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Diffstat (limited to 'bin/1sh/exec.c')
| -rw-r--r-- | bin/1sh/exec.c | 784 |
1 files changed, 784 insertions, 0 deletions
diff --git a/bin/1sh/exec.c b/bin/1sh/exec.c new file mode 100644 index 00000000..5026e644 --- /dev/null +++ b/bin/1sh/exec.c @@ -0,0 +1,784 @@ +/*- + * Copyright (c) 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Kenneth Almquist. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef lint +#if 0 +static char sccsid[] = "@(#)exec.c 8.4 (Berkeley) 6/8/95"; +#endif +#endif /* not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD: releng/12.0/bin/sh/exec.c 336320 2018-07-15 21:55:17Z jilles $"); + +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> +#include <fcntl.h> +#include <errno.h> +#include <paths.h> +#include <stdlib.h> + +/* + * When commands are first encountered, they are entered in a hash table. + * This ensures that a full path search will not have to be done for them + * on each invocation. + * + * We should investigate converting to a linear search, even though that + * would make the command name "hash" a misnomer. + */ + +#include "shell.h" +#include "main.h" +#include "nodes.h" +#include "parser.h" +#include "redir.h" +#include "eval.h" +#include "exec.h" +#include "builtins.h" +#include "var.h" +#include "options.h" +#include "input.h" +#include "output.h" +#include "syntax.h" +#include "memalloc.h" +#include "error.h" +#include "mystring.h" +#include "show.h" +#include "jobs.h" +#include "alias.h" + + +#define CMDTABLESIZE 31 /* should be prime */ + + + +struct tblentry { + struct tblentry *next; /* next entry in hash chain */ + union param param; /* definition of builtin function */ + int special; /* flag for special builtin commands */ + signed char cmdtype; /* index identifying command */ + char cmdname[]; /* name of command */ +}; + + +static struct tblentry *cmdtable[CMDTABLESIZE]; +static int cmdtable_cd = 0; /* cmdtable contains cd-dependent entries */ +int exerrno = 0; /* Last exec error */ + + +static void tryexec(char *, char **, char **); +static void printentry(struct tblentry *, int); +static struct tblentry *cmdlookup(const char *, int); +static void delete_cmd_entry(void); +static void addcmdentry(const char *, struct cmdentry *); + + + +/* + * Exec a program. Never returns. If you change this routine, you may + * have to change the find_command routine as well. + * + * The argv array may be changed and element argv[-1] should be writable. + */ + +void +shellexec(char **argv, char **envp, const char *path, int idx) +{ + char *cmdname; + const char *opt; + int e; + + if (strchr(argv[0], '/') != NULL) { + tryexec(argv[0], argv, envp); + e = errno; + } else { + e = ENOENT; + while ((cmdname = padvance(&path, &opt, argv[0])) != NULL) { + if (--idx < 0 && opt == NULL) { + tryexec(cmdname, argv, envp); + if (errno != ENOENT && errno != ENOTDIR) + e = errno; + if (e == ENOEXEC) + break; + } + stunalloc(cmdname); + } + } + + /* Map to POSIX errors */ + if (e == ENOENT || e == ENOTDIR) { + exerrno = 127; + exerror(EXEXEC, "%s: not found", argv[0]); + } else { + exerrno = 126; + exerror(EXEXEC, "%s: %s", argv[0], strerror(e)); + } +} + + +static void +tryexec(char *cmd, char **argv, char **envp) +{ + int e, in; + ssize_t n; + char buf[256]; + + execve(cmd, argv, envp); + e = errno; + if (e == ENOEXEC) { + INTOFF; + in = open(cmd, O_RDONLY | O_NONBLOCK); + if (in != -1) { + n = pread(in, buf, sizeof buf, 0); + close(in); + if (n > 0 && memchr(buf, '\0', n) != NULL) { + errno = ENOEXEC; + return; + } + } + *argv = cmd; + *--argv = __DECONST(char *, _PATH_BSHELL); + execve(_PATH_BSHELL, argv, envp); + } + errno = e; +} + +/* + * Do a path search. The variable path (passed by reference) should be + * set to the start of the path before the first call; padvance will update + * this value as it proceeds. Successive calls to padvance will return + * the possible path expansions in sequence. If popt is not NULL, options + * are processed: if an option (indicated by a percent sign) appears in + * the path entry then *popt will be set to point to it; else *popt will be + * set to NULL. If popt is NULL, percent signs are not special. + */ + +char * +padvance(const char **path, const char **popt, const char *name) +{ + const char *p, *start; + char *q; + size_t len, namelen; + + if (*path == NULL) + return NULL; + start = *path; + if (popt != NULL) + for (p = start; *p && *p != ':' && *p != '%'; p++) + ; /* nothing */ + else + for (p = start; *p && *p != ':'; p++) + ; /* nothing */ + namelen = strlen(name); + len = p - start + namelen + 2; /* "2" is for '/' and '\0' */ + STARTSTACKSTR(q); + CHECKSTRSPACE(len, q); + if (p != start) { + memcpy(q, start, p - start); + q += p - start; + *q++ = '/'; + } + memcpy(q, name, namelen + 1); + if (popt != NULL) { + if (*p == '%') { + *popt = ++p; + while (*p && *p != ':') p++; + } else + *popt = NULL; + } + if (*p == ':') + *path = p + 1; + else + *path = NULL; + return stalloc(len); +} + + + +/*** Command hashing code ***/ + + +int +hashcmd(int argc __unused, char **argv __unused) +{ + struct tblentry **pp; + struct tblentry *cmdp; + int c; + int verbose; + struct cmdentry entry; + char *name; + int errors; + + errors = 0; + verbose = 0; + while ((c = nextopt("rv")) != '\0') { + if (c == 'r') { + clearcmdentry(); + } else if (c == 'v') { + verbose++; + } + } + if (*argptr == NULL) { + for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { + for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { + if (cmdp->cmdtype == CMDNORMAL) + printentry(cmdp, verbose); + } + } + return 0; + } + while ((name = *argptr) != NULL) { + if ((cmdp = cmdlookup(name, 0)) != NULL + && cmdp->cmdtype == CMDNORMAL) + delete_cmd_entry(); + find_command(name, &entry, DO_ERR, pathval()); + if (entry.cmdtype == CMDUNKNOWN) + errors = 1; + else if (verbose) { + cmdp = cmdlookup(name, 0); + if (cmdp != NULL) + printentry(cmdp, verbose); + else { + outfmt(out2, "%s: not found\n", name); + errors = 1; + } + flushall(); + } + argptr++; + } + return errors; +} + + +static void +printentry(struct tblentry *cmdp, int verbose) +{ + int idx; + const char *path, *opt; + char *name; + + if (cmdp->cmdtype == CMDNORMAL) { + idx = cmdp->param.index; + path = pathval(); + do { + name = padvance(&path, &opt, cmdp->cmdname); + stunalloc(name); + } while (--idx >= 0); + out1str(name); + } else if (cmdp->cmdtype == CMDBUILTIN) { + out1fmt("builtin %s", cmdp->cmdname); + } else if (cmdp->cmdtype == CMDFUNCTION) { + out1fmt("function %s", cmdp->cmdname); + if (verbose) { + INTOFF; + name = commandtext(getfuncnode(cmdp->param.func)); + out1c(' '); + out1str(name); + ckfree(name); + INTON; + } +#ifdef DEBUG + } else { + error("internal error: cmdtype %d", cmdp->cmdtype); +#endif + } + out1c('\n'); +} + + + +/* + * Resolve a command name. If you change this routine, you may have to + * change the shellexec routine as well. + */ + +void +find_command(const char *name, struct cmdentry *entry, int act, + const char *path) +{ + struct tblentry *cmdp, loc_cmd; + int idx; + const char *opt; + char *fullname; + struct stat statb; + int e; + int i; + int spec; + int cd; + + /* If name contains a slash, don't use the hash table */ + if (strchr(name, '/') != NULL) { + entry->cmdtype = CMDNORMAL; + entry->u.index = 0; + entry->special = 0; + return; + } + + cd = 0; + + /* If name is in the table, we're done */ + if ((cmdp = cmdlookup(name, 0)) != NULL) { + if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC) + cmdp = NULL; + else + goto success; + } + + /* Check for builtin next */ + if ((i = find_builtin(name, &spec)) >= 0) { + INTOFF; + cmdp = cmdlookup(name, 1); + if (cmdp->cmdtype == CMDFUNCTION) + cmdp = &loc_cmd; + cmdp->cmdtype = CMDBUILTIN; + cmdp->param.index = i; + cmdp->special = spec; + INTON; + goto success; + } + + /* We have to search path. */ + + e = ENOENT; + idx = -1; + for (;(fullname = padvance(&path, &opt, name)) != NULL; + stunalloc(fullname)) { + idx++; + if (opt) { + if (strncmp(opt, "func", 4) == 0) { + /* handled below */ + } else { + continue; /* ignore unimplemented options */ + } + } + if (fullname[0] != '/') + cd = 1; + if (stat(fullname, &statb) < 0) { + if (errno != ENOENT && errno != ENOTDIR) + e = errno; + continue; + } + e = EACCES; /* if we fail, this will be the error */ + if (!S_ISREG(statb.st_mode)) + continue; + if (opt) { /* this is a %func directory */ + readcmdfile(fullname); + if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) + error("%s not defined in %s", name, fullname); + stunalloc(fullname); + goto success; + } +#ifdef notdef + if (statb.st_uid == geteuid()) { + if ((statb.st_mode & 0100) == 0) + goto loop; + } else if (statb.st_gid == getegid()) { + if ((statb.st_mode & 010) == 0) + goto loop; + } else { + if ((statb.st_mode & 01) == 0) + goto loop; + } +#endif + TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); + INTOFF; + stunalloc(fullname); + cmdp = cmdlookup(name, 1); + if (cmdp->cmdtype == CMDFUNCTION) + cmdp = &loc_cmd; + cmdp->cmdtype = CMDNORMAL; + cmdp->param.index = idx; + cmdp->special = 0; + INTON; + goto success; + } + + if (act & DO_ERR) { + if (e == ENOENT || e == ENOTDIR) + outfmt(out2, "%s: not found\n", name); + else + outfmt(out2, "%s: %s\n", name, strerror(e)); + } + entry->cmdtype = CMDUNKNOWN; + entry->u.index = 0; + entry->special = 0; + return; + +success: + if (cd) + cmdtable_cd = 1; + entry->cmdtype = cmdp->cmdtype; + entry->u = cmdp->param; + entry->special = cmdp->special; +} + + + +/* + * Search the table of builtin commands. + */ + +int +find_builtin(const char *name, int *special) +{ + const unsigned char *bp; + size_t len; + + len = strlen(name); + for (bp = builtincmd ; *bp ; bp += 2 + bp[0]) { + if (bp[0] == len && memcmp(bp + 2, name, len) == 0) { + *special = (bp[1] & BUILTIN_SPECIAL) != 0; + return bp[1] & ~BUILTIN_SPECIAL; + } + } + return -1; +} + + + +/* + * Called when a cd is done. If any entry in cmdtable depends on the current + * directory, simply clear cmdtable completely. + */ + +void +hashcd(void) +{ + if (cmdtable_cd) + clearcmdentry(); +} + + + +/* + * Called before PATH is changed. The argument is the new value of PATH; + * pathval() still returns the old value at this point. Called with + * interrupts off. + */ + +void +changepath(const char *newval __unused) +{ + clearcmdentry(); +} + + +/* + * Clear out cached utility locations. + */ + +void +clearcmdentry(void) +{ + struct tblentry **tblp; + struct tblentry **pp; + struct tblentry *cmdp; + + INTOFF; + for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { + pp = tblp; + while ((cmdp = *pp) != NULL) { + if (cmdp->cmdtype == CMDNORMAL) { + *pp = cmdp->next; + ckfree(cmdp); + } else { + pp = &cmdp->next; + } + } + } + cmdtable_cd = 0; + INTON; +} + + +/* + * Locate a command in the command hash table. If "add" is nonzero, + * add the command to the table if it is not already present. The + * variable "lastcmdentry" is set to point to the address of the link + * pointing to the entry, so that delete_cmd_entry can delete the + * entry. + */ + +static struct tblentry **lastcmdentry; + + +static struct tblentry * +cmdlookup(const char *name, int add) +{ + unsigned int hashval; + const char *p; + struct tblentry *cmdp; + struct tblentry **pp; + size_t len; + + p = name; + hashval = (unsigned char)*p << 4; + while (*p) + hashval += *p++; + pp = &cmdtable[hashval % CMDTABLESIZE]; + for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { + if (equal(cmdp->cmdname, name)) + break; + pp = &cmdp->next; + } + if (add && cmdp == NULL) { + INTOFF; + len = strlen(name); + cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1); + cmdp->next = NULL; + cmdp->cmdtype = CMDUNKNOWN; + memcpy(cmdp->cmdname, name, len + 1); + INTON; + } + lastcmdentry = pp; + return cmdp; +} + +/* + * Delete the command entry returned on the last lookup. + */ + +static void +delete_cmd_entry(void) +{ + struct tblentry *cmdp; + + INTOFF; + cmdp = *lastcmdentry; + *lastcmdentry = cmdp->next; + ckfree(cmdp); + INTON; +} + + + +/* + * Add a new command entry, replacing any existing command entry for + * the same name. + */ + +static void +addcmdentry(const char *name, struct cmdentry *entry) +{ + struct tblentry *cmdp; + + INTOFF; + cmdp = cmdlookup(name, 1); + if (cmdp->cmdtype == CMDFUNCTION) { + unreffunc(cmdp->param.func); + } + cmdp->cmdtype = entry->cmdtype; + cmdp->param = entry->u; + cmdp->special = entry->special; + INTON; +} + + +/* + * Define a shell function. + */ + +void +defun(const char *name, union node *func) +{ + struct cmdentry entry; + + INTOFF; + entry.cmdtype = CMDFUNCTION; + entry.u.func = copyfunc(func); + entry.special = 0; + addcmdentry(name, &entry); + INTON; +} + + +/* + * Delete a function if it exists. + * Called with interrupts off. + */ + +int +unsetfunc(const char *name) +{ + struct tblentry *cmdp; + + if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { + unreffunc(cmdp->param.func); + delete_cmd_entry(); + return (0); + } + return (0); +} + + +/* + * Check if a function by a certain name exists. + */ +int +isfunc(const char *name) +{ + struct tblentry *cmdp; + cmdp = cmdlookup(name, 0); + return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION); +} + + +/* + * Shared code for the following builtin commands: + * type, command -v, command -V + */ + +int +typecmd_impl(int argc, char **argv, int cmd, const char *path) +{ + struct cmdentry entry; + struct tblentry *cmdp; + const char *const *pp; + struct alias *ap; + int i; + int error1 = 0; + + if (path != pathval()) + clearcmdentry(); + + for (i = 1; i < argc; i++) { + /* First look at the keywords */ + for (pp = parsekwd; *pp; pp++) + if (**pp == *argv[i] && equal(*pp, argv[i])) + break; + + if (*pp) { + if (cmd == TYPECMD_SMALLV) + out1fmt("%s\n", argv[i]); + else + out1fmt("%s is a shell keyword\n", argv[i]); + continue; + } + + /* Then look at the aliases */ + if ((ap = lookupalias(argv[i], 1)) != NULL) { + if (cmd == TYPECMD_SMALLV) { + out1fmt("alias %s=", argv[i]); + out1qstr(ap->val); + outcslow('\n', out1); + } else + out1fmt("%s is an alias for %s\n", argv[i], + ap->val); + continue; + } + + /* Then check if it is a tracked alias */ + if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { + entry.cmdtype = cmdp->cmdtype; + entry.u = cmdp->param; + entry.special = cmdp->special; + } + else { + /* Finally use brute force */ + find_command(argv[i], &entry, 0, path); + } + + switch (entry.cmdtype) { + case CMDNORMAL: { + if (strchr(argv[i], '/') == NULL) { + const char *path2 = path; + const char *opt2; + char *name; + int j = entry.u.index; + do { + name = padvance(&path2, &opt2, argv[i]); + stunalloc(name); + } while (--j >= 0); + if (cmd == TYPECMD_SMALLV) + out1fmt("%s\n", name); + else + out1fmt("%s is%s %s\n", argv[i], + (cmdp && cmd == TYPECMD_TYPE) ? + " a tracked alias for" : "", + name); + } else { + if (faccessat(AT_FDCWD, argv[i], X_OK, AT_EACCESS) == 0) { + if (cmd == TYPECMD_SMALLV) + out1fmt("%s\n", argv[i]); + else + out1fmt("%s is %s\n", argv[i], + argv[i]); + } else { + if (cmd != TYPECMD_SMALLV) + outfmt(out2, "%s: %s\n", + argv[i], strerror(errno)); + error1 |= 127; + } + } + break; + } + case CMDFUNCTION: + if (cmd == TYPECMD_SMALLV) + out1fmt("%s\n", argv[i]); + else + out1fmt("%s is a shell function\n", argv[i]); + break; + + case CMDBUILTIN: + if (cmd == TYPECMD_SMALLV) + out1fmt("%s\n", argv[i]); + else if (entry.special) + out1fmt("%s is a special shell builtin\n", + argv[i]); + else + out1fmt("%s is a shell builtin\n", argv[i]); + break; + + default: + if (cmd != TYPECMD_SMALLV) + outfmt(out2, "%s: not found\n", argv[i]); + error1 |= 127; + break; + } + } + + if (path != pathval()) + clearcmdentry(); + + return error1; +} + +/* + * Locate and print what a word is... + */ + +int +typecmd(int argc, char **argv) +{ + if (argc > 2 && strcmp(argv[1], "--") == 0) + argc--, argv++; + return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1)); +} |