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cosmopolitan/libc/stdio/cocmd.c
Justine Tunney b41f91c658
Greatly expand system() shell code features 
The cosmopolitan command interpreter now has 13 builtin commands,
variable support, support for ; / && / || syntax, asynchronous support,
and plenty of unit tests with bug fixes.

This change fixes a bug in posix_spawn() with null envp arg. strace
logging now uses atomic writes for scatter functions. Breaking change
renaming GetCpuCount() to _getcpucount(). TurfWar is now updated to use
the new token bucket algorithm. WIN32 affinity masks now inherit across
fork() and execve().
2022-10-11 21:30:31 -07:00

630 lines
16 KiB
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/stat.h"
#include "libc/calls/struct/timespec.h"
#include "libc/errno.h"
#include "libc/fmt/conv.h"
#include "libc/fmt/itoa.h"
#include "libc/fmt/magnumstrs.internal.h"
#include "libc/intrin/safemacros.internal.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/append.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/s.h"
#include "libc/sysv/consts/sig.h"
#include "libc/x/x.h"
#include "third_party/double-conversion/wrapper.h"
/**
* @fileoverview Cosmopolitan Command Interpreter
*
* This is a lightweight command interpreter for GNU Make. It has just
* enough shell script language support to support our build config.
*/
#define STATE_CMD 0
#define STATE_VAR 1
#define STATE_SINGLE 2
#define STATE_QUOTED 3
#define STATE_QUOTED_VAR 4
#define STATE_WHITESPACE 5
static char *p;
static char *q;
static int vari;
static size_t n;
static char *cmd;
static char var[32];
static int lastchild;
static int exitstatus;
static char *args[8192];
static const char *prog;
static char errbuf[512];
static char argbuf[ARG_MAX];
static bool unsupported[256];
static ssize_t Write(int fd, const char *s) {
return write(fd, s, strlen(s));
}
static void Log(const char *s, ...) {
va_list va;
va_start(va, s);
errbuf[0] = 0;
do {
strlcat(errbuf, s, sizeof(argbuf));
} while ((s = va_arg(va, const char *)));
strlcat(errbuf, "\n", sizeof(argbuf));
Write(2, errbuf);
va_end(va);
}
static wontreturn void Wexit(int rc, const char *s, ...) {
va_list va;
va_start(va, s);
errbuf[0] = 0;
do {
strlcat(errbuf, s, sizeof(argbuf));
} while ((s = va_arg(va, const char *)));
Write(2, errbuf);
va_end(va);
_Exit(rc);
}
static wontreturn void UnsupportedSyntax(unsigned char c) {
char cbuf[2];
char ibuf[13];
cbuf[0] = c;
cbuf[1] = 0;
FormatOctal32(ibuf, c, true);
Wexit(4, prog, ": unsupported shell syntax '", cbuf, "' (", ibuf, "): ", cmd,
"\n", 0);
}
static wontreturn void SysExit(int rc, const char *call, const char *thing) {
int err;
char ibuf[12];
const char *estr;
err = errno;
FormatInt32(ibuf, err);
estr = _strerdoc(err);
if (!estr) estr = "EUNKNOWN";
Wexit(rc, thing, ": ", call, "() failed: ", estr, " (", ibuf, ")\n", 0);
}
static void Open(const char *path, int fd, int flags) {
const char *err;
close(fd);
if (open(path, flags, 0644) == -1) {
SysExit(7, "open", path);
}
}
static wontreturn void Exec(void) {
_npassert(args[0][0]);
if (!n) Wexit(5, prog, ": error: too few args\n", 0);
execvp(args[0], args);
SysExit(127, "execve", args[0]);
}
static int GetSignalByName(const char *s) {
for (int i = 0; kSignalNames[i].x != MAGNUM_TERMINATOR; ++i) {
if (!strcmp(s, MAGNUM_STRING(kSignalNames, i) + 3)) {
return MAGNUM_NUMBER(kSignalNames, i);
}
}
return 0;
}
static int True(void) {
return 0;
}
static int False(void) {
return 1;
}
static wontreturn void Exit(void) {
_Exit(n > 1 ? atoi(args[1]) : 0);
}
static int Wait(void) {
char ibuf[12];
int e, rc, ws, pid;
if (n > 1) {
if (waitpid(atoi(args[1]), &ws, 0) == -1) {
SysExit(22, "waitpid", prog);
}
rc = WIFEXITED(ws) ? WEXITSTATUS(ws) : 128 + WTERMSIG(ws);
exitstatus = rc;
} else {
for (e = errno;;) {
if (waitpid(-1, &ws, 0) == -1) {
if (errno == ECHILD) {
errno = e;
break;
}
SysExit(22, "waitpid", prog);
}
}
rc = 0;
}
return rc;
}
static int Echo(void) {
int i = 1;
bool once = false;
const char *l = " ";
if (i < n && !strcmp(args[i], "-l")) {
++i, l = "\n";
}
for (; i < n; ++i) {
if (once) {
Write(1, l);
} else {
once = true;
}
Write(1, args[i]);
}
Write(1, "\n");
return 0;
}
static int Read(void) {
char *b = 0;
unsigned char c;
int a = 1, rc = 1;
if (n >= 3 && !strcmp(args[1], "-p")) {
Write(1, args[2]);
a = 3;
}
appendr(&b, 0);
while (read(0, &c, 1) > 0) {
if (c == '\n') {
rc = 0;
break;
}
appendw(&b, c);
}
if (a < n) {
setenv(args[1], b, true);
}
free(b);
return rc;
}
static int Cd(void) {
const char *s = n > 1 ? args[1] : getenv("HOME");
if (s) {
if (!chdir(s)) {
return 0;
} else {
Log("chdir: ", s, ": ", _strerdoc(errno), 0);
return 1;
}
} else {
Log("chdir: missing argument", 0);
return 1;
}
}
static int Mkdir(void) {
int i = 1;
int (*f)(const char *, unsigned) = mkdir;
if (n >= 3 && !strcmp(args[1], "-p")) ++i, f = makedirs;
for (; i < n; ++i) {
if (f(args[i], 0755)) {
Log("mkdir: ", args[i], ": ", _strerdoc(errno), 0);
return errno;
}
}
return 0;
}
static int Kill(void) {
int sig, rc = 0, i = 1;
if (i < n && args[i][0] == '-') {
sig = GetSignalByName(args[i++] + 1);
if (!sig) return 1;
} else {
sig = SIGTERM;
}
for (; i < n; ++i) {
if (kill(atoi(args[i]), sig)) {
Log("kill: ", args[i], ": ", _strerdoc(errno), 0);
rc = 1;
}
}
return rc;
}
static int Toupper(void) {
int i, n;
char b[512];
while ((n = read(0, b, 512)) > 0) {
for (i = 0; i < n; ++i) {
b[i] = toupper(b[i]);
}
write(1, b, n);
}
return 0;
}
static int Usleep(void) {
struct timespec t, *p = 0;
if (n > 1) {
t = _timespec_frommicros(atoi(args[1]));
p = &t;
}
return clock_nanosleep(0, 0, p, 0);
}
static int Test(void) {
struct stat st;
if (n && !strcmp(args[n - 1], "]")) --n;
if (n == 4 && !strcmp(args[2], "=")) {
return !!strcmp(args[1], args[3]);
} else if (n == 4 && !strcmp(args[2], "!=")) {
return !strcmp(args[1], args[3]);
} else if (n == 3 && !strcmp(args[1], "-n")) {
return !(strlen(args[2]) > 0);
} else if (n == 3 && !strcmp(args[1], "-z")) {
return !(strlen(args[2]) == 0);
} else if (n == 3 && !strcmp(args[1], "-e")) {
return !!stat(args[2], &st);
} else if (n == 3 && !strcmp(args[1], "-f")) {
return !stat(args[2], &st) && S_ISREG(st.st_mode);
} else if (n == 3 && !strcmp(args[1], "-d")) {
return !stat(args[2], &st) && S_ISDIR(st.st_mode);
} else if (n == 3 && !strcmp(args[1], "-h")) {
return !stat(args[2], &st) && S_ISLNK(st.st_mode);
} else {
return 1;
}
}
static int TryBuiltin(void) {
if (!n) return 0;
if (!strcmp(args[0], "exit")) Exit();
if (!strcmp(args[0], "cd")) return Cd();
if (!strcmp(args[0], "[")) return Test();
if (!strcmp(args[0], "wait")) return Wait();
if (!strcmp(args[0], "echo")) return Echo();
if (!strcmp(args[0], "read")) return Read();
if (!strcmp(args[0], "true")) return True();
if (!strcmp(args[0], "test")) return Test();
if (!strcmp(args[0], "kill")) return Kill();
if (!strcmp(args[0], "mkdir")) return Mkdir();
if (!strcmp(args[0], "false")) return False();
if (!strcmp(args[0], "usleep")) return Usleep();
if (!strcmp(args[0], "toupper")) return Toupper();
return -1;
}
static wontreturn void Launch(void) {
int rc;
if ((rc = TryBuiltin()) != -1) _Exit(rc);
Exec();
}
static void Pipe(void) {
int pid, pfds[2];
if (pipe2(pfds, O_CLOEXEC)) SysExit(8, "pipe2", prog);
if ((pid = fork()) == -1) SysExit(9, "vfork", prog);
if (!pid) {
_unassert(dup2(pfds[1], 1) == 1);
// we can't rely on cloexec because builtins
if (pfds[0] != 1) _unassert(!close(pfds[0]));
if (pfds[1] != 1) _unassert(!close(pfds[1]));
Launch();
}
_unassert(!dup2(pfds[0], 0));
if (pfds[1]) _unassert(!close(pfds[1]));
n = 0;
}
static int Run(void) {
int exitstatus, ws, pid;
if ((exitstatus = TryBuiltin()) == -1) {
if ((pid = vfork()) == -1) SysExit(21, "vfork", prog);
if (!pid) Exec();
if (waitpid(pid, &ws, 0) == -1) SysExit(22, "waitpid", prog);
exitstatus = WIFEXITED(ws) ? WEXITSTATUS(ws) : 128 + WTERMSIG(ws);
}
n = 0;
return exitstatus;
}
static void Async(void) {
if ((lastchild = fork()) == -1) SysExit(21, "vfork", prog);
if (!lastchild) Launch();
n = 0;
}
static const char *IntToStr(int x) {
static char ibuf[12];
FormatInt32(ibuf, x);
return ibuf;
}
static const char *GetEnv(const char *key) {
if (key[0] == '$' && !key[1]) {
return IntToStr(getpid());
} else if (key[0] == '!' && !key[1]) {
return IntToStr(lastchild);
} else if (key[0] == '?' && !key[1]) {
return IntToStr(exitstatus);
} else {
return getenv(key);
}
}
static bool IsVarName(int c) {
return isalnum(c) || c == '_' ||
(!vari && (c == '?' || c == '!' || c == '$'));
}
static inline void Append(int c) {
_unassert(q + 1 < argbuf + sizeof(argbuf));
*q++ = c;
}
static char *Tokenize(void) {
char *r;
const char *s;
int c, t, j, k, rc;
for (r = q, t = STATE_WHITESPACE;; ++p) {
switch (t) {
case STATE_WHITESPACE:
if (!*p) return 0;
if (*p == ' ' || *p == '\t' || *p == '\n' ||
(p[0] == '\\' && p[1] == '\n')) {
continue;
}
t = STATE_CMD;
// fallthrough
case STATE_CMD:
if (unsupported[*p & 255]) {
UnsupportedSyntax(*p);
}
if (!*p || *p == ' ' || *p == '\t') {
Append(0);
return r;
} else if (*p == '"') {
t = STATE_QUOTED;
} else if (*p == '\'') {
t = STATE_SINGLE;
} else if (*p == '$') {
t = STATE_VAR;
var[(vari = 0)] = 0;
} else if (*p == '\\') {
if (!p[1]) UnsupportedSyntax(*p);
Append(*++p);
} else if (*p == '|') {
if (q > r) {
Append(0);
return r;
} else if (p[1] == '|') {
rc = Run();
if (!rc) {
_Exit(0);
} else {
++p;
t = STATE_WHITESPACE;
}
} else {
Pipe();
t = STATE_WHITESPACE;
}
} else if (*p == ';') {
if (q > r) {
Append(0);
return r;
} else {
Run();
t = STATE_WHITESPACE;
}
} else if (*p == '&') {
if (q > r) {
Append(0);
return r;
} else if (p[1] == '&') {
rc = Run();
if (!rc) {
++p;
t = STATE_WHITESPACE;
} else {
_Exit(rc);
}
} else {
Async();
t = STATE_WHITESPACE;
}
} else {
Append(*p);
}
break;
case STATE_VAR:
if (IsVarName(*p)) {
_unassert(vari + 1 < sizeof(var));
var[vari++] = *p;
var[vari] = 0;
} else {
// XXX: we need to find a simple elegant way to break up
// unquoted variable expansions into multiple args.
if ((s = GetEnv(var))) {
if ((j = strlen(s))) {
_unassert(q + j < argbuf + sizeof(argbuf));
q = mempcpy(q, s, j);
}
}
--p;
t = STATE_CMD;
}
break;
case STATE_SINGLE:
if (!*p) goto UnterminatedString;
if (*p == '\'') {
t = STATE_CMD;
} else {
*q++ = *p;
}
break;
UnterminatedString:
Wexit(6, "cmd: error: unterminated string\n", 0);
case STATE_QUOTED:
if (!*p) goto UnterminatedString;
if (*p == '"') {
t = STATE_CMD;
} else if (p[0] == '$') {
t = STATE_QUOTED_VAR;
var[(vari = 0)] = 0;
} else if (p[0] == '\\') {
switch ((c = *++p)) {
case 0:
UnsupportedSyntax('\\');
case '\n':
break;
case '$':
case '`':
case '"':
*q++ = c;
break;
default:
*q++ = '\\';
*q++ = c;
break;
}
} else {
*q++ = *p;
}
break;
case STATE_QUOTED_VAR:
if (!*p) goto UnterminatedString;
if (IsVarName(*p)) {
_unassert(vari + 1 < sizeof(var));
var[vari++] = *p;
var[vari] = 0;
} else {
if ((s = GetEnv(var))) {
if ((j = strlen(s))) {
_unassert(q + j < argbuf + sizeof(argbuf));
q = mempcpy(q, s, j);
}
}
--p;
t = STATE_QUOTED;
}
break;
default:
unreachable;
}
}
}
static const char *GetRedirectArg(const char *prog, const char *arg, int n) {
if (arg[n]) {
return arg + n;
} else if ((arg = Tokenize())) {
return arg;
} else {
Wexit(14, prog, ": error: redirect missing path\n", 0);
}
}
int cocmd(int argc, char *argv[]) {
char *arg;
size_t i, j;
prog = argc > 0 ? argv[0] : "cocmd.com";
for (i = 1; i < 32; ++i) {
unsupported[i] = true;
}
unsupported['\t'] = false;
unsupported[0177] = true;
unsupported['~'] = true;
unsupported['`'] = true;
unsupported['#'] = true;
unsupported['*'] = true;
unsupported['('] = true;
unsupported[')'] = true;
unsupported['{'] = true;
unsupported['}'] = true;
unsupported['?'] = true;
if (argc != 3) {
Wexit(10, prog, ": error: wrong number of args\n", 0);
}
if (strcmp(argv[1], "-c")) {
Wexit(11, prog, ": error: argv[1] should -c\n", 0);
}
p = cmd = argv[2];
if (strlen(cmd) >= ARG_MAX) {
Wexit(12, prog, ": error: cmd too long: ", cmd, "\n", 0);
}
n = 0;
q = argbuf;
while ((arg = Tokenize())) {
if (n + 1 < ARRAYLEN(args)) {
if (isdigit(arg[0]) && arg[1] == '>' && arg[2] == '&' &&
isdigit(arg[3])) {
dup2(arg[3] - '0', arg[0] - '0');
} else if (arg[0] == '>' && arg[1] == '&' && isdigit(arg[2])) {
dup2(arg[2] - '0', 1);
} else if (isdigit(arg[0]) && arg[1] == '>' && arg[2] == '>') {
Open(GetRedirectArg(prog, arg, 3), arg[0] - '0',
O_WRONLY | O_CREAT | O_APPEND);
} else if (arg[0] == '>' && arg[1] == '>') {
Open(GetRedirectArg(prog, arg, 2), 1, O_WRONLY | O_CREAT | O_APPEND);
} else if (isdigit(arg[0]) && arg[1] == '>') {
Open(GetRedirectArg(prog, arg, 2), arg[0] - '0',
O_WRONLY | O_CREAT | O_TRUNC);
} else if (arg[0] == '>') {
Open(GetRedirectArg(prog, arg, 1), 1, O_WRONLY | O_CREAT | O_TRUNC);
} else if (arg[0] == '<') {
Open(GetRedirectArg(prog, arg, 1), 0, O_RDONLY);
} else {
args[n++] = arg;
args[n] = 0;
}
} else {
Wexit(13, prog, ": error: too many args\n", 0);
}
}
Launch();
}
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