Make "wtap_dump()" and "wtap_dump_close()" return error codes, and check

for errors when closing a file to which we've written packets (we don't
bother checking if we're giving up on a capture).

Add some more error checks in Wiretap.

Make a single list of all Wiretap error codes, giving them all different
values (some can be returned by more than one routine, so they shouldn't
be per-routine).

svn path=/trunk/; revision=510

3 files changed, 67 insertions, 43 deletions

diff --git a/wiretap/file.c b/wiretap/file.c
index 0d10aa62b4..67106b2d96 100644
--- a/wiretap/file.c
+++ b/wiretap/file.c
@@ -1,6 +1,6 @@
 /* file.c
  *
- * $Id: file.c,v 1.14 1999/08/18 04:17:37 guy Exp $
+ * $Id: file.c,v 1.15 1999/08/18 04:41:19 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -51,7 +51,7 @@ wtap* wtap_open_offline(const char *filename, int *err)
 	wtap	*wth;
 
 	/* First, make sure the file is valid */
-	if (stat(filename, &statb)) {
+	if (stat(filename, &statb) < 0) {
 		*err = errno;
 		return NULL;
 	}
@@ -62,9 +62,15 @@ wtap* wtap_open_offline(const char *filename, int *err)
 	}
 #endif
 
+	errno = ENOMEM;
 	wth = (wtap*)malloc(sizeof(wtap));
+	if (wth == NULL) {
+		*err = errno;
+		return NULL;
+	}
 
 	/* Open the file */
+	errno = WTAP_ERR_CANT_OPEN;
 	if (!(wth->fh = fopen(filename, "rb"))) {
 		*err = errno;
 		free(wth);
@@ -201,20 +207,29 @@ FILE* wtap_dump_file(wtap_dumper *wdh)
 }
 
 int wtap_dump(wtap_dumper *wdh, const struct wtap_pkthdr *phdr,
-    const u_char *pd)
+    const u_char *pd, int *err)
 {
-	return (wdh->subtype_write)(wdh, phdr, pd);
+	return (wdh->subtype_write)(wdh, phdr, pd, err);
 }
 
-int wtap_dump_close(wtap_dumper *wdh)
+int wtap_dump_close(wtap_dumper *wdh, int *err)
 {
 	int ret = 1;
 
-	if (!(wdh->subtype_close)(wdh))
+	if (!(wdh->subtype_close)(wdh, err))
 		ret = 0;
+	errno = WTAP_ERR_CANT_CLOSE;
 	ret = fclose(wdh->fh);
-	if (ret == EOF)
+	if (ret == EOF) {
+		if (ret) {
+			/* The per-format close function succeeded,
+			   but the fclose didn't.  Save the reason
+			   why, if our caller asked for it. */
+			if (err != NULL)
+				*err = errno;
+		}
 		ret = 0;
+	}
 	free(wdh);
 	return ret;
 }
diff --git a/wiretap/libpcap.c b/wiretap/libpcap.c
index c44eeee62e..59e87f9954 100644
--- a/wiretap/libpcap.c
+++ b/wiretap/libpcap.c
@@ -1,6 +1,6 @@
 /* libpcap.c
  *
- * $Id: libpcap.c,v 1.7 1999/08/18 04:17:35 guy Exp $
+ * $Id: libpcap.c,v 1.8 1999/08/18 04:41:19 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -72,8 +72,8 @@ struct pcaprec_hdr {
 
 static int libpcap_read(wtap *wth);
 static int libpcap_dump(wtap_dumper *wdh, const struct wtap_pkthdr *phdr,
-    const u_char *pd);
-static int libpcap_dump_close(wtap_dumper *wdh);
+    const u_char *pd, int *err);
+static int libpcap_dump_close(wtap_dumper *wdh, int *err);
 
 static const int pcap_encap[] = {
 	WTAP_ENCAP_NONE,	/* no encapsulation */
@@ -298,7 +298,7 @@ int libpcap_dump_open(wtap_dumper *wdh, int *err)
 /* Write a record for a packet to a dump file.
    Returns 1 on success, 0 on failure. */
 static int libpcap_dump(wtap_dumper *wdh, const struct wtap_pkthdr *phdr,
-    const u_char *pd)
+    const u_char *pd, int *err)
 {
 	struct pcaprec_hdr rec_hdr;
 	int nwritten;
@@ -308,17 +308,28 @@ static int libpcap_dump(wtap_dumper *wdh, const struct wtap_pkthdr *phdr,
 	rec_hdr.incl_len = phdr->caplen;
 	rec_hdr.orig_len = phdr->len;
 	nwritten = fwrite(&rec_hdr, 1, sizeof rec_hdr, wdh->fh);
-	if (nwritten != sizeof rec_hdr)
-		return 0;	/* failed (XXX - save reason why) */
+	if (nwritten != sizeof rec_hdr) {
+		if (nwritten < 0)
+			*err = errno;
+		else
+			*err = WTAP_ERR_SHORT_WRITE;
+		return 0;
+	}
 	nwritten = fwrite(pd, 1, phdr->caplen, wdh->fh);
-	if (nwritten != phdr->caplen)
-		return 0;	/* failed (XXX - save reason why) */
+	if (nwritten != phdr->caplen) {
+		if (nwritten < 0)
+			*err = errno;
+		else
+			*err = WTAP_ERR_SHORT_WRITE;
+		return 0;
+	}
 	return 1;
 }
 
-/* Close a dump file.
+/* Finish writing to a dump file.
    Returns 1 on success, 0 on failure. */
-static int libpcap_dump_close(wtap_dumper *wdh)
+static int libpcap_dump_close(wtap_dumper *wdh, int *err)
 {
+	/* Nothing to do here. */
 	return 1;
 }
diff --git a/wiretap/wtap.h b/wiretap/wtap.h
index e1a7465460..db9c31f30a 100644
--- a/wiretap/wtap.h
+++ b/wiretap/wtap.h
@@ -1,6 +1,6 @@
 /* wtap.h
  *
- * $Id: wtap.h,v 1.24 1999/08/18 04:17:36 guy Exp $
+ * $Id: wtap.h,v 1.25 1999/08/18 04:41:20 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -176,8 +176,8 @@ typedef struct wtap {
 struct wtap_dumper;
 
 typedef int (*subtype_write_func)(struct wtap_dumper*,
-		const struct wtap_pkthdr*, const u_char*);
-typedef int (*subtype_close_func)(struct wtap_dumper *);
+		const struct wtap_pkthdr*, const u_char*, int*);
+typedef int (*subtype_close_func)(struct wtap_dumper*, int*);
 typedef struct wtap_dumper {
 	FILE*			fh;
 	int			file_type;
@@ -196,9 +196,6 @@ typedef struct wtap_dumper {
  *
  * a negative number, indicating the type of error, on other failures.
  */
-#define	WTAP_ERR_NOT_REGULAR_FILE	-1	/* not a plain file */
-#define	WTAP_ERR_FILE_UNKNOWN_FORMAT	-2	/* not a capture file in a known format */
-
 wtap* wtap_open_offline(const char *filename, int *err);
 void wtap_loop(wtap *wth, int, wtap_handler, u_char*);
 
@@ -208,35 +205,36 @@ int wtap_file_type(wtap *wth);
 const char *wtap_file_type_string(wtap *wth);
 void wtap_close(wtap *wth);
 
-/*
- * On failure, "wtap_dump_open()" and "wtap_dump_fdopen()" return NULL,
- * and put into the "int" pointed to by its second argument:
- *
- * a positive "errno" value if the capture file can't be created, or
- * some other failure that sets "errno" occurs;
- *
- * a negative number, indicating the type of error, on other failures.
- */
-#define	WTAP_ERR_CANT_OPEN			-1
-		/* couldn't open, reason unknown */
-#define	WTAP_ERR_UNSUPPORTED_FILE_TYPE		-2
-		/* can't save files in that format */
-#define	WTAP_ERR_ENCAP_PER_PACKET_UNSUPPORTED	-3
-		/* that format doesn't support per-packet encapsulations */
-#define	WTAP_ERR_SHORT_WRITE			-4
-		/* write wrote less data than it should have */
-
 wtap_dumper* wtap_dump_open(const char *filename, int filetype, int encap,
 	int snaplen, int *err);
 wtap_dumper* wtap_dump_fdopen(int fd, int filetype, int encap, int snaplen,
 	int *err);
-int wtap_dump(wtap_dumper *, const struct wtap_pkthdr *, const u_char *);
+int wtap_dump(wtap_dumper *, const struct wtap_pkthdr *, const u_char *,
+	int *err);
 FILE* wtap_dump_file(wtap_dumper *);
-int wtap_dump_close(wtap_dumper *);
+int wtap_dump_close(wtap_dumper *, int *);
 
 /* XXX - needed until "wiretap" can do live packet captures */
 int wtap_pcap_encap_to_wtap_encap(int encap);
 
+/*
+ * Wiretap error codes.
+ */
+#define	WTAP_ERR_NOT_REGULAR_FILE		-1
+	/* The file being opened for reading isn't a plain file */
+#define	WTAP_ERR_FILE_UNKNOWN_FORMAT		-2
+	/* The file being opened is not a capture file in a known format */
+#define	WTAP_ERR_CANT_OPEN			-3
+	/* The file couldn't be opened, reason unknown */
+#define	WTAP_ERR_UNSUPPORTED_FILE_TYPE		-4
+	/* Wiretap can't save files in the specified format */
+#define	WTAP_ERR_ENCAP_PER_PACKET_UNSUPPORTED	-5
+	/* The specified format doesn't support per-packet encapsulations */
+#define	WTAP_ERR_CANT_CLOSE			-6
+	/* The file couldn't be closed, reason unknown */
+#define	WTAP_ERR_SHORT_WRITE			-7
+	/* An attempt to write wrote less data than it should have */
+
 /* Pointer versions of ntohs and ntohl.  Given a pointer to a member of a
  * byte array, returns the value of the two or four bytes at the pointer.
  * The pletoh[sl] versions return the little-endian representation.