masqmail

view src/peopen.c @ 156:ee2afbf92428

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require host_name to be set in config file exit otherwise there is no portable way to determine the hostname (actually the hostname that masqmail should use) thus it must be set by the administrator
author meillo@marmaro.de
date Thu, 08 Jul 2010 09:49:05 +0200
parents 3654c502a4df
children dcb315792513
line source
1 /* This a snippet I found in sourceforge. I just changed the identing
2 style to my own and deleted the main function. -- oku
3 The functions destroy_argv() and create_argv() were added by oku.
4 */
5
6 #include <errno.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <unistd.h>
10 #include <string.h>
11 #include <sys/types.h>
12 #include <sysexits.h>
13
14 #include "peopen.h"
15 #include "masqmail.h"
16
17 static void
18 destroy_argv(char **arr)
19 {
20 char *p = arr[0];
21 int i = 0;
22
23 while (p) {
24 free(p);
25 p = arr[i++];
26 }
27 free(arr);
28 }
29
30 static char**
31 create_argv(const char *cmd, int count)
32 {
33 char buf[strlen(cmd) + 1];
34 char **arr, *q;
35 const char *p;
36 int i = 0;
37
38 arr = (char **) g_malloc(sizeof(char *) * count);
39
40 p = cmd;
41 while (*p && i < (count - 1)) {
42 while (*p && isspace(*p))
43 p++;
44 q = buf;
45 while (*p && !isspace(*p))
46 *q++ = *p++;
47 *q = '\0';
48 arr[i++] = strdup(buf);
49 while (*p && isspace(*p))
50 p++;
51 }
52 arr[i] = NULL;
53
54 return arr;
55 }
56
57 FILE*
58 peidopen(const char *command, const char *type, char *const envp[], int *ret_pid, uid_t uid, gid_t gid)
59 {
60 enum { Read, Write } mode;
61 int pipe_fd[2];
62 pid_t pid;
63
64 if (command == NULL || type == NULL) {
65 errno = EINVAL;
66 return NULL;
67 }
68
69 if (strcmp(type, "r")) {
70 if (strcmp(type, "w")) {
71 errno = EINVAL;
72 return NULL;
73 } else
74 mode = Write;
75 } else
76 mode = Read;
77
78 if (pipe(pipe_fd) == -1)
79 return NULL;
80
81 switch (pid = fork()) {
82 case 0: /* child thread */
83
84 {
85 int i, max_fd = sysconf(_SC_OPEN_MAX);
86
87 if (max_fd <= 0)
88 max_fd = 64;
89 for (i = 0; i < max_fd; i++)
90 if ((i != pipe_fd[0]) && (i != pipe_fd[1]))
91 close(i);
92 }
93 if (close(pipe_fd[mode == Read ? 0 : 1]) != -1 &&
94 dup2(pipe_fd[mode == Read ? 1 : 0],
95 mode == Read ? STDOUT_FILENO : STDIN_FILENO) != -1) {
96 // char *argv [] = { "/bin/sh", "-c", (char*) command, NULL };
97 char **argv = create_argv(command, 10);
98 int ret;
99
100 if (uid != (uid_t) - 1) {
101 if ((ret = seteuid(0)) != 0) {
102 exit(EX_NOPERM);
103 }
104 }
105 if (gid != (gid_t) - 1) {
106 if ((ret = setgid(gid)) != 0) {
107 exit(EX_NOPERM);
108 }
109 }
110 if (uid != (uid_t) - 1) {
111 if ((ret = setuid(uid)) != 0) {
112 exit(EX_NOPERM);
113 }
114 }
115 execve(*argv, argv, envp);
116 }
117
118 _exit(errno);
119
120 default: /* parent thread */
121 *ret_pid = pid;
122 close(pipe_fd[mode == Read ? 1 : 0]);
123 return fdopen(pipe_fd[mode == Read ? 0 : 1], type);
124
125 case -1:
126 close(pipe_fd[0]);
127 close(pipe_fd[1]);
128 return NULL;
129 }
130 }
131
132 FILE*
133 peopen(const char *command, const char *type, char *const envp[], int *ret_pid)
134 {
135 return peidopen(command, type, envp, ret_pid, -1, -1);
136 }