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-rw-r--r--libbb/gz_open.c74
1 files changed, 64 insertions, 10 deletions
diff --git a/libbb/gz_open.c b/libbb/gz_open.c
index 3997e72..bdc7564 100644
--- a/libbb/gz_open.c
+++ b/libbb/gz_open.c
@@ -29,33 +29,69 @@
#include <unistd.h>
#include "libbb.h"
+static int gz_use_vfork;
+
FILE *
gz_open(FILE *compressed_file, int *pid)
{
int unzip_pipe[2];
+ off_t floc;
+ int cfile = -1;
+
+ gz_use_vfork = (getenv("OPKG_USE_VFORK") != NULL);
+
+ if (gz_use_vfork) {
+ /* Create a new file descriptor for the input stream
+ * (it *must* be associated with a file), and lseek()
+ * to the same position in that fd as the stream.
+ */
+ cfile = dup(fileno(compressed_file));
+ floc = ftello(compressed_file);
+ lseek(cfile, floc, SEEK_SET);
+ setenv("GZIP", "--quiet", 0);
+ }
if (pipe(unzip_pipe)!=0) {
perror_msg("pipe");
return(NULL);
}
- /* If we don't flush, we end up with two copies of anything pending,
- one from the parent, one from the child */
- fflush(stdout);
- fflush(stderr);
+ /* If we don't flush, we end up with two copies of anything pending,
+ one from the parent, one from the child */
+ fflush(stdout);
+ fflush(stderr);
- if ((*pid = fork()) == -1) {
+ if (gz_use_vfork) {
+ *pid = vfork();
+ } else {
+ *pid = fork();
+ }
+
+ if (*pid<0) {
perror_msg("fork");
return(NULL);
}
+
if (*pid==0) {
/* child process */
close(unzip_pipe[0]);
- unzip(compressed_file, fdopen(unzip_pipe[1], "w"));
- fflush(NULL);
- fclose(compressed_file);
- close(unzip_pipe[1]);
- _exit(EXIT_SUCCESS);
+ if (gz_use_vfork) {
+ dup2(unzip_pipe[1], 1);
+ dup2(cfile, 0);
+ execlp("gunzip","gunzip",NULL);
+ /* If we get here, we had a failure */
+ _exit(EXIT_FAILURE);
+ } else {
+ unzip(compressed_file, fdopen(unzip_pipe[1], "w"));
+ fflush(NULL);
+ fclose(compressed_file);
+ close(unzip_pipe[1]);
+ _exit(EXIT_SUCCESS);
+ }
+ }
+ /* Parent process is executing here */
+ if (gz_use_vfork) {
+ close(cfile);
}
close(unzip_pipe[1]);
return(fdopen(unzip_pipe[0], "r"));
@@ -67,11 +103,29 @@ gz_close(int gunzip_pid)
int status;
int ret;
+ if (gz_use_vfork) {
+ /* The gunzip process remains running in the background if we
+ * used the vfork()/exec() technique - so we have to kill it
+ * forcibly. There might be a better way to do this, but that
+ * affect a lot of other parts of opkg, and this works fine.
+ */
+ if (kill(gunzip_pid, SIGTERM) == -1) {
+ perror_msg("gz_close(): unable to kill gunzip pid.");
+ return -1;
+ }
+ }
+
+
if (waitpid(gunzip_pid, &status, 0) == -1) {
perror_msg("waitpid");
return -1;
}
+ if (gz_use_vfork) {
+ /* Bail out here if we used the vfork()/exec() technique. */
+ return 0;
+ }
+
if (WIFSIGNALED(status)) {
error_msg("Unzip process killed by signal %d.\n",
WTERMSIG(status));