urshd: prevent warnings when building debug version

When building on GCC 5.4.0 with --enable-debug, -Werror is in effect:

  make[2]: Entering directory 'urshd-1.0.2/src'
  arm-v7a-linux-gnueabi-gcc -DHAVE_CONFIG_H -I. -I../include     -Wall -Wsign-compare -Wfloat-equal -Wformat-security -Werror -g -O1 -MT urshd.o -MD -MP -MF .deps/urshd.Tpo -c -o urshd.o urshd.c
  urshd.c: In function 'mainloop':
  urshd.c:582:1: error: no return statement in function returning non-void [-Werror=return-type]
  urshd.c:541:3: error: ignoring return value of 'daemon', declared with attribute warn_unused_result [-Werror=unused-result]
  urshd.c: In function 'doit':
  urshd.c:340:3: error: ignoring return value of 'chdir', declared with attribute warn_unused_result [-Werror=unused-result]
  urshd.c:352:2: error: ignoring return value of 'write', declared with attribute warn_unused_result [-Werror=unused-result]
  urshd.c: In function 'error':
  urshd.c:203:5: error: ignoring return value of 'write', declared with attribute warn_unused_result [-Werror=unused-result]
  urshd.c: In function 'stderr_parent':
  urshd.c:277:3: error: ignoring return value of 'write', declared with attribute warn_unused_result [-Werror=unused-result]
  cc1: all warnings being treated as errors
  GNUmakefile:231: recipe for target 'urshd.o' failed
  make[2]: *** [urshd.o] Error 1
  make[2]: Leaving directory 'urshd-1.0.2/src'

Use this opportunity to improve error handling.

Signed-off-by: Roland Hieber <r.hieber@pengutronix.de>

1 files changed, 21 insertions, 12 deletions

diff --git a/src/urshd.c b/src/urshd.c
index 0877113..a8eb868 100644
--- a/src/urshd.c
+++ b/src/urshd.c
@@ -201,7 +201,9 @@ error(const char *fmt, ...)
     vsnprintf(bp, sizeof(buf) - 1, fmt, ap);
     va_end(ap);
 
-    write(2, buf, strlen(buf));
+    if (write(2, buf, strlen(buf)) != 0) {
+        fatal("error: write: %m");
+    }
 }
 
 static void
@@ -274,8 +276,11 @@ stderr_parent(int sock, int pype, int pid)
 		shutdown(sock, 2);
 		FD_CLR(pype, &readfrom);
 		guys--;
-	    } else
-		write(sock, buf, cc);
+	    } else {
+		if (write(sock, buf, cc) != 0) {
+		    fatal("stderr_parent: %m");
+		}
+	    }
 	}
     }
 
@@ -338,11 +343,10 @@ doit(struct sockaddr_in *fromp)
 	}
 
 	if (chdir(pwd->pw_dir) < 0) {
-		chdir("/");
-		/*
-		 * error("No remote directory.\n");
-		 * exit(1);
-		 */
+		if (chdir("/") != 0) {
+			error("No remote directory.\n");
+			exit(1);
+		}
 	}
 
 	if (pwd->pw_uid != 0 && !access(_PATH_NOLOGIN, F_OK)) {
@@ -350,7 +354,9 @@ doit(struct sockaddr_in *fromp)
 		exit(1);
 	}
 
-	(void) write(2, "\0", 1);
+	if (write(2, "\0", 1) != 0) {
+		fatal("Unable to write: %m");
+	}
 	sent_null = 1;
 
 	if (port) {
@@ -502,7 +508,7 @@ network_init(int fd, struct sockaddr_in *fromp)
 #endif
 }
 
-static int
+static void
 mainloop(char *port)
 {
 	int s;
@@ -536,8 +542,11 @@ mainloop(char *port)
 		sn.sin_port = sp->s_port;
 	}
 
-	if (opt_daemon)
-		daemon(0, 0);
+	if (opt_daemon) {
+		if (daemon(0, 0) != 0) {
+			fatal("Could not fork: %s", strerror(errno));
+		}
+	}
 
 	s = socket(AF_INET, SOCK_STREAM, 0);
 	if (s < 0) {