Removed unnecessary locking. Simplified. Tidied.

This commit is contained in:
Stephen McKay 1996-11-27 12:58:44 +00:00
parent d8c4fd0c82
commit 37b2250f56
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=19983

View File

@ -1,8 +1,9 @@
/*
* Send a compressed CTM delta to a recipient mailing list by encoding it
* in safe ASCII characters, in mailer-friendly chunks, and passing it
* to sendmail. The encoding is almost the same as MIME BASE64, and is
* protected by a simple checksum.
* in safe ASCII characters, in mailer-friendly chunks, and passing them
* to sendmail. Optionally, the chunks can be queued to be sent later by
* ctm_dequeue in controlled bursts. The encoding is almost the same as
* MIME BASE64, and is protected by a simple checksum.
*
* Author: Stephen McKay
*
@ -10,7 +11,7 @@
* In return you should think about all the nice people who give away software.
* Maybe you should write some free software too.
*
* $Id: ctm_smail.c,v 1.7 1996/09/07 18:48:44 peter Exp $
* $Id: ctm_smail.c,v 1.8 1996/09/07 21:06:19 peter Exp $
*/
#include <stdio.h>
@ -22,38 +23,42 @@
#include <sys/stat.h>
#include <errno.h>
#include <paths.h>
#include <limits.h>
#include "error.h"
#include "options.h"
#define DEF_MAX_MSG 64000 /* Default maximum mail msg minus headers. */
#define LINE_LENGTH 76 /* Chars per encode line. Divisible by 4. */
#define LINE_LENGTH 76 /* Chars per encoded line. Divisible by 4. */
void chop_and_send(char *delta, off_t ctm_size, long max_msg_size,
int chop_and_send_or_queue(FILE *dfp, char *delta, off_t ctm_size,
long max_msg_size, char *mail_alias, char *queue_dir);
int chop_and_send(FILE *dfp, char *delta, long msg_size, int npieces,
char *mail_alias);
void chop_and_queue(char *delta, off_t ctm_size, long max_msg_size,
char *queue_dir, char *mail_alias);
unsigned encode_body(FILE *sm_fp, FILE *delta_fp, long msg_size);
int chop_and_queue(FILE *dfp, char *delta, long msg_size, int npieces,
char *mail_alias, char *queue_dir);
void clean_up_queue(char *queue_dir);
int encode_body(FILE *sm_fp, FILE *delta_fp, long msg_size, unsigned *sum);
void write_header(FILE *sfp, char *mail_alias, char *delta, int pce,
int npieces);
void write_trailer(FILE *sfp, unsigned sum);
void apologise(char *delta, off_t ctm_size, long max_ctm_size,
int apologise(char *delta, off_t ctm_size, long max_ctm_size,
char *mail_alias);
FILE *open_sendmail(void);
int close_sendmail(FILE *fp);
int lock_queuedir(char *queue_dir);
void free_lock(int lockf, char *queue_dir);
void add_to_queue(char *queue_dir, char *mail_alias, char *delta, int npieces, char **tempnames);
int
main(int argc, char **argv)
{
int status = 0;
char *delta_file;
char *mail_alias;
long max_msg_size = DEF_MAX_MSG;
long max_ctm_size = 0;
char *log_file = NULL;
char *queue_dir = NULL;
char *delta;
FILE *dfp;
struct stat sb;
err_prog_name(argv[0]);
@ -74,195 +79,213 @@ main(int argc, char **argv)
delta_file = argv[1];
mail_alias = argv[2];
if (stat(delta_file, &sb) < 0)
if ((delta = strrchr(delta_file, '/')) == NULL)
delta = delta_file;
else
delta++;
if ((dfp = fopen(delta_file, "r")) == NULL || fstat(fileno(dfp), &sb) < 0)
{
err("%s: %s", delta_file, strerror(errno));
err("*%s", delta_file);
exit(1);
}
if (max_ctm_size != 0 && sb.st_size > max_ctm_size)
apologise(delta_file, sb.st_size, max_ctm_size, mail_alias);
else if (queue_dir == NULL)
chop_and_send(delta_file, sb.st_size, max_msg_size, mail_alias);
status = apologise(delta, sb.st_size, max_ctm_size, mail_alias);
else
chop_and_queue(delta_file, sb.st_size, max_msg_size, queue_dir, mail_alias);
status = chop_and_send_or_queue(dfp, delta, sb.st_size, max_msg_size,
mail_alias, queue_dir);
fclose(dfp);
return status;
}
/*
* Carve our CTM delta into pieces, encode them, and send or queue them.
* Returns 0 on success, and 1 on failure.
*/
int
chop_and_send_or_queue(FILE *dfp, char *delta, off_t ctm_size,
long max_msg_size, char *mail_alias, char *queue_dir)
{
int npieces;
long msg_size;
long exp_size;
int status;
#undef howmany
#define howmany(x,y) (((x)+((y)-1)) / (y))
/*
* Work out how many pieces we need, bearing in mind that each piece
* grows by 4/3 when encoded. We count the newlines too, but ignore
* all mail headers and piece headers. They are a "small" (almost
* constant) per message overhead that we make the user worry about. :-)
*/
exp_size = ctm_size * 4 / 3;
exp_size += howmany(exp_size, LINE_LENGTH);
npieces = howmany(exp_size, max_msg_size);
msg_size = howmany(ctm_size, npieces);
#undef howmany
if (queue_dir == NULL)
status = chop_and_send(dfp, delta, msg_size, npieces, mail_alias);
else
{
status = chop_and_queue(dfp, delta, msg_size, npieces, mail_alias,
queue_dir);
if (status)
clean_up_queue(queue_dir);
}
return status;
}
/*
* Carve our CTM delta into pieces, encode them, and send them.
* Returns 0 on success, and 1 on failure.
*/
int
chop_and_send(FILE *dfp, char *delta, long msg_size, int npieces,
char *mail_alias)
{
int pce;
FILE *sfp;
unsigned sum;
/*
* Send each chunk directly to sendmail as it is generated.
* No temporary files necessary. If things turn ugly, we just
* have to live with the fact the we have sent only part of
* the delta.
*/
for (pce = 1; pce <= npieces; pce++)
{
int read_error;
if ((sfp = open_sendmail()) == NULL)
return 1;
write_header(sfp, mail_alias, delta, pce, npieces);
read_error = encode_body(sfp, dfp, msg_size, &sum);
if (!read_error)
write_trailer(sfp, sum);
if (!close_sendmail(sfp) || read_error)
return 1;
err("%s %d/%d sent to %s", delta, pce, npieces, mail_alias);
}
return 0;
}
/*
* Carve our CTM delta into pieces, encode them, and send them.
* Construct the tmp queue file name of a delta piece.
*/
void
chop_and_send(char *delta, off_t ctm_size, long max_msg_size, char *mail_alias)
#define mk_tmp_name(fn,qd,p) \
sprintf((fn), "%s/.%08ld.%03d", (qd), (long)getpid(), (p))
/*
* Construct the final queue file name of a delta piece.
*/
#define mk_queue_name(fn,qd,d,p,n) \
sprintf((fn), "%s/%s+%03d-%03d", (qd), (d), (p), (n))
/*
* Carve our CTM delta into pieces, encode them, and queue them.
* Returns 0 on success, and 1 on failure.
*/
int
chop_and_queue(FILE *dfp, char *delta, long msg_size, int npieces,
char *mail_alias, char *queue_dir)
{
int npieces;
long msg_size;
long exp_size;
int pce;
FILE *sfp;
FILE *dfp;
FILE *qfp;
unsigned sum;
char *deltaname;
#ifdef howmany
#undef howmany
#endif
#define howmany(x, y) (((x) + ((y) - 1)) / (y))
char tname[PATH_MAX];
char qname[PATH_MAX];
/*
* Work out how many pieces we need, bearing in mind that each piece
* grows by 4/3 when encoded. We count the newlines too, but ignore
* all mail headers and piece headers. They are a "small" (almost
* constant) per message overhead that we make the user worry about. :-)
* Store each piece in the queue directory, but under temporary names,
* so that they can be deleted without unpleasant consequences if
* anything goes wrong. We could easily fill up a disk, for example.
*/
exp_size = ctm_size * 4 / 3;
exp_size += howmany(exp_size, LINE_LENGTH);
npieces = howmany(exp_size, max_msg_size);
msg_size = howmany(ctm_size, npieces);
#undef howmany
if ((dfp = fopen(delta, "r")) == NULL)
{
err("cannot open '%s' for reading.", delta);
exit(1);
}
deltaname = strrchr(delta, '/');
if (deltaname)
deltaname++; /* skip slash */
else
deltaname = delta;
for (pce = 1; pce <= npieces; pce++)
{
sfp = open_sendmail();
if (sfp == NULL)
exit(1);
write_header(sfp, mail_alias, delta, pce, npieces);
sum = encode_body(sfp, dfp, msg_size);
write_trailer(sfp, sum);
if (!close_sendmail(sfp))
exit(1);
err("%s %d/%d sent to %s", deltaname, pce, npieces, mail_alias);
int write_error;
mk_tmp_name(tname, queue_dir, pce);
if ((qfp = fopen(tname, "w")) == NULL)
{
err("cannot open '%s' for writing", tname);
return 1;
}
write_header(qfp, mail_alias, delta, pce, npieces);
if (encode_body(qfp, dfp, msg_size, &sum))
return 1;
write_trailer(qfp, sum);
fflush(qfp);
write_error = ferror(qfp);
fclose(qfp);
if (write_error)
{
err("error writing '%s'", tname);
return 1;
}
/*
* Give the warm success message now, instead of all in a rush
* during the rename phase.
*/
err("%s %d/%d queued for %s", delta, pce, npieces, mail_alias);
}
fclose(dfp);
/*
* Rename the pieces into place. If an error occurs now, we are
* stuffed, but there is no neat way to back out. rename() should
* only fail now under extreme circumstances.
*/
for (pce = 1; pce <= npieces; pce++)
{
mk_tmp_name(tname, queue_dir, pce);
mk_queue_name(qname, queue_dir, delta, pce, npieces);
if (rename(tname, qname) < 0)
{
err("*rename: '%s' to '%s'", tname, qname);
unlink(tname);
}
}
return 0;
}
/*
* Carve our CTM delta into pieces, encode them, and drop them in the
* queue dir.
*
* Basic algorythm:
*
* - for (each piece)
* - gen. temp. file name (one which the de-queuer will ignore)
* - record in array
* - open temp. file
* - encode delta (including headers) into the temp file
* - close temp. file
* - end
* - lock queue directory
* - foreach (temp. file)
* - rename to the proper filename
* - end
* - unlock queue directory
*
* This is probably overkill, but it means that incomplete deltas
* don't get mailed, and also reduces the window for lock races
* between ctm_smail and the de-queueing process.
/*
* There may be temporary files cluttering up the queue directory.
*/
void
chop_and_queue(char *delta, off_t ctm_size, long max_msg_size, char *queue_dir, char *mail_alias)
{
int npieces, pce, len;
long msg_size, exp_size;
FILE *sfp, *dfp;
unsigned sum;
char **tempnames, *tempnam, *sn;
#define howmany(x, y) (((x) + ((y) - 1)) / (y))
/*
* Work out how many pieces we need, bearing in mind that each piece
* grows by 4/3 when encoded. We count the newlines too, but ignore
* all mail headers and piece headers. They are a "small" (almost
* constant) per message overhead that we make the user worry about. :-)
*/
exp_size = ctm_size * 4 / 3;
exp_size += howmany(exp_size, LINE_LENGTH);
npieces = howmany(exp_size, max_msg_size);
msg_size = howmany(ctm_size, npieces);
#undef howmany
/*
* allocate space for the array of filenames. Try to be portable
* by not assuming anything to do with sizeof(char *)
*/
tempnames = malloc(npieces * sizeof(char *));
if (tempnames == NULL)
clean_up_queue(char *queue_dir)
{
err("malloc for tempnames failed");
exit(1);
}
len = strlen(queue_dir) + 16;
tempnam = malloc(len);
if (tempnam == NULL)
{
err("malloc for tempnames failed");
exit(1);
}
if ((dfp = fopen(delta, "r")) == NULL)
{
err("cannot open '%s' for reading.", delta);
exit(1);
}
int pce;
char tname[PATH_MAX];
if ((sn = strrchr(delta, '/')) == NULL)
sn = delta;
else
sn++;
for (pce = 1; pce <= npieces; pce++)
{
if (snprintf(tempnam, len, "%s/.%08d-%03d", queue_dir, getpid(), pce) >= len)
err("Whoops! tempnam isn't long enough");
tempnames[pce - 1] = strdup(tempnam);
if (tempnames[pce - 1] == NULL)
err("discarding queued delta pieces");
for (pce = 1; ; pce++)
{
err("strdup failed for temp. filename");
exit(1);
mk_tmp_name(tname, queue_dir, pce);
if (unlink(tname) < 0)
break;
}
sfp = fopen(tempnam, "w");
if (sfp == NULL)
exit(1);
write_header(sfp, mail_alias, delta, pce, npieces);
sum = encode_body(sfp, dfp, msg_size);
write_trailer(sfp, sum);
if (fclose(sfp) != 0)
exit(1);
err("%s %d/%d created succesfully", sn, pce, npieces);
}
add_to_queue(queue_dir, mail_alias, delta, npieces, tempnames);
fclose(dfp);
}
/*
* MIME BASE64 encode table.
@ -288,8 +311,8 @@ static char to_b64[0x40] =
* of 4 characters encodes 3 input characters. Each output character encodes
* 6 bits. Thus 64 different characters are needed in this representation.
*/
unsigned
encode_body(FILE *sm_fp, FILE *delta_fp, long msg_size)
int
encode_body(FILE *sm_fp, FILE *delta_fp, long msg_size, unsigned *sum)
{
unsigned short cksum = 0xffff;
unsigned char *ip;
@ -344,16 +367,12 @@ encode_body(FILE *sm_fp, FILE *delta_fp, long msg_size)
if (ferror(delta_fp))
{
err("error reading input file.");
exit(1);
return 1;
}
if (ferror(sm_fp))
{
err("error writing encoded file");
exit(1);
}
*sum = cksum;
return cksum;
return 0;
}
@ -363,18 +382,11 @@ encode_body(FILE *sm_fp, FILE *delta_fp, long msg_size)
void
write_header(FILE *sfp, char *mail_alias, char *delta, int pce, int npieces)
{
char *sn;
if ((sn = strrchr(delta, '/')) == NULL)
sn = delta;
else
sn++;
fprintf(sfp, "From: owner-%s\n", mail_alias);
fprintf(sfp, "To: %s\n", mail_alias);
fprintf(sfp, "Subject: ctm-mail %s %d/%d\n\n", sn, pce, npieces);
fprintf(sfp, "Subject: ctm-mail %s %d/%d\n\n", delta, pce, npieces);
fprintf(sfp, "CTM_MAIL BEGIN %s %d %d\n", sn, pce, npieces);
fprintf(sfp, "CTM_MAIL BEGIN %s %d %d\n", delta, pce, npieces);
}
@ -390,32 +402,30 @@ write_trailer(FILE *sfp, unsigned sum)
/*
* We're terribly sorry, but the delta is too big to send.
* Returns 0 on success, 1 on failure.
*/
void
int
apologise(char *delta, off_t ctm_size, long max_ctm_size, char *mail_alias)
{
FILE *sfp;
char *sn;
sfp = open_sendmail();
if (sfp == NULL)
exit(1);
return 1;
if ((sn = strrchr(delta, '/')) == NULL)
sn = delta;
else
sn++;
fprintf(sfp, "From: %s-owner\n", mail_alias);
fprintf(sfp, "From: owner-%s\n", mail_alias);
fprintf(sfp, "To: %s\n", mail_alias);
fprintf(sfp, "Subject: ctm-notice %s\n\n", sn);
fprintf(sfp, "Subject: ctm-notice %s\n\n", delta);
fprintf(sfp, "%s is %ld bytes. The limit is %ld bytes.\n\n", sn,
fprintf(sfp, "%s is %ld bytes. The limit is %ld bytes.\n\n", delta,
(long)ctm_size, max_ctm_size);
fprintf(sfp, "You can retrieve this delta via ftpmail, or your good mate at the university.\n");
fprintf(sfp, "You can retrieve this delta via ftpmail, "
"or your good mate at the university.\n");
if (!close_sendmail(sfp))
exit(1);
return 1;
return 0;
}
@ -457,137 +467,3 @@ close_sendmail(FILE *fp)
return (status == 0);
}
/*
* Lock the queuedir so we're the only guy messing about in there.
*/
int
lock_queuedir(char *queue_dir)
{
int fp, len;
char *buffer;
struct stat sb;
len = strlen(queue_dir) + 8;
buffer = malloc(len);
if (buffer == NULL)
{
err("malloc failed in lock_queuedir");
exit(1);
}
if (snprintf(buffer, len, "%s/.lock", queue_dir) >= len)
err("Whoops. lock buffer too small in lock_queuedir");
/*
* We do our own lockfile scanning to avoid unlink races. 60
* seconds should be enough to ensure that we won't get more races
* happening between the stat and the open/flock.
*/
while (stat(buffer, &sb) == 0)
sleep(60);
if ((fp = open(buffer, O_WRONLY | O_CREAT | O_EXLOCK, 0600)) < 0)
{
err("can't open `%s' in lock_queuedir", buffer);
exit(1);
}
snprintf(buffer, len, "%8ld", getpid());
write(fp, buffer, 8);
free(buffer);
return(fp);
}
/*
* Lock the queuedir so we're the only guy messing about in there.
*/
void
free_lock(int lockf, char *queue_dir)
{
int len;
char *path;
/*
* Most important: free the lock before we do anything else!
*/
close(lockf);
len = strlen(queue_dir) + 7;
path = malloc(len);
if (path == NULL)
{
err("malloc failed in free_lock");
exit(1);
}
if (snprintf(path, len, "%s/.lock", queue_dir) >= len)
err("lock path buffer too small in free_lock");
if (unlink(path) != 0)
{
err("can't unlink lockfile `%s'", path);
exit(1);
}
free(path);
}
/* move everything into the queue directory. */
void
add_to_queue(char *queue_dir, char *mail_alias, char *delta, int npieces, char **tempnames)
{
char *queuefile, *sn;
int pce, len, lockf;
if ((sn = strrchr(delta, '/')) == NULL)
sn = delta;
else
sn++;
/* try to malloc all we need BEFORE entering the lock loop */
len = strlen(queue_dir) + strlen(sn) + 7;
queuefile = malloc(len);
if (queuefile == NULL)
{
err("can't malloc for queuefile");
exit(1);
}
/*
* We should be the only process mucking around in the queue
* directory while we add the new queue files ... it could be
* awkward if the de-queue process starts it's job while we're
* adding files ...
*/
lockf = lock_queuedir(queue_dir);
for (pce = 0; pce < npieces; pce++)
{
struct stat sb;
if (snprintf(queuefile, len, "%s/%s+%03d", queue_dir, sn, pce + 1) >= len)
err("whoops, queuefile buffer is too small");
if (stat(queuefile, &sb) == 0)
{
err("WOAH! Queue file `%s' already exists! Bailing out.", queuefile);
free_lock(lockf, queue_dir);
exit(1);
}
rename(tempnames[pce], queuefile);
}
free_lock(lockf, queue_dir);
free(queuefile);
}