disk/part.c: ensure strings in struct disk_partition are valid after successful get_info

Not all ->get_info implementations necessarily populate all the string
members of struct disk_partition.

Currently, only part_get_info_by_type() (and thereby part_get_info)
ensure that the uuid strings are initialized; part_get_info_by_type()
and part_get_info_by_uuid() do not. In fact, the latter could lead to
a false positive match - if the ->get_info backend does not populate
info->uuid, stale contents in info could cause the strncasecmp() to
succeed.

None of the functions currently ensure that the ->name and ->type
strings are initialized.

Instead of forcing all callers of any of these functions to
pre-initialize info, or all implementations of the ->get_info method
to ensure there are valid C strings in all four fields, create a small
helper function and factor all invocations of ->get_info through that.

This also consolidates the -ENOSYS check and standardizes on using
log_debug() for reporting absence, instead of the current mix of
PRINTF and log_debug(). It does mean we have to special-case -ENOSYS
in the error cases inside the loops in the _by_uuid() and _by_name()
functions, but it's still a net win in #LOC.

Acked-by: Quentin Schulz <[email protected]>
Signed-off-by: Rasmus Villemoes <[email protected]>
Tested-by: Anshul Dalal <[email protected]>

1 files changed, 2 insertions, 2 deletions

diff --git a/cmd/gpt.c b/cmd/gpt.c
index e18e5036a06..84221881c39 100644
--- a/cmd/gpt.c
+++ b/cmd/gpt.c
@@ -724,7 +724,7 @@ static int gpt_enumerate(struct blk_desc *desc)
 			continue;
 
 		for (i = 1; i < part_drv->max_entries; i++) {
-			ret = part_drv->get_info(desc, i, &pinfo);
+			ret = part_driver_get_info(part_drv, desc, i, &pinfo);
 			if (ret)
 				continue;
 
@@ -820,7 +820,7 @@ static int gpt_setenv(struct blk_desc *desc, const char *name)
 		int i;
 
 		for (i = 1; i < part_drv->max_entries; i++) {
-			ret = part_drv->get_info(desc, i, &pinfo);
+			ret = part_driver_get_info(part_drv, desc, i, &pinfo);
 			if (ret)
 				continue;