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>
#include <assert.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 count;
  int returnValue;
  char hostname[64];
  struct stat statbuf;
  char basename[MAX_BASENAME];
  char tmpname[MAX_SUBNAME];
  char newname[MAX_SUBNAME];
  int messagesize;
  char olddirectory[PATHMAX] = "";

  /* 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 current dir) */
  if (getcwd(olddirectory, PATHMAX) == NULL) {
    returnValue = -1;
    goto realend;
  }
  olddirectory[PATHMAX-1] = '\0';
  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);
    tmpname[MAX_SUBNAME-1] = '\0';
    strncat(tmpname, basename, MAX_SUBNAME);
    tmpname[MAX_SUBNAME-1] = '\0';
    strncat(newname, "new/", MAX_SUBNAME);
    newname[MAX_SUBNAME-1] = '\0';
    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);
    newname[MAX_SUBNAME-1] = '\0';
    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 */
  assert(olddirectory[0] != '\0');
  if(chdir(olddirectory) != 0)
    returnValue = -1;
  
realend:
  
  return returnValue;
}

#ifdef UNITTEST

#ifdef NDEBUG
#undef NDEBUG
#endif

#include <dirent.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	/* 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	#include <assert.h>
24
25	static unsigned long namecounter = 0;
26
27	int checkDirectory(char dir, char append, int create) {
28	char tmp[PATHMAX];
29	struct stat buf;
30	int err;
31
32	tmp[0] = '\0';
33	strncat(tmp, dir, PATHMAX);
34	tmp[PATHMAX-1] = '\0';
35	if (append) {
36	strncat(tmp, append, PATHMAX);
37	tmp[PATHMAX-1] = '\0';
38	}
39
40	err = stat(tmp, &buf);
41	if (err == -1) {
42	if (create) {
43	#ifndef POSIX
44	err = mkdir(tmp);
45	#else
46	err = mkdir(tmp, S_IRWXU);
47	#endif
48	if (err == 0)
49	errlog(NOTICE, "Creating directory %s.\n", tmp);
50	} else
51	err = 1;
52	} else if (!S_ISDIR(buf.st_mode))
53	err = -1;
54
55	return err;
56	}
57
58	/* Write "message" to "maildir", retunr 0 on success, -1 on failure */
59	#define MAX_BASENAME 113 /* actual length should be smaller than 111 bytes */
60	#define MAX_SUBNAME 123 /* actual length should be smaller than 115 bytes */
61	int maildirWrite(char maildir, BUFFER message, int create) {
62	int fd;
63	int count;
64	int returnValue;
65	char hostname[64];
66	struct stat statbuf;
67	char basename[MAX_BASENAME];
68	char tmpname[MAX_SUBNAME];
69	char newname[MAX_SUBNAME];
70	int messagesize;
71	char olddirectory[PATHMAX] = "";
72
73	/* Declare a handler for SIGALRM so we can time out. */
74	/* set_handler(SIGALRM, alarm_handler); */
75	/* alarm(86400); */
76
77	hostname[0] = '\0';
78	gethostname(hostname, 63);
79	hostname[63] = '\0';
80
81	if ((checkDirectory(maildir, NULL, create) != 0) \|\|
82	(checkDirectory(maildir, "tmp", create) != 0) \|\|
83	(checkDirectory(maildir, "cur", create) != 0) \|\|
84	(checkDirectory(maildir, "new", create) != 0)) {
85	returnValue = -1;
86	goto realend;
87	}
88
89	messagesize = message->length;
90
91	/* Step 1: chdir to maildir (and save current dir) */
92	if (getcwd(olddirectory, PATHMAX) == NULL) {
93	returnValue = -1;
94	goto realend;
95	}
96	olddirectory[PATHMAX-1] = '\0';
97	if(chdir(maildir) != 0) {
98	returnValue = -1;
99	goto functionExit;
100	}
101
102	/* Step 2: Stat the temporary file. Wait for ENOENT as a response. */
103	for (count = 0;; count++) {
104	tmpname[0] = '\0';
105	newname[0] = '\0';
106	snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
107	time(NULL), getpid(), namecounter++, hostname, messagesize);
108	basename[MAX_BASENAME-1] = '\0';
109	strncat(tmpname, "tmp/", MAX_SUBNAME);
110	tmpname[MAX_SUBNAME-1] = '\0';
111	strncat(tmpname, basename, MAX_SUBNAME);
112	tmpname[MAX_SUBNAME-1] = '\0';
113	strncat(newname, "new/", MAX_SUBNAME);
114	newname[MAX_SUBNAME-1] = '\0';
115	strncat(newname, basename, MAX_SUBNAME);
116	newname[MAX_SUBNAME-1] = '\0';
117
118	if (stat(tmpname, &statbuf) == 0)
119	errno = EEXIST;
120	else if (errno == ENOENT) {
121	/* Step 4: create the file (at least try) */
122	fd = open(tmpname, O_WRONLY\|O_CREAT\|O_EXCL, S_IWUSR\|S_IRUSR);
123	if (fd >= 0)
124	break; /* we managed to open the file */
125	}
126
127	if (count > 5) {
128	/* Too many retries - give up */
129	errlog(ERRORMSG, "Can't create message in %s\n", maildir);
130	returnValue = -1;
131	goto functionExit;
132	}
133
134	/* Step 3: sleep and retry */
135	sleep(2);
136	}
137
138	/* Step 5: write file */
139	if(write(fd, message->data, message->length) != message->length) {
140	returnValue = -1;
141	goto functionExit;
142	}
143
144	/* on NFS this could fail */
145	#ifndef WIN32
146	if((fsync(fd) != 0) \|\| (close(fd) != 0)) {
147	#else
148	if((_commit(fd) != 0) \|\| (close(fd) != 0)) {
149	#endif
150	returnValue = -1;
151	goto functionExit;
152	}
153
154	/* Step 6: move message to 'cur' */
155	#ifdef POSIX
156	for (count = 0;; count++) {
157	if(link(tmpname, newname) != 0) {
158	if (errno == EXDEV \|\| errno == EPERM) {
159	/* We probably are on coda or some other filesystem that does not allow
160	* hardlinks. rename() the file instead of link() and unlink()
161	* I know, It's evil (PP).
162	*/
163	if (rename(tmpname, newname) != 0) {
164	returnValue = -1;
165	goto functionExit;
166	};
167	break;
168	} else if (errno != EEXIST) {
169	returnValue = -1;
170	goto functionExit;
171	}
172	} else {
173	/* We successfully linked the message in new/. Now let's get
174	* rid of our tmp/ entry
175	*/
176	if(unlink(tmpname) != 0) {
177	/* unlinking failed */
178	returnValue = -1;
179	goto functionExit;
180	}
181	break;
182	}
183
184	if (count > 5) {
185	/* Too many retries - give up */
186	errlog(ERRORMSG, "Can't move message to %s/new/\n", maildir);
187	returnValue = -1;
188	goto functionExit;
189	}
190
191	sleep(2);
192	newname[0] = '\0';
193	snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
194	time(NULL), getpid(), namecounter++, hostname, messagesize);
195	basename[MAX_BASENAME-1] = '\0';
196	strncat(newname, "new/", MAX_SUBNAME);
197	newname[MAX_SUBNAME-1] = '\0';
198	strncat(newname, basename, MAX_SUBNAME);
199	newname[MAX_SUBNAME-1] = '\0';
200	}
201	#else /* POSIX */
202	/* On non POSIX systems we simply use rename(). Let's hobe DJB
203	* never finds out
204	*/
205	if (rename(tmpname, newname) != 0) {
206	returnValue = -1;
207	goto functionExit;
208	};
209	#endif /* POSIX */
210
211	returnValue = 0;
212
213	functionExit:
214	/* return to original directory */
215	assert(olddirectory[0] != '\0');
216	if(chdir(olddirectory) != 0)
217	returnValue = -1;
218
219	realend:
220
221	return returnValue;
222	}
223
224	#ifdef UNITTEST
225
226	#ifdef NDEBUG
227	#undef NDEBUG
228	#endif
229
230	#include <dirent.h>
231
232	/* mock-up of errlog for unittest */
233	void errlog(int type, char *fmt,...)
234	{
235	va_list ap;
236
237	va_start(ap, fmt);
238	vfprintf(stderr, fmt, ap);
239	va_end(ap);
240	}
241
242	/* main for unittest */
243	int main()
244	{
245	int i, count = 23;
246	int fd;
247	DIR *d;
248	struct dirent *de;
249	BUFFER message;
250	char text[] = "From: nobody@un.bewaff.net\nTo: hackers@c0re.jp\nSubject: testing\n\nthis is just a test\n";
251	char buf[1024];
252
253	/* create buffer with test data */
254	message.data = text;
255	message.length = strlen(text);
256
257	/* write <count> messages to maildir */
258	for(i = 0; i < count; i++)
259	assert(maildirWrite("Maildir.test_maildir", message, 1) == 0);
260
261	/* read them back */
262	assert((d = opendir("Maildir.test_maildir/new")) != NULL);
263	for (i = 0; i < count + 2; i++)
264	{
265	de = readdir(d);
266	if(de->d_name[0] != '.')
267	{
268	buf[0] = '\0';
269	strcat(buf, "Maildir.test_maildir/new/");
270	strcat(buf, de->d_name);
271	fd = open(buf, O_RDONLY);
272	assert(unlink(buf) == 0);
273	assert(read(fd, buf, strlen(text)) == strlen(text));
274	buf[strlen(text)] = '\0';
275	/* check if they match the original message */
276	assert(strcmp(text, buf) == 0);
277	close(fd);
278	}
279	}
280
281	/* no files left in directory? */
282	assert(readdir(d) == NULL);
283
284	/* delete maildir */
285	assert(rmdir("Maildir.test_maildir/tmp") == 0);
286	assert(rmdir("Maildir.test_maildir/new") == 0);
287	assert(rmdir("Maildir.test_maildir/cur") == 0);
288	assert(rmdir("Maildir.test_maildir") == 0);
289
290	/* check if writing to a non existant maildir yilds an error */
291	assert(maildirWrite("Maildir.test_maildir", &message, 0) == -1);
292
293	puts("OK");
294	}
295	#endif /* UNITTEST */