pith/osdep/temp_nam.c

   1 #if !defined(lint) && !defined(DOS)
   2 static char rcsid[] = "$Id: temp_nam.c 1012 2008-03-26 00:44:22Z hubert@u.washington.edu $";
   3 #endif
   4
   5 /*
   6  * ========================================================================
   7  * Copyright 2006-2008 University of Washington
   8  * Copyright 2013-2020 Eduardo Chappa
   9  *
  10  * Licensed under the Apache License, Version 2.0 (the "License");
  11  * you may not use this file except in compliance with the License.
  12  * You may obtain a copy of the License at
  13  *
  14  *     http://www.apache.org/licenses/LICENSE-2.0
  15  *
  16  * ========================================================================
  17  */
  18
  19 #include <system.h>
  20
  21 #if     HAVE_FCNTL_H
  22 #include <fcntl.h>
  23 #endif
  24
  25 #include "canaccess.h"
  26 #include "temp_nam.h"
  27 #include "../charconv/utf8.h"
  28 #include "../charconv/filesys.h"
  29
  30
  31 #ifdef  _WINDOWS
  32
  33 #include <process.h>
  34
  35 #define ACCESSIBLE      (WRITE_ACCESS)
  36 #define PATH_SEP        "\\"
  37
  38 #else  /* UNIX */
  39
  40 #define ACCESSIBLE      (WRITE_ACCESS|EXECUTE_ACCESS)
  41 #define PATH_SEP        "/"
  42
  43 #endif /* UNIX */
  44
  45
  46 /*
  47  * Internal Prototypes
  48  */
  49 char    *was_nonexistent_tmp_name(char *, size_t, char *);
  50
  51
  52
  53 /*
  54  * This routine is derived from BSD4.3 code,
  55  * Copyright (c) 1987 Regents of the University of California.
  56  * All rights reserved.
  57  */
  58 #if defined(LIBC_SCCS) && !defined(lint)
  59 static char sccsid[] = "@(#)mktemp.c    5.7 (Berkeley) 6/27/88";
  60 #endif /* LIBC_SCCS and not lint */
  61
  62 char *
  63 was_nonexistent_tmp_name(char *as, size_t aslen, char *ext)
  64 {
  65     register char  *start, *trv;
  66     struct stat     sbuf;
  67     unsigned        pid;
  68     static unsigned n = 0;
  69     int             i;
  70     int             fd, tries = 0;
  71     int             f;
  72     static unsigned long r = 0;
  73
  74     if(r == 0L)
  75       r = (unsigned)getpid() + time((time_t *)0);
  76
  77     for(i = 5; i > 0; i--)
  78       r = 1664525 * r + 1013904223;
  79
  80     pid = ((unsigned)getpid() * 100) + n++;
  81
  82     pid += (r % 50000L);
  83
  84     /* extra X's get set to 0's */
  85     for(trv = as; *trv; ++trv)
  86       ;
  87
  88     /*
  89      * We should probably make the name random instead of having it
  90      * be the pid.
  91      */
  92     while(*--trv == 'X'){
  93         *trv = (pid % 10) + '0';
  94         pid /= 10;
  95     }
  96
  97     /* add the extension, enough room guaranteed by caller */
  98     if(ext && *ext){
  99         strncat(as, ".", aslen-strlen(as)-1);
 100         as[aslen-1] = '\0';
 101         strncat(as, ext, aslen-strlen(as)-1);
 102         as[aslen-1] = '\0';
 103     }
 104
 105     /*
 106      * Check for write permission on target directory; if you have
 107      * six X's and you can't write the directory, this will run for
 108      * a *very* long time.
 109      */
 110     for(start = ++trv; trv > as && *trv != PATH_SEP[0]; --trv)
 111       ;
 112
 113     if(*trv == PATH_SEP[0]){
 114 #ifdef  _WINDOWS
 115         char treplace;
 116
 117         if((trv - as == 2) && isalpha(as[0]) && as[1] == ':')
 118           trv++;
 119         treplace = *trv;
 120         *trv = '\0';
 121         if(our_stat(as==trv ? PATH_SEP : as, &sbuf) || !(sbuf.st_mode & S_IFDIR))
 122           return((char *)NULL);
 123
 124         *trv = treplace;
 125
 126 #else  /* UNIX */
 127
 128         *trv = '\0';
 129
 130         if(our_stat(as==trv ? PATH_SEP : as, &sbuf) || !(sbuf.st_mode & S_IFDIR))
 131           return((char *)NULL);
 132
 133         *trv = PATH_SEP[0];
 134
 135 #endif
 136     }
 137     else if (our_stat(".", &sbuf) == -1)
 138       return((char *)NULL);
 139
 140     for(;;){
 141         /*
 142          * Check with lstat to be sure we don't have
 143          * a symlink. If lstat fails and no such file, then we
 144          * have a winner. Otherwise, lstat shouldn't fail.
 145          * If lstat succeeds, then skip it because it exists.
 146          */
 147 #ifndef _WINDOWS
 148         if(our_lstat(as, &sbuf)){               /* lstat failed */
 149             if(errno == ENOENT){                /* no such file, success */
 150 #endif /* !_WINDOWS */
 151                 /*
 152                  * Create the file so that the
 153                  * evil ones don't have a chance to put something there
 154                  * that they can read or write before we create it
 155                  * ourselves.
 156                  */
 157                 f = O_CREAT|O_EXCL|O_WRONLY|O_BINARY;
 158
 159                 if((fd=our_open(as, f, 0600)) >= 0 && close(fd) == 0)
 160                   return(as);
 161                 else if(++tries > 3)            /* open failed unexpectedly */
 162                   return((char *)NULL);
 163 #ifndef _WINDOWS
 164             }
 165             else                                /* failed for unknown reason */
 166               return((char *)NULL);
 167         }
 168 #endif /* !_WINDOWS */
 169
 170         for(trv = start;;){
 171             if(!*trv)
 172               return((char *)NULL);
 173
 174             /*
 175              * Change the digits from the initial values into
 176              * lower case letters and try again.
 177              */
 178             if(*trv == 'z')
 179               *trv++ = 'a';
 180             else{
 181                 if(isdigit((unsigned char)*trv))
 182                   *trv = 'a';
 183                 else
 184                   ++*trv;
 185
 186                 break;
 187             }
 188         }
 189     }
 190     /*NOTREACHED*/
 191 }
 192
 193
 194 /*
 195  * This routine is derived from BSD4.3 code,
 196  * Copyright (c) 1988 Regents of the University of California.
 197  * All rights reserved.
 198  */
 199 #if defined(LIBC_SCCS) && !defined(lint)
 200 static char sccsid[] = "@(#)tmpnam.c    4.5 (Berkeley) 6/27/88";
 201 #endif /* LIBC_SCCS and not lint */
 202 /*----------------------------------------------------------------------
 203       Return a unique file name in a given directory.  This is not quite
 204       the same as the usual tempnam() function, though it is similar.
 205       We want it to use the TMPDIR/TMP/TEMP environment variable only if dir
 206       is NULL, instead of using it regardless if it is set.
 207       We also want it to be safer than tempnam().
 208       If we return a filename, we are saying that the file did not exist
 209       at the time this function was called (and it wasn't a symlink pointing
 210       to a file that didn't exist, either).
 211       If dir is NULL this is a temp file in a public directory. In that
 212       case we create the file with permission 0600 before returning.
 213
 214   Args: dir      -- The directory to create the name in
 215         prefix   -- Prefix of the name
 216
 217  Result: Malloc'd string equal to new name is returned.  It must be free'd
 218          by the caller.  Returns the string on success and NULL on failure.
 219   ----*/
 220 char *
 221 temp_nam(char *dir, char *prefix)
 222 {
 223     return(temp_nam_ext(dir, prefix, NULL));
 224 }
 225
 226
 227 /*----------------------------------------------------------------------
 228
 229      Like temp_nam but create a unique name with an extension.
 230
 231  Result: Malloc'd string equal to new name is returned.  It must be free'd
 232          by the caller.  Returns the string on success and NULL on failure.
 233   ----*/
 234 char *
 235 temp_nam_ext(char *dir, char *prefix, char *ext)
 236 {
 237     struct stat buf;
 238     size_t      l, ll;
 239     char       *f, *name;
 240
 241     if(ext == NULL)
 242       ext = "";
 243
 244     if(!(name = (char *)malloc(MAXPATH * sizeof(char))))
 245         return((char *)NULL);
 246
 247     if(!dir && (f = getenv("TMPDIR")) && !our_stat(f, &buf) &&
 248                          (buf.st_mode&S_IFMT) == S_IFDIR &&
 249                          !can_access(f, ACCESSIBLE)){
 250         strncpy(name, f, MAXPATH-1);
 251         name[MAXPATH-1] = '\0';
 252         goto done;
 253     }
 254
 255     if(!dir && (f = getenv("TMP")) && !our_stat(f, &buf) &&
 256                          (buf.st_mode&S_IFMT) == S_IFDIR &&
 257                          !can_access(f, ACCESSIBLE)){
 258         strncpy(name, f, MAXPATH-1);
 259         name[MAXPATH-1] = '\0';
 260         goto done;
 261     }
 262
 263     if(!dir && (f = getenv("TEMP")) && !our_stat(f, &buf) &&
 264                          (buf.st_mode&S_IFMT) == S_IFDIR &&
 265                          !can_access(f, ACCESSIBLE)){
 266         strncpy(name, f, MAXPATH-1);
 267         name[MAXPATH-1] = '\0';
 268         goto done;
 269     }
 270
 271     if(dir){
 272         strncpy(name, dir, MAXPATH-1);
 273         name[MAXPATH-1] = '\0';
 274
 275 #ifdef  _WINDOWS
 276         if(!*dir || (isalpha(*dir) && *(dir+1) == ':' && !*(dir+2))){
 277             strncat(name, PATH_SEP, MAXPATH-strlen(name)-1);
 278             name[MAXPATH-1] = '\0';
 279         }
 280 #endif
 281
 282         if(!our_stat(name, &buf)
 283            && (buf.st_mode&S_IFMT) == S_IFDIR
 284            && !can_access(name, ACCESSIBLE)){
 285             strncpy(name, dir, MAXPATH-1);
 286             name[MAXPATH-1] = '\0';
 287             goto done;
 288         }
 289     }
 290
 291 #ifndef P_tmpdir
 292 #ifdef  _WINDOWS
 293 #define P_tmpdir        "\\tmp"
 294 #else  /* UNIX */
 295 #define P_tmpdir        "/usr/tmp"
 296 #endif /* UNIX */
 297 #endif
 298
 299     if(!our_stat(P_tmpdir, &buf) &&
 300                          (buf.st_mode&S_IFMT) == S_IFDIR &&
 301                          !can_access(P_tmpdir, ACCESSIBLE)){
 302         strncpy(name, P_tmpdir, MAXPATH-1);
 303         name[MAXPATH-1] = '\0';
 304         goto done;
 305     }
 306
 307 #ifndef _WINDOWS
 308     if(!our_stat("/tmp", &buf) &&
 309                          (buf.st_mode&S_IFMT) == S_IFDIR &&
 310                          !can_access("/tmp", ACCESSIBLE)){
 311         strncpy(name, "/tmp", MAXPATH-1);
 312         name[MAXPATH-1] = '\0';
 313         goto done;
 314     }
 315 #endif
 316
 317     free((void *)name);
 318     return((char *)NULL);
 319
 320 done:
 321     f = NULL;
 322     if(name[0] && *((f = &name[l=strlen(name)]) - 1) != PATH_SEP[0] && l+1 < MAXPATH){
 323         *f++ = PATH_SEP[0];
 324         *f = '\0';
 325         l++;
 326     }
 327
 328     if(prefix && (ll = strlen(prefix)) && l+ll < MAXPATH){
 329         strncpy(f, prefix, MAXPATH-(f-name));
 330         name[MAXPATH-1] = '\0';
 331         f += ll;
 332         l += ll;
 333     }
 334
 335     if(l+5+(ext[0] ? strlen(ext)+1 : 0) < MAXPATH){
 336         strncpy(f, "XXXXX", MAXPATH-(f-name));
 337         name[MAXPATH-1] = '\0';
 338     }
 339     else{
 340         free((void *)name);
 341         return((char *)NULL);
 342     }
 343
 344     return(was_nonexistent_tmp_name(name, MAXPATH, ext));
 345 }