154 lines
4.3 KiB
C
154 lines
4.3 KiB
C
/*-
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* Copyright (C) 1996
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* David L. Nugent. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: fileupd.c,v 1.1.1.1 1996/12/09 14:05:35 joerg Exp $
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*/
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#include <stdio.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/param.h>
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#include <errno.h>
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#include <unistd.h>
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#include "pwupd.h"
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int
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fileupdate(char const * filename, mode_t fmode, char const * newline, char const * prefix, int pfxlen, int updmode)
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{
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int rc = 0;
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if (pfxlen <= 1)
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errno = EINVAL;
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else {
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int infd = open(filename, O_RDWR | O_CREAT | O_EXLOCK, fmode);
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if (infd != -1) {
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FILE *infp = fdopen(infd, "r+");
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if (infp == NULL)
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close(infd);
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else {
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int outfd;
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char file[MAXPATHLEN];
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strcpy(file, filename);
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strcat(file, ".new");
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outfd = open(file, O_RDWR | O_CREAT | O_TRUNC | O_EXLOCK, fmode);
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if (outfd != -1) {
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FILE *outfp = fdopen(outfd, "w+");
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if (outfp == NULL)
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close(outfd);
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else {
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int updated = UPD_CREATE;
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char line[2048];
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while (fgets(line, sizeof(line), infp) != NULL) {
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char *p = strchr(line, '\n');
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if (p == NULL) { /* Line too long */
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int ch;
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fputs(line, outfp);
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while ((ch = fgetc(infp)) != EOF) {
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fputc(ch, outfp);
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if (ch == '\n')
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break;
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}
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continue;
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}
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if (*line != '#' && *line != '\n') {
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if (!updated && strncmp(line, prefix, pfxlen) == 0) {
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updated = updmode == UPD_REPLACE ? UPD_REPLACE : UPD_DELETE;
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/*
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* Only actually write changes if updating
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*/
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if (updmode == UPD_REPLACE)
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strcpy(line, newline);
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else if (updmode == UPD_DELETE)
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continue;
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}
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}
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fputs(line, outfp);
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}
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/*
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* Now, we need to decide what to do: If we are in
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* update mode, and no record was updated, then error If
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* we are in insert mode, and record already exists,
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* then error
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*/
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if (updmode != updated)
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errno = (updmode == UPD_CREATE) ? EEXIST : ENOENT;
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else {
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/*
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* If adding a new record, append it to the end
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*/
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if (updmode == UPD_CREATE)
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fputs(newline, outfp);
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/*
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* Flush the file and check for the result
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*/
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rc = fflush(outfp) != EOF;
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if (rc) {
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/*
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* Copy data back into the
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* original file and truncate
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*/
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rewind(infp);
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rewind(outfp);
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while (fgets(line, sizeof(line), outfp) != NULL)
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fputs(line, infp);
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/*
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* This is a gross hack, but we may have
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* corrupted the original file
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* Unfortunately, it will lose the inode.
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*/
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if (fflush(infp) == EOF || ferror(infp))
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rc = rename(file, filename) == 0;
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else
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ftruncate(infd, ftell(infp));
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}
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}
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fclose(outfp);
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}
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remove(file);
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}
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fclose(infp);
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}
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}
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}
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return rc;
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}
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