[Xen-devel] [PATCH 1/6] xenconsoled: introduce log file abstraction

[Wei Liu <wei.liu2@xxxxxxxxxx>]

It will be used to handle hypervsior log and guest console log.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/console/daemon/logfile.c | 229 +++++++++++++++++++++++++++++++++++++++++
 tools/console/daemon/logfile.h |  57 ++++++++++
 2 files changed, 286 insertions(+)
 create mode 100644 tools/console/daemon/logfile.c
 create mode 100644 tools/console/daemon/logfile.h

diff --git a/tools/console/daemon/logfile.c b/tools/console/daemon/logfile.c
new file mode 100644
index 0000000..ad73f8e
--- /dev/null
+++ b/tools/console/daemon/logfile.c
@@ -0,0 +1,229 @@
+/*
+ *  Copyright (C) Citrix 2016
+ *  Author(s): Wei Liu <wei.liu2@xxxxxxxxxx>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+#define _GNU_SOURCE
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "utils.h"
+#include "logfile.h"
+
+static void logfile_entry_free(struct logfile_entry *entry)
+{
+       if (!entry) return;
+
+       if (entry->fd >= 0) close(entry->fd);
+       free(entry);
+}
+
+void logfile_free(struct logfile *f)
+{
+       if (!f) return;
+
+       logfile_entry_free(f->entry);
+
+       free(f->basepath);
+       free(f);
+}
+
+static struct logfile_entry *logfile_entry_new(const char *path, mode_t mode)
+{
+       struct logfile_entry *entry;
+       struct stat sb;
+
+       entry = calloc(1, sizeof(*entry));
+       if (!entry) goto err;
+
+       entry->fd = open(path, O_CREAT|O_APPEND|O_WRONLY|O_CLOEXEC, mode);
+       if (entry->fd < 0) {
+               dolog(LOG_ERR, "Failed to open log file %s", path);
+               goto err;
+       }
+
+       entry->pos = lseek(entry->fd, 0, SEEK_END);
+       if (entry->pos == (off_t)-1) {
+               dolog(LOG_ERR, "Unable to determine current file offset in %s",
+                     path);
+               goto err;
+       }
+
+       if (fstat(entry->fd, &sb) < 0) {
+               dolog(LOG_ERR, "Unable to fstat current file %s", path);
+               goto err;
+       }
+
+       entry->len = sb.st_size;
+       return entry;
+
+err:
+       logfile_entry_free(entry);
+       return NULL;
+}
+
+struct logfile *logfile_new(const char *path, mode_t mode)
+{
+       struct logfile *logfile;
+
+       logfile = calloc(1, sizeof(*logfile));
+       if (!logfile) goto err;
+
+       logfile->basepath = strdup(path);
+       if (!logfile->basepath) {
+               dolog(LOG_ERR, "Failed to strdup %s", path);
+               goto err;
+       }
+
+       logfile->mode = mode;
+       logfile->maxlen = LOGFILE_MAX_SIZE;
+
+
+       logfile->entry = logfile_entry_new(logfile->basepath, mode);
+
+       if (!logfile->entry) goto err;
+
+       return logfile;
+err:
+       logfile_free(logfile);
+       return NULL;
+}
+
+static int logfile_rollover(struct logfile *file)
+{
+       struct logfile_entry *old = file->entry, *new = NULL;
+       char *this = NULL;
+       char *next = NULL;
+       unsigned i;
+
+       if (asprintf(&next, "%s.%u", file->basepath,
+                    LOGFILE_MAX_BACKUP_NUM) < 0) {
+               dolog(LOG_ERR, "Failed to asprintf %s.%u",
+                     file->basepath, LOGFILE_MAX_BACKUP_NUM);
+               goto err;
+       }
+
+       for (i = LOGFILE_MAX_BACKUP_NUM; i > 0; i--) {
+               if (i == 1) {
+                       this = strdup(file->basepath);
+                       if (!this) {
+                               dolog(LOG_ERR, "Failed to strdup %s",
+                                     file->basepath);
+                               goto err;
+                       }
+               } else {
+                       if (asprintf(&this, "%s.%u", file->basepath, i-1) < 0) {
+                               dolog(LOG_ERR, "Failed to asprintf %s.%u",
+                                     file->basepath, i-1);
+                               goto err;
+                       }
+               }
+
+               if (rename(this, next) < 0 && errno != ENOENT) {
+                       dolog(LOG_ERR, "Failed to rename %s to %s",
+                             this, next);
+                       goto err;
+               }
+
+               free(next);
+               next = this;
+               this = NULL;
+       }
+
+       new = logfile_entry_new(file->basepath, file->mode);
+       if (!new) goto err;
+
+       file->entry = new;
+       logfile_entry_free(old);
+
+       return 0;
+err:
+       free(this);
+       free(next);
+       return -1;
+}
+
+static ssize_t write_all(int fd, const char* buf, size_t len)
+{
+       ssize_t written = 0;
+       while (len) {
+               ssize_t r = write(fd, buf, len);
+               if (r < 0 && errno == EINTR)
+                       continue;
+               if (r < 0)
+                       return r;
+               len -= r;
+               buf += r;
+               written += r;
+       }
+
+       return written;
+}
+
+ssize_t logfile_append(struct logfile *file, const char *buf,
+                      size_t len)
+{
+       ssize_t ret = 0;
+
+       while (len) {
+               struct logfile_entry *entry = file->entry;
+               size_t towrite = len;
+               bool rollover = false;
+
+               if (entry->pos > file->maxlen) {
+                       rollover = true;
+                       towrite = 0;
+               } else if (entry->pos + towrite > file->maxlen) {
+                       towrite = file->maxlen - entry->pos;
+               }
+
+               if (towrite) {
+                       if (write_all(entry->fd, buf, towrite) != towrite) {
+                               dolog(LOG_ERR, "Unable to write file %s",
+                                     file->basepath);
+                               return -1;
+                       }
+
+                       len -= towrite;
+                       buf += towrite;
+                       ret += towrite;
+                       entry->pos += towrite;
+                       entry->len += towrite;
+               }
+
+               if ((entry->pos == file->maxlen && len) || rollover) {
+                       dolog(LOG_DEBUG, "Roll over %s (maxlen %zu)",
+                             file->basepath, file->maxlen);
+                       if (logfile_rollover(file))
+                               return -1;
+               }
+       }
+
+       return ret;
+}
+
+
+/*
+ * Local variables:
+ *  c-file-style: "linux"
+ *  indent-tabs-mode: t
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ *  tab-width: 8
+ * End:
+ */
diff --git a/tools/console/daemon/logfile.h b/tools/console/daemon/logfile.h
new file mode 100644
index 0000000..87f3c51
--- /dev/null
+++ b/tools/console/daemon/logfile.h
@@ -0,0 +1,57 @@
+/*
+ *  Copyright (C) Citrix 2016
+ *  Author(s): Wei Liu <wei.liu2@xxxxxxxxxx>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef XENCONSOLED_LOGFILE_H
+#define XENCONSOLED_LOGFILE_H
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define LOGFILE_MAX_BACKUP_NUM  5
+#define LOGFILE_MAX_SIZE        (1024*128)
+
+/* Append only abstraction for log file */
+struct logfile_entry {
+       int fd;
+       off_t pos;
+       off_t len;
+};
+
+struct logfile {
+       char *basepath;
+       mode_t mode;
+       off_t maxlen;
+       struct logfile_entry *entry;
+};
+
+struct logfile *logfile_new(const char *path, mode_t mode);
+void logfile_free(struct logfile *f);
+ssize_t logfile_append(struct logfile *file, const char *buf,
+                      size_t len);
+
+#endif /* XENCONSOLED_LOGFILE_H */
+
+/*
+ * Local variables:
+ *  c-file-style: "linux"
+ *  indent-tabs-mode: t
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ *  tab-width: 8
+ * End:
+ */
-- 
2.1.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel