struct stat st;
struct dirent dirent;
+void
+pname(char *n)
+{
+ int i;
+
+ for (i = 0; (i < DIRSIZ) && (n[i] != '\0') ; i++) {
+ printf(1, "%c", n[i]);
+ }
+ for (; i < DIRSIZ; i++)
+ printf(1, " ");
+}
+
int
main(int argc, char *argv[])
{
int fd;
uint off;
uint sz;
- int i;
if(argc > 2){
puts("Usage: ls [dir]\n");
if (argc == 2) {
fd = open(argv[1], 0);
if(fd < 0){
- printf(2, "ls: cannot open dir %s\n", argv[1]);
+ printf(2, "ls: cannot open %s\n", argv[1]);
exit();
}
} else {
printf(2, "ls: cannot stat dir\n");
exit();
}
- if (st.st_type != T_DIR) {
- printf(2, "ls: dir is not a directory\n");
- }
- sz = st.st_size;
- for(off = 0; off < sz; off += sizeof(struct dirent)) {
- if (read(fd, &dirent, sizeof(struct dirent)) != sizeof(struct dirent)) {
- printf(1, "ls: read error\n");
- break;
- }
- if (dirent.inum != 0) {
- // xxx prepend to name the pathname supplied to ls (e.g. .. in ls ..)
- if (stat (dirent.name, &st) < 0) {
- printf(1, "stat: failed %s\n", dirent.name);
- continue;
+
+ switch (st.st_type) {
+ case T_FILE:
+ pname(argv[1]);
+ printf(1, "%d %d %d\n", st.st_type, st.st_ino, st.st_size);
+ break;
+ case T_DIR:
+ sz = st.st_size;
+ for(off = 0; off < sz; off += sizeof(struct dirent)) {
+ if (read(fd, &dirent, sizeof(struct dirent)) != sizeof(struct dirent)) {
+ printf(1, "ls: read error\n");
+ break;
}
- for (i = 0; i < DIRSIZ; i++) {
- if (dirent.name[i] != '\0')
- printf(1, "%c", dirent.name[i]);
- else
- printf(1, " ");
+ if (dirent.inum != 0) {
+ // xxx prepend to name the pathname supplied to ls (e.g. .. in ls ..)
+ if (stat (dirent.name, &st) < 0) {
+ printf(1, "stat: failed %s\n", dirent.name);
+ continue;
+ }
+ pname(dirent.name);
+ printf(1, "%d %d %d\n", st.st_type, dirent.inum, st.st_size);
}
- printf(1, "%d %d %d\n", st.st_type, dirent.inum, st.st_size);
}
+ break;
}
close(fd);
-
exit();
}
#include "fs.h"
#include "fcntl.h"
-char *args[100];
-void parse(char buf[]);
+#define BUFSIZ 512
+#define MAXARGS 10
+#define MAXNODE 2
+
+// only allocate nodes for i/o redir; at some point we may have to build a
+// a real parse tree.
+struct node {
+ int token;
+ char *s;
+};
+struct node list[MAXNODE];
+int nextnode;
+
+char buf[BUFSIZ];
+char *argv[MAXARGS];
+char argv0buf[BUFSIZ];
+int argc;
+
+int debug = 1;
+
+int parse(char *s);
+void runcmd(void);
+int ioredirection(void);
+int gettoken(char *s, char **token);
+int _gettoken(char *s, char **p1, char **p2);
+void addnode(int token, char *s);
int
main(void)
{
- char buf[128];
- int pid;
-
while(1){
puts("$ ");
memset (buf, '\0', sizeof(buf));
gets(buf, sizeof(buf));
- if(buf[0] == '\0')
+ if (parse(buf) < 0)
continue;
- pid = fork();
- if(pid == 0){
- parse(buf);
- if (buf[0] == 'c' && buf[1] == 'd' && buf[2] == '\0') { // cd
- chdir(&buf[3]);
- } else {
- exec(buf, args);
- printf(1, "%s: not found\n", buf);
- exit();
+ runcmd();
+ }
+}
+
+int
+parse(char *s)
+{
+ char *t;
+ int c;
+
+ gettoken(s, 0);
+
+ argc = 0;
+ nextnode = 0;
+ while (1) {
+ switch ((c = gettoken(0, &t))) {
+
+ case 'w': // Add an argument
+ if (argc == MAXARGS) {
+ printf(2, "too many arguments\n");
+ return -1;
}
+ argv[argc++] = t;
+ break;
+
+ case '<': // Input redirection
+ // Grab the filename from the argument list
+ if (gettoken(0, &t) != 'w') {
+ printf(2, "syntax error: < not followed by word\n");
+ return -1;
+ }
+ addnode('<', t);
+ break;
+
+ case '>': // Output redirection
+ // Grab the filename from the argument list
+ if (gettoken(0, &t) != 'w') {
+ printf(2, "syntax error: > not followed by word\n");
+ return -1;
+ }
+ addnode('>', t);
+ break;
+
+ case 0: // String is complete
+ return 0;
+
+ default:
+ printf(2, "syntax error: bad return %d from gettoken", c);
+ return -1;
+
}
- if(pid > 0)
- wait();
}
}
+
void
-parse(char buf[])
+runcmd(void)
+{
+ int i, r, pid;
+
+ // Return immediately if command line was empty.
+ if(argc == 0) {
+ if (debug)
+ printf(2, "EMPTY COMMAND\n");
+ return;
+ }
+
+ // Clean up command line.
+ // Read all commands from the filesystem: add an initial '/' to
+ // the command name.
+ // This essentially acts like 'PATH=/'.
+ if (argv[0][0] != '/') {
+ argv0buf[0] = '/';
+ strcpy(argv0buf + 1, argv[0]);
+ argv[0] = argv0buf;
+ }
+ argv[argc] = 0;
+
+ // Print the command.
+ if (debug) {
+ printf(2, "[%d] SPAWN:", getpid());
+ for (i = 0; argv[i]; i++)
+ printf(2, " %s", argv[i]);
+ for (i = 0; i < nextnode; i++) {
+ printf(2, "%c %s", list[i].token, list[i].s);
+ }
+ printf(2, "\n");
+ }
+
+ if (strcmp(argv[0], "/cd") == 0) {
+ if (debug) printf (2, "/cd %s is build in\n", argv[1]);
+ chdir(argv[1]);
+ return;
+ }
+
+ pid = fork();
+ if (pid == 0) {
+ if (ioredirection() < 0)
+ exit();
+ if ((r = exec(argv0buf, (char**) argv)) < 0) {
+ printf(2, "exec %s: %d\n", argv[0], r);
+ exit();
+ }
+ }
+
+ if (pid > 0) {
+ if (debug)
+ printf(2, "[%d] WAIT %s\n", getpid(), argv[0]);
+ wait();
+ if (debug)
+ printf(2, "[%d] wait finished\n", getpid());
+ }
+}
+
+int
+ioredirection(void)
{
- int j = 1;
- int i;
- args[0] = buf;
- for (i = 0; buf[i] != '\0'; i++) {
- if (buf[i] == ' ') {
- buf[i] = '\0';
- args[j++] = buf + i + 1;
- if (j >= 100) {
- printf(2, "too many args\n");
+ int i, fd, dfd;
+
+ for (i = 0; i < nextnode; i++) {
+ switch (list[i].token) {
+ case '<':
+ if ((fd = open(list[i].s, O_RDONLY)) < 0) {
+ printf(2, "failed to open %s for read: %d", list[i].s, fd);
+ return -1;
+ }
+
+ if (debug)
+ printf(2, "redirect 0 from %s\n", list[i].s);
+
+ close(0);
+ if ((dfd = dup(fd)) < 0)
+ printf(2, "dup failed\n");
+ if (debug)
+ printf(2, "dup returns %d\n", dfd);
+ close(fd);
+ break;
+ case '>':
+ if ((fd = open(list[i].s, O_WRONLY|O_CREATE)) < 0) {
+ printf(2, "failed to open %s for write: %d", list[i].s, fd);
exit();
}
+
+ if (debug)
+ printf(2, "redirect 1 to %s\n", list[i].s);
+
+ if (close(1) < 0)
+ printf(2, "close 1 failed\n");
+ if ((dfd = dup(fd)) < 0)
+ printf(2, "dup failed\n");
+ if (debug)
+ printf(2, "dup returns %d\n", dfd);
+ close(fd);
+ break;
}
}
- args[j] = '\0';
+ return 0;
+}
+
+void
+addnode(int token, char *s)
+{
+ if (nextnode >= MAXNODE) {
+ printf(2, "addnode: ran out of nodes\n");
+ return;
+ }
+
+ list[nextnode].token = token;
+ list[nextnode].s = s;
+ nextnode++;
+}
+
+
+// gettoken(s, 0) prepares gettoken for subsequent calls and returns 0.
+// gettoken(0, token) parses a shell token from the previously set string,
+// null-terminates that token, stores the token pointer in '*token',
+// and returns a token ID (0, '<', '>', '|', or 'w').
+// Subsequent calls to 'gettoken(0, token)' will return subsequent
+// tokens from the string.
+
+int
+gettoken(char *s, char **p1)
+{
+ static int c, nc;
+ static char* np1, *np2;
+
+ if (s) {
+ nc = _gettoken(s, &np1, &np2);
+ return 0;
+ }
+ c = nc;
+ *p1 = np1;
+ nc = _gettoken(np2, &np1, &np2);
+ return c;
}
+
+
+// Get the next token from string s.
+// Set *p1 to the beginning of the token and *p2 just past the token.
+// Returns
+// 0 for end-of-string;
+// < for <;
+// > for >;
+// | for |;
+// w for a word.
+//
+// Eventually (once we parse the space where the \0 will go),
+// words get nul-terminated.
+#define WHITESPACE " \t\r\n"
+#define SYMBOLS "<|>&;()"
+
+int
+_gettoken(char *s, char **p1, char **p2)
+{
+ int t;
+
+ if (s == 0) {
+ if (debug > 1)
+ printf(2, "GETTOKEN NULL\n");
+ return 0;
+ }
+
+ if (debug > 1)
+ printf(2, "GETTOKEN: %s\n", s);
+
+ *p1 = 0;
+ *p2 = 0;
+
+ while (strchr(WHITESPACE, *s))
+ *s++ = 0;
+ if (*s == 0) {
+ if (debug > 1)
+ printf(2, "EOL\n");
+ return 0;
+ }
+ if (strchr(SYMBOLS, *s)) {
+ t = *s;
+ *p1 = s;
+ *s++ = 0;
+ *p2 = s;
+ if (debug > 1)
+ printf(2, "TOK %c\n", t);
+ return t;
+ }
+ *p1 = s;
+ while (*s && !strchr(WHITESPACE SYMBOLS, *s))
+ s++;
+ *p2 = s;
+ if (debug > 1) {
+ t = **p2;
+ **p2 = 0;
+ printf(2, "WORD: %s\n", *p1);
+ **p2 = t;
+ }
+ return 'w';
+}
+
projects / cs3210-lab1.git / commitdiff