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Diffstat (limited to 'libpwdgrp/__getgrent.c')
| -rw-r--r-- | libpwdgrp/__getgrent.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/libpwdgrp/__getgrent.c b/libpwdgrp/__getgrent.c new file mode 100644 index 0000000..571da3f --- /dev/null +++ b/libpwdgrp/__getgrent.c @@ -0,0 +1,204 @@ +/* + * __getgrent.c - This file is part of the libc-8086/grp package for ELKS, + * Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the Free + * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +#include "busybox.h" + +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include "grp.h" + +/* + * Define GR_SCALE_DYNAMIC if you want grp to dynamically scale its read buffer + * so that lines of any length can be used. On very very small systems, + * you may want to leave this undefined becasue it will make the grp functions + * somewhat larger (because of the inclusion of malloc and the code necessary). + * On larger systems, you will want to define this, because grp will _not_ + * deal with long lines gracefully (they will be skipped). + */ +#undef GR_SCALE_DYNAMIC + +#ifndef GR_SCALE_DYNAMIC +/* + * If scaling is not dynamic, the buffers will be statically allocated, and + * maximums must be chosen. GR_MAX_LINE_LEN is the maximum number of + * characters per line in the group file. GR_MAX_MEMBERS is the maximum + * number of members of any given group. + */ +#define GR_MAX_LINE_LEN 128 +/* GR_MAX_MEMBERS = (GR_MAX_LINE_LEN-(24+3+6))/9 */ +#define GR_MAX_MEMBERS 11 + +#endif /* !GR_SCALE_DYNAMIC */ + + +/* + * Define GR_DYNAMIC_GROUP_LIST to make initgroups() dynamically allocate + * space for it's GID array before calling setgroups(). This is probably + * unnecessary scalage, so it's undefined by default. + */ +#undef GR_DYNAMIC_GROUP_LIST + +#ifndef GR_DYNAMIC_GROUP_LIST +/* + * GR_MAX_GROUPS is the size of the static array initgroups() uses for + * its static GID array if GR_DYNAMIC_GROUP_LIST isn't defined. + */ +#define GR_MAX_GROUPS 64 + +#endif /* !GR_DYNAMIC_GROUP_LIST */ + + +/* + * This is the core group-file read function. It behaves exactly like + * getgrent() except that it is passed a file descriptor. getgrent() + * is just a wrapper for this function. + */ +struct group *__getgrent(int grp_fd) +{ +#ifndef GR_SCALE_DYNAMIC + static char line_buff[GR_MAX_LINE_LEN]; + static char *members[GR_MAX_MEMBERS]; +#else + static char *line_buff = NULL; + static char **members = NULL; + short line_index; + short buff_size; +#endif + static struct group group; + register char *ptr; + char *field_begin; + short member_num; + char *endptr; + int line_len; + + + /* We use the restart label to handle malformatted lines */ + restart: +#ifdef GR_SCALE_DYNAMIC + line_index = 0; + buff_size = 256; +#endif + +#ifndef GR_SCALE_DYNAMIC + /* Read the line into the static buffer */ + if ((line_len = read(grp_fd, line_buff, GR_MAX_LINE_LEN)) <= 0) + return NULL; + field_begin = strchr(line_buff, '\n'); + if (field_begin != NULL) + lseek(grp_fd, (long) (1 + field_begin - (line_buff + line_len)), + SEEK_CUR); + else { /* The line is too long - skip it :-\ */ + + do { + if ((line_len = read(grp_fd, line_buff, GR_MAX_LINE_LEN)) <= 0) + return NULL; + } while (!(field_begin = strchr(line_buff, '\n'))); + lseek(grp_fd, (long) ((field_begin - line_buff) - line_len + 1), + SEEK_CUR); + goto restart; + } + if (*line_buff == '#' || *line_buff == ' ' || *line_buff == '\n' || + *line_buff == '\t') + goto restart; + *field_begin = '\0'; + +#else /* !GR_SCALE_DYNAMIC */ + line_buff = realloc(line_buff, buff_size); + while (1) { + if ((line_len = read(grp_fd, line_buff + line_index, + buff_size - line_index)) <= 0) + return NULL; + field_begin = strchr(line_buff, '\n'); + if (field_begin != NULL) { + lseek(grp_fd, + (long) (1 + field_begin - + (line_len + line_index + line_buff)), SEEK_CUR); + *field_begin = '\0'; + if (*line_buff == '#' || *line_buff == ' ' + || *line_buff == '\n' || *line_buff == '\t') + goto restart; + break; + } else { /* Allocate some more space */ + + line_index = buff_size; + buff_size += 256; + line_buff = realloc(line_buff, buff_size); + } + } +#endif /* GR_SCALE_DYNAMIC */ + + /* Now parse the line */ + group.gr_name = line_buff; + ptr = strchr(line_buff, ':'); + if (ptr == NULL) + goto restart; + *ptr++ = '\0'; + + group.gr_passwd = ptr; + ptr = strchr(ptr, ':'); + if (ptr == NULL) + goto restart; + *ptr++ = '\0'; + + field_begin = ptr; + ptr = strchr(ptr, ':'); + if (ptr == NULL) + goto restart; + *ptr++ = '\0'; + + group.gr_gid = (gid_t) strtoul(field_begin, &endptr, 10); + if (*endptr != '\0') + goto restart; + + member_num = 0; + field_begin = ptr; + +#ifndef GR_SCALE_DYNAMIC + while ((ptr = strchr(ptr, ',')) != NULL) { + *ptr = '\0'; + ptr++; + members[member_num] = field_begin; + field_begin = ptr; + member_num++; + } + if (*field_begin == '\0') + members[member_num] = NULL; + else { + members[member_num] = field_begin; + members[member_num + 1] = NULL; + } +#else /* !GR_SCALE_DYNAMIC */ + if (members != NULL) + free(members); + members = (char **) malloc((member_num + 1) * sizeof(char *)); + for ( ; field_begin && *field_begin != '\0'; field_begin = ptr) { + if ((ptr = strchr(field_begin, ',')) != NULL) + *ptr++ = '\0'; + members[member_num++] = field_begin; + members = (char **) realloc(members, + (member_num + 1) * sizeof(char *)); + } + members[member_num] = NULL; +#endif /* GR_SCALE_DYNAMIC */ + + group.gr_mem = members; + return &group; +} |