From 33ca12a4653752d179e6296c7ca2f91a626d30f3 Mon Sep 17 00:00:00 2001 From: Mole Shang <135e2@135e2.dev> Date: Wed, 17 Jan 2024 11:33:39 +0800 Subject: lab util: finish --- user/xargs.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 user/xargs.c (limited to 'user/xargs.c') diff --git a/user/xargs.c b/user/xargs.c new file mode 100644 index 0000000..b5b9bee --- /dev/null +++ b/user/xargs.c @@ -0,0 +1,60 @@ +#include "kernel/types.h" + +#include "kernel/param.h" +#include "kernel/stat.h" +#include "user/user.h" + +#define is_blank(chr) (chr == ' ' || chr == '\t') + +int +main(int argc, char* argv[]) +{ + char buf[2048], ch; + char* p = buf; + char* v[MAXARG]; + int c; + int blanks = 0; + int offset = 0; + + if (argc <= 1) { + fprintf(2, "usage: xargs [argv...]\n"); + exit(1); + } + + for (c = 1; c < argc; c++) { + v[c - 1] = argv[c]; + } + --c; + + while (read(0, &ch, 1) > 0) { + if (is_blank(ch)) { + blanks++; + continue; + } + + if (blanks) { + buf[offset++] = 0; + + v[c++] = p; + p = buf + offset; + + blanks = 0; + } + + if (ch != '\n') { + buf[offset++] = ch; + } else { + v[c++] = p; + p = buf + offset; + + if (!fork()) { + exit(exec(v[0], v)); + } + wait(0); + + c = argc - 1; + } + } + + exit(0); +} -- cgit v1.2.3