Have start_command() create a pipe to read the stderr of the child.
[git/git.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 need_in = !cmd->no_stdin && cmd->in < 0;
24 if (need_in) {
25 if (pipe(fdin) < 0)
26 return -ERR_RUN_COMMAND_PIPE;
27 cmd->in = fdin[1];
28 cmd->close_in = 1;
29 }
30
31 need_out = !cmd->no_stdout
32 && !cmd->stdout_to_stderr
33 && cmd->out < 0;
34 if (need_out) {
35 if (pipe(fdout) < 0) {
36 if (need_in)
37 close_pair(fdin);
38 return -ERR_RUN_COMMAND_PIPE;
39 }
40 cmd->out = fdout[0];
41 cmd->close_out = 1;
42 }
43
44 need_err = cmd->err < 0;
45 if (need_err) {
46 if (pipe(fderr) < 0) {
47 if (need_in)
48 close_pair(fdin);
49 if (need_out)
50 close_pair(fdout);
51 return -ERR_RUN_COMMAND_PIPE;
52 }
53 cmd->err = fderr[0];
54 }
55
56 cmd->pid = fork();
57 if (cmd->pid < 0) {
58 if (need_in)
59 close_pair(fdin);
60 if (need_out)
61 close_pair(fdout);
62 if (need_err)
63 close_pair(fderr);
64 return -ERR_RUN_COMMAND_FORK;
65 }
66
67 if (!cmd->pid) {
68 if (cmd->no_stdin)
69 dup_devnull(0);
70 else if (need_in) {
71 dup2(fdin[0], 0);
72 close_pair(fdin);
73 } else if (cmd->in) {
74 dup2(cmd->in, 0);
75 close(cmd->in);
76 }
77
78 if (cmd->no_stdout)
79 dup_devnull(1);
80 else if (cmd->stdout_to_stderr)
81 dup2(2, 1);
82 else if (need_out) {
83 dup2(fdout[1], 1);
84 close_pair(fdout);
85 } else if (cmd->out > 1) {
86 dup2(cmd->out, 1);
87 close(cmd->out);
88 }
89
90 if (need_err) {
91 dup2(fderr[1], 2);
92 close_pair(fderr);
93 }
94
95 if (cmd->dir && chdir(cmd->dir))
96 die("exec %s: cd to %s failed (%s)", cmd->argv[0],
97 cmd->dir, strerror(errno));
98 if (cmd->env) {
99 for (; *cmd->env; cmd->env++) {
100 if (strchr(*cmd->env, '='))
101 putenv((char*)*cmd->env);
102 else
103 unsetenv(*cmd->env);
104 }
105 }
106 if (cmd->git_cmd) {
107 execv_git_cmd(cmd->argv);
108 } else {
109 execvp(cmd->argv[0], (char *const*) cmd->argv);
110 }
111 die("exec %s failed.", cmd->argv[0]);
112 }
113
114 if (need_in)
115 close(fdin[0]);
116 else if (cmd->in)
117 close(cmd->in);
118
119 if (need_out)
120 close(fdout[1]);
121 else if (cmd->out > 1)
122 close(cmd->out);
123
124 if (need_err)
125 close(fderr[1]);
126
127 return 0;
128 }
129
130 int finish_command(struct child_process *cmd)
131 {
132 if (cmd->close_in)
133 close(cmd->in);
134 if (cmd->close_out)
135 close(cmd->out);
136
137 for (;;) {
138 int status, code;
139 pid_t waiting = waitpid(cmd->pid, &status, 0);
140
141 if (waiting < 0) {
142 if (errno == EINTR)
143 continue;
144 error("waitpid failed (%s)", strerror(errno));
145 return -ERR_RUN_COMMAND_WAITPID;
146 }
147 if (waiting != cmd->pid)
148 return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
149 if (WIFSIGNALED(status))
150 return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
151
152 if (!WIFEXITED(status))
153 return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
154 code = WEXITSTATUS(status);
155 if (code)
156 return -code;
157 return 0;
158 }
159 }
160
161 int run_command(struct child_process *cmd)
162 {
163 int code = start_command(cmd);
164 if (code)
165 return code;
166 return finish_command(cmd);
167 }
168
169 static void prepare_run_command_v_opt(struct child_process *cmd,
170 const char **argv,
171 int opt)
172 {
173 memset(cmd, 0, sizeof(*cmd));
174 cmd->argv = argv;
175 cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
176 cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
177 cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
178 }
179
180 int run_command_v_opt(const char **argv, int opt)
181 {
182 struct child_process cmd;
183 prepare_run_command_v_opt(&cmd, argv, opt);
184 return run_command(&cmd);
185 }
186
187 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
188 {
189 struct child_process cmd;
190 prepare_run_command_v_opt(&cmd, argv, opt);
191 cmd.dir = dir;
192 return run_command(&cmd);
193 }
194
195 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
196 {
197 struct child_process cmd;
198 prepare_run_command_v_opt(&cmd, argv, opt);
199 cmd.dir = dir;
200 cmd.env = env;
201 return run_command(&cmd);
202 }