| 1 | /* getgrent(), getgrgid(), getgrnam() - group file routines
|
|---|
| 2 | *
|
|---|
| 3 | * Author: Kees J. Bot
|
|---|
| 4 | * 31 Jan 1994
|
|---|
| 5 | */
|
|---|
| 6 | #define nil 0
|
|---|
| 7 | #define open _open
|
|---|
| 8 | #define fcntl _fcntl
|
|---|
| 9 | #define read _read
|
|---|
| 10 | #define close _close
|
|---|
| 11 | #include <sys/types.h>
|
|---|
| 12 | #include <grp.h>
|
|---|
| 13 | #include <string.h>
|
|---|
| 14 | #include <stdlib.h>
|
|---|
| 15 | #include <unistd.h>
|
|---|
| 16 | #include <fcntl.h>
|
|---|
| 17 |
|
|---|
| 18 | #define arraysize(a) (sizeof(a) / sizeof((a)[0]))
|
|---|
| 19 | #define arraylimit(a) ((a) + arraysize(a))
|
|---|
| 20 |
|
|---|
| 21 | static char GROUP[]= "/etc/group"; /* The group file. */
|
|---|
| 22 | static const char *grfile; /* Current group file. */
|
|---|
| 23 |
|
|---|
| 24 | static char buf[1024]; /* Read buffer. */
|
|---|
| 25 | static char grline[512]; /* One line from the group file. */
|
|---|
| 26 | static struct group entry; /* Entry to fill and return. */
|
|---|
| 27 | static char *members[64]; /* Group members with the entry. */
|
|---|
| 28 | static int grfd= -1; /* Filedescriptor to the file. */
|
|---|
| 29 | static char *bufptr; /* Place in buf. */
|
|---|
| 30 | static ssize_t buflen= 0; /* Remaining characters in buf. */
|
|---|
| 31 | static char *lineptr; /* Place in the line. */
|
|---|
| 32 |
|
|---|
| 33 | void endgrent(void)
|
|---|
| 34 | /* Close the group file. */
|
|---|
| 35 | {
|
|---|
| 36 | if (grfd >= 0) {
|
|---|
| 37 | (void) close(grfd);
|
|---|
| 38 | grfd= -1;
|
|---|
| 39 | buflen= 0;
|
|---|
| 40 | }
|
|---|
| 41 | }
|
|---|
| 42 |
|
|---|
| 43 | int setgrent(void)
|
|---|
| 44 | /* Open the group file. */
|
|---|
| 45 | {
|
|---|
| 46 | if (grfd >= 0) endgrent();
|
|---|
| 47 |
|
|---|
| 48 | if (grfile == nil) grfile= GROUP;
|
|---|
| 49 |
|
|---|
| 50 | if ((grfd= open(grfile, O_RDONLY)) < 0) return -1;
|
|---|
| 51 | (void) fcntl(grfd, F_SETFD, fcntl(grfd, F_GETFD) | FD_CLOEXEC);
|
|---|
| 52 | return 0;
|
|---|
| 53 | }
|
|---|
| 54 |
|
|---|
| 55 | void setgrfile(const char *file)
|
|---|
| 56 | /* Prepare for reading an alternate group file. */
|
|---|
| 57 | {
|
|---|
| 58 | endgrent();
|
|---|
| 59 | grfile= file;
|
|---|
| 60 | }
|
|---|
| 61 |
|
|---|
| 62 | static int getline(void)
|
|---|
| 63 | /* Get one line from the group file, return 0 if bad or EOF. */
|
|---|
| 64 | {
|
|---|
| 65 | lineptr= grline;
|
|---|
| 66 |
|
|---|
| 67 | do {
|
|---|
| 68 | if (buflen == 0) {
|
|---|
| 69 | if ((buflen= read(grfd, buf, sizeof(buf))) <= 0)
|
|---|
| 70 | return 0;
|
|---|
| 71 | bufptr= buf;
|
|---|
| 72 | }
|
|---|
| 73 |
|
|---|
| 74 | if (lineptr == arraylimit(grline)) return 0;
|
|---|
| 75 | buflen--;
|
|---|
| 76 | } while ((*lineptr++ = *bufptr++) != '\n');
|
|---|
| 77 |
|
|---|
| 78 | lineptr= grline;
|
|---|
| 79 | return 1;
|
|---|
| 80 | }
|
|---|
| 81 |
|
|---|
| 82 | static char *scan_punct(int punct)
|
|---|
| 83 | /* Scan for a field separator in a line, return the start of the field. */
|
|---|
| 84 | {
|
|---|
| 85 | char *field= lineptr;
|
|---|
| 86 | char *last;
|
|---|
| 87 |
|
|---|
| 88 | for (;;) {
|
|---|
| 89 | last= lineptr;
|
|---|
| 90 | if (*lineptr == 0) return nil;
|
|---|
| 91 | if (*lineptr == '\n') break;
|
|---|
| 92 | if (*lineptr++ == punct) break;
|
|---|
| 93 | if (lineptr[-1] == ':') return nil; /* :::,,,:,,,? */
|
|---|
| 94 | }
|
|---|
| 95 | *last= 0;
|
|---|
| 96 | return field;
|
|---|
| 97 | }
|
|---|
| 98 |
|
|---|
| 99 | struct group *getgrent(void)
|
|---|
| 100 | /* Read one entry from the group file. */
|
|---|
| 101 | {
|
|---|
| 102 | char *p;
|
|---|
| 103 | char **mem;
|
|---|
| 104 |
|
|---|
| 105 | /* Open the file if not yet open. */
|
|---|
| 106 | if (grfd < 0 && setgrent() < 0) return nil;
|
|---|
| 107 |
|
|---|
| 108 | /* Until a good line is read. */
|
|---|
| 109 | for (;;) {
|
|---|
| 110 | if (!getline()) return nil; /* EOF or corrupt. */
|
|---|
| 111 |
|
|---|
| 112 | if ((entry.gr_name= scan_punct(':')) == nil) continue;
|
|---|
| 113 | if ((entry.gr_passwd= scan_punct(':')) == nil) continue;
|
|---|
| 114 | if ((p= scan_punct(':')) == nil) continue;
|
|---|
| 115 | entry.gr_gid= strtol(p, nil, 0);
|
|---|
| 116 |
|
|---|
| 117 | entry.gr_mem= mem= members;
|
|---|
| 118 | if (*lineptr != '\n') {
|
|---|
| 119 | do {
|
|---|
| 120 | if ((*mem= scan_punct(',')) == nil) goto again;
|
|---|
| 121 | if (mem < arraylimit(members) - 1) mem++;
|
|---|
| 122 | } while (*lineptr != 0);
|
|---|
| 123 | }
|
|---|
| 124 | *mem= nil;
|
|---|
| 125 | return &entry;
|
|---|
| 126 | again:;
|
|---|
| 127 | }
|
|---|
| 128 | }
|
|---|
| 129 |
|
|---|
| 130 | struct group *getgrgid(_mnx_Gid_t gid)
|
|---|
| 131 | /* Return the group file entry belonging to the user-id. */
|
|---|
| 132 | {
|
|---|
| 133 | struct group *gr;
|
|---|
| 134 |
|
|---|
| 135 | endgrent();
|
|---|
| 136 | while ((gr= getgrent()) != nil && gr->gr_gid != gid) {}
|
|---|
| 137 | endgrent();
|
|---|
| 138 | return gr;
|
|---|
| 139 | }
|
|---|
| 140 |
|
|---|
| 141 | struct group *getgrnam(const char *name)
|
|---|
| 142 | /* Return the group file entry belonging to the user name. */
|
|---|
| 143 | {
|
|---|
| 144 | struct group *gr;
|
|---|
| 145 |
|
|---|
| 146 | endgrent();
|
|---|
| 147 | while ((gr= getgrent()) != nil && strcmp(gr->gr_name, name) != 0) {}
|
|---|
| 148 | endgrent();
|
|---|
| 149 | return gr;
|
|---|
| 150 | }
|
|---|
