Re: [PATCH] git-log: detect dup and fdopen failure

[Jim Meyering <jim@meyering.net>]

Geert Bosch <bosch@adacore.com> wrote:
> If we really case about catching such errors, write
> the code as:
> 	if (!use_stdout)
> 		realstdout = xfdopen(dup(1), "w");

Thanks for the suggestion.
Here's a patch doing just that (and same for dup/xdup):

Subject: [PATCH] git-log: detect dup and fdopen failure
 git-compat-util.h (xdup, xfdopen): Define functions.


Signed-off-by: Jim Meyering <jim@meyering.net>
---
 builtin-log.c     |    2 +-
 git-compat-util.h |   16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/builtin-log.c b/builtin-log.c
index 073a2a1..a4186ea 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -589,7 +589,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		get_patch_ids(&rev, &ids, prefix);

 	if (!use_stdout)
-		realstdout = fdopen(dup(1), "w");
+		realstdout = xfdopen(xdup(1), "w");

 	prepare_revision_walk(&rev);
 	while ((commit = get_revision(&rev)) != NULL) {
diff --git a/git-compat-util.h b/git-compat-util.h
index b2ab3f8..362e040 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -287,6 +287,22 @@ static inline ssize_t xwrite(int fd, const void *buf, size_t len)
 	}
 }

+static inline int xdup(int fd)
+{
+	int ret = dup(fd);
+	if (ret < 0)
+		die("dup failed: %s", strerror(errno));
+	return ret;
+}
+
+static inline FILE *xfdopen(int fd, const char *mode)
+{
+	FILE *stream = fdopen(fd, mode);
+	if (stream == NULL)
+		die("Out of memory? fdopen failed: %s", strerror(errno));
+	return stream;
+}
+
 static inline size_t xsize_t(off_t len)
 {
 	return (size_t)len;