Re: [Libguestfs] [libguestfs-common PATCH 05/12] options: replace NULL-termination with number-of-elements in get_keys()

Currently, get_keys() returns a NULL-terminated array of (char*) elements. In a later patch in this series, we'll want to change the element type to a structure type, at which point the NULL-termination would become awkward. Replace the NULL-termination scheme with the number-of-elements scheme. No behavioral changes. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1809453 Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- options/options.h | 4 +++- options/decrypt.c | 17 +++++++------- options/keys.c | 24 ++++++++++++++------ 3 files changed, 29 insertions(+), 16 deletions(-) diff --git a/options/options.h b/options/options.h index 80df91a85f98..d7a3aeff6f41 100644 --- a/options/options.h +++ b/options/options.h @@ -149,11 +149,13 @@ extern void inspect_mount_root (guestfs_h *g, const char *root); #define inspect_mount() inspect_mount_handle (g, ks) extern void print_inspect_prompt (void); /* in key.c */ extern char *read_key (const char *param); -extern char **get_keys (struct key_store *ks, const char *device, const char *uuid); +extern char **get_keys (struct key_store *ks, const char *device, const char *uuid, + size_t *nr_matches); +extern void free_keys (char **keys, size_t nr_matches); extern struct key_store *key_store_add_from_selector (struct key_store *ks, const char *selector); extern struct key_store *key_store_import_key (struct key_store *ks, const struct key_store_key *key); extern void free_key_store (struct key_store *ks); /* in options.c */ diff --git a/options/decrypt.c b/options/decrypt.c index 1cd7b627e264..c25b5888d8b4 100644 --- a/options/decrypt.c +++ b/options/decrypt.c @@ -122,14 +122,14 @@ decrypt_mountables (guestfs_h *g, const char * const *mountables, const char *mountable; while ((mountable = *mnt_scan++) != NULL) { CLEANUP_FREE char *type = NULL; CLEANUP_FREE char *uuid = NULL; - CLEANUP_FREE_STRING_LIST char **keys = NULL; + char **keys; + size_t nr_matches; CLEANUP_FREE char *mapname = NULL; - const char * const *key_scan; - const char *key; + size_t scan; type = guestfs_vfs_type (g, mountable); if (type == NULL) continue; @@ -142,37 +142,38 @@ decrypt_mountables (guestfs_h *g, const char * const *mountables, continue; /* Grab the keys that we should try with this device, based on device name, * or UUID (if any). */ - keys = get_keys (ks, mountable, uuid); - assert (keys[0] != NULL); + keys = get_keys (ks, mountable, uuid, &nr_matches); + assert (nr_matches > 0); /* Generate a node name for the plaintext (decrypted) device node. */ if (uuid == NULL || asprintf (&mapname, "luks-%s", uuid) == -1) mapname = make_mapname (mountable); /* Try each key in turn. */ - key_scan = (const char * const *)keys; - while ((key = *key_scan++) != NULL) { + for (scan = 0; scan < nr_matches; ++scan) { + const char *key = keys[scan]; int r; guestfs_push_error_handler (g, NULL, NULL); r = guestfs_cryptsetup_open (g, mountable, key, mapname, -1); guestfs_pop_error_handler (g); if (r == 0) break; } - if (key == NULL) + if (scan == nr_matches) error (EXIT_FAILURE, 0, _("could not find key to open LUKS encrypted %s.\n\n" "Try using --key on the command line.\n\n" "Original error: %s (%d)"), mountable, guestfs_last_error (g), guestfs_last_errno (g)); + free_keys (keys, nr_matches); decrypted_some = true; } return decrypted_some; } diff --git a/options/keys.c b/options/keys.c index 8713372a305e..1d97d980a460 100644 --- a/options/keys.c +++ b/options/keys.c @@ -124,11 +124,12 @@ read_first_line_from_file (const char *filename) /* Return the key(s) matching this particular device from the * keystore. There may be multiple. If none are read from the * keystore, ask the user. */ char ** -get_keys (struct key_store *ks, const char *device, const char *uuid) +get_keys (struct key_store *ks, const char *device, const char *uuid, + size_t *nr_matches) { size_t i, j, nmemb; char **r; char *s; @@ -137,18 +138,16 @@ get_keys (struct key_store *ks, const char *device, const char *uuid) */ nmemb = 1; if (ks && ks->nr_keys > nmemb) nmemb = ks->nr_keys; - /* make room for the terminating NULL */ - if (nmemb == (size_t)-1) + if (nmemb > (size_t)-1 / sizeof *r) error (EXIT_FAILURE, 0, _("size_t overflow")); - nmemb++; - r = calloc (nmemb, sizeof (char *)); + r = malloc (nmemb * sizeof *r); if (r == NULL) - error (EXIT_FAILURE, errno, "calloc"); + error (EXIT_FAILURE, errno, "malloc"); j = 0; if (ks) { for (i = 0; i < ks->nr_keys; ++i) { @@ -175,16 +174,27 @@ get_keys (struct key_store *ks, const char *device, const char *uuid) if (j == 0) { /* Key not found in the key store, ask the user for it. */ s = read_key (device); if (!s) error (EXIT_FAILURE, 0, _("could not read key from user")); - r[0] = s; + r[j++] = s; } + *nr_matches = j; return r; } +void +free_keys (char **keys, size_t nr_matches) +{ + size_t i; + + for (i = 0; i < nr_matches; ++i) + free (keys[i]); + free (keys); +} + struct key_store * key_store_add_from_selector (struct key_store *ks, const char *selector) { CLEANUP_FREE_STRING_LIST char **fields = guestfs_int_split_string (':', selector);