This ain't no loop

This was to a loop, as "1234" is to computer security.

No really; a loop that ends in a (forward) goto, and has no continue in it.

Still want a loop?  Take two:

 #define loopity_loop() do { for (;;) { break; } continue; } while (0-0)

Closes: <https://github.com/shadow-maint/shadow/issues/736>
Easter-egg: 8492dee6632e ("subids: support nsswitch")
Signed-off-by: Alejandro Colomar <alx@kernel.org>

diff --git a/lib/nss.c b/lib/nss.c
index 3864a87cff9291a73a6223e11a59ac72ce563130..30199a63e0a4a473f09c04326215e4d9084d996d 100644 (file)
--- a/lib/nss.c
+++ b/lib/nss.c
@@ -68,6 +68,9 @@ void nss_init(const char *nsswitch_path) {
                return;
        }
        while ((getline(&line, &len, nssfp)) != -1) {
+               char libname[65];
+               void *h;
+
                if (line[0] == '\0' || line[0] == '#')
                        continue;
                if (strlen(line) < 8)
@@ -79,65 +82,62 @@ void nss_init(const char *nsswitch_path) {
                        p++;
                if (!*p)
                        continue;
-               for (token = strtok_r(p, " \n\t", &saveptr);
-                    token;
-                    token = strtok_r(NULL, " \n\t", &saveptr)) {
-                       char libname[65];
-                       void *h;
-                       if (strcmp(token, "files") == 0) {
-                               subid_nss = NULL;
-                               goto done;
-                       }
-                       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;
-                       }
-                       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;
-                       }
-                       subid_nss = MALLOC(struct subid_nss_ops);
-                       if (!subid_nss) {
-                               dlclose(h);
-                               goto done;
-                       }
-                       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;
-                       }
-                       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;
-                       }
-                       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;
-                       }
-                       subid_nss->handle = h;
+               token = strtok_r(p, " \n\t", &saveptr);
+               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;
                }
-               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;
+               if (strcmp(token, "files") == 0) {
+                       subid_nss = NULL;
+                       goto done;
+               }
+               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;
+               }
+               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;
+               }
+               subid_nss = MALLOC(struct subid_nss_ops);
+               if (!subid_nss) {
+                       dlclose(h);
+                       goto done;
+               }
+               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;
+               }
+               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;
+               }
+               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;
+               }
+               subid_nss->handle = h;
                goto done;
        }