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 2008-04-21 21:56:07 +00:00
parent a4a93fdf18
commit 5a07a1d255
3 changed files with 121 additions and 105 deletions

View File

@ -1,7 +1,7 @@
#
# Automatically generated make config: don't edit
# Busybox version: 1.10.0.svn
# Thu Mar 20 14:54:21 2008
# Busybox version: 1.11.0.svn
# Mon Apr 21 23:20:35 2008
#
CONFIG_HAVE_DOT_CONFIG=y
@ -100,6 +100,7 @@ CONFIG_FEATURE_AR_LONG_FILENAMES=y
CONFIG_BUNZIP2=y
CONFIG_BZIP2=y
CONFIG_CPIO=y
CONFIG_FEATURE_CPIO_O=y
CONFIG_DPKG=y
CONFIG_DPKG_DEB=y
CONFIG_FEATURE_DPKG_DEB_EXTRACT_ONLY=y
@ -485,6 +486,7 @@ CONFIG_LOSETUP=y
CONFIG_MDEV=y
CONFIG_FEATURE_MDEV_CONF=y
CONFIG_FEATURE_MDEV_RENAME=y
CONFIG_FEATURE_MDEV_RENAME_REGEXP=y
CONFIG_FEATURE_MDEV_EXEC=y
CONFIG_FEATURE_MDEV_LOAD_FIRMWARE=y
CONFIG_MKSWAP=y
@ -521,6 +523,7 @@ CONFIG_PIVOT_ROOT=y
CONFIG_RDATE=y
CONFIG_READPROFILE=y
CONFIG_RTCWAKE=y
CONFIG_SCRIPT=y
CONFIG_SETARCH=y
CONFIG_SWAPONOFF=y
CONFIG_SWITCH_ROOT=y
@ -559,6 +562,7 @@ CONFIG_DC=y
# CONFIG_FEATURE_DEVFS is not set
CONFIG_EJECT=y
CONFIG_FEATURE_EJECT_SCSI=y
CONFIG_FBSPLASH=y
CONFIG_LAST=y
CONFIG_LESS=y
CONFIG_FEATURE_LESS_MAXLINES=9999999
@ -577,6 +581,7 @@ CONFIG_FEATURE_HDPARM_HDIO_GETSET_DMA=y
CONFIG_MAKEDEVS=y
# CONFIG_FEATURE_MAKEDEVS_LEAF is not set
CONFIG_FEATURE_MAKEDEVS_TABLE=y
CONFIG_MAN=y
CONFIG_MICROCOM=y
CONFIG_MOUNTPOINT=y
CONFIG_MT=y
@ -584,9 +589,9 @@ CONFIG_RAIDAUTORUN=y
CONFIG_READAHEAD=y
CONFIG_RUNLEVEL=y
CONFIG_RX=y
CONFIG_SCRIPT=y
CONFIG_STRINGS=y
CONFIG_SETSID=y
CONFIG_STRINGS=y
CONFIG_SYMLINKS=y
CONFIG_TASKSET=y
CONFIG_FEATURE_TASKSET_FANCY=y
CONFIG_TIME=y
@ -603,6 +608,7 @@ CONFIG_ARP=y
CONFIG_ARPING=y
CONFIG_BRCTL=y
CONFIG_FEATURE_BRCTL_FANCY=y
CONFIG_FEATURE_BRCTL_SHOW=y
CONFIG_DNSD=y
CONFIG_ETHER_WAKE=y
CONFIG_FAKEIDENTD=y
@ -751,6 +757,7 @@ CONFIG_WATCH=y
# CONFIG_FEATURE_SH_IS_MSH is not set
CONFIG_FEATURE_SH_IS_NONE=y
# CONFIG_ASH is not set
# CONFIG_ASH_BASH_COMPAT is not set
# CONFIG_ASH_JOB_CONTROL is not set
# CONFIG_ASH_READ_NCHARS is not set
# CONFIG_ASH_READ_TIMEOUT is not set
@ -780,6 +787,7 @@ CONFIG_MSH=y
#
CONFIG_FEATURE_SH_EXTRA_QUIET=y
CONFIG_FEATURE_SH_STANDALONE=y
CONFIG_FEATURE_SH_NOFORK=y
CONFIG_CTTYHACK=y
#

View File

@ -22,11 +22,13 @@ int open_transformer(int src_fd,
#if BB_MMU
pid = fork();
if (pid == -1)
bb_perror_msg_and_die("can't fork");
#else
pid = vfork();
#endif
if (pid == -1)
bb_perror_msg_and_die("fork failed");
bb_perror_msg_and_die("can't vfork");
#endif
if (pid == 0) {
/* child process */
@ -49,7 +51,7 @@ int open_transformer(int src_fd,
argv[2] = (char*)"-";
argv[3] = NULL;
BB_EXECVP(transform_prog, argv);
bb_perror_msg_and_die("exec failed");
bb_perror_msg_and_die("can't exec %s", transform_prog);
}
#endif
/* notreached */

View File

@ -84,26 +84,26 @@ struct TarHeader { /* byte offset */
*/
typedef struct HardLinkInfo HardLinkInfo;
struct HardLinkInfo {
HardLinkInfo *next; /* Next entry in list */
dev_t dev; /* Device number */
ino_t ino; /* Inode number */
short linkCount; /* (Hard) Link Count */
char name[1]; /* Start of filename (must be last) */
HardLinkInfo *next; /* Next entry in list */
dev_t dev; /* Device number */
ino_t ino; /* Inode number */
short linkCount; /* (Hard) Link Count */
char name[1]; /* Start of filename (must be last) */
};
/* Some info to be carried along when creating a new tarball */
typedef struct TarBallInfo TarBallInfo;
struct TarBallInfo {
int tarFd; /* Open-for-write file descriptor
for the tarball */
struct stat statBuf; /* Stat info for the tarball, letting
us know the inode and device that the
tarball lives, so we can avoid trying
to include the tarball into itself */
int verboseFlag; /* Whether to print extra stuff or not */
const llist_t *excludeList; /* List of files to not include */
HardLinkInfo *hlInfoHead; /* Hard Link Tracking Information */
HardLinkInfo *hlInfo; /* Hard Link Info for the current file */
int tarFd; /* Open-for-write file descriptor
* for the tarball */
struct stat statBuf; /* Stat info for the tarball, letting
* us know the inode and device that the
* tarball lives, so we can avoid trying
* to include the tarball into itself */
int verboseFlag; /* Whether to print extra stuff or not */
const llist_t *excludeList; /* List of files to not include */
HardLinkInfo *hlInfoHead; /* Hard Link Tracking Information */
HardLinkInfo *hlInfo; /* Hard Link Info for the current file */
};
/* A nice enum with all the possible tar file content types */
@ -503,11 +503,87 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
return TRUE;
}
static int writeTarFile(const int tar_fd, const int verboseFlag,
const unsigned long dereferenceFlag, const llist_t *include,
const llist_t *exclude, const int gzip)
#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
/* Don't inline: vfork scares gcc and pessimizes code */
static void NOINLINE vfork_compressor(int tar_fd, int gzip)
{
pid_t gzipPid;
#if ENABLE_FEATURE_TAR_GZIP && ENABLE_FEATURE_TAR_BZIP2
const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
#elif ENABLE_FEATURE_TAR_GZIP
const char *zip_exec = "gzip";
#else /* only ENABLE_FEATURE_TAR_BZIP2 */
const char *zip_exec = "bzip2";
#endif
// 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;
#if WAIT_FOR_CHILD
struct fd_pair gzipStatusPipe;
xpiped_pair(gzipStatusPipe);
#endif
xpiped_pair(gzipDataPipe);
signal(SIGPIPE, SIG_IGN); /* we only want EPIPE on errors */
#if defined(__GNUC__) && __GNUC__
/* Avoid vfork clobbering */
(void) &zip_exec;
#endif
gzipPid = vfork();
if (gzipPid < 0)
bb_perror_msg_and_die("can't vfork");
if (gzipPid == 0) {
/* child */
/* NB: close _first_, then move fds! */
close(gzipDataPipe.wr);
#if WAIT_FOR_CHILD
close(gzipStatusPipe.rd);
/* gzipStatusPipe.wr will close only on exec -
* parent waits for this close to happen */
fcntl(gzipStatusPipe.wr, F_SETFD, FD_CLOEXEC);
#endif
xmove_fd(gzipDataPipe.rd, 0);
xmove_fd(tar_fd, 1);
/* exec gzip/bzip2 program/applet */
BB_EXECLP(zip_exec, zip_exec, "-f", NULL);
vfork_exec_errno = errno;
_exit(1);
}
/* parent */
xmove_fd(gzipDataPipe.wr, tar_fd);
close(gzipDataPipe.rd);
#if WAIT_FOR_CHILD
close(gzipStatusPipe.wr);
while (1) {
char buf;
int n;
/* Wait until child execs (or fails to) */
n = full_read(gzipStatusPipe.rd, &buf, 1);
if (n < 0 /* && errno == EAGAIN */)
continue; /* try it again */
}
close(gzipStatusPipe.rd);
#endif
if (vfork_exec_errno) {
errno = vfork_exec_errno;
bb_perror_msg_and_die("cannot exec %s", zip_exec);
}
}
#endif /* ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2 */
/* gcc 4.2.1 inlines it, making code bigger */
static NOINLINE int writeTarFile(int tar_fd, int verboseFlag,
int dereferenceFlag, const llist_t *include,
const llist_t *exclude, int gzip)
{
pid_t gzipPid = 0;
int errorFlag = FALSE;
struct TarBallInfo tbInfo;
@ -523,80 +599,8 @@ 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
if (gzip) {
#if ENABLE_FEATURE_TAR_GZIP && ENABLE_FEATURE_TAR_BZIP2
const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
#elif ENABLE_FEATURE_TAR_GZIP
const char *zip_exec = "gzip";
#else /* only ENABLE_FEATURE_TAR_BZIP2 */
const char *zip_exec = "bzip2";
#endif
// 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 fd_pair gzipStatusPipe;
#endif
struct fd_pair gzipDataPipe;
xpiped_pair(gzipDataPipe);
#if WAIT_FOR_CHILD
xpiped_pair(gzipStatusPipe);
#endif
signal(SIGPIPE, SIG_IGN); /* we only want EPIPE on errors */
#if defined(__GNUC__) && __GNUC__
/* Avoid vfork clobbering */
(void) &include;
(void) &errorFlag;
(void) &zip_exec;
#endif
gzipPid = vfork();
if (gzipPid < 0)
bb_perror_msg_and_die("vfork gzip");
if (gzipPid == 0) {
/* child */
/* NB: close _first_, then move fds! */
close(gzipDataPipe.wr);
#if WAIT_FOR_CHILD
close(gzipStatusPipe.rd);
/* gzipStatusPipe.wr will close only on exec -
* parent waits for this close to happen */
fcntl(gzipStatusPipe.wr, F_SETFD, FD_CLOEXEC);
#endif
xmove_fd(gzipDataPipe.rd, 0);
xmove_fd(tbInfo.tarFd, 1);
/* exec gzip/bzip2 program/applet */
BB_EXECLP(zip_exec, zip_exec, "-f", NULL);
vfork_exec_errno = errno;
_exit(1);
}
/* parent */
xmove_fd(gzipDataPipe.wr, tbInfo.tarFd);
close(gzipDataPipe.rd);
#if WAIT_FOR_CHILD
close(gzipStatusPipe.wr);
while (1) {
char buf;
int n;
/* Wait until child execs (or fails to) */
n = full_read(gzipStatusPipe.rd, &buf, 1);
if (n < 0 /* && errno == EAGAIN */)
continue; /* try it again */
}
close(gzipStatusPipe.rd);
#endif
if (vfork_exec_errno) {
errno = vfork_exec_errno;
bb_perror_msg_and_die("cannot exec %s", zip_exec);
}
}
if (gzip)
vfork_compressor(tbInfo.tarFd, gzip);
#endif
tbInfo.excludeList = exclude;
@ -630,20 +634,22 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
if (errorFlag)
bb_error_msg("error exit delayed from previous errors");
if (gzipPid) {
#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
if (gzip) {
int status;
if (safe_waitpid(gzipPid, &status, 0) == -1)
if (safe_waitpid(-1, &status, 0) == -1)
bb_perror_msg("waitpid");
else if (!WIFEXITED(status) || WEXITSTATUS(status))
/* gzip was killed or has exited with nonzero! */
errorFlag = TRUE;
}
#endif
return errorFlag;
}
#else
int writeTarFile(const int tar_fd, const int verboseFlag,
const unsigned long dereferenceFlag, const llist_t *include,
const llist_t *exclude, const int gzip);
int writeTarFile(int tar_fd, int verboseFlag,
int dereferenceFlag, const llist_t *include,
const llist_t *exclude, int gzip);
#endif /* FEATURE_TAR_CREATE */
#if ENABLE_FEATURE_TAR_FROM