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Don't use buffered IO (fread) when not appropriate

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fread reads the entire requested size (BUFSIZ), which causes tools to
block if only small amounts of data are available at a time. At best,
this causes unnecessary copies and inefficiency, at worst, tools like
tee and cat are almost unusable in some cases since they only display
large chunks of data at a time.
This commit is contained in:
Michael Forney
2017-01-01 17:00:33 -08:00
committed by Anselm R Garbe
parent 5cb3a1eba1
commit 9a3b12525b
5 changed files with 83 additions and 69 deletions
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37
libutil/crypt.c
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@@ -1,8 +1,10 @@
/* See LICENSE file for copyright and license details. */
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "../crypt.h"
#include "../text.h"
@@ -41,7 +43,7 @@ static void
mdchecklist(FILE *listfp, struct crypt_ops *ops, uint8_t *md, size_t sz,
int *formatsucks, int *noread, int *nonmatch)
{
FILE *fp;
int fd;
size_t bufsiz = 0;
int r;
char *line = NULL, *file, *p;
@@ -59,12 +61,12 @@ mdchecklist(FILE *listfp, struct crypt_ops *ops, uint8_t *md, size_t sz,
file += 2;
for (p = file; *p && *p != '\n' && *p != '\r'; p++); /* strip newline */
*p = '\0';
if (!(fp = fopen(file, "r"))) {
weprintf("fopen %s:", file);
if ((fd = open(file, O_RDONLY)) < 0) {
weprintf("open %s:", file);
(*noread)++;
continue;
}
if (cryptsum(ops, fp, file, md)) {
if (cryptsum(ops, fd, file, md)) {
(*noread)++;
continue;
}
@@ -77,7 +79,7 @@ mdchecklist(FILE *listfp, struct crypt_ops *ops, uint8_t *md, size_t sz,
} else {
(*formatsucks)++;
}
fclose(fp);
close(fd);
}
free(line);
}
@@ -124,11 +126,11 @@ cryptcheck(int argc, char *argv[], struct crypt_ops *ops, uint8_t *md, size_t sz
int
cryptmain(int argc, char *argv[], struct crypt_ops *ops, uint8_t *md, size_t sz)
{
FILE *fp;
int fd;
int ret = 0;
if (argc == 0) {
if (cryptsum(ops, stdin, "<stdin>", md))
if (cryptsum(ops, 0, "<stdin>", md))
ret = 1;
else
mdprint(md, "<stdin>", sz);
@@ -136,18 +138,18 @@ cryptmain(int argc, char *argv[], struct crypt_ops *ops, uint8_t *md, size_t sz)
for (; *argv; argc--, argv++) {
if ((*argv)[0] == '-' && !(*argv)[1]) {
*argv = "<stdin>";
fp = stdin;
} else if (!(fp = fopen(*argv, "r"))) {
weprintf("fopen %s:", *argv);
fd = 0;
} else if ((fd = open(*argv, O_RDONLY)) < 0) {
weprintf("open %s:", *argv);
ret = 1;
continue;
}
if (cryptsum(ops, fp, *argv, md))
if (cryptsum(ops, fd, *argv, md))
ret = 1;
else
mdprint(md, *argv, sz);
if (fp != stdin && fshut(fp, *argv))
ret = 1;
if (fd != 0)
close(fd);
}
}
@@ -155,16 +157,15 @@ cryptmain(int argc, char *argv[], struct crypt_ops *ops, uint8_t *md, size_t sz)
}
int
cryptsum(struct crypt_ops *ops, FILE *fp, const char *f,
uint8_t *md)
cryptsum(struct crypt_ops *ops, int fd, const char *f, uint8_t *md)
{
uint8_t buf[BUFSIZ];
size_t n;
ssize_t n;
ops->init(ops->s);
while ((n = fread(buf, 1, sizeof(buf), fp)) > 0)
while ((n = read(fd, buf, sizeof(buf))) > 0)
ops->update(ops->s, buf, n);
if (ferror(fp)) {
if (n < 0) {
weprintf("%s: read error:", f);
return 1;
}