--- /dev/null
+/**
+ * collectd - src/utils_tail.c
+ * Copyright (C) 2007-2008 C-Ware, Inc.
+ *
+ * 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; only version 2 of the License is applicable.
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Author:
+ * Luke Heberling <lukeh at c-ware.com>
+ *
+ * Description:
+ * Encapsulates useful code for plugins which must watch for appends to
+ * the end of a file.
+ **/
+
+#include "collectd.h"
+#include "common.h"
+#include "utils_tail.h"
+
+struct cu_tail_s
+{
+ char *file;
+ FILE *fd;
+ struct stat stat;
+};
+
+cu_tail_t *cu_tail_create (const char *file)
+{
+ cu_tail_t *obj;
+
+ obj = (cu_tail_t *) malloc (sizeof (cu_tail_t));
+ if (obj == NULL)
+ return (NULL);
+ memset (obj, '\0', sizeof (cu_tail_t));
+
+ obj->file = strdup (file);
+ if (obj->file == NULL)
+ {
+ free (obj);
+ return (NULL);
+ }
+
+ obj->fd = NULL;
+
+ return (obj);
+} /* cu_tail_t *cu_tail_create */
+
+int cu_tail_destroy (cu_tail_t *obj)
+{
+ if (obj->fd != NULL)
+ fclose (obj->fd);
+ free (obj->file);
+ free (obj);
+
+ return (0);
+} /* int cu_tail_destroy */
+
+int cu_tail_readline (cu_tail_t *obj, char *buf, int buflen)
+{
+ struct stat stat_now;
+ int status;
+
+ if (buflen < 1)
+ return (-1);
+
+ if (stat (obj->file, &stat_now) != 0)
+ {
+ char errbuf[1024];
+ ERROR ("cu_tail_readline: stat (%s) failed: %s",
+ obj->file,
+ sstrerror (errno, errbuf, sizeof (errbuf)));
+ return (-1);
+ }
+
+ if ((stat_now.st_dev != obj->stat.st_dev) ||
+ (stat_now.st_ino != obj->stat.st_ino))
+ {
+ /*
+ * If the file was replaced open the new file and close the
+ * old filehandle
+ */
+ FILE *new_fd;
+
+ new_fd = fopen (obj->file, "r");
+ if (new_fd == NULL)
+ {
+ char errbuf[1024];
+ ERROR ("cu_tail_readline: open (%s) failed: %s",
+ obj->file,
+ sstrerror (errno, errbuf,
+ sizeof (errbuf)));
+ return (-1);
+ }
+
+ /* If there was no previous file, seek to the end. We don't
+ * want to read in the entire file, usually. */
+ if (obj->stat.st_ino == 0)
+ fseek (new_fd, 0, SEEK_END);
+
+ if (obj->fd != NULL)
+ fclose (obj->fd);
+ obj->fd = new_fd;
+
+ }
+ else if (stat_now.st_size < obj->stat.st_size)
+ {
+ /*
+ * Else, if the file was not replaces, but the file was
+ * truncated, seek to the beginning of the file.
+ */
+ assert (obj->fd != NULL);
+ rewind (obj->fd);
+ }
+
+ status = 0;
+ if (fgets (buf, buflen, obj->fd) == NULL)
+ {
+ if (feof (obj->fd) == 0)
+ buf[0] = '\0';
+ else /* an error occurred */
+ status = -1;
+ }
+
+ if (status == 0)
+ memcpy (&obj->stat, &stat_now, sizeof (struct stat));
+
+ return (status);
+} /* int cu_tail_readline */
+
+int cu_tail_read (cu_tail_t *obj, char *buf, int buflen, tailfunc *callback,
+ void *data)
+{
+ int status;
+
+ while ((status = cu_tail_readline (obj, buf, buflen)) == 0)
+ {
+ /* check for EOF */
+ if (buf[0] == '\0')
+ break;
+
+ status = callback (data, buf, buflen);
+ if (status != 0)
+ break;
+ }
+
+ return status;
+} /* int cu_tail_read */
--- /dev/null
+/**
+ * collectd - src/utils_tail.h
+ * Copyright (C) 2007-2008 C-Ware, Inc.
+ *
+ * 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; only version 2 of the License is applicable.
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Author:
+ * Luke Heberling <lukeh at c-ware.com>
+ *
+ * DESCRIPTION
+ * Facilitates reading information that is appended to a file, taking into
+ * account that the file may be rotated and a new file created under the
+ * same name.
+ **/
+
+#ifndef UTILS_TAIL_H
+#define UTILS_TAIL_H 1
+
+struct cu_tail_s;
+typedef struct cu_tail_s cu_tail_t;
+
+typedef int tailfunc(void *data, char *buf, int buflen);
+
+/*
+ * NAME
+ * cu_tail_create
+ *
+ * DESCRIPTION
+ * Allocates a new tail object..
+ *
+ * PARAMETERS
+ * `file' The name of the file to be tailed.
+ */
+cu_tail_t *cu_tail_create (const char *file);
+
+/*
+ * cu_tail_destroy
+ *
+ * Takes a tail object returned by `cu_tail_create' and destroys it, freeing
+ * all internal memory.
+ *
+ * Returns 0 when successful and non-zero otherwise.
+ */
+int cu_tail_destroy (cu_tail_t *obj);
+
+/*
+ * cu_tail_readline
+ *
+ * Reads from the file until `buflen' characters are read, a newline
+ * character is read, or an eof condition is encountered. `buf' is
+ * always null-terminated on successful return and isn't touched when non-zero
+ * is returned.
+ *
+ * You can check if the EOF condition is reached by looking at the buffer: If
+ * the length of the string stored in the buffer is zero, EOF occurred.
+ * Otherwise at least the newline character will be in the buffer.
+ *
+ * Returns 0 when successful and non-zero otherwise.
+ */
+int cu_tail_readline (cu_tail_t *obj, char *buf, int buflen);
+
+/*
+ * cu_tail_readline
+ *
+ * Reads from the file until eof condition or an error is encountered.
+ *
+ * Returns 0 when successful and non-zero otherwise.
+ */
+int cu_tail_read (cu_tail_t *obj, char *buf, int buflen, tailfunc *callback,
+ void *data);
+
+#endif /* UTILS_TAIL_H */
projects / collectd.git / commitdiff