ksmbd-tools: handle unset ret

[neheb]

If g_mapped_file_get_length returns 0 or SIZE_MAX, the loop does not get executed and ret does not get set

Move the assignment out of the loop and change to while loop.

Found with GCC's -fanalyzer.

[neheb]

I assume CI fails now because ubuntu-latest was recently updated.

[namjaejeon]

g_mapped_file_unref() is not called on error handling ?. So, should we use goto out_unref instead of out_close ?

[neheb]

ah yes you're right. copy/paste mistake looks like.

[atheik]

@neheb,

The purpose of the (size_t)-1 check here is not to check if g_mapped_file_get_length() returned it.
Instead, its purpose is to handle situations where there is no trailing newline at the end of the file.
With your changes, the handling of such files breaks:

==8003== Invalid read of size 1
==8003==    at 0x484F239: memchr (vg_replace_strmem.c:986)
==8003==    by 0x111407: __mmap_parse_file (config_parser.c:251)
==8003==    by 0x1122BD: cp_parse_smbconf (config_parser.c:691)
==8003==    by 0x113FE4: load_config (tools.c:295)
==8003==    by 0x11CD64: worker_init (mountd.c:259)
==8003==    by 0x11CD64: manager_init (mountd.c:396)
==8003==    by 0x11D91F: mountd_main (mountd.c:456)
==8003==    by 0x4A26E07: (below main) (libc_start_call_main.h:58)
==8003==  Address 0x485c000 is not stack'd, malloc'd or (recently) free'd

Note that g_mapped_file_get_length() does not return 0 for us, since the preceding g_mapped_file_get_contents() returns NULL for empty files. If you would like to handle g_mapped_file_get_length() actually returning (size_t)-1 (and also satisfy the static analyzer), then please do this instead and remove the other changes:

diff --git a/tools/config_parser.c b/tools/config_parser.c
index b890b96..0040061 100644
--- a/tools/config_parser.c
+++ b/tools/config_parser.c
@@ -238,7 +238,7 @@ static int __mmap_parse_file(const char *path, process_entry_fn *process_entry)
 		goto out_unref;
 	}
 
-	for (len = g_mapped_file_get_length(file);
+	for (ret = -EINVAL, len = g_mapped_file_get_length(file);
 	     len > 0 && len != (size_t)-1;
 	     len -= delim - contents + 1, contents = delim + 1) {
 		g_autofree char *entry = NULL;