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lib_log: better data safety, rework error handling

This commit is contained in:
Thomas Schoebel-Theuer 2013-01-04 13:34:15 +01:00
parent bcf323c254
commit 44f45025f8
1 changed files with 41 additions and 35 deletions
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76
lib_log.c
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@ -381,7 +381,7 @@ int log_scan(void *buf, int len, loff_t file_pos, int file_offset, struct log_he
*payload = NULL; *payload = NULL;
*payload_len = 0; *payload_len = 0;
for (i = 0; i < len; i += sizeof(long)) { for (i = 0; i < len && i <= len - OVERHEAD; i += sizeof(long)) {
long long start_magic; long long start_magic;
char format_version; char format_version;
char valid_flag; char valid_flag;
@ -394,32 +394,32 @@ int log_scan(void *buf, int len, loff_t file_pos, int file_offset, struct log_he
offset = i; offset = i;
DATA_GET(buf, offset, start_magic); DATA_GET(buf, offset, start_magic);
if (start_magic != START_MAGIC) { if (unlikely(start_magic != START_MAGIC)) {
if (start_magic != 0) if (start_magic != 0)
dirty = true; dirty = true;
continue; continue;
} }
restlen = len - i; restlen = len - i;
if (restlen < START_OVERHEAD) { if (unlikely(restlen < START_OVERHEAD)) {
MARS_ERR(SCAN_TXT "magic found, but restlen is too small\n", SCAN_PAR); MARS_WRN(SCAN_TXT "magic found, but restlen is too small\n", SCAN_PAR);
return -EBADMSG; return -EAGAIN;
} }
DATA_GET(buf, offset, format_version); DATA_GET(buf, offset, format_version);
if (format_version != FORMAT_VERSION) { if (unlikely(format_version != FORMAT_VERSION)) {
MARS_ERR(SCAN_TXT "found unknown data format %d\n", SCAN_PAR, (int)format_version); MARS_ERR(SCAN_TXT "found unknown data format %d\n", SCAN_PAR, (int)format_version);
return -EBADMSG; return -EBADMSG;
} }
DATA_GET(buf, offset, valid_flag); DATA_GET(buf, offset, valid_flag);
if (!valid_flag) { if (unlikely(!valid_flag)) {
MARS_WRN(SCAN_TXT "data is marked invalid (was there a short write?)\n", SCAN_PAR); MARS_WRN(SCAN_TXT "data is explicitly marked invalid (was there a short write?)\n", SCAN_PAR);
continue; continue;
} }
DATA_GET(buf, offset, total_len); DATA_GET(buf, offset, total_len);
if (total_len > restlen) { if (unlikely(total_len > restlen)) {
MARS_ERR(SCAN_TXT "data is longer than expected, total_len = %d restlen = %d\n", SCAN_PAR, total_len, restlen); MARS_WRN(SCAN_TXT "total_len = %d but available data restlen = %d. Was the logfile truncated?\n", SCAN_PAR, total_len, restlen);
return -EBADMSG; return -EAGAIN;
} }
memset(lh, 0, sizeof(struct log_header)); memset(lh, 0, sizeof(struct log_header));
@ -436,21 +436,22 @@ int log_scan(void *buf, int len, loff_t file_pos, int file_offset, struct log_he
offset += lh->l_len; offset += lh->l_len;
restlen = len - offset; restlen = len - offset;
if (restlen < END_OVERHEAD) { if (unlikely(restlen < END_OVERHEAD)) {
MARS_WRN(SCAN_TXT "magic found, but restlen %d is too small\n", SCAN_PAR, restlen); MARS_WRN(SCAN_TXT "restlen %d is too small\n", SCAN_PAR, restlen);
continue; return -EAGAIN;
} }
DATA_GET(buf, offset, end_magic); DATA_GET(buf, offset, end_magic);
if (end_magic != END_MAGIC) { if (unlikely(end_magic != END_MAGIC)) {
MARS_WRN(SCAN_TXT "bad end_magic 0x%llx\n", SCAN_PAR, end_magic); MARS_WRN(SCAN_TXT "bad end_magic 0x%llx, is the logfile truncated?\n", SCAN_PAR, end_magic);
continue; return -EBADMSG;
} }
DATA_GET(buf, offset, lh->l_crc); DATA_GET(buf, offset, lh->l_crc);
DATA_GET(buf, offset, valid_copy); DATA_GET(buf, offset, valid_copy);
if (valid_copy != 1) {
MARS_WRN(SCAN_TXT "found uncompleted / invalid data, len = %d, valid_flag = %d\n", SCAN_PAR, lh->l_len, (int)valid_copy); if (unlikely(valid_copy != 1)) {
continue; MARS_WRN(SCAN_TXT "found data marked as uncompleted / invalid, len = %d, valid_flag = %d\n", SCAN_PAR, lh->l_len, (int)valid_copy);
return -EBADMSG;
} }
// skip spares // skip spares
@ -461,7 +462,7 @@ int log_scan(void *buf, int len, loff_t file_pos, int file_offset, struct log_he
DATA_GET(buf, offset, lh->l_written.tv_nsec); DATA_GET(buf, offset, lh->l_written.tv_nsec);
if (unlikely(lh->l_seq_nr != *seq_nr + 1 && lh->l_seq_nr && *seq_nr)) { if (unlikely(lh->l_seq_nr != *seq_nr + 1 && lh->l_seq_nr && *seq_nr)) {
MARS_ERR("log sequence number %u mismatch, expected was %u\n", lh->l_seq_nr, *seq_nr + 1); MARS_ERR(SCAN_TXT "log sequence number %u mismatch, expected was %u\n", SCAN_PAR, lh->l_seq_nr, *seq_nr + 1);
return -EBADMSG; return -EBADMSG;
} }
*seq_nr = lh->l_seq_nr; *seq_nr = lh->l_seq_nr;
@ -470,30 +471,31 @@ int log_scan(void *buf, int len, loff_t file_pos, int file_offset, struct log_he
unsigned char checksum[mars_digest_size]; unsigned char checksum[mars_digest_size];
mars_digest(checksum, buf + found_offset, lh->l_len); mars_digest(checksum, buf + found_offset, lh->l_len);
if (unlikely(*(int*)checksum != lh->l_crc)) { if (unlikely(*(int*)checksum != lh->l_crc)) {
MARS_ERR("data checksumming mismatch, length = %d\n", lh->l_len); MARS_ERR(SCAN_TXT "data checksumming mismatch, length = %d\n", SCAN_PAR, lh->l_len);
return -EBADMSG; return -EBADMSG;
} }
} }
// last check // last check
if (total_len != offset - i) { if (unlikely(total_len != offset - i)) {
MARS_WRN(SCAN_TXT "size mismatch: %d != %d\n", SCAN_PAR, total_len, offset - i); MARS_ERR(SCAN_TXT "internal size mismatch: %d != %d\n", SCAN_PAR, total_len, offset - i);
// just warn, but no consequences: better use the data, it has been checked by lots of magics return -EBADMSG;
} }
// Success... // Success...
*payload = buf + found_offset; *payload = buf + found_offset;
*payload_len = lh->l_len; *payload_len = lh->l_len;
goto done;
}
offset = i;
done: // don't cry when nullbytes have been skipped
// don't cry when nullbytes have been skipped if (i > 0 && dirty) {
if (i > 0 && dirty) { MARS_WRN(SCAN_TXT "skipped %d dirty bytes to find valid data\n", SCAN_PAR, i);
MARS_WRN("skipped %d dirty bytes at offset %d to find valid data\n", i, offset); }
return offset;
} }
return offset;
MARS_ERR("could not find any useful data within len=%d bytes\n", len);
return -EAGAIN;
} }
static static
@ -551,6 +553,10 @@ restart:
} }
goto done_free; goto done_free;
} }
if (unlikely(mref->ref_len <= OVERHEAD)) { // EOF
status = 0;
goto done_put;
}
SETUP_CALLBACK(mref, log_read_endio, logst); SETUP_CALLBACK(mref, log_read_endio, logst);
mref->ref_rw = READ; mref->ref_rw = READ;
@ -587,9 +593,9 @@ restart:
goto done_put; goto done_put;
} }
// memorize success // memoize success
logst->offset += status; logst->offset += status;
if (logst->offset > mref->ref_len - logst->chunk_size) { if (logst->offset + (logst->max_size + OVERHEAD) * 2 >= mref->ref_len) {
logst->do_free = true; logst->do_free = true;
} }