File fix-fgets-.-size-1.patch of Package unifdef.29781

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File fix-fgets-.-size-1.patch of Package unifdef.29781

From 9791614057fe7fc72babd78708fdd07857fef9cf Mon Sep 17 00:00:00 2001
From: Martin Liska <mliska@suse.cz>
Date: Wed, 10 Aug 2022 10:06:55 +0200
Subject: [PATCH] Fix fgets(..., size=1)

I noticed the following 2 tests are failing with -O1
-D_FORTIFY_SOURCE=1:

[   44s] FAILED: whitespace-1.out: unifdef -DFOO whitespace.c
[   44s] FAILED: whitespace-2.out: unifdef -DBAR whitespace.c

It's caused by fact that:

fgets returns '\0' if n == 1:

char *
_IO_fgets (char *buf, int n, FILE *fp)
{
  size_t count;
  char *result;
  int old_error;
  CHECK_FILE (fp, NULL);
  if (n <= 0)
    return NULL;
  if (__glibc_unlikely (n == 1))
    {
      /* Another irregular case: since we have to store a NUL byte and
	 there is only room for exactly one byte, we don't have to
	 read anything.  */
      buf[0] = '\0';
      return buf;
    }
---
 tests/whitespace-1.experr | 2 --
 tests/whitespace-1.expout | 5 +++++
 tests/whitespace-1.exprc  | 2 +-
 tests/whitespace-2.expout | 3 ++-
 unifdef.c                 | 3 ++-
 5 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/tests/whitespace-1.experr b/tests/whitespace-1.experr
index cb23fce..e69de29 100644
--- a/tests/whitespace-1.experr
+++ b/tests/whitespace-1.experr
@@ -1,2 +0,0 @@
-unifdef: whitespace.c: 4: Obfuscated preprocessor control line (#if line 1 depth 1)
-unifdef: Output may be truncated
diff --git a/tests/whitespace-1.expout b/tests/whitespace-1.expout
index 257cc56..14dd150 100644
--- a/tests/whitespace-1.expout
+++ b/tests/whitespace-1.expout
@@ -1 +1,6 @@
 foo
+                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               //spong
+
+#ifdef BAR
+bar
+#endif
diff --git a/tests/whitespace-1.exprc b/tests/whitespace-1.exprc
index 0cfbf08..d00491f 100644
--- a/tests/whitespace-1.exprc
+++ b/tests/whitespace-1.exprc
@@ -1 +1 @@
-2
+1
diff --git a/tests/whitespace-2.expout b/tests/whitespace-2.expout
index 84cabfe..43f6399 100644
--- a/tests/whitespace-2.expout
+++ b/tests/whitespace-2.expout
@@ -1,5 +1,6 @@
 #ifdef FOO
 foo
-#endif                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        //spong
+#endif                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
+                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               //spong
 
 bar
diff --git a/unifdef.c b/unifdef.c
index dc145a2..b7335aa 100644
--- a/unifdef.c
+++ b/unifdef.c
@@ -846,7 +846,8 @@ parseline(void)
 	   newline or if there is too much whitespace in a directive */
 	if (linestate == LS_HASH) {
 		long len = cp - tline;
-		if (fgets(tline + len, MAXLINE - len, input) == NULL) {
+		const char *line = fgets(tline + len, MAXLINE - len, input);
+		if (line == NULL || *line == '\0') {
 			if (ferror(input))
 				err(2, "can't read %s", filename);
 			debug("parser insert newline at EOF", linenum);
-- 
2.37.1

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File fix-fgets-.-size-1.patch of Package unifdef.29781

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