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Diffstat (limited to '')
| -rw-r--r-- | src/nice.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/src/nice.c b/src/nice.c new file mode 100644 index 0000000..0933e85 --- /dev/null +++ b/src/nice.c @@ -0,0 +1,221 @@ +/* nice -- run a program with modified niceness + Copyright (C) 1990-2020 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* David MacKenzie <djm@gnu.ai.mit.edu> */ + +#include <config.h> +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> + +#include "system.h" + +#if ! HAVE_NICE +/* Include this after "system.h" so we're sure to have definitions + (from time.h or sys/time.h) required for e.g. the ru_utime member. */ +# include <sys/resource.h> +#endif + +#include "die.h" +#include "error.h" +#include "quote.h" +#include "xstrtol.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "nice" + +#define AUTHORS proper_name ("David MacKenzie") + +#if HAVE_NICE +# define GET_NICENESS() nice (0) +#else +# define GET_NICENESS() getpriority (PRIO_PROCESS, 0) +#endif + +#ifndef NZERO +# define NZERO 20 +#endif + +/* This is required for Darwin Kernel Version 7.7.0. */ +#if NZERO == 0 +# undef NZERO +# define NZERO 20 +#endif + +static struct option const longopts[] = +{ + {"adjustment", required_argument, NULL, 'n'}, + {GETOPT_HELP_OPTION_DECL}, + {GETOPT_VERSION_OPTION_DECL}, + {NULL, 0, NULL, 0} +}; + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + emit_try_help (); + else + { + printf (_("Usage: %s [OPTION] [COMMAND [ARG]...]\n"), program_name); + printf (_("\ +Run COMMAND with an adjusted niceness, which affects process scheduling.\n\ +With no COMMAND, print the current niceness. Niceness values range from\n\ +%d (most favorable to the process) to %d (least favorable to the process).\n\ +"), + - NZERO, NZERO - 1); + + emit_mandatory_arg_note (); + + fputs (_("\ + -n, --adjustment=N add integer N to the niceness (default 10)\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME); + emit_ancillary_info (PROGRAM_NAME); + } + exit (status); +} + +static bool +perm_related_errno (int err) +{ + return err == EACCES || err == EPERM; +} + +int +main (int argc, char **argv) +{ + int current_niceness; + int adjustment = 10; + char const *adjustment_given = NULL; + bool ok; + int i; + + initialize_main (&argc, &argv); + set_program_name (argv[0]); + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + initialize_exit_failure (EXIT_CANCELED); + atexit (close_stdout); + + for (i = 1; i < argc; /* empty */) + { + char const *s = argv[i]; + + if (s[0] == '-' && ISDIGIT (s[1 + (s[1] == '-' || s[1] == '+')])) + { + adjustment_given = s + 1; + ++i; + } + else + { + int c; + int fake_argc = argc - (i - 1); + char **fake_argv = argv + (i - 1); + + /* Ensure that any getopt diagnostics use the right name. */ + fake_argv[0] = argv[0]; + + /* Initialize getopt_long's internal state. */ + optind = 0; + + c = getopt_long (fake_argc, fake_argv, "+n:", longopts, NULL); + i += optind - 1; + + switch (c) + { + case 'n': + adjustment_given = optarg; + break; + + case -1: + break; + + case_GETOPT_HELP_CHAR; + + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + + default: + usage (EXIT_CANCELED); + break; + } + + if (c == -1) + break; + } + } + + if (adjustment_given) + { + /* If the requested adjustment is outside the valid range, + silently bring it to just within range; this mimics what + "setpriority" and "nice" do. */ + enum { MIN_ADJUSTMENT = 1 - 2 * NZERO, MAX_ADJUSTMENT = 2 * NZERO - 1 }; + long int tmp; + if (LONGINT_OVERFLOW < xstrtol (adjustment_given, NULL, 10, &tmp, "")) + die (EXIT_CANCELED, 0, _("invalid adjustment %s"), + quote (adjustment_given)); + adjustment = MAX (MIN_ADJUSTMENT, MIN (tmp, MAX_ADJUSTMENT)); + } + + if (i == argc) + { + if (adjustment_given) + { + error (0, 0, _("a command must be given with an adjustment")); + usage (EXIT_CANCELED); + } + /* No command given; print the niceness. */ + errno = 0; + current_niceness = GET_NICENESS (); + if (current_niceness == -1 && errno != 0) + die (EXIT_CANCELED, errno, _("cannot get niceness")); + printf ("%d\n", current_niceness); + return EXIT_SUCCESS; + } + + errno = 0; +#if HAVE_NICE + ok = (nice (adjustment) != -1 || errno == 0); +#else + current_niceness = GET_NICENESS (); + if (current_niceness == -1 && errno != 0) + die (EXIT_CANCELED, errno, _("cannot get niceness")); + ok = (setpriority (PRIO_PROCESS, 0, current_niceness + adjustment) == 0); +#endif + if (!ok) + { + error (perm_related_errno (errno) ? 0 + : EXIT_CANCELED, errno, _("cannot set niceness")); + /* error() flushes stderr, but does not check for write failure. + Normally, we would catch this via our atexit() hook of + close_stdout, but execvp() gets in the way. If stderr + encountered a write failure, there is no need to try calling + error() again. */ + if (ferror (stderr)) + return EXIT_CANCELED; + } + + execvp (argv[i], &argv[i]); + + int exit_status = errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE; + error (0, errno, "%s", quote (argv[i])); + return exit_status; +} |