pexec

commit 3b39dcfbbdcc324415e8991dd2d5c6619b8066c8
parent 33677e7d503a945df47430563753fcd530975690
Author: sin <sin@2f30.org>
Date:   Fri, 23 Mar 2018 15:56:22 +0000

Move pexec code into its own function

Diffstat:
M
pexec.c
 | 
50
+++++++++++++++++++++++++++++---------------------

1 file changed, 29 insertions(+), 21 deletions(-)
diff --git a/pexec.c b/pexec.c
@@ -32,12 +32,6 @@
 
 char *argv0;
 
-static int
-memfd_create(const char *name, unsigned int flags)
-{
-	return syscall(__NR_memfd_create, name, flags);
-}
-
 static ssize_t
 xread(int fd, void *buf, size_t nbytes)
 {
@@ -78,6 +72,33 @@ xwrite(int fd, const void *buf, size_t nbytes)
 	return total;
 }
 
+static int
+memfd_create(const char *name, unsigned int flags)
+{
+	return syscall(__NR_memfd_create, name, flags);
+}
+
+void
+pexec(int ifd, char *argv[], char *envp[])
+{
+	char buf[BUFSIZ];
+	ssize_t n;
+	int fd;
+
+	fd = memfd_create(argv[0], 0);
+	if (fd < 0)
+		err(1, "memfd_create");
+
+	if (fchmod(fd, 0755) < 0)
+		err(1, "fchmod");
+
+	while ((n = xread(ifd, buf, BUFSIZ)) > 0)
+		xwrite(fd, buf, n);
+
+	if (fexecve(fd, argv, envp) < 0)
+		err(1, "fexecve");
+}
+
 static void
 usage(void)
 {
@@ -89,9 +110,7 @@ int
 main(int argc, char *argv[])
 {
 	char *envp[] = { NULL };
-	char buf[BUFSIZ];
-	ssize_t n;
-	int fd, iflag = 0;
+	int iflag = 0;
 
 	ARGBEGIN {
 	case 'i':
@@ -104,18 +123,7 @@ main(int argc, char *argv[])
 	if (argc == 0)
 		usage();
 
-	fd = memfd_create(argv[0], 0);
-	if (fd < 0)
-		err(1, "memfd_create");
-
-	if (fchmod(fd, 0755) < 0)
-		err(1, "fchmod");
-
-	while ((n = xread(STDIN_FILENO, buf, BUFSIZ)) > 0)
-		xwrite(fd, buf, n);
-
 	extern char **environ;
-	if (fexecve(fd, argv, iflag ? envp : environ) < 0)
-		err(1, "fexecve");
+	pexec(STDIN_FILENO, argv, iflag ? envp : environ);
 	/* unreachable */
 }