upstream: dd API for performing one-shot notifications via tty or

SSH_ASKPASS

OpenBSD-Commit-ID: 9484aea33aff5b62ce3642bf259546c7639f23f3

1 files changed, 85 insertions, 1 deletions

diff --git a/readpass.c b/readpass.c
index 7e52cae9c..33fc03bb7 100644
--- a/readpass.c
+++ b/readpass.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: readpass.c,v 1.54 2019/06/28 13:35:04 deraadt Exp $ */
+/* $OpenBSD: readpass.c,v 1.55 2019/11/12 22:34:20 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -197,3 +197,87 @@ ask_permission(const char *fmt, ...)
 
         return (allowed);
 }
+
+struct notifier_ctx {
+        pid_t pid;
+        void (*osigchld)(int);
+};
+
+struct notifier_ctx *
+notify_start(int force_askpass, const char *fmt, ...)
+{
+        va_list args;
+        char *prompt = NULL;
+        int devnull;
+        pid_t pid;
+        void (*osigchld)(int);
+        const char *askpass;
+        struct notifier_ctx *ret;
+
+        va_start(args, fmt);
+        xvasprintf(&prompt, fmt, args);
+        va_end(args);
+
+        if (fflush(NULL) != 0)
+                error("%s: fflush: %s", __func__, strerror(errno));
+        if (!force_askpass && isatty(STDERR_FILENO)) {
+                (void)write(STDERR_FILENO, "\r", 1);
+                (void)write(STDERR_FILENO, prompt, strlen(prompt));
+                (void)write(STDERR_FILENO, "\r\n", 2);
+                free(prompt);
+                return NULL;
+        }
+        if (getenv("DISPLAY") == NULL ||
+            (askpass = getenv("SSH_ASKPASS")) == NULL || *askpass == '\0') {
+                debug3("%s: cannot notify", __func__);
+                free(prompt);
+                return NULL;
+        }
+        osigchld = signal(SIGCHLD, SIG_DFL);
+        if ((pid = fork()) == -1) {
+                error("%s: fork: %s", __func__, strerror(errno));
+                signal(SIGCHLD, osigchld);
+                free(prompt);
+                return NULL;
+        }
+        if (pid == 0) {
+                if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1)
+                        fatal("%s: open %s", __func__, strerror(errno));
+                if (dup2(devnull, STDIN_FILENO) == -1 ||
+                    dup2(devnull, STDOUT_FILENO) == -1)
+                        fatal("%s: dup2: %s", __func__, strerror(errno));
+                closefrom(STDERR_FILENO + 1);
+                setenv("SSH_ASKPASS_PROMPT", "none", 1); /* hint to UI */
+                execlp(askpass, askpass, prompt, (char *)NULL);
+                fatal("%s: exec(%s): %s", __func__, askpass, strerror(errno));
+                /* NOTREACHED */
+        }
+        if ((ret = calloc(1, sizeof(*ret))) == NULL) {
+                kill(pid, SIGTERM);
+                fatal("%s: calloc failed", __func__);
+        }
+        ret->pid = pid;
+        ret->osigchld = osigchld;
+        free(prompt);
+        return ret;
+}
+
+void
+notify_complete(struct notifier_ctx *ctx)
+{
+        int ret;
+
+        if (ctx == NULL || ctx->pid <= 0) {
+                free(ctx);
+                return;
+        }
+        kill(ctx->pid, SIGTERM);
+        while ((ret = waitpid(ctx->pid, NULL, 0)) == -1) {
+                if (errno != EINTR)
+                        break;
+        }
+        if (ret == -1)
+                fatal("%s: waitpid: %s", __func__, strerror(errno));
+        signal(SIGCHLD, ctx->osigchld);
+        free(ctx);
+}