[tools/bgpgrep] Add support for -o option

tools/bgpgrep/bgpgrep.1.in

@@ -17,7 +17,9 @@ utility reads each possibly compressed Multithreaded Routing Toolkit
 (MRT)
 dump file specified by
 .IR FILES
-and formats its contents to standard output.
+and formats its contents to standard output (or any custom output file
+as specified by
+.IR OPTIONS ).
 .IR @UTILITY@
 may optionally evaluate a predicate defined by
 .IR EXPRESSION
@@ -37,8 +39,8 @@ regardless of any filtering rule.
 prints diagnostics to standard error,
 it detects and tolerates data corruption as much as possible.
 Corruption within a BGP message causes only the affected message to be
-dropped. Unrecoverable corruption within the entire MRT dump file causes
+dropped. Though unrecoverable errors affecting the entire MRT dump file may
-the whole file to be dropped,
+require it to be dropped as a whole,
 .IR @UTILITY@
 will then move to the next file in
 .IR FILES ,
@@ -46,7 +48,7 @@ if any.
 .P
 Such events are always reported with reasonable diagnostic errors.
 Parsed data up to the corruption point may still be printed to
-standard output.
+regular output.
 
 .SH OPTIONS
 .IR @UTILITY@
@@ -74,6 +76,15 @@ may ease visualization by surrounding some output with color escape sequences,
 on terminals that support this feature. This option forces colored text
 output off.
 
+.IP "\fB\-o \fI<file>\fP" 10
+Write output to
+.BR file .
+Instead of using standard output,
+.IR @UTILITY@
+shall format MRT contents to the specified file. If option occurs
+multiple times, last specified file is used. This option forces colored
+text output off.
+
 .IP "\fB\-h or \-\-help\fP" 10
 Prints a short help message, summarizing
 .IR @UTILITY@
@@ -582,8 +593,11 @@ supported compression formats. If the file extension is not recognized,
 or there is no extension, then it is assumed to be uncompressed.
 
 .SH STDOUT
-The standard output is used to print a human readable text representation of
+Unless redirected explicitly via
-BGP message data, nothing else shall be written to the standard output.
+.IR OPTIONS ,
+the standard output is used to print a human readable text
+representation of BGP message data, nothing else shall be written
+to the standard output.
 .IR @UTILITY@
 may detect and treat as error whenever the standard output is a regular file,
 and is the same file as any of the
@@ -597,7 +611,9 @@ section.
 
 .SH STDERR
 The standard error is used only for diagnostic messages and error reporting.
-Any BGP message output is exclusive to standard output.
+Any BGP message output is exclusive to standard output or any file explicitly
+specified by
+.IR OPTIONS .
 
 .SH EXAMPLES
 This section contains some useful examples, starting from trivial ones,

tools/bgpgrep/bgpgrep.c

@@ -38,6 +38,7 @@ BgpgrepState S;
 typedef enum {
 	NO_COLOR_FLAG,
 	DUMP_BYTECODE_FLAG,
+	OUTPUT_FLAG,
 
 	NUM_FLAGS
 } BgpgrepOpt;
@@ -49,6 +50,9 @@ static Optflag options[] = {
 	[DUMP_BYTECODE_FLAG] = {
 		'-', "dump-bytecode", NULL, "Dump BGP VM bytecode to stderr (debug)", ARG_NONE
 	},
+	[OUTPUT_FLAG] = {
+		'o', NULL, "file", "Write output to file", ARG_REQ
+	},
 
 	[NUM_FLAGS] = { '\0' }
 };
@@ -63,34 +67,14 @@ static void Bgpgrep_SetupCommandLine(char *argv0)
 	com_shortDescr = "Filter and print BGP data within MRT dumps";
 	com_longDescr  =
 		"Reads MRT dumps in various formats, applying filtering rules\n"
-		"to each BGP message therein, then outputs every passing message to stdout.\n"
+		"to each BGP message therein, then outputs every passing message\n"
+		"to stdout (or any custom output file defined by OPTIONS).\n"
 		"If - is found inside FILES, then input is read from stdin.\n"
 		"If no FILES arguments are provided, then input\n"
 		"is implicitly expected from stdin.\n"
 		"Any diagnostic message is logged to stderr.";
 }
 
-static void Bgpgrep_ApplyProgramOptions(void)
-{
-	S.noColor      = options[NO_COLOR_FLAG].flagged;
-	S.dumpBytecode = options[DUMP_BYTECODE_FLAG].flagged;
-}
-
-static int CountFileArguments(int argc, char **argv)
-{
-	int i;
-
-	for (i = 0; i < argc; i++) {
-		const char *arg = argv[i];
-		if (arg[0] == '-' && arg[1] != '\0')
-			break;
-		if (strcmp(arg, "(") == 0 || strcmp(arg, "!") == 0)
-			break;
-	}
-
-	return i;
-}
-
 void Bgpgrep_Fatal(const char *fmt, ...)
 {
 	va_list va;
@@ -126,6 +110,46 @@ void Bgpgrep_Warning(const char *fmt, ...)
 	Sys_Print(STDERR, "\n");
 }
 
+static void Bgpgrep_ApplyProgramOptions(void)
+{
+	S.noColor      = options[NO_COLOR_FLAG].flagged;
+	S.dumpBytecode = options[DUMP_BYTECODE_FLAG].flagged;
+	if (options[OUTPUT_FLAG].flagged) {
+		const char *filename = options[OUTPUT_FLAG].optarg;
+
+		Fildes fd = Sys_Fopen(filename, FM_WRITE, /*hints=*/0);
+		if (fd == FILDES_BAD)
+			Bgpgrep_Fatal("Can't open output file \"%s\"", filename);
+
+		S.outf    = STM_FILDES(fd);
+		S.outfOps = Stm_FildesOps;
+
+		S.noColor = TRUE;
+	} else {
+		S.outf    = STM_CONHN(STDOUT);
+		S.outfOps = Stm_ConOps;
+	}
+	if (!S.noColor && Sys_IsVt100Console(STDOUT))
+		S.outFmt = Bgp_IsolarioFmtWc;  // console supports colors
+	else
+		S.outFmt = Bgp_IsolarioFmt;
+}
+
+static int CountFileArguments(int argc, char **argv)
+{
+	int i;
+
+	for (i = 0; i < argc; i++) {
+		const char *arg = argv[i];
+		if (arg[0] == '-' && arg[1] != '\0')
+			break;
+		if (strcmp(arg, "(") == 0 || strcmp(arg, "!") == 0)
+			break;
+	}
+
+	return i;
+}
+
 void Bgpgrep_DropMessage(const char *fmt, ...)
 {
 	va_list va;
@@ -278,11 +302,6 @@ NOINLINE static void Bgpgrep_HandleBgpError(BgpRet err, Srcloc *loc, void *obj)
 
 static void Bgpgrep_Init(void)
 {
-	if (!S.noColor && Sys_IsVt100Console(STDOUT))
-		S.outFmt = Bgp_IsolarioFmtWc;  // console supports colors
-	else
-		S.outFmt = Bgp_IsolarioFmt;
-
 	Mrtrecord *rec = &S.rec;
 	Bgpmsg    *msg = &S.msg;
 
@@ -389,6 +408,9 @@ static int Bgpgrep_CleanupAndExit(void)
 
 		t = tn;
 	}
+
+	if (S.outfOps->Close) S.outfOps->Close(S.outf);
+
 	return (S.nerrors > 0) ? EXIT_FAILURE : EXIT_SUCCESS;
 }
 

tools/bgpgrep/bgpgrep_dump.c

@@ -68,7 +68,7 @@ static void FixBgpAttributeTableForRib(Bgpattrtab tab, Boolean isRibv2)
 static void OutputBgp4mp(const Mrthdr *hdr, Bgpattrtab tab)
 {
 	S.lenientBgpErrors = TRUE;
-	S.outFmt->DumpBgp4mp(hdr, STM_CONHN(STDOUT), Stm_ConOps, tab);
+	S.outFmt->DumpBgp4mp(hdr, S.outf, S.outfOps, tab);
 	S.lenientBgpErrors = FALSE;
 }
 
@@ -104,7 +104,7 @@ void BgpgrepD_Bgp4mp(void)
 static void OutputZebra(const Mrthdr *hdr, Bgpattrtab tab)
 {
 	S.lenientBgpErrors = TRUE;
-	S.outFmt->DumpZebra(hdr, STM_CONHN(STDOUT), Stm_ConOps, tab);
+	S.outFmt->DumpZebra(hdr, S.outf, S.outfOps, tab);
 	S.lenientBgpErrors = FALSE;
 }
 
@@ -149,7 +149,7 @@ static void OutputRibv2(const Mrthdr       *hdr,
                         Bgpattrtab          tab)
 {
 	S.lenientBgpErrors = TRUE;
-	S.outFmt->DumpRibv2(hdr, peerent, ent, STM_CONHN(STDOUT), Stm_ConOps, tab);
+	S.outFmt->DumpRibv2(hdr, peerent, ent, S.outf, S.outfOps, tab);
 	S.lenientBgpErrors = FALSE;
 }
 
@@ -219,7 +219,7 @@ void BgpgrepD_TableDumpv2(void)
 static void OutputRib(const Mrthdr *hdr, const Mrtribent *ent, Bgpattrtab tab)
 {
 	S.lenientBgpErrors = TRUE;
-	S.outFmt->DumpRib(hdr, ent, STM_CONHN(STDOUT), Stm_ConOps, tab);
+	S.outFmt->DumpRib(hdr, ent, S.outf, S.outfOps, tab);
 	S.lenientBgpErrors = FALSE;
 }
 

tools/bgpgrep/bgpgrep_local.h

@@ -104,12 +104,15 @@ typedef jmp_buf frame_buf;
 
 typedef struct BgpgrepState BgpgrepState;
 struct BgpgrepState {
-	const char       *filename;  // current file being processed
+	// Output
 	const BgpDumpfmt *outFmt;
+	void             *outf;
+	const StmOps     *outfOps;
 
 	// MRT input file stream
-	void *inf;             // NOTE: may be NULL even in a file is open
+	const char   *filename;  // current file being processed
-	const StmOps *infOps;  // if NULL no file is open
+	void         *inf;       // NOTE: may be NULL even in a file is open
+	const StmOps *infOps;    // if NULL no file is open
 
 	// Miscellaneous global flags and data
 	Boolean8  noColor;