busybox/archival/libunarchive/open_transformer.c

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/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
#include "unarchive.h"
/* transformer(), more than meets the eye */
/*
* On MMU machine, the transform_prog and ... are stripped
* by a macro in include/unarchive.h. On NOMMU, transformer is stripped.
*/
int open_transformer(int src_fd,
USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd),
const char *transform_prog, ...)
{
int fd_pipe[2];
int pid;
xpipe(fd_pipe);
#if BB_MMU
pid = fork();
#else
pid = vfork();
#endif
if (pid == -1)
bb_perror_msg_and_die("fork failed");
if (pid == 0) {
#if !BB_MMU
va_list ap;
#endif
/* child process */
close(fd_pipe[0]); /* We don't wan't to read from the parent */
// FIXME: error check?
#if BB_MMU
transformer(src_fd, fd_pipe[1]);
if (ENABLE_FEATURE_CLEAN_UP) {
close(fd_pipe[1]); /* Send EOF */
close(src_fd);
}
exit(0);
#else
xmove_fd(src_fd, 0);
xmove_fd(fd_pipe[1], 1);
va_start(ap, transform_prog);
2007-09-09 16:50:55 +05:30
/* hoping that va_list -> char** on our CPU is working... */
BB_EXECVP(transform_prog, (void*)ap);
bb_perror_msg_and_die("exec failed");
#endif
/* notreached */
}
/* parent process */
close(fd_pipe[1]); /* Don't want to write to the child */
return fd_pipe[0];
}