Improve editing GPT partition type GUID's by rejecting partition

id's that have no associated GUID, rather than disabling the
partition.

If the current partition type is a GUID with no corresponding
partition id, display and use that GUID as the default value.

Less surprising behaviour all round.

diff --git a/sbin/fdisk/cmd.c b/sbin/fdisk/cmd.c
index 181e93e..5153b67 100644 (file)
--- a/sbin/fdisk/cmd.c
+++ b/sbin/fdisk/cmd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cmd.c,v 1.142 2021/08/29 17:29:14 krw Exp $   */
+/*     $OpenBSD: cmd.c,v 1.143 2021/09/01 20:08:32 krw Exp $   */
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -42,7 +42,8 @@ int            setpid(const int, struct mbr *);
 int             parsepn(const char *);
 
 int             ask_num(const char *, int, int, int);
-int             ask_pid(const int, struct uuid *);
+int             ask_pid(const int);
+struct uuid    *ask_uuid(const struct uuid *);
 char           *ask_string(const char *, const char *);
 
 extern const unsigned char     manpage[];
@@ -301,7 +302,7 @@ gsetpid(const int pn)
 {
        struct uuid              gp_type, gp_guid;
        struct gpt_partition    *gg;
-       int                      num, status;
+       int                      status;
 
        gg = &gp[pn];
 
@@ -315,10 +316,7 @@ gsetpid(const int pn)
                return -1;
        }
 
-       /* Ask for partition type or GUID. */
-       num = ask_pid(PRT_uuid_to_type(&gp_type), &gp_type);
-       if (num <= 0xff)
-               gp_type = *(PRT_type_to_uuid(num));
+       gp_type = *ask_uuid(&gp_type);
        if (PRT_protected_guid(&gp_type)) {
                printf("can't change partition type to %s\n",
                    PRT_uuid_to_typename(&gp_type));
@@ -350,7 +348,7 @@ setpid(const int pn, struct mbr *mbr)
        PRT_print(0, NULL, NULL);
        PRT_print(pn, pp, NULL);
 
-       pp->prt_id = ask_pid(pp->prt_id, NULL);
+       pp->prt_id = ask_pid(pp->prt_id);
 
        return 0;
 }
@@ -602,10 +600,10 @@ ask_num(const char *str, int dflt, int low, int high)
 }
 
 int
-ask_pid(const int dflt, struct uuid *guid)
+ask_pid(const int dflt)
 {
        char                    lbuf[100];
-       int                     num, status;
+       int                     num;
 
        for (;;) {
                printf("Partition id ('0' to disable) [01 - FF]: [%02X] ", dflt);
@@ -619,12 +617,6 @@ ask_pid(const int dflt, struct uuid *guid)
                        continue;
                }
 
-               if (guid && strlen(lbuf) == UUID_STR_LEN) {
-                       uuid_from_string(lbuf, guid, &status);
-                       if (status == uuid_s_ok)
-                               return 0x100;
-               }
-
                num = hex_octet(lbuf);
                if (num != -1)
                        return num;
@@ -633,6 +625,73 @@ ask_pid(const int dflt, struct uuid *guid)
        }
 }
 
+struct uuid *
+ask_uuid(const struct uuid *olduuid)
+{
+       static struct uuid       uuid;
+       char                     lbuf[100];
+       char                    *dflt = NULL;
+       int                      status;
+       int                      num = 0;
+
+       uuid = *olduuid;
+       if (uuid_is_nil(&uuid, NULL) == 0) {
+               num = PRT_uuid_to_type(&uuid);
+               if (num == 0) {
+                       uuid_to_string(&uuid, &dflt, &status);
+                       if (status != uuid_s_ok) {
+                               printf("uuid_to_string() failed\n");
+                               goto done;
+                       }
+               }
+       }
+       if (dflt == NULL) {
+               if (asprintf(&dflt, "%X", num) == -1) {
+                       warn("asprintf()");
+                       goto done;
+               }
+       }
+
+       for (;;) {
+               printf("Partition id ('0' to disable) [01 - FF, <uuid>]: [%s] ",
+                   dflt);
+               printf("(? for help) ");
+               string_from_line(lbuf, sizeof(lbuf), TRIMMED);
+
+               if (strcmp(lbuf, "?") == 0) {
+                       PRT_printall();
+                       continue;
+               } else if (strlen(lbuf) == 0) {
+                       uuid = *olduuid;
+                       goto done;
+               }
+
+               uuid_from_string(lbuf, &uuid, &status);
+               if (status == uuid_s_ok)
+                       goto done;
+
+               num = hex_octet(lbuf);
+               switch (num) {
+               case -1:
+                       printf("'%s' is not a valid partition id\n", lbuf);
+                       break;
+               case 0:
+                       uuid_create_nil(&uuid, NULL);
+                       goto done;
+               default:
+                       uuid = *PRT_type_to_uuid(num);
+                       if (uuid_is_nil(&uuid, NULL) == 0)
+                               goto done;
+                       printf("'%s' has no associated UUID\n", lbuf);
+                       break;
+               }
+       }
+
+ done:
+       free(dflt);
+       return &uuid;
+}
+
 char *
 ask_string(const char *prompt, const char *oval)
 {