45d68c374
Denys Vlasenko
2018-08-04
Subject
tar: make source code a bit more terse, no logic changes
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Commit Diff GitHub →
archival/tar.c+25 -32
| @@ -596,34 +596,30 @@ static int FAST_FUNC writeFileToTarball(const char *fileName, struct stat *statb | |
| /* Don't inline: vfork scares gcc and pessimizes code */ | |
| static void NOINLINE vfork_compressor(int tar_fd, const char *gzip) | |
| { | |
| - | pid_t gzipPid; |
| - | |
| // On Linux, vfork never unpauses parent early, although standard | |
| // allows for that. Do we want to waste bytes checking for it? | |
| # define WAIT_FOR_CHILD 0 | |
| volatile int vfork_exec_errno = 0; | |
| - | struct fd_pair gzipDataPipe; |
| + | struct fd_pair data; |
| # if WAIT_FOR_CHILD | |
| - | struct fd_pair gzipStatusPipe; |
| - | xpiped_pair(gzipStatusPipe); |
| + | struct fd_pair status; |
| + | xpiped_pair(status); |
| # endif | |
| - | xpiped_pair(gzipDataPipe); |
| + | xpiped_pair(data); |
| signal(SIGPIPE, SIG_IGN); /* we only want EPIPE on errors */ | |
| - | gzipPid = xvfork(); |
| - | |
| - | if (gzipPid == 0) { |
| + | if (xvfork() == 0) { |
| /* child */ | |
| /* NB: close _first_, then move fds! */ | |
| - | close(gzipDataPipe.wr); |
| + | close(data.wr); |
| # if WAIT_FOR_CHILD | |
| - | close(gzipStatusPipe.rd); |
| - | /* gzipStatusPipe.wr will close only on exec - |
| + | close(status.rd); |
| + | /* status.wr will close only on exec - |
| * parent waits for this close to happen */ | |
| - | fcntl(gzipStatusPipe.wr, F_SETFD, FD_CLOEXEC); |
| + | fcntl(status.wr, F_SETFD, FD_CLOEXEC); |
| # endif | |
| - | xmove_fd(gzipDataPipe.rd, 0); |
| + | xmove_fd(data.rd, 0); |
| xmove_fd(tar_fd, 1); | |
| /* exec gzip/bzip2 program/applet */ | |
| BB_EXECLP(gzip, gzip, "-f", (char *)0); | |
| @@ -632,20 +628,18 @@ static void NOINLINE vfork_compressor(int tar_fd, const char *gzip) | |
| } | |
| /* parent */ | |
| - | xmove_fd(gzipDataPipe.wr, tar_fd); |
| - | close(gzipDataPipe.rd); |
| + | xmove_fd(data.wr, tar_fd); |
| + | close(data.rd); |
| # if WAIT_FOR_CHILD | |
| - | close(gzipStatusPipe.wr); |
| + | close(status.wr); |
| while (1) { | |
| - | char buf; |
| - | int n; |
| - | |
| /* Wait until child execs (or fails to) */ | |
| - | n = full_read(gzipStatusPipe.rd, &buf, 1); |
| + | char buf; |
| + | int n = full_read(status.rd, &buf, 1); |
| if (n < 0 /* && errno == EAGAIN */) | |
| continue; /* try it again */ | |
| } | |
| - | close(gzipStatusPipe.rd); |
| + | close(status.rd); |
| # endif | |
| if (vfork_exec_errno) { | |
| errno = vfork_exec_errno; | |
| @@ -1155,17 +1149,16 @@ int tar_main(int argc UNUSED_PARAM, char **argv) | |
| if (LONE_DASH(tar_filename)) { | |
| tar_handle->src_fd = tar_fd; | |
| tar_handle->seek = seek_by_read; | |
| + | } else |
| + | if (ENABLE_FEATURE_TAR_AUTODETECT |
| + | && flags == O_RDONLY |
| + | && !(opt & OPT_ANY_COMPRESS) |
| + | ) { |
| + | tar_handle->src_fd = open_zipped(tar_filename, /*fail_if_not_compressed:*/ 0); |
| + | if (tar_handle->src_fd < 0) |
| + | bb_perror_msg_and_die("can't open '%s'", tar_filename); |
| } else { | |
| - | if (ENABLE_FEATURE_TAR_AUTODETECT |
| - | && flags == O_RDONLY |
| - | && !(opt & OPT_ANY_COMPRESS) |
| - | ) { |
| - | tar_handle->src_fd = open_zipped(tar_filename, /*fail_if_not_compressed:*/ 0); |
| - | if (tar_handle->src_fd < 0) |
| - | bb_perror_msg_and_die("can't open '%s'", tar_filename); |
| - | } else { |
| - | tar_handle->src_fd = xopen(tar_filename, flags); |
| - | } |
| + | tar_handle->src_fd = xopen(tar_filename, flags); |
| } | |
| } | |