Replace sbuf_overflowed() with sbuf_error(), which returns any error

code associated with overflow or with the drain function.  While this
function is not expected to be used often, it produces more information
in the form of an errno that sbuf_overflowed() did.

9 files changed, 51 insertions, 48 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 6abafe1..194eba4 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1025,10 +1025,10 @@ MLINKS+=sbuf.9 sbuf_bcat.9 \
 	sbuf.9 sbuf_data.9 \
 	sbuf.9 sbuf_delete.9 \
 	sbuf.9 sbuf_done.9 \
+	sbuf.9 sbuf_error.9 \
 	sbuf.9 sbuf_finish.9 \
 	sbuf.9 sbuf_len.9 \
 	sbuf.9 sbuf_new.9 \
-	sbuf.9 sbuf_overflowed.9 \
 	sbuf.9 sbuf_printf.9 \
 	sbuf.9 sbuf_putc.9 \
 	sbuf.9 sbuf_set_drain.9 \
diff --git a/share/man/man9/sbuf.9 b/share/man/man9/sbuf.9
index 7389064..0b6aa90 100644
--- a/share/man/man9/sbuf.9
+++ b/share/man/man9/sbuf.9
@@ -45,7 +45,7 @@
 .Nm sbuf_putc ,
 .Nm sbuf_set_drain ,
 .Nm sbuf_trim ,
-.Nm sbuf_overflowed ,
+.Nm sbuf_error ,
 .Nm sbuf_finish ,
 .Nm sbuf_data ,
 .Nm sbuf_len ,
@@ -88,7 +88,7 @@
 .Ft int
 .Fn sbuf_trim "struct sbuf *s"
 .Ft int
-.Fn sbuf_overflowed "struct sbuf *s"
+.Fn sbuf_error "struct sbuf *s"
 .Ft int
 .Fn sbuf_finish "struct sbuf *s"
 .Ft char *
@@ -332,10 +332,15 @@ function removes trailing whitespace from the
 .Fa sbuf .
 .Pp
 The
-.Fn sbuf_overflowed
-function returns a non-zero value if the
+.Fn sbuf_error
+function returns any error value that the
+.Fa sbuf
+may have accumulated, either from the drain function, or ENOMEM if the
 .Fa sbuf
 overflowed.
+This function is generally not needed and instead the error code from
+.Fn sbuf_finish
+is the preferred way to discover whether an sbuf had an error.
 .Pp
 The
 .Fn sbuf_finish
@@ -437,9 +442,9 @@ functions
 all return \-1 if the buffer overflowed, and zero otherwise.
 .Pp
 The
-.Fn sbuf_overflowed
-function
-returns a non-zero value if the buffer overflowed, and zero otherwise.
+.Fn sbuf_error
+function returns a non-zero value if the buffer has an overflow or
+drain error, and zero otherwise.
 .Pp
 The
 .Fn sbuf_data
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_fm.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_fm.c
index 63ae13a..cf2f90d 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_fm.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_fm.c
@@ -101,6 +101,7 @@ zfs_ereport_post(const char *subclass, spa_t *spa, vdev_t *vd, zio_t *zio,
 	char buf[1024];
 	struct sbuf sb;
 	struct timespec ts;
+	int error;
 
 	/*
 	 * If we are doing a spa_tryimport(), ignore errors.
@@ -315,9 +316,9 @@ zfs_ereport_post(const char *subclass, spa_t *spa, vdev_t *vd, zio_t *zio,
 	}
 	mutex_exit(&spa->spa_errlist_lock);
 
-	sbuf_finish(&sb);
+	error = sbuf_finish(&sb);
 	devctl_notify("ZFS", spa->spa_name, subclass, sbuf_data(&sb));
-	if (sbuf_overflowed(&sb))
+	if (error != 0)
 		printf("ZFS WARNING: sbuf overflowed\n");
 	sbuf_delete(&sb);
 #endif
@@ -331,6 +332,7 @@ zfs_post_common(spa_t *spa, vdev_t *vd, const char *name)
 	char class[64];
 	struct sbuf sb;
 	struct timespec ts;
+	int error;
 
 	nanotime(&ts);
 
@@ -346,10 +348,10 @@ zfs_post_common(spa_t *spa, vdev_t *vd, const char *name)
 	if (vd)
 		sbuf_printf(&sb, " %s=%ju", FM_EREPORT_PAYLOAD_ZFS_VDEV_GUID,
 		    vd->vdev_guid);
-	sbuf_finish(&sb);
+	error = sbuf_finish(&sb);
 	ZFS_LOG(1, "%s", sbuf_data(&sb));
 	devctl_notify("ZFS", spa->spa_name, class, sbuf_data(&sb));
-	if (sbuf_overflowed(&sb))
+	if (error != 0)
 		printf("ZFS WARNING: sbuf overflowed\n");
 	sbuf_delete(&sb);
 #endif
diff --git a/sys/compat/linux/linux_ioctl.c b/sys/compat/linux/linux_ioctl.c
index b6de86a..07a281e 100644
--- a/sys/compat/linux/linux_ioctl.c
+++ b/sys/compat/linux/linux_ioctl.c
@@ -2220,7 +2220,7 @@ again:
 				addrs++;
 			}
 
-			if (!sbuf_overflowed(sb))
+			if (sbuf_error(sb) == 0)
 				valid_len = sbuf_len(sb);
 		}
 		if (addrs == 0) {
@@ -2228,7 +2228,7 @@ again:
 			sbuf_bcat(sb, &ifr, sizeof(ifr));
 			max_len += sizeof(ifr);
 
-			if (!sbuf_overflowed(sb))
+			if (sbuf_error(sb) == 0)
 				valid_len = sbuf_len(sb);
 		}
 	}
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index f54d59e..d315ff1 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -3093,7 +3093,7 @@ expand_name(const char *name, uid_t uid, pid_t pid, struct thread *td,
 		sbuf_printf(&sb, GZ_SUFFIX);
 	}
 #endif
-	if (sbuf_overflowed(&sb)) {
+	if (sbuf_error(&sb) != 0) {
 		log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
 		    "long\n", (long)pid, name, (u_long)uid);
 nomem:
diff --git a/sys/kern/subr_sbuf.c b/sys/kern/subr_sbuf.c
index 58964fb..4535337 100644
--- a/sys/kern/subr_sbuf.c
+++ b/sys/kern/subr_sbuf.c
@@ -66,7 +66,6 @@ static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
 #define	SBUF_ISDYNAMIC(s)	((s)->s_flags & SBUF_DYNAMIC)
 #define	SBUF_ISDYNSTRUCT(s)	((s)->s_flags & SBUF_DYNSTRUCT)
 #define	SBUF_ISFINISHED(s)	((s)->s_flags & SBUF_FINISHED)
-#define	SBUF_HASOVERFLOWED(s)	((s)->s_flags & SBUF_OVERFLOWED)
 #define	SBUF_HASROOM(s)		((s)->s_len < (s)->s_size - 1)
 #define	SBUF_FREESPACE(s)	((s)->s_size - (s)->s_len - 1)
 #define	SBUF_CANEXTEND(s)	((s)->s_flags & SBUF_AUTOEXTEND)
@@ -247,7 +246,6 @@ sbuf_clear(struct sbuf *s)
 	/* don't care if it's finished or not */
 
 	SBUF_CLEARFLAG(s, SBUF_FINISHED);
-	SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
 	s->s_error = 0;
 	s->s_len = 0;
 }
@@ -299,10 +297,10 @@ sbuf_drain(struct sbuf *s)
 	int len;
 
 	KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s));
+	KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s));
 	len = s->s_drain_func(s->s_drain_arg, s->s_buf, s->s_len);
 	if (len < 0) {
 		s->s_error = -len;
-		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
 		return (s->s_error);
 	}
 	KASSERT(len > 0 && len <= s->s_len,
@@ -334,7 +332,7 @@ sbuf_put_byte(int c, struct sbuf *s)
 	assert_sbuf_integrity(s);
 	assert_sbuf_state(s, 0);
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return;
 	if (SBUF_FREESPACE(s) <= 0) {
 		/* 
@@ -344,8 +342,8 @@ sbuf_put_byte(int c, struct sbuf *s)
 		if (s->s_drain_func != NULL)
 			(void)sbuf_drain(s);
 		else if (sbuf_extend(s, 1) < 0)
-			SBUF_SETFLAG(s, SBUF_OVERFLOWED);
-		if (SBUF_HASOVERFLOWED(s))
+			s->s_error = ENOMEM;
+		if (s->s_error != 0)
 			return;
 	}
 	s->s_buf[s->s_len++] = c;
@@ -375,11 +373,11 @@ sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
 	assert_sbuf_integrity(s);
 	assert_sbuf_state(s, 0);
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 	for (; str < end; str++) {
 		sbuf_put_byte(*str, s);
-		if (SBUF_HASOVERFLOWED(s))
+		if (s->s_error != 0)
 			return (-1);
  	}
 	return (0);
@@ -398,7 +396,7 @@ sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
 	KASSERT(s->s_drain_func == NULL,
 	    ("Nonsensical copyin to sbuf %p with a drain", s));
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 	if (len == 0)
 		return (0);
@@ -439,12 +437,12 @@ sbuf_cat(struct sbuf *s, const char *str)
 	assert_sbuf_integrity(s);
 	assert_sbuf_state(s, 0);
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 
 	while (*str != '\0') {
 		sbuf_put_byte(*str, s);
-		if (SBUF_HASOVERFLOWED(s))
+		if (s->s_error != 0)
 			return (-1);
 	}
 	return (0);
@@ -464,7 +462,7 @@ sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
 	KASSERT(s->s_drain_func == NULL,
 	    ("Nonsensical copyin to sbuf %p with a drain", s));
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 
 	if (len == 0)
@@ -476,7 +474,7 @@ sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
 	}
 	switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
 	case ENAMETOOLONG:
-		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
+		s->s_error = ENOMEM;
 		/* fall through */
 	case 0:
 		s->s_len += done - 1;
@@ -518,7 +516,7 @@ sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
 	    ("%s called with a NULL format string", __func__));
 
 	(void)kvprintf(fmt, sbuf_putc_func, s, 10, ap);
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 	return (0);
 }
@@ -535,7 +533,7 @@ sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
 	KASSERT(fmt != NULL,
 	    ("%s called with a NULL format string", __func__));
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 
 	/*
@@ -578,12 +576,12 @@ sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
 		len = SBUF_FREESPACE(s);
 	s->s_len += len;
 	if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
-		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
+		s->s_error = ENOMEM;
 
 	KASSERT(s->s_len < s->s_size,
 	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 	return (0);
 }
@@ -612,7 +610,7 @@ sbuf_putc(struct sbuf *s, int c)
 {
 
 	sbuf_putc_func(c, s);
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 	return (0);
 }
@@ -629,7 +627,7 @@ sbuf_trim(struct sbuf *s)
 	KASSERT(s->s_drain_func == NULL,
 	    ("%s makes no sense on sbuf %p with drain", __func__, s));
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 
 	while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1]))
@@ -639,13 +637,13 @@ sbuf_trim(struct sbuf *s)
 }
 
 /*
- * Check if an sbuf overflowed
+ * Check if an sbuf has an error.
  */
 int
-sbuf_overflowed(struct sbuf *s)
+sbuf_error(struct sbuf *s)
 {
 
-	return (SBUF_HASOVERFLOWED(s));
+	return (s->s_error);
 }
 
 /*
@@ -654,19 +652,18 @@ sbuf_overflowed(struct sbuf *s)
 int
 sbuf_finish(struct sbuf *s)
 {
-	int error = 0;
+	int error;
 
 	assert_sbuf_integrity(s);
 	assert_sbuf_state(s, 0);
 
+	error = s->s_error;
 	if (s->s_drain_func != NULL) {
-		error = s->s_error;
 		while (s->s_len > 0 && error == 0)
 			error = sbuf_drain(s);
-	} else if (SBUF_HASOVERFLOWED(s))
-		error = ENOMEM;
+	}
 	s->s_buf[s->s_len] = '\0';
-	SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
+	s->s_error = 0;
 	SBUF_SETFLAG(s, SBUF_FINISHED);
 #ifdef _KERNEL
 	return (error);
@@ -703,7 +700,7 @@ sbuf_len(struct sbuf *s)
 	KASSERT(s->s_drain_func == NULL,
 	    ("%s makes no sense on sbuf %p with drain", __func__, s));
 
-	if (SBUF_HASOVERFLOWED(s))
+	if (s->s_error != 0)
 		return (-1);
 	return (s->s_len);
 }
diff --git a/sys/net/if.c b/sys/net/if.c
index c387dbf..bd54acf 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -2726,7 +2726,7 @@ again:
 				max_len += sa->sa_len;
 			}
 
-			if (!sbuf_overflowed(sb))
+			if (sbuf_error(sb) == 0)
 				valid_len = sbuf_len(sb);
 		}
 		IF_ADDR_UNLOCK(ifp);
@@ -2735,7 +2735,7 @@ again:
 			sbuf_bcat(sb, &ifr, sizeof(ifr));
 			max_len += sizeof(ifr);
 
-			if (!sbuf_overflowed(sb))
+			if (sbuf_error(sb) == 0)
 				valid_len = sbuf_len(sb);
 		}
 	}
diff --git a/sys/security/audit/audit_bsm_klib.c b/sys/security/audit/audit_bsm_klib.c
index c8d4035..f26f86c 100644
--- a/sys/security/audit/audit_bsm_klib.c
+++ b/sys/security/audit/audit_bsm_klib.c
@@ -548,7 +548,7 @@ audit_canon_path(struct thread *td, char *path, char *cpath)
 	 * the supplied buffer being overflowed.  Check to see if this is the
 	 * case.
 	 */
-	if (sbuf_overflowed(&sbf) != 0) {
+	if (sbuf_error(&sbf) != 0) {
 		cpath[0] = '\0';
 		return;
 	}
diff --git a/sys/sys/sbuf.h b/sys/sys/sbuf.h
index be3d80c..eeb3814 100644
--- a/sys/sys/sbuf.h
+++ b/sys/sys/sbuf.h
@@ -51,7 +51,6 @@ struct sbuf {
 #define	SBUF_USRFLAGMSK	0x0000ffff	/* mask of flags the user may specify */
 #define	SBUF_DYNAMIC	0x00010000	/* s_buf must be freed */
 #define	SBUF_FINISHED	0x00020000	/* set by sbuf_finish() */
-#define	SBUF_OVERFLOWED	0x00040000	/* sbuf overflowed */
 #define	SBUF_DYNSTRUCT	0x00080000	/* sbuf must be freed */
 	int		 s_flags;	/* flags */
 };
@@ -76,7 +75,7 @@ int		 sbuf_vprintf(struct sbuf *, const char *, __va_list)
 int		 sbuf_putc(struct sbuf *, int);
 void		 sbuf_set_drain(struct sbuf *, sbuf_drain_func *, void *);
 int		 sbuf_trim(struct sbuf *);
-int		 sbuf_overflowed(struct sbuf *);
+int		 sbuf_error(struct sbuf *);
 int		 sbuf_finish(struct sbuf *);
 char		*sbuf_data(struct sbuf *);
 int		 sbuf_len(struct sbuf *);