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authorGravatar Denis Vlasenko <vda.linux@googlemail.com>2007-09-04 19:33:22 +0000
committerGravatar Denis Vlasenko <vda.linux@googlemail.com>2007-09-04 19:33:22 +0000
commit7e0fbf9c26350a819661241bc925cb88f26bb992 (patch)
tree827570e004a3af086963154f0379b662fd0a3ea5
parentf0000653e90fdbddcd49adb69909ab60c88feda5 (diff)
downloadbusybox-7e0fbf9c26350a819661241bc925cb88f26bb992.tar.gz
busybox-7e0fbf9c26350a819661241bc925cb88f26bb992.tar.bz2
tar: conditionally don't wait for vforked child to exec, as it always
works right on Linux, and anyway mayresult only on less-than-clear error message only, it will not cause tar to misbehave. function old new delta open_transformer 98 80 -18 writeTarFile 714 547 -167 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-185) Total: -185 bytes text data bss dec hex filename 770651 1051 10764 782466 bf082 busybox_old 770463 1051 10764 782278 befc6 busybox_unstripped
-rw-r--r--archival/libunarchive/open_transformer.c6
-rw-r--r--archival/tar.c82
-rw-r--r--include/libbb.h3
3 files changed, 54 insertions, 37 deletions
diff --git a/archival/libunarchive/open_transformer.c b/archival/libunarchive/open_transformer.c
index 0ee080621..93f01be6f 100644
--- a/archival/libunarchive/open_transformer.c
+++ b/archival/libunarchive/open_transformer.c
@@ -25,8 +25,10 @@ int open_transformer(int src_fd,
close(fd_pipe[0]); /* We don't wan't to read from the parent */
// FIXME: error check?
transformer(src_fd, fd_pipe[1]);
- close(fd_pipe[1]); /* Send EOF */
- close(src_fd);
+ if (ENABLE_FEATURE_CLEAN_UP) {
+ close(fd_pipe[1]); /* Send EOF */
+ close(src_fd);
+ }
exit(0);
/* notreached */
}
diff --git a/archival/tar.c b/archival/tar.c
index 9bf9058d8..f0d397114 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -106,7 +106,7 @@ enum TarFileType {
typedef enum TarFileType TarFileType;
/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
-static void addHardLinkInfo(HardLinkInfo ** hlInfoHeadPtr,
+static void addHardLinkInfo(HardLinkInfo **hlInfoHeadPtr,
struct stat *statbuf,
const char *fileName)
{
@@ -122,7 +122,7 @@ static void addHardLinkInfo(HardLinkInfo ** hlInfoHeadPtr,
strcpy(hlInfo->name, fileName);
}
-static void freeHardLinkInfo(HardLinkInfo ** hlInfoHeadPtr)
+static void freeHardLinkInfo(HardLinkInfo **hlInfoHeadPtr)
{
HardLinkInfo *hlInfo;
HardLinkInfo *hlInfoNext;
@@ -139,7 +139,7 @@ static void freeHardLinkInfo(HardLinkInfo ** hlInfoHeadPtr)
}
/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
-static HardLinkInfo *findHardLinkInfo(HardLinkInfo * hlInfo, struct stat *statbuf)
+static HardLinkInfo *findHardLinkInfo(HardLinkInfo *hlInfo, struct stat *statbuf)
{
while (hlInfo) {
if ((statbuf->st_ino == hlInfo->ino) && (statbuf->st_dev == hlInfo->dev))
@@ -504,13 +504,21 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
bb_perror_msg_and_die("cannot stat tar file");
if ((ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2) && gzip) {
- int gzipDataPipe[2] = { -1, -1 };
- int gzipStatusPipe[2] = { -1, -1 };
+// 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;
+#if WAIT_FOR_CHILD
+ struct { int rd; int wr; } gzipStatusPipe;
+#endif
+ struct { int rd; int wr; } gzipDataPipe;
const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
- xpipe(gzipDataPipe);
- xpipe(gzipStatusPipe);
+ xpipe(&gzipDataPipe.rd);
+#if WAIT_FOR_CHILD
+ xpipe(&gzipStatusPipe.rd);
+#endif
signal(SIGPIPE, SIG_IGN); /* we only want EPIPE on errors */
@@ -522,41 +530,45 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
#endif
gzipPid = vfork();
+ if (gzipPid < 0)
+ bb_perror_msg_and_die("vfork gzip");
if (gzipPid == 0) {
- dup2(gzipDataPipe[0], 0);
- close(gzipDataPipe[1]);
-
- dup2(tbInfo.tarFd, 1);
-
- close(gzipStatusPipe[0]);
- fcntl(gzipStatusPipe[1], F_SETFD, FD_CLOEXEC); /* close on exec shows success */
-
+ /* child */
+ xmove_fd(tbInfo.tarFd, 1);
+ xmove_fd(gzipDataPipe.rd, 0);
+ close(gzipDataPipe.wr);
+#if WAIT_FOR_CHILD
+ close(gzipStatusPipe.rd);
+ fcntl(gzipStatusPipe.wr, F_SETFD, FD_CLOEXEC);
+#endif
+ /* exec gzip/bzip2 program/applet */
BB_EXECLP(zip_exec, zip_exec, "-f", NULL);
vfork_exec_errno = errno;
+ _exit(1);
+ }
- close(gzipStatusPipe[1]);
- exit(-1);
- } else if (gzipPid > 0) {
- close(gzipDataPipe[0]);
- close(gzipStatusPipe[1]);
-
- while (1) {
- char buf;
-
- int n = full_read(gzipStatusPipe[0], &buf, 1);
+ /* parent */
+ xmove_fd(gzipDataPipe.wr, tbInfo.tarFd);
+ close(gzipDataPipe.rd);
+#if WAIT_FOR_CHILD
+ close(gzipStatusPipe.wr);
+ while (1) {
+ char buf;
+ int n;
- if (n == 0 && vfork_exec_errno != 0) {
- errno = vfork_exec_errno;
- bb_perror_msg_and_die("cannot exec %s", zip_exec);
- } else if ((n < 0) && (errno == EAGAIN || errno == EINTR))
- continue; /* try it again */
- break;
- }
- close(gzipStatusPipe[0]);
+ /* Wait until child execs (or fails to) */
+ n = full_read(gzipStatusPipe.rd, &buf, 1);
+ if ((n < 0) && (/*errno == EAGAIN ||*/ errno == EINTR))
+ continue; /* try it again */
- tbInfo.tarFd = gzipDataPipe[1];
- } else bb_perror_msg_and_die("vfork gzip");
+ }
+ close(gzipStatusPipe.rd);
+#endif
+ if (vfork_exec_errno) {
+ errno = vfork_exec_errno;
+ bb_perror_msg_and_die("cannot exec %s", zip_exec);
+ }
}
tbInfo.excludeList = exclude;
diff --git a/include/libbb.h b/include/libbb.h
index 6c6b4863c..cf00b5250 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -512,6 +512,9 @@ int execable_file(const char *name);
char *find_execable(const char *filename);
int exists_execable(const char *filename);
+/* BB_EXECxx always execs (it's not doing NOFORK/NOEXEC stuff),
+ * but it may exec busybox and call applet instead of searching PATH.
+ */
#if ENABLE_FEATURE_PREFER_APPLETS
int bb_execvp(const char *file, char *const argv[]);
#define BB_EXECVP(prog,cmd) bb_execvp(prog,cmd)