git/t/helper/test-genzeros.c
Junio C Hamano 58eab6ff13 test-genzeros: avoid raw write(2)
This test helper feeds 256kB of data at once to a single invocation
of the write(2) system call, which may be too much for some
platforms.

Call our xwrite() wrapper that knows to honor MAX_IO_SIZE limit and
cope with short writes due to EINTR instead, and die a bit more
loudly by calling die_errno() when xwrite() indicates an error.

Reported-by: Randall S. Becker <rsbecker@nexbridge.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-02-16 08:30:38 -08:00

35 lines
690 B
C

#include "test-tool.h"
#include "git-compat-util.h"
int cmd__genzeros(int argc, const char **argv)
{
/* static, so that it is NUL-initialized */
static const char zeros[256 * 1024];
intmax_t count;
ssize_t n;
if (argc > 2) {
fprintf(stderr, "usage: %s [<count>]\n", argv[0]);
return 1;
}
count = argc > 1 ? strtoimax(argv[1], NULL, 0) : -1;
/* Writing out individual NUL bytes is slow... */
while (count < 0)
if (xwrite(1, zeros, ARRAY_SIZE(zeros)) < 0)
die_errno("write error");
while (count > 0) {
n = xwrite(1, zeros,
count < ARRAY_SIZE(zeros)
? count : ARRAY_SIZE(zeros));
if (n < 0)
die_errno("write error");
count -= n;
}
return 0;
}