1#include <unistd.h>
2#include <sys/types.h>
3#include <sys/stat.h>
4#include <fcntl.h>
5#include <string.h>
6#include <errno.h>
7#include <sys/wait.h>
8#include "subcmd-util.h"
9#include "run-command.h"
10#include "exec-cmd.h"
11
12#define STRERR_BUFSIZE 128
13
14static inline void close_pair(int fd[2])
15{
16 close(fd[0]);
17 close(fd[1]);
18}
19
20static inline void dup_devnull(int to)
21{
22 int fd = open("/dev/null", O_RDWR);
23 dup2(fd, to);
24 close(fd);
25}
26
27int start_command(struct child_process *cmd)
28{
29 int need_in, need_out, need_err;
30 int fdin[2], fdout[2], fderr[2];
31 char sbuf[STRERR_BUFSIZE];
32
33
34
35
36
37
38 need_in = !cmd->no_stdin && cmd->in < 0;
39 if (need_in) {
40 if (pipe(fdin) < 0) {
41 if (cmd->out > 0)
42 close(cmd->out);
43 return -ERR_RUN_COMMAND_PIPE;
44 }
45 cmd->in = fdin[1];
46 }
47
48 need_out = !cmd->no_stdout
49 && !cmd->stdout_to_stderr
50 && cmd->out < 0;
51 if (need_out) {
52 if (pipe(fdout) < 0) {
53 if (need_in)
54 close_pair(fdin);
55 else if (cmd->in)
56 close(cmd->in);
57 return -ERR_RUN_COMMAND_PIPE;
58 }
59 cmd->out = fdout[0];
60 }
61
62 need_err = !cmd->no_stderr && cmd->err < 0;
63 if (need_err) {
64 if (pipe(fderr) < 0) {
65 if (need_in)
66 close_pair(fdin);
67 else if (cmd->in)
68 close(cmd->in);
69 if (need_out)
70 close_pair(fdout);
71 else if (cmd->out)
72 close(cmd->out);
73 return -ERR_RUN_COMMAND_PIPE;
74 }
75 cmd->err = fderr[0];
76 }
77
78 fflush(NULL);
79 cmd->pid = fork();
80 if (!cmd->pid) {
81 if (cmd->no_stdin)
82 dup_devnull(0);
83 else if (need_in) {
84 dup2(fdin[0], 0);
85 close_pair(fdin);
86 } else if (cmd->in) {
87 dup2(cmd->in, 0);
88 close(cmd->in);
89 }
90
91 if (cmd->no_stderr)
92 dup_devnull(2);
93 else if (need_err) {
94 dup2(fderr[1], 2);
95 close_pair(fderr);
96 }
97
98 if (cmd->no_stdout)
99 dup_devnull(1);
100 else if (cmd->stdout_to_stderr)
101 dup2(2, 1);
102 else if (need_out) {
103 dup2(fdout[1], 1);
104 close_pair(fdout);
105 } else if (cmd->out > 1) {
106 dup2(cmd->out, 1);
107 close(cmd->out);
108 }
109
110 if (cmd->dir && chdir(cmd->dir))
111 die("exec %s: cd to %s failed (%s)", cmd->argv[0],
112 cmd->dir, strerror_r(errno, sbuf, sizeof(sbuf)));
113 if (cmd->env) {
114 for (; *cmd->env; cmd->env++) {
115 if (strchr(*cmd->env, '='))
116 putenv((char*)*cmd->env);
117 else
118 unsetenv(*cmd->env);
119 }
120 }
121 if (cmd->preexec_cb)
122 cmd->preexec_cb();
123 if (cmd->exec_cmd) {
124 execv_cmd(cmd->argv);
125 } else {
126 execvp(cmd->argv[0], (char *const*) cmd->argv);
127 }
128 exit(127);
129 }
130
131 if (cmd->pid < 0) {
132 int err = errno;
133 if (need_in)
134 close_pair(fdin);
135 else if (cmd->in)
136 close(cmd->in);
137 if (need_out)
138 close_pair(fdout);
139 else if (cmd->out)
140 close(cmd->out);
141 if (need_err)
142 close_pair(fderr);
143 return err == ENOENT ?
144 -ERR_RUN_COMMAND_EXEC :
145 -ERR_RUN_COMMAND_FORK;
146 }
147
148 if (need_in)
149 close(fdin[0]);
150 else if (cmd->in)
151 close(cmd->in);
152
153 if (need_out)
154 close(fdout[1]);
155 else if (cmd->out)
156 close(cmd->out);
157
158 if (need_err)
159 close(fderr[1]);
160
161 return 0;
162}
163
164static int wait_or_whine(pid_t pid)
165{
166 char sbuf[STRERR_BUFSIZE];
167
168 for (;;) {
169 int status, code;
170 pid_t waiting = waitpid(pid, &status, 0);
171
172 if (waiting < 0) {
173 if (errno == EINTR)
174 continue;
175 fprintf(stderr, " Error: waitpid failed (%s)",
176 strerror_r(errno, sbuf, sizeof(sbuf)));
177 return -ERR_RUN_COMMAND_WAITPID;
178 }
179 if (waiting != pid)
180 return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
181 if (WIFSIGNALED(status))
182 return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
183
184 if (!WIFEXITED(status))
185 return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
186 code = WEXITSTATUS(status);
187 switch (code) {
188 case 127:
189 return -ERR_RUN_COMMAND_EXEC;
190 case 0:
191 return 0;
192 default:
193 return -code;
194 }
195 }
196}
197
198int finish_command(struct child_process *cmd)
199{
200 return wait_or_whine(cmd->pid);
201}
202
203int run_command(struct child_process *cmd)
204{
205 int code = start_command(cmd);
206 if (code)
207 return code;
208 return finish_command(cmd);
209}
210
211static void prepare_run_command_v_opt(struct child_process *cmd,
212 const char **argv,
213 int opt)
214{
215 memset(cmd, 0, sizeof(*cmd));
216 cmd->argv = argv;
217 cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
218 cmd->exec_cmd = opt & RUN_EXEC_CMD ? 1 : 0;
219 cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
220}
221
222int run_command_v_opt(const char **argv, int opt)
223{
224 struct child_process cmd;
225 prepare_run_command_v_opt(&cmd, argv, opt);
226 return run_command(&cmd);
227}
228
