From 950a1b310b8389c18f6d5fe1cee38a53dd8149b4 Mon Sep 17 00:00:00 2001 From: Justine Tunney Date: Sun, 2 Oct 2022 15:29:57 -0700 Subject: [PATCH] Embed cocmd.com interpreter for system() / open() This change lets you use system() in an easier and portable way. The problem with the call in the past has always been that bourne and cmd.com on Windows have less than nothing in common, so pretty much the only command system() could be used for across platforms was maybe echo. cmd.exe is also a security liability due to its escaping rules. Since cocmd.com implements 85% of what we need from bourne, in a really tiny way, it makes perfect sense to be embedded in these functionss. We get a huge performance boost too. Fixes #644 --- libc/intrin/_PATH_BSHELL.c | 21 --- libc/paths.h | 9 +- libc/stdio/cocmd.c | 270 ++++++++++++++++++++++++++++++++++ libc/stdio/cocmd.internal.h | 10 ++ libc/stdio/popen.c | 10 ++ libc/stdio/system.c | 18 +-- libc/stdio/systemexec.c | 28 +--- test/libc/stdio/system_test.c | 16 +- tool/build/cocmd.c | 251 +------------------------------ 9 files changed, 313 insertions(+), 320 deletions(-) delete mode 100644 libc/intrin/_PATH_BSHELL.c create mode 100644 libc/stdio/cocmd.c create mode 100644 libc/stdio/cocmd.internal.h diff --git a/libc/intrin/_PATH_BSHELL.c b/libc/intrin/_PATH_BSHELL.c deleted file mode 100644 index 1d9d80de2..000000000 --- a/libc/intrin/_PATH_BSHELL.c +++ /dev/null @@ -1,21 +0,0 @@ -/*-*- 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/paths.h" - -const char *_PATH_BSHELL = "/bin/sh"; diff --git a/libc/paths.h b/libc/paths.h index 7f6b2ca7e..ecdffd9ba 100644 --- a/libc/paths.h +++ b/libc/paths.h @@ -1,17 +1,10 @@ #ifndef COSMOPOLITAN_LIBC_PATHS_H_ #define COSMOPOLITAN_LIBC_PATHS_H_ -#if !(__ASSEMBLER__ + __LINKER__ + 0) -COSMOPOLITAN_C_START_ - -extern const char *_PATH_BSHELL; - -COSMOPOLITAN_C_END_ -#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */ #define _PATH_DEFPATH "/usr/local/bin:/bin:/usr/bin" #define _PATH_STDPATH "/bin:/usr/bin:/sbin:/usr/sbin" -#define _PATH_BSHELL _PATH_BSHELL +#define _PATH_BSHELL "/bin/sh" #define _PATH_CONSOLE "/dev/console" #define _PATH_DEVNULL "/dev/null" #define _PATH_KLOG "/proc/kmsg" diff --git a/libc/stdio/cocmd.c b/libc/stdio/cocmd.c new file mode 100644 index 000000000..a7cea9440 --- /dev/null +++ b/libc/stdio/cocmd.c @@ -0,0 +1,270 @@ +/*-*- 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/calls/calls.h" +#include "libc/errno.h" +#include "libc/fmt/itoa.h" +#include "libc/macros.internal.h" +#include "libc/mem/mem.h" +#include "libc/runtime/runtime.h" +#include "libc/stdio/stdio.h" +#include "libc/str/str.h" +#include "libc/sysv/consts/o.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_SHELL 0 +#define STATE_STR 1 +#define STATE_QUO 2 + +char *p; +char *q; +size_t n; +char *cmd; +char *args[8192]; +const char *prog; +char argbuf[ARG_MAX]; +bool unsupported[256]; + +void Write(const char *s, ...) { + va_list va; + va_start(va, s); + do { + write(2, s, strlen(s)); + } while ((s = va_arg(va, const char *))); + va_end(va); +} + +wontreturn void UnsupportedSyntax(unsigned char c) { + char cbuf[2]; + char ibuf[13]; + cbuf[0] = c; + cbuf[1] = 0; + FormatOctal32(ibuf, c, true); + Write(prog, ": unsupported shell syntax '", cbuf, "' (", ibuf, "): ", cmd, + "\n", 0); + exit(4); +} + +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"; + Write(thing, ": ", call, "() failed: ", estr, " (", ibuf, ")\n", 0); + exit(rc); +} + +void Open(const char *path, int fd, int flags) { + const char *err; + close(fd); + if (open(path, flags, 0644) == -1) { + SysExit(7, "open", path); + } +} + +wontreturn void Exec(void) { + const char *s; + if (!n) { + Write(prog, ": error: too few args\n", 0); + exit(5); + } + execv(args[0], args); + SysExit(127, "execve", args[0]); +} + +void Pipe(void) { + int pid, pfds[2]; + if (pipe2(pfds, O_CLOEXEC)) { + SysExit(8, "pipe2", prog); + } + if ((pid = vfork()) == -1) { + SysExit(9, "vfork", prog); + } + if (!pid) { + dup2(pfds[1], 1); + Exec(); + } + dup2(pfds[0], 0); + n = 0; +} + +char *Tokenize(void) { + char *r; + int c, t; + while (*p == ' ' || *p == '\t' || *p == '\n' || + (p[0] == '\\' && p[1] == '\n')) { + ++p; + } + if (!*p) return 0; + t = STATE_SHELL; + for (r = q;; ++p) { + switch (t) { + + case STATE_SHELL: + if (unsupported[*p & 255]) { + UnsupportedSyntax(*p); + } + if (!*p || *p == ' ' || *p == '\t') { + *q++ = 0; + return r; + } else if (*p == '"') { + t = STATE_QUO; + } else if (*p == '\'') { + t = STATE_STR; + } else if (*p == '\\') { + if (!p[1]) UnsupportedSyntax(*p); + *q++ = *++p; + } else if (*p == '|') { + if (q > r) { + *q = 0; + return r; + } else { + Pipe(); + ++p; + } + } else { + *q++ = *p; + } + break; + + case STATE_STR: + if (!*p) { + Write("cmd: error: unterminated single string\n", 0); + exit(6); + } + if (*p == '\'') { + t = STATE_SHELL; + } else { + *q++ = *p; + } + break; + + case STATE_QUO: + if (!*p) { + Write("cmd: error: unterminated quoted string\n", 0); + exit(6); + } + if (*p == '"') { + t = STATE_SHELL; + } 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; + + default: + unreachable; + } + } +} + +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; + unsupported['}'] = true; + unsupported[';'] = true; + unsupported['?'] = true; + unsupported['!'] = true; + + if (argc != 3) { + Write(prog, ": error: wrong number of args\n", 0); + exit(10); + } + + if (strcmp(argv[1], "-c")) { + Write(prog, ": error: argv[1] should -c\n", 0); + exit(11); + } + + p = cmd = argv[2]; + if (strlen(cmd) >= ARG_MAX) { + Write(prog, ": error: cmd too long: ", cmd, "\n", 0); + exit(12); + } + + 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(arg + 3, arg[0] - '0', O_WRONLY | O_CREAT | O_APPEND); + } else if (arg[0] == '>' && arg[1] == '>') { + Open(arg + 2, 1, O_WRONLY | O_CREAT | O_APPEND); + } else if (isdigit(arg[0]) && arg[1] == '>') { + Open(arg + 2, arg[0] - '0', O_WRONLY | O_CREAT | O_TRUNC); + } else if (arg[0] == '>') { + Open(arg + 1, 1, O_WRONLY | O_CREAT | O_TRUNC); + } else if (arg[0] == '<') { + Open(arg + 1, 0, O_RDONLY); + } else { + args[n++] = arg; + args[n] = 0; + } + } else { + Write(prog, ": error: too many args\n", 0); + exit(13); + } + } + + Exec(); +} diff --git a/libc/stdio/cocmd.internal.h b/libc/stdio/cocmd.internal.h new file mode 100644 index 000000000..c1cc3f9d3 --- /dev/null +++ b/libc/stdio/cocmd.internal.h @@ -0,0 +1,10 @@ +#ifndef COSMOPOLITAN_LIBC_STDIO_COCMD_INTERNAL_H_ +#define COSMOPOLITAN_LIBC_STDIO_COCMD_INTERNAL_H_ +#if !(__ASSEMBLER__ + __LINKER__ + 0) +COSMOPOLITAN_C_START_ + +int cocmd(int, char **); + +COSMOPOLITAN_C_END_ +#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */ +#endif /* COSMOPOLITAN_LIBC_STDIO_COCMD_INTERNAL_H_ */ diff --git a/libc/stdio/popen.c b/libc/stdio/popen.c index 216a74c43..252332b2e 100644 --- a/libc/stdio/popen.c +++ b/libc/stdio/popen.c @@ -29,6 +29,16 @@ /** * Spawns subprocess and returns pipe stream. + * + * This embeds the cocmd.com shell interpreter which supports a limited + * subset of the bourne shell that's significantly faster: + * + * - pipelines + * - single quotes + * - double quotes + * - input redirection, e.g. `path`, `>>append`, `2>err.txt, `2>&1` + * * @see pclose() */ FILE *popen(const char *cmdline, const char *mode) { diff --git a/libc/stdio/system.c b/libc/stdio/system.c index d7206fecb..98699c225 100644 --- a/libc/stdio/system.c +++ b/libc/stdio/system.c @@ -32,10 +32,14 @@ /** * Launches program with system command interpreter. * - * Warning: Caution is very much advised on Windows where this function - * currently delegates to CMD.EXE, which has notoriously mysterious and - * insecure escaping rules. Much better idea is to not use this at all, - * favoring instead explicit execve() invocations without using shells. + * This embeds the cocmd.com shell interpreter which supports a limited + * subset of the bourne shell that's significantly faster: + * + * - pipelines + * - single quotes + * - double quotes + * - input redirection, e.g. `path`, `>>append`, `2>err.txt, `2>&1` * * @param cmdline is an interpreted Turing-complete command * @return -1 if child process couldn't be created, otherwise a wait @@ -45,11 +49,7 @@ int system(const char *cmdline) { int pid, wstatus; sigset_t chldmask, savemask; struct sigaction ignore, saveint, savequit; - if (!cmdline) { - if (IsWindows()) return 1; - if (!access(_PATH_BSHELL, X_OK)) return 1; - return 0; - } + if (!cmdline) return 1; ignore.sa_flags = 0; ignore.sa_handler = SIG_IGN; sigemptyset(&ignore.sa_mask); diff --git a/libc/stdio/systemexec.c b/libc/stdio/systemexec.c index 14f086003..eb5d9baa0 100644 --- a/libc/stdio/systemexec.c +++ b/libc/stdio/systemexec.c @@ -16,33 +16,11 @@ │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │ │ PERFORMANCE OF THIS SOFTWARE. │ ╚─────────────────────────────────────────────────────────────────────────────*/ -#include "libc/calls/calls.h" -#include "libc/dce.h" -#include "libc/macros.internal.h" -#include "libc/paths.h" #include "libc/runtime/runtime.h" -#include "libc/str/str.h" -#include "libc/sysv/errfuns.h" +#include "libc/stdio/cocmd.internal.h" +#include "libc/stdio/stdio.h" // Support code for system() and popen(). -// TODO(jart): embed cocmd instead of using /bin/sh and cmd.exe int systemexec(const char *cmdline) { - size_t n, m; - char *a, *b, *argv[4], comspec[PATH_MAX]; - if (!IsWindows()) { - argv[0] = _PATH_BSHELL; - argv[1] = "-c"; - } else { - b = "cmd.exe"; - a = kNtSystemDirectory; - if ((n = strlen(a)) + (m = strlen(b)) >= ARRAYLEN(comspec)) { - return enametoolong(); - } - memcpy(mempcpy(comspec, a, n), b, m + 1); - argv[0] = comspec; - argv[1] = "/C"; - } - argv[2] = cmdline; - argv[3] = NULL; - return execv(argv[0], argv); + _Exit(cocmd(3, (char *[]){"cocmd.com", "-c", cmdline, 0})); } diff --git a/test/libc/stdio/system_test.c b/test/libc/stdio/system_test.c index 57750b19f..6e67abcd4 100644 --- a/test/libc/stdio/system_test.c +++ b/test/libc/stdio/system_test.c @@ -23,6 +23,7 @@ #include "libc/runtime/runtime.h" #include "libc/stdio/stdio.h" #include "libc/sysv/consts/o.h" +#include "libc/testlib/ezbench.h" #include "libc/testlib/testlib.h" #include "libc/x/x.h" @@ -31,11 +32,8 @@ char testlib_enable_tmp_setup_teardown; TEST(system, testStdoutRedirect) { int ws; testlib_extract("/zip/echo.com", "echo.com", 0755); - testlib_extract("/zip/cocmd.com", "cocmd.com", 0755); - setenv("PATH", ".", true); // avoid / vs. \ until cocmd.com is ready - _PATH_BSHELL = "cocmd.com"; // cmd.exe shall still be used on windows ASSERT_TRUE(system(0)); - ws = system("echo.com hello >hello.txt"); + ws = system("./echo.com hello >hello.txt"); ASSERT_TRUE(WIFEXITED(ws)); ASSERT_EQ(0, WEXITSTATUS(ws)); EXPECT_STREQ("hello\n", _gc(xslurp("hello.txt", 0))); @@ -44,12 +42,14 @@ TEST(system, testStdoutRedirect) { TEST(system, testStdoutRedirect_withSpacesInFilename) { int ws; testlib_extract("/zip/echo.com", "echo.com", 0755); - testlib_extract("/zip/cocmd.com", "cocmd.com", 0755); - setenv("PATH", ".", true); // avoid / vs. \ until cocmd.com is ready - _PATH_BSHELL = "cocmd.com"; // cmd.exe shall still be used on windows ASSERT_TRUE(system(0)); - ws = system("echo.com hello >\"hello there.txt\""); + ws = system("./echo.com hello >\"hello there.txt\""); ASSERT_TRUE(WIFEXITED(ws)); ASSERT_EQ(0, WEXITSTATUS(ws)); EXPECT_STREQ("hello\n", _gc(xslurp("hello there.txt", 0))); } + +BENCH(system, bench) { + testlib_extract("/zip/echo.com", "echo.com", 0755); + EZBENCH2("system", donothing, system("./echo.com hi >/dev/null")); +} diff --git a/tool/build/cocmd.c b/tool/build/cocmd.c index 869bd6960..ec3d89a97 100644 --- a/tool/build/cocmd.c +++ b/tool/build/cocmd.c @@ -16,255 +16,8 @@ │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │ │ PERFORMANCE OF THIS SOFTWARE. │ ╚─────────────────────────────────────────────────────────────────────────────*/ -#include "libc/calls/calls.h" -#include "libc/errno.h" -#include "libc/fmt/itoa.h" -#include "libc/macros.internal.h" -#include "libc/mem/mem.h" -#include "libc/runtime/runtime.h" -#include "libc/stdio/stdio.h" -#include "libc/str/str.h" -#include "libc/sysv/consts/o.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_SHELL 0 -#define STATE_STR 1 -#define STATE_QUO 2 - -char *p; -char *q; -size_t n; -char *cmd; -char *args[8192]; -const char *prog; -char argbuf[ARG_MAX]; -bool unsupported[256]; - -void Write(const char *s, ...) { - va_list va; - va_start(va, s); - do { - write(2, s, strlen(s)); - } while ((s = va_arg(va, const char *))); - va_end(va); -} - -wontreturn void UnsupportedSyntax(unsigned char c) { - char cbuf[2]; - char ibuf[13]; - cbuf[0] = c; - cbuf[1] = 0; - FormatOctal32(ibuf, c, true); - Write(prog, ": unsupported shell syntax '", cbuf, "' (", ibuf, "): ", cmd, - "\n", 0); - exit(4); -} - -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"; - Write(thing, ": ", call, "() failed: ", estr, " (", ibuf, ")\n", 0); - exit(rc); -} - -void Open(const char *path, int fd, int flags) { - const char *err; - close(fd); - if (open(path, flags, 0644) == -1) { - SysExit(7, "open", path); - } -} - -wontreturn void Exec(void) { - const char *s; - if (!n) { - Write(prog, ": error: too few args\n", 0); - exit(5); - } - execv(args[0], args); - SysExit(127, "execve", args[0]); -} - -void Pipe(void) { - int pid, pfds[2]; - if (pipe2(pfds, O_CLOEXEC)) { - SysExit(8, "pipe2", prog); - } - if ((pid = vfork()) == -1) { - SysExit(9, "vfork", prog); - } - if (!pid) { - dup2(pfds[1], 1); - Exec(); - } - dup2(pfds[0], 0); - n = 0; -} - -char *Tokenize(void) { - char *r; - int c, t; - while (*p == ' ' || *p == '\t' || *p == '\n' || - (p[0] == '\\' && p[1] == '\n')) { - ++p; - } - if (!*p) return 0; - t = STATE_SHELL; - for (r = q;; ++p) { - switch (t) { - - case STATE_SHELL: - if (unsupported[*p & 255]) { - UnsupportedSyntax(*p); - } - if (!*p || *p == ' ' || *p == '\t') { - *q++ = 0; - return r; - } else if (*p == '"') { - t = STATE_QUO; - } else if (*p == '\'') { - t = STATE_STR; - } else if (*p == '\\') { - if (!p[1]) UnsupportedSyntax(*p); - *q++ = *++p; - } else if (*p == '|') { - if (q > r) { - *q = 0; - return r; - } else { - Pipe(); - ++p; - } - } else { - *q++ = *p; - } - break; - - case STATE_STR: - if (!*p) { - Write("cmd: error: unterminated single string\n", 0); - exit(6); - } - if (*p == '\'') { - t = STATE_SHELL; - } else { - *q++ = *p; - } - break; - - case STATE_QUO: - if (!*p) { - Write("cmd: error: unterminated quoted string\n", 0); - exit(6); - } - if (*p == '"') { - t = STATE_SHELL; - } 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; - - default: - unreachable; - } - } -} +#include "libc/stdio/cocmd.internal.h" int main(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; - unsupported['}'] = true; - unsupported[';'] = true; - unsupported['?'] = true; - unsupported['!'] = true; - - if (argc != 3) { - Write(prog, ": error: wrong number of args\n", 0); - exit(10); - } - - if (strcmp(argv[1], "-c")) { - Write(prog, ": error: argv[1] should -c\n", 0); - exit(11); - } - - p = cmd = argv[2]; - if (strlen(cmd) >= ARG_MAX) { - Write(prog, ": error: cmd too long: ", cmd, "\n", 0); - exit(12); - } - - 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(arg + 3, arg[0] - '0', O_WRONLY | O_CREAT | O_APPEND); - } else if (arg[0] == '>' && arg[1] == '>') { - Open(arg + 2, 1, O_WRONLY | O_CREAT | O_APPEND); - } else if (isdigit(arg[0]) && arg[1] == '>') { - Open(arg + 2, arg[0] - '0', O_WRONLY | O_CREAT | O_TRUNC); - } else if (arg[0] == '>') { - Open(arg + 1, 1, O_WRONLY | O_CREAT | O_TRUNC); - } else if (arg[0] == '<') { - Open(arg + 1, 0, O_RDONLY); - } else { - args[n++] = arg; - args[n] = 0; - } - } else { - Write(prog, ": error: too many args\n", 0); - exit(13); - } - } - - Exec(); + return cocmd(argc, argv); }