libfdisk: fix get_partition_unused_primary()

Was:
Mentioned function returns -1 if adding of primary partition is
impossible. Caller treats this value as size_t (res variable) and then
compares it for negative values, totally ignoring errors.

Becomes:
Now function takes address to variable and fills it with partition
number. Caller treats return value as int and use it appropriately.

[kzak@redhat.com: - don't mix return code and partno at all]

Signed-off-by: Boris Egorov <egorov@linux.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libfdisk/src/dos.c b/libfdisk/src/dos.c
index b4456a9477527452b8b5bd3df5a906df0aadfe31..1972ce252914c4176308cedb3d212618579fd35e 100644 (file)
--- a/libfdisk/src/dos.c
+++ b/libfdisk/src/dos.c
@@ -186,24 +186,28 @@ static int is_cleared_partition(struct dos_partition *p)
 }
 
 static int get_partition_unused_primary(struct fdisk_context *cxt,
-                                       struct fdisk_partition *pa)
+                                       struct fdisk_partition *pa,
+                                       size_t *partno)
 {
-       size_t org = cxt->label->nparts_max, n;
+       size_t org, n;
        int rc;
 
+       assert(cxt);
+       assert(cxt->label);
+       assert(partno);
+
+       org = cxt->label->nparts_max;
+
        cxt->label->nparts_max = 4;
        rc = fdisk_partition_next_partno(pa, cxt, &n);
        cxt->label->nparts_max = org;
 
-       switch (rc) {
-       case 1:
+       if (rc == 1) {
                fdisk_info(cxt, _("All primary partitions have been defined already."));
-               return -1;
-       case 0:
-               return n;
-       default:
-               return rc;
-       }
+               rc = -1;
+       } else if (rc == 0)
+               *partno = n;
+       return rc;
 }
 
 static int seek_sector(struct fdisk_context *cxt, sector_t secno)
@@ -1464,8 +1468,8 @@ static int dos_add_partition(struct fdisk_context *cxt,
                        fdisk_warnx(cxt, _("Extended partition already exists."));
                        return -EINVAL;
                }
-               res = get_partition_unused_primary(cxt, pa);
-               if (res >= 0) {
+               rc = get_partition_unused_primary(cxt, pa, &res);
+               if (rc == 0) {
                        rc = add_partition(cxt, res, pa);
                        goto done;
                }
@@ -1473,8 +1477,8 @@ static int dos_add_partition(struct fdisk_context *cxt,
        /* pa specifies start, but outside extended partition */
        } else if (pa && fdisk_partition_has_start(pa) && l->ext_offset) {
                DBG(LABEL, ul_debug("DOS: pa template %p: add primary", pa));
-               res = get_partition_unused_primary(cxt, pa);
-               if (res >= 0) {
+               rc = get_partition_unused_primary(cxt, pa, &res);
+               if (rc == 0) {
                        rc = add_partition(cxt, res, pa);
                        goto done;
                }
@@ -1531,8 +1535,8 @@ static int dos_add_partition(struct fdisk_context *cxt,
        } else if (cxt->label->nparts_max >= MAXIMUM_PARTS) {
                fdisk_info(cxt, _("All logical partitions are in use. "
                                  "Adding a primary partition."));
-               res = get_partition_unused_primary(cxt, pa);
-               if (res >= 0)
+               rc = get_partition_unused_primary(cxt, pa, &res);
+               if (rc == 0)
                        rc = add_partition(cxt, res, pa);
        } else {
                char hint[BUFSIZ];
@@ -1541,8 +1545,8 @@ static int dos_add_partition(struct fdisk_context *cxt,
 
                /* the default layout for scripts is to create primary partitions */
                if (cxt->script) {
-                       res = get_partition_unused_primary(cxt, pa);
-                       if (res >= 0)
+                       rc = get_partition_unused_primary(cxt, pa, &res);
+                       if (rc == 0)
                                rc = add_partition(cxt, res, pa);
                        goto done;
                }
@@ -1573,16 +1577,16 @@ static int dos_add_partition(struct fdisk_context *cxt,
                fdisk_free_ask(ask);
 
                if (c == 'p') {
-                       res = get_partition_unused_primary(cxt, pa);
-                       if (res >= 0)
+                       rc = get_partition_unused_primary(cxt, pa, &res);
+                       if (rc == 0)
                                rc = add_partition(cxt, res, pa);
                        goto done;
                } else if (c == 'l' && l->ext_offset) {
                        rc = add_logical(cxt, pa, &res);
                        goto done;
                } else if (c == 'e' && !l->ext_offset) {
-                       res = get_partition_unused_primary(cxt, pa);
-                       if (res >= 0) {
+                       rc = get_partition_unused_primary(cxt, pa, &res);
+                       if (rc == 0) {
                                struct fdisk_partition *xpa = NULL;
                                struct fdisk_parttype *t;
 
@@ -1607,7 +1611,7 @@ static int dos_add_partition(struct fdisk_context *cxt,
 done:
        if (rc == 0) {
                cxt->label->nparts_cur++;
-               if (partno && res >= 0)
+               if (partno)
                        *partno = res;
        }
        return rc;