Thanks to John Cummings.

src/cmd/upas/common/mail.c

@@ -0,0 +1,57 @@
+#include "common.h"
+
+/* format of REMOTE FROM lines */
+char *REMFROMRE =
+	"^>?From[ \t]+((\".*\")?[^\" \t]+?(\".*\")?[^\" \t]+?)[ \t]+(.+)[ \t]+remote[ \t]+from[ \t]+(.*)\n$";
+int REMSENDERMATCH = 1;
+int REMDATEMATCH = 4;
+int REMSYSMATCH = 5;
+
+/* format of LOCAL FROM lines */
+char *FROMRE =
+	"^>?From[ \t]+((\".*\")?[^\" \t]+?(\".*\")?[^\" \t]+?)[ \t]+(.+)\n$";
+int SENDERMATCH = 1;
+int DATEMATCH = 4;
+
+/* output a unix style local header */
+int
+print_header(Biobuf *fp, char *sender, char *date)
+{
+	return Bprint(fp, "From %s %s\n", sender, date);
+}
+
+/* output a unix style remote header */
+int
+print_remote_header(Biobuf *fp, char *sender, char *date, char *system)
+{
+	return Bprint(fp, "From %s %s remote from %s\n", sender, date, system);
+}
+
+/* parse a mailbox style header */
+int
+parse_header(char *line, String *sender, String *date)
+{
+	if (!IS_HEADER(line))
+		return -1;
+	line += sizeof("From ") - 1;
+	s_restart(sender);
+	while(*line==' '||*line=='\t')
+		line++;
+	if(*line == '"'){
+		s_putc(sender, *line++);
+		while(*line && *line != '"')
+			s_putc(sender, *line++);
+		s_putc(sender, *line++);
+	} else {
+		while(*line && *line != ' ' && *line != '\t')
+			s_putc(sender, *line++);
+	}
+	s_terminate(sender);
+	s_restart(date);
+	while(*line==' '||*line=='\t')
+		line++;
+	while(*line)
+		s_putc(date, *line++);
+	s_terminate(date);
+	return 0;
+}

src/cmd/upas/common/makefile

@@ -0,0 +1,18 @@
+CFLAGS=${UNIX} -g -I. -I../libc -I../common -I/usr/include ${SCFLAGS}
+OBJS=mail.o aux.o string.o ${SYSOBJ}
+AR=ar
+.c.o: ; ${CC} -c ${CFLAGS} $*.c
+
+common.a: ${OBJS}
+	${AR} cr common.a ${OBJS}
+	-ranlib common.a
+
+aux.o:		aux.h string.h mail.h
+string.o:	string.h mail.h
+mail.o:		mail.h
+syslog.o:	sys.h
+mail.h:		sys.h
+
+clean:
+	-rm -f *.[oO] core a.out *.a *.sL common.a
+

src/cmd/upas/common/mkfile

@@ -0,0 +1,20 @@
+<$PLAN9/src/mkhdr
+
+LIB=libcommon.a
+
+OFILES=aux.$O\
+	become.$O\
+	mail.$O\
+	process.$O\
+	libsys.$O\
+	config.$O\
+	appendfiletombox.$O\
+
+HFILES=common.h\
+	sys.h\
+
+<$PLAN9/src/mklib
+
+nuke:V:
+	mk clean
+	rm -f libcommon.a

src/cmd/upas/common/process.c

@@ -0,0 +1,175 @@
+#include "common.h"
+
+/* make a stream to a child process */
+extern stream *
+instream(void)
+{
+	stream *rv;
+	int pfd[2];
+
+	if ((rv = (stream *)malloc(sizeof(stream))) == 0)
+		return 0;
+	memset(rv, 0, sizeof(stream));
+	if (pipe(pfd) < 0)
+		return 0;
+	if(Binit(&rv->bb, pfd[1], OWRITE) < 0){
+		close(pfd[0]);
+		close(pfd[1]);
+		return 0;
+	}
+	rv->fp = &rv->bb;
+	rv->fd = pfd[0];	
+	return rv;
+}
+
+/* make a stream from a child process */
+extern stream *
+outstream(void)
+{
+	stream *rv;
+	int pfd[2];
+
+	if ((rv = (stream *)malloc(sizeof(stream))) == 0)
+		return 0;
+	memset(rv, 0, sizeof(stream));
+	if (pipe(pfd) < 0)
+		return 0;
+	if (Binit(&rv->bb, pfd[0], OREAD) < 0){
+		close(pfd[0]);
+		close(pfd[1]);
+		return 0;
+	}
+	rv->fp = &rv->bb;
+	rv->fd = pfd[1];
+	return rv;
+}
+
+extern void
+stream_free(stream *sp)
+{
+	int fd;
+
+	close(sp->fd);
+	fd = Bfildes(sp->fp);
+	Bterm(sp->fp);
+	close(fd);
+	free((char *)sp);
+}
+
+/* start a new process */
+extern process *
+noshell_proc_start(char **av, stream *inp, stream *outp, stream *errp, int newpg, char *who)
+{
+	process *pp;
+	int i, n;
+
+	if ((pp = (process *)malloc(sizeof(process))) == 0) {
+		if (inp != 0)
+			stream_free(inp);
+		if (outp != 0)
+			stream_free(outp);
+		if (errp != 0)
+			stream_free(errp);
+		return 0;
+	}
+	pp->std[0] = inp;
+	pp->std[1] = outp;
+	pp->std[2] = errp;
+	switch (pp->pid = fork()) {
+	case -1:
+		proc_free(pp);
+		return 0;
+	case 0:
+		if(newpg)
+			sysdetach();
+		for (i=0; i<3; i++)
+			if (pp->std[i] != 0){
+				close(Bfildes(pp->std[i]->fp));
+				while(pp->std[i]->fd < 3)
+					pp->std[i]->fd = dup(pp->std[i]->fd, -1);
+			}
+		for (i=0; i<3; i++)
+			if (pp->std[i] != 0)
+				dup(pp->std[i]->fd, i);
+		for (n = sysfiles(); i < n; i++)
+			close(i);
+		if(who) {
+			fprint(2,"process.c: trying to become(%s,%s)\n",av,who);
+			// jpc become(av, who);
+		}
+		exec(av[0], av);
+		perror("proc_start");
+		exits("proc_start");
+	default:
+		for (i=0; i<3; i++)
+			if (pp->std[i] != 0) {
+				close(pp->std[i]->fd);
+				pp->std[i]->fd = -1;
+			}
+		return pp;
+	}
+}
+
+/* start a new process under a shell */
+extern process *
+proc_start(char *cmd, stream *inp, stream *outp, stream *errp, int newpg, char *who)
+{
+	char *av[4];
+
+	av[0] = unsharp(SHELL);
+	av[1] = "-c";
+	av[2] = cmd;
+	av[3] = 0;
+	return noshell_proc_start(av, inp, outp, errp, newpg, who);
+}
+
+/* wait for a process to stop */
+extern int
+proc_wait(process *pp)
+{
+	Waitmsg *status;
+	char err[Errlen];
+
+	for(;;){
+		status = wait();
+		if(status == nil){
+			errstr(err, sizeof(err));
+			if(strstr(err, "interrupt") == 0)
+				break;
+		}
+		if (status->pid==pp->pid)
+			break;
+	}
+	pp->pid = -1;
+	if(status == nil)
+		pp->status = -1;
+	else
+		pp->status = status->msg[0];
+	pp->waitmsg = status;
+	return pp->status;
+}
+
+/* free a process */
+extern int
+proc_free(process *pp)
+{
+	int i;
+
+	if(pp->std[1] == pp->std[2])
+		pp->std[2] = 0;		/* avoid freeing it twice */
+	for (i = 0; i < 3; i++)
+		if (pp->std[i])
+			stream_free(pp->std[i]);
+	if (pp->pid >= 0)
+		proc_wait(pp);
+	free(pp->waitmsg);
+	free((char *)pp);
+	return 0;
+}
+
+/* kill a process */
+extern int
+proc_kill(process *pp)
+{
+	return syskill(pp->pid);
+}

src/cmd/upas/common/sys.h

@@ -0,0 +1,85 @@
+/*
+ * System dependent header files for research
+ */
+
+#include <u.h>
+#include <libc.h>
+#include <regexp.h>
+#include <bio.h>
+#include "libString.h"   /* jpc String.h -> libString.h */
+
+/*
+ *  for the lock routines in libsys.c
+ */
+typedef struct Mlock	Mlock;
+struct Mlock {
+	int fd;
+	int pid;
+	String *name;
+};
+
+/*
+ *  from config.c
+ */
+extern char *MAILROOT;	/* root of mail system */
+extern char *UPASLOG;	/* log directory */
+extern char *UPASLIB;	/* upas library directory */
+extern char *UPASBIN;	/* upas binary directory */
+extern char *UPASTMP;	/* temporary directory */
+extern char *SHELL;	/* path name of shell */
+extern char *POST;	/* path name of post server addresses */
+extern int MBOXMODE;	/* default mailbox protection mode */
+
+/*
+ *  files in libsys.c
+ */
+extern char	*sysname_read(void);
+extern char	*alt_sysname_read(void);
+extern char	*domainname_read(void);
+extern char	**sysnames_read(void);
+extern char	*getlog(void);
+extern char	*thedate(void);
+extern Biobuf	*sysopen(char*, char*, ulong);
+extern int	sysopentty(void);
+extern int	sysclose(Biobuf*);
+extern int	sysmkdir(char*, ulong);
+extern int	syschgrp(char*, char*);
+extern Mlock	*syslock(char *);
+extern void	sysunlock(Mlock *);
+extern void	syslockrefresh(Mlock *);
+extern int	e_nonexistent(void);
+extern int	e_locked(void);
+extern long	sysfilelen(Biobuf*);
+extern int	sysremove(char*);
+extern int	sysrename(char*, char*);
+extern int	sysexist(char*);
+extern int	sysisdir(char*);
+extern int	syskill(int);
+extern int	syskillpg(int);
+extern int	syscreate(char*, int, ulong);
+extern Mlock	*trylock(char *);
+extern void	exit9(int);
+extern void	pipesig(int*);
+extern void	pipesigoff(void);
+extern int	holdon(void);
+extern void	holdoff(int);
+extern int	syscreatelocked(char*, int, int);
+extern int	sysopenlocked(char*, int);
+extern int	sysunlockfile(int);
+extern int	sysfiles(void);
+extern int 	become(char**, char*);
+extern int	sysdetach(void);
+extern int	sysdirreadall(int, Dir**);
+extern String	*username(String*);
+extern char*	remoteaddr(int, char*);
+extern int	creatembox(char*, char*);
+
+extern String	*readlock(String*);
+extern char	*homedir(char*);
+extern String	*mboxname(char*, String*);
+extern String	*deadletter(String*);
+
+/*
+ *  maximum size for a file path
+ */
+#define MAXPATHLEN 128