From bd0231c96bf651918894c8afe4593e2efecf5da6 Mon Sep 17 00:00:00 2001 From: David Zeuthen Date: Wed, 9 Sep 2015 18:15:11 -0400 Subject: [PATCH] fs_mgr: Error out if unable to determine slot_suffix Instead of falling back to suffix _a, we now error out if neither the kernel commandline nor the misc partition specifies the suffix. It's cleaner this way. Change-Id: I3f58928a664433504ebdf8d0ee05a319be5097cf --- fs_mgr/fs_mgr_slotselect.c | 35 ++++++++++++++--------------------- 1 file changed, 14 insertions(+), 21 deletions(-) diff --git a/fs_mgr/fs_mgr_slotselect.c b/fs_mgr/fs_mgr_slotselect.c index 99dcd0e53..ca07b189b 100644 --- a/fs_mgr/fs_mgr_slotselect.c +++ b/fs_mgr/fs_mgr_slotselect.c @@ -78,10 +78,11 @@ static int get_active_slot_suffix_from_misc(struct fstab *fstab, return 0; } -// Gets slot_suffix from either the kernel cmdline / firmware, the -// misc partition or built-in fallback. -static void get_active_slot_suffix(struct fstab *fstab, char *out_suffix, - size_t suffix_len) +// Gets slot_suffix from either the kernel cmdline / firmware or the +// misc partition. Sets |out_suffix| on success and returns 0. Returns +// -1 if slot_suffix could not be determined. +static int get_active_slot_suffix(struct fstab *fstab, char *out_suffix, + size_t suffix_len) { char propbuf[PROPERTY_VALUE_MAX]; @@ -91,30 +92,19 @@ static void get_active_slot_suffix(struct fstab *fstab, char *out_suffix, property_get("ro.boot.slot_suffix", propbuf, ""); if (propbuf[0] != '\0') { strncpy(out_suffix, propbuf, suffix_len); - return; + return 0; } // If we couldn't get the suffix from the kernel cmdline, try the // the misc partition. if (get_active_slot_suffix_from_misc(fstab, out_suffix, suffix_len) == 0) { INFO("Using slot suffix \"%s\" from misc\n", out_suffix); - return; + return 0; } - // If that didn't work, fall back to _a. The reasoning here is - // that since the fstab has the slotselect option set (otherwise - // we wouldn't end up here) we must assume that partitions are - // indeed set up for A/B. This corner-case is important because we - // may be on this codepath on newly provisioned A/B devices where - // misc isn't set up properly (it's just zeroes) and the - // bootloader does not (yet) natively support A/B. - // - // Why '_a'? Because that's what system/extras/boot_control_copy - // is using and since the bootloader isn't A/B aware we assume - // slots are set up this way. - WARNING("Could not determine slot suffix, falling back to \"_a\"\n"); - strncpy(out_suffix, "_a", suffix_len); - return; + ERROR("Error determining slot_suffix\n"); + + return -1; } // Updates |fstab| for slot_suffix. Returns 0 on success, -1 on error. @@ -130,7 +120,10 @@ int fs_mgr_update_for_slotselect(struct fstab *fstab) if (!got_suffix) { memset(suffix, '\0', sizeof(suffix)); - get_active_slot_suffix(fstab, suffix, sizeof(suffix) - 1); + if (get_active_slot_suffix(fstab, suffix, + sizeof(suffix) - 1) != 0) { + return -1; + } got_suffix = 1; }