os

An operating system
git clone https://erai.gay/code/os/
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cpio.om (2966B)


      1 func main(argc: int, argv: **byte, envp: **byte) {
      2 	var opts: int;
      3 	var i: int;
      4 	var a: alloc;
      5 	var fd: int;
      6 	var name: *byte;
      7 	var stdin: *file;
      8 	var stdout: *file;
      9 	var stderr: *file;
     10 	var stat: stat;
     11 	var buf: *byte;
     12 	var len: int;
     13 	var n: int;
     14 	var m: int;
     15 	var k: int;
     16 	var ret: int;
     17 
     18 	setup_alloc(&a);
     19 
     20 	i = 1;
     21 	loop {
     22 		if i >= argc {
     23 			break;
     24 		}
     25 
     26 		if !strcmp(argv[i], "-o") {
     27 			opts = opts | 1;
     28 		} else {
     29 			die("invalid argument");
     30 		}
     31 
     32 		i = i + 1;
     33 	}
     34 
     35 	stdin = fopen(0, &a);
     36 	stdout = fopen(1, &a);
     37 	stderr = fopen(2, &a);
     38 
     39 	name = alloc(&a, 4096);
     40 	buf = alloc(&a, 4096);
     41 
     42 	loop {
     43 		if stdin.eof {
     44 			break;
     45 		}
     46 
     47 		len = fgets(stdin, name, 4096);
     48 		if len == 0 {
     49 			continue;
     50 		}
     51 
     52 		if len == 4096 {
     53 			fflush(stdout);
     54 			fputs(stderr, "name truncated: ");
     55 			fputs(stderr, name);
     56 			fputs(stderr, "\n");
     57 			exit(1);
     58 		}
     59 
     60 		fd = open(name, 0, 0);
     61 		if fd < 0 {
     62 			fflush(stdout);
     63 			fputs(stderr, "failed to open: ");
     64 			fputs(stderr, name);
     65 			fputs(stderr, "\n");
     66 			exit(1);
     67 		}
     68 
     69 		if fstat(fd, &stat) < 0 {
     70 			fflush(stdout);
     71 			fputs(stderr, "stat failed: ");
     72 			fputs(stderr, name);
     73 			fputs(stderr, "\n");
     74 			exit(1);
     75 		}
     76 
     77 		// header
     78 		fputs(stdout, "070701");
     79 		fputh32(stdout, stat.ino & (-1 >> 32));
     80 		fputh32(stdout, stat.mode);
     81 		fputh32(stdout, 0);
     82 		fputh32(stdout, 0);
     83 		fputh32(stdout, stat.nlink);
     84 		fputh32(stdout, stat.mtime);
     85 		fputh32(stdout, stat.size);
     86 		fputh32(stdout, stat.dev >> 8);
     87 		fputh32(stdout, stat.dev & 255);
     88 		fputh32(stdout, stat.rdev >> 8);
     89 		fputh32(stdout, (stat.rdev) & 255);
     90 		fputh32(stdout, len + 1);
     91 		fputh32(stdout, 0);
     92 
     93 		fputs(stdout, name);
     94 		fputc(stdout, 0);
     95 
     96 		// align to four bytes
     97 		falign(stdout, len + 3);
     98 		fflush(stdout);
     99 
    100 		// copy data
    101 		n = 0;
    102 		loop {
    103 			if n == stat.size {
    104 				break;
    105 			}
    106 
    107 			k = read(fd, buf, 4096);
    108 			if k <= 0 {
    109 				die("failed to read");
    110 			}
    111 
    112 			if n + k > stat.size {
    113 				k = stat.size - n;
    114 			}
    115 
    116 			m = 0;
    117 			loop {
    118 				if m == k {
    119 					break;
    120 				}
    121 
    122 				ret = write(1, &buf[m], k - m);
    123 				if ret < 0 {
    124 					die("failed to write");
    125 				}
    126 
    127 				m = m + ret;
    128 			}
    129 
    130 			n = n + k;
    131 		}
    132 
    133 		// align to four bytes
    134 		falign(stdout, stat.size);
    135 		fflush(stdout);
    136 
    137 		close(fd);
    138 	}
    139 
    140 	// trailer
    141 	fputs(stdout, "070701");
    142 	fputh32(stdout, 0);
    143 	fputh32(stdout, 0);
    144 	fputh32(stdout, 0);
    145 	fputh32(stdout, 0);
    146 	fputh32(stdout, 0);
    147 	fputh32(stdout, 0);
    148 	fputh32(stdout, 0);
    149 	fputh32(stdout, 0);
    150 	fputh32(stdout, 0);
    151 	fputh32(stdout, 0);
    152 	fputh32(stdout, 0);
    153 	fputh32(stdout, 11);
    154 	fputh32(stdout, 0);
    155 	fputs(stdout, "TRAILER!!!");
    156 	fputc(stdout, 0);
    157 	falign(stdout, 13);
    158 
    159 	fflush(stdout);
    160 }
    161 
    162 func fputh32(f: *file, x: int) {
    163 	var i: int;
    164 
    165 	if x > (-1 >> 32) {
    166 		fflush(f);
    167 		die("cpio: too large");
    168 	}
    169 
    170 	i = 32;
    171 	loop {
    172 		if i == 0 {
    173 			break;
    174 		}
    175 
    176 		i = i - 4;
    177 
    178 		fputc(f, "0123456789abcdef"[(x >> i) & 15] as int);
    179 	}
    180 }
    181 
    182 func falign(f: *file, n: int) {
    183 	var len: int;
    184 	len = (4 - (n & 3)) & 3;
    185 	loop {
    186 		if len == 0 {
    187 			break;
    188 		}
    189 
    190 		fputc(f, 0);
    191 
    192 		len = len - 1;
    193 	}
    194 }