This patch fixes corner case in open_memstrem, when stream is created, but nothing is written. This case is present in tgtadm, tgtd management tool. Signed-off-by: Maxim Storchak <m.storchak@gmail.com> SVN-Revision: 47339
		
			
				
	
	
		
			80 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			80 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From 7b9f57f207b51132f188f750161953b7baf32154 Mon Sep 17 00:00:00 2001
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From: Rich Felker <dalias@aerifal.cx>
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Date: Thu, 8 Oct 2015 22:03:53 +0000
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Subject: fix open_[w]memstream behavior when no writes take place
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the specification for these functions requires that the buffer/size
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exposed to the caller be valid after any successful call to fflush or
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fclose on the stream. the implementation's approach is to update them
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only at flush time, but that misses the case where fflush or fclose is
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called without any writes having taken place, in which case the write
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flushing callback will not be called.
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to fix both the observable bug and the desired invariant, setup empty
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buffers at open time and fail the open operation if no memory is
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available.
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---
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 src/stdio/open_memstream.c  | 11 +++++++++--
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 src/stdio/open_wmemstream.c | 11 +++++++++--
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 2 files changed, 18 insertions(+), 4 deletions(-)
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diff --git a/src/stdio/open_memstream.c b/src/stdio/open_memstream.c
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index 58504c9..eab024d 100644
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--- a/src/stdio/open_memstream.c
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+++ b/src/stdio/open_memstream.c
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@@ -59,14 +59,21 @@ FILE *open_memstream(char **bufp, size_t *sizep)
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 {
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 	FILE *f;
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 	struct cookie *c;
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+	char *buf;
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+
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 	if (!(f=malloc(sizeof *f + sizeof *c + BUFSIZ))) return 0;
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+	if (!(buf=malloc(sizeof *buf))) {
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+		free(f);
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+		return 0;
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+	}
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 	memset(f, 0, sizeof *f + sizeof *c);
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 	f->cookie = c = (void *)(f+1);
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 	c->bufp = bufp;
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 	c->sizep = sizep;
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-	c->pos = c->len = c->space = 0;
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-	c->buf = 0;
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+	c->pos = c->len = c->space = *sizep = 0;
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+	c->buf = *bufp = buf;
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+	*buf = 0;
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 	f->flags = F_NORD;
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 	f->fd = -1;
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diff --git a/src/stdio/open_wmemstream.c b/src/stdio/open_wmemstream.c
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index 7ab2c64..4d90cd9 100644
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--- a/src/stdio/open_wmemstream.c
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+++ b/src/stdio/open_wmemstream.c
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@@ -61,14 +61,21 @@ FILE *open_wmemstream(wchar_t **bufp, size_t *sizep)
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 {
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 	FILE *f;
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 	struct cookie *c;
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+	wchar_t *buf;
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+
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 	if (!(f=malloc(sizeof *f + sizeof *c))) return 0;
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+	if (!(buf=malloc(sizeof *buf))) {
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+		free(f);
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+		return 0;
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+	}
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 	memset(f, 0, sizeof *f + sizeof *c);
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 	f->cookie = c = (void *)(f+1);
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 	c->bufp = bufp;
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 	c->sizep = sizep;
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-	c->pos = c->len = c->space = 0;
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-	c->buf = 0;
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+	c->pos = c->len = c->space = *sizep = 0;
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+	c->buf = *bufp = buf;
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+	*buf = 0;
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 	f->flags = F_NORD;
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 	f->fd = -1;
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-- 
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cgit v0.11.2
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