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Mediocre conditionals in shell

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This commit is contained in:
K. Lange 2018-08-07 14:27:49 +09:00
parent 91a88aef37
commit 517335df44
1 changed files with 125 additions and 0 deletions
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125
apps/sh.c
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@ -160,6 +160,7 @@ void draw_prompt(int ret) {
fflush(stdout);
}
volatile int break_while = 0;
uint32_t child = 0;
void sig_pass(int sig) {
@ -167,6 +168,7 @@ void sig_pass(int sig) {
if (child) {
kill(child, sig);
}
break_while = sig;
}
void redraw_prompt_func(rline_context_t * context) {
@ -1123,10 +1125,133 @@ uint32_t shell_cmd_help(int argc, char * argv[]) {
return 0;
}
uint32_t shell_cmd_if(int argc, char * argv[]) {
char ** if_args = &argv[1];
char ** then_args = NULL;
char ** else_args = NULL;
for (int i = 2; i < argc; ++i) {
if (!strcmp(argv[i],"then")) {
argv[i] = NULL;
then_args = &argv[i+1];
} else if (!strcmp(argv[i],"else")) {
argv[i] = NULL;
else_args = &argv[i+1];
}
}
if (!then_args) {
fprintf(stderr, "%s: syntax error: expected 'then' clause\n", argv[0]);
return 1;
}
if (else_args && else_args < then_args) {
fprintf(stderr, "%s: syntax error: 'else' clause before 'then' clase\n", argv[0]);
return 1;
}
pid_t child_pid = fork();
if (!child_pid) {
run_cmd(if_args);
}
tcsetpgrp(STDIN_FILENO, child_pid);
child = child_pid;
int pid, ret_code = 0;
do {
pid = waitpid(-1, &ret_code, 0);
} while (pid != -1 || (pid == -1 && errno != ECHILD));
child = 0;
if (ret_code == 0) {
child_pid = fork();
if (!child_pid) {
run_cmd(then_args);
}
tcsetpgrp(STDIN_FILENO, child_pid);
child = child_pid;
do {
pid = waitpid(-1, &ret_code, 0);
} while (pid != -1 || (pid == -1 && errno != ECHILD));
child = 0;
tcsetpgrp(STDIN_FILENO, getpid());
return ret_code;
} else if (else_args) {
child_pid = fork();
if (!child_pid) {
run_cmd(else_args);
}
tcsetpgrp(STDIN_FILENO, child_pid);
child = child_pid;
do {
pid = waitpid(-1, &ret_code, 0);
} while (pid != -1 || (pid == -1 && errno != ECHILD));
child = 0;
return ret_code;
}
tcsetpgrp(STDIN_FILENO, getpid());
return 1;
}
uint32_t shell_cmd_while(int argc, char * argv[]) {
char ** while_args = &argv[1];
char ** do_args = NULL;
for (int i = 2; i < argc; ++i) {
if (!strcmp(argv[i],"do")) {
argv[i] = NULL;
do_args = &argv[i+1];
}
}
if (!do_args) {
fprintf(stderr, "%s: syntax error: expected 'do' clause\n", argv[0]);
return 1;
}
break_while = 0;
tcsetpgrp(STDIN_FILENO, getpid());
do {
pid_t child_pid = fork();
if (!child_pid) {
run_cmd(while_args);
}
child = child_pid;
int pid, ret_code = 0;
do {
pid = waitpid(-1, &ret_code, 0);
} while (pid != -1 || (pid == -1 && errno != ECHILD));
child = 0;
if (ret_code == 0) {
child_pid = fork();
if (!child_pid) {
run_cmd(do_args);
}
child = child_pid;
do {
pid = waitpid(-1, &ret_code, 0);
} while (pid != -1 || (pid == -1 && errno != ECHILD));
child = 0;
} else {
return ret_code;
}
} while (!break_while);
return 127;
}
void install_commands() {
shell_install_command("cd", shell_cmd_cd, "change directory");
shell_install_command("exit", shell_cmd_exit, "exit the shell");
shell_install_command("export", shell_cmd_export, "set environment variables");
shell_install_command("help", shell_cmd_help, "display this help text");
shell_install_command("history", shell_cmd_history, "list command history");
shell_install_command("if", shell_cmd_if, "if ... then ... [else ...]");
shell_install_command("while", shell_cmd_while, "while ... do ...");
}