ego uses fork/exec too, so factor out the new system() code from ack and use it

there.

modules/src/system/build.lua

@@ -8,6 +8,7 @@ clibrary {
 		"./rename.c", "./seek.c", "./stop.c", "./system.c",
 		--"./unlock.c”,”./tmpdir.c”,
 		"./write.c",
+		"./syssystem.c",
 	},
 	hdrs = { "./system.h" },
 }

modules/src/system/syssystem.c

@@ -0,0 +1,42 @@
+#include <stdlib.h>
+#include <string.h>
+#include "system.h"
+
+int sys_system(const char* prog, const char* const* arglist)
+{
+	/* Calculate the maximum length of the command line. */
+
+	int len = strlen(prog);
+	for (const char* const* arg = arglist+1; *arg; arg++)
+		len += strlen(*arg) * 2 + 1;
+
+	/* Now actually build the command line. */
+
+	char* cmdline = malloc(len + 1);
+	strcpy(cmdline, prog);
+	char* p = cmdline + strlen(prog);
+
+	for (const char* const* arg = arglist+1; *arg; arg++)
+	{
+		const char* word = *arg;
+		*p++ = ' ';
+
+		for (;;)
+		{
+			char c = *word++;
+			if (!c)
+				break;
+			if ((c == ' ') || (c == '\"') || (c == '\''))
+				*p++ = '\\';
+			*p++ = c;
+		}
+	}
+
+	*p = 0;
+
+	int status = system(cmdline);
+
+	free(cmdline);
+	return status;
+}
+

modules/src/system/system.h

@@ -48,6 +48,8 @@ off_t sys_filesize(char *);
 int sys_chmode(char *, int);
 /* Return the temporary directory location */
 char* sys_gettmpdir(void);
+/* Call another program. */
+int sys_system(const char* prog, const char* const* argv);
 #if 0
 int sys_lock(char *);
 int sys_unlock(char *);

util/ack/build.lua

@@ -34,6 +34,7 @@ cprogram {
 	deps = {
 		"h+emheaders",
 		"h+local",
+		"modules/src/system+lib",
 		"./ack.h",
 		"./data.h",
 		"./dmach.h",

util/ack/run.c

@@ -15,6 +15,7 @@
 #include "grows.h"
 #include "data.h"
 #include <signal.h>
+#include "system.h"
 
 #ifndef NORCSID
 static char rcs_id[] = "$Id$";
@@ -84,40 +85,6 @@ int runphase(trf* phase)
 	return result;
 }
 
-static char* build_command_line(const char* prog)
-{
-	/* Calculate the maximum length of the command line. */
-
-	int len = strlen(prog);
-	for (int i = 1; i < (argcount - 1); i++)
-		len += strlen(arglist[i]) * 2 + 1;
-
-	/* Now actually build the command line. */
-
-	char* cmdline = malloc(len + 1);
-	strcpy(cmdline, prog);
-	char* p = cmdline + strlen(prog);
-
-	for (int i = 1; i < (argcount - 1); i++)
-	{
-		const char* word = arglist[i];
-		*p++ = ' ';
-
-		for (;;)
-		{
-			char c = *word++;
-			if (!c)
-				break;
-			if ((c == ' ') || (c == '\"') || (c == '\''))
-				*p++ = '\\';
-			*p++ = c;
-		}
-	}
-
-	*p = 0;
-	return cmdline;
-}
-
 static int run_exec(trf* phase, const char* prog)
 {
 	int status, child, waitchild;
@@ -159,9 +126,7 @@ static int run_exec(trf* phase, const char* prog)
 		}
 	}
 
-	char* cmdline = build_command_line(prog);
-	status = system(cmdline);
-	free(cmdline);
+	status = sys_system(prog, arglist);
 
 	if (oldstdin != -1)
 	{

util/ego/em_ego/em_ego.c

@@ -11,7 +11,6 @@
 #include <unistd.h>
 #include <signal.h>
 #include <sys/types.h>
-#include <sys/wait.h>
 #include <string.h>
 #include <limits.h>
 #include "em_path.h"
@@ -281,7 +280,7 @@ static void
 			if (descr_file)
 			{
 				phargs[argc++] = "-M";
-				phargs[argc++] = descr_file;
+				phargs[argc++] = (char*) descr_file;
 			}
 
 			for (i=0; i<nphase_args; i++)
@@ -291,12 +290,7 @@ static void
 			break;
 		}
 	}
-	if ((pid = fork()) < 0)
-	{
-		fatal("Could not fork");
-	}
-	else if (pid == 0)
-	{
+
 	if (v_flag)
 	{
 		register int i = 0;
@@ -308,14 +302,8 @@ static void
 		}
 		fprint(STDERR, "\n");
 	}
-		(void)execv(phargs[0], phargs);
-		fatal("Could not exec %s", phargs[0]);
-		sys_stop(S_EXIT);
-	}
-	else
-	{
-		while (wait(&status) != pid) /* nothing */
-			;
+
+	status = sys_system(phargs[0], (const char* const*) phargs);
 	if ((status & 0177) != 0)
 	{
 		fatal("%s got a unix signal", phargs[0]);
@@ -326,7 +314,6 @@ static void
 		sys_stop(S_EXIT);
 	}
 }
-}
 
 int main(int argc, char* argv[])
 {