Implement errno in LibC.

This also meant I had to implement BSS (SHT_NOBITS) sections in ELFLoader.
I also added an strerror() so we can print out what the errors are.
This commit is contained in:
Andreas Kling 2018-10-25 12:06:00 +02:00
parent 434b6a8688
commit 260b14e505
14 changed files with 209 additions and 27 deletions

View file

@ -56,6 +56,22 @@ bool ELFLoader::layout()
m_sections.set(section.name(), move(ptr));
return true;
});
m_image->forEachSectionOfType(SHT_NOBITS, [this, &failed] (const ELFImage::Section& section) {
#ifdef ELFLOADER_DEBUG
kprintf("[ELFLoader] Allocating nobits section: %s\n", section.name());
#endif
if (!section.size())
return true;
char* ptr = m_execSpace.allocateArea(section.name(), section.size());
if (!ptr) {
kprintf("ELFLoader: failed to allocate section '%s'\n", section.name());
failed = true;
return false;
}
memset(ptr, 0, section.size());
m_sections.set(section.name(), move(ptr));
return true;
});
return !failed;
}

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@ -9,6 +9,7 @@
#include <VirtualFileSystem/VirtualFileSystem.h>
#include <ELFLoader/ExecSpace.h>
#include "MemoryManager.h"
#include "errno.h"
//#define DEBUG_IO
//#define TASK_DEBUG
@ -166,25 +167,32 @@ int Task::sys$munmap(void* addr, size_t size)
int Task::sys$spawn(const char* path)
{
auto* child = Task::createUserTask(path, m_uid, m_gid, m_pid);
int error = 0;
auto* child = Task::createUserTask(path, m_uid, m_gid, m_pid, error);
if (child)
return child->pid();
return -1;
return error;
}
Task* Task::createUserTask(const String& path, uid_t uid, gid_t gid, pid_t parentPID)
Task* Task::createUserTask(const String& path, uid_t uid, gid_t gid, pid_t parentPID, int& error)
{
auto parts = path.split('/');
if (parts.isEmpty())
if (parts.isEmpty()) {
error = -ENOENT;
return nullptr;
}
auto handle = VirtualFileSystem::the().open(path);
if (!handle)
if (!handle) {
error = -ENOENT; // FIXME: Get a more detailed error from VFS.
return nullptr;
}
auto elfData = handle->readEntireFile();
if (!elfData)
if (!elfData) {
error = -EIO; // FIXME: Get a more detailed error from VFS.
return nullptr;
}
InterruptDisabler disabler; // FIXME: Get rid of this, jesus christ. This "critical" section is HUGE.
Task* t = new Task(parts.takeLast(), uid, gid, parentPID, Ring3);
@ -203,12 +211,14 @@ Task* Task::createUserTask(const String& path, uid_t uid, gid_t gid, pid_t paren
if (!success) {
delete t;
kprintf("Failure loading ELF %s\n", path.characters());
error = -ENOEXEC;
return nullptr;
}
t->m_tss.eip = (dword)space.symbolPtr("_start");
if (!t->m_tss.eip) {
delete t;
error = -ENOEXEC;
return nullptr;
}
@ -221,6 +231,7 @@ Task* Task::createUserTask(const String& path, uid_t uid, gid_t gid, pid_t paren
kprintf("Task %u (%s) spawned @ %p\n", t->pid(), t->name().characters(), t->m_tss.eip);
#endif
error = 0;
return t;
}
@ -758,11 +769,6 @@ Task* Task::kernelTask()
return s_kernelTask;
}
void Task::setError(int error)
{
m_error = error;
}
Task::Region::Region(LinearAddress a, size_t s, RetainPtr<Zone>&& z, String&& n)
: linearAddress(a)
, size(s)

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@ -16,7 +16,7 @@ class Task : public InlineLinkedListNode<Task> {
friend class InlineLinkedListNode<Task>;
public:
static Task* createKernelTask(void (*entry)(), String&& name);
static Task* createUserTask(const String& path, uid_t, gid_t, pid_t parentPID);
static Task* createUserTask(const String& path, uid_t, gid_t, pid_t parentPID, int& error);
~Task();
static Vector<Task*> allTasks();
@ -100,7 +100,6 @@ public:
int sys$getcwd(char*, size_t);
static void initialize();
void setError(int);
static void taskDidCrash(Task*);

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38
Kernel/errno.h Normal file
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@ -0,0 +1,38 @@
#pragma once
#define EPERM 1 // Operation not permitted
#define ENOENT 2 // No such file or directory
#define ESRCH 3 // No such process
#define EINTR 4 // Interrupted system call
#define EIO 5 // I/O error
#define ENXIO 6 // No such device or address
#define E2BIG 7 // Argument list too long
#define ENOEXEC 8 // Exec format error
#define EBADF 9 // Bad file number
#define ECHILD 10 // No child processes
#define EAGAIN 11 // Try again
#define ENOMEM 12 // Out of memory
#define EACCES 13 // Permission denied
#define EFAULT 14 // Bad address
#define ENOTBLK 15 // Block device required
#define EBUSY 16 // Device or resource busy
#define EEXIST 17 // File exists
#define EXDEV 18 // Cross-device link
#define ENODEV 19 // No such device
#define ENOTDIR 20 // Not a directory
#define EISDIR 21 // Is a directory
#define EINVAL 22 // Invalid argument
#define ENFILE 23 // File table overflow
#define EMFILE 24 // Too many open files
#define ENOTTY 25 // Not a typewriter
#define ETXTBSY 26 // Text file busy
#define EFBIG 27 // File too large
#define ENOSPC 28 // No space left on device
#define ESPIPE 29 // Illegal seek
#define EROFS 30 // Read-only file system
#define EMLINK 31 // Too many links
#define EPIPE 32 // Broken pipe
#define EDOM 33 // Math argument out of domain of func
#define ERANGE 34 // Math result not representable
#define EOVERFLOW 75 // Value too large for defined data type

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@ -140,7 +140,8 @@ static void init_stage2()
dword lastAlloc = sum_alloc;
for (unsigned i = 0; i < 100; ++i) {
auto* shTask = Task::createUserTask("/bin/id", (uid_t)100, (gid_t)100, (pid_t)0);
int error;
auto* shTask = Task::createUserTask("/bin/id", (uid_t)100, (gid_t)100, (pid_t)0, error);
kprintf("malloc stats: alloc:%u free:%u\n", sum_alloc, sum_free);
kprintf("sizeof(Task):%u\n", sizeof(Task));
kprintf("delta:%u\n",sum_alloc - lastAlloc);
@ -149,7 +150,8 @@ static void init_stage2()
}
#endif
auto* shTask = Task::createUserTask("/bin/sh", (uid_t)100, (gid_t)100, (pid_t)0);
int error;
auto* shTask = Task::createUserTask("/bin/sh", (uid_t)100, (gid_t)100, (pid_t)0, error);
banner();

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@ -2,8 +2,12 @@
extern "C" int main(int, char**);
int errno;
extern "C" int _start()
{
errno = 0;
// FIXME: Pass appropriate argc/argv.
int status = main(0, nullptr);

57
LibC/errno.h Normal file
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@ -0,0 +1,57 @@
#pragma once
#define EPERM 1 // Operation not permitted
#define ENOENT 2 // No such file or directory
#define ESRCH 3 // No such process
#define EINTR 4 // Interrupted system call
#define EIO 5 // I/O error
#define ENXIO 6 // No such device or address
#define E2BIG 7 // Argument list too long
#define ENOEXEC 8 // Exec format error
#define EBADF 9 // Bad file number
#define ECHILD 10 // No child processes
#define EAGAIN 11 // Try again
#define ENOMEM 12 // Out of memory
#define EACCES 13 // Permission denied
#define EFAULT 14 // Bad address
#define ENOTBLK 15 // Block device required
#define EBUSY 16 // Device or resource busy
#define EEXIST 17 // File exists
#define EXDEV 18 // Cross-device link
#define ENODEV 19 // No such device
#define ENOTDIR 20 // Not a directory
#define EISDIR 21 // Is a directory
#define EINVAL 22 // Invalid argument
#define ENFILE 23 // File table overflow
#define EMFILE 24 // Too many open files
#define ENOTTY 25 // Not a typewriter
#define ETXTBSY 26 // Text file busy
#define EFBIG 27 // File too large
#define ENOSPC 28 // No space left on device
#define ESPIPE 29 // Illegal seek
#define EROFS 30 // Read-only file system
#define EMLINK 31 // Too many links
#define EPIPE 32 // Broken pipe
#define EDOM 33 // Math argument out of domain of func
#define ERANGE 34 // Math result not representable
#define EOVERFLOW 75 // Value too large for defined data type
#define __RETURN_WITH_ERRNO(rc, good_ret, bad_ret) \
do { \
if (rc < 0) { \
errno = -rc; \
return (bad_ret); \
} else { \
errno = 0; \
return (good_ret); \
} \
} while(0)
extern "C" {
extern int errno;
};

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@ -1,16 +1,19 @@
#include "mman.h"
#include "errno.h"
#include <Kernel/Syscall.h>
extern "C" {
void* mmap(void* addr, size_t size)
{
return (void*)Syscall::invoke(Syscall::PosixMmap, (dword)addr, (dword)size);
int rc = Syscall::invoke(Syscall::PosixMmap, (dword)addr, (dword)size);
__RETURN_WITH_ERRNO(rc, (void*)rc, (void*)-1);
}
int munmap(void* addr, size_t size)
{
return Syscall::invoke(Syscall::PosixMunmap, (dword)addr, (dword)size);
int rc = Syscall::invoke(Syscall::PosixMunmap, (dword)addr, (dword)size);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
}

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@ -1,11 +1,13 @@
#include "process.h"
#include "errno.h"
#include <Kernel/Syscall.h>
extern "C" {
int spawn(const char* path)
{
return Syscall::invoke(Syscall::Spawn, (dword)path);
int rc = Syscall::invoke(Syscall::Spawn, (dword)path);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
}

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@ -1,4 +1,6 @@
#include "string.h"
#include "errno.h"
#include "stdio.h"
extern "C" {
@ -10,5 +12,49 @@ size_t strlen(const char* str)
return len;
}
const char* strerror(int errnum)
{
switch (errnum) {
case 0: return "No error";
case EPERM: return "Operation not permitted";
case ENOENT: return "No such file or directory";
case ESRCH: return "No such process";
case EINTR: return "Interrupted syscall";
case EIO: return "I/O error";
case ENXIO: return "No such device/address";
case E2BIG: return "Argument list too long";
case ENOEXEC: return "Exec format error";
case EBADF: return "Bad fd number";
case ECHILD: return "No child processes";
case EAGAIN: return "Try again";
case ENOMEM: return "Out of memory";
case EACCES: return "Access denied";
case EFAULT: return "Bad address";
case ENOTBLK: return "Not a block device";
case EBUSY: return "Resource busy";
case EEXIST: return "File already exists";
case EXDEV: return "Cross-device link";
case ENODEV: return "No such device";
case ENOTDIR: return "Not a directory";
case EISDIR: return "Is a directory";
case EINVAL: return "Invalid argument";
case ENFILE: return "File table overflow";
case EMFILE: return "Too many open files";
case ENOTTY: return "Not a TTY";
case ETXTBSY: return "Text file busy";
case EFBIG: return "File too big";
case ENOSPC: return "No space left";
case ESPIPE: return "Illegal seek";
case EROFS: return "File system is read-only";
case EMLINK: return "Too many links";
case EPIPE: return "Broken pipe";
case EDOM: return "Math argument out of domain";
case ERANGE: return "Math result not representable";
case EOVERFLOW: return "Value too large for data type";
}
printf("strerror() missing string for errnum=%d\n", errnum);
return "Unknown error";
}
}

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@ -5,6 +5,7 @@
extern "C" {
size_t strlen(const char*);
const char* strerror(int errnum);
}

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@ -1,5 +1,6 @@
#include "unistd.h"
#include "string.h"
#include "errno.h"
#include <Kernel/Syscall.h>
extern "C" {
@ -22,35 +23,38 @@ pid_t getpid()
int open(const char* path)
{
size_t length = strlen(path);
return Syscall::invoke(Syscall::PosixOpen, (dword)path, (dword)length);
int rc = Syscall::invoke(Syscall::PosixOpen, (dword)path, (dword)length);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
ssize_t read(int fd, void* buf, size_t count)
{
return Syscall::invoke(Syscall::PosixRead, (dword)fd, (dword)buf, (dword)count);
int rc = Syscall::invoke(Syscall::PosixRead, (dword)fd, (dword)buf, (dword)count);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int close(int fd)
{
return Syscall::invoke(Syscall::PosixClose, fd);
int rc = Syscall::invoke(Syscall::PosixClose, fd);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
pid_t waitpid(pid_t waitee)
{
return Syscall::invoke(Syscall::PosixWaitpid, waitee);
int rc = Syscall::invoke(Syscall::PosixWaitpid, waitee);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int lstat(const char* path, stat* statbuf)
{
return Syscall::invoke(Syscall::PosixLstat, (dword)path, (dword)statbuf);
int rc = Syscall::invoke(Syscall::PosixLstat, (dword)path, (dword)statbuf);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
char* getcwd(char* buffer, size_t size)
{
int rc = Syscall::invoke(Syscall::PosixGetcwd, (dword)buffer, (dword)size);
if (rc != 0)
return nullptr;
return buffer;
__RETURN_WITH_ERRNO(rc, buffer, nullptr);
}
}

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@ -1,6 +1,8 @@
#include <LibC/stdio.h>
#include <LibC/unistd.h>
#include <LibC/process.h>
#include <LibC/errno.h>
#include <LibC/string.h>
static void prompt()
{
@ -12,12 +14,14 @@ static void prompt()
static int runcmd(char* cmd)
{
if (cmd[0] == 0)
return 0;
//printf("command: '%s'\n", cmd);
char buf[128];
sprintf(buf, "/bin/%s", cmd);
int ret = spawn(buf);
if (ret == -1) {
printf("spawn failed: %s\n", cmd);
printf("spawn failed: %s (%s)\n", cmd, strerror(errno));
return 1;
}
waitpid(ret);