A number of minor corrections to the support for external compression

programs:
  * Support platforms that have fork() but not vfork()
  * Don't write(), select(), or poll() against closed file descriptors

3 files changed, 45 insertions, 13 deletions

diff --git a/lib/libarchive/archive_read_support_compression_program.c b/lib/libarchive/archive_read_support_compression_program.c
index 5f6cb46..5d92b90 100644
--- a/lib/libarchive/archive_read_support_compression_program.c
+++ b/lib/libarchive/archive_read_support_compression_program.c
@@ -28,7 +28,8 @@ __FBSDID("$FreeBSD$");
 
 
 /* This capability is only available on POSIX systems. */
-#if !defined(HAVE_PIPE) || !defined(HAVE_VFORK) || !defined(HAVE_FCNTL)
+#if !defined(HAVE_PIPE) || !defined(HAVE_FCNTL) || \
+    !(defined(HAVE_FORK) || defined(HAVE_VFORK))
 
 /*
  * On non-Posix systems, allow the program to build, but choke if
@@ -177,6 +178,12 @@ restart_read:
 		state->child_in_buf_avail = ret;
 	}
 
+	if (state->child_stdin == -1) {
+		fcntl(state->child_stdout, F_SETFL, 0);
+		__archive_check_child(state->child_stdin, state->child_stdout);
+		goto restart_read;
+	}
+
 	do {
 		ret = write(state->child_stdin, state->child_in_buf,
 		    state->child_in_buf_avail);
@@ -191,7 +198,7 @@ restart_read:
 		goto restart_read;
 	} else if (ret == 0 || (ret == -1 && errno == EPIPE)) {
 		close(state->child_stdin);
-		state->child_stdout = -1;
+		state->child_stdin = -1;
 		fcntl(state->child_stdout, F_SETFL, 0);
 		goto restart_read;
 	} else {
diff --git a/lib/libarchive/archive_write_set_compression_program.c b/lib/libarchive/archive_write_set_compression_program.c
index b910ef6..3cd5c93 100644
--- a/lib/libarchive/archive_write_set_compression_program.c
+++ b/lib/libarchive/archive_write_set_compression_program.c
@@ -28,7 +28,9 @@
 __FBSDID("$FreeBSD$");
 
 /* This capability is only available on POSIX systems. */
-#if !defined(HAVE_PIPE) || !defined(HAVE_VFORK) || !defined(HAVE_FCNTL)
+#if !defined(HAVE_PIPE) || !defined(HAVE_FCNTL) || \
+    !(defined(HAVE_FORK) || defined(HAVE_VFORK))
+#include "archive.h"
 
 /*
  * On non-Posix systems, allow the program to build, but choke if
@@ -180,6 +182,12 @@ restart_write:
 	if (ret == -1 && errno != EAGAIN)
 		return (-1);
 
+	if (state->child_stdout == -1) {
+		fcntl(state->child_stdin, F_SETFL, 0);
+		__archive_check_child(state->child_stdin, state->child_stdout);
+		goto restart_write;
+	}
+
 	do {
 		ret = read(state->child_stdout,
 		    state->child_buf + state->child_buf_avail,
diff --git a/lib/libarchive/filter_fork.c b/lib/libarchive/filter_fork.c
index dde6114..caf8c31 100644
--- a/lib/libarchive/filter_fork.c
+++ b/lib/libarchive/filter_fork.c
@@ -26,7 +26,8 @@
 #include "archive_platform.h"
 
 /* This capability is only available on POSIX systems. */
-#if defined(HAVE_PIPE) && defined(HAVE_VFORK) && defined(HAVE_FCNTL)
+#if defined(HAVE_PIPE) && defined(HAVE_FCNTL) && \
+    (defined(HAVE_FORK) || defined(HAVE_VFORK))
 
 __FBSDID("$FreeBSD$");
 
@@ -75,7 +76,11 @@ __archive_create_child(const char *path, int *child_stdin, int *child_stdout)
 		stdout_pipe[1] = tmp;
 	}
 
+#if HAVE_VFORK
 	switch ((child = vfork())) {
+#else
+	switch ((child = fork())) {
+#endif
 	case -1:
 		goto stdout_opened;
 	case 0:
@@ -118,23 +123,35 @@ __archive_check_child(int in, int out)
 {
 #if defined(HAVE_POLL)
 	struct pollfd fds[2];
+	int idx;
 
-	fds[0].fd = in;
-	fds[0].events = POLLOUT;
-	fds[1].fd = out;
-	fds[1].events = POLLIN;
+	idx = 0;
+	if (in != -1) {
+		fds[idx].fd = in;
+		fds[idx].events = POLLOUT;
+		++idx;
+	}
+	if (out != -1) {
+		fds[idx].fd = out;
+		fds[idx].events = POLLIN;
+		++idx;
+	}
 
-	poll(fds, 2, -1); /* -1 == INFTIM, wait forever */
+	poll(fds, idx, -1); /* -1 == INFTIM, wait forever */
 #elif defined(HAVE_SELECT)
 	fd_set fds_in, fds_out, fds_error;
 
 	FD_ZERO(&fds_in);
-	FD_SET(out, &fds_in);
 	FD_ZERO(&fds_out);
-	FD_SET(in, &fds_out);
 	FD_ZERO(&fds_error);
-	FD_SET(in, &fds_error);
-	FD_SET(out, &fds_error);
+	if (out != -1) {
+		FD_SET(out, &fds_in);
+		FD_SET(out, &fds_error);
+	}
+	if (in != -1) {
+		FD_SET(in, &fds_out);
+		FD_SET(in, &fds_error);
+	}
 	select(in < out ? out + 1 : in + 1, &fds_in, &fds_out, &fds_error, NULL);
 #else
 	sleep(1);