masqmail

view src/peopen.c @ 221:8742d2cee364

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added a note to the long vs. int question in md5.h Solar Designer explained to me in privat conversation that the int had performed much better on some systems and that 16bit ints are very rare. Still I like using the long.
author meillo@marmaro.de
date Fri, 23 Jul 2010 10:53:04 +0200
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 */
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 }