1 files changed, 150 insertions, 0 deletions
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 7df2d72..9b1bdf1 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -76,6 +76,156 @@ static void ga_wait_child(pid_t pid, int *status, Error **errp)
     g_assert(rpid == pid);
 }
 
+static ssize_t ga_pipe_read_str(int fd[2], char **str)
+{
+    ssize_t n, len = 0;
+    char buf[1024];
+
+    close(fd[1]);
+    fd[1] = -1;
+    while ((n = read(fd[0], buf, sizeof(buf))) != 0) {
+        if (n < 0) {
+            if (errno == EINTR) {
+                continue;
+            } else {
+                len = -errno;
+                break;
+            }
+        }
+        *str = g_realloc(*str, len + n + 1);
+        memcpy(*str + len, buf, n);
+        len += n;
+        *str[len] = '\0';
+    }
+    close(fd[0]);
+    fd[0] = -1;
+
+    return len;
+}
+
+/*
+ * Helper to run command with input/output redirection,
+ * sending string to stdin and taking error message from
+ * stdout/err.
+ */
+G_GNUC_UNUSED
+static int ga_run_command(const char *argv[], const char *in_str,
+                          const char *action, Error **errp)
+{
+    pid_t pid;
+    int status;
+    int retcode = -1;
+    int infd[2] = { -1, -1 };
+    int outfd[2] = { -1, -1 };
+    char *str = NULL;
+    ssize_t len = 0;
+
+    if ((in_str && !g_unix_open_pipe(infd, FD_CLOEXEC, NULL)) ||
+        !g_unix_open_pipe(outfd, FD_CLOEXEC, NULL)) {
+        error_setg(errp, "cannot create pipe FDs");
+        goto out;
+    }
+
+    pid = fork();
+    if (pid == 0) {
+        char *cherr = NULL;
+
+        setsid();
+
+        if (in_str) {
+            /* Redirect stdin to infd. */
+            close(infd[1]);
+            dup2(infd[0], 0);
+            close(infd[0]);
+        } else {
+            reopen_fd_to_null(0);
+        }
+
+        /* Redirect stdout/stderr to outfd. */
+        close(outfd[0]);
+        dup2(outfd[1], 1);
+        dup2(outfd[1], 2);
+        close(outfd[1]);
+
+        execvp(argv[0], (char *const *)argv);
+
+        /* Write the cause of failed exec to pipe for the parent to read it. */
+        cherr = g_strdup_printf("failed to exec '%s'", argv[0]);
+        perror(cherr);
+        g_free(cherr);
+        _exit(EXIT_FAILURE);
+    } else if (pid < 0) {
+        error_setg_errno(errp, errno, "failed to create child process");
+        goto out;
+    }
+
+    if (in_str) {
+        close(infd[0]);
+        infd[0] = -1;
+        if (qemu_write_full(infd[1], in_str, strlen(in_str)) !=
+                strlen(in_str)) {
+            error_setg_errno(errp, errno, "%s: cannot write to stdin pipe",
+                             action);
+            goto out;
+        }
+        close(infd[1]);
+        infd[1] = -1;
+    }
+
+    len = ga_pipe_read_str(outfd, &str);
+    if (len < 0) {
+        error_setg_errno(errp, -len, "%s: cannot read from stdout/stderr pipe",
+                         action);
+        goto out;
+    }
+
+    ga_wait_child(pid, &status, errp);
+    if (*errp) {
+        goto out;
+    }
+
+    if (!WIFEXITED(status)) {
+        if (len) {
+            error_setg(errp, "child process has terminated abnormally: %s",
+                       str);
+        } else {
+            error_setg(errp, "child process has terminated abnormally");
+        }
+        goto out;
+    }
+
+    retcode = WEXITSTATUS(status);
+
+    if (WEXITSTATUS(status)) {
+        if (len) {
+            error_setg(errp, "child process has failed to %s: %s",
+                       action, str);
+        } else {
+            error_setg(errp, "child process has failed to %s: exit status %d",
+                       action, WEXITSTATUS(status));
+        }
+        goto out;
+    }
+
+out:
+    g_free(str);
+
+    if (infd[0] != -1) {
+        close(infd[0]);
+    }
+    if (infd[1] != -1) {
+        close(infd[1]);
+    }
+    if (outfd[0] != -1) {
+        close(outfd[0]);
+    }
+    if (outfd[1] != -1) {
+        close(outfd[1]);
+    }
+
+    return retcode;
+}
+
 void qmp_guest_shutdown(const char *mode, Error **errp)
 {
     const char *shutdown_flag;