curl_get_line: allow last line without newline char

improve backwards compatibility

Test 3200 verifies

Closes #9973

lib/curl_get_line.c

@@ -41,17 +41,41 @@ char *Curl_get_line(char *buf, int len, FILE *input)
   bool partial = FALSE;
   while(1) {
     char *b = fgets(buf, len, input);
+
     if(b) {
       size_t rlen = strlen(b);
-      if(rlen && (b[rlen-1] == '\n')) {
+
+      if(!rlen)
+        break;
+
+      if(b[rlen-1] == '\n') {
+        /* b is \n terminated */
         if(partial) {
           partial = FALSE;
           continue;
         }
         return b;
       }
-      /* read a partial, discard the next piece that ends with newline */
-      partial = TRUE;
+      else if(feof(input)) {
+        if(partial)
+          /* Line is already too large to return, ignore rest */
+          break;
+
+        if(rlen + 1 < (size_t) len) {
+          /* b is EOF terminated, insert missing \n */
+          b[rlen] = '\n';
+          b[rlen + 1] = '\0';
+          return b;
+        }
+        else
+          /* Maximum buffersize reached + EOF
+           * This line is impossible to add a \n to so we'll ignore it
+           */
+          break;
+      }
+      else
+        /* Maximum buffersize reached */
+        partial = TRUE;
     }
     else
       break;

tests/data/Makefile.inc

@@ -250,4 +250,5 @@ test3008 test3009 test3010 test3011 test3012 test3013 test3014 test3015 \
 test3016 test3017 test3018 test3019 test3020 test3021 test3022 test3023 \
 test3024 test3025 test3026 test3027 test3028 \
 \
-test3100 test3101
+test3100 test3101 \
+test3200

tests/data/test3200

@@ -0,0 +1,22 @@
+<testcase>
+<info>
+<keywords>
+unittest
+curl_get_line
+</keywords>
+</info>
+
+#
+# Client-side
+<client>
+<server>
+none
+</server>
+<features>
+unittest
+</features>
+ <name>
+curl_get_line unit tests
+ </name>
+</client>
+</testcase>

tests/unit/Makefile.inc

@@ -37,7 +37,8 @@ UNITPROGS = unit1300          unit1302 unit1303 unit1304 unit1305 unit1307 \
  unit1608 unit1609 unit1610 unit1611 unit1612 unit1614 \
  unit1620 unit1621 \
  unit1650 unit1651 unit1652 unit1653 unit1654 unit1655 \
- unit1660 unit1661
+ unit1660 unit1661 \
+ unit3200
 
 unit1300_SOURCES = unit1300.c $(UNITFILES)
 unit1300_CPPFLAGS = $(AM_CPPFLAGS)
@@ -162,3 +163,6 @@ unit1660_CPPFLAGS = $(AM_CPPFLAGS)
 
 unit1661_SOURCES = unit1661.c $(UNITFILES)
 unit1661_CPPFLAGS = $(AM_CPPFLAGS)
+
+unit3200_SOURCES = unit3200.c $(UNITFILES)
+unit3200_CPPFLAGS = $(AM_CPPFLAGS)

tests/unit/unit3200.c

@@ -0,0 +1,164 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ ***************************************************************************/
+#include "curlcheck.h"
+#include "curl_get_line.h"
+
+#define TESTINPUT "log/curl_get_line2101"
+
+/* The test XML does not supply a way to write files without newlines
+ * so we write our own
+ */
+
+#define C64 "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+#define C256 C64 C64 C64 C64
+#define C1024 C256 C256 C256 C256
+#define C4096 C1024 C1024 C1024 C1024
+
+static CURLcode unit_setup(void)
+{
+  return CURLE_OK;
+}
+
+static CURLcode unit_stop(void)
+{
+  return CURLE_OK;
+}
+
+#ifdef __GNUC__
+#pragma GCC diagnostic ignored "-Woverlength-strings"
+#endif
+
+#define NUMTESTS 6
+static const char *filecontents[] = {
+  /* Both should be read */
+  "LINE1\n"
+  "LINE2 NEWLINE\n",
+
+  /* Both should be read */
+  "LINE1\n"
+  "LINE2 NONEWLINE",
+
+  /* Only first should be read */
+  "LINE1\n"
+  C4096,
+
+  /* First line should be read */
+  "LINE1\n"
+  C4096 "SOME EXTRA TEXT",
+
+  /* First and third line should be read */
+  "LINE1\n"
+  C4096 "SOME EXTRA TEXT\n"
+  "LINE3\n",
+
+  "LINE1\x1aTEST"
+};
+
+#ifdef __GNUC__
+#pragma GCC diagnostic warning "-Woverlength-strings"
+#endif
+
+
+UNITTEST_START
+{
+  size_t i;
+  for(i = 0; i < NUMTESTS; i++) {
+    FILE *fp;
+    char buf[4096];
+    int len = 4096;
+    char *line;
+
+    fp = fopen(TESTINPUT, "wb");
+    abort_unless(fp != NULL, "Cannot open testfile");
+    fwrite(filecontents[i], 1, strlen(filecontents[i]), fp);
+    fclose(fp);
+
+    fp = fopen(TESTINPUT, "rb");
+    abort_unless(fp != NULL, "Cannot open testfile");
+
+    fprintf(stderr, "Test %d...", i);
+    switch(i) {
+      case 0:
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE1\n", line),
+          "First line failed (1)");
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE2 NEWLINE\n", line),
+          "Second line failed (1)");
+        line = Curl_get_line(buf, len, fp);
+        abort_unless(line == NULL, "Missed EOF (1)");
+        break;
+      case 1:
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE1\n", line),
+          "First line failed (2)");
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE2 NONEWLINE\n", line),
+          "Second line failed (2)");
+        line = Curl_get_line(buf, len, fp);
+        abort_unless(line == NULL, "Missed EOF (2)");
+        break;
+      case 2:
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE1\n", line),
+          "First line failed (3)");
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line == NULL,
+          "Did not detect max read on EOF (3)");
+        break;
+      case 3:
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE1\n", line),
+          "First line failed (4)");
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line == NULL,
+          "Did not ignore partial on EOF (4)");
+        break;
+      case 4:
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE1\n", line),
+          "First line failed (5)");
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE3\n", line),
+          "Third line failed (5)");
+        line = Curl_get_line(buf, len, fp);
+        abort_unless(line == NULL, "Missed EOF (5)");
+        break;
+      case 5:
+        line = Curl_get_line(buf, len, fp);
+        fail_unless(line && !strcmp("LINE1\x1aTEST\n", line),
+          "Missed/Misinterpreted ^Z (6)");
+        line = Curl_get_line(buf, len, fp);
+        abort_unless(line == NULL, "Missed EOF (6)");
+        break;
+      default:
+        abort_unless(1, "Unknown case");
+        break;
+    }
+    fclose(fp);
+    fprintf(stderr, "OK\n");
+  }
+  return 0;
+}
+UNITTEST_STOP