diff options
Diffstat (limited to 'toys/posix')
| -rw-r--r-- | toys/posix/sh.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/toys/posix/sh.c b/toys/posix/sh.c new file mode 100644 index 00000000..d26eb44b --- /dev/null +++ b/toys/posix/sh.c @@ -0,0 +1,390 @@ +/* vi: set sw=4 ts=4: + * + * sh.c - toybox shell + * + * Copyright 2006 Rob Landley <rob@landley.net> + * + * The POSIX-2008/SUSv4 spec for this is at: + * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html + * and http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html + * + * The first link describes the following shell builtins: + * + * break colon continue dot eval exec exit export readonly return set shift + * times trap unset + * + * The second link (the utilities directory) also contains specs for the + * following shell builtins: + * + * alias bg cd command fc fg getopts hash jobs kill read type ulimit + * umask unalias wait + * + * Things like the bash man page are good to read too. + * + * TODO: // Handle embedded NUL bytes in the command line. + +USE_SH(NEWTOY(cd, NULL, TOYFLAG_NOFORK)) +USE_SH(NEWTOY(exit, NULL, TOYFLAG_NOFORK)) + +USE_SH(NEWTOY(sh, "c:i", TOYFLAG_BIN)) +USE_SH(OLDTOY(toysh, sh, "c:i", TOYFLAG_BIN)) + +config SH + bool "sh (toysh)" + default n + help + usage: sh [-c command] [script] + + Command shell. Runs a shell script, or reads input interactively + and responds to it. + + -c command line to execute + +config SH_TTY + bool "Interactive shell (terminal control)" + default n + depends on SH + help + Add terminal control to toysh. This is necessary for interactive use, + so the shell isn't killed by CTRL-C. + +config SH_PROFILE + bool "Profile support" + default n + depends on SH_TTY + help + Read /etc/profile and ~/.profile when running interactively. + + Also enables the built-in command "source". + +config SH_JOBCTL + bool "Job Control (fg, bg, jobs)" + default n + depends on SH_TTY + help + Add job control to toysh. This lets toysh handle CTRL-Z, and enables + the built-in commands "fg", "bg", and "jobs". + + With pipe support, enable use of "&" to run background processes. + +config SH_FLOWCTL + bool "Flow control (if, while, for, functions)" + default n + depends on SH + help + Add flow control to toysh. This enables the if/then/else/fi, + while/do/done, and for/do/done constructs. + + With pipe support, this enables the ability to define functions + using the "function name" or "name()" syntax, plus curly brackets + "{ }" to group commands. + +config SH_QUOTES + bool "Smarter argument parsing (quotes)" + default n + depends on SH + help + Add support for parsing "" and '' style quotes to the toysh command + parser, with lets arguments have spaces in them. + +config SH_WILDCARDS + bool "Wildcards ( ?*{,} )" + default n + depends on SH_QUOTES + help + Expand wildcards in argument names, ala "ls -l *.t?z" and + "rm subdir/{one,two,three}.txt". + +config SH_PROCARGS + bool "Executable arguments ( `` and $() )" + default n + depends on SH_QUOTES + help + Add support for executing arguments contianing $() and ``, using + the output of the command as the new argument value(s). + + (Bash calls this "command substitution".) + +config SH_ENVVARS + bool "Environment variable support" + default n + depends on SH_QUOTES + help + Substitute environment variable values for $VARNAME or ${VARNAME}, + and enable the built-in command "export". + +config SH_LOCALS + bool "Local variables" + default n + depends on SH_ENVVARS + help + Support for local variables, fancy prompts ($PS1), the "set" command, + and $?. + +config SH_ARRAYS + bool "Array variables" + default n + depends on SH_LOCALS + help + Support for ${blah[blah]} style array variables. + +config SH_PIPES + bool "Pipes and redirects ( | > >> < << & && | || () ; )" + default n + depends on SH + help + Support multiple commands on the same command line. This includes + | pipes, > >> < redirects, << here documents, || && conditional + execution, () subshells, ; sequential execution, and (with job + control) & background processes. + +config SH_BUILTINS + bool "Builtin commands" + default n + depends on SH + help + Adds the commands exec, fg, bg, help, jobs, pwd, export, source, set, + unset, read, alias. + +config EXIT + bool + default n + depends on SH + help + usage: exit [status] + + Exit shell. If no return value supplied on command line, use value + of most recent command, or 0 if none. + +config CD + bool + default n + depends on SH + help + usage: cd [path] + + Change current directory. With no arguments, go to $HOME. + +config CD_P + bool # "-P support for cd" + default n + depends on SH + help + usage: cd [-PL] + + -P Physical path: resolve symlinks in path. + -L Cancel previous -P and restore default behavior. +*/ + +#include "toys.h" + +DEFINE_GLOBALS( + char *command; +) + +#define TT this.sh + +// A single executable, its arguments, and other information we know about it. +#define TOYSH_FLAG_EXIT 1 +#define TOYSH_FLAG_SUSPEND 2 +#define TOYSH_FLAG_PIPE 4 +#define TOYSH_FLAG_AND 8 +#define TOYSH_FLAG_OR 16 +#define TOYSH_FLAG_AMP 32 +#define TOYSH_FLAG_SEMI 64 +#define TOYSH_FLAG_PAREN 128 + +// What we know about a single process. +struct command { + struct command *next; + int flags; // exit, suspend, && || + int pid; // pid (or exit code) + int argc; + char *argv[0]; +}; + +// A collection of processes piped into/waiting on each other. +struct pipeline { + struct pipeline *next; + int job_id; + struct command *cmd; + char *cmdline; // Unparsed line for display purposes + int cmdlinelen; // How long is cmdline? +}; + +// Parse one word from the command line, appending one or more argv[] entries +// to struct command. Handles environment variable substitution and +// substrings. Returns pointer to next used byte, or NULL if it +// hit an ending token. +static char *parse_word(char *start, struct command **cmd) +{ + char *end; + + // Detect end of line (and truncate line at comment) + if (CFG_TOYSH_PIPES && strchr("><&|(;", *start)) return 0; + + // Grab next word. (Add dequote and envvar logic here) + end = start; + while (*end && !isspace(*end)) end++; + (*cmd)->argv[(*cmd)->argc++] = xstrndup(start, end-start); + + // Allocate more space if there's no room for NULL terminator. + + if (!((*cmd)->argc & 7)) + *cmd=xrealloc(*cmd, + sizeof(struct command) + ((*cmd)->argc+8)*sizeof(char *)); + (*cmd)->argv[(*cmd)->argc] = 0; + return end; +} + +// Parse a line of text into a pipeline. +// Returns a pointer to the next line. + +static char *parse_pipeline(char *cmdline, struct pipeline *line) +{ + struct command **cmd = &(line->cmd); + char *start = line->cmdline = cmdline; + + if (!cmdline) return 0; + + if (CFG_TOYSH_JOBCTL) line->cmdline = cmdline; + + // Parse command into argv[] + for (;;) { + char *end; + + // Skip leading whitespace and detect end of line. + while (isspace(*start)) start++; + if (!*start || *start=='#') { + if (CFG_TOYSH_JOBCTL) line->cmdlinelen = start-cmdline; + return 0; + } + + // Allocate next command structure if necessary + if (!*cmd) *cmd = xzalloc(sizeof(struct command)+8*sizeof(char *)); + + // Parse next argument and add the results to argv[] + end = parse_word(start, cmd); + + // If we hit the end of this command, how did it end? + if (!end) { + if (CFG_TOYSH_PIPES && *start) { + if (*start==';') { + start++; + break; + } + // handle | & < > >> << || && + } + break; + } + start = end; + } + + if (CFG_TOYSH_JOBCTL) line->cmdlinelen = start-cmdline; + + return start; +} + +// Execute the commands in a pipeline +static void run_pipeline(struct pipeline *line) +{ + struct toy_list *tl; + struct command *cmd = line->cmd; + if (!cmd || !cmd->argc) return; + + tl = toy_find(cmd->argv[0]); + // Is this command a builtin that should run in this process? + if (tl && (tl->flags & TOYFLAG_NOFORK)) { + struct toy_context temp; + + // This fakes lots of what toybox_main() does. + memcpy(&temp, &toys, sizeof(struct toy_context)); + memset(&toys, 0, sizeof(struct toy_context)); + toy_init(tl, cmd->argv); + tl->toy_main(); + cmd->pid = toys.exitval; + free(toys.optargs); + if (toys.old_umask) umask(toys.old_umask); + memcpy(&toys, &temp, sizeof(struct toy_context)); + } else { + int status; + + cmd->pid = vfork(); + if (!cmd->pid) xexec(cmd->argv); + else waitpid(cmd->pid, &status, 0); + + if (CFG_TOYSH_FLOWCTL || CFG_TOYSH_PIPES) { + if (WIFEXITED(status)) cmd->pid = WEXITSTATUS(status); + if (WIFSIGNALED(status)) cmd->pid = WTERMSIG(status); + } + } + + return; +} + +// Free the contents of a command structure +static void free_cmd(void *data) +{ + struct command *cmd=(struct command *)data; + + while(cmd->argc) free(cmd->argv[--cmd->argc]); +} + + +// Parse a command line and do what it says to do. +static void handle(char *command) +{ + struct pipeline line; + char *start = command; + + // Loop through commands in this line + + for (;;) { + + // Parse a group of connected commands + + memset(&line,0,sizeof(struct pipeline)); + start = parse_pipeline(start, &line); + if (!line.cmd) break; + + // Run those commands + + run_pipeline(&line); + llist_traverse(line.cmd, free_cmd); + } +} + +void cd_main(void) +{ + char *dest = *toys.optargs ? *toys.optargs : getenv("HOME"); + xchdir(dest); +} + +void exit_main(void) +{ + exit(*toys.optargs ? atoi(*toys.optargs) : 0); +} + +void sh_main(void) +{ + FILE *f; + + // Set up signal handlers and grab control of this tty. + if (CFG_TOYSH_TTY) { + if (isatty(0)) toys.optflags |= 1; + } + f = *toys.optargs ? xfopen(*toys.optargs, "r") : NULL; + if (TT.command) handle(TT.command); + else { + size_t cmdlen = 0; + for (;;) { + char *command = 0; + if (!f) xputc('$'); + if (1 > getline(&command, &cmdlen, f ? f : stdin)) break; + handle(command); + free(command); + } + } + + toys.exitval = 1; +} |