diff options
| -rw-r--r-- | updater/blockimg.c | 38 |
1 files changed, 28 insertions, 10 deletions
diff --git a/updater/blockimg.c b/updater/blockimg.c index 90b55b2..d5344f9 100644 --- a/updater/blockimg.c +++ b/updater/blockimg.c @@ -635,12 +635,13 @@ lsout: } static int WriteStash(const char* base, const char* id, int blocks, uint8_t* buffer, - int checkspace) { + int checkspace, int *exists) { char *fn = NULL; char *cn = NULL; int fd = -1; int rc = -1; int res; + struct stat st; if (base == NULL || buffer == NULL) { goto wsout; @@ -658,6 +659,22 @@ static int WriteStash(const char* base, const char* id, int blocks, uint8_t* buf goto wsout; } + if (exists) { + res = stat(cn, &st); + + if (res == 0) { + // The file already exists and since the name is the hash of the contents, + // it's safe to assume the contents are identical (accidental hash collisions + // are unlikely) + fprintf(stderr, " skipping %d existing blocks in %s\n", blocks, cn); + *exists = 1; + rc = 0; + goto wsout; + } + + *exists = 0; + } + fprintf(stderr, " writing %d blocks to %s\n", blocks, cn); fd = TEMP_FAILURE_RETRY(open(fn, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, STASH_FILE_MODE)); @@ -821,7 +838,7 @@ static int SaveStash(const char* base, char** wordsave, uint8_t** buffer, size_t } fprintf(stderr, "stashing %d blocks to %s\n", blocks, id); - return WriteStash(base, id, blocks, *buffer, 0); + return WriteStash(base, id, blocks, *buffer, 0, NULL); } static int FreeStash(const char* base, const char* id) { @@ -997,6 +1014,7 @@ static int LoadSrcTgtVersion3(CommandParameters* params, RangeSet** tgt, int* sr int onehash, int* overlap) { char* srchash = NULL; char* tgthash = NULL; + int stash_exists = 0; int overlap_blocks = 0; int rc = -1; uint8_t* tgtbuffer = NULL; @@ -1052,13 +1070,16 @@ static int LoadSrcTgtVersion3(CommandParameters* params, RangeSet** tgt, int* sr fprintf(stderr, "stashing %d overlapping blocks to %s\n", *src_blocks, srchash); - if (WriteStash(params->stashbase, srchash, *src_blocks, params->buffer, 1) != 0) { + if (WriteStash(params->stashbase, srchash, *src_blocks, params->buffer, 1, + &stash_exists) != 0) { fprintf(stderr, "failed to stash overlapping source blocks\n"); goto v3out; } // Can be deleted when the write has completed - params->freestash = srchash; + if (!stash_exists) { + params->freestash = srchash; + } } // Source blocks have expected content, command can proceed @@ -1068,12 +1089,9 @@ static int LoadSrcTgtVersion3(CommandParameters* params, RangeSet** tgt, int* sr if (*overlap && LoadStash(params->stashbase, srchash, 1, NULL, ¶ms->buffer, ¶ms->bufsize, 1) == 0) { - // Overlapping source blocks were previously stashed, command can proceed - if (params->canwrite) { - // We didn't create the stash, so delete after write only if we will - // actually perform the write - params->freestash = srchash; - } + // Overlapping source blocks were previously stashed, command can proceed. + // We are recovering from an interrupted command, so we don't know if the + // stash can safely be deleted after this command. rc = 0; goto v3out; } |