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[/] [eco32/] [tags/] [eco32-0.23/] [disk/] [tools/] [fs-NetBSD/] [loader/] [loader.c] - Rev 272
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/* * loader.c -- the NetBSD system loader */ #include "types.h" #include "disklabel.h" #include "fs.h" #include "dinode.h" #include "dir.h" #include "stdarg.h" #include "auxlib.h" #include "biolib.h" #include "elf.h" /**************************************************************/ /* constants and data types */ #define DFLT_KERNEL "/netbsd" /* default path to kernel */ #define MAX_LINE 100 /* line buffer size */ #define SSHIFT 9 /* ld of sector size */ #define SSIZE (1 << SSHIFT) /* disk sector size in bytes */ #define SMASK (SSIZE - 1) /* sector mask */ #define BSHIFT 13 /* ld of block size */ #define BSIZE (1 << BSHIFT) /* disk block size in bytes */ #define BMASK (BSIZE - 1) /* block mask */ typedef struct ufs1_dinode Dinode; typedef struct direct Dirent; typedef unsigned int daddr_t; typedef unsigned int ino_t; #define NIPB (BSIZE / sizeof(Dinode)) #define NULL 0 /**************************************************************/ /* debugging */ Bool debugReadSectors = FALSE; Bool debugReadDiskLabel = FALSE; Bool debugReadSuperBlock = FALSE; Bool debugGetInode = FALSE; Bool debugSearchDir = FALSE; Bool debugLoadElf = FALSE; /**************************************************************/ /* halt with error message */ void halt(char *msg) { printf("%s, machine halted.\n", msg); while (1) ; } /**************************************************************/ /* disk I/O */ unsigned int bootDisk = 0; /* gets loaded by previous stage */ /* never changed */ unsigned int startSector = 0; /* gets loaded by previous stage */ /* initially holds start of slice */ /* disklabel read --> start of partition */ unsigned int numSectors = 0; /* gets loaded by previous stage */ /* initially holds size of slice */ /* disklabel read --> size of partition */ unsigned int spf; /* superblock read --> sectors per fragment */ unsigned int spb; /* superblock read --> sectors per block */ /* * read disk sectors * * NOTE: buffer must be word-aligned */ void readSectors(unsigned int start, unsigned int count, void *buffer) { unsigned int sector; int result; if (start + count > numSectors) { halt("Sector number exceeds slice or partition size"); } sector = startSector + start; if (debugReadSectors) { printf("DEBUG: reading sector 0x%08X, %d sectors\n", sector, count); } result = rwscts(bootDisk, 'r', sector, (unsigned int) buffer & 0x3FFFFFFF, count); if (result != 0) { halt("Load error"); } } /**************************************************************/ /* disklabel handling */ unsigned int diskLabel[SSIZE / sizeof(unsigned int)]; DiskLabel *dlp = (DiskLabel *) &diskLabel[0]; unsigned int superStart; /* partition-relative offset, in sectors */ unsigned int superSize; /* size, in sectors */ void readDiskLabel(void) { readSectors(1, 1, dlp); if (dlp->d_magic != DSKMAGIC || dlp->d_magic2 != DSKMAGIC) { halt("Disklabel corrupted"); } startSector = dlp->d_parts[0].p_offset; numSectors = dlp->d_parts[0].p_size; superStart = dlp->d_bbsize; if ((superStart & SMASK) != 0) { halt("Superblock offset is not multiple of sector size"); } superStart >>= SSHIFT; superSize = dlp->d_sbsize; if ((superSize & SMASK) != 0) { halt("Superblock size is not multiple of sector size"); } if (superSize > BSIZE) { halt("Superblock too big"); } superSize >>= SSHIFT; if (debugReadDiskLabel) { printf("DEBUG: super start = %d sectors, super size = %d sectors\n", superStart, superSize); } } /**************************************************************/ /* superblock handling */ unsigned int superBlock[BSIZE / sizeof(unsigned int)]; struct fs *sbp = (struct fs *) &superBlock[0]; void readSuperBlock(void) { readSectors(superStart, superSize, sbp); if (sbp->fs_magic != FS_UFS1_MAGIC) { halt("Wrong magic number in superblock"); } spf = sbp->fs_fsize / SSIZE; spb = sbp->fs_bsize / SSIZE; if (sbp->fs_inopb != NIPB) { halt("Wrong number of inodes per block"); } if (debugReadSuperBlock) { printf("DEBUG: %d sectors per fragment\n", spf); printf("DEBUG: %d sectors per block\n", spb); printf("DEBUG: %d inodes per block\n", NIPB); } } /**************************************************************/ /* file operations */ unsigned int sibno = 0; unsigned int sib[8192 / sizeof(unsigned int)]; unsigned int *sibp = (unsigned int *) &sib[0]; /* * read a block of a file * * NOTE: addr must be word-aligned */ void readFileBlock(Dinode *ip, int blkno, void *addr) { unsigned int diskFrag; if (blkno < NDADDR) { /* direct block */ diskFrag = ip->di_db[blkno]; } else if (blkno - NDADDR < sbp->fs_bsize / sizeof(int32_t)) { /* single indirect block */ if (sibno != ip->di_ib[0]) { sibno = ip->di_ib[0]; readSectors(sibno * spf, spb, sibp); } diskFrag = sibp[blkno - NDADDR]; } else { /* double or triple indirect blocks */ halt("Cannot do double or triple indirect blocks"); } readSectors(diskFrag * spf, spb, addr); } /* * read a number of bytes from a file */ void readFile(Dinode *ip, unsigned int offset, unsigned int size, void *buffer) { unsigned int dskblk[8192 / sizeof(unsigned int)]; unsigned char *bufp; unsigned char *blkp; unsigned int blkno; unsigned int index; unsigned int aux; unsigned int numBytes; int i; bufp = (unsigned char *) buffer; blkp = (unsigned char *) dskblk; blkno = offset / sbp->fs_bsize; index = offset % sbp->fs_bsize; aux = sbp->fs_bsize - index; numBytes = (size <= aux) ? size : aux; readFileBlock(ip, blkno, blkp); for (i = 0; i < numBytes; i++) { *bufp++ = blkp[index++]; } blkno++; size -= numBytes; while (size >= sbp->fs_bsize) { index = 0; numBytes = sbp->fs_bsize; readFileBlock(ip, blkno, blkp); for (i = 0; i < numBytes; i++) { *bufp++ = blkp[index++]; } blkno++; size -= numBytes; } if (size > 0) { index = 0; numBytes = size; readFileBlock(ip, blkno, blkp); for (i = 0; i < numBytes; i++) { *bufp++ = blkp[index++]; } } } /**************************************************************/ /* inode handling */ unsigned int inodeBlock[BSIZE / sizeof(unsigned int)]; Dinode *ibp = (Dinode *) &inodeBlock[0]; Dinode *getInode(unsigned int inode) { unsigned int fnum; unsigned int inum; Dinode *ip; fnum = ino_to_fsba(sbp, inode); inum = ino_to_fsbo(sbp, inode); if (debugGetInode) { printf("DEBUG: getting inode 0x%08X\n", inode); printf("DEBUG: this is in fragment %d, inode %d\n", fnum, inum); } readSectors(fnum * spf, spb, ibp); ip = ibp + inum; if (ip->di_size[0] != 0) { halt("File too big"); } if (debugGetInode) { printf("DEBUG: mode of file = 0x%04X\n", ip->di_mode); printf("DEBUG: size of file = 0x%08X\n", ip->di_size[1]); } return ip; } /**************************************************************/ /* convert path to inode */ unsigned int directoryBlock[BSIZE / sizeof(unsigned int)]; Dirent *dbp = (Dirent *) &directoryBlock[0]; Dinode *pathToInode(char *path) { Dinode *ip; char c; char dirBuffer[FFS_MAXNAMLEN]; char *cp; unsigned int offset; Dirent *dp; unsigned int ino; unsigned int len; /* get root inode */ ip = getInode(ROOTINO); /* traverse file system tree while matching path components */ c = *path++; while (1) { /* skip leading slashes in path component */ while (c == '/') { c = *path++; } if (c == '\0') { /* no more path components */ break; } /* if there is another component, gather up its name */ cp = dirBuffer; while (c != '/' && c != '\0') { if (cp < &dirBuffer[FFS_MAXNAMLEN]) { *cp++ = c; } c = *path++; } *cp++ = '\0'; /* ip must be a directory */ if ((ip->di_mode & IFMT) != IFDIR) { return NULL; } if (debugSearchDir) { printf("DEBUG: this is a directory, ok\n"); printf("DEBUG: path component to search for = '%s'\n", dirBuffer); } /* search directory */ offset = 0; while (1) { if (offset >= ip->di_size[1]) { /* component not found */ return NULL; } if ((offset & BMASK) == 0) { /* read the next directory block */ readFileBlock(ip, offset >> BSHIFT, dbp); dp = dbp; } ino = dp->d_fileno; len = dp->d_reclen; if (debugSearchDir) { printf("DEBUG: ino = %4d, len = %4d, ", ino, len); printf("dirsiz = %4d, name = %s\n", DIRSIZ(0, dp, 0), dp->d_name); } if (ino != 0) { if (strcmp(dirBuffer, dp->d_name) == 0) { /* component found */ break; } } /* no match, try next entry */ dp = (Dirent *) ((unsigned char *) dp + len); offset += len; } /* get corresponding inode */ ip = getInode(ino); /* look for more components */ } return ip; } /**************************************************************/ /* load an ELF executable */ #define MAX_PHDR_SIZE 100 Bool loadElf(Dinode *ip, unsigned int *entryPointPtr) { Elf32_Ehdr fileHeader; Elf32_Addr entry; Elf32_Off phoff; Elf32_Half phentsize; Elf32_Half phnum; int i; unsigned int phdrBuf[MAX_PHDR_SIZE / sizeof(unsigned int)]; Elf32_Phdr *phdrPtr; Elf32_Word ptype; Elf32_Off offset; Elf32_Addr address; Elf32_Word filesize; Elf32_Word memsize; Elf32_Word flags; Elf32_Word align; unsigned char *memPtr; int j; readFile(ip, 0, sizeof(Elf32_Ehdr), &fileHeader); if (fileHeader.e_ident[EI_MAG0] != ELFMAG0 || fileHeader.e_ident[EI_MAG1] != ELFMAG1 || fileHeader.e_ident[EI_MAG2] != ELFMAG2 || fileHeader.e_ident[EI_MAG3] != ELFMAG3 || fileHeader.e_ident[EI_CLASS] != ELFCLASS32 || fileHeader.e_ident[EI_DATA] != ELFDATA2MSB || fileHeader.e_type != ET_EXEC || fileHeader.e_machine != EM_ECO32) { /* file is not in ECO32-ELF executable format */ return FALSE; } entry = fileHeader.e_entry; phoff = fileHeader.e_phoff; phentsize = fileHeader.e_phentsize; phnum = fileHeader.e_phnum; if (debugLoadElf) { printf("DEBUG: entry point (virtual addr) : 0x%08X\n", entry); printf("DEBUG: program header table at : %d\n", phoff); printf("DEBUG: prog hdr tbl entry size : %d\n", phentsize); printf("DEBUG: num prog hdr tbl entries : %d\n", phnum); } for (i = 0 ; i < phnum; i++) { printf("Processing program header %d\n", i); readFile(ip, phoff + i * phentsize, phentsize, phdrBuf); phdrPtr = (Elf32_Phdr *) phdrBuf; ptype = phdrPtr->p_type; if (ptype != PT_LOAD) { printf(" type is %u, ignored\n", ptype); continue; } offset = phdrPtr->p_offset; address = phdrPtr->p_vaddr; filesize = phdrPtr->p_filesz; memsize = phdrPtr->p_memsz; flags = phdrPtr->p_flags; align = phdrPtr->p_align; if (debugLoadElf) { printf("DEBUG: offset : 0x%08X bytes\n", offset); printf("DEBUG: address : 0x%08X\n", address); printf("DEBUG: filesize : 0x%08X bytes\n", filesize); printf("DEBUG: memsize : 0x%08X bytes\n", memsize); printf("DEBUG: flags : 0x%08X\n", flags); printf("DEBUG: align : 0x%08X\n", align); } memPtr = (unsigned char *) address; readFile(ip, offset, filesize, memPtr); for (j = filesize; j < memsize; j++) { memPtr[j] = 0; } printf(" segment of %u bytes read", filesize); printf(" (+ %u bytes zeroed)", memsize - filesize); printf(", vaddr = 0x%08X\n", address); } *entryPointPtr = entry; return TRUE; } /**************************************************************/ /* main program */ unsigned int entryPoint; /* where to continue from main() */ int main(void) { char line[MAX_LINE]; Dinode *ip; printf("\n"); printf("NetBSD system loader\n"); readDiskLabel(); readSuperBlock(); strcpy(line, DFLT_KERNEL); while (1) { getLine("\nPlease enter path to kernel: ", line, MAX_LINE); ip = pathToInode(line); if (ip == NULL) { printf("'%s' not found\n", line); continue; } if ((ip->di_mode & IFMT) != IFREG) { printf("'%s' is not a regular file\n", line); continue; } printf("Loading '%s'...\n", line); if (!loadElf(ip, &entryPoint)) { printf("'%s' cannot be loaded\n", line); continue; } /* kernel successfully loaded */ break; } printf("Starting '%s' at address 0x%08X...\n", line, entryPoint); return 0; }
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