git ssb

1
#include <stddef.h>
2
#include <unistd.h>
3
#include <stdio.h>
4
#include <stdlib.h>
5
#include <err.h>
6
#include <sys/wait.h>
7
#include <sys/inotify.h>
8
#include <dlfcn.h>
9
#include <pthread.h>
10
11
#include "ccdl.h"
12
13
static const char *my_mktemp()
14
{
15
	const char *tmpdir = getenv("TMPDIR");
16
	if (!tmpdir) tmpdir = "/tmp";
17
	static char buf[256];
18
	ssize_t len = snprintf(buf, sizeof(buf), "%s/ccdl-XXXXXX", tmpdir);
19
	if (len < 0) return NULL;
20
	if (mkstemp(buf) < 0) return NULL;
21
	return buf;
22
}
23
24
void lib_init(struct lib *lib, const char *src_fname, const char *sym_name)
25
{
26
	lib->src_fname = src_fname;
27
	lib->sym_name = sym_name;
28
	lib->handle = NULL;
29
	lib->sym = NULL;
30
}
31
32
static int compile(const char *src, const char *lib)
33
{
34
	if (!src || !lib) return -1;
35
	int child = fork();
36
	if (child < 0) return -1;
37
	if (child == 0) {
38
		char *cc = getenv("CC");
39
		if (!cc) cc = "cc";
40
		char *const argv[] = {
41
			cc, (char *)src, "-o", (char *)lib,
42
			"-fPIC", "-shared", "-lm",
43
			NULL};
44
		if (execvp(argv[0], argv)) err(1, "execvp");
45
		exit(0);
46
	} else {
47
		int wstatus;
48
		if (waitpid(child, &wstatus, 0) < 0) {
49
			return -1;
50
		} else if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) {
51
			return 0;
52
		} else {
53
			return -1;
54
		}
55
	}
56
}
57
58
int lib_build(struct lib *lib)
59
{
60
	void *handle = lib->handle;
61
	if (!handle) {
62
		const char *src_fname = lib->src_fname;
63
		if (!src_fname) return -1;
64
		const char *lib_fname = my_mktemp();
65
		if (!lib_fname) {
66
			warn("mktemp");
67
			return -1;
68
		}
69
		if (compile(src_fname, lib_fname)) return -1;
70
		dlerror();
71
		handle = dlopen(lib_fname, RTLD_NOW);
72
		char *err = dlerror();
73
		if (unlink(lib_fname) < 0) warn("unlink");
74
		if (err) {
75
			warnx("dlopen: %s", err);
76
			return -1;
77
		}
78
		lib->handle = handle;
79
	}
80
	const char *sym_name = lib->sym_name;
81
	if (!sym_name) return -1;
82
	void *sym = dlsym(handle, sym_name);
83
	if (!sym) return -1;
84
	lib->sym = sym;
85
	return 0;
86
}
87
88
void *lib_get(struct lib *lib)
89
{
90
	if (!lib->sym) lib_build(lib);
91
	return lib->sym;
92
}
93
94
void lib_deinit(struct lib *lib)
95
{
96
	if (lib->handle) {
97
		dlclose(lib->handle);
98
		lib->handle = NULL;
99
		lib->sym = NULL;
100
	}
101
}
102
103
void ccdl_init(struct ccdl *ccdl, const char *src_fname, const char *sym_name)
104
{
105
	lib_init(&ccdl->libs[0], src_fname, sym_name);
106
	lib_init(&ccdl->libs[1], src_fname, sym_name);
107
	ccdl->lib = &ccdl->libs[0];
108
}
109
110
static struct lib *ccdl_get_old_lib(struct ccdl *ccdl)
111
{
112
	return ccdl->lib == &ccdl->libs[1] ? &ccdl->libs[0] : &ccdl->libs[1];
113
}
114
115
void *ccdl_get(struct ccdl *ccdl)
116
{
117
	struct lib *old_lib = ccdl_get_old_lib(ccdl);
118
	if (old_lib) {
119
		lib_deinit(old_lib);
120
	}
121
	return lib_get(ccdl->lib);
122
}
123
124
static int ccdl_watch_run(struct ccdl *ccdl)
125
{
126
	int ifd = inotify_init();
127
	int wd = 0;
128
	if (ifd < 0) {
129
		warn("inotify_init");
130
		return -1;
131
	}
132
	if (!ccdl || !ccdl->lib || !ccdl->lib->src_fname) {
133
		warn("missing lib filename");
134
		return -1;
135
	}
136
	wd = inotify_add_watch(ifd, ccdl->lib->src_fname, IN_MODIFY);
137
	if (wd < 0) {
138
		warn("watch");
139
		return -1;
140
	}
141
142
	while (1) {
143
		struct inotify_event ev;
144
		ssize_t len = read(ifd, &ev, sizeof ev);
145
		//printf("readed %zd %u %u %u\n", len, sizeof ev, ev.len, ev.mask);
146
		if (len < 0) {
147
			warn("read");
148
			return -1;
149
		}
150
		if ((size_t)len < sizeof ev) {
151
			warn("small read");
152
			continue;
153
		}
154
		if (ev.len > 0) {
155
			warn("unexpected name");
156
			return -1;
157
		}
158
		if (ev.mask & IN_MODIFY) {
159
		} else if (ev.mask & IN_DELETE_SELF) {
160
			printf("deleted\n");
161
		} else if (ev.mask & IN_IGNORED) {
162
			printf("ignored\n");
163
			// file is being replaced. replace the watch
164
			wd = inotify_add_watch(ifd, ccdl->lib->src_fname, IN_MODIFY);
165
			if (wd < 0) {
166
				warn("inotify_add_watch");
167
				return -1;
168
			}
169
		} else {
170
			printf("unknown mask: %u\n", ev.mask);
171
		}
172
		(void)ccdl_rebuild(ccdl);
173
	}
174
175
	return 0;
176
}
177
178
static void *ccdl_watch_run_thread(void *ccdl)
179
{
180
	return (void *)(intptr_t)ccdl_watch_run(ccdl);
181
}
182
183
int ccdl_watch(struct ccdl *ccdl)
184
{
185
	pthread_t *id = &ccdl->watcher_thread;
186
	if (pthread_create(id, NULL, ccdl_watch_run_thread, ccdl)) return -1;
187
	return 0;
188
}
189
190
int ccdl_rebuild(struct ccdl *ccdl)
191
{
192
	struct lib *new_lib = ccdl_get_old_lib(ccdl);
193
	lib_deinit(new_lib);
194
	if (lib_build(new_lib) < 0) return -1;
195
	ccdl->lib = new_lib;
196
	return 0;
197
}
198
199
int ccdl_deinit(struct ccdl *ccdl)
200
{
201
	pthread_t thread = ccdl->watcher_thread;
202
	if (thread) {
203
		void *retval;
204
		pthread_join(thread, &retval);
205
		return (int)retval;
206
	}
207
	return 0;
208
}
209
210