httpd shrink and logging update, part 7 of 7

text    data     bss     dec     hex filename
   9836       0       0    9836    266c busybox.t1/networking/httpd.o.orig
   9724       0       0    9724    25fc busybox.t2/networking/httpd.o
   9657       0       0    9657    25b9 busybox.t3/networking/httpd.o
   9342       0       0    9342    247e busybox.t4/networking/httpd.o
   9342       0       0    9342    247e busybox.t5/networking/httpd.o
   9262       0       0    9262    242e busybox.t6/networking/httpd.o
   9283       0       0    9283    2443 busybox.t7/networking/httpd.o
   9334       0       0    9334    2476 busybox.t8/networking/httpd.o

networking/httpd.c

@@ -934,57 +934,20 @@ static void send_cgi_and_exit(
 {
 	struct { int rd; int wr; } fromCgi;  /* CGI -> httpd pipe */
 	struct { int rd; int wr; } toCgi;    /* httpd -> CGI pipe */
-	char *argp[] = { NULL, NULL };
-	int pid = 0;
-	int buf_count;
-	int status;
-	size_t post_read_size, post_read_idx;
-
-	xpipe(&fromCgi.rd);
-	xpipe(&toCgi.rd);
-
-/*
- * Note: We can use vfork() here in the no-mmu case, although
- * the child modifies the parent's variables, due to:
- * 1) The parent does not use the child-modified variables.
- * 2) The allocated memory (in the child) is freed when the process
- *    exits. This happens instantly after the child finishes,
- *    since httpd is run from inetd (and it can't run standalone
- *    in uClinux).
- * TODO: we can muck with environment _first_ and then fork/exec,
- * that will be more understandable, and safer wrt vfork!
- */
-
-#if !BB_MMU
-	pid = vfork();
-#else
-	pid = fork();
-#endif
-	if (pid < 0) {
-		/* TODO: log perror? */
-		log_and_exit();
-	}
-
-	if (!pid) {
-		/* child process */
 	char *fullpath;
 	char *script;
 	char *purl;
+	size_t post_read_size, post_read_idx;
+	int buf_count;
+	int status;
+	int pid = 0;
+	int sv_accepted_socket = accepted_socket;
 
-		xfunc_error_retval = 242;
+	/*
-
+	 * We are mucking with environment _first_ and then vfork/exec,
-		if (accepted_socket > 1)
+	 * this allows us to use vfork safely. Parent don't care about
-			close(accepted_socket);
+	 * these environment changes anyway.
-		if (server_socket > 1)
+	 */
-			close(server_socket);
-
-		xmove_fd(toCgi.rd, 0);  /* replace stdin with the pipe */
-		xmove_fd(fromCgi.wr, 1);  /* replace stdout with the pipe */
-		close(fromCgi.rd);
-		close(toCgi.wr);
-		/* Huh? User seeing stderr can be a security problem.
-		 * If CGI really wants that, it can always do dup itself. */
-		/* dup2(1, 2); */
 
 	/*
 	 * Find PATH_INFO.
@@ -1062,15 +1025,40 @@ static void send_cgi_and_exit(
 	if (referer)
 		setenv1("HTTP_REFERER", referer);
 
-		/* set execve argp[0] without path */
+	xpipe(&fromCgi.rd);
-		argp[0] = (char*)bb_basename(purl);
+	xpipe(&toCgi.rd);
-		/* but script argp[0] must have absolute path */
+
+	pid = vfork();
+	if (pid < 0) {
+		/* TODO: log perror? */
+		log_and_exit();
+	}
+
+	if (!pid) {
+		/* Child process */
+		xfunc_error_retval = 242;
+
+		if (accepted_socket > 1)
+			close(accepted_socket);
+		if (server_socket > 1)
+			close(server_socket);
+
+		xmove_fd(toCgi.rd, 0);  /* replace stdin with the pipe */
+		xmove_fd(fromCgi.wr, 1);  /* replace stdout with the pipe */
+		close(fromCgi.rd);
+		close(toCgi.wr);
+		/* User seeing stderr output can be a security problem.
+		 * If CGI really wants that, it can always do dup itself. */
+		/* dup2(1, 2); */
+
+		/* script must have absolute path */
 		script = strrchr(fullpath, '/');
 		if (!script)
 			goto error_execing_cgi;
 		*script = '\0';
 		/* chdiring to script's dir */
 		if (chdir(fullpath) == 0) {
+			char *argv[2];
 #if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
 			char *interpr = NULL;
 			char *suffix = strrchr(purl, '.');
@@ -1086,12 +1074,15 @@ static void send_cgi_and_exit(
 			}
 #endif
 			*script = '/';
+			/* set argv[0] to name without path */
+			argv[0] = (char*)bb_basename(purl);
+			argv[1] = NULL;
 #if ENABLE_FEATURE_HTTPD_CONFIG_WITH_SCRIPT_INTERPR
 			if (interpr)
-				execv(interpr, argp);
+				execv(interpr, argv);
 			else
 #endif
-				execv(fullpath, argp);
+				execv(fullpath, argv);
 		}
  error_execing_cgi:
 		/* send to stdout
@@ -1100,7 +1091,13 @@ static void send_cgi_and_exit(
 		send_headers_and_exit(HTTP_NOT_FOUND);
 	} /* end child */
 
-	/* parent process */
+	/* Parent process */
+
+	/* First, restore variables possibly changed by child */
+	xfunc_error_retval = 0;
+	accepted_socket = sv_accepted_socket;
+
+	/* Prepare for pumping data */
 	buf_count = 0;
 	post_read_size = 0;
 	post_read_idx = 0; /* for gcc */