diff options
Diffstat (limited to 'pw/fileupd.c')
| -rw-r--r-- | pw/fileupd.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/pw/fileupd.c b/pw/fileupd.c new file mode 100644 index 0000000..b88f4fa --- /dev/null +++ b/pw/fileupd.c @@ -0,0 +1,203 @@ +/*- + * Copyright (C) 1996 + * David L. Nugent. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef lint +static const char rcsid[] = + "$FreeBSD$"; +#endif /* not lint */ + +#include <stdio.h> +#include <fcntl.h> +#include <stdlib.h> +#include <string.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/param.h> +#include <errno.h> +#include <unistd.h> + +#include "pwupd.h" + +int +extendline(char **buf, int * buflen, int needed) +{ + if (needed > *buflen) { + char *tmp = realloc(*buf, needed); + if (tmp == NULL) + return -1; + *buf = tmp; + *buflen = needed; + } + return *buflen; +} + +int +extendarray(char ***buf, int * buflen, int needed) +{ + if (needed > *buflen) { + char **tmp = realloc(*buf, needed * sizeof(char *)); + if (tmp == NULL) + return -1; + *buf = tmp; + *buflen = needed; + } + return *buflen; +} + + +int +fileupdate(char const * filename, mode_t fmode, char const * newline, char const * prefix, int pfxlen, int updmode) +{ + int rc = 0; + + if (pfxlen <= 1) + rc = EINVAL; + else { + int infd = open(filename, O_RDWR | O_CREAT | O_EXLOCK, fmode); + + if (infd == -1) + rc = errno; + else { + FILE *infp = fdopen(infd, "r+"); + + if (infp == NULL) { + rc = errno; /* Assumes fopen(3) sets errno from open(2) */ + close(infd); + } else { + int outfd; + char file[MAXPATHLEN]; + + strcpy(file, filename); + strcat(file, ".new"); + outfd = open(file, O_RDWR | O_CREAT | O_TRUNC, fmode); + if (outfd == -1) + rc = errno; + else { + FILE *outfp = fdopen(outfd, "w+"); + + if (outfp == NULL) { + rc = errno; + close(outfd); + } else { + int updated = UPD_CREATE; + int linesize = PWBUFSZ; + char *line = malloc(linesize); + + nextline: + while (fgets(line, linesize, infp) != NULL) { + char *p = strchr(line, '\n'); + + while ((p = strchr(line, '\n')) == NULL) { + int l; + if (extendline(&line, &linesize, linesize + PWBUFSZ) == -1) { + int ch; + fputs(line, outfp); + while ((ch = fgetc(infp)) != EOF) { + fputc(ch, outfp); + if (ch == '\n') + break; + } + goto nextline; + } + l = strlen(line); + if (fgets(line + l, linesize - l, infp) == NULL) + break; + } + if (*line != '#' && *line != '\n') { + if (!updated && strncmp(line, prefix, pfxlen) == 0) { + updated = updmode == UPD_REPLACE ? UPD_REPLACE : UPD_DELETE; + + /* + * Only actually write changes if updating + */ + if (updmode == UPD_REPLACE) + strcpy(line, newline); + else if (updmode == UPD_DELETE) + continue; + } + } + fputs(line, outfp); + } + + /* + * Now, we need to decide what to do: If we are in + * update mode, and no record was updated, then error If + * we are in insert mode, and record already exists, + * then error + */ + if (updmode != updated) + /* -1 return means: + * update,delete=no user entry + * create=entry exists + */ + rc = -1; + else { + + /* + * If adding a new record, append it to the end + */ + if (updmode == UPD_CREATE) + fputs(newline, outfp); + + /* + * Flush the file and check for the result + */ + if (fflush(outfp) == EOF) + rc = errno; /* Failed to update */ + else { + /* + * Copy data back into the + * original file and truncate + */ + rewind(infp); + rewind(outfp); + while (fgets(line, linesize, outfp) != NULL) + fputs(line, infp); + + /* + * If there was a problem with copying + * we will just rename 'file.new' + * to 'file'. + * This is a gross hack, but we may have + * corrupted the original file + */ + if (fflush(infp) == EOF || ferror(infp)) + rename(file, filename); + else + ftruncate(infd, ftell(infp)); + } + } + free(line); + fclose(outfp); + } + remove(file); + } + fclose(infp); + } + } + } + return rc; +} |