Fixed a compatibility problem is some file functions (fgets, fputs, fread,

fwrite). The ANSI standard says that if a file is opened in read/write
mode, fseek() should be called before switching from reading to writing
and vice versa.

3 files changed, 72 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index fdad917b50..77002037fd 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,10 @@ PHP 4.0                                                                    NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 
 ?? ??? 200?, Version 4.0.5
+- Fixed a compatibility problem in some file functions (fgets, fputs, fread,
+  fwrite). The ANSI standard says that if a file is opened in read/write
+  mode, fseek() should be called before switching from reading to writing
+  and vice versa. (alex@zend.com)
 - Fixed argument checking for call_user_func* functions and allowed
   specifying array($obj, 'method') syntax for call_user_func_array. (Andrei)
 - Fixed parent::method() to also work with runtime bindings (Zeev, Zend Engine)
diff --git a/ext/standard/config.m4 b/ext/standard/config.m4
index 9752ba0d42..d1c7cfd5a0 100644
--- a/ext/standard/config.m4
+++ b/ext/standard/config.m4
@@ -3,6 +3,57 @@ dnl $Id$ -*- sh -*-
 divert(3)dnl
 
 dnl
+dnl Check if flush should be called explicitly after buffered io
+dnl
+AC_DEFUN(AC_FLUSH_IO,[
+  AC_CACHE_CHECK([whether flush should be called explicitly after a bufferered io], ac_cv_flush_io,[
+  AC_TRY_RUN( [
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv)
+{
+	char *filename = tmpnam(NULL);
+	char buffer[64];
+	int result = 0;
+	
+	FILE *fp = fopen(filename, "wb");
+	if (NULL == fp)
+		return 0;
+	fputs("line 1\n", fp);
+	fputs("line 2\n", fp);
+	fclose(fp);
+	
+	fp = fopen(filename, "rb+");
+	if (NULL == fp)
+		return 0;
+	fgets(buffer, sizeof(buffer), fp);
+	fputs("line 3\n", fp);
+	rewind(fp);
+	fgets(buffer, sizeof(buffer), fp);
+	if (0 != strcmp(buffer, "line 1\n"))
+		result = 1;
+	fgets(buffer, sizeof(buffer), fp);
+	if (0 != strcmp(buffer, "line 3\n"))
+		result = 1;
+	fclose(fp);
+	unlink(filename);
+
+	exit(result);
+}
+],[
+  ac_cv_flush_io="no"
+],[
+  ac_cv_flush_io="yes"
+],[
+  ac_cv_flush_io="no"
+])])
+  if test "$ac_cv_flush_io" = "yes"; then
+    AC_DEFINE(HAVE_FLUSHIO, 1, [Define if flush should be called explicitly after a buffered io.])
+  fi
+])
+
+dnl
 dnl Check for crypt() capabilities
 dnl
 AC_DEFUN(AC_CRYPT_CAP,[
@@ -143,6 +194,7 @@ AC_CHECK_LIB(pam, pam_start, [
 AC_CHECK_FUNCS(getcwd getwd)
 
 AC_CRYPT_CAP
+AC_FLUSH_IO
 
 divert(5)dnl
 
diff --git a/ext/standard/file.c b/ext/standard/file.c
index b1500e37d8..2808d41a6b 100644
--- a/ext/standard/file.c
+++ b/ext/standard/file.c
@@ -918,6 +918,11 @@ PHP_FUNCTION(fgets)
 	buf = emalloc(sizeof(char) * (len + 1));
 	/* needed because recv doesnt put a null at the end*/
 	memset(buf,0,len+1);
+#ifdef HAVE_FLUSHIO
+	if (!issock) {
+		fseek((FILE*)what, 0, SEEK_CUR);
+	}
+#endif
 	if (FP_FGETS(buf, len, socketd, (FILE*)what, issock) == NULL) {
 		efree(buf);
 		RETVAL_FALSE;
@@ -961,6 +966,11 @@ PHP_FUNCTION(fgetc) {
 		socketd=*(int*)what;
 	}
 
+#ifdef HAVE_FLUSHIO
+	if (!issock) {
+		fseek((FILE*)what, 0, SEEK_CUR);
+	}
+#endif
 	buf = emalloc(sizeof(int));
 	if ((result = FP_FGETC(socketd, (FILE*)what, issock)) == EOF) {
 		efree(buf);
@@ -1159,6 +1169,9 @@ PHP_FUNCTION(fwrite)
 	if (issock){
 		ret = SOCK_WRITEL((*arg2)->value.str.val,num_bytes,socketd);
 	} else {
+#ifdef HAVE_FLUSHIO
+		fseek((FILE*)what, 0, SEEK_CUR);
+#endif
 		ret = fwrite((*arg2)->value.str.val,1,num_bytes,(FILE*)what);
 	}
 	RETURN_LONG(ret);
@@ -1794,6 +1807,9 @@ PHP_FUNCTION(fread)
 	/* needed because recv doesnt put a null at the end*/
 	
 	if (!issock) {
+#ifdef HAVE_FLUSHIO
+		fseek((FILE*)what, 0, SEEK_CUR);
+#endif
 		return_value->value.str.len = fread(return_value->value.str.val, 1, len, (FILE*)what);
 		return_value->value.str.val[return_value->value.str.len] = 0;
 	} else {