tar: report error if child dies while writing out the end of tarball

(e.g. out of disk space).

1 files changed, 39 insertions, 8 deletions

diff --git a/archival/tar.c b/archival/tar.c
index ba7cb0f8c..7465e881b 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -504,7 +504,6 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
                 volatile int vfork_exec_errno = 0;
                 char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
 
-
                 if (pipe(gzipDataPipe) < 0 || pipe(gzipStatusPipe) < 0)
                         bb_perror_msg_and_die("pipe");
 
@@ -585,10 +584,15 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
         if (errorFlag)
                 bb_error_msg("error exit delayed from previous errors");
 
-        if (gzipPid && waitpid(gzipPid, NULL, 0) == -1)
-                bb_error_msg("waitpid failed");
-
-        return !errorFlag;
+        if (gzipPid) {
+                int status;
+                if (waitpid(gzipPid, &status, 0) == -1)
+                        bb_perror_msg("waitpid");
+                else if (!WIFEXITED(status) || WEXITSTATUS(status))
+                        /* gzip was killed or has exited with nonzero! */
+                        errorFlag = TRUE;
+        }
+        return errorFlag;
 }
 #else
 int writeTarFile(const int tar_fd, const int verboseFlag,
@@ -650,6 +654,29 @@ static char get_header_tar_Z(archive_handle_t *archive_handle)
 #define get_header_tar_Z        0
 #endif
 
+#ifdef CHECK_FOR_CHILD_EXITCODE
+/* Looks like it isn't needed - tar detects malformed (truncated)
+ * archive if e.g. bunzip2 fails */
+static int child_error;
+
+static void handle_SIGCHLD(int status)
+{
+        /* Actually, 'status' is a signo. We reuse it for other needs */
+
+        /* Wait for any child without blocking */
+        if (waitpid(-1, &status, WNOHANG) < 0)
+                /* wait failed?! I'm confused... */
+                return;
+
+        if (WIFEXITED(status) && WEXITSTATUS(status)==0)
+                /* child exited with 0 */
+                return;
+        /* Cannot happen? 
+        if(!WIFSIGNALED(status) && !WIFEXITED(status)) return; */
+        child_error = 1;
+}
+#endif
+
 enum {
         OPTBIT_KEEP_OLD = 7,
         USE_FEATURE_TAR_CREATE(  OPTBIT_CREATE      ,)
@@ -862,6 +889,11 @@ int tar_main(int argc, char **argv)
         if (base_dir)
                 xchdir(base_dir);
 
+#ifdef CHECK_FOR_CHILD_EXITCODE
+        /* We need to know whether child (gzip/bzip/etc) exits abnormally */
+        signal(SIGCHLD, handle_SIGCHLD);
+#endif
+
         /* create an archive */
         if (opt & OPT_CREATE) {
                 int zipMode = 0;
@@ -869,11 +901,10 @@ int tar_main(int argc, char **argv)
                         zipMode = 1;
                 if (ENABLE_FEATURE_TAR_BZIP2 && get_header_ptr == get_header_tar_bz2)
                         zipMode = 2;
-                writeTarFile(tar_handle->src_fd, verboseFlag, opt & OPT_DEREFERENCE,
+                /* NB: writeTarFile() closes tar_handle->src_fd */
+                return writeTarFile(tar_handle->src_fd, verboseFlag, opt & OPT_DEREFERENCE,
                                 tar_handle->accept,
                                 tar_handle->reject, zipMode);
-                /* NB: writeTarFile() closes tar_handle->src_fd */
-                return EXIT_SUCCESS;
         }
 
         while (get_header_ptr(tar_handle) == EXIT_SUCCESS)