ref: 6d5e003446292f20c769c2a32674f9f2f4b41389 mrsh/shell/job.c -rw-r--r-- 4.2 KiB View raw
                                                                                
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
#define _POSIX_C_SOURCE 1
#include <assert.h>
#include <errno.h>
#include <mrsh/array.h>
#include <mrsh/shell.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "shell/job.h"
#include "shell/process.h"

static const int ignored_signals[] = {
	SIGINT,
	SIGQUIT,
	SIGTSTP,
	SIGTTIN,
	SIGTTOU,
};

static const size_t IGNORED_SIGNALS_LEN =
	sizeof(ignored_signals) / sizeof(ignored_signals[0]);

bool mrsh_set_job_control(struct mrsh_state *state, bool enabled) {
	assert(state->fd >= 0);

	if (state->job_control == enabled) {
		return true;
	}

	if (enabled) {
		// Loop until we are in the foreground
		while (true) {
			pid_t pgid = getpgrp();
			if (tcgetpgrp(state->fd) == pgid) {
				break;
			}
			kill(-pgid, SIGTTIN);
		}

		// Ignore interactive and job-control signals
		struct sigaction sa = { .sa_handler = SIG_IGN };
		sigemptyset(&sa.sa_mask);
		for (size_t i = 0; i < IGNORED_SIGNALS_LEN; ++i) {
			if (sigaction(ignored_signals[i], &sa, NULL) != 0) {
				fprintf(stderr, "sigaction failed: %s\n", strerror(errno));
				return false;
			}
		}

		// Put ourselves in our own process group
		state->pgid = getpid();
		if (setpgid(state->pgid, state->pgid) != 0) {
			fprintf(stderr, "setpgid failed: %s\n", strerror(errno));
			return false;
		}

		// Grab control of the terminal
		if (tcsetpgrp(state->fd, state->pgid) != 0) {
			fprintf(stderr, "tcsetpgrp failed: %s\n", strerror(errno));
			return false;
		}
		// Save default terminal attributes for the shell
		if (tcgetattr(state->fd, &state->term_modes) != 0) {
			fprintf(stderr, "tcgetattr failed: %s\n", strerror(errno));
			return false;
		}
	} else {
		return false; // TODO
	}

	state->job_control = enabled;
	return true;
}

static void array_remove(struct mrsh_array *array, size_t i) {
	memmove(&array->data[i], &array->data[i + 1],
		(array->len - i - 1) * sizeof(void *));
	--array->len;
}

struct mrsh_job *job_create(struct mrsh_state *state, pid_t pgid) {
	struct mrsh_job *job = calloc(1, sizeof(struct mrsh_job));
	job->state = state;
	job->pgid = pgid;
	mrsh_array_add(&state->jobs, job);
	return job;
}

void job_destroy(struct mrsh_job *job) {
	if (job == NULL) {
		return;
	}

	if (job->state->foreground_job == job) {
		job_set_foreground(job, false);
	}

	struct mrsh_state *state = job->state;
	for (size_t i = 0; i < state->jobs.len; ++i) {
		if (state->jobs.data[i] == job) {
			array_remove(&state->jobs, i);
			break;
		}
	}

	for (size_t j = 0; j < job->processes.len; ++j) {
		process_destroy(job->processes.data[j]);
	}
	mrsh_array_finish(&job->processes);
	free(job);
}

void job_add_process(struct mrsh_job *job, struct process *proc) {
	mrsh_array_add(&job->processes, proc);
}

bool job_terminated(struct mrsh_job *job) {
	for (size_t j = 0; j < job->processes.len; ++j) {
		struct process *proc = job->processes.data[j];
		if (!proc->terminated) {
			return false;
		}
	}
	return true;
}

bool job_stopped(struct mrsh_job *job) {
	for (size_t j = 0; j < job->processes.len; ++j) {
		struct process *proc = job->processes.data[j];
		if (!proc->terminated && !proc->stopped) {
			return false;
		}
	}
	return true;
}

void job_set_foreground(struct mrsh_job *job, bool foreground) {
	struct mrsh_state *state = job->state;

	if (foreground && state->foreground_job != job) {
		assert(state->foreground_job == NULL);
		tcsetpgrp(state->fd, job->pgid);
		state->foreground_job = job;
	}

	if (!foreground && state->foreground_job == job) {
		// Put the shell back in the foreground
		tcsetpgrp(state->fd, state->pgid);
		// Restore the shell’s terminal modes
		tcgetattr(state->fd, &job->term_modes);
		tcsetattr(state->fd, TCSADRAIN, &state->term_modes);
		state->foreground_job = NULL;
	}
}

bool init_job_child_process(struct mrsh_state *state) {
	if (!state->job_control) {
		return true;
	}

	struct sigaction sa = { .sa_handler = SIG_DFL };
	sigemptyset(&sa.sa_mask);
	for (size_t i = 0; i < IGNORED_SIGNALS_LEN; ++i) {
		if (sigaction(ignored_signals[i], &sa, NULL) != 0) {
			fprintf(stderr, "sigaction failed: %s\n", strerror(errno));
			return false;
		}
	}

	return true;
}

void update_job(struct mrsh_state *state, pid_t pid, int stat) {
	update_process(state, pid, stat);
}