Added feature 'all' (-a/--all) to show all processes running on the machine.

Instead of re-writing a new function, a simple flag was added (x->flag).

1 files changed, 207 insertions, 0 deletions

diff --git a/src/chproc.c b/src/chproc.c
new file mode 100644
index 0000000..46876a5
--- /dev/null
+++ b/src/chproc.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * chproc.c - simple process checker
+ *
+ * Iterate over /proc and print PIDs of processes matching the given name.
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <ctype.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <limits.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <getopt.h>
+#include <signal.h>
+#include <stdbool.h>
+
+#define PROGRAM_NAME "chproc"
+
+struct options {
+	int list;
+	int all;
+	int kill;
+	char *process_name;
+	char *process_pid;
+};
+
+
+static void options_init(struct options *x)
+{
+	x->list = false;
+	x->all	= false;
+	x->kill = false;
+	x->process_pid = NULL;
+	x->process_name = NULL;
+}
+
+
+static void usage(void)
+{
+	fprintf(stderr,
+		"Usage: %s <option> [process_name, pid]\n"
+		" -l, --list <name>	list all pid for that process\n"
+		" -a, --all		list all processes\n"
+		" -k, --kill <PID>	kill a proces give then PID\n"
+		, PROGRAM_NAME);
+}
+
+
+
+static int process_list(DIR *dir,
+		const char *proc_name,
+		struct options *x)
+{
+	char path[PATH_MAX];
+	char buffer[256];
+	char *endptr;
+	FILE *f;
+	int count;
+	long pid;
+	struct dirent *entry;
+	size_t len;
+
+	count = 0;
+
+	while ((entry = readdir(dir)) != NULL) {
+		/* skip "." and ".." */
+		if (strcmp(entry->d_name, ".") == 0)
+			continue;
+		if (strcmp(entry->d_name, "..") == 0)
+			continue;
+
+
+		pid = strtol(entry->d_name, &endptr, 10);
+
+		if (*endptr != '\0') /* not a pure number */
+			continue;
+
+		snprintf(path, sizeof(path), "/proc/%ld/comm", pid);
+
+		f = fopen(path, "r");
+
+		if (!f) {
+			fprintf(stderr, "Failed to open %s: %s\n",
+				path, strerror(errno));
+			continue;
+		}
+
+		if (!(fgets(buffer, sizeof(buffer), f)))
+			continue;
+
+		len = strlen(buffer);
+
+		if (len > 0 && buffer[len-1] == '\n')
+			buffer[len-1] = '\0';
+
+		/* flag instead of re-writing a function */
+		if (x->list) {
+			if (strcmp(buffer, proc_name) == 0) {
+				printf("%s - %s\n", entry->d_name, buffer);
+				++count;
+			}
+		} else {
+			printf("%s - %s\n", entry->d_name, buffer);
+			++count;
+		}
+		fclose(f);
+	}
+
+	closedir(dir);
+
+	if (count == 0)
+		return 1;
+	else
+		return 0;
+}
+
+
+static int process_kill(const char *process_id)
+{
+	pid_t pid;
+
+	if (atoi(process_id) < 1) {
+		fprintf(stderr, "'%s': not a pid or valid job\n", process_id);
+		usage();
+		return 1;
+	}
+
+	pid = (pid_t) atoi(process_id);
+
+	if (kill(pid, SIGTERM) == -1) {
+		perror("kill failed");
+		return 1;
+	}
+
+	printf("Process '%d' killed.\n", pid);
+	return 0;
+}
+
+
+int main(int argc, char *argv[])
+{
+	int opt;
+	DIR *dir_proc;
+
+	struct options x;
+
+	struct option long_options[] = {
+		{"list", required_argument, 0, 'l'},
+		{"all", no_argument, 0, 'a'},
+		{"kill", required_argument, 0, 'k'},
+		{0, 0, 0, 0}
+	};
+
+	options_init(&x);
+
+	/* /proc/ must to exist */
+	dir_proc = opendir("/proc");
+	if (dir_proc == NULL) {
+		fprintf(stderr, "/proc/ not found.\n");
+		return EXIT_FAILURE;
+	}
+
+	if (argc < 2) {
+		usage();
+		return 2;
+	}
+
+	while ((opt = getopt_long(argc, argv, "l:k:a",
+		long_options, NULL)) != -1) {
+		switch (opt) {
+		case 'l':
+			x.list = true;
+			x.process_name = optarg;
+			break;
+		case 'a':
+			x.all = true;
+			break;
+		case 'k':
+			x.kill = true;
+			x.process_pid = optarg;
+			break;
+		default:
+			fprintf(stderr,
+				"Unknow option.\n");
+			usage();
+			exit(2);
+		}
+	}
+
+	if (x.list || x.all)
+		if (process_list(dir_proc, x.process_name, &x) == 1)
+			return 1;
+
+	if (x.kill)
+		if (process_kill(x.process_pid) == 1)
+			return 1;
+
+	return 0;
+}
+
+
+