X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Futils_tail.c;h=565a224c920df8f661488f17a8bd96e8cfb2245a;hb=446138394bb95c49d0e05ea440fbf63aefe84bab;hp=58e027e4f2ff565fa81a2dc549cb94e6e01c4ddd;hpb=a813e8af8379bd0f55a2b46fc7918fa31de9522e;p=collectd.git diff --git a/src/utils_tail.c b/src/utils_tail.c index 58e027e4..565a224c 100644 --- a/src/utils_tail.c +++ b/src/utils_tail.c @@ -1,22 +1,29 @@ /** * collectd - src/utils_tail.c * Copyright (C) 2007-2008 C-Ware, Inc. + * Copyright (C) 2008 Florian Forster * - * 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. + * 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: * - * 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. + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. * - * 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 + * 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 + * Florian Forster * * Description: * Encapsulates useful code for plugins which must watch for appends to @@ -24,157 +31,205 @@ **/ #include "collectd.h" + #include "common.h" #include "utils_tail.h" -struct cu_tail_s -{ - char *file; - FILE *fd; - struct stat stat; +struct cu_tail_s { + char *file; + FILE *fh; + 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); +static int cu_tail_reopen(cu_tail_t *obj) { + int seek_end = 0; + FILE *fh; + struct stat stat_buf = {0}; + int status; + + status = stat(obj->file, &stat_buf); + if (status != 0) { + char errbuf[1024]; + ERROR("utils_tail: stat (%s) failed: %s", obj->file, + sstrerror(errno, errbuf, sizeof(errbuf))); + 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) { + INFO("utils_tail: File `%s' was truncated.", obj->file); + status = fseek(obj->fh, 0, SEEK_SET); + if (status != 0) { + char errbuf[1024]; + ERROR("utils_tail: fseek (%s) failed: %s", obj->file, + sstrerror(errno, errbuf, sizeof(errbuf))); + 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; + + fh = fopen(obj->file, "r"); + if (fh == NULL) { + char errbuf[1024]; + ERROR("utils_tail: fopen (%s) failed: %s", obj->file, + sstrerror(errno, errbuf, sizeof(errbuf))); + return (-1); + } + + if (seek_end != 0) { + status = fseek(fh, 0, SEEK_END); + if (status != 0) { + char errbuf[1024]; + ERROR("utils_tail: fseek (%s) failed: %s", obj->file, + sstrerror(errno, errbuf, sizeof(errbuf))); + 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->fd != NULL) - fclose (obj->fd); - free (obj->file); - free (obj); +int cu_tail_destroy(cu_tail_t *obj) { + if (obj->fh != NULL) + fclose(obj->fh); + free(obj->file); + free(obj); - return (0); + 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) - { - ERROR ("utils_tail: cu_tail_readline: buflen too small: " - "%i bytes.", buflen); - 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; - - DEBUG ("utils_tail: cu_tail_readline: (Re)Opening %s..", - obj->file); - - new_fd = fopen (obj->file, "r"); - if (new_fd == NULL) - { - char errbuf[1024]; - ERROR ("utils_tail: 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 */ - { - ERROR ("utils_tail: cu_tail_readline: fgets returned " - "an error."); - status = -1; - } - } - - if (status == 0) - memcpy (&obj->stat, &stat_now, sizeof (struct stat)); - - return (status); +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) { + char errbuf[1024]; + WARNING("utils_tail: fgets (%s) returned an error: %s", obj->file, + sstrerror(errno, errbuf, sizeof(errbuf))); + 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) - { - 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; - - 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(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 */