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mkdtemp.c File Reference
#include "c.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
Include dependency graph for mkdtemp.c:

Go to the source code of this file.

Macros

#define _DIAGASSERT(x)   do {} while (0)
 

Functions

static int GETTEMP (char *path, int *doopen, int domkdir)
 
char * mkdtemp (char *path)
 

Macro Definition Documentation

#define _DIAGASSERT (   x)    do {} while (0)

Definition at line 21 of file mkdtemp.c.

Referenced by GETTEMP(), and mkdtemp().

Function Documentation

static int GETTEMP ( char *  path,
int *  doopen,
int  domkdir 
)
static

Definition at line 94 of file mkdtemp.c.

References _DIAGASSERT, lstat, and mkdir.

Referenced by mkdtemp().

95 {
96  char *start,
97  *trv;
98  struct stat sbuf;
99  u_int pid;
100 
101  /*
102  * To guarantee multiple calls generate unique names even if the file is
103  * not created. 676 different possibilities with 7 or more X's, 26 with 6
104  * or less.
105  */
106  static char xtra[2] = "aa";
107  int xcnt = 0;
108 
109  _DIAGASSERT(path != NULL);
110  /* doopen may be NULL */
111 
112  pid = getpid();
113 
114  /* Move to end of path and count trailing X's. */
115  for (trv = path; *trv; ++trv)
116  if (*trv == 'X')
117  xcnt++;
118  else
119  xcnt = 0;
120 
121  /* Use at least one from xtra. Use 2 if more than 6 X's. */
122  if (xcnt > 0)
123  {
124  *--trv = xtra[0];
125  xcnt--;
126  }
127  if (xcnt > 5)
128  {
129  *--trv = xtra[1];
130  xcnt--;
131  }
132 
133  /* Set remaining X's to pid digits with 0's to the left. */
134  for (; xcnt > 0; xcnt--)
135  {
136  *--trv = (pid % 10) + '0';
137  pid /= 10;
138  }
139 
140  /* update xtra for next call. */
141  if (xtra[0] != 'z')
142  xtra[0]++;
143  else
144  {
145  xtra[0] = 'a';
146  if (xtra[1] != 'z')
147  xtra[1]++;
148  else
149  xtra[1] = 'a';
150  }
151 
152  /*
153  * check the target directory; if you have six X's and it doesn't exist
154  * this runs for a *very* long time.
155  */
156  for (start = trv + 1;; --trv)
157  {
158  if (trv <= path)
159  break;
160  if (*trv == '/')
161  {
162  int e;
163 
164  *trv = '\0';
165  e = stat(path, &sbuf);
166  *trv = '/';
167  if (e == -1)
168  return doopen == NULL && !domkdir;
169  if (!S_ISDIR(sbuf.st_mode))
170  {
171  errno = ENOTDIR;
172  return doopen == NULL && !domkdir;
173  }
174  break;
175  }
176  }
177 
178  for (;;)
179  {
180  if (doopen)
181  {
182  if ((*doopen =
183  open(path, O_CREAT | O_EXCL | O_RDWR, 0600)) >= 0)
184  return 1;
185  if (errno != EEXIST)
186  return 0;
187  }
188  else if (domkdir)
189  {
190  if (mkdir(path, 0700) >= 0)
191  return 1;
192  if (errno != EEXIST)
193  return 0;
194  }
195  else if (lstat(path, &sbuf))
196  return errno == ENOENT ? 1 : 0;
197 
198  /* tricky little algorithm for backward compatibility */
199  for (trv = start;;)
200  {
201  if (!*trv)
202  return 0;
203  if (*trv == 'z')
204  *trv++ = 'a';
205  else
206  {
207  if (isdigit((unsigned char) *trv))
208  *trv = 'a';
209  else
210  ++*trv;
211  break;
212  }
213  }
214  }
215  /* NOTREACHED */
216 }
#define _DIAGASSERT(x)
Definition: mkdtemp.c:21
#define mkdir(a, b)
Definition: win32.h:57
e
Definition: preproc-init.c:82
#define lstat(path, sb)
Definition: win32.h:262
char* mkdtemp ( char *  path)

Definition at line 286 of file mkdtemp.c.

References _DIAGASSERT, and GETTEMP().

287 {
288  _DIAGASSERT(path != NULL);
289 
290  return GETTEMP(path, NULL, 1) ? path : NULL;
291 }
#define _DIAGASSERT(x)
Definition: mkdtemp.c:21
static int GETTEMP(char *path, int *doopen, int domkdir)
Definition: mkdtemp.c:94