From: Alan Cox <alan@linux.intel.com>
Date: Tue, 30 Dec 2014 11:39:49 +0000 (+0000)
Subject: utils: add write from ELKS
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=155b1cd4194ab10a6eac46b06557f25749e8068a;p=FUZIX.git

utils: add write from ELKS
---

diff --git a/Applications/util/Makefile b/Applications/util/Makefile
index 2614877c..c71caf00 100644
--- a/Applications/util/Makefile
+++ b/Applications/util/Makefile
@@ -89,6 +89,7 @@ SRCS  = banner.c \
 	wc.c \
 	which.c \
 	whoami.c \
+	write.c \
 	xargs.c \
 	yes.c
 
diff --git a/Applications/util/write.c b/Applications/util/write.c
new file mode 100644
index 00000000..672ec6a5
--- /dev/null
+++ b/Applications/util/write.c
@@ -0,0 +1,104 @@
+/*
+ * write.c
+ *
+ * Copyright 2000 Alistair Riddoch
+ * ajr@ecs.soton.ac.uk
+ *
+ * This file may be distributed under the terms of the GNU General Public
+ * License v2, or at your option any later version.
+ */
+
+/*
+ * This is a small version of write for use in the ELKS project.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <pwd.h>
+#include <utmp.h>
+#include <fcntl.h>
+#include <string.h>
+
+#define TTYPREFIX "/dev/"
+
+void usage(char ** argv)
+{
+	fprintf(stderr, "%s user [ttyname]\n", argv[0]);
+	exit(1);
+}
+
+int main(int argc, char ** argv)
+{
+	char ttyname[12];
+	struct passwd * pwdent;
+	int ofd = -1;
+	char buf[255];
+	int n;
+
+	if ((argc > 3) || (argc < 2)) {
+		usage(argv);
+	}
+	if ((pwdent = getpwnam(argv[1])) == NULL) {
+		fprintf(stderr, "%s: No such user %s\n", argv[0], argv[1]);
+		exit(1);
+	}
+	if (argc == 3) {
+		struct stat sbuf;
+
+		strncpy(ttyname, TTYPREFIX, 6);
+		strncat(ttyname, argv[2], 6);
+		ttyname[11] = '\0';
+		if (stat(ttyname, &sbuf) != 0) {
+			fprintf(stderr, "%s: No such tty %s\n",
+				argv[0], ttyname);
+			exit(1);
+		}
+		if (pwdent->pw_uid != sbuf.st_uid) {
+			fprintf(stderr, "%s: User %s is not logged onto %s\n",
+				argv[0], argv[1], argv[2]);
+			exit(1);
+		}
+		if ((ofd = open(ttyname, O_WRONLY)) < 0) {
+			fprintf(stderr, "%s: %s has messages disabled on %s\n",
+				argv[0], argv[1], argv[2]);
+			exit(1);
+		}
+	} else { /* argc == 2 */
+		struct utmp * utmp;
+		setutent();
+		while ((utmp = getutent()) != NULL) {
+			if ((strcmp(pwdent->pw_name, utmp->ut_user) == 0) &&
+			    (utmp->ut_type == USER_PROCESS)) {
+				strncpy(ttyname, TTYPREFIX, 6);
+				strncat(ttyname, utmp->ut_line, 6);
+				ttyname[11] = '\0';
+				if ((ofd = open(ttyname, O_WRONLY)) >= 0) {
+					break;
+				}
+			}
+		}
+		if (ofd < 0) {
+			fprintf(stderr, "%s: User %s not logged in, or has messages disabled\n",
+				argv[0], argv[1]);
+			exit(1);
+		}
+	}
+	if ((pwdent = getpwnam(argv[1])) == NULL) {
+		fprintf(stderr, "%s: Who are you?\n", argv[0]);
+		exit(1);
+	}
+	write(ofd, "Message from ", 13);
+	write(ofd, pwdent->pw_name, strlen(pwdent->pw_name));
+	write(ofd, "\n", 1);
+	while ((n = read(STDIN_FILENO, buf, 254)) > 0) {
+		buf[254] = '\0';
+		write(ofd, buf, n);
+	}
+	write(ofd, "EOF\n", 4);
+	
+	exit(0);
+}