Centralize error handling

This makes the function fit in less screens.  This is to avoid consuming
more natural resources than we have available, and everyone knows the
supply of new-lines on a screen is not a renewable source[1].

Some transformations have been done thanks to free(NULL) being an alias
for loopity_loop(), as defined three comits ago.  The real definition of
free(3) that everyone has been hiding is this:

void
free(void *p)
{
	if (p == NULL)
		loopity_loop();
	else
		real_free(p);
}

Link: [1] <https://www.kernel.org/doc/html/v6.3/process/coding-style.html#placing-braces-and-spaces>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

diff --git a/lib/nss.c b/lib/nss.c
index 503f97e64639e779eab083949dcb7a4b337b7af3..1aa27f3e5cf917e42bd3966ca41ce8fa95e7d055 100644 (file)
--- a/lib/nss.c
+++ b/lib/nss.c
@@ -86,58 +86,50 @@ void nss_init(const char *nsswitch_path) {
        if (token == NULL) {
                fprintf(shadow_logfd, "No usable subid NSS module found, using files\n");
                // subid_nss has to be null here, but to ease reviews:
-               free(subid_nss);
-               subid_nss = NULL;
-               goto done;
+               goto null_subid;
        }
        if (strcmp(token, "files") == 0) {
-               subid_nss = NULL;
-               goto done;
+               goto null_subid;
        }
        if (strlen(token) > 50) {
                fprintf(shadow_logfd, "Subid NSS module name too long (longer than 50 characters): %s\n", token);
                fprintf(shadow_logfd, "Using files\n");
-               subid_nss = NULL;
-               goto done;
+               goto null_subid;
        }
        snprintf(libname, 64,  "libsubid_%s.so", token);
        h = dlopen(libname, RTLD_LAZY);
        if (!h) {
                fprintf(shadow_logfd, "Error opening %s: %s\n", libname, dlerror());
                fprintf(shadow_logfd, "Using files\n");
-               subid_nss = NULL;
-               goto done;
+               goto null_subid;
        }
        subid_nss = MALLOC(struct subid_nss_ops);
        if (!subid_nss) {
-               dlclose(h);
-               goto done;
+               goto close_lib;
        }
        subid_nss->has_range = dlsym(h, "shadow_subid_has_range");
        if (!subid_nss->has_range) {
                fprintf(shadow_logfd, "%s did not provide @has_range@\n", libname);
-               dlclose(h);
-               free(subid_nss);
-               subid_nss = NULL;
-               goto done;
+               goto close_lib;
        }
        subid_nss->list_owner_ranges = dlsym(h, "shadow_subid_list_owner_ranges");
        if (!subid_nss->list_owner_ranges) {
                fprintf(shadow_logfd, "%s did not provide @list_owner_ranges@\n", libname);
-               dlclose(h);
-               free(subid_nss);
-               subid_nss = NULL;
-               goto done;
+               goto close_lib;
        }
        subid_nss->find_subid_owners = dlsym(h, "shadow_subid_find_subid_owners");
        if (!subid_nss->find_subid_owners) {
                fprintf(shadow_logfd, "%s did not provide @find_subid_owners@\n", libname);
-               dlclose(h);
-               free(subid_nss);
-               subid_nss = NULL;
-               goto done;
+               goto close_lib;
        }
        subid_nss->handle = h;
+       goto done;
+
+close_lib:
+       dlclose(h);
+       free(subid_nss);
+null_subid:
+       subid_nss = NULL;
 
 done:
        atomic_store(&nss_init_completed, true);