masqmail
view src/peopen.c @ 281:ea5f86e0a81c
modes are now enforced exclusive
Other MTAs (exim, postfix) are more relaxing, but as combinations
of exclusive modes are senseless we behave more obvious if we
fail early. This makes understanding the behavior easier too.
| author | markus schnalke <meillo@marmaro.de> |
|---|---|
| date | Tue, 07 Dec 2010 14:04:56 -0300 |
| parents | 7cdd30429cc9 |
| children | b27f66555ba8 |
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 */
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>
14 #include "peopen.h"
15 #include "masqmail.h"
17 static void
18 destroy_argv(char **arr)
19 {
20 char *p = arr[0];
21 int i = 0;
23 while (p) {
24 free(p);
25 p = arr[i++];
26 }
27 free(arr);
28 }
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;
38 arr = (char **) g_malloc(sizeof(char *) * count);
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;
54 return arr;
55 }
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;
64 if (command == NULL || type == NULL) {
65 errno = EINVAL;
66 return NULL;
67 }
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;
78 if (pipe(pipe_fd) == -1)
79 return NULL;
81 switch (pid = fork()) {
82 case 0: /* child thread */
84 {
85 int i, max_fd = sysconf(_SC_OPEN_MAX);
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;
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 }
118 _exit(errno);
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);
125 case -1:
126 close(pipe_fd[0]);
127 close(pipe_fd[1]);
128 return NULL;
129 }
130 }
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 }