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

SSH_ASKPASS

OpenBSD-Commit-ID: 9484aea33aff5b62ce3642bf259546c7639f23f3

diff --git a/misc.h b/misc.h
index bcc34f980424d9ae4cd78f3b5c43d49416e35f0e..7421fbdf9384bb87e1fbdd12601c08988e17459f 100644 (file)
--- a/misc.h
+++ b/misc.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.h,v 1.81 2019/09/03 08:32:11 djm Exp $ */
+/* $OpenBSD: misc.h,v 1.82 2019/11/12 22:34:20 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -178,8 +178,13 @@ int        opt_match(const char **opts, const char *term);
 #define RP_ALLOW_EOF           0x0004
 #define RP_USE_ASKPASS         0x0008
 
+struct notifier_ctx;
+
 char   *read_passphrase(const char *, int);
 int     ask_permission(const char *, ...) __attribute__((format(printf, 1, 2)));
+struct notifier_ctx *notify_start(int, const char *, ...)
+       __attribute__((format(printf, 2, 3)));
+void   notify_complete(struct notifier_ctx *);
 
 #define MINIMUM(a, b)  (((a) < (b)) ? (a) : (b))
 #define MAXIMUM(a, b)  (((a) > (b)) ? (a) : (b))

diff --git a/readpass.c b/readpass.c
index 7e52cae9c5408f53b073a30150bd011c842fe7ff..33fc03bb7941ea007a67609d9bb5f1f75fc6627a 100644 (file)
--- 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);
+}