allow git-am to run in a subdirectory
[git] / run-command.c
1 #include "cache.h"
2 #include "run-command.h"
3 #include "exec_cmd.h"
4
5 static inline void close_pair(int fd[2])
6 {
7         close(fd[0]);
8         close(fd[1]);
9 }
10
11 static inline void dup_devnull(int to)
12 {
13         int fd = open("/dev/null", O_RDWR);
14         dup2(fd, to);
15         close(fd);
16 }
17
18 int start_command(struct child_process *cmd)
19 {
20         int need_in, need_out, need_err;
21         int fdin[2], fdout[2], fderr[2];
22
23         /*
24          * In case of errors we must keep the promise to close FDs
25          * that have been passed in via ->in and ->out.
26          */
27
28         need_in = !cmd->no_stdin && cmd->in < 0;
29         if (need_in) {
30                 if (pipe(fdin) < 0) {
31                         if (cmd->out > 0)
32                                 close(cmd->out);
33                         return -ERR_RUN_COMMAND_PIPE;
34                 }
35                 cmd->in = fdin[1];
36         }
37
38         need_out = !cmd->no_stdout
39                 && !cmd->stdout_to_stderr
40                 && cmd->out < 0;
41         if (need_out) {
42                 if (pipe(fdout) < 0) {
43                         if (need_in)
44                                 close_pair(fdin);
45                         else if (cmd->in)
46                                 close(cmd->in);
47                         return -ERR_RUN_COMMAND_PIPE;
48                 }
49                 cmd->out = fdout[0];
50         }
51
52         need_err = !cmd->no_stderr && cmd->err < 0;
53         if (need_err) {
54                 if (pipe(fderr) < 0) {
55                         if (need_in)
56                                 close_pair(fdin);
57                         else if (cmd->in)
58                                 close(cmd->in);
59                         if (need_out)
60                                 close_pair(fdout);
61                         else if (cmd->out)
62                                 close(cmd->out);
63                         return -ERR_RUN_COMMAND_PIPE;
64                 }
65                 cmd->err = fderr[0];
66         }
67
68         cmd->pid = fork();
69         if (cmd->pid < 0) {
70                 if (need_in)
71                         close_pair(fdin);
72                 else if (cmd->in)
73                         close(cmd->in);
74                 if (need_out)
75                         close_pair(fdout);
76                 else if (cmd->out)
77                         close(cmd->out);
78                 if (need_err)
79                         close_pair(fderr);
80                 return -ERR_RUN_COMMAND_FORK;
81         }
82
83         if (!cmd->pid) {
84                 if (cmd->no_stdin)
85                         dup_devnull(0);
86                 else if (need_in) {
87                         dup2(fdin[0], 0);
88                         close_pair(fdin);
89                 } else if (cmd->in) {
90                         dup2(cmd->in, 0);
91                         close(cmd->in);
92                 }
93
94                 if (cmd->no_stdout)
95                         dup_devnull(1);
96                 else if (cmd->stdout_to_stderr)
97                         dup2(2, 1);
98                 else if (need_out) {
99                         dup2(fdout[1], 1);
100                         close_pair(fdout);
101                 } else if (cmd->out > 1) {
102                         dup2(cmd->out, 1);
103                         close(cmd->out);
104                 }
105
106                 if (cmd->no_stderr)
107                         dup_devnull(2);
108                 else if (need_err) {
109                         dup2(fderr[1], 2);
110                         close_pair(fderr);
111                 }
112
113                 if (cmd->dir && chdir(cmd->dir))
114                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
115                             cmd->dir, strerror(errno));
116                 if (cmd->env) {
117                         for (; *cmd->env; cmd->env++) {
118                                 if (strchr(*cmd->env, '='))
119                                         putenv((char*)*cmd->env);
120                                 else
121                                         unsetenv(*cmd->env);
122                         }
123                 }
124                 if (cmd->git_cmd) {
125                         execv_git_cmd(cmd->argv);
126                 } else {
127                         execvp(cmd->argv[0], (char *const*) cmd->argv);
128                 }
129                 die("exec %s failed.", cmd->argv[0]);
130         }
131
132         if (need_in)
133                 close(fdin[0]);
134         else if (cmd->in)
135                 close(cmd->in);
136
137         if (need_out)
138                 close(fdout[1]);
139         else if (cmd->out)
140                 close(cmd->out);
141
142         if (need_err)
143                 close(fderr[1]);
144
145         return 0;
146 }
147
148 static int wait_or_whine(pid_t pid)
149 {
150         for (;;) {
151                 int status, code;
152                 pid_t waiting = waitpid(pid, &status, 0);
153
154                 if (waiting < 0) {
155                         if (errno == EINTR)
156                                 continue;
157                         error("waitpid failed (%s)", strerror(errno));
158                         return -ERR_RUN_COMMAND_WAITPID;
159                 }
160                 if (waiting != pid)
161                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
162                 if (WIFSIGNALED(status))
163                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
164
165                 if (!WIFEXITED(status))
166                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
167                 code = WEXITSTATUS(status);
168                 if (code)
169                         return -code;
170                 return 0;
171         }
172 }
173
174 int finish_command(struct child_process *cmd)
175 {
176         return wait_or_whine(cmd->pid);
177 }
178
179 int run_command(struct child_process *cmd)
180 {
181         int code = start_command(cmd);
182         if (code)
183                 return code;
184         return finish_command(cmd);
185 }
186
187 static void prepare_run_command_v_opt(struct child_process *cmd,
188                                       const char **argv,
189                                       int opt)
190 {
191         memset(cmd, 0, sizeof(*cmd));
192         cmd->argv = argv;
193         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
194         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
195         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
196 }
197
198 int run_command_v_opt(const char **argv, int opt)
199 {
200         struct child_process cmd;
201         prepare_run_command_v_opt(&cmd, argv, opt);
202         return run_command(&cmd);
203 }
204
205 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
206 {
207         struct child_process cmd;
208         prepare_run_command_v_opt(&cmd, argv, opt);
209         cmd.dir = dir;
210         return run_command(&cmd);
211 }
212
213 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
214 {
215         struct child_process cmd;
216         prepare_run_command_v_opt(&cmd, argv, opt);
217         cmd.dir = dir;
218         cmd.env = env;
219         return run_command(&cmd);
220 }
221
222 int start_async(struct async *async)
223 {
224         int pipe_out[2];
225
226         if (pipe(pipe_out) < 0)
227                 return error("cannot create pipe: %s", strerror(errno));
228
229         async->pid = fork();
230         if (async->pid < 0) {
231                 error("fork (async) failed: %s", strerror(errno));
232                 close_pair(pipe_out);
233                 return -1;
234         }
235         if (!async->pid) {
236                 close(pipe_out[0]);
237                 exit(!!async->proc(pipe_out[1], async->data));
238         }
239         async->out = pipe_out[0];
240         close(pipe_out[1]);
241         return 0;
242 }
243
244 int finish_async(struct async *async)
245 {
246         int ret = 0;
247
248         if (wait_or_whine(async->pid))
249                 ret = error("waitpid (async) failed");
250         return ret;
251 }