Attachment 99 Details for Bug 253 – Patch to write pid out to a file in daemon mode for ssh

[patch] Patch to write pid out to a file in daemon mode for ssh

openssh-3.2.2p1.withpid.diff (text/plain), 4.11 KB, created by Evan Prodromou on 2002-05-21 05:04:20 AEST

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Creator: Evan Prodromou

Created: 2002-05-21 05:04:20 AEST

Size: 4.11 KB

patch

obsolete

>diff -Naur openssh-3.2.2p1/ssh.1 openssh-3.2.2p1.withpid/ssh.1
>--- openssh-3.2.2p1/ssh.1	Wed May 15 21:36:46 2002
>+++ openssh-3.2.2p1.withpid/ssh.1	Mon May 20 18:22:22 2002
>@@ -51,6 +51,7 @@
> .Op Fl afgknqstvxACNPTX1246
> .Op Fl b Ar bind_address
> .Op Fl c Ar cipher_spec
>+.Op Fl d Ar pidfile
> .Op Fl e Ar escape_char
> .Op Fl i Ar identity_file
> .Op Fl l Ar login_name
>@@ -421,6 +422,17 @@
> See
> .Cm Ciphers
> for more information.
>+.It Fl d Ar pidfile
>+Requests
>+.Nm
>+to write a file containing the process ID before going into the background.
>+This implies
>+.Fl n 
>+and 
>+.Fl f .
>+This is useful to create tunnels to use in scripts, since they can 
>+then be killed with
>+.Ic kill `cat pidfile` .
> .It Fl e Ar ch|^ch|none
> Sets the escape character for sessions with a pty (default:
> .Ql ~ ) .
>diff -Naur openssh-3.2.2p1/ssh.c openssh-3.2.2p1.withpid/ssh.c
>--- openssh-3.2.2p1/ssh.c	Tue Apr 23 11:09:46 2002
>+++ openssh-3.2.2p1.withpid/ssh.c	Mon May 20 17:52:37 2002
>@@ -113,6 +113,14 @@
> int fork_after_authentication_flag = 0;
> 
> /*
>+ * Flag indicating that ssh should write its pid out to a file. Useful for
>+ * fork()'d clients.
>+ */
>+
>+int write_pid_flag = 0;
>+char *pidfile = NULL;
>+  
>+/*
>  * General data structure for command line options and options configurable
>  * in configuration files.  See readconf.h.
>  */
>@@ -180,6 +188,7 @@
> 	fprintf(stderr, "  -P          Don't allocate a privileged port.\n");
> 	fprintf(stderr, "  -q          Quiet; don't display any warning messages.\n");
> 	fprintf(stderr, "  -f          Fork into background after authentication.\n");
>+   	fprintf(stderr, "  -d file     Write daemon pid to file (implies -f).\n");
> 	fprintf(stderr, "  -e char     Set escape character; ``none'' = disable (default: ~).\n");
> 
> 	fprintf(stderr, "  -c cipher   Select encryption algorithm\n");
>@@ -244,6 +253,8 @@
> static int ssh_session(void);
> static int ssh_session2(void);
> static void load_public_identity_files(void);
>+static void write_pid(pid_t pid);
>+static pid_t go_daemon();
> 
> /*
>  * Main program for the ssh client.
>@@ -315,7 +326,7 @@
> 
> again:
> 	while ((opt = getopt(ac, av,
>-	    "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:NPR:TVX")) != -1) {
>+	    "1246ab:c:d:e:fgi:kl:m:no:p:qstvxACD:F:I:L:NPR:TVX")) != -1) {
> 		switch (opt) {
> 		case '1':
> 			options.protocol = SSH_PROTO_1;
>@@ -336,6 +347,12 @@
> 			fork_after_authentication_flag = 1;
> 			stdin_null_flag = 1;
> 			break;
>+		case 'd':
>+			write_pid_flag = 1;
>+			fork_after_authentication_flag = 1;
>+			stdin_null_flag = 1;
>+		        pidfile = optarg;
>+			break;
> 		case 'x':
> 			options.forward_x11 = 0;
> 			break;
>@@ -1001,8 +1018,7 @@
> 
> 	/* If requested, let ssh continue in the background. */
> 	if (fork_after_authentication_flag)
>-		if (daemon(1, 1) < 0)
>-			fatal("daemon() failed: %.200s", strerror(errno));
>+          go_daemon();
> 
> 	/*
> 	 * If a command was specified on the command line, execute the
>@@ -1200,8 +1216,7 @@
> 
> 	/* If requested, let ssh continue in the background. */
> 	if (fork_after_authentication_flag)
>-		if (daemon(1, 1) < 0)
>-			fatal("daemon() failed: %.200s", strerror(errno));
>+          go_daemon();
> 
> 	return client_loop(tty_flag, tty_flag ?
> 	    options.escape_char : SSH_ESCAPECHAR_NONE, id);
>@@ -1246,4 +1261,41 @@
> 		options.identity_files[i] = filename;
> 		options.identity_keys[i] = public;
> 	}
>+}
>+
>+/* We use this to go into daemon mode, rather than daemon(), because
>+ * we want the parent to write out the pid file before exiting, to
>+ * prevent any races for the pid file in scripts, etc. */
>+
>+static pid_t
>+go_daemon() {
>+  pid_t child_pid;
>+
>+  child_pid = fork();
>+
>+  if (child_pid == -1) {
>+    fatal("Couldn't fork child: %.200s", strerror(errno));
>+  } else if (child_pid == 0) {
>+    setsid();
>+  } else {
>+    if (write_pid_flag) 
>+      write_pid(child_pid);
>+    exit(0);
>+  }
>+
>+  return child_pid;
>+}
>+
>+/* Simple function to write a pid to a file. */
>+
>+static void
>+write_pid(pid_t pid) {
>+  FILE* f;
>+  f = fopen(pidfile, "wb"); /* no particular reason for "b", but sshd.c does it. */
>+  if (!f) {
>+    fatal("Can't write pid file %.100s: %.200s", pidfile, strerror(errno));
>+  } else {
>+    fprintf(f, "%u\n", (u_int) pid);
>+    fclose(f);
>+  }
> }

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