contrib/notmuch-deliver/maildrop/maildir/maildiropen.c

   1 /*
   2 ** Copyright 2000 Double Precision, Inc.
   3 ** See COPYING for distribution information.
   4 */
   5
   6 #if HAVE_CONFIG_H
   7 #include "config.h"
   8 #endif
   9
  10 #include        <sys/types.h>
  11 #include        <sys/stat.h>
  12 #include        <string.h>
  13 #include        <stdlib.h>
  14 #include        <time.h>
  15 #if     HAVE_UNISTD_H
  16 #include        <unistd.h>
  17 #endif
  18 #include        <stdio.h>
  19 #include        <ctype.h>
  20 #include        <errno.h>
  21 #include        <fcntl.h>
  22
  23 #include        "maildirmisc.h"
  24
  25
  26 char *maildir_getlink(const char *filename)
  27 {
  28 #if     HAVE_READLINK
  29 size_t  bufsiz;
  30 char    *buf;
  31
  32         bufsiz=0;
  33         buf=0;
  34
  35         for (;;)
  36         {
  37         int     n;
  38
  39                 if (buf)        free(buf);
  40                 bufsiz += 256;
  41                 if ((buf=malloc(bufsiz)) == 0)
  42                 {
  43                         perror("malloc");
  44                         return (0);
  45                 }
  46                 if ((n=readlink(filename, buf, bufsiz)) < 0)
  47                 {
  48                         free(buf);
  49                         return (0);
  50                 }
  51                 if (n < bufsiz)
  52                 {
  53                         buf[n]=0;
  54                         break;
  55                 }
  56         }
  57         return (buf);
  58 #else
  59         return (0);
  60 #endif
  61 }
  62
  63 int maildir_semisafeopen(const char *path, int mode, int perm)
  64 {
  65
  66 #if     HAVE_READLINK
  67
  68 char    *l=maildir_getlink(path);
  69
  70         if (l)
  71         {
  72         int     f;
  73
  74                 if (*l != '/')
  75                 {
  76                 char    *q=malloc(strlen(path)+strlen(l)+2);
  77                 char    *s;
  78
  79                         if (!q)
  80                         {
  81                                 free(l);
  82                                 return (-1);
  83                         }
  84
  85                         strcpy(q, path);
  86                         if ((s=strchr(q, '/')) != 0)
  87                                 s[1]=0;
  88                         else    *q=0;
  89                         strcat(q, l);
  90                         free(l);
  91                         l=q;
  92                 }
  93
  94                 f=maildir_safeopen(l, mode, perm);
  95
  96                 free(l);
  97                 return (f);
  98         }
  99 #endif
 100
 101         return (maildir_safeopen(path, mode, perm));
 102 }
 103
 104 int maildir_safeopen(const char *path, int mode, int perm)
 105 {
 106         struct  stat    stat1;
 107
 108         return maildir_safeopen_stat(path, mode, perm, &stat1);
 109 }
 110
 111 int maildir_safeopen_stat(const char *path, int mode, int perm,
 112                           struct stat *stat1)
 113 {
 114         struct  stat    stat2;
 115
 116         int     fd=open(path, mode
 117 #ifdef  O_NONBLOCK
 118                         | O_NONBLOCK
 119 #else
 120                         | O_NDELAY
 121 #endif
 122                         , perm);
 123
 124         if (fd < 0)     return (fd);
 125         if (fcntl(fd, F_SETFL, (mode & O_APPEND)) || fstat(fd, stat1)
 126             || lstat(path, &stat2))
 127         {
 128                 close(fd);
 129                 return (-1);
 130         }
 131
 132         if (stat1->st_dev != stat2.st_dev || stat1->st_ino != stat2.st_ino)
 133         {
 134                 close(fd);
 135                 errno=ENOENT;
 136                 return (-1);
 137         }
 138
 139         return (fd);
 140 }