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/* * Copyright (c) 1987 Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms are permitted * provided that: (1) source distributions retain this entire copyright * notice and comment, and (2) distributions including binaries display * the following acknowledgement: ``This product includes software * developed by the University of California, Berkeley and its contributors'' * in the documentation or other materials provided with the distribution * and in all advertising materials mentioning features or use of this * software. Neither the name of the University nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ /* This is file MKTEMP.C */ /* This file may have been modified by DJ Delorie (Jan 1991). If so, ** these modifications are Copyright (C) 1991 DJ Delorie. */ /* FUNCTION <<mktemp>>, <<mkstemp>>, <<mkstemps>>---generate unused file name <<mkdtemp>>---generate unused directory INDEX mktemp INDEX mkdtemp INDEX mkstemp INDEX mkstemps INDEX _mktemp_r INDEX _mkdtemp_r INDEX _mkstemp_r INDEX _mkstemps_r ANSI_SYNOPSIS #include <stdlib.h> char *mktemp(char *<[path]>); char *mkdtemp(char *<[path]>); int mkstemp(char *<[path]>); int mkstemps(char *<[path]>, int <[suffixlen]>); char *_mktemp_r(struct _reent *<[reent]>, char *<[path]>); char *_mkdtemp_r(struct _reent *<[reent]>, char *<[path]>); int *_mkstemp_r(struct _reent *<[reent]>, char *<[path]>); int *_mkstemps_r(struct _reent *<[reent]>, char *<[path]>, int <[len]>); DESCRIPTION <<mktemp>>, <<mkstemp>>, and <<mkstemps>> attempt to generate a file name that is not yet in use for any existing file. <<mkstemp>> and <<mkstemps>> create the file and open it for reading and writing; <<mktemp>> simply generates the file name (making <<mktemp>> a security risk). <<mkdtemp>> attempts to create a directory instead of a file, with a permissions mask of 0700. You supply a simple pattern for the generated file name, as the string at <[path]>. The pattern should be a valid filename (including path information if you wish) ending with at least six `<<X>>' characters. The generated filename will match the leading part of the name you supply, with the trailing `<<X>>' characters replaced by some combination of digits and letters. With <<mkstemps>>, the `<<X>>' characters end <[suffixlen]> bytes before the end of the string. The alternate functions <<_mktemp_r>>, <<_mkdtemp_r>>, <<_mkstemp_r>>, and <<_mkstemps_r>> are reentrant versions. The extra argument <[reent]> is a pointer to a reentrancy structure. RETURNS <<mktemp>> returns the pointer <[path]> to the modified string representing an unused filename, unless it could not generate one, or the pattern you provided is not suitable for a filename; in that case, it returns <<NULL>>. <<mkdtemp>> returns the pointer <[path]> to the modified string if the directory was created, otherwise it returns <<NULL>>. <<mkstemp>> and <<mkstemps>> return a file descriptor to the newly created file, unless it could not generate an unused filename, or the pattern you provided is not suitable for a filename; in that case, it returns <<-1>>. NOTES Never use <<mktemp>>. The generated filenames are easy to guess and there's a race between the test if the file exists and the creation of the file. In combination this makes <<mktemp>> prone to attacks and using it is a security risk. Whenever possible use <<mkstemp>> instead. It doesn't suffer the race condition. PORTABILITY ANSI C does not require either <<mktemp>> or <<mkstemp>>; the System V Interface Definition requires <<mktemp>> as of Issue 2. POSIX 2001 requires <<mkstemp>>, and POSIX 2008 requires <<mkdtemp>>, but <<mkstemps>> is not standardized. Supporting OS subroutines required: <<getpid>>, <<mkdir>>, <<open>>, <<stat>>. */ #include <_ansi.h> #include <stdlib.h> #include <reent.h> #include <sys/types.h> #include <fcntl.h> #include <sys/stat.h> #include <errno.h> #include <stdio.h> #include <ctype.h> static int _DEFUN(_gettemp, (ptr, path, doopen, domkdir, suffixlen), struct _reent *ptr _AND char *path _AND register int *doopen _AND int domkdir _AND size_t suffixlen) { register char *start, *trv; char *end; #ifdef __USE_INTERNAL_STAT64 struct stat64 sbuf; #else struct stat sbuf; #endif unsigned int pid; pid = _getpid_r (ptr); for (trv = path; *trv; ++trv) /* extra X's get set to 0's */ continue; if (trv - path < suffixlen) { ptr->_errno = EINVAL; return 0; } trv -= suffixlen; end = trv; while (path < trv && *--trv == 'X') { *trv = (pid % 10) + '0'; pid /= 10; } if (end - trv < 6) { ptr->_errno = EINVAL; return 0; } /* * Check the target directory; if you have six X's and it * doesn't exist this runs for a *very* long time. */ for (start = trv + 1;; --trv) { if (trv <= path) break; if (*trv == '/') { *trv = '\0'; #ifdef __USE_INTERNAL_STAT64 if (_stat64_r (ptr, path, &sbuf)) #else if (_stat_r (ptr, path, &sbuf)) #endif return (0); if (!(sbuf.st_mode & S_IFDIR)) { ptr->_errno = ENOTDIR; return (0); } *trv = '/'; break; } } for (;;) { #if !defined _ELIX_LEVEL || _ELIX_LEVEL >= 4 if (domkdir) { #ifdef HAVE_MKDIR if (_mkdir_r (ptr, path, 0700) == 0) return 1; if (ptr->_errno != EEXIST) return 0; #else /* !HAVE_MKDIR */ ptr->_errno = ENOSYS; return 0; #endif /* !HAVE_MKDIR */ } else #endif /* _ELIX_LEVEL */ if (doopen) { if ((*doopen = _open_r (ptr, path, O_CREAT | O_EXCL | O_RDWR, 0600)) >= 0) return 1; if (ptr->_errno != EEXIST) return 0; } #ifdef __USE_INTERNAL_STAT64 else if (_stat64_r (ptr, path, &sbuf)) #else else if (_stat_r (ptr, path, &sbuf)) #endif return (ptr->_errno == ENOENT ? 1 : 0); /* tricky little algorithm for backward compatibility */ for (trv = start;;) { if (trv == end) return 0; if (*trv == 'z') *trv++ = 'a'; else { /* Safe, since it only encounters 7-bit characters. */ if (isdigit (*trv)) *trv = 'a'; else ++ * trv; break; } } } /*NOTREACHED*/ } int _DEFUN(_mkstemp_r, (ptr, path), struct _reent *ptr _AND char *path) { int fd; return (_gettemp (ptr, path, &fd, 0, 0) ? fd : -1); } #if !defined _ELIX_LEVEL || _ELIX_LEVEL >= 4 char * _DEFUN(_mkdtemp_r, (ptr, path), struct _reent *ptr _AND char *path) { return (_gettemp (ptr, path, (int *) NULL, 1, 0) ? path : NULL); } int _DEFUN(_mkstemps_r, (ptr, path, len), struct _reent *ptr _AND char *path _AND int len) { int fd; return (_gettemp (ptr, path, &fd, 0, len) ? fd : -1); } #endif /* _ELIX_LEVEL */ char * _DEFUN(_mktemp_r, (ptr, path), struct _reent *ptr _AND char *path) { return (_gettemp (ptr, path, (int *) NULL, 0, 0) ? path : (char *) NULL); } #ifndef _REENT_ONLY int _DEFUN(mkstemp, (path), char *path) { int fd; return (_gettemp (_REENT, path, &fd, 0, 0) ? fd : -1); } # if !defined _ELIX_LEVEL || _ELIX_LEVEL >= 4 char * _DEFUN(mkdtemp, (path), char *path) { return (_gettemp (_REENT, path, (int *) NULL, 1, 0) ? path : NULL); } int _DEFUN(mkstemps, (path, len), char *path _AND int len) { int fd; return (_gettemp (_REENT, path, &fd, 0, len) ? fd : -1); } # endif /* _ELIX_LEVEL */ char * _DEFUN(mktemp, (path), char *path) { return (_gettemp (_REENT, path, (int *) NULL, 0, 0) ? path : (char *) NULL); } #endif /* ! defined (_REENT_ONLY) */