Centralise calls to fcntl into functions that carefully check the

[sgt/putty] / unix / uxmisc.c

diff --git a/unix/uxmisc.c b/unix/uxmisc.c
index 300fc54..473aa94 100644 (file)
--- a/unix/uxmisc.c
+++ b/unix/uxmisc.c
@@ -6,6 +6,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
+#include <errno.h>
 #include <unistd.h>
 #include <time.h>
 #include <sys/time.h>
@@ -168,14 +169,70 @@ void pgp_fingerprints(void)
 }
 
 /*
- * Set FD_CLOEXEC on a file descriptor
+ * Set and clear fcntl options on a file descriptor. We don't
+ * realistically expect any of these operations to fail (the most
+ * plausible error condition is EBADF, but we always believe ourselves
+ * to be passing a valid fd so even that's an assertion-fail sort of
+ * response), so we don't make any effort to return sensible error
+ * codes to the caller - we just log to standard error and die
+ * unceremoniously. However, nonblock and no_nonblock do return the
+ * previous state of O_NONBLOCK.
  */
-int cloexec(int fd) {
+void cloexec(int fd) {
     int fdflags;
 
     fdflags = fcntl(fd, F_GETFD);
-    if (fdflags == -1) return -1;
-    return fcntl(fd, F_SETFD, fdflags | FD_CLOEXEC);
+    if (fdflags < 0) {
+        fprintf(stderr, "%d: fcntl(F_GETFD): %s\n", fd, strerror(errno));
+        exit(1);
+    }
+    if (fcntl(fd, F_SETFD, fdflags | FD_CLOEXEC) < 0) {
+        fprintf(stderr, "%d: fcntl(F_SETFD): %s\n", fd, strerror(errno));
+        exit(1);
+    }
+}
+void noncloexec(int fd) {
+    int fdflags;
+
+    fdflags = fcntl(fd, F_GETFD);
+    if (fdflags < 0) {
+        fprintf(stderr, "%d: fcntl(F_GETFD): %s\n", fd, strerror(errno));
+        exit(1);
+    }
+    if (fcntl(fd, F_SETFD, fdflags & ~FD_CLOEXEC) < 0) {
+        fprintf(stderr, "%d: fcntl(F_SETFD): %s\n", fd, strerror(errno));
+        exit(1);
+    }
+}
+int nonblock(int fd) {
+    int fdflags;
+
+    fdflags = fcntl(fd, F_GETFL);
+    if (fdflags < 0) {
+        fprintf(stderr, "%d: fcntl(F_GETFL): %s\n", fd, strerror(errno));
+        exit(1);
+    }
+    if (fcntl(fd, F_SETFL, fdflags | O_NONBLOCK) < 0) {
+        fprintf(stderr, "%d: fcntl(F_SETFL): %s\n", fd, strerror(errno));
+        exit(1);
+    }
+
+    return fdflags & O_NONBLOCK;
+}
+int no_nonblock(int fd) {
+    int fdflags;
+
+    fdflags = fcntl(fd, F_GETFL);
+    if (fdflags < 0) {
+        fprintf(stderr, "%d: fcntl(F_GETFL): %s\n", fd, strerror(errno));
+        exit(1);
+    }
+    if (fcntl(fd, F_SETFL, fdflags & ~O_NONBLOCK) < 0) {
+        fprintf(stderr, "%d: fcntl(F_SETFL): %s\n", fd, strerror(errno));
+        exit(1);
+    }
+
+    return fdflags & O_NONBLOCK;
 }
 
 FILE *f_open(const Filename *filename, char const *mode, int is_private)