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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
|
/* noshmore
* an extended version of nosh,
* the minimal POSIX C shell.
* -> generally: adds some functionality.
*
* von czjstmax, <jstmaxlol at disroot dot org>
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <stdbool.h>
#include <wordexp.h>
#include <sys/wait.h>
#include <readline/readline.h>
#include <readline/history.h>
#define MAX_ALIASES 256
typedef struct {
char *dst;
char *src;
} Alias;
Alias aliases[MAX_ALIASES];
int alias_count = 0;
void handlecc(int sig);
Alias CreateAlias(char *dst, char *src);
void FreeAll();
void FreeAliases();
char *line = NULL;
wordexp_t p;
int main(void)
{
signal(SIGINT, handlecc);
char *USER = getenv("USER");
if (!USER)
USER = "anon";
char *HOME = getenv("HOME");
if (!HOME)
HOME = ".";
while (true) {
char prompt[strlen(USER) + strlen("$ ") + 1];
snprintf(prompt, sizeof(prompt), "%s$ ", USER);
line = readline(prompt);
if (!line)
break;
if (*line)
add_history(line);
if (wordexp(line, &p, 0) != 0) {
fprintf(stderr, "nsh+! ERROR while parsing\n");
free(line);
continue;
}
// built-ins
if (p.we_wordc == 0) {
FreeAll();
continue;
}
if (strcmp(p.we_wordv[0], ":q") == 0 || strcmp(p.we_wordv[0], "exit") == 0) {
FreeAll();
FreeAliases();
return 0;
}
else if (strcmp(p.we_wordv[0], "echo") == 0) {
for (size_t i = 1; i < p.we_wordc; i++)
printf("%s ", p.we_wordv[i]);
if (p.we_wordc >= 2) {
if (strcmp(p.we_wordv[1], "-c") != 0)
printf("\n");
else continue;
}
}
else if (strcmp(p.we_wordv[0], "alias") == 0) {
if (p.we_wordc <= 2) {
fprintf(stderr, "nsh+! ERROR: expected 2 args\n");
} else {
// overwrite if exists
bool found = false;
for (int i = 0; i < alias_count; i++) {
if (strcmp(aliases[i].dst, p.we_wordv[1]) == 0) {
free(aliases[i].src);
aliases[i].src = strdup(p.we_wordv[2]);
found = true;
break;
}
}
if (!found && alias_count < MAX_ALIASES) {
aliases[alias_count++] = CreateAlias(p.we_wordv[1], p.we_wordv[2]);
}
}
}
else if (strcmp(p.we_wordv[0], "cd") == 0) {
if (p.we_wordc <= 1) {
if (chdir(HOME))
perror("nsh+! ERROR: cannot retrieve HOME, failed to change directory");
FreeAll();
continue;
}
if (chdir(p.we_wordv[1]))
perror("nsh+! ERROR: failed to change directory");
}
else if (strcmp(p.we_wordv[0], "clear") == 0) {
printf("\033[2J\033[H\033[3J");
fflush(stdout);
}
else if (strcmp(p.we_wordv[0], "help") == 0) {
printf(
"noshmore\tALIASES(%d)\n"
"an extended version of nosh, the minimal POSIX C shell.\n"
"\n"
"built-ins:\n"
"echo -> outputs a string of text, doesn't need \" enclosure.\n"
" supports '-c' for output without '\\n'"
"clear -> clears screen (and scrollback)\n"
"alias -> creates non-persistent command aliases\n"
" (i.e. alias v vim)\n"
"cd -> change working directory\n"
"help -> prints this screen\n"
"\ngithub repo: github.com/jstmaxlol/noshmore\n"
, MAX_ALIASES
);
}
else {
for (int i = 0; i < alias_count; i++) {
if (strcmp(p.we_wordv[0], aliases[i].dst) == 0) {
char new_line[81920] = {0};
strcat(new_line, aliases[i].src);
for (size_t j = 1; j < p.we_wordc; j++) {
strcat(new_line, " ");
strcat(new_line, p.we_wordv[j]);
}
wordfree(&p);
if (wordexp(new_line, &p, 0) != 0) {
fprintf(stderr, "nsh+! ERROR: alias expansion failed\n");
break;
}
break;
}
}
pid_t pid = fork();
char **argv = p.we_wordv; // pray with me now
if (pid == 0) {
execvp(p.we_wordv[0], argv);
perror("nsh+! ERROR: failed to execvp()");
FreeAll();
_exit(1);
}
else if (pid > 0) {
int status;
waitpid(pid, &status, 0);
}
else {
fprintf(stderr, "nsh+! ERROR: %s not found\n", p.we_wordv[0]);
}
}
}
}
void handlecc(int sig)
{
(void)sig;
rl_replace_line("", 0);
printf("\n");
rl_on_new_line();
rl_redisplay();
}
Alias CreateAlias(char *dst, char *src)
{
Alias alias;
alias.dst = strdup(dst);
alias.src = strdup(src);
return alias;
}
void FreeAll()
{
wordfree(&p);
free(line);
line = NULL;
}
void FreeAliases()
{
for (int i = 0; i < alias_count; i++) {
free(aliases[i].dst);
free(aliases[i].src);
}
}
|
