1 #include "cache.h"
2 #include "unix-socket.h"
3
4 #define DEFAULT_UNIX_STREAM_LISTEN_BACKLOG (5)
5
chdir_len(const char * orig,int len)6 static int chdir_len(const char *orig, int len)
7 {
8 char *path = xmemdupz(orig, len);
9 int r = chdir(path);
10 free(path);
11 return r;
12 }
13
14 struct unix_sockaddr_context {
15 char *orig_dir;
16 };
17
unix_sockaddr_cleanup(struct unix_sockaddr_context * ctx)18 static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
19 {
20 if (!ctx->orig_dir)
21 return;
22 /*
23 * If we fail, we can't just return an error, since we have
24 * moved the cwd of the whole process, which could confuse calling
25 * code. We are better off to just die.
26 */
27 if (chdir(ctx->orig_dir) < 0)
28 die("unable to restore original working directory");
29 free(ctx->orig_dir);
30 }
31
unix_sockaddr_init(struct sockaddr_un * sa,const char * path,struct unix_sockaddr_context * ctx,int disallow_chdir)32 static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
33 struct unix_sockaddr_context *ctx,
34 int disallow_chdir)
35 {
36 int size = strlen(path) + 1;
37
38 ctx->orig_dir = NULL;
39 if (size > sizeof(sa->sun_path)) {
40 const char *slash;
41 const char *dir;
42 struct strbuf cwd = STRBUF_INIT;
43
44 if (disallow_chdir) {
45 errno = ENAMETOOLONG;
46 return -1;
47 }
48
49 slash = find_last_dir_sep(path);
50 if (!slash) {
51 errno = ENAMETOOLONG;
52 return -1;
53 }
54
55 dir = path;
56 path = slash + 1;
57 size = strlen(path) + 1;
58 if (size > sizeof(sa->sun_path)) {
59 errno = ENAMETOOLONG;
60 return -1;
61 }
62 if (strbuf_getcwd(&cwd))
63 return -1;
64 ctx->orig_dir = strbuf_detach(&cwd, NULL);
65 if (chdir_len(dir, slash - dir) < 0)
66 return -1;
67 }
68
69 memset(sa, 0, sizeof(*sa));
70 sa->sun_family = AF_UNIX;
71 memcpy(sa->sun_path, path, size);
72 return 0;
73 }
74
unix_stream_connect(const char * path,int disallow_chdir)75 int unix_stream_connect(const char *path, int disallow_chdir)
76 {
77 int fd = -1, saved_errno;
78 struct sockaddr_un sa;
79 struct unix_sockaddr_context ctx;
80
81 if (unix_sockaddr_init(&sa, path, &ctx, disallow_chdir) < 0)
82 return -1;
83 fd = socket(AF_UNIX, SOCK_STREAM, 0);
84 if (fd < 0)
85 goto fail;
86
87 if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
88 goto fail;
89 unix_sockaddr_cleanup(&ctx);
90 return fd;
91
92 fail:
93 saved_errno = errno;
94 if (fd != -1)
95 close(fd);
96 unix_sockaddr_cleanup(&ctx);
97 errno = saved_errno;
98 return -1;
99 }
100
unix_stream_listen(const char * path,const struct unix_stream_listen_opts * opts)101 int unix_stream_listen(const char *path,
102 const struct unix_stream_listen_opts *opts)
103 {
104 int fd = -1, saved_errno;
105 int backlog;
106 struct sockaddr_un sa;
107 struct unix_sockaddr_context ctx;
108
109 unlink(path);
110
111 if (unix_sockaddr_init(&sa, path, &ctx, opts->disallow_chdir) < 0)
112 return -1;
113 fd = socket(AF_UNIX, SOCK_STREAM, 0);
114 if (fd < 0)
115 goto fail;
116
117 if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
118 goto fail;
119
120 backlog = opts->listen_backlog_size;
121 if (backlog <= 0)
122 backlog = DEFAULT_UNIX_STREAM_LISTEN_BACKLOG;
123 if (listen(fd, backlog) < 0)
124 goto fail;
125
126 unix_sockaddr_cleanup(&ctx);
127 return fd;
128
129 fail:
130 saved_errno = errno;
131 if (fd != -1)
132 close(fd);
133 unix_sockaddr_cleanup(&ctx);
134 errno = saved_errno;
135 return -1;
136 }
137