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#include "file.h"
#include <camellia/syscalls.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static FILE _stdin_null = { .fd = 0 };
static FILE _stdout_null = { .fd = 1 };
static FILE _stderr_null = { .fd = 2 };
FILE *const stdin = &_stdin_null;
FILE *const stdout = &_stdout_null;
FILE *const stderr = &_stderr_null;
FILE *fopen(const char *path, const char *mode) {
FILE *f;
handle_t h;
int flags = 0;
if (path && path[0] == '!') {
/* special handling for "!files" */
path++;
if (!strcmp(path, "stdin")) return file_clone(stdin, mode);
if (!strcmp(path, "stdout")) return file_clone(stdout, mode);
if (!strcmp(path, "stderr")) return file_clone(stderr, mode);
errno = -1;
return NULL;
} else {
if (mode[0] == 'w' || mode[0] == 'a')
flags |= OPEN_CREATE;
h = _syscall_open(path, strlen(path), flags);
if (h < 0) {
errno = -h;
return NULL;
}
if (mode[0] == 'w')
_syscall_write(h, NULL, 0, 0, WRITE_TRUNCATE);
f = fdopen(h, mode);
if (!f) close(h);
return f;
}
}
FILE *freopen(const char *path, const char *mode, FILE *f) {
/* partially based on the musl implementation of freopen */
FILE *f2;
if (!path) goto fail;
f2 = fopen(path, mode);
if (!f2) goto fail;
if (f->fd == f2->fd) {
f2->fd = -1;
} else {
if (_syscall_dup(f2->fd, f->fd, 0) < 0) goto fail2;
}
f->pos = f2->pos;
f->eof = f2->eof;
fclose(f2);
return f;
fail2:
fclose(f2);
fail:
fclose(f);
return NULL;
}
FILE *fdopen(int fd, const char *mode) {
FILE *f;
f = malloc(sizeof *f);
if (!f) return NULL;
f->pos = mode[0] == 'a' ? -1 : 0;
f->eof = false;
f->fd = fd;
f->error = false;
return f;
}
FILE *file_clone(const FILE *f, const char *mode) {
handle_t h = _syscall_dup(f->fd, -1, 0);
FILE *f2;
if (h < 0) return NULL;
f2 = fdopen(h, mode);
if (!f2) {
close(h);
return NULL;
}
f2->pos = f->pos;
f2->eof = f->eof;
f2->fd = h;
return f2;
}
static void fadvance(long amt, FILE *f) {
bool pos_neg = f->pos < 0;
f->pos += amt;
if (pos_neg && f->pos >= 0)
f->pos = -1;
}
size_t fread(void *restrict ptr, size_t size, size_t nitems, FILE *restrict f) {
size_t total = size*nitems, pos = 0;
unsigned char *buf = ptr;
if (f->fd < 0) {
errno = EBADF;
return 0;
}
if (size == 0)
return 0;
while (pos < total) {
long res = _syscall_read(f->fd, buf + pos, total - pos, f->pos);
if (res < 0) {
f->error = true;
errno = -res;
return pos/size;
} else if (res == 0) {
f->eof = true;
return pos/size;
} else {
pos += res;
fadvance(res, f);
}
}
return nitems;
}
size_t fwrite(const void *restrict ptr, size_t size, size_t nitems, FILE *restrict f) {
size_t total = size*nitems, pos = 0;
const unsigned char *buf = ptr;
if (f->fd < 0) {
errno = EBADF;
return 0;
}
if (size == 0)
return 0;
while (pos < total) {
long res = _syscall_write(f->fd, buf + pos, total - pos, f->pos, 0);
if (res < 0) {
f->error = true;
errno = -res;
return pos/size;
} else if (res == 0) {
f->eof = true;
return pos/size;
} else {
pos += res;
fadvance(res, f);
}
}
return nitems;
}
char *fgets(char *buf, int size, FILE *f) {
char c = '\0';
long pos = 0;
while (pos < (size-1) && c != '\n' && fread(&c, 1, 1, f))
buf[pos++] = c;
buf[pos++] = '\0';
if (f->eof && pos == 1) return NULL;
if (f->error) return NULL;
return buf;
}
int fseek(FILE *f, long offset, int whence) {
if (fflush(f))
return -1;
switch (whence) {
case SEEK_SET:
f->pos = 0;
break;
case SEEK_CUR:
break;
case SEEK_END:
f->pos = -1;
break;
default:
errno = EINVAL;
return -1;
}
bool pos_neg = f->pos < 0;
f->pos += offset;
if (pos_neg && f->pos >= 0) {
// TODO getting the file size
errno = ENOSYS;
return -1;
}
f->eof = false;
return 0;
}
int fclose(FILE *f) {
fflush(f);
if (f->fd > 0) close(f->fd);
if (f != &_stdin_null && f != &_stdout_null && f != &_stderr_null)
free(f);
return 0;
}
int fflush(FILE *f) {
(void)f;
return 0;
}
int feof(FILE *f) {
return f->eof;
}
int ferror(FILE *f) {
return f->error;
}
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