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read/write syscalls: properly handle nbytes = 0

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Matheus
2024-07-30 20:30:55 -03:00
parent ed46c95d59
commit 4a7ccc208c
2 changed files with 10 additions and 8 deletions
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kernel-src/sys/syscalls/read.c
+4 -2
View File
@@ -10,8 +10,9 @@ syscallret_t syscall_read(context_t *context, int fd, void *buffer, size_t size)
.ret = -1 .ret = -1
}; };
void *kernelbuff = vmm_map(NULL, size, VMM_FLAGS_ALLOCATE, ARCH_MMU_FLAGS_READ | ARCH_MMU_FLAGS_WRITE | ARCH_MMU_FLAGS_NOEXEC, NULL); void *kernelbuff = vmm_map(NULL, size == 0 ? 1 : size, VMM_FLAGS_ALLOCATE, ARCH_MMU_FLAGS_READ | ARCH_MMU_FLAGS_WRITE | ARCH_MMU_FLAGS_NOEXEC, NULL);
if (kernelbuff == NULL) { if (kernelbuff == NULL) {
printf("read enomem: %d %p %lu\n", fd, buffer, size);
ret.errno = ENOMEM; ret.errno = ENOMEM;
return ret; return ret;
} }
@@ -28,6 +29,7 @@ syscallret_t syscall_read(context_t *context, int fd, void *buffer, size_t size)
ret.errno = 0; ret.errno = 0;
goto cleanup; goto cleanup;
} }
size_t bytesread; size_t bytesread;
uintmax_t offset = file->offset; uintmax_t offset = file->offset;
ret.errno = vfs_read(file->vnode, kernelbuff, size, file->offset, &bytesread, fileflagstovnodeflags(file->flags)); ret.errno = vfs_read(file->vnode, kernelbuff, size, file->offset, &bytesread, fileflagstovnodeflags(file->flags));
@@ -42,6 +44,6 @@ cleanup:
if (file) if (file)
fd_release(file); fd_release(file);
vmm_unmap(kernelbuff, size, 0); vmm_unmap(kernelbuff, size == 0 ? 1 : size, 0);
return ret; return ret;
} }
kernel-src/sys/syscalls/write.c
+6 -6
View File
@@ -8,7 +8,7 @@ syscallret_t syscall_write(context_t *context, int fd, void *buffer, size_t size
.ret = -1 .ret = -1
}; };
void *kernelbuff = vmm_map(NULL, size, VMM_FLAGS_ALLOCATE, ARCH_MMU_FLAGS_READ | ARCH_MMU_FLAGS_WRITE | ARCH_MMU_FLAGS_NOEXEC, NULL); void *kernelbuff = vmm_map(NULL, size == 0 ? 1 : size, VMM_FLAGS_ALLOCATE, ARCH_MMU_FLAGS_READ | ARCH_MMU_FLAGS_WRITE | ARCH_MMU_FLAGS_NOEXEC, NULL);
if (kernelbuff == NULL) { if (kernelbuff == NULL) {
ret.errno = ENOMEM; ret.errno = ENOMEM;
return ret; return ret;
@@ -21,16 +21,16 @@ syscallret_t syscall_write(context_t *context, int fd, void *buffer, size_t size
goto cleanup; goto cleanup;
} }
ret.errno = usercopy_fromuser(kernelbuff, buffer, size);
if (ret.errno)
goto cleanup;
if (size == 0) { if (size == 0) {
ret.ret = 0; ret.ret = 0;
ret.errno = 0; ret.errno = 0;
goto cleanup; goto cleanup;
} }
ret.errno = usercopy_fromuser(kernelbuff, buffer, size);
if (ret.errno)
goto cleanup;
size_t byteswritten; size_t byteswritten;
uintmax_t offset = file->offset; uintmax_t offset = file->offset;
@@ -55,6 +55,6 @@ cleanup:
if (file) if (file)
fd_release(file); fd_release(file);
vmm_unmap(kernelbuff, size, 0); vmm_unmap(kernelbuff, size == 0 ? 1 : size, 0);
return ret; return ret;
} }