Add ps(1).

doc/user-guide

@@ -202,6 +202,7 @@ Sortix comes with a number of home-made programs. Here is an overview:
 * `mktemp` - create temporary file or directory
 * `mv` - move a file
 * `pager` - display file page by page
+* `ps` - report a snapshot of the current processes
 * `pwd` - print current directory path
 * `realpath` - canonicalize filesystem paths
 * `regress` - run system tests

utils/.gitignore

@@ -29,6 +29,7 @@ mkdir
 mktemp
 mv
 pager
+ps
 pwd
 realpath
 rm

utils/Makefile

@@ -41,6 +41,7 @@ mkdir \
 mktemp \
 mv \
 pager \
+ps \
 pwd \
 realpath \
 rm \

utils/ps.cpp

@@ -0,0 +1,198 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2015.
+
+    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 <http://www.gnu.org/licenses/>.
+
+    ps.cpp
+    Lists processes.
+
+*******************************************************************************/
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <errno.h>
+#include <locale.h>
+#include <psctl.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static char* get_program_path_of_pid(pid_t pid)
+{
+	struct psctl_program_path ctl;
+	memset(&ctl, 0, sizeof(ctl));
+	ctl.buffer = NULL;
+	ctl.size = 0;
+	if ( psctl(pid, PSCTL_PROGRAM_PATH, &ctl) < 0 )
+		return NULL;
+	while ( true )
+	{
+		char* new_buffer = (char*) realloc(ctl.buffer, ctl.size);
+		if ( !new_buffer )
+			return free(ctl.buffer), (char*) NULL;
+		ctl.buffer = new_buffer;
+		if ( psctl(pid, PSCTL_PROGRAM_PATH, &ctl) == 0 )
+			return ctl.buffer;
+		if ( errno != ERANGE )
+			return free(ctl.buffer), (char*) NULL;
+	}
+}
+
+static void compact_arguments(int* argc, char*** argv)
+{
+	for ( int i = 0; i < *argc; i++ )
+	{
+		while ( i < *argc && !(*argv)[i] )
+		{
+			for ( int n = i; n < *argc; n++ )
+				(*argv)[n] = (*argv)[n+1];
+			(*argc)--;
+		}
+	}
+}
+
+static void help(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "Usage: %s [OPTION]...\n", argv0);
+	fprintf(fp, "List processes.\n");
+}
+
+static void version(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
+	fprintf(fp, "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n");
+	fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
+	fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
+}
+
+int main(int argc, char* argv[])
+{
+	setlocale(LC_ALL, "");
+
+	bool select_all = false;
+	bool show_full = false;
+	bool show_long = false;
+
+	const char* argv0 = argv[0];
+	for ( int i = 1; i < argc; i++ )
+	{
+		const char* arg = argv[i];
+		if ( arg[0] != '-' || !arg[1] )
+			continue;
+		argv[i] = NULL;
+		if ( !strcmp(arg, "--") )
+			break;
+		if ( arg[1] != '-' )
+		{
+			while ( char c = *++arg ) switch ( c )
+			{
+			case 'a': select_all = true; break;
+			case 'A': select_all = true; break;
+			case 'd': select_all = true; break;
+			case 'e': select_all = true; break;
+			case 'f': show_full = true; break;
+			//case 'g': break;
+			//case 'G': break;
+			case 'l': show_long = true; break;
+			//case 'n': break;
+			//case 'o': break;
+			//case 'p': break;
+			//case 't': break;
+			//case 'u': break;
+			//case 'U': break;
+			default:
+				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
+				help(stderr, argv0);
+				exit(1);
+			}
+		}
+		else if ( !strcmp(arg, "--help") )
+			help(stdout, argv0), exit(0);
+		else if ( !strcmp(arg, "--version") )
+			version(stdout, argv0), exit(0);
+		else
+		{
+			fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
+			help(stderr, argv0);
+			exit(1);
+		}
+	}
+
+	compact_arguments(&argc, &argv);
+
+	if ( 1 < argc )
+		err(1, "extra operand: %s", argv[1]);
+
+	if ( show_full || show_long )
+		printf("UID\t");
+	printf("PID\t");
+	if ( show_full || show_long )
+		printf("PPID\t");
+	if ( show_long )
+		printf("NI  ");
+	printf("TTY  ");
+	printf("TIME\t   ");
+	printf("CMD\n");
+	pid_t pid = 0;
+	while ( true )
+	{
+		struct psctl_next_pid ctl_next_pid;
+		if ( psctl(pid, PSCTL_NEXT_PID, &ctl_next_pid) < 0 )
+			err(1, "psctl: PSCTL_NEXT_PID");
+		if ( (pid = ctl_next_pid.next_pid) == -1 )
+			break;
+		struct psctl_stat psst;
+		if ( psctl(pid, PSCTL_STAT, &psst) < 0 )
+		{
+			if ( errno != ESRCH )
+				warn("psctl: PSCTL_STAT: [%" PRIiPID "]", pid);
+			continue;
+		}
+		if ( !select_all && psst.euid != geteuid() )
+			continue;
+		if ( show_full )
+		{
+			struct passwd* pwd = getpwuid(psst.uid);
+			if ( pwd )
+				printf("%s\t", pwd->pw_name);
+			else
+				printf("%" PRIuUID "\t", psst.uid);
+		}
+		else if ( show_long )
+			printf("%" PRIuUID "\t", psst.uid);
+		printf("%" PRIiPID "\t", pid);
+		if ( show_full || show_long )
+			printf("%" PRIiPID "\t", psst.ppid);
+		if ( show_long )
+			printf("%-4i", psst.nice);
+		printf("tty  ");
+		time_t time = psst.tmns.tmns_utime.tv_sec;
+		int hours = (time / (60 * 60)) % 24;
+		int minutes = (time / 60) % 60;
+		int seconds = (time / 1) % 60;
+		printf("%02i:%02i:%02i  ", hours, minutes, seconds);
+		char* program_path = get_program_path_of_pid(pid);
+		// TODO: Strip special characters from the process name lest an attacker
+		//       do things to the user's terminal.
+		printf("%s", program_path ? program_path : "<unknown>");
+		free(program_path);
+		printf("\n");
+	}
+
+	return ferror(stdout) || fflush(stdout) == EOF ? 1 : 0;
+}