diff options
| -rw-r--r-- | libbb/gz_open.c | 74 |
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)); |