display proper error messages for read/write.

after a lot of bickering with tedu...

"fine, fix it" tedu@

diff --git a/usr.bin/signify/signify.c b/usr.bin/signify/signify.c
index 1b5339c..dc74b5e 100644 (file)
--- a/usr.bin/signify/signify.c
+++ b/usr.bin/signify/signify.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: signify.c,v 1.6 2014/01/01 17:50:33 tedu Exp $ */
+/* $OpenBSD: signify.c,v 1.7 2014/01/02 16:34:02 espie Exp $ */
 /*
  * Copyright (c) 2013 Ted Unangst <tedu@openbsd.org>
  *
@@ -92,10 +92,14 @@ xmalloc(size_t len)
 }
 
 static void
-readall(int fd, void *buf, size_t len)
+readall(int fd, void *buf, size_t len, const char *filename)
 {
-       if (read(fd, buf, len) != len)
-               err(1, "read");
+       ssize_t x = read(fd, buf, len);
+       if (x == -1) {
+               err(1, "read from %s", filename);
+       } else if (x != len) {
+               errx(1, "short read from %s", filename);
+       }
 }
 
 static void
@@ -108,7 +112,7 @@ readb64file(const char *filename, void *buf, size_t len)
        memset(b64, 0, sizeof(b64));
        rv = read(fd, b64, sizeof(b64) - 1);
        if (rv == -1)
-               err(1, "read in %s", filename);
+               err(1, "read from %s", filename);
        for (i = 0; i < rv; i++)
                if (b64[i] == '\n')
                        break;
@@ -137,7 +141,7 @@ readmsg(const char *filename, unsigned long long *msglenp)
        if (msglen > (1UL << 30))
                errx(1, "msg too large in %s", filename);
        msg = xmalloc(msglen);
-       readall(fd, msg, msglen);
+       readall(fd, msg, msglen, filename);
        close(fd);
 
        *msglenp = msglen;
@@ -145,10 +149,14 @@ readmsg(const char *filename, unsigned long long *msglenp)
 }
 
 static void
-writeall(int fd, const void *buf, size_t len)
+writeall(int fd, const void *buf, size_t len, const char *filename)
 {
-       if (write(fd, buf, len) != len)
-               err(1, "write");
+       ssize_t x = write(fd, buf, len);
+       if (x == -1) {
+               err(1, "write to %s", filename);
+       } else if (x != len) {
+               errx(1, "short write to %s", filename);
+       }
 }
 
 static void
@@ -161,10 +169,10 @@ writeb64file(const char *filename, const char *comment, const void *buf,
 
        fd = xopen(filename, O_CREAT|O_EXCL|O_NOFOLLOW|O_RDWR, mode);
        snprintf(header, sizeof(header), "signify -- %s\n", comment);
-       writeall(fd, header, strlen(header));
+       writeall(fd, header, strlen(header), filename);
        if ((rv = b64_ntop(buf, len, b64, sizeof(b64))) == -1)
                errx(1, "b64 encode failed");
-       writeall(fd, b64, rv);
+       writeall(fd, b64, rv, filename);
        memset(b64, 0, sizeof(b64));
        close(fd);
 }