Remove arbitrary line length limits in pg_regress (plain and ECPG).

Refactor replace_string() to use a StringInfo for the modifiable
string argument.  This allows the string to be of indefinite size
initially and/or grow substantially during replacement.  The previous
logic in convert_sourcefiles_in() had a hard-wired limit of 1024
bytes on any line in input/*.sql or output/*.out files.  While we've
not had reports of trouble yet, it'd surely have bit us someday.

This also fixes replace_string() so it won't get into an infinite
loop if the string-to-be-replaced is a substring of the replacement.
That's unlikely to happen in current usage, but the function surely
shouldn't depend on it.

Also fix ecpg_filter() to use a StringInfo and thereby remove its
hard limit of 300 bytes on the length of an ecpg source line.

Asim Rama Praveen and Georgios Kokolatos,
reviewed by Alvaro Herrera and myself

Discussion: https://postgr.es/m/y9Dlk2QhiZ39DhaB1QE9mgZ95HcOQKZCNtGwN7XCRKMdBRBnX_0woaRUtTjloEp4PKA6ERmcUcfq3lPGfKPOJ5xX2TV-5WoRYyySeNHRzdw=@protonmail.com

src/interfaces/ecpg/test/pg_regress_ecpg.c

@@ -19,8 +19,9 @@
 #include "postgres_fe.h"
 
 #include "pg_regress.h"
+#include "common/string.h"
+#include "lib/stringinfo.h"
 
-#define LINEBUFSIZE 300
 
 static void
 ecpg_filter(const char *sourcefile, const char *outfile)
@@ -31,7 +32,7 @@ ecpg_filter(const char *sourcefile, const char *outfile)
 	 */
 	FILE	   *s,
 			   *t;
-	char		linebuf[LINEBUFSIZE];
+	StringInfoData linebuf;
 
 	s = fopen(sourcefile, "r");
 	if (!s)
@@ -46,13 +47,14 @@ ecpg_filter(const char *sourcefile, const char *outfile)
 		exit(2);
 	}
 
-	while (fgets(linebuf, LINEBUFSIZE, s))
+	initStringInfo(&linebuf);
+
+	while (pg_get_line_append(s, &linebuf))
 	{
 		/* check for "#line " in the beginning */
-		if (strstr(linebuf, "#line ") == linebuf)
+		if (strstr(linebuf.data, "#line ") == linebuf.data)
 		{
-			char	   *p = strchr(linebuf, '"');
-			char	   *n;
+			char	   *p = strchr(linebuf.data, '"');
 			int			plen = 1;
 
 			while (*p && (*(p + plen) == '.' || strchr(p + plen, '/') != NULL))
@@ -62,13 +64,15 @@ ecpg_filter(const char *sourcefile, const char *outfile)
 			/* plen is one more than the number of . and / characters */
 			if (plen > 1)
 			{
-				n = (char *) malloc(plen);
-				strlcpy(n, p + 1, plen);
-				replace_string(linebuf, n, "");
+				memmove(p + 1, p + plen, strlen(p + plen) + 1);
+				/* we don't bother to fix up linebuf.len */
 			}
 		}
-		fputs(linebuf, t);
+		fputs(linebuf.data, t);
+		resetStringInfo(&linebuf);
 	}
+
+	pfree(linebuf.data);
 	fclose(s);
 	fclose(t);
 }
@@ -87,40 +91,42 @@ ecpg_start_test(const char *testname,
 	PID_TYPE	pid;
 	char		inprg[MAXPGPATH];
 	char		insource[MAXPGPATH];
-	char	   *outfile_stdout,
+	StringInfoData testname_dash;
+	char		outfile_stdout[MAXPGPATH],
 				expectfile_stdout[MAXPGPATH];
-	char	   *outfile_stderr,
+	char		outfile_stderr[MAXPGPATH],
 				expectfile_stderr[MAXPGPATH];
-	char	   *outfile_source,
+	char		outfile_source[MAXPGPATH],
 				expectfile_source[MAXPGPATH];
 	char		cmd[MAXPGPATH * 3];
-	char	   *testname_dash;
 	char	   *appnameenv;
 
 	snprintf(inprg, sizeof(inprg), "%s/%s", inputdir, testname);
+	snprintf(insource, sizeof(insource), "%s.c", testname);
+
+	initStringInfo(&testname_dash);
+	appendStringInfoString(&testname_dash, testname);
+	replace_string(&testname_dash, "/", "-");
 
-	testname_dash = strdup(testname);
-	replace_string(testname_dash, "/", "-");
 	snprintf(expectfile_stdout, sizeof(expectfile_stdout),
 			 "%s/expected/%s.stdout",
-			 outputdir, testname_dash);
+			 outputdir, testname_dash.data);
 	snprintf(expectfile_stderr, sizeof(expectfile_stderr),
 			 "%s/expected/%s.stderr",
-			 outputdir, testname_dash);
+			 outputdir, testname_dash.data);
 	snprintf(expectfile_source, sizeof(expectfile_source),
 			 "%s/expected/%s.c",
-			 outputdir, testname_dash);
-
-	/*
-	 * We can use replace_string() here because the replacement string does
-	 * not occupy more space than the replaced one.
-	 */
-	outfile_stdout = strdup(expectfile_stdout);
-	replace_string(outfile_stdout, "/expected/", "/results/");
-	outfile_stderr = strdup(expectfile_stderr);
-	replace_string(outfile_stderr, "/expected/", "/results/");
-	outfile_source = strdup(expectfile_source);
-	replace_string(outfile_source, "/expected/", "/results/");
+			 outputdir, testname_dash.data);
+
+	snprintf(outfile_stdout, sizeof(outfile_stdout),
+			 "%s/results/%s.stdout",
+			 outputdir, testname_dash.data);
+	snprintf(outfile_stderr, sizeof(outfile_stderr),
+			 "%s/results/%s.stderr",
+			 outputdir, testname_dash.data);
+	snprintf(outfile_source, sizeof(outfile_source),
+			 "%s/results/%s.c",
+			 outputdir, testname_dash.data);
 
 	add_stringlist_item(resultfiles, outfile_stdout);
 	add_stringlist_item(expectfiles, expectfile_stdout);
@@ -134,18 +140,15 @@ ecpg_start_test(const char *testname,
 	add_stringlist_item(expectfiles, expectfile_source);
 	add_stringlist_item(tags, "source");
 
-	snprintf(insource, sizeof(insource), "%s.c", testname);
 	ecpg_filter(insource, outfile_source);
 
-	snprintf(inprg, sizeof(inprg), "%s/%s", inputdir, testname);
-
 	snprintf(cmd, sizeof(cmd),
 			 "\"%s\" >\"%s\" 2>\"%s\"",
 			 inprg,
 			 outfile_stdout,
 			 outfile_stderr);
 
-	appnameenv = psprintf("PGAPPNAME=ecpg/%s", testname_dash);
+	appnameenv = psprintf("PGAPPNAME=ecpg/%s", testname_dash.data);
 	putenv(appnameenv);
 
 	pid = spawn_process(cmd);
@@ -160,10 +163,7 @@ ecpg_start_test(const char *testname,
 	unsetenv("PGAPPNAME");
 	free(appnameenv);
 
-	free(testname_dash);
-	free(outfile_stdout);
-	free(outfile_stderr);
-	free(outfile_source);
+	free(testname_dash.data);
 
 	return pid;
 }

src/test/regress/pg_regress.c

@@ -31,8 +31,10 @@
 
 #include "common/logging.h"
 #include "common/restricted_token.h"
+#include "common/string.h"
 #include "common/username.h"
 #include "getopt_long.h"
+#include "lib/stringinfo.h"
 #include "libpq/pqcomm.h"		/* needed for UNIXSOCK_PATH() */
 #include "pg_config_paths.h"
 #include "pg_regress.h"
@@ -435,22 +437,32 @@ string_matches_pattern(const char *str, const char *pattern)
 }
 
 /*
- * Replace all occurrences of a string in a string with a different string.
- * NOTE: Assumes there is enough room in the target buffer!
+ * Replace all occurrences of "replace" in "string" with "replacement".
+ * The StringInfo will be suitably enlarged if necessary.
+ *
+ * Note: this is optimized on the assumption that most calls will find
+ * no more than one occurrence of "replace", and quite likely none.
  */
 void
-replace_string(char *string, const char *replace, const char *replacement)
+replace_string(StringInfo string, const char *replace, const char *replacement)
 {
+	int			pos = 0;
 	char	   *ptr;
 
-	while ((ptr = strstr(string, replace)) != NULL)
+	while ((ptr = strstr(string->data + pos, replace)) != NULL)
 	{
-		char	   *dup = pg_strdup(string);
+		/* Must copy the remainder of the string out of the StringInfo */
+		char	   *suffix = pg_strdup(ptr + strlen(replace));
 
-		strlcpy(string, dup, ptr - string + 1);
-		strcat(string, replacement);
-		strcat(string, dup + (ptr - string) + strlen(replace));
-		free(dup);
+		/* Truncate StringInfo at start of found string ... */
+		string->len = ptr - string->data;
+		/* ... and append the replacement (this restores the trailing '\0') */
+		appendStringInfoString(string, replacement);
+		/* Next search should start after the replacement */
+		pos = string->len;
+		/* Put back the remainder of the string */
+		appendStringInfoString(string, suffix);
+		free(suffix);
 	}
 }
 
@@ -521,7 +533,7 @@ convert_sourcefiles_in(const char *source_subdir, const char *dest_dir, const ch
 		char		prefix[MAXPGPATH];
 		FILE	   *infile,
 				   *outfile;
-		char		line[1024];
+		StringInfoData line;
 
 		/* reject filenames not finishing in ".source" */
 		if (strlen(*name) < 8)
@@ -551,15 +563,21 @@ convert_sourcefiles_in(const char *source_subdir, const char *dest_dir, const ch
 					progname, destfile, strerror(errno));
 			exit(2);
 		}
-		while (fgets(line, sizeof(line), infile))
+
+		initStringInfo(&line);
+
+		while (pg_get_line_append(infile, &line))
 		{
-			replace_string(line, "@abs_srcdir@", inputdir);
-			replace_string(line, "@abs_builddir@", outputdir);
-			replace_string(line, "@testtablespace@", testtablespace);
-			replace_string(line, "@libdir@", dlpath);
-			replace_string(line, "@DLSUFFIX@", DLSUFFIX);
-			fputs(line, outfile);
+			replace_string(&line, "@abs_srcdir@", inputdir);
+			replace_string(&line, "@abs_builddir@", outputdir);
+			replace_string(&line, "@testtablespace@", testtablespace);
+			replace_string(&line, "@libdir@", dlpath);
+			replace_string(&line, "@DLSUFFIX@", DLSUFFIX);
+			fputs(line.data, outfile);
+			resetStringInfo(&line);
 		}
+
+		pfree(line.data);
 		fclose(infile);
 		fclose(outfile);
 	}

src/test/regress/pg_regress.h

@@ -18,6 +18,8 @@
 #define INVALID_PID INVALID_HANDLE_VALUE
 #endif
 
+struct StringInfoData;			/* avoid including stringinfo.h here */
+
 /* simple list of strings */
 typedef struct _stringlist
 {
@@ -49,5 +51,6 @@ int			regression_main(int argc, char *argv[],
 							init_function ifunc, test_function tfunc);
 void		add_stringlist_item(_stringlist **listhead, const char *str);
 PID_TYPE	spawn_process(const char *cmdline);
-void		replace_string(char *string, const char *replace, const char *replacement);
+void		replace_string(struct StringInfoData *string,
+						   const char *replace, const char *replacement);
 bool		file_exists(const char *file);