use xstrfmt in favor of manual size calculations

In many parts of the code, we do an ugly and error-prone
malloc like:

const char *fmt = "something %s";
buf = xmalloc(strlen(foo) + 10 + 1);
sprintf(buf, fmt, foo);

This makes the code brittle, and if we ever get the
allocation wrong, is a potential heap overflow. Let's
instead favor xstrfmt, which handles the allocation
automatically, and makes the code shorter and more readable.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/remote.c b/remote.c
index 0e9459cc0675d2f232b1c1fda62080d04aa88ec5..bf27e44762d35c61a23e664f485ebcea0e935d3f 100644 (file)
--- a/remote.c
+++ b/remote.c
@@ -170,7 +170,6 @@ static struct branch *make_branch(const char *name, int len)
 {
        struct branch *ret;
        int i;
-       char *refname;
 
        for (i = 0; i < branches_nr; i++) {
                if (len ? (!strncmp(name, branches[i]->name, len) &&
@@ -186,10 +185,7 @@ static struct branch *make_branch(const char *name, int len)
                ret->name = xstrndup(name, len);
        else
                ret->name = xstrdup(name);
-       refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
-       strcpy(refname, "refs/heads/");
-       strcpy(refname + strlen("refs/heads/"), ret->name);
-       ret->refname = refname;
+       ret->refname = xstrfmt("refs/heads/%s", ret->name);
 
        return ret;
 }

diff --git a/unpack-trees.c b/unpack-trees.c
index 97fc9954672f2c374541cad827bb5c459abebcdc..c237370b1f705e2e4aa4b51b8635dd50e7b8d013 100644 (file)
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -56,17 +56,15 @@ void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
        int i;
        const char **msgs = opts->msgs;
        const char *msg;
-       char *tmp;
        const char *cmd2 = strcmp(cmd, "checkout") ? cmd : "switch branches";
+
        if (advice_commit_before_merge)
                msg = "Your local changes to the following files would be overwritten by %s:\n%%s"
                        "Please, commit your changes or stash them before you can %s.";
        else
                msg = "Your local changes to the following files would be overwritten by %s:\n%%s";
-       tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen(cmd2) - 2);
-       sprintf(tmp, msg, cmd, cmd2);
-       msgs[ERROR_WOULD_OVERWRITE] = tmp;
-       msgs[ERROR_NOT_UPTODATE_FILE] = tmp;
+       msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
+               xstrfmt(msg, cmd, cmd2);
 
        msgs[ERROR_NOT_UPTODATE_DIR] =
                "Updating the following directories would lose untracked files in it:\n%s";
@@ -76,12 +74,9 @@ void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
                        "Please move or remove them before you can %s.";
        else
                msg = "The following untracked working tree files would be %s by %s:\n%%s";
-       tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen("removed") + strlen(cmd2) - 4);
-       sprintf(tmp, msg, "removed", cmd, cmd2);
-       msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = tmp;
-       tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen("overwritten") + strlen(cmd2) - 4);
-       sprintf(tmp, msg, "overwritten", cmd, cmd2);
-       msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = tmp;
+
+       msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, "removed", cmd, cmd2);
+       msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, "overwritten", cmd, cmd2);
 
        /*
         * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we