Mix/Src/maildir.c

/* Maildir support for Mixmaster 3 - see
   http://www.qmail.org/man/man5/maildir.html and
   http://cr.yp.to/proto/maildir.html
   
   hacked by drt@un.bewaff.net - http://c0re.jp/

   To test it try:
   $ gcc maildir.c -DUNITTEST -o test_maildir
   $ ./test_maildir
   this should print a single line saying "OK"
*/

#include "mix3.h"

#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <stdarg.h>

static unsigned long namecounter = 0;

int checkDirectory(char *dir, char *append, int create) {
  char tmp[PATHMAX];
  struct stat buf;
  int err;
  
  tmp[0] = '\0';
  strncat(tmp, dir, PATHMAX);
  tmp[PATHMAX-1] = '\0';
  if (append) {
    strncat(tmp, append, PATHMAX);
    tmp[PATHMAX-1] = '\0';
  }

  err = stat(tmp, &buf);
  if (err == -1) {
    if (create) {
#ifndef POSIX
      err = mkdir(tmp);
#else
      err = mkdir(tmp, S_IRWXU);
#endif
      if (err == 0)
        errlog(NOTICE, "Creating directory %s.\n", tmp);
    } else
      err = 1;
  } else if (!S_ISDIR(buf.st_mode))
    err = -1;

  return err;
}

/* Write "message" to "maildir", retunr 0 on success, -1 on failure */
#define MAX_BASENAME 113 /* actual length should be smaller than 111 bytes */
#define MAX_SUBNAME 123 /* actual length should be smaller than 115 bytes */
int maildirWrite(char *maildir, BUFFER *message, int create) {
  int fd;
  int currDir;
  int count;
  int returnValue;
  char hostname[64];
  struct stat statbuf;
  char basename[MAX_BASENAME];
  char tmpname[MAX_SUBNAME];
  char newname[MAX_SUBNAME];
  int messagesize;

  /* Declare a handler for SIGALRM so we can time out. */ 
  /* set_handler(SIGALRM, alarm_handler);  */
  /* alarm(86400); */
 
  hostname[0] = '\0';
  gethostname(hostname, 63);
  hostname[63] = '\0';

  if ((checkDirectory(maildir, NULL, create) != 0) ||
      (checkDirectory(maildir, "tmp", create) != 0) ||
      (checkDirectory(maildir, "cur", create) != 0) ||
      (checkDirectory(maildir, "new", create) != 0)) {
    returnValue = -1;
    goto realend;
  }

  messagesize = message->length;

  /* Step 1: chdir to maildir (and save actual dir by opening it) */
  if((currDir = open(".", O_RDONLY)) < 0) {
    returnValue = -1;
    goto realend;
  }
  if(chdir(maildir) != 0) {
    returnValue = -1;
    goto functionExit;
  }
  
  /* Step 2:  Stat the temporary file.  Wait for ENOENT as a response. */ 
  for (count = 0;; count++) {
    tmpname[0] = '\0';
    newname[0] = '\0';
    snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
      time(NULL), getpid(), namecounter++, hostname, messagesize);
    basename[MAX_BASENAME-1] = '\0';
    strncat(tmpname, "tmp/", MAX_SUBNAME);
    strncat(tmpname, basename, MAX_SUBNAME);
    tmpname[MAX_SUBNAME-1] = '\0';
    strncat(newname, "new/", MAX_SUBNAME);
    strncat(newname, basename, MAX_SUBNAME);
    newname[MAX_SUBNAME-1] = '\0';
        
    if (stat(tmpname, &statbuf) == 0)
      errno = EEXIST;
    else if (errno == ENOENT) {
      /* Step 4: create the file (at least try) */
      fd = open(tmpname, O_WRONLY|O_CREAT|O_EXCL, S_IWUSR|S_IRUSR); 
      if (fd >= 0) 
        break; /* we managed to open the file */
    }

    if (count > 5) {
      /* Too many retries - give up */    
      errlog(ERRORMSG, "Can't create message in %s\n", maildir);
      returnValue = -1;
      goto functionExit;
    }

    /* Step 3: sleep and retry */
    sleep(2);
  }
 
  /* Step 5:  write file */ 
  if(write(fd, message->data, message->length) != message->length) {
    returnValue = -1;
    goto functionExit;
  }

  /* on NFS this could fail */
#ifndef WIN32
  if((fsync(fd) != 0) || (close(fd) != 0)) {
#else
  if((_commit(fd) != 0) || (close(fd) != 0)) {
#endif
    returnValue = -1;
    goto functionExit;
  } 

  /* Step 6: move message to 'cur' */
#ifdef POSIX
  for (count = 0;; count++) {
    if(link(tmpname, newname) != 0) {
      if (errno == EXDEV || errno == EPERM) {
        /* We probably are on coda or some other filesystem that does not allow
         * hardlinks. rename() the file instead of link() and unlink()
         * I know, It's evil (PP).
         */
        if (rename(tmpname, newname) != 0) {
          returnValue = -1;
          goto functionExit;
        };
        break;
      } else if (errno != EEXIST) {
        returnValue = -1;
        goto functionExit;
      }
    } else {
      /* We successfully linked the message in new/. Now let's get
       * rid of our tmp/ entry
       */
      if(unlink(tmpname) != 0) {
        /* unlinking failed */
        returnValue = -1;
        goto functionExit;
      }
      break;
    }

    if (count > 5) {
      /* Too many retries - give up */    
      errlog(ERRORMSG, "Can't move message to %s/new/\n", maildir);
      returnValue = -1;
      goto functionExit;
    }

    sleep(2);
    newname[0] = '\0';
    snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
      time(NULL), getpid(), namecounter++, hostname, messagesize);
    basename[MAX_BASENAME-1] = '\0';
    strncat(newname, "new/", MAX_SUBNAME);
    strncat(newname, basename, MAX_SUBNAME);
    newname[MAX_SUBNAME-1] = '\0';
  }
#else /* POSIX */
  /* On non POSIX systems we simply use rename(). Let's hobe DJB
   * never finds out
   */
  if (rename(tmpname, newname) != 0) {
    returnValue = -1;
    goto functionExit;
  };
#endif /* POSIX */

  returnValue = 0;

functionExit:
  /* return to original directory */
  if ((fchdir(currDir) != 0) || (close(currDir) != 0))
    returnValue = -1;
  
realend:
  
  return returnValue;
}

#ifdef UNITTEST

#ifdef NDEBUG
#undef NDEBUG
#endif

#include <dirent.h>
#include <assert.h>

/* mock-up of errlog for unittest */
void errlog(int type, char *fmt,...)
{
  va_list ap;
  
  va_start(ap, fmt);
  vfprintf(stderr, fmt, ap);
  va_end(ap);
}

/* main for unittest */
int main()
{
  int i, count = 23;
  int fd;
  DIR *d;
  struct dirent *de;
  BUFFER message;
  char text[] = "From: nobody@un.bewaff.net\nTo: hackers@c0re.jp\nSubject: testing\n\nthis is just a test\n";
  char buf[1024];

  /* create buffer with test data */
  message.data = text;
  message.length = strlen(text);

  /* write <count> messages to maildir */
  for(i = 0; i < count; i++)
    assert(maildirWrite("Maildir.test_maildir", message, 1) == 0);

  /* read them back */
  assert((d = opendir("Maildir.test_maildir/new")) != NULL);
  for (i = 0; i < count + 2; i++) 
    {
      de = readdir(d);
      if(de->d_name[0] != '.')
        {
          buf[0] = '\0';
          strcat(buf, "Maildir.test_maildir/new/");
          strcat(buf, de->d_name);
          fd = open(buf, O_RDONLY);
          assert(unlink(buf) == 0);
          assert(read(fd, buf, strlen(text)) == strlen(text));
          buf[strlen(text)] = '\0';
          /* check if they match the original message */
          assert(strcmp(text, buf) == 0);
          close(fd);
        }
    }
  
  /* no files left in directory? */
  assert(readdir(d) == NULL);

  /* delete maildir */
  assert(rmdir("Maildir.test_maildir/tmp") == 0);
  assert(rmdir("Maildir.test_maildir/new") == 0);
  assert(rmdir("Maildir.test_maildir/cur") == 0);
  assert(rmdir("Maildir.test_maildir") == 0);

  /* check if writing to a non existant maildir yilds an error */
  assert(maildirWrite("Maildir.test_maildir", &message, 0) == -1);
  
  puts("OK");
}
#endif /* UNITTEST */
1	weaselp	153	/* Maildir support for Mixmaster 3 - see
2			http://www.qmail.org/man/man5/maildir.html and
3			http://cr.yp.to/proto/maildir.html
4
5			hacked by drt@un.bewaff.net - http://c0re.jp/
6
7			To test it try:
8			$ gcc maildir.c -DUNITTEST -o test_maildir
9			$ ./test_maildir
10			this should print a single line saying "OK"
11			*/
12
13			#include "mix3.h"
14
15			#include <unistd.h>
16			#include <fcntl.h>
17			#include <time.h>
18			#include <string.h>
19			#include <sys/stat.h>
20			#include <sys/types.h>
21			#include <errno.h>
22			#include <stdarg.h>
23
24			static unsigned long namecounter = 0;
25
26			int checkDirectory(char dir, char append, int create) {
27			char tmp[PATHMAX];
28			struct stat buf;
29			int err;
30
31			tmp[0] = '\0';
32			strncat(tmp, dir, PATHMAX);
33			tmp[PATHMAX-1] = '\0';
34			if (append) {
35			strncat(tmp, append, PATHMAX);
36			tmp[PATHMAX-1] = '\0';
37			}
38
39			err = stat(tmp, &buf);
40			if (err == -1) {
41			if (create) {
42			#ifndef POSIX
43			err = mkdir(tmp);
44			#else
45			err = mkdir(tmp, S_IRWXU);
46			#endif
47			if (err == 0)
48			errlog(NOTICE, "Creating directory %s.\n", tmp);
49			} else
50			err = 1;
51			} else if (!S_ISDIR(buf.st_mode))
52			err = -1;
53
54			return err;
55			}
56
57			/* Write "message" to "maildir", retunr 0 on success, -1 on failure */
58	weaselp	155	#define MAX_BASENAME 113 /* actual length should be smaller than 111 bytes */
59			#define MAX_SUBNAME 123 /* actual length should be smaller than 115 bytes */
60	weaselp	153	int maildirWrite(char maildir, BUFFER message, int create) {
61			int fd;
62			int currDir;
63			int count;
64			int returnValue;
65			char hostname[64];
66			struct stat statbuf;
67	weaselp	155	char basename[MAX_BASENAME];
68			char tmpname[MAX_SUBNAME];
69			char newname[MAX_SUBNAME];
70			int messagesize;
71	weaselp	153
72			/* Declare a handler for SIGALRM so we can time out. */
73			/* set_handler(SIGALRM, alarm_handler); */
74			/* alarm(86400); */
75
76			hostname[0] = '\0';
77			gethostname(hostname, 63);
78			hostname[63] = '\0';
79
80			if ((checkDirectory(maildir, NULL, create) != 0) \|\|
81			(checkDirectory(maildir, "tmp", create) != 0) \|\|
82			(checkDirectory(maildir, "cur", create) != 0) \|\|
83			(checkDirectory(maildir, "new", create) != 0)) {
84			returnValue = -1;
85			goto realend;
86			}
87
88	weaselp	155	messagesize = message->length;
89
90	weaselp	153	/* Step 1: chdir to maildir (and save actual dir by opening it) */
91	weaselp	154	if((currDir = open(".", O_RDONLY)) < 0) {
92			returnValue = -1;
93			goto realend;
94			}
95	weaselp	153	if(chdir(maildir) != 0) {
96			returnValue = -1;
97			goto functionExit;
98			}
99
100			/* Step 2: Stat the temporary file. Wait for ENOENT as a response. */
101			for (count = 0;; count++) {
102			tmpname[0] = '\0';
103			newname[0] = '\0';
104	weaselp	155	snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
105			time(NULL), getpid(), namecounter++, hostname, messagesize);
106			basename[MAX_BASENAME-1] = '\0';
107			strncat(tmpname, "tmp/", MAX_SUBNAME);
108			strncat(tmpname, basename, MAX_SUBNAME);
109			tmpname[MAX_SUBNAME-1] = '\0';
110			strncat(newname, "new/", MAX_SUBNAME);
111			strncat(newname, basename, MAX_SUBNAME);
112			newname[MAX_SUBNAME-1] = '\0';
113	weaselp	153
114			if (stat(tmpname, &statbuf) == 0)
115			errno = EEXIST;
116			else if (errno == ENOENT) {
117			/* Step 4: create the file (at least try) */
118			fd = open(tmpname, O_WRONLY\|O_CREAT\|O_EXCL, S_IWUSR\|S_IRUSR);
119			if (fd >= 0)
120			break; /* we managed to open the file */
121			}
122
123			if (count > 5) {
124			/* Too many retries - give up */
125			errlog(ERRORMSG, "Can't create message in %s\n", maildir);
126			returnValue = -1;
127			goto functionExit;
128			}
129
130			/* Step 3: sleep and retry */
131			sleep(2);
132			}
133
134			/* Step 5: write file */
135			if(write(fd, message->data, message->length) != message->length) {
136			returnValue = -1;
137			goto functionExit;
138			}
139
140			/* on NFS this could fail */
141			#ifndef WIN32
142			if((fsync(fd) != 0) \|\| (close(fd) != 0)) {
143			#else
144			if((_commit(fd) != 0) \|\| (close(fd) != 0)) {
145			#endif
146			returnValue = -1;
147			goto functionExit;
148			}
149
150			/* Step 6: move message to 'cur' */
151			#ifdef POSIX
152	weaselp	155	for (count = 0;; count++) {
153			if(link(tmpname, newname) != 0) {
154			if (errno == EXDEV \|\| errno == EPERM) {
155			/* We probably are on coda or some other filesystem that does not allow
156			* hardlinks. rename() the file instead of link() and unlink()
157			* I know, It's evil (PP).
158			*/
159			if (rename(tmpname, newname) != 0) {
160			returnValue = -1;
161			goto functionExit;
162			};
163			break;
164			} else if (errno != EEXIST) {
165			returnValue = -1;
166			goto functionExit;
167			}
168			} else {
169			/* We successfully linked the message in new/. Now let's get
170			* rid of our tmp/ entry
171	weaselp	153	*/
172	weaselp	155	if(unlink(tmpname) != 0) {
173			/* unlinking failed */
174	weaselp	153	returnValue = -1;
175			goto functionExit;
176	weaselp	155	}
177			break;
178	weaselp	153	}
179	weaselp	155
180			if (count > 5) {
181			/* Too many retries - give up */
182			errlog(ERRORMSG, "Can't move message to %s/new/\n", maildir);
183	weaselp	153	returnValue = -1;
184			goto functionExit;
185			}
186	weaselp	155
187			sleep(2);
188			newname[0] = '\0';
189			snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
190			time(NULL), getpid(), namecounter++, hostname, messagesize);
191			basename[MAX_BASENAME-1] = '\0';
192			strncat(newname, "new/", MAX_SUBNAME);
193			strncat(newname, basename, MAX_SUBNAME);
194			newname[MAX_SUBNAME-1] = '\0';
195	weaselp	153	}
196			#else /* POSIX */
197			/* On non POSIX systems we simply use rename(). Let's hobe DJB
198			* never finds out
199			*/
200			if (rename(tmpname, newname) != 0) {
201			returnValue = -1;
202			goto functionExit;
203			};
204			#endif /* POSIX */
205
206			returnValue = 0;
207
208			functionExit:
209			/* return to original directory */
210			if ((fchdir(currDir) != 0) \|\| (close(currDir) != 0))
211			returnValue = -1;
212
213			realend:
214
215			return returnValue;
216			}
217
218			#ifdef UNITTEST
219
220			#ifdef NDEBUG
221			#undef NDEBUG
222			#endif
223
224			#include <dirent.h>
225			#include <assert.h>
226
227			/* mock-up of errlog for unittest */
228			void errlog(int type, char *fmt,...)
229			{
230			va_list ap;
231
232			va_start(ap, fmt);
233			vfprintf(stderr, fmt, ap);
234			va_end(ap);
235			}
236
237			/* main for unittest */
238			int main()
239			{
240			int i, count = 23;
241			int fd;
242			DIR *d;
243			struct dirent *de;
244			BUFFER message;
245			char text[] = "From: nobody@un.bewaff.net\nTo: hackers@c0re.jp\nSubject: testing\n\nthis is just a test\n";
246			char buf[1024];
247
248			/* create buffer with test data */
249			message.data = text;
250			message.length = strlen(text);
251
252			/* write <count> messages to maildir */
253			for(i = 0; i < count; i++)
254			assert(maildirWrite("Maildir.test_maildir", message, 1) == 0);
255
256			/* read them back */
257			assert((d = opendir("Maildir.test_maildir/new")) != NULL);
258			for (i = 0; i < count + 2; i++)
259			{
260			de = readdir(d);
261			if(de->d_name[0] != '.')
262			{
263			buf[0] = '\0';
264			strcat(buf, "Maildir.test_maildir/new/");
265			strcat(buf, de->d_name);
266			fd = open(buf, O_RDONLY);
267			assert(unlink(buf) == 0);
268			assert(read(fd, buf, strlen(text)) == strlen(text));
269			buf[strlen(text)] = '\0';
270			/* check if they match the original message */
271			assert(strcmp(text, buf) == 0);
272			close(fd);
273			}
274			}
275
276			/* no files left in directory? */
277			assert(readdir(d) == NULL);
278
279			/* delete maildir */
280			assert(rmdir("Maildir.test_maildir/tmp") == 0);
281			assert(rmdir("Maildir.test_maildir/new") == 0);
282			assert(rmdir("Maildir.test_maildir/cur") == 0);
283			assert(rmdir("Maildir.test_maildir") == 0);
284
285			/* check if writing to a non existant maildir yilds an error */
286			assert(maildirWrite("Maildir.test_maildir", &message, 0) == -1);
287
288			puts("OK");
289			}
290			#endif /* UNITTEST */