Modify the inotify implementation so that inotify watches are

only created after dnsmasq has changed permissions and userid.
This means that the permissions used when creating the watches
are the same as used for accessing watched files, which makes
more sense and avoids odd and confusing error conditions.
This commit is contained in:
Simon Kelley committed 2026-02-28 21:30:57 +00:00
1 parent 66d9658f5f
commit 65adc53130
4 files changed
+65 -19

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+25 -10
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@@ -40,7 +40,7 @@ static char *inotify_buffer;
points to, made absolute if relative.
If path doesn't exist or is not a symlink, return NULL.
Return value is malloc'ed */
static char *my_readlink(char *path)
static char *my_readlink(int errfd, char *path)
{
ssize_t rc, size = 64;
char *buf;
@@ -59,7 +59,10 @@ static char *my_readlink(char *path)
return NULL;
}
else
die(_("cannot access path %s: %s"), path, EC_MISC);
{
send_event(errfd, EVENT_LINK_ERR, errno, path);
_exit(0);
}
}
else if (rc < size-1)
{
@@ -85,15 +88,18 @@ static char *my_readlink(char *path)
}
}
void inotify_dnsmasq_init()
void inotify_dnsmasq_init(int errfd)
{
struct resolvc *res;
inotify_buffer = safe_malloc(INOTIFY_SZ);
daemon->inotifyfd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
if (daemon->inotifyfd == -1)
die(_("failed to create inotify: %s"), NULL, EC_MISC);
{
send_event(errfd, EVENT_INOTFY_ERR, errno, NULL);
_exit(0);
}
if (daemon->port == 0 || option_bool(OPT_NO_RESOLV))
return;
@@ -105,10 +111,13 @@ void inotify_dnsmasq_init()
strcpy(path, res->name);
/* Follow symlinks until we reach a non-symlink, or a non-existent file. */
while ((new_path = my_readlink(path)))
while ((new_path = my_readlink(errfd, path)))
{
if (links-- == 0)
die(_("too many symlinks following %s"), res->name, EC_MISC);
{
send_event(errfd, EVENT_TMSL_ERR, 0, res->name);
_exit(0);
}
free(path);
path = new_path;
}
@@ -124,12 +133,18 @@ void inotify_dnsmasq_init()
*d = '/';
if (res->wd == -1 && errno == ENOENT)
die(_("directory %s for resolv-file is missing, cannot poll"), res->name, EC_MISC);
{
send_event(errfd, EVENT_RESOLV_ERR, 0, res->name);
_exit(0);
}
}
if (res->wd == -1)
die(_("failed to create inotify for %s: %s"), res->name, EC_MISC);
{
send_event(errfd, EVENT_IFILE_ERR, errno, res->name);
_exit(0);
}
}
}