This commit adds the renice command and its man page,
it also introduces some fixes:
* Makes nice command more solid, it also makes it respect POSIX return values.
* Fixes estrtol, which produced a misleading error on out of range errors.
* Fixes chgrp.1 NAME section.
---
Makefile | 1 +
chgrp.1 | 2 +-
nice.c | 74 +++++++++++++++++++++------------
renice.1 | 97 +++++++++++++++++++++++++++++++++++++++++++
renice.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
util/estrtol.c | 9 ++--
6 files changed, 278 insertions(+), 32 deletions(-)
create mode 100644 renice.1
create mode 100644 renice.c
diff --git a/Makefile b/Makefile
index d90d690..b7d0fa7 100644
--- a/Makefile
+++ b/Makefile
@@ -49,6 +49,7 @@ SRC = \
paste.c \
printenv.c \
pwd.c \
+ renice.c \
rm.c \
rmdir.c \
sleep.c \
diff --git a/chgrp.1 b/chgrp.1
index 7196080..07a33a6 100644
--- a/chgrp.1
+++ b/chgrp.1
@@ -1,6 +1,6 @@
.TH CHGRP 1 sbase\-VERSION
.SH NAME
-nice \- invoke a utility with an altered nice value
+chgrp \- change the file group ownership
.SH SYNOPSIS
.B chgrp
.RB [ \-R ]
diff --git a/nice.c b/nice.c
index dcbb05f..773f11b 100644
--- a/nice.c
+++ b/nice.c
@@ -1,38 +1,58 @@
/* See LICENSE file for copyright and license details. */
+#include <errno.h>
+#include <limits.h>
#include <unistd.h>
#include <stdio.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <string.h>
#include "util.h"
-static void
-usage(void)
-{
- eprintf("usage: nice [-n inc] command [options ...]\n");
-}
+#ifndef NZERO
+/* limits.h could omit NZERO, but sane systems have it */
+#define NZERO 20
+#endif
+
+static void eusage(void);
int
main(int argc, char **argv)
{
- int inc = 10;
-
- ARGBEGIN {
- case 'n':
- inc = atoi(EARGF(usage()));
- break;
- default:
- usage();
- } ARGEND;
-
- nice(inc); /* POSIX specifies the nice failure still invokes the
command. */
-
- if(!*argv)
- usage();
-
- execvp(*argv, argv);
- eprintf("nice: '%s': %s\n", *argv, strerror(errno));
-
- return EXIT_FAILURE;
+ const char *adj = "10";
+ long val;
+ int c;
+
+ while((c = getopt(argc, argv, "n:")) != -1)
+ switch(c) {
+ case 'n':
+ adj = optarg;
+ break;
+ case '?':
+ default:
+ eusage();
+ break;
+ }
+
+ argc -= optind;
+ argv += optind;
+ if(argc == 0)
+ eusage();
+
+ /* clamp the value to a meaningful range */
+ val = estrtol(adj, 10);
+ val = MAX(1 - NZERO * 2, MIN(val, NZERO * 2 - 1));
+
+ errno = 0;
+ nice((int)val);
+ if(errno != 0)
+ perror("can't adjust niceness");
+
+ /* POSIX specifies the nice failure still invokes the command */
+ execvp(argv[0], argv);
+ /* reached only on failure */
+ perror(argv[0]);
+ return (errno == ENOENT)? 127 : 126;
}
+static void
+eusage(void)
+{
+ eprintf("usage: nice [-n inc] command [options ...]\n");
+}
diff --git a/renice.1 b/renice.1
new file mode 100644
index 0000000..1a46e4c
--- /dev/null
+++ b/renice.1
@@ -0,0 +1,97 @@
+.TH PASTE 1 renice-VERSION "Jun 2013"
+.SH NAME
+renice \- set nice values of running processes
+.SH "SYNOPSIS"
+.PP
+.B renice
+.B \-n
+.I increment
+[
+.B \-g
+|
+.B \-p
+|
+.B \-u
+]
+.I ID...
+.SH DESCRIPTION
+The
+.B renice
+utility requests that the nice values of one or more
+running processes be changed. By default, the applicable processes
+are specified by their process IDs. When a process group is specified
+(see
+.B -g
+), the request applies to all processes in the process group. If the
+requested increment would raise or lower the nice value of the
+executed utility beyond its limits, then the limit whose value was
+exceeded is used. When a user is reniced, the request applies to all
+processes whose saved set-user-ID matches the user ID corresponding to
+the user. Regardless of which options are supplied or any other factor,
+renice does not alter the nice values of any process unless the user
+requesting such a change has appropriate privileges to do so for the
+specified process. If the user lacks appropriate privileges to perform
+the requested action, the utility returns an error status.
+The saved set-user-ID of the user's process is checked instead of its
+effective user ID when renice attempts to determine the user ID of the
+process in order to determine whether the user has appropriate privileges.
+.SH OPTIONS
+.TP
+.B \-g
+interpret all operands as unsigned decimal integer process group IDs.
+.TP
+.B \-n
+.I increment
+specify how the nice value of the specified process or processes
+is to be adjusted. The increment option-argument is a positive or
+negative decimal integer used to modify the nice value of the
+specified process or processes. positive increment values cause a
+lower nice value. Negative increment values may require appropriate
+privileges and cause a higher nice value.
+.TP
+.B \-p
+interpret all operands as unsigned decimal integer process IDs.
+The
+.B \-p
+option is the default if no options are specified.
+.TP
+.B \-u
+interpret all operands as users. If a user exists with a user name
+equal to the operand, then the user ID of that user is used in further
+processing. Otherwise, if the operand represents an unsigned decimal
+integer, used as the numeric user ID of the user.
+.SH EXIT VALUES
+On successful completion 0 is returned, a value which is >0 is
+returned on error.
+.SH FILES
+.TP
+.I /etc/passwd
+used to map user names to user ID's.
+.SH CONFORMING TO
+The
+.B renice
+utility is IEEE Std 1003.1-2001 (POSIX.1) compatible.
+.SH EXAMPLES
+.TP
+.I "renice -n 5 -p 987 32"
+.PP
+Adjust the nice value so that process IDs 987 and 32 would have a
+lower nice value.
+.TP
+.I "renice -n -4 -g 324 76"
+.PP
+Adjust the nice value so that group IDs 324 and 76 would have a
+higher nice value, if the user has the appropriate privileges to do so.
+.TP
+.I "renice -n 4 -u 8 sas"
+.PP
+Adjust the nice value so that numeric user ID 8 and user sas would
+have a lower nice value.
+Useful nice value increments on historical systems include
+19 or 20 (the affected processes run only when nothing else in the
+system attempts to run) and any negative number
+(to make processes run faster).
+.SH AUTHOR
+Written by Lorenzo Cogotti.
+.SH SEE ALSO
+.BR nice(1)
diff --git a/renice.c b/renice.c
new file mode 100644
index 0000000..aed8fbc
--- /dev/null
+++ b/renice.c
@@ -0,0 +1,127 @@
+/* See LICENSE file for copyright and license details. */
+#include <errno.h>
+#include <limits.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <unistd.h>
+#include "util.h"
+
+#ifndef NZERO
+/* limits.h could omit NZERO, but sane systems have it */
+#define NZERO 20
+#endif
+
+static int strtop(const char *);
+static bool renice(int, int, int);
+static void eusage(void);
+
+int
+main(int argc, char **argv)
+{
+ const char *adj = "10";
+ long val;
+ int i, c, which = PRIO_PROCESS, status = 0;
+
+ while((c = getopt(argc, argv, "n:gpu")) != -1)
+ switch(c) {
+ case 'n':
+ adj = optarg;
+ break;
+ case 'g':
+ which = PRIO_PGRP;
+ break;
+ case 'p':
+ which = PRIO_PROCESS;
+ break;
+ case 'u':
+ which = PRIO_USER;
+ break;
+ case '?':
+ default:
+ eusage();
+ break;
+ }
+
+ argc -= optind;
+ argv += optind;
+ if(argc == 0)
+ eusage();
+
+ /* clamp value to a meaningful range */
+ val = estrtol(adj, 10);
+ val = MAX(1 - NZERO * 2, MIN(val, NZERO * 2 - 1));
+ for(i = 0; i < argc; i++) {
+ int who = -1;
+
+ if(which == PRIO_USER) {
+ const struct passwd *pwd;
+
+ errno = 0;
+ do pwd = getpwnam(argv[i]); while(errno == EINTR);
+
+ if(pwd)
+ who = pwd->pw_uid;
+ else if(errno != 0) {
+ perror("can't read passwd");
+ status = 1;
+ continue;
+ }
+ }
+ if(who < 0)
+ who = strtop(argv[i]);
+
+ if(who < 0 || !renice(which, who, (int)val))
+ status = 1;
+ }
+
+ return status;
+}
+
+static int
+strtop(const char *s)
+{
+ char *end;
+ long n;
+
+ errno = 0;
+ n = strtol(s, &end, 10);
+ if(*end != '\0') {
+ fprintf(stderr, "%s: not an integer\n", s);
+ return -1;
+ }
+ if(errno != 0 || n <= 0 || n > INT_MAX) {
+ fprintf(stderr, "%s: invalid value\n", s);
+ return -1;
+ }
+
+ return (int)n;
+}
+
+static bool
+renice(int which, int who, int adj)
+{
+ errno = 0;
+ adj += getpriority(which, who);
+ if (errno != 0) {
+ fprintf(stderr, "can't get %d nice level: %s\n", who,
strerror(errno));
+ return false;
+ }
+
+ adj = MAX(PRIO_MIN, MIN(adj, PRIO_MAX));
+ if(setpriority(which, who, adj) == -1) {
+ fprintf(stderr, "can't set %d nice level: %s\n", who,
strerror(errno));
+ return false;
+ }
+
+ return true;
+}
+
+static void
+eusage(void)
+{
+ eprintf("renice -n increment [-g | -p | -u] ID ...\n");
+}
diff --git a/util/estrtol.c b/util/estrtol.c
index d481445..ac37b8c 100644
--- a/util/estrtol.c
+++ b/util/estrtol.c
@@ -13,13 +13,14 @@ estrtol(const char *s, int base)
errno = 0;
n = strtol(s, &end, base);
- if(*end != '\0' || errno != 0) {
- if(base == 0) {
+ if(*end != '\0') {
+ if(base == 0)
eprintf("%s: not an integer\n", s);
- } else {
+ else
eprintf("%s: not a base %d integer\n", s, base);
- }
}
+ if(errno != 0)
+ eprintf("%s:", s);
return n;
}
--
1.8.2
