get precedence of <, >, and | right
simplify
This commit is contained in:
kaashoek
parent
1133b215d8
commit
e00baa9f5d
2
main.c
2
main.c
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@ -78,7 +78,7 @@ main0(void)
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// enable interrupts on the local APIC
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lapic_enableintr();
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// Enable interrupts on this processor.
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// enable interrupts on this processor.
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cpus[cpu()].nlock--;
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sti();
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110
sh.c
110
sh.c
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@ -16,27 +16,26 @@ struct ionode {
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int token;
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char *s;
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};
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struct ionode iolist[MAXNODE];
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int nextio;
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struct cmd {
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char *argv[MAXARGS];
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char argv0buf[BUFSIZ];
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int argc;
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int token;
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struct ionode iolist[MAXNODE];
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struct ionode *io;
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};
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struct cmd cmdlist[MAXCMD];
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int nextcmd;
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struct cmd *cmd;
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char buf[BUFSIZ];
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int debug = 0;
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int parse(char *s);
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void runcmd(void);
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int ioredirection(void);
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int ioredirection(struct ionode *iolist, int nio);
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int gettoken(char *s, char **token);
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int _gettoken(char *s, char **p1, char **p2);
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void addio(int token, char *s);
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int
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main(void)
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@ -59,21 +58,21 @@ parse(char *s)
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gettoken(s, 0);
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nextio = 0;
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nextcmd = 0;
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cmd = &cmdlist[0];;
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for(i = 0; i < MAXCMD; i++) {
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cmdlist[i].argc = 0;
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cmdlist[i].token = 0;
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cmdlist[i].io = cmdlist[i].iolist;
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}
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while(1) {
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switch((c = gettoken(0, &t))) {
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case 'w': // Add an argument
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if(cmdlist[nextcmd].argc >= MAXARGS) {
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if(cmd->argc >= MAXARGS) {
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printf(2, "too many arguments\n");
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return -1;
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}
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cmdlist[nextcmd].argv[cmdlist[nextcmd].argc++] = t;
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cmd->argv[cmd->argc++] = t;
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break;
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case '<': // Input redirection
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@ -82,7 +81,9 @@ parse(char *s)
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printf(2, "syntax error: < not followed by word\n");
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return -1;
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}
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addio('<', t);
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cmd->io->token = '<';
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cmd->io->s = t;
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cmd->io++;
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break;
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case '>': // Output redirection
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@ -91,13 +92,15 @@ parse(char *s)
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printf(2, "syntax error: > not followed by word\n");
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return -1;
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}
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addio('>', t);
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cmd->io->token = '>';
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cmd->io->s = t;
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cmd->io++;
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break;
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case ';': // command sequence
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case '|': // pipe
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cmdlist[nextcmd].token = c;
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nextcmd++;
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cmd->token = c;
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cmd++;
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break;
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case 0: // String is complete
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@ -115,8 +118,10 @@ parse(char *s)
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void
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runcmd(void)
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{
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int c, i, r, pid, tfd;
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int i, r, pid, tfd;
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int fdarray[2];
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struct cmd *c;
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struct ionode *io;
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// Return immediately if command line was empty.
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if(cmdlist[0].argc == 0) {
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@ -125,43 +130,43 @@ runcmd(void)
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return;
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}
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for(c = 0; c <= nextcmd; c++) {
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for(c = &cmdlist[0]; c <= cmd; c++) {
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// Clean up command line.
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// Read all commands from the filesystem: add an initial '/' to
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// the command name.
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// This essentially acts like 'PATH=/'.
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if(cmdlist[c].argv[0][0] != '/') {
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cmdlist[c].argv0buf[0] = '/';
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strcpy(cmdlist[c].argv0buf + 1, cmdlist[c].argv[0]);
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cmdlist[c].argv[0] = cmdlist[c].argv0buf;
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if(c->argv[0][0] != '/') {
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c->argv0buf[0] = '/';
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strcpy(c->argv0buf + 1, c->argv[0]);
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c->argv[0] = c->argv0buf;
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}
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cmdlist[c].argv[cmdlist[c].argc] = 0;
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c->argv[c->argc] = 0;
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// Print the command.
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if(debug) {
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printf(2, "[%d] SPAWN:", getpid());
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for(i = 0; cmdlist[c].argv[i]; i++)
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printf(2, " %s", cmdlist[c].argv[i]);
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for(i = 0; i < nextio; i++) {
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printf(2, "%c %s", iolist[i].token, iolist[i].s);
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for(i = 0; c->argv[i]; i++)
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printf(2, " %s", c->argv[i]);
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for(io = c->iolist; io <= c->io; io++) {
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printf(2, "%c %s", io->token, io->s);
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}
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printf(2, "\n");
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}
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if(strcmp(cmdlist[c].argv[0], "/cd") == 0) {
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if(strcmp(c->argv[0], "/cd") == 0) {
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if(debug)
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printf (2, "/cd %s is build in\n", cmdlist[c].argv[1]);
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chdir(cmdlist[c].argv[1]);
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printf (2, "/cd %s is build in\n", c->argv[1]);
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chdir(c->argv[1]);
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return;
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}
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if(cmdlist[c].token == '|')
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if(c->token == '|')
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if(pipe(fdarray) < 0)
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printf(2, "cmd %d pipe failed\n", c);
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pid = fork();
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if(pid == 0) {
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if(cmdlist[c].token == '|') {
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if(c->token == '|') {
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if(close(1) < 0)
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printf(2, "close 1 failed\n");
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if((tfd = dup(fdarray[1])) < 0)
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@ -171,7 +176,7 @@ runcmd(void)
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if(close(fdarray[1]) < 0)
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printf(2, "close fdarray[1] failed\n");
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}
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if(c > 0 && cmdlist[c-1].token == '|') {
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if(c > cmdlist && (c-1)->token == '|') {
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if(close(0) < 0)
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printf(2, "close 0 failed\n");
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if((tfd = dup(fdarray[0])) < 0)
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@ -181,10 +186,10 @@ runcmd(void)
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if(close(fdarray[1]) < 0)
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printf(2, "close fdarray[1] failed\n");
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}
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if(ioredirection() < 0)
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if(ioredirection(c->iolist, c->io - c->iolist) < 0)
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exit();
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if((r = exec(cmdlist[c].argv0buf, (char**) cmdlist[c].argv)) < 0) {
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printf(2, "exec %s: %d\n", cmdlist[c].argv[0], r);
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if((r = exec(c->argv0buf, (char**) c->argv)) < 0) {
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printf(2, "exec %s: %d\n", c->argv[0], r);
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exit();
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}
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} else if(pid > 0) {
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@ -192,11 +197,11 @@ runcmd(void)
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if(debug)
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printf(2, "[%d] FORKED child %d\n", getpid(), pid);
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if(c > 0 && cmdlist[c-1].token == '|') {
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if(c > cmdlist && (c-1)->token == '|') {
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close(fdarray[0]);
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close(fdarray[1]);
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}
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if(cmdlist[c].token != '|') {
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if(c->token != '|') {
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if(debug)
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printf(2, "[%d] WAIT for children\n", getpid());
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do {
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@ -212,51 +217,38 @@ runcmd(void)
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}
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int
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ioredirection(void)
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ioredirection(struct ionode *iolist, int nio)
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{
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int i, fd;
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int fd;
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struct ionode *io;
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for(i = 0; i < nextio; i++) {
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switch(iolist[i].token) {
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for(io = iolist; io < &iolist[nio]; io++) {
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switch(io->token) {
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case '<':
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if(close(0) < 0)
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printf(2, "close 0 failed\n");
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if((fd = open(iolist[i].s, O_RDONLY)) < 0) {
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printf(2, "failed to open %s for read: %d", iolist[i].s, fd);
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if((fd = open(io->s, O_RDONLY)) < 0) {
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printf(2, "failed to open %s for read: %d", io->s, fd);
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return -1;
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}
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if(debug)
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printf(2, "redirect 0 from %s\n", iolist[i].s);
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printf(2, "redirect 0 from %s\n", io->s);
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break;
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case '>':
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if(close(1) < 0)
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printf(2, "close 1 failed\n");
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if((fd = open(iolist[i].s, O_WRONLY|O_CREATE)) < 0) {
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printf(2, "failed to open %s for write: %d", iolist[i].s, fd);
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if((fd = open(io->s, O_WRONLY|O_CREATE)) < 0) {
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printf(2, "failed to open %s for write: %d", io->s, fd);
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exit();
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}
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if(debug)
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printf(2, "redirect 1 to %s\n", iolist[i].s);
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printf(2, "redirect 1 to %s\n", io->s);
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break;
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}
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}
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return 0;
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}
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void
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addio(int token, char *s)
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{
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if(nextio >= MAXNODE) {
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printf(2, "addio: ran out of nodes\n");
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return;
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}
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iolist[nextio].token = token;
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iolist[nextio].s = s;
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nextio++;
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}
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// gettoken(s, 0) prepares gettoken for subsequent calls and returns 0.
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// gettoken(0, token) parses a shell token from the previously set string,
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// null-terminates that token, stores the token pointer in '*token',
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