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Diffstat (limited to 'bin/dash/src/bltin/test.c')
| -rw-r--r-- | bin/dash/src/bltin/test.c | 700 |
1 files changed, 700 insertions, 0 deletions
diff --git a/bin/dash/src/bltin/test.c b/bin/dash/src/bltin/test.c new file mode 100644 index 00000000..c7fc479d --- /dev/null +++ b/bin/dash/src/bltin/test.c @@ -0,0 +1,700 @@ +/* + * test(1); version 7-like -- author Erik Baalbergen + * modified by Eric Gisin to be used as built-in. + * modified by Arnold Robbins to add SVR3 compatibility + * (-x -c -b -p -u -g -k) plus Korn's -L -nt -ot -ef and new -S (socket). + * modified by J.T. Conklin for NetBSD. + * + * This program is in the Public Domain. + */ + +#include <sys/stat.h> +#include <sys/types.h> + +#include <fcntl.h> +#include <inttypes.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <stdarg.h> +#include "bltin.h" + +/* test(1) accepts the following grammar: + oexpr ::= aexpr | aexpr "-o" oexpr ; + aexpr ::= nexpr | nexpr "-a" aexpr ; + nexpr ::= primary | "!" primary + primary ::= unary-operator operand + | operand binary-operator operand + | operand + | "(" oexpr ")" + ; + unary-operator ::= "-r"|"-w"|"-x"|"-f"|"-d"|"-c"|"-b"|"-p"| + "-u"|"-g"|"-k"|"-s"|"-t"|"-z"|"-n"|"-o"|"-O"|"-G"|"-L"|"-S"; + + binary-operator ::= "="|"!="|"-eq"|"-ne"|"-ge"|"-gt"|"-le"|"-lt"| + "-nt"|"-ot"|"-ef"; + operand ::= <any legal UNIX file name> +*/ + +enum token { + EOI, + FILRD, + FILWR, + FILEX, + FILEXIST, + FILREG, + FILDIR, + FILCDEV, + FILBDEV, + FILFIFO, + FILSOCK, + FILSYM, + FILGZ, + FILTT, + FILSUID, + FILSGID, + FILSTCK, + FILNT, + FILOT, + FILEQ, + FILUID, + FILGID, + STREZ, + STRNZ, + STREQ, + STRNE, + STRLT, + STRGT, + INTEQ, + INTNE, + INTGE, + INTGT, + INTLE, + INTLT, + UNOT, + BAND, + BOR, + LPAREN, + RPAREN, + OPERAND +}; + +enum token_types { + UNOP, + BINOP, + BUNOP, + BBINOP, + PAREN +}; + +static struct t_op { + const char *op_text; + short op_num, op_type; +} const ops [] = { + {"-r", FILRD, UNOP}, + {"-w", FILWR, UNOP}, + {"-x", FILEX, UNOP}, + {"-e", FILEXIST,UNOP}, + {"-f", FILREG, UNOP}, + {"-d", FILDIR, UNOP}, + {"-c", FILCDEV,UNOP}, + {"-b", FILBDEV,UNOP}, + {"-p", FILFIFO,UNOP}, + {"-u", FILSUID,UNOP}, + {"-g", FILSGID,UNOP}, + {"-k", FILSTCK,UNOP}, + {"-s", FILGZ, UNOP}, + {"-t", FILTT, UNOP}, + {"-z", STREZ, UNOP}, + {"-n", STRNZ, UNOP}, + {"-h", FILSYM, UNOP}, /* for backwards compat */ + {"-O", FILUID, UNOP}, + {"-G", FILGID, UNOP}, + {"-L", FILSYM, UNOP}, + {"-S", FILSOCK,UNOP}, + {"=", STREQ, BINOP}, + {"!=", STRNE, BINOP}, + {"<", STRLT, BINOP}, + {">", STRGT, BINOP}, + {"-eq", INTEQ, BINOP}, + {"-ne", INTNE, BINOP}, + {"-ge", INTGE, BINOP}, + {"-gt", INTGT, BINOP}, + {"-le", INTLE, BINOP}, + {"-lt", INTLT, BINOP}, + {"-nt", FILNT, BINOP}, + {"-ot", FILOT, BINOP}, + {"-ef", FILEQ, BINOP}, + {"!", UNOT, BUNOP}, + {"-a", BAND, BBINOP}, + {"-o", BOR, BBINOP}, + {"(", LPAREN, PAREN}, + {")", RPAREN, PAREN}, + {0, 0, 0} +}; + +static char **t_wp; +static struct t_op const *t_wp_op; + +static void syntax(const char *, const char *); +static int oexpr(enum token); +static int aexpr(enum token); +static int nexpr(enum token); +static int primary(enum token); +static int binop(void); +static int filstat(char *, enum token); +static enum token t_lex(char **); +static int isoperand(char **); +static int newerf(const char *, const char *); +static int olderf(const char *, const char *); +static int equalf(const char *, const char *); +#ifdef HAVE_FACCESSAT +static int test_file_access(const char *, int); +#else +static int test_access(const struct stat64 *, int); +#endif + +#ifdef HAVE_FACCESSAT +# ifdef HAVE_TRADITIONAL_FACCESSAT +static inline int faccessat_confused_about_superuser(void) { return 1; } +# else +static inline int faccessat_confused_about_superuser(void) { return 0; } +# endif +#endif + +static inline intmax_t getn(const char *s) +{ + return atomax10(s); +} + +static const struct t_op *getop(const char *s) +{ + const struct t_op *op; + + for (op = ops; op->op_text; op++) { + if (strcmp(s, op->op_text) == 0) + return op; + } + + return NULL; +} + +int +testcmd(int argc, char **argv) +{ + const struct t_op *op; + enum token n; + int res = 1; + + if (*argv[0] == '[') { + if (*argv[--argc] != ']') + error("missing ]"); + argv[argc] = NULL; + } + + t_wp_op = NULL; + +recheck: + argv++; + argc--; + + if (argc < 1) + return res; + + /* + * POSIX prescriptions: he who wrote this deserves the Nobel + * peace prize. + */ + switch (argc) { + case 3: + op = getop(argv[1]); + if (op && op->op_type == BINOP) { + n = OPERAND; + goto eval; + } + /* fall through */ + + case 4: + if (!strcmp(argv[0], "(") && !strcmp(argv[argc - 1], ")")) { + argv[--argc] = NULL; + argv++; + argc--; + } else if (!strcmp(argv[0], "!")) { + res = 0; + goto recheck; + } + } + + n = t_lex(argv); + +eval: + t_wp = argv; + res ^= oexpr(n); + argv = t_wp; + + if (argv[0] != NULL && argv[1] != NULL) + syntax(argv[0], "unexpected operator"); + + return res; +} + +static void +syntax(const char *op, const char *msg) +{ + if (op && *op) + error("%s: %s", op, msg); + else + error("%s", msg); +} + +static int +oexpr(enum token n) +{ + int res = 0; + + for (;;) { + res |= aexpr(n); + n = t_lex(t_wp + 1); + if (n != BOR) + break; + n = t_lex(t_wp += 2); + } + return res; +} + +static int +aexpr(enum token n) +{ + int res = 1; + + for (;;) { + if (!nexpr(n)) + res = 0; + n = t_lex(t_wp + 1); + if (n != BAND) + break; + n = t_lex(t_wp += 2); + } + return res; +} + +static int +nexpr(enum token n) +{ + if (n != UNOT) + return primary(n); + + n = t_lex(t_wp + 1); + if (n != EOI) + t_wp++; + return !nexpr(n); +} + +static int +primary(enum token n) +{ + enum token nn; + int res; + + if (n == EOI) + return 0; /* missing expression */ + if (n == LPAREN) { + if ((nn = t_lex(++t_wp)) == RPAREN) + return 0; /* missing expression */ + res = oexpr(nn); + if (t_lex(++t_wp) != RPAREN) + syntax(NULL, "closing paren expected"); + return res; + } + if (t_wp_op && t_wp_op->op_type == UNOP) { + /* unary expression */ + if (*++t_wp == NULL) + syntax(t_wp_op->op_text, "argument expected"); + switch (n) { + case STREZ: + return strlen(*t_wp) == 0; + case STRNZ: + return strlen(*t_wp) != 0; + case FILTT: + return isatty(getn(*t_wp)); +#ifdef HAVE_FACCESSAT + case FILRD: + return test_file_access(*t_wp, R_OK); + case FILWR: + return test_file_access(*t_wp, W_OK); + case FILEX: + return test_file_access(*t_wp, X_OK); +#endif + default: + return filstat(*t_wp, n); + } + } + + if (t_lex(t_wp + 1), t_wp_op && t_wp_op->op_type == BINOP) { + return binop(); + } + + return strlen(*t_wp) > 0; +} + +static int +binop(void) +{ + const char *opnd1, *opnd2; + struct t_op const *op; + + opnd1 = *t_wp; + (void) t_lex(++t_wp); + op = t_wp_op; + + if ((opnd2 = *++t_wp) == (char *)0) + syntax(op->op_text, "argument expected"); + + switch (op->op_num) { + default: +#ifdef DEBUG + abort(); + /* NOTREACHED */ +#endif + case STREQ: + return strcmp(opnd1, opnd2) == 0; + case STRNE: + return strcmp(opnd1, opnd2) != 0; + case STRLT: + return strcmp(opnd1, opnd2) < 0; + case STRGT: + return strcmp(opnd1, opnd2) > 0; + case INTEQ: + return getn(opnd1) == getn(opnd2); + case INTNE: + return getn(opnd1) != getn(opnd2); + case INTGE: + return getn(opnd1) >= getn(opnd2); + case INTGT: + return getn(opnd1) > getn(opnd2); + case INTLE: + return getn(opnd1) <= getn(opnd2); + case INTLT: + return getn(opnd1) < getn(opnd2); + case FILNT: + return newerf (opnd1, opnd2); + case FILOT: + return olderf (opnd1, opnd2); + case FILEQ: + return equalf (opnd1, opnd2); + } +} + +static int +filstat(char *nm, enum token mode) +{ + struct stat64 s; + + if (mode == FILSYM ? lstat64(nm, &s) : stat64(nm, &s)) + return 0; + + switch (mode) { +#ifndef HAVE_FACCESSAT + case FILRD: + return test_access(&s, R_OK); + case FILWR: + return test_access(&s, W_OK); + case FILEX: + return test_access(&s, X_OK); +#endif + case FILEXIST: + return 1; + case FILREG: + return S_ISREG(s.st_mode); + case FILDIR: + return S_ISDIR(s.st_mode); + case FILCDEV: + return S_ISCHR(s.st_mode); + case FILBDEV: + return S_ISBLK(s.st_mode); + case FILFIFO: + return S_ISFIFO(s.st_mode); + case FILSOCK: + return S_ISSOCK(s.st_mode); + case FILSYM: + return S_ISLNK(s.st_mode); + case FILSUID: + return (s.st_mode & S_ISUID) != 0; + case FILSGID: + return (s.st_mode & S_ISGID) != 0; + case FILSTCK: + return (s.st_mode & S_ISVTX) != 0; + case FILGZ: + return !!s.st_size; + case FILUID: + return s.st_uid == geteuid(); + case FILGID: + return s.st_gid == getegid(); + default: + return 1; + } +} + +static enum token t_lex(char **tp) +{ + struct t_op const *op; + char *s = *tp; + + if (s == 0) { + t_wp_op = (struct t_op *)0; + return EOI; + } + + op = getop(s); + if (op && !(op->op_type == UNOP && isoperand(tp)) && + !(op->op_num == LPAREN && !tp[1])) { + t_wp_op = op; + return op->op_num; + } + + t_wp_op = (struct t_op *)0; + return OPERAND; +} + +static int isoperand(char **tp) +{ + struct t_op const *op; + char *s; + + if (!(s = tp[1])) + return 1; + if (!tp[2]) + return 0; + + op = getop(s); + return op && op->op_type == BINOP; +} + +static int +newerf (const char *f1, const char *f2) +{ + struct stat64 b1, b2; + +#ifdef HAVE_ST_MTIM + return (stat64(f1, &b1) == 0 && + stat64(f2, &b2) == 0 && + ( b1.st_mtim.tv_sec > b2.st_mtim.tv_sec || + (b1.st_mtim.tv_sec == b2.st_mtim.tv_sec && (b1.st_mtim.tv_nsec > b2.st_mtim.tv_nsec ))) + ); +#else + return (stat64(f1, &b1) == 0 && + stat64(f2, &b2) == 0 && + b1.st_mtime > b2.st_mtime); +#endif +} + +static int +olderf (const char *f1, const char *f2) +{ + struct stat64 b1, b2; + +#ifdef HAVE_ST_MTIM + return (stat64(f1, &b1) == 0 && + stat64(f2, &b2) == 0 && + (b1.st_mtim.tv_sec < b2.st_mtim.tv_sec || + (b1.st_mtim.tv_sec == b2.st_mtim.tv_sec && (b1.st_mtim.tv_nsec < b2.st_mtim.tv_nsec ))) + ); +#else + return (stat64(f1, &b1) == 0 && + stat64(f2, &b2) == 0 && + b1.st_mtime < b2.st_mtime); +#endif +} + +static int +equalf (const char *f1, const char *f2) +{ + struct stat64 b1, b2; + + return (stat64(f1, &b1) == 0 && + stat64(f2, &b2) == 0 && + b1.st_dev == b2.st_dev && + b1.st_ino == b2.st_ino); +} + +#ifdef HAVE_FACCESSAT +static int has_exec_bit_set(const char *path) +{ + struct stat64 st; + + if (stat64(path, &st)) + return 0; + return st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH); +} + +static int test_file_access(const char *path, int mode) +{ + if (faccessat_confused_about_superuser() && + mode == X_OK && geteuid() == 0 && !has_exec_bit_set(path)) + return 0; + return !faccessat(AT_FDCWD, path, mode, AT_EACCESS); +} +#else /* HAVE_FACCESSAT */ +/* + * The manual, and IEEE POSIX 1003.2, suggests this should check the mode bits, + * not use access(): + * + * True shall indicate only that the write flag is on. The file is not + * writable on a read-only file system even if this test indicates true. + * + * Unfortunately IEEE POSIX 1003.1-2001, as quoted in SuSv3, says only: + * + * True shall indicate that permission to read from file will be granted, + * as defined in "File Read, Write, and Creation". + * + * and that section says: + * + * When a file is to be read or written, the file shall be opened with an + * access mode corresponding to the operation to be performed. If file + * access permissions deny access, the requested operation shall fail. + * + * and of course access permissions are described as one might expect: + * + * * If a process has the appropriate privilege: + * + * * If read, write, or directory search permission is requested, + * access shall be granted. + * + * * If execute permission is requested, access shall be granted if + * execute permission is granted to at least one user by the file + * permission bits or by an alternate access control mechanism; + * otherwise, access shall be denied. + * + * * Otherwise: + * + * * The file permission bits of a file contain read, write, and + * execute/search permissions for the file owner class, file group + * class, and file other class. + * + * * Access shall be granted if an alternate access control mechanism + * is not enabled and the requested access permission bit is set for + * the class (file owner class, file group class, or file other class) + * to which the process belongs, or if an alternate access control + * mechanism is enabled and it allows the requested access; otherwise, + * access shall be denied. + * + * and when I first read this I thought: surely we can't go about using + * open(O_WRONLY) to try this test! However the POSIX 1003.1-2001 Rationale + * section for test does in fact say: + * + * On historical BSD systems, test -w directory always returned false + * because test tried to open the directory for writing, which always + * fails. + * + * and indeed this is in fact true for Seventh Edition UNIX, UNIX 32V, and UNIX + * System III, and thus presumably also for BSD up to and including 4.3. + * + * Secondly I remembered why using open() and/or access() are bogus. They + * don't work right for detecting read and write permissions bits when called + * by root. + * + * Interestingly the 'test' in 4.4BSD was closer to correct (as per + * 1003.2-1992) and it was implemented efficiently with stat() instead of + * open(). + * + * This was apparently broken in NetBSD around about 1994/06/30 when the old + * 4.4BSD implementation was replaced with a (arguably much better coded) + * implementation derived from pdksh. + * + * Note that modern pdksh is yet different again, but still not correct, at + * least not w.r.t. 1003.2-1992. + * + * As I think more about it and read more of the related IEEE docs I don't like + * that wording about 'test -r' and 'test -w' in 1003.1-2001 at all. I very + * much prefer the original wording in 1003.2-1992. It is much more useful, + * and so that's what I've implemented. + * + * (Note that a strictly conforming implementation of 1003.1-2001 is in fact + * totally useless for the case in question since its 'test -w' and 'test -r' + * can never fail for root for any existing files, i.e. files for which 'test + * -e' succeeds.) + * + * The rationale for 1003.1-2001 suggests that the wording was "clarified" in + * 1003.1-2001 to align with the 1003.2b draft. 1003.2b Draft 12 (July 1999), + * which is the latest copy I have, does carry the same suggested wording as is + * in 1003.1-2001, with its rationale saying: + * + * This change is a clarification and is the result of interpretation + * request PASC 1003.2-92 #23 submitted for IEEE Std 1003.2-1992. + * + * That interpretation can be found here: + * + * http://www.pasc.org/interps/unofficial/db/p1003.2/pasc-1003.2-23.html + * + * Not terribly helpful, unfortunately. I wonder who that fence sitter was. + * + * Worse, IMVNSHO, I think the authors of 1003.2b-D12 have mis-interpreted the + * PASC interpretation and appear to be gone against at least one widely used + * implementation (namely 4.4BSD). The problem is that for file access by root + * this means that if test '-r' and '-w' are to behave as if open() were called + * then there's no way for a shell script running as root to check if a file + * has certain access bits set other than by the grotty means of interpreting + * the output of 'ls -l'. This was widely considered to be a bug in V7's + * "test" and is, I believe, one of the reasons why direct use of access() was + * avoided in some more recent implementations! + * + * I have always interpreted '-r' to match '-w' and '-x' as per the original + * wording in 1003.2-1992, not the other way around. I think 1003.2b goes much + * too far the wrong way without any valid rationale and that it's best if we + * stick with 1003.2-1992 and test the flags, and not mimic the behaviour of + * open() since we already know very well how it will work -- existance of the + * file is all that matters to open() for root. + * + * Unfortunately the SVID is no help at all (which is, I guess, partly why + * we're in this mess in the first place :-). + * + * The SysV implementation (at least in the 'test' builtin in /bin/sh) does use + * access(name, 2) even though it also goes to much greater lengths for '-x' + * matching the 1003.2-1992 definition (which is no doubt where that definition + * came from). + * + * The ksh93 implementation uses access() for '-r' and '-w' if + * (euid==uid&&egid==gid), but uses st_mode for '-x' iff running as root. + * i.e. it does strictly conform to 1003.1-2001 (and presumably 1003.2b). + */ +static int test_access(const struct stat64 *sp, int stmode) +{ + gid_t *groups; + register int n; + uid_t euid; + int maxgroups; + + /* + * I suppose we could use access() if not running as root and if we are + * running with ((euid == uid) && (egid == gid)), but we've already + * done the stat() so we might as well just test the permissions + * directly instead of asking the kernel to do it.... + */ + euid = geteuid(); + if (euid == 0) { + if (stmode != X_OK) + return 1; + + /* any bit is good enough */ + stmode = (stmode << 6) | (stmode << 3) | stmode; + } else if (sp->st_uid == euid) + stmode <<= 6; + else if (sp->st_gid == getegid()) + stmode <<= 3; + else { + /* XXX stolen almost verbatim from ksh93.... */ + /* on some systems you can be in several groups */ + maxgroups = getgroups(0, NULL); + groups = stalloc(maxgroups * sizeof(*groups)); + n = getgroups(maxgroups, groups); + while (--n >= 0) { + if (groups[n] == sp->st_gid) { + stmode <<= 3; + break; + } + } + } + + return sp->st_mode & stmode; +} +#endif /* HAVE_FACCESSAT */ |