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hush: explain parsing context structure

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plug leak in setup_redirect on error path

function                                             old     new   delta
done_command                                          84      86      +2
done_word                                            657     658      +1
done_pipe                                            105     106      +1
initialize_context                                    39      38      -1
setup_redirect                                       219     212      -7
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/2 up/down: 4/-8)               Total: -4 bytes
This commit is contained in:
Denis Vlasenko 2009-04-03 00:07:05 +00:00
parent 027e3fddb5
commit f9f7429346
1 changed files with 32 additions and 21 deletions
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53
shell/hush.c
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@ -359,9 +359,13 @@ struct pipe {
/* This holds pointers to the various results of parsing */ /* This holds pointers to the various results of parsing */
struct parse_context { struct parse_context {
struct command *command; /* linked list of pipes */
struct pipe *list_head; struct pipe *list_head;
/* last pipe (being constructed right now) */
struct pipe *pipe; struct pipe *pipe;
/* last command in pipe (being constructed right now) */
struct command *command;
/* last redirect in command->redirects list */
struct redir_struct *pending_redirect; struct redir_struct *pending_redirect;
#if HAS_KEYWORDS #if HAS_KEYWORDS
smallint ctx_res_w; smallint ctx_res_w;
@ -369,7 +373,15 @@ struct parse_context {
#if ENABLE_HUSH_CASE #if ENABLE_HUSH_CASE
smallint ctx_dsemicolon; /* ";;" seen */ smallint ctx_dsemicolon; /* ";;" seen */
#endif #endif
int old_flag; /* bitmask of FLAG_xxx, for figuring out valid reserved words */ /* bitmask of FLAG_xxx, for figuring out valid reserved words */
int old_flag;
/* group we are enclosed in:
* example 1: "{ { false; ..."
* example 2: "if true; then { false; ..."
* example 3: "if true; then if false; ..."
* when we find closing "}" / "fi" / whatever, we move list_head
* into stack->command->group and delete ourself.
*/
struct parse_context *stack; struct parse_context *stack;
#endif #endif
}; };
@ -3288,37 +3300,36 @@ static int redirect_dup_num(struct in_str *input)
* for file descriptor duplication, e.g., "2>&1". * for file descriptor duplication, e.g., "2>&1".
* Return code is 0 normally, 1 if a syntax error is detected in src. * Return code is 0 normally, 1 if a syntax error is detected in src.
* Resource errors (in xmalloc) cause the process to exit */ * Resource errors (in xmalloc) cause the process to exit */
static int setup_redirect(struct parse_context *ctx, int fd, redir_type style, static int setup_redirect(struct parse_context *ctx,
struct in_str *input) int fd,
redir_type style,
struct in_str *input)
{ {
struct command *command = ctx->command; struct command *command = ctx->command;
struct redir_struct *redir = command->redirects; struct redir_struct *redir;
struct redir_struct *last_redir = NULL; struct redir_struct **redirp;
int dup_num;
/* Check for a '2>&1' type redirect */
dup_num = redirect_dup_num(input);
if (dup_num == -2)
return 1; /* syntax error */
/* Create a new redir_struct and drop it onto the end of the linked list */ /* Create a new redir_struct and drop it onto the end of the linked list */
while (redir) { redirp = &command->redirects;
last_redir = redir; while ((redir = *redirp) != NULL) {
redir = redir->next; redirp = &(redir->next);
} }
redir = xzalloc(sizeof(struct redir_struct)); *redirp = redir = xzalloc(sizeof(*redir));
/* redir->next = NULL; */ /* redir->next = NULL; */
/* redir->rd_filename = NULL; */ /* redir->rd_filename = NULL; */
if (last_redir) {
last_redir->next = redir;
} else {
command->redirects = redir;
}
redir->rd_type = style; redir->rd_type = style;
redir->fd = (fd == -1) ? redir_table[style].default_fd : fd; redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip); debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
/* Check for a '2>&1' type redirect */ redir->dup = dup_num;
redir->dup = redirect_dup_num(input); if (dup_num != -1) {
if (redir->dup == -2)
return 1; /* syntax error */
if (redir->dup != -1) {
/* Erik had a check here that the file descriptor in question /* Erik had a check here that the file descriptor in question
* is legit; I postpone that to "run time" * is legit; I postpone that to "run time"
* A "-" representation of "close me" shows up as a -3 here */ * A "-" representation of "close me" shows up as a -3 here */