tar: move vfork into separate function (smaller code)
open_transformer: more informative error messages function old new delta vfork_compressor - 210 +210 writeTarFile 547 299 -248 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 0/1 up/down: 210/-248) Total: -38 bytes
This commit is contained in:
Denis Vlasenko
@@ -22,11 +22,13 @@ int open_transformer(int src_fd,
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#if BB_MMU
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pid = fork();
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if (pid == -1)
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bb_perror_msg_and_die("can't fork");
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#else
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pid = vfork();
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#endif
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if (pid == -1)
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bb_perror_msg_and_die("fork failed");
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bb_perror_msg_and_die("can't vfork");
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#endif
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if (pid == 0) {
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/* child process */
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@@ -49,7 +51,7 @@ int open_transformer(int src_fd,
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argv[2] = (char*)"-";
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argv[3] = NULL;
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BB_EXECVP(transform_prog, argv);
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bb_perror_msg_and_die("exec failed");
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bb_perror_msg_and_die("can't exec %s", transform_prog);
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}
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#endif
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/* notreached */
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202
archival/tar.c
202
archival/tar.c
@@ -84,26 +84,26 @@ struct TarHeader { /* byte offset */
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*/
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typedef struct HardLinkInfo HardLinkInfo;
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struct HardLinkInfo {
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HardLinkInfo *next; /* Next entry in list */
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dev_t dev; /* Device number */
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ino_t ino; /* Inode number */
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short linkCount; /* (Hard) Link Count */
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char name[1]; /* Start of filename (must be last) */
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HardLinkInfo *next; /* Next entry in list */
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dev_t dev; /* Device number */
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ino_t ino; /* Inode number */
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short linkCount; /* (Hard) Link Count */
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char name[1]; /* Start of filename (must be last) */
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};
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/* Some info to be carried along when creating a new tarball */
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typedef struct TarBallInfo TarBallInfo;
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struct TarBallInfo {
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int tarFd; /* Open-for-write file descriptor
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for the tarball */
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struct stat statBuf; /* Stat info for the tarball, letting
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us know the inode and device that the
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tarball lives, so we can avoid trying
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to include the tarball into itself */
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int verboseFlag; /* Whether to print extra stuff or not */
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const llist_t *excludeList; /* List of files to not include */
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HardLinkInfo *hlInfoHead; /* Hard Link Tracking Information */
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HardLinkInfo *hlInfo; /* Hard Link Info for the current file */
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int tarFd; /* Open-for-write file descriptor
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* for the tarball */
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struct stat statBuf; /* Stat info for the tarball, letting
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* us know the inode and device that the
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* tarball lives, so we can avoid trying
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* to include the tarball into itself */
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int verboseFlag; /* Whether to print extra stuff or not */
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const llist_t *excludeList; /* List of files to not include */
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HardLinkInfo *hlInfoHead; /* Hard Link Tracking Information */
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HardLinkInfo *hlInfo; /* Hard Link Info for the current file */
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};
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/* A nice enum with all the possible tar file content types */
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@@ -503,11 +503,87 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
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return TRUE;
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}
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static int writeTarFile(const int tar_fd, const int verboseFlag,
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const unsigned long dereferenceFlag, const llist_t *include,
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const llist_t *exclude, const int gzip)
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#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
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/* Don't inline: vfork scares gcc and pessimizes code */
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static void NOINLINE vfork_compressor(int tar_fd, int gzip)
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{
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pid_t gzipPid;
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#if ENABLE_FEATURE_TAR_GZIP && ENABLE_FEATURE_TAR_BZIP2
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const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
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#elif ENABLE_FEATURE_TAR_GZIP
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const char *zip_exec = "gzip";
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#else /* only ENABLE_FEATURE_TAR_BZIP2 */
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const char *zip_exec = "bzip2";
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#endif
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// On Linux, vfork never unpauses parent early, although standard
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// allows for that. Do we want to waste bytes checking for it?
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#define WAIT_FOR_CHILD 0
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volatile int vfork_exec_errno = 0;
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struct fd_pair gzipDataPipe;
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#if WAIT_FOR_CHILD
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struct fd_pair gzipStatusPipe;
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xpiped_pair(gzipStatusPipe);
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#endif
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xpiped_pair(gzipDataPipe);
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signal(SIGPIPE, SIG_IGN); /* we only want EPIPE on errors */
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#if defined(__GNUC__) && __GNUC__
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/* Avoid vfork clobbering */
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(void) &zip_exec;
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#endif
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gzipPid = vfork();
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if (gzipPid < 0)
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bb_perror_msg_and_die("can't vfork");
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if (gzipPid == 0) {
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/* child */
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/* NB: close _first_, then move fds! */
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close(gzipDataPipe.wr);
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#if WAIT_FOR_CHILD
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close(gzipStatusPipe.rd);
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/* gzipStatusPipe.wr will close only on exec -
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* parent waits for this close to happen */
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fcntl(gzipStatusPipe.wr, F_SETFD, FD_CLOEXEC);
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#endif
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xmove_fd(gzipDataPipe.rd, 0);
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xmove_fd(tar_fd, 1);
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/* exec gzip/bzip2 program/applet */
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BB_EXECLP(zip_exec, zip_exec, "-f", NULL);
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vfork_exec_errno = errno;
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_exit(1);
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}
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/* parent */
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xmove_fd(gzipDataPipe.wr, tar_fd);
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close(gzipDataPipe.rd);
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#if WAIT_FOR_CHILD
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close(gzipStatusPipe.wr);
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while (1) {
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char buf;
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int n;
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/* Wait until child execs (or fails to) */
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n = full_read(gzipStatusPipe.rd, &buf, 1);
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if (n < 0 /* && errno == EAGAIN */)
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continue; /* try it again */
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}
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close(gzipStatusPipe.rd);
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#endif
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if (vfork_exec_errno) {
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errno = vfork_exec_errno;
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bb_perror_msg_and_die("cannot exec %s", zip_exec);
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}
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}
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#endif /* ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2 */
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/* gcc 4.2.1 inlines it, making code bigger */
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static NOINLINE int writeTarFile(int tar_fd, int verboseFlag,
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int dereferenceFlag, const llist_t *include,
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const llist_t *exclude, int gzip)
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{
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pid_t gzipPid = 0;
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int errorFlag = FALSE;
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struct TarBallInfo tbInfo;
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@@ -523,80 +599,8 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
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bb_perror_msg_and_die("cannot stat tar file");
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#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
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if (gzip) {
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#if ENABLE_FEATURE_TAR_GZIP && ENABLE_FEATURE_TAR_BZIP2
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const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
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#elif ENABLE_FEATURE_TAR_GZIP
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const char *zip_exec = "gzip";
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#else /* only ENABLE_FEATURE_TAR_BZIP2 */
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const char *zip_exec = "bzip2";
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#endif
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// On Linux, vfork never unpauses parent early, although standard
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// allows for that. Do we want to waste bytes checking for it?
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#define WAIT_FOR_CHILD 0
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volatile int vfork_exec_errno = 0;
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#if WAIT_FOR_CHILD
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struct fd_pair gzipStatusPipe;
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#endif
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struct fd_pair gzipDataPipe;
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xpiped_pair(gzipDataPipe);
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#if WAIT_FOR_CHILD
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xpiped_pair(gzipStatusPipe);
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#endif
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signal(SIGPIPE, SIG_IGN); /* we only want EPIPE on errors */
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#if defined(__GNUC__) && __GNUC__
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/* Avoid vfork clobbering */
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(void) &include;
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(void) &errorFlag;
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(void) &zip_exec;
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#endif
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gzipPid = vfork();
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if (gzipPid < 0)
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bb_perror_msg_and_die("vfork gzip");
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if (gzipPid == 0) {
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/* child */
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/* NB: close _first_, then move fds! */
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close(gzipDataPipe.wr);
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#if WAIT_FOR_CHILD
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close(gzipStatusPipe.rd);
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/* gzipStatusPipe.wr will close only on exec -
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* parent waits for this close to happen */
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fcntl(gzipStatusPipe.wr, F_SETFD, FD_CLOEXEC);
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#endif
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xmove_fd(gzipDataPipe.rd, 0);
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xmove_fd(tbInfo.tarFd, 1);
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/* exec gzip/bzip2 program/applet */
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BB_EXECLP(zip_exec, zip_exec, "-f", NULL);
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vfork_exec_errno = errno;
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_exit(1);
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}
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/* parent */
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xmove_fd(gzipDataPipe.wr, tbInfo.tarFd);
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close(gzipDataPipe.rd);
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#if WAIT_FOR_CHILD
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close(gzipStatusPipe.wr);
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while (1) {
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char buf;
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int n;
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/* Wait until child execs (or fails to) */
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n = full_read(gzipStatusPipe.rd, &buf, 1);
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if (n < 0 /* && errno == EAGAIN */)
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continue; /* try it again */
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}
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close(gzipStatusPipe.rd);
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#endif
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if (vfork_exec_errno) {
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errno = vfork_exec_errno;
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bb_perror_msg_and_die("cannot exec %s", zip_exec);
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}
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}
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if (gzip)
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vfork_compressor(tbInfo.tarFd, gzip);
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#endif
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tbInfo.excludeList = exclude;
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@@ -630,20 +634,22 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
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if (errorFlag)
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bb_error_msg("error exit delayed from previous errors");
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if (gzipPid) {
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#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
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if (gzip) {
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int status;
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if (safe_waitpid(gzipPid, &status, 0) == -1)
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if (safe_waitpid(-1, &status, 0) == -1)
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bb_perror_msg("waitpid");
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else if (!WIFEXITED(status) || WEXITSTATUS(status))
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/* gzip was killed or has exited with nonzero! */
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errorFlag = TRUE;
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}
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#endif
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return errorFlag;
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}
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#else
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int writeTarFile(const int tar_fd, const int verboseFlag,
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const unsigned long dereferenceFlag, const llist_t *include,
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const llist_t *exclude, const int gzip);
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int writeTarFile(int tar_fd, int verboseFlag,
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int dereferenceFlag, const llist_t *include,
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const llist_t *exclude, int gzip);
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#endif /* FEATURE_TAR_CREATE */
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#if ENABLE_FEATURE_TAR_FROM
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