Send error messages from pre-xfer exec script to the user.

diff --git a/clientserver.c b/clientserver.c
index 8b6b896..8fedbe6 100644 (file)
--- a/clientserver.c
+++ b/clientserver.c
@@ -348,36 +348,51 @@ int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char
        return 0;
 }
 
-static char *finish_pre_exec(pid_t pid, int fd, char *request,
+static char *finish_pre_exec(pid_t pid, int write_fd, int read_fd, char *request,
                             char **early_argv, char **argv)
 {
-       int j = 0, status = -1;
+       char buf[BIGPATHBUFLEN], *bp;
+       int j = 0, status = -1, msglen = sizeof buf - 1;
 
        if (!request)
                request = "(NONE)";
 
-       write_buf(fd, request, strlen(request)+1);
+       write_buf(write_fd, request, strlen(request)+1);
        if (early_argv) {
                for ( ; *early_argv; early_argv++)
-                       write_buf(fd, *early_argv, strlen(*early_argv)+1);
+                       write_buf(write_fd, *early_argv, strlen(*early_argv)+1);
                j = 1; /* Skip arg0 name in argv. */
        }
        for ( ; argv[j]; j++) {
-               write_buf(fd, argv[j], strlen(argv[j])+1);
+               write_buf(write_fd, argv[j], strlen(argv[j])+1);
                if (argv[j][0] == '.' && argv[j][1] == '\0')
                        break;
        }
-       write_byte(fd, 0);
+       write_byte(write_fd, 0);
+
+       close(write_fd);
+
+       /* Read the stdout from the pre-xfer exec program.  This it is only
+        * displayed to the user if the script also returns an error status. */
+       for (bp = buf; msglen > 0 && (j = read(read_fd, bp, msglen)) > 0; msglen -= j) {
+               bp += j;
+               if (j > 1 && bp[-1] == '\n' && bp[-2] == '\r') {
+                       bp--;
+                       j--;
+                       bp[-1] = '\n';
+               }
+       }
+       *bp = '\0';
 
-       close(fd);
+       close(read_fd);
 
        if (wait_process(pid, &status, 0) < 0
         || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
                char *e;
-               if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n",
+               if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n%s",
                             status, status < 0 ? ": " : "",
-                            status < 0 ? strerror(errno) : "") < 0)
-                       out_of_memory("finish_pre_exec");
+                            status < 0 ? strerror(errno) : "", buf) < 0)
+                       return "out_of_memory in finish_pre_exec\n";
                return e;
        }
        return NULL;
@@ -494,7 +509,7 @@ static int rsync_module(int f_in, int f_out, int i, const char *addr, const char
        char *p, *err_msg = NULL;
        char *name = lp_name(i);
        int use_chroot = lp_use_chroot(i);
-       int ret, pre_exec_fd = -1;
+       int ret, pre_exec_arg_fd = -1, pre_exec_error_fd = -1;
        int save_munge_symlinks;
        pid_t pre_exec_pid = 0;
        char *request = NULL;
@@ -708,9 +723,9 @@ static int rsync_module(int f_in, int f_out, int i, const char *addr, const char
                 * command, though it first waits for the parent process to
                 * send us the user's request via a pipe. */
                if (*lp_prexfer_exec(i)) {
-                       int fds[2];
+                       int arg_fds[2], error_fds[2];
                        set_env_num("RSYNC_PID", (long)getpid());
-                       if (pipe(fds) < 0 || (pre_exec_pid = fork()) < 0) {
+                       if (pipe(arg_fds) < 0 || pipe(error_fds) < 0 || (pre_exec_pid = fork()) < 0) {
                                rsyserr(FLOG, errno, "pre-xfer exec preparation failed");
                                io_printf(f_out, "@ERROR: pre-xfer exec preparation failed\n");
                                return -1;
@@ -718,14 +733,18 @@ static int rsync_module(int f_in, int f_out, int i, const char *addr, const char
                        if (pre_exec_pid == 0) {
                                char buf[BIGPATHBUFLEN];
                                int j, len;
-                               close(fds[1]);
-                               set_blocking(fds[0]);
-                               len = read_arg_from_pipe(fds[0], buf, BIGPATHBUFLEN);
+                               close(arg_fds[1]);
+                               close(error_fds[0]);
+                               pre_exec_arg_fd = arg_fds[0];
+                               pre_exec_error_fd = error_fds[1];
+                               set_blocking(pre_exec_arg_fd);
+                               set_blocking(pre_exec_error_fd);
+                               len = read_arg_from_pipe(pre_exec_arg_fd, buf, BIGPATHBUFLEN);
                                if (len <= 0)
                                        _exit(1);
                                set_env_str("RSYNC_REQUEST", buf);
                                for (j = 0; ; j++) {
-                                       len = read_arg_from_pipe(fds[0], buf,
+                                       len = read_arg_from_pipe(pre_exec_arg_fd, buf,
                                                                 BIGPATHBUFLEN);
                                        if (len <= 0) {
                                                if (!len)
@@ -735,17 +754,21 @@ static int rsync_module(int f_in, int f_out, int i, const char *addr, const char
                                        if (asprintf(&p, "RSYNC_ARG%d=%s", j, buf) > 0)
                                                putenv(p);
                                }
-                               close(fds[0]);
+                               close(pre_exec_arg_fd);
                                close(STDIN_FILENO);
-                               close(STDOUT_FILENO);
+                               dup2(pre_exec_error_fd, STDOUT_FILENO);
+                               close(pre_exec_error_fd);
                                status = system(lp_prexfer_exec(i));
                                if (!WIFEXITED(status))
                                        _exit(1);
                                _exit(WEXITSTATUS(status));
                        }
-                       close(fds[0]);
-                       set_blocking(fds[1]);
-                       pre_exec_fd = fds[1];
+                       close(arg_fds[0]);
+                       close(error_fds[1]);
+                       pre_exec_arg_fd = arg_fds[1];
+                       pre_exec_error_fd = error_fds[0];
+                       set_blocking(pre_exec_arg_fd);
+                       set_blocking(pre_exec_error_fd);
                }
        }
 #endif
@@ -859,8 +882,8 @@ static int rsync_module(int f_in, int f_out, int i, const char *addr, const char
        munge_symlinks = save_munge_symlinks; /* The client mustn't control this. */
 
        if (pre_exec_pid) {
-               err_msg = finish_pre_exec(pre_exec_pid, pre_exec_fd, request,
-                                         orig_early_argv, orig_argv);
+               err_msg = finish_pre_exec(pre_exec_pid, pre_exec_arg_fd, pre_exec_error_fd,
+                                         request, orig_early_argv, orig_argv);
        }
 
        if (orig_early_argv)
@@ -931,9 +954,15 @@ static int rsync_module(int f_in, int f_out, int i, const char *addr, const char
        }
 
        if (!ret || err_msg) {
-               if (err_msg)
-                       rwrite(FERROR, err_msg, strlen(err_msg), 0);
-               else
+               if (err_msg) {
+                       while ((p = strchr(err_msg, '\n')) != NULL) {
+                               int len = p - err_msg + 1;
+                               rwrite(FERROR, err_msg, len, 0);
+                               err_msg += len;
+                       }
+                       if (*err_msg)
+                               rprintf(FERROR, "%s\n", err_msg);
+               } else
                        option_error();
                msleep(400);
                exit_cleanup(RERR_UNSUPPORTED);

diff --git a/rsyncd.conf.yo b/rsyncd.conf.yo
index 35d269f..240c63a 100644 (file)
--- a/rsyncd.conf.yo
+++ b/rsyncd.conf.yo
@@ -712,7 +712,12 @@ the sender.
 
 dit(bf(pre-xfer exec), bf(post-xfer exec)) You may specify a command to be run
 before and/or after the transfer.  If the bf(pre-xfer exec) command fails, the
-transfer is aborted before it begins.
+transfer is aborted before it begins.  Any output from the script on stdout (up
+to several KB) will be displayed to the user when aborting, but is NOT
+displayed if the script returns success.  Any output from the script on stderr
+goes to the daemon's stderr, which is typically discarded (though see
+--no-detatch option for a way to see the stderr output, which can assist with
+debugging).
 
 The following environment variables will be set, though some are
 specific to the pre-xfer or the post-xfer environment: