git/builtin/get-tar-commit-id.c
Jeff King 41dcc4dccc distinguish error versus short read from read_in_full()
Many callers of read_in_full() expect to see the exact
number of bytes requested, but their error handling lumps
together true read errors and short reads due to unexpected
EOF.

We can give more specific error messages by separating these
cases (showing errno when appropriate, and otherwise
describing the short read).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-27 15:45:24 +09:00

43 lines
1.0 KiB
C

/*
* Copyright (c) 2005, 2006 Rene Scharfe
*/
#include "cache.h"
#include "commit.h"
#include "tar.h"
#include "builtin.h"
#include "quote.h"
static const char builtin_get_tar_commit_id_usage[] =
"git get-tar-commit-id";
/* ustar header + extended global header content */
#define RECORDSIZE (512)
#define HEADERSIZE (2 * RECORDSIZE)
int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix)
{
char buffer[HEADERSIZE];
struct ustar_header *header = (struct ustar_header *)buffer;
char *content = buffer + RECORDSIZE;
const char *comment;
ssize_t n;
if (argc != 1)
usage(builtin_get_tar_commit_id_usage);
n = read_in_full(0, buffer, HEADERSIZE);
if (n < 0)
die_errno("git get-tar-commit-id: read error");
if (n != HEADERSIZE)
die_errno("git get-tar-commit-id: EOF before reading tar header");
if (header->typeflag[0] != 'g')
return 1;
if (!skip_prefix(content, "52 comment=", &comment))
return 1;
if (write_in_full(1, comment, 41) < 0)
die_errno("git get-tar-commit-id: write error");
return 0;
}