Refactor logic to remove trailing CR/LF characters from strings

b654714 has reworked the way trailing CR/LF characters are removed from
strings.  This commit introduces a new routine in common/string.c and
refactors the code so as the logic is in a single place, mostly.

Author: Michael Paquier
Reviewed-by: Bruce Momjian
Discussion: https://postgr.es/m/20190801031820.GF29334@paquier.xyz

Author: michaelpq

src/backend/libpq/be-secure-common.c

@@ -22,6 +22,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include "common/string.h"
 #include "libpq/libpq.h"
 #include "storage/fd.h"
 
@@ -112,11 +113,8 @@ run_ssl_passphrase_command(const char *prompt, bool is_server_start, char *buf,
 		goto error;
 	}
 
-	/* strip trailing newline, including \r in case we're on Windows */
-	len = strlen(buf);
-	while (len > 0 && (buf[len - 1] == '\n' ||
-					   buf[len - 1] == '\r'))
-		buf[--len] = '\0';
+	/* strip trailing newline and carriage return */
+	len = pg_strip_crlf(buf);
 
 error:
 	pfree(command.data);

src/bin/pg_ctl/pg_ctl.c

@@ -27,6 +27,7 @@
 #include "common/controldata_utils.h"
 #include "common/file_perm.h"
 #include "common/logging.h"
+#include "common/string.h"
 #include "getopt_long.h"
 #include "utils/pidfile.h"
 
@@ -2176,7 +2177,6 @@ adjust_data_dir(void)
 				filename[MAXPGPATH],
 			   *my_exec_path;
 	FILE	   *fd;
-	int			len;
 
 	/* do nothing if we're working without knowledge of data dir */
 	if (pg_config == NULL)
@@ -2219,12 +2219,8 @@ adjust_data_dir(void)
 	pclose(fd);
 	free(my_exec_path);
 
-	/* Remove trailing newline, handling Windows newlines as well */
-	len = strlen(filename);
-	while (len > 0 &&
-		   (filename[len - 1] == '\n' ||
-			filename[len - 1] == '\r'))
-		filename[--len] = '\0';
+	/* strip trailing newline and carriage return */
+	(void) pg_strip_crlf(filename);
 
 	free(pg_data);
 	pg_data = pg_strdup(filename);

src/bin/pg_resetwal/pg_resetwal.c

@@ -54,6 +54,7 @@
 #include "common/file_perm.h"
 #include "common/logging.h"
 #include "common/restricted_token.h"
+#include "common/string.h"
 #include "storage/large_object.h"
 #include "pg_getopt.h"
 #include "getopt_long.h"
@@ -538,7 +539,6 @@ CheckDataVersion(void)
 	const char *ver_file = "PG_VERSION";
 	FILE	   *ver_fd;
 	char		rawline[64];
-	int			len;
 
 	if ((ver_fd = fopen(ver_file, "r")) == NULL)
 	{
@@ -557,12 +557,8 @@ CheckDataVersion(void)
 		exit(1);
 	}
 
-	/* remove trailing newline, handling Windows newlines as well */
-	len = strlen(rawline);
-	while (len > 0 &&
-		   (rawline[len - 1] == '\n' ||
-			rawline[len - 1] == '\r'))
-		rawline[--len] = '\0';
+	/* strip trailing newline and carriage return */
+	(void) pg_strip_crlf(rawline);
 
 	if (strcmp(rawline, PG_MAJORVERSION) != 0)
 	{

src/bin/pg_upgrade/option.c

@@ -15,6 +15,7 @@
 #endif
 
 #include "getopt_long.h"
+#include "common/string.h"
 #include "utils/pidfile.h"
 
 #include "pg_upgrade.h"
@@ -411,7 +412,6 @@ adjust_data_dir(ClusterInfo *cluster)
 				cmd_output[MAX_STRING];
 	FILE	   *fp,
 			   *output;
-	int			len;
 
 	/* Initially assume config dir and data dir are the same */
 	cluster->pgconfig = pg_strdup(cluster->pgdata);
@@ -452,12 +452,8 @@ adjust_data_dir(ClusterInfo *cluster)
 
 	pclose(output);
 
-	/* Remove trailing newline, handling Windows newlines as well */
-	len = strlen(cmd_output);
-	while (len > 0 &&
-		   (cmd_output[len - 1] == '\n' ||
-			cmd_output[len - 1] == '\r'))
-		cmd_output[--len] = '\0';
+	/* strip trailing newline and carriage return */
+	(void) pg_strip_crlf(cmd_output);
 
 	cluster->pgdata = pg_strdup(cmd_output);
 
@@ -518,15 +514,9 @@ get_sock_dir(ClusterInfo *cluster, bool live_check)
 					sscanf(line, "%hu", &old_cluster.port);
 				if (lineno == LOCK_FILE_LINE_SOCKET_DIR)
 				{
-					int			len;
-
+					/* strip trailing newline and carriage return */
 					cluster->sockdir = pg_strdup(line);
-					/* strip off newline, handling Windows newlines as well */
-					len = strlen(cluster->sockdir);
-					while (len > 0 &&
-						   (cluster->sockdir[len - 1] == '\n' ||
-							cluster->sockdir[len - 1] == '\r'))
-						cluster->sockdir[--len] = '\0';
+					(void) pg_strip_crlf(cluster->sockdir);
 				}
 			}
 			fclose(fp);

src/bin/psql/prompt.c

@@ -22,6 +22,7 @@
 #include "prompt.h"
 #include "settings.h"
 
+#include "common/string.h"
 
 /*--------------------------
  * get_prompt
@@ -264,7 +265,6 @@ get_prompt(promptStatus_t status, ConditionalStack cstack)
 						FILE	   *fd;
 						char	   *file = pg_strdup(p + 1);
 						int			cmdend;
-						int			buflen;
 
 						cmdend = strcspn(file, "`");
 						file[cmdend] = '\0';
@@ -275,10 +275,10 @@ get_prompt(promptStatus_t status, ConditionalStack cstack)
 								buf[0] = '\0';
 							pclose(fd);
 						}
-						buflen = strlen(buf);
-						while (buflen > 0 && (buf[buflen - 1] == '\n' ||
-											  buf[buflen - 1] == '\r'))
-							buf[--buflen] = '\0';
+
+						/* strip trailing newline and carriage return */
+						(void) pg_strip_crlf(buf);
+
 						free(file);
 						p += cmdend + 1;
 						break;

src/common/string.c

@@ -90,3 +90,25 @@ pg_clean_ascii(char *str)
 			*p = '?';
 	}
 }
+
+
+/*
+ * pg_strip_crlf -- Remove any trailing newline and carriage return
+ *
+ * Removes any trailing newline and carriage return characters (\r on
+ * Windows) in the input string, zero-terminating it.
+ *
+ * The passed in string must be zero-terminated.  This function returns
+ * the new length of the string.
+ */
+int
+pg_strip_crlf(char *str)
+{
+	int			len = strlen(str);
+
+	while (len > 0 && (str[len - 1] == '\n' ||
+					   str[len - 1] == '\r'))
+		str[--len] = '\0';
+
+	return len;
+}

src/include/common/string.h

@@ -14,5 +14,6 @@ extern bool pg_str_endswith(const char *str, const char *end);
 extern int	strtoint(const char *pg_restrict str, char **pg_restrict endptr,
 					 int base);
 extern void pg_clean_ascii(char *str);
+extern int	pg_strip_crlf(char *str);
 
 #endif							/* COMMON_STRING_H */

src/interfaces/libpq/fe-connect.c

@@ -73,6 +73,7 @@ static int	ldapServiceLookup(const char *purl, PQconninfoOption *options,
 #include "common/ip.h"
 #include "common/link-canary.h"
 #include "common/scram-common.h"
+#include "common/string.h"
 #include "mb/pg_wchar.h"
 #include "port/pg_bswap.h"
 
@@ -6911,12 +6912,8 @@ passwordFromFile(const char *hostname, const char *port, const char *dbname,
 		if (fgets(buf, sizeof(buf), fp) == NULL)
 			break;
 
-		len = strlen(buf);
-
-		/* Remove trailing newline, including \r in case we're on Windows */
-		while (len > 0 && (buf[len - 1] == '\n' ||
-						   buf[len - 1] == '\r'))
-			buf[--len] = '\0';
+		/* strip trailing newline and carriage return */
+		len = pg_strip_crlf(buf);
 
 		if (len == 0)
 			continue;