fileupd.c revision 20302
120253Sjoerg/*- 220302Sjoerg * Copyright (C) 1996 320302Sjoerg * David L. Nugent. All rights reserved. 420253Sjoerg * 520253Sjoerg * Redistribution and use in source and binary forms, with or without 620253Sjoerg * modification, are permitted provided that the following conditions 720253Sjoerg * are met: 820253Sjoerg * 1. Redistributions of source code must retain the above copyright 920302Sjoerg * notice, this list of conditions and the following disclaimer. 1020253Sjoerg * 2. Redistributions in binary form must reproduce the above copyright 1120253Sjoerg * notice, this list of conditions and the following disclaimer in the 1220253Sjoerg * documentation and/or other materials provided with the distribution. 1320253Sjoerg * 1420302Sjoerg * THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND 1520253Sjoerg * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1620253Sjoerg * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1720302Sjoerg * ARE DISCLAIMED. IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE 1820253Sjoerg * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1920253Sjoerg * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2020253Sjoerg * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2120253Sjoerg * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2220253Sjoerg * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2320253Sjoerg * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2420253Sjoerg * SUCH DAMAGE. 2520253Sjoerg * 2620302Sjoerg * $Id: fileupd.c,v 1.1.1.1 1996/12/09 14:05:35 joerg Exp $ 2720253Sjoerg */ 2820253Sjoerg 2920253Sjoerg#include <stdio.h> 3020253Sjoerg#include <fcntl.h> 3120253Sjoerg#include <stdlib.h> 3220253Sjoerg#include <string.h> 3320253Sjoerg#include <sys/types.h> 3420253Sjoerg#include <sys/stat.h> 3520253Sjoerg#include <sys/param.h> 3620253Sjoerg#include <errno.h> 3720253Sjoerg#include <unistd.h> 3820253Sjoerg 3920253Sjoerg#include "pwupd.h" 4020253Sjoerg 4120253Sjoergint 4220253Sjoergfileupdate(char const * filename, mode_t fmode, char const * newline, char const * prefix, int pfxlen, int updmode) 4320253Sjoerg{ 4420253Sjoerg int rc = 0; 4520253Sjoerg 4620253Sjoerg if (pfxlen <= 1) 4720253Sjoerg errno = EINVAL; 4820253Sjoerg else { 4920253Sjoerg int infd = open(filename, O_RDWR | O_CREAT | O_EXLOCK, fmode); 5020253Sjoerg 5120253Sjoerg if (infd != -1) { 5220253Sjoerg FILE *infp = fdopen(infd, "r+"); 5320253Sjoerg 5420253Sjoerg if (infp == NULL) 5520253Sjoerg close(infd); 5620253Sjoerg else { 5720253Sjoerg int outfd; 5820253Sjoerg char file[MAXPATHLEN]; 5920253Sjoerg 6020253Sjoerg strcpy(file, filename); 6120253Sjoerg strcat(file, ".new"); 6220253Sjoerg outfd = open(file, O_RDWR | O_CREAT | O_TRUNC | O_EXLOCK, fmode); 6320253Sjoerg if (outfd != -1) { 6420253Sjoerg FILE *outfp = fdopen(outfd, "w+"); 6520253Sjoerg 6620253Sjoerg if (outfp == NULL) 6720253Sjoerg close(outfd); 6820253Sjoerg else { 6920253Sjoerg int updated = UPD_CREATE; 7020253Sjoerg char line[2048]; 7120253Sjoerg 7220253Sjoerg while (fgets(line, sizeof(line), infp) != NULL) { 7320253Sjoerg char *p = strchr(line, '\n'); 7420253Sjoerg 7520253Sjoerg if (p == NULL) { /* Line too long */ 7620253Sjoerg int ch; 7720253Sjoerg 7820253Sjoerg fputs(line, outfp); 7920253Sjoerg while ((ch = fgetc(infp)) != EOF) { 8020253Sjoerg fputc(ch, outfp); 8120253Sjoerg if (ch == '\n') 8220253Sjoerg break; 8320253Sjoerg } 8420253Sjoerg continue; 8520253Sjoerg } 8620253Sjoerg if (*line != '#' && *line != '\n') { 8720253Sjoerg if (!updated && strncmp(line, prefix, pfxlen) == 0) { 8820253Sjoerg updated = updmode == UPD_REPLACE ? UPD_REPLACE : UPD_DELETE; 8920253Sjoerg 9020253Sjoerg /* 9120253Sjoerg * Only actually write changes if updating 9220253Sjoerg */ 9320253Sjoerg if (updmode == UPD_REPLACE) 9420253Sjoerg strcpy(line, newline); 9520253Sjoerg else if (updmode == UPD_DELETE) 9620253Sjoerg continue; 9720253Sjoerg } 9820253Sjoerg } 9920253Sjoerg fputs(line, outfp); 10020253Sjoerg } 10120253Sjoerg 10220253Sjoerg /* 10320253Sjoerg * Now, we need to decide what to do: If we are in 10420253Sjoerg * update mode, and no record was updated, then error If 10520253Sjoerg * we are in insert mode, and record already exists, 10620253Sjoerg * then error 10720253Sjoerg */ 10820253Sjoerg if (updmode != updated) 10920253Sjoerg errno = (updmode == UPD_CREATE) ? EEXIST : ENOENT; 11020253Sjoerg else { 11120253Sjoerg 11220253Sjoerg /* 11320253Sjoerg * If adding a new record, append it to the end 11420253Sjoerg */ 11520253Sjoerg if (updmode == UPD_CREATE) 11620253Sjoerg fputs(newline, outfp); 11720253Sjoerg 11820253Sjoerg /* 11920253Sjoerg * Flush the file and check for the result 12020253Sjoerg */ 12120253Sjoerg rc = fflush(outfp) != EOF; 12220253Sjoerg if (rc) { 12320253Sjoerg 12420253Sjoerg /* 12520253Sjoerg * Copy data back into the 12620253Sjoerg * original file and truncate 12720253Sjoerg */ 12820253Sjoerg rewind(infp); 12920253Sjoerg rewind(outfp); 13020253Sjoerg while (fgets(line, sizeof(line), outfp) != NULL) 13120253Sjoerg fputs(line, infp); 13220253Sjoerg 13320253Sjoerg /* 13420253Sjoerg * This is a gross hack, but we may have 13520253Sjoerg * corrupted the original file 13620253Sjoerg * Unfortunately, it will lose the inode. 13720253Sjoerg */ 13820253Sjoerg if (fflush(infp) == EOF || ferror(infp)) 13920253Sjoerg rc = rename(file, filename) == 0; 14020253Sjoerg else 14120253Sjoerg ftruncate(infd, ftell(infp)); 14220253Sjoerg } 14320253Sjoerg } 14420253Sjoerg fclose(outfp); 14520253Sjoerg } 14620253Sjoerg remove(file); 14720253Sjoerg } 14820253Sjoerg fclose(infp); 14920253Sjoerg } 15020253Sjoerg } 15120253Sjoerg } 15220253Sjoerg return rc; 15320253Sjoerg} 154