Support putting the root filesystem in a directory

Also added repz cmpsb, support for executing dynamic libraries, set_tid_address stub, and found an alternative to setup.c.
kenardi · Jul 24, 2017 · 3e590e9 · 3e590e9
1 parent bb38231
commit 3e590e9
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Showing 23 changed files with 326 additions and 171 deletions.
diff --git a/emu/decode.h b/emu/decode.h
@@ -618,6 +618,8 @@ int CONCAT(decoder_name, OP_SIZE)(struct cpu_state *cpu) {
                 case 0xa4: TRACEI("rep movsb"); REP(MOVS(8)); break;
                 case 0xa5: TRACEI("rep movs"); REP(MOVS(OP_SIZE)); break;
 
+                case 0xa6: TRACEI("repz cmpsb"); REPZ(CMPS(8)); break;
+
                 case 0xaa: TRACEI("rep stosb"); REP(STOS(8)); break;
                 case 0xab: TRACEI("rep stos"); REP(STOS(OP_SIZE)); break;
 

diff --git a/emu/interp.c b/emu/interp.c
@@ -85,6 +85,11 @@
 #define get_mem_addr(size) mem_read(addr, size)
 #define set_mem_addr(to, size) mem_write(addr, to, size)
 
+#define get_mem_si(size) mem_read(cpu->osi, size)
+#define set_mem_si(size) mem_write(cpu->osi, size)
+#define get_mem_di(size) mem_read(cpu->odi, size)
+#define set_mem_di(size) mem_write(cpu->osi, size)
+
 // DEFINE ALL THE MACROS
 #define get_oax(size) cpu->oax
 #define get_obx(size) cpu->obx
@@ -439,9 +444,13 @@
 
 // TODO find an alternative to al here
 #define SCAS(z) \
-    addr = cpu->edi; CMP(al, mem_addr,z); \
+    CMP(al, mem_di,z); \
     BUMP_DI(z)
 
+#define CMPS(z) \
+    CMP(mem_di, mem_si,z); \
+    BUMP_SI_DI(z)
+
 #define REP(OP) \
     while (cpu->ocx != 0) { \
         OP; \
@@ -455,6 +464,13 @@
         if (ZF) break; \
     }
 
+#define REPZ(OP) \
+    while (cpu->ocx != 0) { \
+        OP; \
+        cpu->ocx--; \
+        if (!ZF) break; \
+    }
+
 #define CMPXCHG(src, dst,z) \
     CMP(oax, dst,z); \
     if (E) { \

diff --git a/fs/generic.c b/fs/generic.c
@@ -4,28 +4,34 @@
 #include "sys/fs.h"
 #include "sys/process.h"
 
-struct mount *find_mount(char *pathname) {
+static struct mount *find_mount(char *pathname) {
     struct mount *mount;
     for (mount = mounts; mount != NULL; mount = mount->next) {
-        if (strncmp(pathname, mount->mount_point, strlen(mount->mount_point)) == 0) {
+        if (strncmp(pathname, mount->point, strlen(mount->point)) == 0) {
             break;
         }
     }
     assert(mount != NULL); // this would mean there's no root FS mounted
     return mount;
 }
 
-char *path_in_mount(char *path, struct mount *mount) {
-    return path + strlen(mount->mount_point);
+struct mount *find_mount_and_trim_path(char *path) {
+    struct mount *mount = find_mount(path);
+    char *dst = path;
+    const char *src = path + strlen(mount->point);
+    while (*src != '\0')
+        *dst++ = *src++;
+    *dst = '\0';
+    return mount;
 }
 
 int generic_open(const char *pathname, struct fd *fd, int flags, int mode) {
     char path[MAX_PATH];
     int err = path_normalize(pathname, path);
     if (err < 0)
         return err;
-    struct mount *mount = find_mount(path);
-    return mount->fs->open(path_in_mount(path, mount), fd, flags, mode);
+    struct mount *mount = find_mount_and_trim_path(path);
+    return mount->fs->open(mount, path, fd, flags, mode);
 }
 
 // TODO I bet this can be shorter
@@ -34,8 +40,8 @@ int generic_access(const char *pathname, int mode) {
     int err = path_normalize(pathname, path);
     if (err < 0)
         return err;
-    struct mount *mount = find_mount(path);
-    return mount->fs->access(path_in_mount(path, mount), mode);
+    struct mount *mount = find_mount_and_trim_path(path);
+    return mount->fs->access(mount, path, mode);
 }
 
 // TODO I bet this can be shorter
@@ -44,22 +50,15 @@ int generic_unlink(const char *pathname) {
     int err = path_normalize(pathname, path);
     if (err < 0)
         return err;
-    struct mount *mount = find_mount(path);
-    return mount->fs->unlink(path_in_mount(path, mount));
+    struct mount *mount = find_mount_and_trim_path(path);
+    return mount->fs->unlink(mount, path);
 }
 
 ssize_t generic_readlink(const char *pathname, char *buf, size_t bufsize) {
     char path[MAX_PATH];
     int err = path_normalize(pathname, path);
     if (err < 0)
         return err;
-    struct mount *mount = find_mount(path);
-    return mount->fs->readlink(path_in_mount(path, mount), buf, bufsize);
-}
-
-void mount_root() {
-    mounts = malloc(sizeof(struct mount));
-    mounts->mount_point = strdup("");
-    mounts->fs = &realfs;
-    mounts->next = NULL;
+    struct mount *mount = find_mount_and_trim_path(path);
+    return mount->fs->readlink(mount, path, buf, bufsize);
 }
diff --git a/fs/real.c b/fs/real.c
@@ -12,10 +12,27 @@
 #include "sys/calls.h"
 #include "sys/fs.h"
 
+char *strnprepend(char *str, const char *prefix, int max) {
+    if (strlen(str) + strlen(prefix) + 1 > max)
+        return NULL;
+    const char *src = str + strlen(str) + 1;
+    char *dst = (char *) src + strlen(prefix);
+    while (src != str)
+        *dst-- = *src--;
+    *dst = *src;
+    src = prefix;
+    dst = str;
+    while (*src != '\0')
+        *dst++ = *src++;
+    return str;
+}
+
 // TODO translate goddamn flags
 
-static int realfs_open(char *path, struct fd *fd, int flags, int mode) {
-    /* debugger; */
+static int realfs_open(struct mount *mount, char *path, struct fd *fd, int flags, int mode) {
+    if (strnprepend(path, mount->source, MAX_PATH) == NULL)
+        return _ENAMETOOLONG;
+
     int fd_no = open(path, flags, mode);
     if (fd_no < 0)
         return err_map(errno);
@@ -80,9 +97,17 @@ static void copy_xattr_stat(struct statbuf *fake_stat, struct xattr_stat *xstat)
     fake_stat->rdev = xstat->rdev;
 }
 
-static int realfs_stat(const char *path, struct statbuf *fake_stat, bool follow_links) {
+static int realfs_stat(struct mount *mount, char *path, struct statbuf *fake_stat, bool follow_links) {
+    if (strnprepend(path, mount->source, MAX_PATH) == NULL)
+        return _ENAMETOOLONG;
+
     struct stat real_stat;
-    if ((follow_links ? lstat : stat)(path, &real_stat) < 0)
+    int (*stat_fn)(const char *path, struct stat *buf);
+    if (follow_links)
+        stat_fn = lstat;
+    else
+        stat_fn = stat;
+    if (stat_fn(path, &real_stat) < 0)
         return err_map(errno);
     copy_stat(fake_stat, &real_stat);
 
@@ -104,14 +129,20 @@ static int realfs_fstat(struct fd *fd, struct statbuf *fake_stat) {
     return 0;
 }
 
-static int realfs_unlink(const char *path) {
+static int realfs_unlink(struct mount *mount, char *path) {
+    if (strnprepend(path, mount->source, MAX_PATH) == NULL)
+        return _ENAMETOOLONG;
+
     int res = unlink(path);
     if (res < 0)
         return err_map(errno);
     return res;
 }
 
-static int realfs_access(const char *path, int mode) {
+static int realfs_access(struct mount *mount, char *path, int mode) {
+    if (strnprepend(path, mount->source, MAX_PATH) == NULL)
+        return _ENAMETOOLONG;
+
     int real_mode = 0;
     if (mode & AC_F) real_mode |= F_OK;
     if (mode & AC_R) real_mode |= R_OK;
@@ -123,14 +154,14 @@ static int realfs_access(const char *path, int mode) {
     return res;
 }
 
-static ssize_t realfs_read(struct fd *fd, char *buf, size_t bufsize) {
+static ssize_t realfs_read(struct fd *fd, void *buf, size_t bufsize) {
     ssize_t res = read(fd->real_fd, buf, bufsize);
     if (res < 0)
         return err_map(errno);
     return res;
 }
 
-static ssize_t realfs_write(struct fd *fd, char *buf, size_t bufsize) {
+static ssize_t realfs_write(struct fd *fd, void *buf, size_t bufsize) {
     ssize_t res = write(fd->real_fd, buf, bufsize);
     if (res < 0)
         return err_map(errno);
@@ -252,7 +283,10 @@ static int realfs_ioctl(struct fd *fd, int cmd, void *arg) {
     return res;
 }
 
-static ssize_t realfs_readlink(char *path, char *buf, size_t bufsize) {
+static ssize_t realfs_readlink(struct mount *mount, char *path, char *buf, size_t bufsize) {
+    if (strnprepend(path, mount->source, MAX_PATH) == NULL)
+        return _ENAMETOOLONG;
+
     ssize_t size = readlink(path, buf, bufsize);
     if (size < 0)
         return err_map(errno);

diff --git a/fs/stat.c b/fs/stat.c
@@ -32,8 +32,8 @@ int generic_stat(const char *pathname, struct statbuf *stat, bool follow_links)
     int err = path_normalize(pathname, path);
     if (err < 0)
         return err;
-    struct mount *mount = find_mount(path);
-    return mount->fs->stat(path_in_mount(path, mount), stat, follow_links);
+    struct mount *mount = find_mount_and_trim_path(path);
+    return mount->fs->stat(mount, path, stat, follow_links);
 }
 
 static dword_t sys_stat_path(addr_t pathname_addr, addr_t statbuf_addr, bool follow_links) {

diff --git a/main.c b/main.c
@@ -1,13 +1,11 @@
 #include <stdlib.h>
 #include "sys/calls.h"
 #include "sys/process.h"
+#include "xX_main_Xx.h"
 
 int main(int argc, char *const argv[]) {
-    int err;
-    setup();
-    char *envp[] = {NULL};
-    if ((err = sys_execve(argv[1], argv + 1, envp)) < 0) {
-        return -err;
-    }
+    int err = xX_main_Xx(argc, argv);
+    if (err < 0)
+        return err;
     cpu_run(&current->cpu);
 }
diff --git a/meson.build b/meson.build
@@ -49,7 +49,7 @@ emu_src = [
 
 threads = dependency('threads')
 
-libish = library('ish', sys_src + emu_src + ['setup.c'],
+libish = library('ish', sys_src + emu_src,
     include_directories: includes)
 ish = declare_dependency(
     link_with: libish,

diff --git a/misc.h b/misc.h
@@ -60,6 +60,4 @@ typedef sdword_t int_t;
 #define uint(size) CONCAT3(uint,size,_t)
 #define sint(size) CONCAT3(int,size,_t)
 
-void setup();
-
 #endif
diff --git a/setup.c b/setup.c
diff --git a/sys/calls.c b/sys/calls.c
@@ -54,6 +54,7 @@ syscall_t syscall_table[] = {
     [239] = (syscall_t) sys_sendfile64,
     [243] = (syscall_t) sys_set_thread_area,
     [252] = (syscall_t) sys_exit_group,
+    [258] = (syscall_t) sys_set_tid_address,
     [265] = (syscall_t) sys_clock_gettime,
 
     // stubs

diff --git a/sys/calls.h b/sys/calls.h
@@ -83,6 +83,7 @@ dword_t sys_getgid32();
 dword_t sys_getgid();
 dword_t sys_getcwd(addr_t buf_addr, dword_t size);
 int sys_set_thread_area(addr_t u_info);
+int sys_set_tid_address(addr_t blahblahblah);
 
 // system information
 #define UNAME_LENGTH 65

diff --git a/sys/elf.h b/sys/elf.h
@@ -10,6 +10,7 @@
 #define ELF_BIGENDIAN 2
 #define ELF_LINUX_ABI 3
 #define ELF_EXECUTABLE 2
+#define ELF_DYNAMIC 3
 #define ELF_X86 3
 
 struct elf_header {

diff --git a/sys/errno.h b/sys/errno.h
@@ -11,7 +11,7 @@
 #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 _E2BIG         -7 /* That's what she said */
 #define _ENOEXEC       -8 /* Exec format error */
 #define _EBADF         -9 /* Bad file number */
 #define _ECHILD       -10 /* No child processes */