diff options
Diffstat (limited to 'usr/src/lib/libast/common/preroot/getpreroot.c')
| -rw-r--r-- | usr/src/lib/libast/common/preroot/getpreroot.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/usr/src/lib/libast/common/preroot/getpreroot.c b/usr/src/lib/libast/common/preroot/getpreroot.c new file mode 100644 index 0000000000..a35915d52d --- /dev/null +++ b/usr/src/lib/libast/common/preroot/getpreroot.c @@ -0,0 +1,165 @@ +/*********************************************************************** +* * +* This software is part of the ast package * +* Copyright (c) 1985-2007 AT&T Knowledge Ventures * +* and is licensed under the * +* Common Public License, Version 1.0 * +* by AT&T Knowledge Ventures * +* * +* A copy of the License is available at * +* http://www.opensource.org/licenses/cpl1.0.txt * +* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * +* * +* Information and Software Systems Research * +* AT&T Research * +* Florham Park NJ * +* * +* Glenn Fowler <gsf@research.att.com> * +* David Korn <dgk@research.att.com> * +* Phong Vo <kpv@research.att.com> * +* * +***********************************************************************/ +#pragma prototyped +/* + * AT&T Bell Laboratories + * return the real absolute pathname of the preroot dir for cmd + * if cmd==0 then current preroot path returned + */ + +#include <ast.h> +#include <preroot.h> + +#if FS_PREROOT + +#include <ast_dir.h> +#include <ls.h> +#include <error.h> +#include <stdio.h> + +#ifndef ERANGE +#define ERANGE E2BIG +#endif + +#define ERROR(e) {errno=e;goto error;} + +char* +getpreroot(char* path, const char* cmd) +{ + register int c; + register FILE* fp; + register char* p; + char buf[PATH_MAX]; + + if (!path) path = buf; + if (cmd) + { + sfsprintf(buf, sizeof(buf), "set x `%s= %s - </dev/null 2>&1`\nwhile :\ndo\nshift\ncase $# in\n[012]) break ;;\nesac\ncase \"$1 $2\" in\n\"+ %s\") echo $3; exit ;;\nesac\ndone\necho\n", PR_SILENT, cmd, PR_COMMAND); + if (!(fp = popen(buf, "rug"))) return(0); + for (p = path; (c = getc(fp)) != EOF && c != '\n'; *p++ = c); + *p = 0; + pclose(fp); + if (path == p) return(0); + return(path == buf ? strdup(path) : path); + } + else + { + char* d; + DIR* dirp = 0; + int namlen; + int euid; + int ruid; + struct dirent* entry; + struct stat* cur; + struct stat* par; + struct stat* tmp; + struct stat curst; + struct stat parst; + struct stat tstst; + char dots[PATH_MAX]; + + cur = &curst; + par = &parst; + if ((ruid = getuid()) != (euid = geteuid())) setuid(ruid); + if (stat(PR_REAL, cur) || stat("/", par) || cur->st_dev == par->st_dev && cur->st_ino == par->st_ino) ERROR(ENOTDIR); + + /* + * like getcwd() but starting at the preroot + */ + + d = dots; + *d++ = '/'; + p = path + PATH_MAX - 1; + *p = 0; + for (;;) + { + tmp = cur; + cur = par; + par = tmp; + if ((d - dots) > (PATH_MAX - 4)) ERROR(ERANGE); + *d++ = '.'; + *d++ = '.'; + *d = 0; + if (!(dirp = opendir(dots))) ERROR(errno); +#if !_dir_ok || _mem_dd_fd_DIR + if (fstat(dirp->dd_fd, par)) ERROR(errno); +#else + if (stat(dots, par)) ERROR(errno); +#endif + *d++ = '/'; + if (par->st_dev == cur->st_dev) + { + if (par->st_ino == cur->st_ino) + { + closedir(dirp); + *--p = '/'; + if (ruid != euid) setuid(euid); + if (path == buf) return(strdup(p)); + if (path != p) + { + d = path; + while (*d++ = *p++); + } + return(path); + } +#ifdef D_FILENO + while (entry = readdir(dirp)) + if (D_FILENO(entry) == cur->st_ino) + { + namlen = D_NAMLEN(entry); + goto found; + } +#endif + + /* + * this fallthrough handles logical naming + */ + + rewinddir(dirp); + } + do + { + if (!(entry = readdir(dirp))) ERROR(ENOENT); + namlen = D_NAMLEN(entry); + if ((d - dots) > (PATH_MAX - 1 - namlen)) ERROR(ERANGE); + memcpy(d, entry->d_name, namlen + 1); + if (stat(dots, &tstst)) ERROR(errno); + } while (tstst.st_ino != cur->st_ino || tstst.st_dev != cur->st_dev); + found: + if (*p) *--p = '/'; + if ((p -= namlen) <= (path + 1)) ERROR(ERANGE); + memcpy(p, entry->d_name, namlen); + closedir(dirp); + dirp = 0; + } + error: + if (dirp) closedir(dirp); + if (ruid != euid) setuid(euid); + } + return(0); +} + +#else + +NoN(getpreroot) + +#endif |