(Not tested yet. I may insist that ctm be invoked with absolute path. /phk)

This patch fixes the concurrency problem, and adds a possibly useful -f switch
(which you can read about in the man page :-) ).  It also removes the absolute
path from the invocation of ctm.  I'll write a note about how to use a script
with sendmail and procmail or some such, and people can fix their PATH there.

BTW, this patch changes ctm_rmail.1, ctm_rmail.c and error.c in the ctm_rmail
directory.

Stephen.

Reviewed by:	phk
Submitted by:	Stephen McKay <syssgm@devetir.qld.gov.au>

usr.sbin/ctm/ctm_rmail/ctm_rmail.1

@@ -5,9 +5,9 @@
 .\"
 .\" Author: Stephen McKay
 .\"
-.Dd January 15, 1995
+.Dd January 24, 1995
-.Os
 .Dt CTM_MAIL 1
+.Os
 .Sh NAME
 .Nm ctm_smail, ctm_rmail
 .Nd send and receive
@@ -21,7 +21,7 @@ deltas via mail
 .Ar ctm-delta
 .Ar mail-alias
 .Nm ctm_rmail
-.Op Fl D
+.Op Fl Df
 .Op Fl l Ar log
 .Op Fl p Ar piecedir
 .Op Fl d Ar deltadir
@@ -37,14 +37,14 @@ and
 are used to distribute changes to a source tree via email.
 .Nm ctm_smail
 is given a compressed
-.Nm ctm
+.Xr ctm
 delta, and a mailing list to send it to.  It splits the delta into manageable
 pieces, encodes them as mail messages and sends them to the mailing list.
 Each recipient uses
 .Nm ctm_rmail
 (either manually or automatically) to decode and reassemble the delta, and
 optionally call
-.Xr ctm 1
+.Xr ctm
 to apply it to the source tree.
 At the moment,
 only two source trees are distributed, and both by the same site.  These are
@@ -96,7 +96,7 @@ Collect pieces of deltas in this directory.  Each piece corresponds to a
 single mail message.  Pieces are removed when complete deltas are built.
 If this flag is not given, no input files will be read, but completed
 deltas may still be applied with
-.Xr ctm 1
+.Xr ctm
 if the
 .Fl b
 flag is given.
@@ -120,11 +120,34 @@ file in
 does not exist).
 .It Fl D
 Delete deltas after successful application by
-.Xr ctm 1 .
+.Xr ctm .
 It is probably a good idea to avoid this flag (and keep all the deltas)
 as one of the possible future enhancements to
-.Xr ctm 1
+.Xr ctm
 is the ability to recover small groups of files from a full set of deltas.
+.It Fl f
+Fork and execute in the background while applying deltas with
+.Xr ctm .
+This is useful when automatically invoking
+.Nm ctm_rmail
+from
+.Xr sendmail
+because
+.Xr ctm
+can take a very long time to complete, causing other people's mail to
+be delayed, and can in theory cause spurious
+mail retransmission due to the remote
+.Xr sendmail
+timing out, or even termination of
+.Nm ctm_rmail
+by mail filters such as
+.Xr "MH's"
+.Xr slocal .
+Don't worry about zillions of background
+.Xr ctm
+processes loading your machine, since locking is used to prevent more than one
+.Xr ctm
+invocation at a time.
 .El
 .Pp
 The file arguments (or
@@ -132,6 +155,15 @@ The file arguments (or
 if there are none) are scanned for delta pieces.  Multiple delta pieces
 can be read from a single file, so an entire maildrop can be scanned
 and processed with a single command.
+.Pp
+It is safe to invoke
+.Nm ctm_rmail
+multiple times concurrently (with different input files),
+as might happen when
+.Xr sendmail
+.nh
+is delivering mail asynchronously.  This is because locking is used to
+keep things orderly.
 .Sh FILE FORMAT
 Following are the important parts of an actual (very small) delta piece:
 .Bd -literal
@@ -174,7 +206,7 @@ You are then on your own!
 To send delta 32 of
 .Em src-cur
 to a group of wonderful code hackers known to
-.Xr sendmail 8
+.Xr sendmail
 as
 .Em src-guys ,
 limiting the mail size to roughly 60000 bytes, you could use:
@@ -229,13 +261,15 @@ the window for mischief is quite small.
 is careful to write only to the directories given to it (by not believing any
 .Dq /
 characters in the delta name), and the latest
-.Nm ctm
+.Xr ctm
-disallows absolute pathnames in files it manipulates, so the worst you
+disallows absolute pathnames and
+.Dq \&\.\.
+in files it manipulates, so the worst you
 could lose are a few source tree files (recoverable from your deltas).
 Since
-.Nm ctm
+.Xr ctm
 requires that a
-.Nm md5
+.Xr md5
 checksum match before it touches a file, only fellow
 source recipients would be able to generate a fake delta, and they're such
 nice folk that they wouldn't even think of it! :-)
@@ -273,7 +307,7 @@ is expected to be called from a mail transfer program, and thus signals
 failure only when the input mail message should be bounced (preferably into
 your regular maildrop, not back to the sender).  In short, failure to
 apply a completed delta with
-.Nm ctm
+.Xr ctm
 is not considered an error important enough to bounce the mail, and
 .Nm ctm_rmail
 returns an exit status of 0.
@@ -293,10 +327,20 @@ ctm_rmail: src-cur.0250.gz 2/2 stored
 ctm_rmail: src-cur.0250.gz complete
 .Ed
 .Pp
+If any of the input files do not contain a valid delta piece,
+.Nm ctm_rmail
+will report:
+.Bd -literal -offset indent
+ctm_rmail: message contains no delta
+.Ed
+.sp \n(Ppu
+and return an exit status of 1.  You can use this to redirect wayward messages
+back into your real mailbox if your mail filter goes wonky.
+.Pp
 These messages go to
 .Em stderr
 or to the log file.  Messages from
-.Nm ctm
+.Xr ctm
 turn up here too.  Error messages should be self explanatory.
 .\" The next request is for sections 2 and 3 error and signal handling only.
 .\" .Sh ERRORS

usr.sbin/ctm/ctm_rmail/ctm_rmail.c

@@ -17,6 +17,8 @@
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <fcntl.h>
+#include <limits.h>
 #include "error.h"
 #include "options.h"
 
@@ -30,7 +32,9 @@ int delete_after = 0;		/* Delete deltas after ctm applies them. */
 void apply_complete(void);
 int read_piece(char *input_file);
 int combine_if_complete(char *delta, int pce, int npieces);
+int combine(char *delta, int npieces, char *dname, char *pname, char *tname);
 int decode_line(char *line, char *out_buf);
+int lock_file(char *name);
 
 /*
  * If given a '-p' flag, read encoded delta pieces from stdin or file
@@ -51,11 +55,13 @@ main(int argc, char **argv)
     {
     char *log_file = NULL;
     int status = 0;
+    int fork_ctm = 0;
 
     err_prog_name(argv[0]);
 
-    OPTIONS("[-D] [-p piecedir] [-d deltadir] [-b basedir] [-l log] [file ...]")
+    OPTIONS("[-Df] [-p piecedir] [-d deltadir] [-b basedir] [-l log] [file ...]")
 	FLAG('D', delete_after)
+	FLAG('f', fork_ctm)
 	STRING('p', piece_dir)
 	STRING('d', delta_dir)
 	STRING('b', base_dir)
@@ -71,6 +77,9 @@ main(int argc, char **argv)
     if (log_file != NULL)
 	err_set_log(log_file);
 
+    /*
+     * Digest each file in turn, or just stdin if no files were given.
+     */
     if (argc <= 1)
 	{
 	if (piece_dir != NULL)
@@ -82,8 +91,20 @@ main(int argc, char **argv)
 	    status |= read_piece(*argv);
 	}
 
+    /*
+     * Maybe it's time to look for and apply completed deltas with ctm.
+     *
+     * Shall we report back to sendmail immediately, and let a child do
+     * the work?  Sendmail will be waiting for us to complete, delaying
+     * other mail, and possibly some intermediate process (like MH slocal)
+     * will terminate us if we take too long!
+     *
+     * If fork() fails, it's unlikely we'll be able to run ctm, so give up.
+     * Also, the child exit status is unimportant.
+     */
     if (base_dir != NULL)
-	apply_complete();
+	if (!fork_ctm || fork() == 0)
+	    apply_complete();
 
     return status;
     }
@@ -109,23 +130,42 @@ void
 apply_complete()
     {
     int i, dn;
+    int lfd;
     FILE *fp, *ctm;
     struct stat sb;
     char class[20];
     char delta[30];
-    char fname[1000];
-    char buf[2000];
     char junk[2];
-    char here[1000];
+    char fname[PATH_MAX];
+    char here[PATH_MAX];
+    char buf[PATH_MAX*2];
 
+    /*
+     * Grab a lock on the ctm mutex file so that we can be sure we are
+     * working alone, not fighting another ctm_rmail!
+     */
+    strcpy(fname, delta_dir);
+    strcat(fname, "/.mutex_apply");
+    if ((lfd = lock_file(fname)) < 0)
+	return;
+
+    /*
+     * Find out which delta ctm needs next.
+     */
     sprintf(fname, "%s/%s", base_dir, CTM_STATUS);
     if ((fp = fopen(fname, "r")) == NULL)
+	{
+	close(lfd);
 	return;
+	}
 
     i = fscanf(fp, "%s %d %c", class, &dn, junk);
     fclose(fp);
     if (i != 2)
+	{
+	close(lfd);
 	return;
+	}
 
     /*
      * We might need to convert the delta filename to an absolute pathname.
@@ -151,14 +191,13 @@ apply_complete()
 	mk_delta_name(fname, delta);
 
 	if (stat(fname, &sb) < 0)
-	    return;
+	    break;
 
-	sprintf(buf, "(cd %s && /usr/sbin/ctm %s%s) 2>&1", 
+	sprintf(buf, "(cd %s && ctm %s%s) 2>&1", base_dir, here, fname);
-	    base_dir, here, fname);
 	if ((ctm = popen(buf, "r")) == NULL)
 	    {
 	    err("ctm failed to apply %s", delta);
-	    return;
+	    break;
 	    }
 
 	while (fgets(buf, sizeof(buf), ctm) != NULL)
@@ -172,7 +211,7 @@ apply_complete()
 	if (pclose(ctm) != 0)
 	    {
 	    err("ctm failed to apply %s", delta);
-	    return;
+	    break;
 	    }
 
 	if (delete_after)
@@ -180,6 +219,11 @@ apply_complete()
 
 	err("%s applied%s", delta, delete_after ? " and deleted" : "");
 	}
+
+    /*
+     * Closing the lock file clears the lock.
+     */
+    close(lfd);
     }
 
 
@@ -204,6 +248,7 @@ read_piece(char *input_file)
     int status = 0;
     FILE *ifp, *ofp = 0;
     int decoding = 0;
+    int got_one = 0;
     int line_no = 0;
     int i, n;
     int pce, npieces;
@@ -212,8 +257,8 @@ read_piece(char *input_file)
     char out_buf[200];
     char line[200];
     char delta[30];
-    char pname[1000];
+    char pname[PATH_MAX];
-    char tname[1000];
+    char tname[PATH_MAX];
     char junk[2];
 
     ifp = stdin;
@@ -241,8 +286,15 @@ read_piece(char *input_file)
 	    while ((s = strchr(delta, '/')) != NULL)
 		*s = '_';
 
-	    mk_piece_name(pname, delta, pce, npieces);
+	    got_one++;
-	    sprintf(tname,"%s.%d.tmp",pname,getpid());
+	    strcpy(tname, piece_dir);
+	    strcat(tname, "/p.XXXXXX");
+	    if (mktemp(tname) == NULL)
+		{
+		err("*mktemp: '%s'", tname);
+		status++;
+		continue;
+		}
 	    if ((ofp = fopen(tname, "w")) == NULL)
 		{
 		err("cannot open '%s' for writing", tname);
@@ -282,9 +334,11 @@ read_piece(char *input_file)
 		continue;
 		}
 
+	    mk_piece_name(pname, delta, pce, npieces);
 	    if (rename(tname, pname) < 0)
 		{
-		err("error renaming %s to %s",tname,pname);
+		err("*rename: '%s' to '%s'", tname, pname);
+		err("%s %d/%d lost!", delta, pce, npieces);
 		unlink(tname);
 		status++;
 		continue;
@@ -301,13 +355,13 @@ read_piece(char *input_file)
 	 * Must be a line of encoded data.  Decode it, sum it, and save it.
 	 */
 	n = decode_line(line, out_buf);
-	if (n < 0)
+	if (n <= 0)
 	    {
 	    err("line %d: illegal character: '%c'", line_no, line[-n]);
 	    err("%s %d/%d discarded", delta, pce, npieces);
 
 	    fclose(ofp);
-	    unlink(pname);
+	    unlink(tname);
 
 	    status++;
 	    decoding = 0;
@@ -326,7 +380,7 @@ read_piece(char *input_file)
 	err("%s %d/%d discarded", delta, pce, npieces);
 
 	fclose(ofp);
-	unlink(pname);
+	unlink(tname);
 
 	status++;
 	}
@@ -340,6 +394,12 @@ read_piece(char *input_file)
     if (input_file != NULL)
 	fclose(ifp);
 
+    if (!got_one)
+	{
+	err("message contains no delta");
+	status++;
+	}
+
     return (status != 0);
     }
 
@@ -351,32 +411,19 @@ read_piece(char *input_file)
 int
 combine_if_complete(char *delta, int pce, int npieces)
     {
-    int i;
+    int i, e;
-    FILE *dfp, *pfp;
+    int lfd;
-    int c;
     struct stat sb;
-    char pname[1000];
+    char pname[PATH_MAX];
-    char dname[1000];
+    char dname[PATH_MAX];
+    char tname[PATH_MAX];
 
     /*
-     * All here?
+     * We can probably just rename() it into place if it is a small delta.
-     */
-    for (i = 1; i <= npieces; i++)
-	{
-	if (i == pce)
-	    continue;
-	mk_piece_name(pname, delta, i, npieces);
-	if (stat(pname, &sb) < 0)
-	    return 1;
-	}
-
-    mk_delta_name(dname, delta);
-
-    /*
-     * We can probably just rename() it in to place if it is a small delta.
      */
     if (npieces == 1)
 	{
+	mk_delta_name(dname, delta);
 	mk_piece_name(pname, delta, 1, 1);
 	if (rename(pname, dname) == 0)
 	    {
@@ -385,14 +432,70 @@ combine_if_complete(char *delta, int pce, int npieces)
 	    }
 	}
 
-    if ((dfp = fopen(dname, "w")) == NULL)
+    /*
+     * Grab a lock on the reassembly mutex file so that we can be sure we are
+     * working alone, not fighting another ctm_rmail!
+     */
+    strcpy(tname, delta_dir);
+    strcat(tname, "/.mutex_build");
+    if ((lfd = lock_file(tname)) < 0)
+	return 0;
+
+    /*
+     * Are all of the pieces present?  Of course the current one is,
+     * unless all pieces are missing because another ctm_rmail has
+     * processed them already.
+     */
+    for (i = 1; i <= npieces; i++)
 	{
-	err("cannot open '%s' for writing", dname);
+	if (i == pce)
+	    continue;
+	mk_piece_name(pname, delta, i, npieces);
+	if (stat(pname, &sb) < 0)
+	    {
+	    close(lfd);
+	    return 1;
+	    }
+	}
+
+    /*
+     * Stick them together.  Let combine() use our file name buffers, since
+     * we're such good buddies. :-)
+     */
+    e = combine(delta, npieces, dname, pname, tname);
+    close(lfd);
+    return e;
+    }
+
+
+/*
+ * Put the pieces together to form a delta.
+ * Returns 1 on success, and 0 on failure.
+ * Note: dname, pname, and tname are room for some file names that just
+ * happened to by lying around in the calling routine.  Waste not, want not!
+ */
+int
+combine(char *delta, int npieces, char *dname, char *pname, char *tname)
+    {
+    FILE *dfp, *pfp;
+    int i, n, e;
+    char buf[BUFSIZ];
+
+    strcpy(tname, delta_dir);
+    strcat(tname, "/d.XXXXXX");
+    if (mktemp(tname) == NULL)
+	{
+	err("*mktemp: '%s'", tname);
+	return 0;
+	}
+    if ((dfp = fopen(tname, "w")) == NULL)
+	{
+	err("cannot open '%s' for writing", tname);
 	return 0;
 	}
 
     /*
-     * Ok, the hard way.  Reconstruct the delta by reading each piece in order.
+     * Reconstruct the delta by reading each piece in order.
      */
     for (i = 1; i <= npieces; i++)
 	{
@@ -401,22 +504,38 @@ combine_if_complete(char *delta, int pce, int npieces)
 	    {
 	    err("cannot open '%s' for reading", pname);
 	    fclose(dfp);
-	    unlink(dname);
+	    unlink(tname);
 	    return 0;
 	    }
-	while ((c = getc(pfp)) != EOF)
+	while ((n = fread(buf, sizeof(char), sizeof(buf), pfp)) != 0)
-	    putc(c, dfp);
+	    fwrite(buf, sizeof(char), n, dfp);
+	e = ferror(pfp);
 	fclose(pfp);
+	if (e)
+	    {
+	    err("error reading '%s'", pname);
+	    fclose(dfp);
+	    unlink(tname);
+	    return 0;
+	    }
 	}
     fflush(dfp);
-    if (ferror(dfp))
+    e = ferror(dfp);
+    fclose(dfp);
+    if (e)
 	{
-	err("error writing '%s'", dname);
+	err("error writing '%s'", tname);
-	fclose(dfp);
+	unlink(tname);
-	unlink(dname);
+	return 0;
+	}
+
+    mk_delta_name(dname, delta);
+    if (rename(tname, dname) < 0)
+	{
+	err("*rename: '%s' to '%s'", tname, dname);
+	unlink(tname);
 	return 0;
 	}
-    fclose(dfp);
 
     /*
      * Throw the pieces away.
@@ -424,7 +543,8 @@ combine_if_complete(char *delta, int pce, int npieces)
     for (i = 1; i <= npieces; i++)
 	{
 	mk_piece_name(pname, delta, i, npieces);
-	unlink(pname);
+	if (unlink(pname) < 0)
+	    err("*unlink: '%s'", pname);
 	}
 
     err("%s complete", delta);
@@ -500,3 +620,28 @@ decode_line(char *line, char *out_buf)
     else
 	return -(ip - (unsigned char *)line);
     }
+
+
+/*
+ * Create and lock the given file.
+ *
+ * Clearing the lock is as simple as closing the file descriptor we return.
+ */
+int
+lock_file(char *name)
+    {
+    int lfd;
+
+    if ((lfd = open(name, O_WRONLY|O_CREAT, 0600)) < 0)
+	{
+	err("*open: '%s'", name);
+	return -1;
+	}
+    if (flock(lfd, LOCK_EX) < 0)
+	{
+	close(lfd);
+	err("*flock: '%s'", name);
+	return -1;
+	}
+    return lfd;
+    }

usr.sbin/ctm/ctm_rmail/error.c

@@ -1,7 +1,22 @@
+/*
+ * Routines for logging error messages or other informative messages.
+ *
+ * Log messages can easily contain the program name, a time stamp, system
+ * error messages, and arbitrary printf-style strings, and can be directed
+ * to stderr or a log file.
+ *
+ * Author: Stephen McKay
+ *
+ * NOTICE: This is free software.  I hope you get some use from this program.
+ * In return you should think about all the nice people who give away software.
+ * Maybe you should write some free software too.
+ */
+
 #include <stdio.h>
 #include <string.h>
 #include <stdarg.h>
 #include <time.h>
+#include <errno.h>
 #include "error.h"
 
 static FILE *error_fp = NULL;
@@ -38,6 +53,9 @@ err_prog_name(char *name)
 
 /*
  * Log an error.
+ *
+ * A leading '*' in the message format means we want the system errno
+ * decoded and appended.
  */
 void
 err(char *fmt, ...)
@@ -46,6 +64,8 @@ err(char *fmt, ...)
     time_t now;
     struct tm *tm;
     FILE *fp;
+    int x = errno;
+    int want_errno;
 
     if ((fp = error_fp) == NULL)
 	{
@@ -61,10 +81,17 @@ err(char *fmt, ...)
 	    tm->tm_mon+1, tm->tm_mday, tm->tm_hour, tm->tm_min);
 	}
 
+    want_errno = 0;
+    if (*fmt == '*')
+	want_errno++, fmt++;
+
     va_start(ap, fmt);
     vfprintf(fp, fmt, ap);
     va_end(ap);
 
+    if (want_errno)
+	fprintf(fp, ": %s", strerror(x));
+
     fprintf(fp, "\n");
     fflush(fp);
     }