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Simplify argument parser by using sscanf(); simplify usage() by not

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refusing to use stdio.
Reduce nesting level in the sleep loop by returning earlier for negative
timeouts.
Limit the maximum timeout to INT_MAX seconds.

Submitted by:	bde
MFC after:	3 weeks
This commit is contained in:
Konstantin Belousov 2010-08-02 10:57:56 +00:00
parent a80f05bb73
commit f6e6dc63ab
1 changed files with 19 additions and 72 deletions
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91
bin/sleep/sleep.c
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@ -49,7 +49,6 @@ __FBSDID("$FreeBSD$");
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
static void usage(void);
@ -65,91 +64,39 @@ int
main(int argc, char *argv[])
{
struct timespec time_to_sleep;
long l, original;
int neg;
char *p;
double d;
time_t original;
char buf[2];
if (argc != 2)
usage();
p = argv[1];
/* Skip over leading whitespaces. */
while (isspace((unsigned char)*p))
++p;
/* Check for optional `+' or `-' sign. */
neg = 0;
if (*p == '-') {
neg = 1;
++p;
if (!isdigit((unsigned char)*p) && *p != '.')
usage();
}
else if (*p == '+')
++p;
/* Calculate seconds. */
if (isdigit((unsigned char)*p)) {
l = strtol(p, &p, 10);
/*
* Avoid overflow when `seconds' is huge. This assumes
* that the maximum value for a time_t is <= INT_MAX.
*/
if (l > INT_MAX)
l = INT_MAX;
} else
l = 0;
time_to_sleep.tv_sec = (time_t)l;
/* Calculate nanoseconds. */
time_to_sleep.tv_nsec = 0;
if (*p == '.') { /* Decimal point. */
l = 100000000L;
do {
if (isdigit((unsigned char)*++p))
time_to_sleep.tv_nsec += (*p - '0') * l;
else
break;
l /= 10;
} while (l);
}
/* Skip over the trailing whitespace. */
while (isspace((unsigned char)*p))
++p;
if (*p != '\0')
if (sscanf(argv[1], "%lf%1s", &d, buf) != 1)
usage();
if (d > INT_MAX)
usage();
if (d <= 0)
return (0);
original = time_to_sleep.tv_sec = (time_t)d;
time_to_sleep.tv_nsec = 1e9 * (d - time_to_sleep.tv_sec);
signal(SIGINFO, report_request);
if (!neg && (time_to_sleep.tv_sec > 0 || time_to_sleep.tv_nsec > 0)) {
original = time_to_sleep.tv_sec;
while (nanosleep(&time_to_sleep, &time_to_sleep) != 0) {
if (report_requested) {
/*
* Reporting does not bother with
* fractions of a second...
*/
warnx("about %jd second(s) left"
" out of the original %jd",
(intmax_t)time_to_sleep.tv_sec,
(intmax_t)original);
report_requested = 0;
} else
break;
}
while (nanosleep(&time_to_sleep, &time_to_sleep) != 0) {
if (report_requested) {
/* Reporting does not bother with nanoseconds. */
warnx("about %d second(s) left out of the original %d",
(int)time_to_sleep.tv_sec, (int)original);
report_requested = 0;
} else
break;
}
return (0);
}
static void
usage(void)
{
static const char msg[] = "usage: sleep seconds\n";
write(STDERR_FILENO, msg, sizeof(msg) - 1);
fprintf(stderr, "usage: sleep seconds\n");
exit(1);
}