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
   
   Added 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"

#ifdef WIN32
#include <io.h>
#include <direct.h>
#include <process.h>
#define sleep(s) Sleep(s*1000)
#define S_IWUSR _S_IWRITE
#define S_IRUSR _S_IREAD
#else
#include <unistd.h>
#endif
#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>

#if defined(S_IFDIR) && !defined(S_ISDIR)
#define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif

#ifndef SHORTNAMES

static unsigned long namecounter = 0;

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

  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] = "";
  char normalizedmaildir[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';

  mixfile(normalizedmaildir, maildir);
  if ((checkDirectory(normalizedmaildir, NULL, create) != 0) ||
      (checkDirectory(normalizedmaildir, "tmp", create) != 0) ||
      (checkDirectory(normalizedmaildir, "cur", create) != 0) ||
      (checkDirectory(normalizedmaildir, "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(normalizedmaildir) != 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';
    strcatn(tmpname, "tmp" DIRSEPSTR, MAX_SUBNAME);
    strcatn(tmpname, basename, MAX_SUBNAME);
    strcatn(newname, "new" DIRSEPSTR, MAX_SUBNAME);
    strcatn(newname, basename, MAX_SUBNAME);
        
    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';
    strcatn(newname, "new" DIRSEPSTR, MAX_SUBNAME);
    strcatn(newname, basename, MAX_SUBNAME);
  }
#else /* POSIX */
  /* On non POSIX systems we simply use rename(). Let's hope 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;
}

#else /* no SHORTNAMES */
int maildirWrite(char *maildir, BUFFER *message, int create) {
{
  errlog(ERRORMSG, "Maildir delivery does not work with SHORTNAMES.\n");
  return -1;
}
#endif /* no SHORTNAMES */


#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	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	rabbi	221	Added by drt@un.bewaff.net - http://c0re.jp/
6	weaselp	153
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	weaselp	162	#ifdef WIN32
16			#include <io.h>
17			#include <direct.h>
18			#include <process.h>
19			#define sleep(s) Sleep(s*1000)
20			#define S_IWUSR _S_IWRITE
21			#define S_IRUSR _S_IREAD
22			#else
23	weaselp	153	#include <unistd.h>
24	weaselp	162	#endif
25	weaselp	153	#include <fcntl.h>
26			#include <time.h>
27			#include <string.h>
28			#include <sys/stat.h>
29			#include <sys/types.h>
30			#include <errno.h>
31			#include <stdarg.h>
32	weaselp	156	#include <assert.h>
33	weaselp	153
34	weaselp	162	#if defined(S_IFDIR) && !defined(S_ISDIR)
35			#define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
36			#endif
37
38	weaselp	180	#ifndef SHORTNAMES
39
40	weaselp	153	static unsigned long namecounter = 0;
41
42			int checkDirectory(char dir, char append, int create) {
43			char tmp[PATHMAX];
44			struct stat buf;
45			int err;
46
47			tmp[0] = '\0';
48	weaselp	163	strcatn(tmp, dir, PATHMAX);
49			if (append)
50			strcatn(tmp, append, PATHMAX);
51	weaselp	153
52			err = stat(tmp, &buf);
53			if (err == -1) {
54			if (create) {
55			#ifndef POSIX
56			err = mkdir(tmp);
57			#else
58			err = mkdir(tmp, S_IRWXU);
59			#endif
60			if (err == 0)
61			errlog(NOTICE, "Creating directory %s.\n", tmp);
62			} else
63			err = 1;
64			} else if (!S_ISDIR(buf.st_mode))
65			err = -1;
66
67			return err;
68			}
69
70			/* Write "message" to "maildir", retunr 0 on success, -1 on failure */
71	weaselp	155	#define MAX_BASENAME 113 /* actual length should be smaller than 111 bytes */
72			#define MAX_SUBNAME 123 /* actual length should be smaller than 115 bytes */
73	weaselp	153	int maildirWrite(char maildir, BUFFER message, int create) {
74			int fd;
75			int count;
76			int returnValue;
77			char hostname[64];
78			struct stat statbuf;
79	weaselp	155	char basename[MAX_BASENAME];
80			char tmpname[MAX_SUBNAME];
81			char newname[MAX_SUBNAME];
82			int messagesize;
83	weaselp	156	char olddirectory[PATHMAX] = "";
84	weaselp	163	char normalizedmaildir[PATHMAX];
85	weaselp	153
86			/* Declare a handler for SIGALRM so we can time out. */
87			/* set_handler(SIGALRM, alarm_handler); */
88			/* alarm(86400); */
89
90			hostname[0] = '\0';
91			gethostname(hostname, 63);
92			hostname[63] = '\0';
93
94	weaselp	163	mixfile(normalizedmaildir, maildir);
95			if ((checkDirectory(normalizedmaildir, NULL, create) != 0) \|\|
96			(checkDirectory(normalizedmaildir, "tmp", create) != 0) \|\|
97			(checkDirectory(normalizedmaildir, "cur", create) != 0) \|\|
98			(checkDirectory(normalizedmaildir, "new", create) != 0)) {
99	weaselp	153	returnValue = -1;
100			goto realend;
101			}
102
103	weaselp	155	messagesize = message->length;
104
105	weaselp	156	/* Step 1: chdir to maildir (and save current dir) */
106			if (getcwd(olddirectory, PATHMAX) == NULL) {
107	weaselp	154	returnValue = -1;
108			goto realend;
109			}
110	weaselp	156	olddirectory[PATHMAX-1] = '\0';
111	weaselp	163	if(chdir(normalizedmaildir) != 0) {
112	weaselp	153	returnValue = -1;
113			goto functionExit;
114			}
115
116			/* Step 2: Stat the temporary file. Wait for ENOENT as a response. */
117			for (count = 0;; count++) {
118			tmpname[0] = '\0';
119			newname[0] = '\0';
120	weaselp	155	snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
121			time(NULL), getpid(), namecounter++, hostname, messagesize);
122			basename[MAX_BASENAME-1] = '\0';
123	weaselp	163	strcatn(tmpname, "tmp" DIRSEPSTR, MAX_SUBNAME);
124			strcatn(tmpname, basename, MAX_SUBNAME);
125			strcatn(newname, "new" DIRSEPSTR, MAX_SUBNAME);
126			strcatn(newname, basename, MAX_SUBNAME);
127	weaselp	153
128			if (stat(tmpname, &statbuf) == 0)
129			errno = EEXIST;
130			else if (errno == ENOENT) {
131			/* Step 4: create the file (at least try) */
132			fd = open(tmpname, O_WRONLY\|O_CREAT\|O_EXCL, S_IWUSR\|S_IRUSR);
133			if (fd >= 0)
134			break; /* we managed to open the file */
135			}
136
137			if (count > 5) {
138			/* Too many retries - give up */
139			errlog(ERRORMSG, "Can't create message in %s\n", maildir);
140			returnValue = -1;
141			goto functionExit;
142			}
143
144			/* Step 3: sleep and retry */
145			sleep(2);
146			}
147
148			/* Step 5: write file */
149			if(write(fd, message->data, message->length) != message->length) {
150			returnValue = -1;
151			goto functionExit;
152			}
153
154			/* on NFS this could fail */
155			#ifndef WIN32
156			if((fsync(fd) != 0) \|\| (close(fd) != 0)) {
157			#else
158			if((_commit(fd) != 0) \|\| (close(fd) != 0)) {
159			#endif
160			returnValue = -1;
161			goto functionExit;
162			}
163
164			/* Step 6: move message to 'cur' */
165			#ifdef POSIX
166	weaselp	155	for (count = 0;; count++) {
167			if(link(tmpname, newname) != 0) {
168			if (errno == EXDEV \|\| errno == EPERM) {
169			/* We probably are on coda or some other filesystem that does not allow
170			* hardlinks. rename() the file instead of link() and unlink()
171			* I know, It's evil (PP).
172			*/
173			if (rename(tmpname, newname) != 0) {
174			returnValue = -1;
175			goto functionExit;
176			};
177			break;
178			} else if (errno != EEXIST) {
179			returnValue = -1;
180			goto functionExit;
181			}
182			} else {
183			/* We successfully linked the message in new/. Now let's get
184			* rid of our tmp/ entry
185	weaselp	153	*/
186	weaselp	155	if(unlink(tmpname) != 0) {
187			/* unlinking failed */
188	weaselp	153	returnValue = -1;
189			goto functionExit;
190	weaselp	155	}
191			break;
192	weaselp	153	}
193	weaselp	155
194			if (count > 5) {
195			/* Too many retries - give up */
196			errlog(ERRORMSG, "Can't move message to %s/new/\n", maildir);
197	weaselp	153	returnValue = -1;
198			goto functionExit;
199			}
200	weaselp	155
201			sleep(2);
202			newname[0] = '\0';
203			snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
204			time(NULL), getpid(), namecounter++, hostname, messagesize);
205			basename[MAX_BASENAME-1] = '\0';
206	weaselp	163	strcatn(newname, "new" DIRSEPSTR, MAX_SUBNAME);
207			strcatn(newname, basename, MAX_SUBNAME);
208	weaselp	153	}
209			#else /* POSIX */
210	weaselp	180	/* On non POSIX systems we simply use rename(). Let's hope DJB
211	weaselp	153	* never finds out
212			*/
213			if (rename(tmpname, newname) != 0) {
214			returnValue = -1;
215			goto functionExit;
216			};
217			#endif /* POSIX */
218
219			returnValue = 0;
220
221			functionExit:
222			/* return to original directory */
223	weaselp	156	assert(olddirectory[0] != '\0');
224			if(chdir(olddirectory) != 0)
225	weaselp	153	returnValue = -1;
226
227			realend:
228
229			return returnValue;
230			}
231
232	weaselp	180	#else /* no SHORTNAMES */
233			int maildirWrite(char maildir, BUFFER message, int create) {
234			{
235			errlog(ERRORMSG, "Maildir delivery does not work with SHORTNAMES.\n");
236			return -1;
237			}
238			#endif /* no SHORTNAMES */
239
240
241	weaselp	153	#ifdef UNITTEST
242
243			#ifdef NDEBUG
244			#undef NDEBUG
245			#endif
246
247			#include <dirent.h>
248
249			/* mock-up of errlog for unittest */
250			void errlog(int type, char *fmt,...)
251			{
252			va_list ap;
253
254			va_start(ap, fmt);
255			vfprintf(stderr, fmt, ap);
256			va_end(ap);
257			}
258
259			/* main for unittest */
260			int main()
261			{
262			int i, count = 23;
263			int fd;
264			DIR *d;
265			struct dirent *de;
266			BUFFER message;
267			char text[] = "From: nobody@un.bewaff.net\nTo: hackers@c0re.jp\nSubject: testing\n\nthis is just a test\n";
268			char buf[1024];
269
270			/* create buffer with test data */
271			message.data = text;
272			message.length = strlen(text);
273
274			/* write <count> messages to maildir */
275			for(i = 0; i < count; i++)
276			assert(maildirWrite("Maildir.test_maildir", message, 1) == 0);
277
278			/* read them back */
279			assert((d = opendir("Maildir.test_maildir/new")) != NULL);
280			for (i = 0; i < count + 2; i++)
281			{
282			de = readdir(d);
283			if(de->d_name[0] != '.')
284			{
285			buf[0] = '\0';
286			strcat(buf, "Maildir.test_maildir/new/");
287			strcat(buf, de->d_name);
288			fd = open(buf, O_RDONLY);
289			assert(unlink(buf) == 0);
290			assert(read(fd, buf, strlen(text)) == strlen(text));
291			buf[strlen(text)] = '\0';
292			/* check if they match the original message */
293			assert(strcmp(text, buf) == 0);
294			close(fd);
295			}
296			}
297
298			/* no files left in directory? */
299			assert(readdir(d) == NULL);
300
301			/* delete maildir */
302			assert(rmdir("Maildir.test_maildir/tmp") == 0);
303			assert(rmdir("Maildir.test_maildir/new") == 0);
304			assert(rmdir("Maildir.test_maildir/cur") == 0);
305			assert(rmdir("Maildir.test_maildir") == 0);
306
307			/* check if writing to a non existant maildir yilds an error */
308			assert(maildirWrite("Maildir.test_maildir", &message, 0) == -1);
309
310			puts("OK");
311			}
312			#endif /* UNITTEST */