+++ /dev/null
-/**
- * collectd - src/utils_tail.c
- * Copyright (C) 2007-2008 C-Ware, Inc.
- * Copyright (C) 2008 Florian Forster
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
- * Author:
- * Luke Heberling <lukeh at c-ware.com>
- * Florian Forster <octo at collectd.org>
- *
- * 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 *fh;
- struct stat stat;
-};
-
-static int cu_tail_reopen(cu_tail_t *obj) {
- int seek_end = 0;
- struct stat stat_buf = {0};
-
- int status = stat(obj->file, &stat_buf);
- if (status != 0) {
- P_ERROR("utils_tail: stat (%s) failed: %s", obj->file, STRERRNO);
- return -1;
- }
-
- /* The file is already open.. */
- if ((obj->fh != NULL) && (stat_buf.st_ino == obj->stat.st_ino)) {
- /* Seek to the beginning if file was truncated */
- if (stat_buf.st_size < obj->stat.st_size) {
- P_INFO("utils_tail: File `%s' was truncated.", obj->file);
- status = fseek(obj->fh, 0, SEEK_SET);
- if (status != 0) {
- P_ERROR("utils_tail: fseek (%s) failed: %s", obj->file, STRERRNO);
- fclose(obj->fh);
- obj->fh = NULL;
- return -1;
- }
- }
- memcpy(&obj->stat, &stat_buf, sizeof(struct stat));
- return 1;
- }
-
- /* Seek to the end if we re-open the same file again or the file opened
- * is the first at all or the first after an error */
- if ((obj->stat.st_ino == 0) || (obj->stat.st_ino == stat_buf.st_ino))
- seek_end = 1;
-
- FILE *fh = fopen(obj->file, "r");
- if (fh == NULL) {
- P_ERROR("utils_tail: fopen (%s) failed: %s", obj->file, STRERRNO);
- return -1;
- }
-
- if (seek_end != 0) {
- status = fseek(fh, 0, SEEK_END);
- if (status != 0) {
- P_ERROR("utils_tail: fseek (%s) failed: %s", obj->file, STRERRNO);
- fclose(fh);
- return -1;
- }
- }
-
- if (obj->fh != NULL)
- fclose(obj->fh);
- obj->fh = fh;
- memcpy(&obj->stat, &stat_buf, sizeof(struct stat));
-
- return 0;
-} /* int cu_tail_reopen */
-
-cu_tail_t *cu_tail_create(const char *file) {
- cu_tail_t *obj;
-
- obj = calloc(1, sizeof(*obj));
- if (obj == NULL)
- return NULL;
-
- obj->file = strdup(file);
- if (obj->file == NULL) {
- free(obj);
- return NULL;
- }
-
- obj->fh = NULL;
-
- return obj;
-} /* cu_tail_t *cu_tail_create */
-
-int cu_tail_destroy(cu_tail_t *obj) {
- if (obj->fh != NULL)
- fclose(obj->fh);
- free(obj->file);
- free(obj);
-
- return 0;
-} /* int cu_tail_destroy */
-
-int cu_tail_readline(cu_tail_t *obj, char *buf, int buflen) {
- int status;
-
- if (buflen < 1) {
- ERROR("utils_tail: cu_tail_readline: buflen too small: %i bytes.", buflen);
- return -1;
- }
-
- if (obj->fh == NULL) {
- status = cu_tail_reopen(obj);
- if (status < 0)
- return status;
- }
- assert(obj->fh != NULL);
-
- /* Try to read from the filehandle. If that succeeds, everything appears to
- * be fine and we can return. */
- clearerr(obj->fh);
- if (fgets(buf, buflen, obj->fh) != NULL) {
- buf[buflen - 1] = 0;
- return 0;
- }
-
- /* Check if we encountered an error */
- if (ferror(obj->fh) != 0) {
- /* Jupp, error. Force `cu_tail_reopen' to reopen the file.. */
- fclose(obj->fh);
- obj->fh = NULL;
- }
- /* else: eof -> check if the file was moved away and reopen the new file if
- * so.. */
-
- status = cu_tail_reopen(obj);
- /* error -> return with error */
- if (status < 0)
- return status;
- /* file end reached and file not reopened -> nothing more to read */
- else if (status > 0) {
- buf[0] = 0;
- return 0;
- }
-
- /* If we get here: file was re-opened and there may be more to read.. Let's
- * try again. */
- if (fgets(buf, buflen, obj->fh) != NULL) {
- buf[buflen - 1] = 0;
- return 0;
- }
-
- if (ferror(obj->fh) != 0) {
- WARNING("utils_tail: fgets (%s) returned an error: %s", obj->file,
- STRERRNO);
- fclose(obj->fh);
- obj->fh = NULL;
- return -1;
- }
-
- /* EOf, well, apparently the new file is empty.. */
- buf[0] = 0;
- return 0;
-} /* int cu_tail_readline */
-
-int cu_tail_read(cu_tail_t *obj, char *buf, int buflen, tailfunc_t *callback,
- void *data) {
- int status;
-
- while (42) {
- size_t len;
-
- status = cu_tail_readline(obj, buf, buflen);
- if (status != 0) {
- ERROR("utils_tail: cu_tail_read: cu_tail_readline "
- "failed.");
- break;
- }
-
- /* check for EOF */
- if (buf[0] == 0)
- break;
-
- len = strlen(buf);
- while (len > 0) {
- if (buf[len - 1] != '\n')
- break;
- buf[len - 1] = '\0';
- len--;
- }
-
- status = callback(data, buf, buflen);
- if (status != 0) {
- ERROR("utils_tail: cu_tail_read: callback returned "
- "status %i.",
- status);
- break;
- }
- }
-
- return status;
-} /* int cu_tail_read */
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