/* $Id: sysfs.cpp 33540 2010-10-28 09:27:05Z vboxsync $ */ /** @file * IPRT - Linux sysfs access. */ /* * Copyright (C) 2006-2008 Oracle Corporation * * This file is part of VirtualBox Open Source Edition (OSE), as * available from http://www.virtualbox.org. This file is free software; * you can redistribute it and/or modify it under the terms of the GNU * General Public License (GPL) as published by the Free Software * Foundation, in version 2 as it comes in the "COPYING" file of the * VirtualBox OSE distribution. VirtualBox OSE is distributed in the * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. * * The contents of this file may alternatively be used under the terms * of the Common Development and Distribution License Version 1.0 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the * VirtualBox OSE distribution, in which case the provisions of the * CDDL are applicable instead of those of the GPL. * * You may elect to license modified versions of this file under the * terms and conditions of either the GPL or the CDDL or both. */ /******************************************************************************* * Header Files * *******************************************************************************/ #define LOG_GROUP RTLOGGROUP_SYSTEM #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** @todo r=bird: This whole API should be rewritten to use IPRT status codes. * using errno was a mistake and only results in horrible code. */ /** * Constructs the path of a sysfs file from the format parameters passed, * prepending a prefix if the path is relative. * * @returns The number of characters returned, or -1 and errno set to ERANGE on * failure. * * @param pszPrefix The prefix to prepend if the path is relative. Must end * in '/'. * @param pszBuf Where to write the path. Must be at least * sizeof(@a pszPrefix) characters long * @param cchBuf The size of the buffer pointed to by @a pszBuf. * @param pszFormat The name format, either absolute or relative to the * prefix specified by @a pszPrefix. * @param va The format args. */ static ssize_t rtLinuxConstructPathV(char *pszBuf, size_t cchBuf, const char *pszPrefix, const char *pszFormat, va_list va) { size_t cchPrefix = strlen(pszPrefix); AssertReturnStmt(pszPrefix[cchPrefix - 1] == '/', errno = ERANGE, -1); AssertReturnStmt(cchBuf > cchPrefix + 1, errno = ERANGE, -1); /** @todo While RTStrPrintfV prevents overflows, it doesn't make it easy to * check for truncations. RTPath should provide some formatters and * joiners which can take over this rather common task that is * performed here. */ size_t cch = RTStrPrintfV(pszBuf, cchBuf, pszFormat, va); if (*pszBuf != '/') { AssertReturnStmt(cchBuf >= cch + cchPrefix + 1, errno = ERANGE, -1); memmove(pszBuf + cchPrefix, pszBuf, cch + 1); memcpy(pszBuf, pszPrefix, cchPrefix); cch += cchPrefix; } return cch; } /** * Constructs the path of a sysfs file from the format parameters passed, * prepending a prefix if the path is relative. * * @returns The number of characters returned, or -1 and errno set to ERANGE on * failure. * * @param pszPrefix The prefix to prepend if the path is relative. Must end * in '/'. * @param pszBuf Where to write the path. Must be at least * sizeof(@a pszPrefix) characters long * @param cchBuf The size of the buffer pointed to by @a pszBuf. * @param pszFormat The name format, either absolute or relative to "/sys/". * @param ... The format args. */ static ssize_t rtLinuxConstructPath(char *pszBuf, size_t cchBuf, const char *pszPrefix, const char *pszFormat, ...) { va_list va; va_start(va, pszFormat); int rc = rtLinuxConstructPathV(pszBuf, cchBuf, pszPrefix, pszFormat, va); va_end(va); return rc; } /** * Constructs the path of a sysfs file from the format parameters passed, * prepending "/sys/" if the path is relative. * * @returns The number of characters returned, or -1 and errno set to ERANGE on * failure. * * @param pszBuf Where to write the path. Must be at least * sizeof("/sys/") characters long * @param cchBuf The size of the buffer pointed to by @a pszBuf. * @param pszFormat The name format, either absolute or relative to "/sys/". * @param va The format args. */ static ssize_t rtLinuxSysFsConstructPath(char *pszBuf, size_t cchBuf, const char *pszFormat, va_list va) { return rtLinuxConstructPathV(pszBuf, cchBuf, "/sys/", pszFormat, va); } RTDECL(bool) RTLinuxSysFsExistsV(const char *pszFormat, va_list va) { int iSavedErrno = errno; /* * Construct the filename and call stat. */ bool fRet = false; char szFilename[RTPATH_MAX]; ssize_t rc = rtLinuxSysFsConstructPath(szFilename, sizeof(szFilename), pszFormat, va); if (rc != -1) { struct stat st; fRet = stat(szFilename, &st) == 0; } errno = iSavedErrno; return fRet; } RTDECL(bool) RTLinuxSysFsExists(const char *pszFormat, ...) { va_list va; va_start(va, pszFormat); bool fRet = RTLinuxSysFsExistsV(pszFormat, va); va_end(va); return fRet; } RTDECL(int) RTLinuxSysFsOpenV(const char *pszFormat, va_list va) { /* * Construct the filename and call open. */ char szFilename[RTPATH_MAX]; ssize_t rc = rtLinuxSysFsConstructPath(szFilename, sizeof(szFilename), pszFormat, va); if (rc != -1) rc = open(szFilename, O_RDONLY, 0); return rc; } RTDECL(int) RTLinuxSysFsOpen(const char *pszFormat, ...) { va_list va; va_start(va, pszFormat); int fd = RTLinuxSysFsOpenV(pszFormat, va); va_end(va); return fd; } RTDECL(void) RTLinuxSysFsClose(int fd) { int iSavedErrno = errno; close(fd); errno = iSavedErrno; } RTDECL(ssize_t) RTLinuxSysFsReadStr(int fd, char *pszBuf, size_t cchBuf) { Assert(cchBuf > 1); ssize_t cchRead = read(fd, pszBuf, cchBuf - 1); pszBuf[cchRead >= 0 ? cchRead : 0] = '\0'; return cchRead; } RTDECL(int) RTLinuxSysFsReadFile(int fd, void *pvBuf, size_t cbBuf, size_t *pcbRead) { int rc; ssize_t cbRead = read(fd, pvBuf, cbBuf); if (cbRead >= 0) { if (pcbRead) *pcbRead = cbRead; if ((size_t)cbRead < cbBuf) rc = VINF_SUCCESS; else { /* Check for EOF */ char ch; off_t off = lseek(fd, 0, SEEK_CUR); ssize_t cbRead2 = read(fd, &ch, 1); if (cbRead2 == 0) rc = VINF_SUCCESS; else if (cbRead2 > 0) { lseek(fd, off, SEEK_SET); rc = VERR_BUFFER_OVERFLOW; } else rc = RTErrConvertFromErrno(errno); } } else rc = RTErrConvertFromErrno(errno); return rc; } RTDECL(int64_t) RTLinuxSysFsReadIntFileV(unsigned uBase, const char *pszFormat, va_list va) { int fd = RTLinuxSysFsOpenV(pszFormat, va); if (fd == -1) return -1; int64_t i64Ret = -1; char szNum[128]; ssize_t cchNum = RTLinuxSysFsReadStr(fd, szNum, sizeof(szNum)); if (cchNum > 0) { int rc = RTStrToInt64Ex(szNum, NULL, uBase, &i64Ret); if (RT_FAILURE(rc)) { i64Ret = -1; errno = -ETXTBSY; /* just something that won't happen at read / open. */ } } else if (cchNum == 0) errno = -ETXTBSY; /* just something that won't happen at read / open. */ RTLinuxSysFsClose(fd); return i64Ret; } RTDECL(int64_t) RTLinuxSysFsReadIntFile(unsigned uBase, const char *pszFormat, ...) { va_list va; va_start(va, pszFormat); int64_t i64Ret = RTLinuxSysFsReadIntFileV(uBase, pszFormat, va); va_end(va); return i64Ret; } RTDECL(dev_t) RTLinuxSysFsReadDevNumFileV(const char *pszFormat, va_list va) { int fd = RTLinuxSysFsOpenV(pszFormat, va); if (fd == -1) return 0; dev_t DevNum = 0; char szNum[128]; ssize_t cchNum = RTLinuxSysFsReadStr(fd, szNum, sizeof(szNum)); if (cchNum > 0) { uint32_t u32Maj = 0; uint32_t u32Min = 0; char *pszNext = NULL; int rc = RTStrToUInt32Ex(szNum, &pszNext, 10, &u32Maj); if (RT_FAILURE(rc) || (rc != VWRN_TRAILING_CHARS) || (*pszNext != ':')) errno = EINVAL; else { rc = RTStrToUInt32Ex(pszNext + 1, NULL, 10, &u32Min); if ( rc != VINF_SUCCESS && rc != VWRN_TRAILING_CHARS && rc != VWRN_TRAILING_SPACES) errno = EINVAL; else { errno = 0; DevNum = makedev(u32Maj, u32Min); } } } else if (cchNum == 0) errno = EINVAL; RTLinuxSysFsClose(fd); return DevNum; } RTDECL(dev_t) RTLinuxSysFsReadDevNumFile(const char *pszFormat, ...) { va_list va; va_start(va, pszFormat); dev_t DevNum = RTLinuxSysFsReadDevNumFileV(pszFormat, va); va_end(va); return DevNum; } RTDECL(ssize_t) RTLinuxSysFsReadStrFileV(char *pszBuf, size_t cchBuf, const char *pszFormat, va_list va) { int fd = RTLinuxSysFsOpenV(pszFormat, va); if (fd == -1) return -1; ssize_t cchRet = RTLinuxSysFsReadStr(fd, pszBuf, cchBuf); RTLinuxSysFsClose(fd); if (cchRet > 0) { char *pchNewLine = (char *)memchr(pszBuf, '\n', cchRet); if (pchNewLine) *pchNewLine = '\0'; } return cchRet; } RTDECL(ssize_t) RTLinuxSysFsReadStrFile(char *pszBuf, size_t cchBuf, const char *pszFormat, ...) { va_list va; va_start(va, pszFormat); ssize_t cchRet = RTLinuxSysFsReadStrFileV(pszBuf, cchBuf, pszFormat, va); va_end(va); return cchRet; } RTDECL(ssize_t) RTLinuxSysFsGetLinkDestV(char *pszBuf, size_t cchBuf, const char *pszFormat, va_list va) { AssertReturnStmt(cchBuf >= 2, errno = EINVAL, -1); /* * Construct the filename and read the link. */ char szFilename[RTPATH_MAX]; int rc = rtLinuxSysFsConstructPath(szFilename, sizeof(szFilename), pszFormat, va); if (rc == -1) return -1; char szLink[RTPATH_MAX]; rc = readlink(szFilename, szLink, sizeof(szLink)); if (rc == -1) return -1; if ((size_t)rc > sizeof(szLink) - 1) { errno = ERANGE; return -1; } szLink[rc] = '\0'; /* readlink fun. */ /* * Extract the file name component and copy it into the return buffer. */ size_t cchName; const char *pszName = RTPathFilename(szLink); if (pszName) { cchName = strlen(pszName); /* = &szLink[rc] - pszName; */ if (cchName >= cchBuf) { errno = ERANGE; return -1; } memcpy(pszBuf, pszName, cchName + 1); } else { *pszBuf = '\0'; cchName = 0; } return cchName; } RTDECL(ssize_t) RTLinuxSysFsGetLinkDest(char *pszBuf, size_t cchBuf, const char *pszFormat, ...) { va_list va; va_start(va, pszFormat); int rc = RTLinuxSysFsGetLinkDestV(pszBuf, cchBuf, pszFormat, va); va_end(va); return rc; } static ssize_t rtLinuxFindDevicePathRecursive(dev_t DevNum, RTFMODE fMode, const char *pszBasePath, char *pszBuf, size_t cchBuf) { /* * Check assumptions made by the code below. */ size_t const cchBasePath = strlen(pszBasePath); AssertReturnStmt(cchBasePath < RTPATH_MAX - 10U, errno = ENAMETOOLONG, -1); ssize_t rcRet; PRTDIR pDir; int rc = RTDirOpen(&pDir, pszBasePath); if (RT_SUCCESS(rc)) { char szPath[RTPATH_MAX]; /** @todo 4K per recursion - can easily be optimized away by passing it along pszBasePath and only remember the length. */ memcpy(szPath, pszBasePath, cchBasePath + 1); for (;;) { RTDIRENTRYEX Entry; rc = RTDirReadEx(pDir, &Entry, NULL, RTFSOBJATTRADD_UNIX, RTPATH_F_ON_LINK); if (RT_FAILURE(rc)) { errno = rc == VERR_NO_MORE_FILES ? ENOENT : rc == VERR_BUFFER_OVERFLOW ? EOVERFLOW : EIO; rcRet = -1; break; } if (RTFS_IS_SYMLINK(Entry.Info.Attr.fMode)) continue; /* Do the matching. */ if ( Entry.Info.Attr.u.Unix.Device == DevNum && (Entry.Info.Attr.fMode & RTFS_TYPE_MASK) == fMode) { rcRet = rtLinuxConstructPath(pszBuf, cchBuf, pszBasePath, "%s", Entry.szName); break; } /* Recurse into subdirectories. */ if (!RTFS_IS_DIRECTORY(Entry.Info.Attr.fMode)) continue; if (Entry.szName[0] == '.') continue; szPath[cchBasePath] = '\0'; rc = RTPathAppend(szPath, sizeof(szPath) - 1, Entry.szName); /* -1: for slash */ if (RT_FAILURE(rc)) { errno = ENAMETOOLONG; rcRet = -1; break; } strcat(&szPath[cchBasePath], "/"); rcRet = rtLinuxFindDevicePathRecursive(DevNum, fMode, szPath, pszBuf, cchBuf); if (rcRet >= 0 || errno != ENOENT) break; } RTDirClose(pDir); } else { rcRet = -1; errno = RTErrConvertToErrno(rc); } return rcRet; } RTDECL(ssize_t) RTLinuxFindDevicePathV(dev_t DevNum, RTFMODE fMode, char *pszBuf, size_t cchBuf, const char *pszSuggestion, va_list va) { AssertReturnStmt(cchBuf >= 2, errno = EINVAL, -1); AssertReturnStmt( fMode == RTFS_TYPE_DEV_CHAR || fMode == RTFS_TYPE_DEV_BLOCK, errno = EINVAL, -1); if (pszSuggestion) { /* * Construct the filename and read the link. */ char szFilename[RTPATH_MAX]; int rc = rtLinuxConstructPathV(szFilename, sizeof(szFilename), "/dev/", pszSuggestion, va); if (rc == -1) return -1; /* * Check whether the caller's suggestion was right. */ RTFSOBJINFO Info; rc = RTPathQueryInfo(szFilename, &Info, RTFSOBJATTRADD_UNIX); if ( RT_SUCCESS(rc) && Info.Attr.u.Unix.Device == DevNum && (Info.Attr.fMode & RTFS_TYPE_MASK) == fMode) { size_t cchPath = strlen(szFilename); if (cchPath >= cchBuf) { errno = EOVERFLOW; return -1; } memcpy(pszBuf, szFilename, cchPath + 1); return cchPath; } /* The suggestion was wrong, fall back on the brute force attack. */ } return rtLinuxFindDevicePathRecursive(DevNum, fMode, "/dev/", pszBuf, cchBuf); } RTDECL(ssize_t) RTLinuxFindDevicePath(dev_t DevNum, RTFMODE fMode, char *pszBuf, size_t cchBuf, const char *pszSuggestion, ...) { va_list va; va_start(va, pszSuggestion); int rc = RTLinuxFindDevicePathV(DevNum, fMode, pszBuf, cchBuf, pszSuggestion, va); va_end(va); return rc; }