Add pipes to `shell`, add `wc`

build.sh

@@ -24,3 +24,4 @@ mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/cat ::bin/cat
 mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/cp ::bin/cp
 mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/mkdir ::bin/mkdir
 mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/rm ::bin/rm
+mcopy -i build/os.img@@"$((partition_offset * sector_size))" build/wc ::bin/wc

meson.build

@@ -427,3 +427,42 @@ custom_target(
   command: ['objcopy', '-O', 'binary', '@INPUT@', '@OUTPUT@'],
   build_by_default: true,
 )
+
+wc_start = custom_target(
+  'wc_start',
+  input:  'src/user/start.asm',
+  output: 'wc_start.o',
+  command: [nasm, '-f', 'elf64', '-o', '@OUTPUT@', '@INPUT@'],
+)
+
+wc_syscall = custom_target(
+  'wc_syscall',
+  input:  'src/user/syscall.asm',
+  output: 'wc_syscall.o',
+  command: [nasm, '-f', 'elf64', '-o', '@OUTPUT@', '@INPUT@'],
+)
+
+wc_elf = executable(
+  'wc.elf',
+  sources: [wc_start, wc_syscall, lib_sources, 'src/user/app/wc/wc.c'],
+  c_args: [
+    '-ffreestanding',
+    '-nostdlib',
+    '-fno-stack-protector',
+    '-mcmodel=large',
+    '-DVERSION="' + meson.project_version() + '"',
+  ],
+  link_args: [
+    '-T', meson.project_source_root() / 'src/user/linker.ld',
+    '-nostdlib',
+  ],
+  link_depends: 'src/user/linker.ld',
+)
+
+custom_target(
+  'wc',
+  input:  wc_elf,
+  output: 'wc',
+  command: ['objcopy', '-O', 'binary', '@INPUT@', '@OUTPUT@'],
+  build_by_default: true,
+)

src/kernel/kernel.c

@@ -79,10 +79,10 @@ void kernel_main() {
   fs_read(shell_node, 0, shell_node->size, shell_code);
   fs_close(shell_node);
 
-  process_t *terminal = process_create(kernel, terminal_code, terminal_node->size);
+  process_t *terminal = process_create(kernel, terminal_code, terminal_node->size, 0, 1);
   memory_free(terminal_code);
 
-  process_t *shell = process_create(kernel, shell_code, shell_node->size);
+  process_t *shell = process_create(kernel, shell_code, shell_node->size, 0, 1);
   memory_free(shell_code);
 
   uint64_t *terminal_stack = (uint64_t *)terminal->user_stack;

src/kernel/path.c

@@ -31,6 +31,9 @@ path_t *path_open(const path_t *base, const char *path, uint64_t flags) {
     }
 
     if (string_empty(path_components[i]) || string_equal(path_components[i], ".")) {
+      if (i == path_length - 1 && result->depth) {
+        // TODO Apply flags to current top of stack.
+      }
       continue;
     } else if (string_equal(path_components[i], "..")) {
       if (result->depth > 1) {

src/kernel/process.c

@@ -14,7 +14,7 @@ static uint64_t free_pid = 1;
 
 process_t *current_process;
 
-process_t *process_create(const process_t *parent, const uint8_t *code, uint64_t size) {
+process_t *process_create(const process_t *parent, const uint8_t *code, uint64_t size, uint64_t stdin, uint64_t stdout) {
   if (size >= USER_VIRTUAL_HEAP - USER_VIRTUAL_CODE) {
     return NUL;
   }
@@ -29,6 +29,10 @@ process_t *process_create(const process_t *parent, const uint8_t *code, uint64_t
     return NUL;
   }
 
+  if (stdin >= MAX_FDS || !parent->fds[stdin] || stdout > MAX_FDS || !parent->fds[stdout]) {
+    return NUL;
+  }
+
   process_t *proc = processes[free_pi] = memory_allocate(sizeof(process_t));
 
   proc->parent = parent;
@@ -71,8 +75,8 @@ process_t *process_create(const process_t *parent, const uint8_t *code, uint64_t
   proc->pid = free_pid++;
   proc->state = PROCESS_RUNNING;
   proc->cwd = path_open_again(parent->cwd);
-  proc->fds[0] = parent->fds[0];
-  proc->fds[1] = parent->fds[1];
+  proc->fds[0] = parent->fds[stdin];
+  proc->fds[1] = parent->fds[stdout];
   proc->free_fd = 2;
   proc->code = EXIT_CODE_OK;
 

src/kernel/process.h

@@ -36,7 +36,7 @@ extern process_t *current_process;
 
 extern void process_trampoline();
 
-process_t *process_create(const process_t *parent, const uint8_t *code, uint64_t size);
+process_t *process_create(const process_t *parent, const uint8_t *code, uint64_t size, uint64_t stdin, uint64_t stdout);
 
 process_t *process_get(uint64_t pid);
 

src/kernel/syscall.asm

@@ -28,6 +28,7 @@ syscall_entry:
     push r14
     push r15
 
+    mov r9, r8      ; arg5
     mov r8, r10     ; arg4
     mov rcx, rdx    ; arg3
     mov rdx, rsi    ; arg2

src/kernel/syscall.c

@@ -2,6 +2,7 @@
 #include "src/kernel/fs.h"
 #include "src/kernel/gdt.h"
 #include "src/kernel/path.h"
+#include "src/kernel/pipe.h"
 #include "src/kernel/process.h"
 #include "src/kernel/stream.h"
 #include "src/lib/layout.h"
@@ -89,7 +90,7 @@ static uint64_t chdir(const char *path) {
   return current_process->cwd->depth;
 }
 
-static uint64_t spawn(const char *path, uint64_t argc, const char **argv) {
+static uint64_t spawn(const char *path, uint64_t argc, const char **argv, uint64_t stdin, uint64_t stdout) {
   fs_node_t *node = path_open_node(current_process->cwd, path, OPEN_FILE);
   if (!node) {
     return EXIT_CODE_NOT_FOUND;
@@ -109,7 +110,7 @@ static uint64_t spawn(const char *path, uint64_t argc, const char **argv) {
     memory_copy(argv[i], sizes[i], blob + offsets[i]);
   }
 
-  process_t *child = process_create(current_process, bin, node->size);
+  process_t *child = process_create(current_process, bin, node->size, stdin, stdout);
 
   memory_free(bin);
   fs_close(node);
@@ -192,6 +193,16 @@ static uint64_t remove(const char *path) {
   return 0;
 }
 
+static uint64_t pipe(uint64_t *write_fd, uint64_t *read_fd) {
+  if (current_process->free_fd + 2 >= MAX_FDS) {
+    return (uint64_t)-1;
+  }
+  *write_fd = current_process->free_fd++;
+  *read_fd = current_process->free_fd++;
+  pipe_init(&current_process->fds[*write_fd], &current_process->fds[*read_fd]);
+  return 0;
+}
+
 static void exit(exit_code_t code) {
   current_process->state = PROCESS_ZOMBIE;
   current_process->code = code;
@@ -206,7 +217,7 @@ static void exit(exit_code_t code) {
   process_next();
 }
 
-uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t arg3, __attribute__((unused)) uint64_t arg4) {
+uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5) {
   switch (func) {
   case SYSCALL_READ:
     return read(arg1, arg2, (char *)arg3);
@@ -217,7 +228,7 @@ uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t
   case SYSCALL_CHDIR:
     return chdir((const char *)arg1);
   case SYSCALL_SPAWN:
-    return spawn((const char *)arg1, arg2, (const char **)arg3);
+    return spawn((const char *)arg1, arg2, (const char **)arg3, arg4, arg5);
   case SYSCALL_WAIT:
     return wait(arg1);
   case SYSCALL_OPEN:
@@ -228,6 +239,8 @@ uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t
     return truncate(arg1, arg2);
   case SYSCALL_REMOVE:
     return remove((char *)arg1);
+  case SYSCALL_PIPE:
+    return pipe((uint64_t *)arg1, (uint64_t *)arg2);
   case SYSCALL_EXIT:
     exit(arg1);
     return 0;

src/kernel/syscall.h

@@ -4,4 +4,4 @@
 
 void syscall_init();
 
-uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t arg3, uint64_t arg4);
+uint64_t syscall_dispatch(uint64_t func, uint64_t arg1, uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5);

src/lib/string.c

@@ -33,6 +33,30 @@ uint8_t string_equal(const char *l, const char *r) {
   return *l == *r;
 }
 
+uint64_t string_trim(char *string, char character, char **result) {
+  while (*string == character) {
+    string++;
+  }
+  *result = string;
+
+  if (*string == '\0') {
+    return 0;
+  }
+
+  char *end = string;
+  while (*end != '\0') {
+    end++;
+  }
+
+  end--;
+  while (string < end && *end == character) {
+    *end = '\0';
+    end--;
+  }
+
+  return (uint64_t)(end - string + 1);
+}
+
 uint64_t string_split(char *string, char separator, uint64_t max, char **result) {
   uint64_t count = 1;
   *result = string;

src/lib/string.h

@@ -10,6 +10,8 @@ uint64_t string_length(const char *s);
 
 uint8_t string_equal(const char *l, const char *r);
 
+uint64_t string_trim(char *string, char character, char **result);
+
 uint64_t string_split(char *string, char separator, uint64_t max, char **result);
 
 uint64_t string_byte_to_hex(uint8_t value, uint64_t max, char *result);

src/lib/syscall.h

@@ -8,6 +8,7 @@
 #define SYSCALL_CLOSE 7
 #define SYSCALL_TRUNCATE 8
 #define SYSCALL_REMOVE 9
+#define SYSCALL_PIPE 10
 #define SYSCALL_EXIT 60
 
 #define OPEN_CREATE 0b0001

src/user/app/cat/cat.c

@@ -7,33 +7,38 @@
 #define PRINT_S(s) write(1, s, sizeof(s) - 1);
 #define PRINT_D(s) write(1, s, string_length(s));
 
-exit_code_t cat(const char *path) {
-  uint64_t fd = open(path, OPEN_FILE);
-
-  if (fd == (uint64_t)-1) {
-    PRINT_S("cat: path does not exist\n");
-    return EXIT_CODE_GENERAL_FAILURE;
-  }
-
+exit_code_t pass(uint64_t fd) {
   static char buffer[BLOCK_SIZE];
   uint64_t bytes;
   while ((bytes = read(fd, BLOCK_SIZE, buffer))) {
     if (bytes == (uint64_t)-1) {
       PRINT_S("cat: could not read file\n");
-      close(fd);
       return EXIT_CODE_GENERAL_FAILURE;
     }
     write(1, buffer, bytes);
   }
 
+  return EXIT_CODE_OK;
+}
+
+exit_code_t cat(const char *path) {
+  uint64_t fd = open(path, OPEN_FILE);
+
+  if (fd == (uint64_t)-1) {
+    PRINT_S("cat: path does not exist\n");
+    return EXIT_CODE_GENERAL_FAILURE;
+  }
+
+  exit_code_t code = pass(fd);
+
   close(fd);
 
-  return 0;
+  return code;
 }
 
 exit_code_t main(uint64_t argc, const char **argv) {
   if (argc == 1) {
-    return cat(".");
+    return pass(0);
   }
 
   uint64_t code = EXIT_CODE_OK;

src/user/app/shell/shell.c

@@ -3,15 +3,15 @@
 #include "src/lib/util.h"
 #include "src/user/syscall.h"
 
-static void help(uint8_t argc, char **argv);
-static void cd(uint8_t argc, char **argv);
+static void help(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
+static void cd(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
 
 #define PATH "/bin/"
 
-#define PRINT_S(s) write(1, s, sizeof(s) - 1);
-#define PRINT_D(s) write(1, s, string_length(s));
+#define PRINT_S(o, s) write(o, s, sizeof(s) - 1);
+#define PRINT_D(o, s) write(o, s, string_length(s));
 
-typedef void (*app_t)(uint8_t argc, char **argv);
+typedef void (*app_t)(uint8_t argc, char **argv, uint64_t stdin, uint64_t stdout);
 
 typedef struct {
   const char *name;
@@ -23,27 +23,27 @@ static app_entry_t builtins[] = {
     {"cd", cd},
 };
 
-static void help(uint8_t argc, __attribute__((unused)) char **argv) {
+static void help(uint8_t argc, __attribute__((unused)) char **argv, __attribute__((unused)) uint64_t stdin, uint64_t stdout) {
   if (argc > 1) {
-    PRINT_S("help: expects no arguments");
+    PRINT_S(stdout, "help: expects no arguments\n");
     return;
   }
 
-  PRINT_S("Available commands:\n");
+  PRINT_S(stdout, "Available commands:\n");
   for (uint64_t i = 0; i < sizeof(builtins) / sizeof(app_entry_t); i++) {
-    PRINT_D(builtins[i].name);
-    PRINT_S("\n");
+    PRINT_D(stdout, builtins[i].name);
+    PRINT_S(stdout, "\n");
   }
 }
 
-static void cd(uint8_t argc, char **argv) {
+static void cd(uint8_t argc, char **argv, __attribute__((unused)) uint64_t stdin, uint64_t stdout) {
   if (argc != 2) {
-    PRINT_S("cd: requires a single path\n");
+    PRINT_S(stdout, "cd: requires a single path\n");
     return;
   }
 
   if (chdir(argv[1]) == (uint64_t)-1) {
-    PRINT_S("cd: path does not exist\n");
+    PRINT_S(stdout, "cd: path does not exist\n");
   }
 }
 
@@ -53,16 +53,23 @@ static void print_prompt() {
   char *components[16];
   uint8_t cl = string_split(path, '/', 16, components);
 
-  PRINT_S("[")
-  PRINT_D(pl == 1 ? "/" : components[cl - 1]);
-  PRINT_S("]$ ");
+  PRINT_S(1, "[")
+  PRINT_D(1, pl == 1 ? "/" : components[cl - 1]);
+  PRINT_S(1, "]$ ");
 }
 
-static void execute(char *command) {
-  char *argv[16];
-  uint8_t argc = (uint8_t)string_split(command, ' ', 16, argv);
+static void free_fds(uint64_t *fds, uint8_t fds_count) {
+  for (uint8_t i = 0; i < fds_count; i++) {
+    close(fds[i]);
+  }
+}
 
-  PRINT_S("\n");
+static void kill_pids(__attribute__((unused)) uint64_t *pids, __attribute__((unused)) uint8_t pid_count) {
+  // TODO.
+}
+
+static void execute(char *command) {
+  PRINT_S(1, "\n");
 
   if (string_equal(command, "^C")) {
     print_prompt();
@@ -71,34 +78,85 @@ static void execute(char *command) {
 
   if (string_equal(command, "^D")) {
     exit(EXIT_CODE_OK);
+    return;
+  }
+
+  char *subcommands[16];
+  uint8_t subcommands_count = (uint8_t)string_split(command, '|', 16, subcommands);
+
+  uint64_t fds[32];
+  uint8_t fds_count = 0;
+
+  uint64_t pids[16];
+  uint8_t pids_count = 0;
+
+  for (uint8_t i = 0; i < subcommands_count; i++) {
+    string_trim(subcommands[i], ' ', &subcommands[i]);
+
+    char *argv[16];
+    uint8_t argc = (uint8_t)string_split(subcommands[i], ' ', 16, argv);
+
+    uint64_t stdin = 0;
+    uint64_t stdout = 1;
+
+    if (i > 0) {
+      stdin = fds[fds_count - 1];
+    }
+    if (i < subcommands_count - 1) {
+      if (pipe(&fds[fds_count], &fds[fds_count + 1]) == (uint64_t)-1) {
+        kill_pids(pids, pids_count);
+        free_fds(fds, fds_count);
+        print_prompt();
+        return;
+      }
+      fds_count += 2;
+      stdout = fds[fds_count - 2];
     }
 
-  uint8_t i;
-  for (i = 0; i < sizeof(builtins) / sizeof(app_entry_t); i++) {
-    if (string_equal(argv[0], builtins[i].name)) {
-      builtins[i].app(argc, argv);
+    uint8_t j;
+    for (j = 0; j < sizeof(builtins) / sizeof(app_entry_t); j++) {
+      if (string_equal(argv[0], builtins[j].name)) {
+        builtins[j].app(argc, argv, stdin, stdout);
+        pids[pids_count++] = 0;
         break;
       }
     }
-  if (i == sizeof(builtins) / sizeof(app_entry_t)) {
+    if (j == sizeof(builtins) / sizeof(app_entry_t)) {
       uint64_t size = sizeof(PATH) + string_length(argv[0]) + 1;
       char *path = memory_allocate(size);
       memory_copy(PATH, sizeof(PATH), path);
       memory_copy(argv[0], size - sizeof(PATH), path + sizeof(PATH) - 1);
-    uint64_t pid = spawn(path, argc, (const char **)argv);
+      uint64_t pid = spawn(path, argc, (const char **)argv, stdin, stdout);
       memory_free(path);
 
-    if (pid == EXIT_CODE_NOT_FOUND) {
-      PRINT_S("shell: program not found\n");
+      if (pid == (uint64_t)-1) {
+        kill_pids(pids, pids_count);
+        free_fds(fds, fds_count);
+        print_prompt();
+        return;
       } else {
-      waitpid(pid);
+        pids[pids_count++] = pid;
       }
     }
+  }
+
+  for (uint8_t i = 0; i < pids_count; i++) {
+    if (pids[i]) {
+      waitpid(pids[i]);
+    }
+    if (i > 0) {
+      close(fds[(i - 1) * 2 + 1]);
+    }
+    if (i < pids_count - 1) {
+      close(fds[i * 2]);
+    }
+  }
+
   print_prompt();
 }
 
 uint64_t main() {
-  PRINT_D("Welcome to FreywarOS v" VERSION "!\n\n");
+  PRINT_D(1, "Welcome to FreywarOS v" VERSION "!\n\n");
 
   print_prompt();
 

src/user/app/wc/wc.c

@@ -0,0 +1,59 @@
+#include "src/lib/string.h"
+#include "src/lib/syscall.h"
+#include "src/lib/util.h"
+#include "src/user/syscall.h"
+
+#define BLOCK_SIZE 65536
+
+#define PRINT_S(s) write(1, s, sizeof(s) - 1);
+#define PRINT_D(s) write(1, s, string_length(s));
+
+exit_code_t pass(uint64_t fd) {
+  static char buffer[BLOCK_SIZE];
+  uint64_t bytes;
+  uint64_t total = 0;
+  while ((bytes = read(fd, BLOCK_SIZE, buffer))) {
+    if (bytes == (uint64_t)-1) {
+      PRINT_S("wc: could not read file\n");
+      return EXIT_CODE_GENERAL_FAILURE;
+    } else {
+      total += bytes;
+    }
+  }
+
+  uint64_t l = string_format("%d\n", BLOCK_SIZE, buffer, total);
+  write(1, buffer, l);
+
+  return EXIT_CODE_OK;
+}
+
+exit_code_t wc(const char *path) {
+  uint64_t fd = open(path, OPEN_FILE);
+
+  if (fd == (uint64_t)-1) {
+    PRINT_S("wc: path does not exist\n");
+    return EXIT_CODE_GENERAL_FAILURE;
+  }
+
+  exit_code_t code = pass(fd);
+
+  close(fd);
+
+  return code;
+}
+
+exit_code_t main(uint64_t argc, const char **argv) {
+  if (argc == 1) {
+    return pass(0);
+  }
+
+  uint64_t code = EXIT_CODE_OK;
+  for (uint64_t i = 1; i < argc; i++) {
+    exit_code_t c = wc(argv[i]);
+    if (c != EXIT_CODE_OK) {
+      code = c;
+    }
+  }
+
+  return code;
+}

src/user/syscall.asm

@@ -3,65 +3,83 @@ bits 64
 global read
 read:
     mov rax, 0
+    mov r10, rcx
     syscall
     ret
 
 global write
 write:
     mov rax, 1
+    mov r10, rcx
     syscall
     ret
 
 global getcwd
 getcwd:
     mov rax, 2
+    mov r10, rcx
     syscall
     ret
 
 global chdir
 chdir:
     mov rax, 3
+    mov r10, rcx
     syscall
     ret
 
 global spawn
 spawn:
     mov rax, 4
+    mov r10, rcx
     syscall
     ret
 
 global waitpid
 waitpid:
     mov rax, 5
+    mov r10, rcx
     syscall
     ret
 
 global open
 open:
     mov rax, 6
+    mov r10, rcx
     syscall
     ret
 
 global close
 close:
     mov rax, 7
+    mov r10, rcx
     syscall
     ret
 
 global truncate
 truncate:
     mov rax, 8
+    mov r10, rcx
     syscall
     ret
 
 global remove
 remove:
     mov rax, 9
+    mov r10, rcx
+    syscall
+    ret
+
+global pipe
+pipe:
+    mov rax, 10
+    mov r10, rcx
     syscall
     ret
 
 global exit
 exit:
     mov rax, 60
+    mov r10, rcx
     syscall
     ; never returns

src/user/syscall.h

@@ -10,7 +10,7 @@ uint64_t getcwd(uint64_t max, void *to);
 
 uint64_t chdir(const char *path);
 
-uint64_t spawn(const char *path, uint64_t argc, const char **argv);
+uint64_t spawn(const char *path, uint64_t argc, const char **argv, uint64_t stdin, uint64_t stdout);
 
 exit_code_t waitpid(uint64_t pid);
 
@@ -22,4 +22,6 @@ uint64_t truncate(uint64_t fd, uint64_t size);
 
 uint64_t remove(const char *path);
 
+uint64_t pipe(uint64_t *write_fd, uint64_t *read_fd);
+
 void exit(exit_code_t code);