Luna/apps/sh.c
apio f084b57f39
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kernel+sh: Allow using Ctrl+D to send EOF
2023-03-24 17:21:21 +01:00

110 lines
2.2 KiB
C

#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
static char** split_command_into_argv(const char* cmd)
{
size_t argc = 1;
char* str = strdup(cmd);
char** arr = calloc(sizeof(char*), argc);
char* segment = strtok(str, " \n");
arr[argc - 1] = segment;
if (segment == NULL) return arr;
argc++;
arr = realloc(arr, sizeof(char*) * argc);
for (;;)
{
char* segment = strtok(NULL, " \n");
arr[argc - 1] = segment;
if (segment == NULL) break;
argc++;
arr = realloc(arr, sizeof(char*) * argc);
}
return arr;
}
static char* join_path(const char* str1, const char* str2)
{
char* buf = malloc(strlen(str1) + strlen(str2) + 1);
strlcpy(buf, str1, strlen(str1) + 1);
strncat(buf, str2, strlen(str2));
return buf;
}
static int execute_in_path(const char* dir, char** argv)
{
char* path = join_path(dir, argv[0]);
int err = errno;
int status = execv(path, argv);
free(path);
if (errno == ENOENT)
{
errno = err;
return 0;
}
return status;
}
static int sh_execvp(char** argv)
{
if (strchr(argv[0], '/'))
{
// Relative paths do not need path resolution.
return execv(argv[0], argv);
}
if (execute_in_path("/bin/", argv) != 0) return -1;
if (execute_in_path("/sbin/", argv) != 0) return -1;
if (execute_in_path("/usr/bin/", argv) != 0) return -1;
if (execute_in_path("/usr/local/bin/", argv) != 0) return -1;
errno = ENOENT;
return -1;
}
int main()
{
while (1)
{
fputs("sh$ ", stdout);
char command[4096];
char* rc = fgets(command, sizeof(command), stdin);
if (!rc) return 0;
pid_t child = fork();
if (child < 0)
{
perror("fork");
return 1;
}
if (child == 0)
{
char** argv = split_command_into_argv(command);
if (argv[0] == NULL) return 0;
sh_execvp(argv);
perror(argv[0]);
return 1;
}
if (waitpid(child, NULL, 0) < 0)
{
perror("waitpid");
return 1;
}
}