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-rw-r--r--filter.c81
1 files changed, 60 insertions, 21 deletions
diff --git a/filter.c b/filter.c
index 30bc74b..f5a5992 100644
--- a/filter.c
+++ b/filter.c
@@ -12,6 +12,11 @@
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
+#include <dlfcn.h>
+
+static ssize_t (*libc_write)(int fd, const void *buf, size_t count);
+static ssize_t (*filter_write)(struct cgit_filter *base, const void *buf, size_t count) = NULL;
+static struct cgit_filter *current_write_filter = NULL;
static inline void reap_filter(struct cgit_filter *filter)
{
@@ -32,12 +37,43 @@ void cgit_cleanup_filters(void)
}
}
+void cgit_init_filters(void)
+{
+ libc_write = dlsym(RTLD_NEXT, "write");
+ if (!libc_write)
+ die("Could not locate libc's write function");
+}
+
+ssize_t write(int fd, const void *buf, size_t count)
+{
+ if (fd != STDOUT_FILENO || !filter_write)
+ return libc_write(fd, buf, count);
+ return filter_write(current_write_filter, buf, count);
+}
+
+static inline void hook_write(struct cgit_filter *filter, ssize_t (*new_write)(struct cgit_filter *base, const void *buf, size_t count))
+{
+ /* We want to avoid buggy nested patterns. */
+ assert(filter_write == NULL);
+ assert(current_write_filter == NULL);
+ current_write_filter = filter;
+ filter_write = new_write;
+}
+
+static inline void unhook_write()
+{
+ assert(filter_write != NULL);
+ assert(current_write_filter != NULL);
+ filter_write = NULL;
+ current_write_filter = NULL;
+}
+
static int open_exec_filter(struct cgit_filter *base, va_list ap)
{
struct cgit_exec_filter *filter = (struct cgit_exec_filter *) base;
int i;
- for (i = 0; i < filter->extra_args; i++)
+ for (i = 0; i < filter->base.argument_count; i++)
filter->argv[i+1] = va_arg(ap, char *);
filter->old_stdout = chk_positive(dup(STDOUT_FILENO),
@@ -74,7 +110,7 @@ static int close_exec_filter(struct cgit_filter *base)
die("Subprocess %s exited abnormally", filter->cmd);
done:
- for (i = 0; i < filter->extra_args; i++)
+ for (i = 0; i < filter->base.argument_count; i++)
filter->argv[i+1] = NULL;
return 0;
@@ -99,7 +135,7 @@ static void cleanup_exec_filter(struct cgit_filter *base)
}
}
-static struct cgit_filter *new_exec_filter(const char *cmd, filter_type filtertype)
+static struct cgit_filter *new_exec_filter(const char *cmd, int argument_count)
{
struct cgit_exec_filter *f;
int args_size = 0;
@@ -107,20 +143,8 @@ static struct cgit_filter *new_exec_filter(const char *cmd, filter_type filterty
f = xmalloc(sizeof(*f));
/* We leave argv for now and assign it below. */
cgit_exec_filter_init(f, xstrdup(cmd), NULL);
-
- switch (filtertype) {
- case SOURCE:
- case ABOUT:
- f->extra_args = 1;
- break;
-
- case COMMIT:
- default:
- f->extra_args = 0;
- break;
- }
-
- args_size = (2 + f->extra_args) * sizeof(char *);
+ f->base.argument_count = argument_count;
+ args_size = (2 + argument_count) * sizeof(char *);
f->argv = xmalloc(args_size);
memset(f->argv, 0, args_size);
f->argv[0] = f->cmd;
@@ -136,6 +160,8 @@ void cgit_exec_filter_init(struct cgit_exec_filter *filter, char *cmd, char **ar
filter->base.cleanup = cleanup_exec_filter;
filter->cmd = cmd;
filter->argv = argv;
+ /* The argument count for open_filter is zero by default, unless called from new_filter, above. */
+ filter->base.argument_count = 0;
}
int cgit_open_filter(struct cgit_filter *filter, ...)
@@ -162,7 +188,7 @@ void cgit_fprintf_filter(struct cgit_filter *filter, FILE *f, const char *prefix
static const struct {
const char *prefix;
- struct cgit_filter *(*ctor)(const char *cmd, filter_type filtertype);
+ struct cgit_filter *(*ctor)(const char *cmd, int argument_count);
} filter_specs[] = {
{ "exec", new_exec_filter },
};
@@ -172,6 +198,8 @@ struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype)
char *colon;
int i;
size_t len;
+ int argument_count;
+
if (!cmd || !cmd[0])
return NULL;
@@ -184,16 +212,27 @@ struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype)
if (len == 1)
colon = NULL;
+ switch (filtertype) {
+ case SOURCE:
+ case ABOUT:
+ argument_count = 1;
+ break;
+
+ case COMMIT:
+ default:
+ argument_count = 0;
+ break;
+ }
+
/* If no prefix is given, exec filter is the default. */
if (!colon)
- return new_exec_filter(cmd, filtertype);
+ return new_exec_filter(cmd, argument_count);
for (i = 0; i < ARRAY_SIZE(filter_specs); i++) {
if (len == strlen(filter_specs[i].prefix) &&
!strncmp(filter_specs[i].prefix, cmd, len))
- return filter_specs[i].ctor(colon + 1, filtertype);
+ return filter_specs[i].ctor(colon + 1, argument_count);
}
die("Invalid filter type: %.*s", (int) len, cmd);
}
-