X-Git-Url: http://git.cascardo.eti.br/?a=blobdiff_plain;f=ovsdb%2Flog.c;h=1e4c75ef2a77076e1620af440f62864672cba7ac;hb=HEAD;hp=9c2767cb7206a05ed1efa245e925033f3efce99e;hpb=02dd3123a0e312f1d33403e744af52dd6096f12d;p=cascardo%2Fovs.git diff --git a/ovsdb/log.c b/ovsdb/log.c index 9c2767cb7..1e4c75ef2 100644 --- a/ovsdb/log.c +++ b/ovsdb/log.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2009, 2010 Nicira Networks +/* Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -17,11 +17,11 @@ #include "log.h" -#include #include #include #include #include +#include #include #include "json.h" @@ -33,21 +33,19 @@ #include "transaction.h" #include "util.h" -#define THIS_MODULE VLM_ovsdb_log -#include "vlog.h" - enum ovsdb_log_mode { OVSDB_LOG_READ, OVSDB_LOG_WRITE }; struct ovsdb_log { + off_t prev_offset; off_t offset; char *name; struct lockfile *lockfile; FILE *stream; struct ovsdb_error *read_error; - struct ovsdb_error *write_error; + bool write_error; enum ovsdb_log_mode mode; }; @@ -73,12 +71,12 @@ ovsdb_log_open(const char *name, enum ovsdb_log_open_mode open_mode, *filep = NULL; - assert(locking == -1 || locking == false || locking == true); + ovs_assert(locking == -1 || locking == false || locking == true); if (locking < 0) { locking = open_mode != OVSDB_LOG_READ_ONLY; } if (locking) { - int retval = lockfile_lock(name, 0, &lockfile); + int retval = lockfile_lock(name, &lockfile); if (retval) { error = ovsdb_io_error(retval, "%s: failed to lock lockfile", name); @@ -93,10 +91,26 @@ ovsdb_log_open(const char *name, enum ovsdb_log_open_mode open_mode, } else if (open_mode == OVSDB_LOG_READ_WRITE) { flags = O_RDWR; } else if (open_mode == OVSDB_LOG_CREATE) { +#ifndef _WIN32 + if (stat(name, &s) == -1 && errno == ENOENT + && lstat(name, &s) == 0 && S_ISLNK(s.st_mode)) { + /* 'name' is a dangling symlink. We want to create the file that + * the symlink points to, but POSIX says that open() with O_EXCL + * must fail with EEXIST if the named file is a symlink. So, we + * have to leave off O_EXCL and accept the race. */ + flags = O_RDWR | O_CREAT; + } else { + flags = O_RDWR | O_CREAT | O_EXCL; + } +#else flags = O_RDWR | O_CREAT | O_EXCL; +#endif } else { - NOT_REACHED(); + OVS_NOT_REACHED(); } +#ifdef _WIN32 + flags = flags | O_BINARY; +#endif fd = open(name, flags, 0666); if (fd < 0) { const char *op = open_mode == OVSDB_LOG_CREATE ? "create" : "open"; @@ -120,9 +134,10 @@ ovsdb_log_open(const char *name, enum ovsdb_log_open_mode open_mode, file->name = xstrdup(name); file->lockfile = lockfile; file->stream = stream; + file->prev_offset = 0; file->offset = 0; file->read_error = NULL; - file->write_error = NULL; + file->write_error = false; file->mode = OVSDB_LOG_READ; *filep = file; return NULL; @@ -143,7 +158,6 @@ ovsdb_log_close(struct ovsdb_log *file) fclose(file->stream); lockfile_unlock(file->lockfile); ovsdb_error_destroy(file->read_error); - ovsdb_error_destroy(file->write_error); free(file); } } @@ -283,9 +297,10 @@ ovsdb_log_read(struct ovsdb_log *file, struct json **jsonp) goto error; } + file->prev_offset = file->offset; file->offset = data_offset + data_length; *jsonp = json; - return 0; + return NULL; error: file->read_error = ovsdb_error_clone(error); @@ -293,6 +308,22 @@ error: return error; } +/* Causes the log record read by the previous call to ovsdb_log_read() to be + * effectively discarded. The next call to ovsdb_log_write() will overwrite + * that previously read record. + * + * Calling this function more than once has no additional effect. + * + * This function is useful when ovsdb_log_read() successfully reads a record + * but that record does not make sense at a higher level (e.g. it specifies an + * invalid transaction). */ +void +ovsdb_log_unread(struct ovsdb_log *file) +{ + ovs_assert(file->mode == OVSDB_LOG_READ); + file->offset = file->prev_offset; +} + struct ovsdb_error * ovsdb_log_write(struct ovsdb_log *file, struct json *json) { @@ -304,10 +335,9 @@ ovsdb_log_write(struct ovsdb_log *file, struct json *json) json_string = NULL; - if (file->write_error) { - return ovsdb_error_clone(file->write_error); - } else if (file->mode == OVSDB_LOG_READ) { + if (file->mode == OVSDB_LOG_READ || file->write_error) { file->mode = OVSDB_LOG_WRITE; + file->write_error = false; if (fseeko(file->stream, file->offset, SEEK_SET)) { error = ovsdb_io_error(errno, "%s: cannot seek to offset %lld", file->name, (long long int) file->offset); @@ -333,7 +363,7 @@ ovsdb_log_write(struct ovsdb_log *file, struct json *json) /* Compose header. */ sha1_bytes(json_string, length, sha1); - snprintf(header, sizeof header, "%s%zu "SHA1_FMT"\n", + snprintf(header, sizeof header, "%s%"PRIuSIZE" "SHA1_FMT"\n", magic, length, SHA1_ARGS(sha1)); /* Write. */ @@ -352,10 +382,10 @@ ovsdb_log_write(struct ovsdb_log *file, struct json *json) file->offset += strlen(header) + length; free(json_string); - return 0; + return NULL; error: - file->write_error = ovsdb_error_clone(error); + file->write_error = true; free(json_string); return error; } @@ -366,6 +396,14 @@ ovsdb_log_commit(struct ovsdb_log *file) if (fsync(fileno(file->stream))) { return ovsdb_io_error(errno, "%s: fsync failed", file->name); } - return 0; + return NULL; } +/* Returns the current offset into the file backing 'log', in bytes. This + * reflects the number of bytes that have been read or written in the file. If + * the whole file has been read, this is the file size. */ +off_t +ovsdb_log_get_offset(const struct ovsdb_log *log) +{ + return log->offset; +}