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get precedence of <, >, and | right

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simplify
This commit is contained in:
kaashoek 2006-09-07 02:15:28 +00:00
parent 1133b215d8
commit e00baa9f5d
2 changed files with 52 additions and 60 deletions
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2
main.c
View file

@ -78,7 +78,7 @@ main0(void)
// enable interrupts on the local APIC // enable interrupts on the local APIC
lapic_enableintr(); lapic_enableintr();
// Enable interrupts on this processor. // enable interrupts on this processor.
cpus[cpu()].nlock--; cpus[cpu()].nlock--;
sti(); sti();

110
sh.c
View file

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