core/ngx_file.c源文件分析(2)
本节我们讲述一下nginx中对所涉及到的文件操作。
1. 函数ngx_conf_set_path_slot()
char *
ngx_conf_set_path_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
char *p = conf;
ssize_t level;
ngx_str_t *value;
ngx_uint_t i, n;
ngx_path_t *path, **slot;
slot = (ngx_path_t **) (p + cmd->offset);
if (*slot) {
return "is duplicate";
}
path = ngx_pcalloc(cf->pool, sizeof(ngx_path_t));
if (path == NULL) {
return NGX_CONF_ERROR;
}
value = cf->args->elts;
path->name = value[1];
if (path->name.data[path->name.len - 1] == '/') {
path->name.len--;
}
if (ngx_conf_full_name(cf->cycle, &path->name, 0) != NGX_OK) {
return NGX_CONF_ERROR;
}
path->conf_file = cf->conf_file->file.name.data;
path->line = cf->conf_file->line;
for (i = 0, n = 2; n < cf->args->nelts; i++, n++) {
level = ngx_atoi(value[n].data, value[n].len);
if (level == NGX_ERROR || level == 0) {
return "invalid value";
}
path->level[i] = level;
path->len += level + 1;
}
if (path->len > 10 + i) {
return "invalid value";
}
*slot = path;
if (ngx_add_path(cf, slot) == NGX_ERROR) {
return NGX_CONF_ERROR;
}
return NGX_CONF_OK;
}对于解析到http模块中的下述指令时会调用本函数进行路径设置：
-
client_body_temp_path
-
fastcgi_temp_path
-
proxy_temp_path
-
scgi_temp_path
-
uwsgi_temp_path
对于一个nginx模块，其一般都有如下结构：
这里先举一个例子，看client_body_temp_path指令的用法，则有助于我们理解ngx_conf_set_path_slot()。该指令的基本语法为：
Syntax: client_body_temp_path path [level1 [level2 [level3]]]; Default: client_body_temp_path client_body_temp; Context: http, server, location
用法举例：
client_body_temp_path /spool/nginx/client_temp 1 2;下面我们再来看ngx_conf_set_path_slot()函数：首先求得path->name全路径；再接着解析每一级level的值；最后调用ngx_add_path()将该slot添加到cycle->paths数组中。
2. 函数ngx_conf_merge_path_value()
char *
ngx_conf_merge_path_value(ngx_conf_t *cf, ngx_path_t **path, ngx_path_t *prev,
ngx_path_init_t *init)
{
if (*path) {
return NGX_CONF_OK;
}
if (prev) {
*path = prev;
return NGX_CONF_OK;
}
*path = ngx_pcalloc(cf->pool, sizeof(ngx_path_t));
if (*path == NULL) {
return NGX_CONF_ERROR;
}
(*path)->name = init->name;
if (ngx_conf_full_name(cf->cycle, &(*path)->name, 0) != NGX_OK) {
return NGX_CONF_ERROR;
}
(*path)->level[0] = init->level[0];
(*path)->level[1] = init->level[1];
(*path)->level[2] = init->level[2];
(*path)->len = init->level[0] + (init->level[0] ? 1 : 0)
+ init->level[1] + (init->level[1] ? 1 : 0)
+ init->level[2] + (init->level[2] ? 1 : 0);
if (ngx_add_path(cf, path) != NGX_OK) {
return NGX_CONF_ERROR;
}
return NGX_CONF_OK;
}本函数较为简单，就是合并prev或者init到path中
3. 函数ngx_conf_set_access_slot()
char *
ngx_conf_set_access_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
char *confp = conf;
u_char *p;
ngx_str_t *value;
ngx_uint_t i, right, shift, *access;
access = (ngx_uint_t *) (confp + cmd->offset);
if (*access != NGX_CONF_UNSET_UINT) {
return "is duplicate";
}
value = cf->args->elts;
*access = 0600;
for (i = 1; i < cf->args->nelts; i++) {
p = value[i].data;
if (ngx_strncmp(p, "user:", sizeof("user:") - 1) == 0) {
shift = 6;
p += sizeof("user:") - 1;
} else if (ngx_strncmp(p, "group:", sizeof("group:") - 1) == 0) {
shift = 3;
p += sizeof("group:") - 1;
} else if (ngx_strncmp(p, "all:", sizeof("all:") - 1) == 0) {
shift = 0;
p += sizeof("all:") - 1;
} else {
goto invalid;
}
if (ngx_strcmp(p, "rw") == 0) {
right = 6;
} else if (ngx_strcmp(p, "r") == 0) {
right = 4;
} else {
goto invalid;
}
*access |= right << shift;
}
return NGX_CONF_OK;
invalid:
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid value \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}这里我们先举个例子，看fastcgi_store_access指令回调本函数时的一个配置：
Syntax: fastcgi_store_access users:permissions ...; Default: fastcgi_store_access user:rw; Context: http, server, location
用法举例：
fastcgi_store_access user:rw group:rw all:r;这里分别用于设置nginx某一文件的访问路径。
4. 函数ngx_add_path()
ngx_int_t
ngx_add_path(ngx_conf_t *cf, ngx_path_t **slot)
{
ngx_uint_t i, n;
ngx_path_t *path, **p;
path = *slot;
p = cf->cycle->paths.elts;
for (i = 0; i < cf->cycle->paths.nelts; i++) {
if (p[i]->name.len == path->name.len
&& ngx_strcmp(p[i]->name.data, path->name.data) == 0)
{
if (p[i]->data != path->data) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"the same path name \"%V\" "
"used in %s:%ui and",
&p[i]->name, p[i]->conf_file, p[i]->line);
return NGX_ERROR;
}
for (n = 0; n < 3; n++) {
if (p[i]->level[n] != path->level[n]) {
if (path->conf_file == NULL) {
if (p[i]->conf_file == NULL) {
ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
"the default path name \"%V\" has "
"the same name as another default path, "
"but the different levels, you need to "
"redefine one of them in http section",
&p[i]->name);
return NGX_ERROR;
}
ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
"the path name \"%V\" in %s:%ui has "
"the same name as default path, but "
"the different levels, you need to "
"define default path in http section",
&p[i]->name, p[i]->conf_file, p[i]->line);
return NGX_ERROR;
}
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"the same path name \"%V\" in %s:%ui "
"has the different levels than",
&p[i]->name, p[i]->conf_file, p[i]->line);
return NGX_ERROR;
}
if (p[i]->level[n] == 0) {
break;
}
}
*slot = p[i];
return NGX_OK;
}
}
p = ngx_array_push(&cf->cycle->paths);
if (p == NULL) {
return NGX_ERROR;
}
*p = path;
return NGX_OK;
}这里在添加slot时，首先检查cycle->paths数组中是否已经有同名的path。如果有则进一步检查path->data、path->level等字段是否一致；否则直接向cycle->paths数组中添加slot。
5. 函数ngx_create_paths()
ngx_int_t
ngx_create_paths(ngx_cycle_t *cycle, ngx_uid_t user)
{
ngx_err_t err;
ngx_uint_t i;
ngx_path_t **path;
path = cycle->paths.elts;
for (i = 0; i < cycle->paths.nelts; i++) {
if (ngx_create_dir(path[i]->name.data, 0700) == NGX_FILE_ERROR) {
err = ngx_errno;
if (err != NGX_EEXIST) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, err,
ngx_create_dir_n " \"%s\" failed",
path[i]->name.data);
return NGX_ERROR;
}
}
if (user == (ngx_uid_t) NGX_CONF_UNSET_UINT) {
continue;
}
#if !(NGX_WIN32)
{
ngx_file_info_t fi;
if (ngx_file_info((const char *) path[i]->name.data, &fi)
== NGX_FILE_ERROR)
{
ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
ngx_file_info_n " \"%s\" failed", path[i]->name.data);
return NGX_ERROR;
}
if (fi.st_uid != user) {
if (chown((const char *) path[i]->name.data, user, -1) == -1) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
"chown(\"%s\", %d) failed",
path[i]->name.data, user);
return NGX_ERROR;
}
}
if ((fi.st_mode & (S_IRUSR|S_IWUSR|S_IXUSR))
!= (S_IRUSR|S_IWUSR|S_IXUSR))
{
fi.st_mode |= (S_IRUSR|S_IWUSR|S_IXUSR);
if (chmod((const char *) path[i]->name.data, fi.st_mode) == -1) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
"chmod() \"%s\" failed", path[i]->name.data);
return NGX_ERROR;
}
}
}
#endif
}
return NGX_OK;
}这里遍历创建cycle->paths数组中的每一个目录，然后修改目录的访问权限为0700，所有者为user。
6. 函数ngx_ext_rename_file()
ngx_int_t
ngx_ext_rename_file(ngx_str_t *src, ngx_str_t *to, ngx_ext_rename_file_t *ext)
{
u_char *name;
ngx_err_t err;
ngx_copy_file_t cf;
#if !(NGX_WIN32)
if (ext->access) {
if (ngx_change_file_access(src->data, ext->access) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_CRIT, ext->log, ngx_errno,
ngx_change_file_access_n " \"%s\" failed", src->data);
err = 0;
goto failed;
}
}
#endif
if (ext->time != -1) {
if (ngx_set_file_time(src->data, ext->fd, ext->time) != NGX_OK) {
ngx_log_error(NGX_LOG_CRIT, ext->log, ngx_errno,
ngx_set_file_time_n " \"%s\" failed", src->data);
err = 0;
goto failed;
}
}
if (ngx_rename_file(src->data, to->data) != NGX_FILE_ERROR) {
return NGX_OK;
}
err = ngx_errno;
if (err == NGX_ENOPATH) {
if (!ext->create_path) {
goto failed;
}
err = ngx_create_full_path(to->data, ngx_dir_access(ext->path_access));
if (err) {
ngx_log_error(NGX_LOG_CRIT, ext->log, err,
ngx_create_dir_n " \"%s\" failed", to->data);
err = 0;
goto failed;
}
if (ngx_rename_file(src->data, to->data) != NGX_FILE_ERROR) {
return NGX_OK;
}
err = ngx_errno;
}
#if (NGX_WIN32)
if (err == NGX_EEXIST || err == NGX_EEXIST_FILE) {
err = ngx_win32_rename_file(src, to, ext->log);
if (err == 0) {
return NGX_OK;
}
}
#endif
if (err == NGX_EXDEV) {
cf.size = -1;
cf.buf_size = 0;
cf.access = ext->access;
cf.time = ext->time;
cf.log = ext->log;
name = ngx_alloc(to->len + 1 + 10 + 1, ext->log);
if (name == NULL) {
return NGX_ERROR;
}
(void) ngx_sprintf(name, "%*s.%010uD%Z", to->len, to->data,
(uint32_t) ngx_next_temp_number(0));
if (ngx_copy_file(src->data, name, &cf) == NGX_OK) {
if (ngx_rename_file(name, to->data) != NGX_FILE_ERROR) {
ngx_free(name);
if (ngx_delete_file(src->data) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_CRIT, ext->log, ngx_errno,
ngx_delete_file_n " \"%s\" failed",
src->data);
return NGX_ERROR;
}
return NGX_OK;
}
ngx_log_error(NGX_LOG_CRIT, ext->log, ngx_errno,
ngx_rename_file_n " \"%s\" to \"%s\" failed",
name, to->data);
if (ngx_delete_file(name) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_CRIT, ext->log, ngx_errno,
ngx_delete_file_n " \"%s\" failed", name);
}
}
ngx_free(name);
err = 0;
}
failed:
if (ext->delete_file) {
if (ngx_delete_file(src->data) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_CRIT, ext->log, ngx_errno,
ngx_delete_file_n " \"%s\" failed", src->data);
}
}
if (err) {
ngx_log_error(NGX_LOG_CRIT, ext->log, err,
ngx_rename_file_n " \"%s\" to \"%s\" failed",
src->data, to->data);
}
return NGX_ERROR;
}本函数用于将名称为src的文件重命名为to的文件，重命名步骤如下：
-
修改src文件访问权限
-
修改src文件的
最近修改时间 -
重命名文件。 此时如果产生
NGX_ENOPATH错误，则创建全路径然后再重命名文件；如果产生NGX_EXDEV错误（Cross-device link)，则先将src文件拷贝到to位置的某个文件，然后再对该文件重命名。
7. 函数ngx_copy_file()
ngx_int_t
ngx_copy_file(u_char *from, u_char *to, ngx_copy_file_t *cf)
{
char *buf;
off_t size;
size_t len;
ssize_t n;
ngx_fd_t fd, nfd;
ngx_int_t rc;
ngx_file_info_t fi;
rc = NGX_ERROR;
buf = NULL;
nfd = NGX_INVALID_FILE;
fd = ngx_open_file(from, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);
if (fd == NGX_INVALID_FILE) {
ngx_log_error(NGX_LOG_CRIT, cf->log, ngx_errno,
ngx_open_file_n " \"%s\" failed", from);
goto failed;
}
if (cf->size != -1) {
size = cf->size;
} else {
if (ngx_fd_info(fd, &fi) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_ALERT, cf->log, ngx_errno,
ngx_fd_info_n " \"%s\" failed", from);
goto failed;
}
size = ngx_file_size(&fi);
}
len = cf->buf_size ? cf->buf_size : 65536;
if ((off_t) len > size) {
len = (size_t) size;
}
buf = ngx_alloc(len, cf->log);
if (buf == NULL) {
goto failed;
}
nfd = ngx_open_file(to, NGX_FILE_WRONLY, NGX_FILE_CREATE_OR_OPEN,
cf->access);
if (nfd == NGX_INVALID_FILE) {
ngx_log_error(NGX_LOG_CRIT, cf->log, ngx_errno,
ngx_open_file_n " \"%s\" failed", to);
goto failed;
}
while (size > 0) {
if ((off_t) len > size) {
len = (size_t) size;
}
n = ngx_read_fd(fd, buf, len);
if (n == -1) {
ngx_log_error(NGX_LOG_ALERT, cf->log, ngx_errno,
ngx_read_fd_n " \"%s\" failed", from);
goto failed;
}
if ((size_t) n != len) {
ngx_log_error(NGX_LOG_ALERT, cf->log, 0,
ngx_read_fd_n " has read only %z of %O from %s",
n, size, from);
goto failed;
}
n = ngx_write_fd(nfd, buf, len);
if (n == -1) {
ngx_log_error(NGX_LOG_ALERT, cf->log, ngx_errno,
ngx_write_fd_n " \"%s\" failed", to);
goto failed;
}
if ((size_t) n != len) {
ngx_log_error(NGX_LOG_ALERT, cf->log, 0,
ngx_write_fd_n " has written only %z of %O to %s",
n, size, to);
goto failed;
}
size -= n;
}
if (cf->time != -1) {
if (ngx_set_file_time(to, nfd, cf->time) != NGX_OK) {
ngx_log_error(NGX_LOG_ALERT, cf->log, ngx_errno,
ngx_set_file_time_n " \"%s\" failed", to);
goto failed;
}
}
rc = NGX_OK;
failed:
if (nfd != NGX_INVALID_FILE) {
if (ngx_close_file(nfd) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_ALERT, cf->log, ngx_errno,
ngx_close_file_n " \"%s\" failed", to);
}
}
if (fd != NGX_INVALID_FILE) {
if (ngx_close_file(fd) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_ALERT, cf->log, ngx_errno,
ngx_close_file_n " \"%s\" failed", from);
}
}
if (buf) {
ngx_free(buf);
}
return rc;
}本函数较为简单，将from文件拷贝为to`文件。在拷贝时由cf指定拷贝大小以及拷贝过程中用的缓冲区大小。
8. 函数ngx_walk_tree()
/*
* ctx->init_handler() - see ctx->alloc
* ctx->file_handler() - file handler
* ctx->pre_tree_handler() - handler is called before entering directory
* ctx->post_tree_handler() - handler is called after leaving directory
* ctx->spec_handler() - special (socket, FIFO, etc.) file handler
*
* ctx->data - some data structure, it may be the same on all levels, or
* reallocated if ctx->alloc is nonzero
*
* ctx->alloc - a size of data structure that is allocated at every level
* and is initialized by ctx->init_handler()
*
* ctx->log - a log
*
* on fatal (memory) error handler must return NGX_ABORT to stop walking tree
*/
ngx_int_t
ngx_walk_tree(ngx_tree_ctx_t *ctx, ngx_str_t *tree)
{
void *data, *prev;
u_char *p, *name;
size_t len;
ngx_int_t rc;
ngx_err_t err;
ngx_str_t file, buf;
ngx_dir_t dir;
ngx_str_null(&buf);
ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
"walk tree \"%V\"", tree);
if (ngx_open_dir(tree, &dir) == NGX_ERROR) {
ngx_log_error(NGX_LOG_CRIT, ctx->log, ngx_errno,
ngx_open_dir_n " \"%s\" failed", tree->data);
return NGX_ERROR;
}
prev = ctx->data;
if (ctx->alloc) {
data = ngx_alloc(ctx->alloc, ctx->log);
if (data == NULL) {
goto failed;
}
if (ctx->init_handler(data, prev) == NGX_ABORT) {
goto failed;
}
ctx->data = data;
} else {
data = NULL;
}
for ( ;; ) {
ngx_set_errno(0);
if (ngx_read_dir(&dir) == NGX_ERROR) {
err = ngx_errno;
if (err == NGX_ENOMOREFILES) {
rc = NGX_OK;
} else {
ngx_log_error(NGX_LOG_CRIT, ctx->log, err,
ngx_read_dir_n " \"%s\" failed", tree->data);
rc = NGX_ERROR;
}
goto done;
}
len = ngx_de_namelen(&dir);
name = ngx_de_name(&dir);
ngx_log_debug2(NGX_LOG_DEBUG_CORE, ctx->log, 0,
"tree name %uz:\"%s\"", len, name);
if (len == 1 && name[0] == '.') {
continue;
}
if (len == 2 && name[0] == '.' && name[1] == '.') {
continue;
}
file.len = tree->len + 1 + len;
if (file.len + NGX_DIR_MASK_LEN > buf.len) {
if (buf.len) {
ngx_free(buf.data);
}
buf.len = tree->len + 1 + len + NGX_DIR_MASK_LEN;
buf.data = ngx_alloc(buf.len + 1, ctx->log);
if (buf.data == NULL) {
goto failed;
}
}
p = ngx_cpymem(buf.data, tree->data, tree->len);
*p++ = '/';
ngx_memcpy(p, name, len + 1);
file.data = buf.data;
ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
"tree path \"%s\"", file.data);
if (!dir.valid_info) {
if (ngx_de_info(file.data, &dir) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_CRIT, ctx->log, ngx_errno,
ngx_de_info_n " \"%s\" failed", file.data);
continue;
}
}
if (ngx_de_is_file(&dir)) {
ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
"tree file \"%s\"", file.data);
ctx->size = ngx_de_size(&dir);
ctx->fs_size = ngx_de_fs_size(&dir);
ctx->access = ngx_de_access(&dir);
ctx->mtime = ngx_de_mtime(&dir);
if (ctx->file_handler(ctx, &file) == NGX_ABORT) {
goto failed;
}
} else if (ngx_de_is_dir(&dir)) {
ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
"tree enter dir \"%s\"", file.data);
ctx->access = ngx_de_access(&dir);
ctx->mtime = ngx_de_mtime(&dir);
rc = ctx->pre_tree_handler(ctx, &file);
if (rc == NGX_ABORT) {
goto failed;
}
if (rc == NGX_DECLINED) {
ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
"tree skip dir \"%s\"", file.data);
continue;
}
if (ngx_walk_tree(ctx, &file) == NGX_ABORT) {
goto failed;
}
ctx->access = ngx_de_access(&dir);
ctx->mtime = ngx_de_mtime(&dir);
if (ctx->post_tree_handler(ctx, &file) == NGX_ABORT) {
goto failed;
}
} else {
ngx_log_debug1(NGX_LOG_DEBUG_CORE, ctx->log, 0,
"tree special \"%s\"", file.data);
if (ctx->spec_handler(ctx, &file) == NGX_ABORT) {
goto failed;
}
}
}
failed:
rc = NGX_ABORT;
done:
if (buf.len) {
ngx_free(buf.data);
}
if (data) {
ngx_free(data);
ctx->data = prev;
}
if (ngx_close_dir(&dir) == NGX_ERROR) {
ngx_log_error(NGX_LOG_CRIT, ctx->log, ngx_errno,
ngx_close_dir_n " \"%s\" failed", tree->data);
}
return rc;
}本函数较为简单，遍历tree目录下的所有文件，这里有3中情况：
-
遍历到的文件时普通文件: 直接调用ctx->file_handler()处理
-
遍历到的文件的目录文件: 递归调用ngx_walk_tree()遍历文件，此时会调用两个回调函数，一个是进入目录时的回调pre_tree_handler()；另一个是离开目录时的回调post_tree_handler()
-
遍历到的文件时特殊文件: 调用ctx->spec_handler()处理
这里注意如果ctx->alloc不为0，则会创建一个空间data,并调用ctx->init_handler(data,ctx->data)来进行相关数据结构初始化。
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