From: Denis Vlasenko Date: Mon, 11 Feb 2008 18:10:06 +0000 (-0000) Subject: msh: do not run pipes where last command is a builtin X-Git-Tag: 1_10_0~193 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=a5f2cd30c9308b3cec359acdf79d60958d6d5834;p=oweals%2Fbusybox.git msh: do not run pipes where last command is a builtin msh: code shrink and some renames for better readability --- diff --git a/shell/msh.c b/shell/msh.c index 531ae779a..f05028f26 100644 --- a/shell/msh.c +++ b/shell/msh.c @@ -2553,8 +2553,7 @@ static int execute(struct op *t, int *pin, int *pout, int act) interactive = hinteractive; if (i != -1) { setval(lookup("!"), putn(i)); - if (pin != NULL) - closepipe(pin); + closepipe(pin); if (interactive) { prs(putn(i)); prs("\n"); @@ -2689,8 +2688,8 @@ static builtin_func_ptr inbuilt(const char *s) static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) { pid_t newpid; - int i, rv; - builtin_func_ptr shcom = NULL; + int i; + builtin_func_ptr bltin = NULL; int f; const char *cp = NULL; struct ioword **iopp; @@ -2711,7 +2710,7 @@ static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) (void) &pin; (void) &pout; (void) ℘ - (void) &shcom; + (void) &bltin; (void) &cp; (void) &resetsig; (void) &owp; @@ -2724,7 +2723,6 @@ static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) owp = wp; resetsig = 0; - rv = -1; /* system-detected error */ if (t->type == TCOM) { while (*wp++ != NULL) continue; @@ -2745,17 +2743,17 @@ static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) return setstatus(0); } if (cp != NULL) { - shcom = inbuilt(cp); + bltin = inbuilt(cp); } } t->words = wp; f = act; - DBGPRINTF(("FORKEXEC: shcom %p, f&FEXEC 0x%x, owp %p\n", shcom, + DBGPRINTF(("FORKEXEC: bltin %p, f&FEXEC 0x%x, owp %p\n", bltin, f & FEXEC, owp)); - if (shcom == NULL && (f & FEXEC) == 0) { + if (!bltin && (f & FEXEC) == 0) { /* Save values in case the child process alters them */ hpin = pin; hpout = pout; @@ -2783,18 +2781,13 @@ static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) intr = hintr; brklist = hbrklist; execflg = hexecflg; -/* moved up - if (i == -1) - return rv; -*/ - if (pin != NULL) - closepipe(pin); + closepipe(pin); return (pout == NULL ? setstatus(waitfor(newpid, 0)) : 0); } - /* Must be the child process, pid should be 0 */ - DBGPRINTF(("FORKEXEC: child process, shcom=%p\n", shcom)); + /* Child */ + DBGPRINTF(("FORKEXEC: child process, bltin=%p\n", bltin)); if (interactive) { signal(SIGINT, SIG_IGN); @@ -2808,13 +2801,18 @@ static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) execflg = 0; } - if (owp != NULL) + if (owp) while ((cp = *owp++) != NULL && assign(cp, COPYV)) - if (shcom == NULL) + if (!bltin) export(lookup(cp)); -#ifdef COMPIPE - if ((pin != NULL || pout != NULL) && shcom != NULL && shcom != doexec) { +#if 1 + /* How to fix it: + * explicitly pass pin[0] and pout[1] to builtins + * instead of making them rely on fd 0/1, + * and do not xmove_fd(pin[0]/pout[1]) below if bltin != NULL. + */ + if ((pin || pout) && bltin && bltin != doexec) { err("piping to/from shell builtins not yet done"); if (forked) _exit(-1); @@ -2822,20 +2820,20 @@ static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) } #endif - if (pin != NULL) { + if (pin) { xmove_fd(pin[0], 0); if (pin[1] != 0) close(pin[1]); } - if (pout != NULL) { + if (pout) { xmove_fd(pout[1], 1); - if (pout[1] != 1) + if (pout[0] > 1) close(pout[0]); } iopp = t->ioact; - if (iopp != NULL) { - if (shcom != NULL && shcom != doexec) { + if (iopp) { + if (bltin && bltin != doexec) { prs(cp); err(": cannot redirect shell command"); if (forked) @@ -2844,17 +2842,25 @@ static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) } while (*iopp) if (iosetup(*iopp++, pin != NULL, pout != NULL)) { + /* system-detected error */ if (forked) - _exit(rv); - return rv; + _exit(-1); + return -1; } } - if (shcom) { - i = setstatus((*shcom) (t)); + if (bltin) { + i = setstatus(bltin(t)); if (forked) _exit(i); DBGPRINTF(("FORKEXEC: returning i=%d\n", i)); +/* Builtins in pipes ("ls /dev/null | cd"): + * here "cd" (which is not a child) will return to main msh, + * and we will read from ls's output as if it is our next command! + * Result: "/dev/null: cannot execute" + * and then we reach EOF on stdin and exit. + * See above for possible way to fix this. + */ return i; } @@ -2882,7 +2888,7 @@ static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp) leave(); /* NOTREACHED */ - _exit(1); + return 0; } /* @@ -3056,7 +3062,7 @@ static const char *rexecve(char *c, char **v, char **envp) int i; const char *sp; char *tp; - int eacces = 0, asis = 0; + int asis = 0; char *name = c; if (ENABLE_FEATURE_SH_STANDALONE) { @@ -3104,10 +3110,6 @@ static const char *rexecve(char *c, char **v, char **envp) case E2BIG: return "argument list too long"; - - case EACCES: - eacces++; - break; } } return errno == ENOENT ? "not found" : "cannot execute"; @@ -3280,8 +3282,7 @@ static int doumask(struct op *t) fputc('0' + ((i >> n) & 07), stderr); fputc('\n', stderr); } else { -/* huh??? '8','9' are not allowed! */ - for (n = 0; *cp >= '0' && *cp <= '9'; cp++) + for (n = 0; *cp >= '0' && *cp <= '7'; cp++) n = n * 8 + (*cp - '0'); umask(n); } @@ -4618,7 +4619,6 @@ static int readc(void) DBGPRINTF(("READC: leave()...\n")); leave(); - /* NOTREACHED */ return 0; } @@ -4629,7 +4629,6 @@ static void ioecho(char c) write(2, &c, sizeof c); } - static void pushio(struct ioarg *argp, int (*fn) (struct ioarg *)) { DBGPRINTF(("PUSHIO: argp %p, argp->afid 0x%x, global_env.iop %p\n", argp, @@ -4967,8 +4966,8 @@ static int openpipe(int *pv) static void closepipe(int *pv) { if (pv != NULL) { - close(*pv++); - close(*pv); + close(pv[0]); + close(pv[1]); } }