could not write to '%s'"), filename);
        close(fd);
        strbuf_addch(&merge_msg, '\n');
        write_merge_msg(&merge_msg);
-       fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
+
+       filename = git_path("MERGE_MODE");
+       fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
        if (fd < 0)
-               die_errno(_("Could not open '%s' for writing"),
-                         git_path("MERGE_MODE"));
+               die_errno(_("Could not open '%s' for writing"), filename);
        strbuf_reset(&buf);
        if (!allow_fast_forward)
                strbuf_addf(&buf, "no-ff");
        if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-               die_errno(_("Could not write to '%s'"), git_path("MERGE_MODE"));
+               die_errno(_("Could not write to '%s'"), filename);
        close(fd);
 }
 

diff --git a/builtin/revert.c b/builtin/revert.c
index b61c8e5c52c75be67cda0a41ae0f093252fe4f1a..544e8c3057b2faf120dcfb219c6f8bcc4dec4b0a 100644 (file)
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -288,17 +288,18 @@ static char *get_encoding(const char *message)
 
 static void write_cherry_pick_head(struct commit *commit)
 {
+       const char *filename;
        int fd;
        struct strbuf buf = STRBUF_INIT;
 
        strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 
-       fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
+       filename = git_path("CHERRY_PICK_HEAD");
+       fd = open(filename, O_WRONLY | O_CREAT, 0666);
        if (fd < 0)
-               die_errno(_("Could not open '%s' for writing"),
-                         git_path("CHERRY_PICK_HEAD"));
+               die_errno(_("Could not open '%s' for writing"), filename);
        if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
-               die_errno(_("Could not write to '%s'"), git_path("CHERRY_PICK_HEAD"));
+               die_errno(_("Could not write to '%s'"), filename);
        strbuf_release(&buf);
 }