From 12780c8eb03e9f24470f5c9fa00cb5ac11af4160 Mon Sep 17 00:00:00 2001 From: Jonas 'Sortie' Termansen Date: Fri, 28 Feb 2014 22:46:58 +0100 Subject: [PATCH] Add env(1). --- doc/user-guide | 1 + utils/.gitignore | 1 + utils/Makefile | 1 + utils/env.cpp | 209 +++++++++++++++++++++++++++++++++++++++++++++++ utils/sh.cpp | 7 -- 5 files changed, 212 insertions(+), 7 deletions(-) create mode 100644 utils/env.cpp diff --git a/doc/user-guide b/doc/user-guide index 8141abd5..6118d3b8 100644 --- a/doc/user-guide +++ b/doc/user-guide @@ -157,6 +157,7 @@ Sortix comes with a number of home-made programs. Here is an overview: * `du` - report file and directory disk usage * `echo` - print command line arguments * `editor` - text editor +* `env` - run a program in a modified environment * `extfs` - ext2 filesystem server * `false` - exit with an error status * `find` - recursively list files diff --git a/utils/.gitignore b/utils/.gitignore index 770ccb9c..b75d749f 100644 --- a/utils/.gitignore +++ b/utils/.gitignore @@ -12,6 +12,7 @@ date du echo editor +env false find head diff --git a/utils/Makefile b/utils/Makefile index 004b07b9..4429779f 100644 --- a/utils/Makefile +++ b/utils/Makefile @@ -28,6 +28,7 @@ date \ du \ echo \ editor \ +env \ false \ find \ head \ diff --git a/utils/env.cpp b/utils/env.cpp new file mode 100644 index 00000000..75d44d1a --- /dev/null +++ b/utils/env.cpp @@ -0,0 +1,209 @@ +/******************************************************************************* + + Copyright(C) Jonas 'Sortie' Termansen 2014. + + This program is free software: you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by the Free + Software Foundation, either version 3 of the License, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + more details. + + You should have received a copy of the GNU General Public License along with + this program. If not, see . + + env.cpp + Set the environment for command invocation. + +*******************************************************************************/ + +#include +#include +#include +#include +#include +#include + +void clean_environment() +{ + while ( environ[0] ) + { + size_t equal_pos = strcspn(environ[0], "="); + if ( environ[0][equal_pos] != '=' ) + error(125, 0, "Bad Environment"); + char* key = strndup(environ[0], equal_pos); + if ( !key ) + error(125, errno, "strndup"); + if ( unsetenv(key) != 0 ) + error(125, errno, "cannot unset `%s'", key); + free(key); + } +} + +static void compact_arguments(int* argc, char*** argv) +{ + for ( int i = 0; i < *argc; i++ ) + { + while ( i < *argc && !(*argv)[i] ) + { + for ( int n = i; n < *argc; n++ ) + (*argv)[n] = (*argv)[n+1]; + (*argc)--; + } + } +} + +static void help(FILE* fp, const char* argv0) +{ + fprintf(fp, "Usage: %s [OPTION]... [-] [NAME=VALUE]... [COMMAND [ARG]...]\n", argv0); + fprintf(fp, "Set each NAME to VALUE in the environment and run COMMAND.\n"); + fprintf(fp, "\n"); + fprintf(fp, " -i, --ignore-environment start with an empty environment\n"); + fprintf(fp, " -0, --null end each output line with 0 byte rather than newline\n"); + fprintf(fp, " -u, --unset=NAME remove variable from the environment\n"); + fprintf(fp, " --help display this help and exit\n"); + fprintf(fp, " --version output version information and exit\n"); + fprintf(fp, "\n"); + fprintf(fp, "A mere - implies -i. If no COMMAND, print the resulting environment.\n"); +} + +static void version(FILE* fp, const char* argv0) +{ + fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR); + fprintf(fp, "License GPLv3+: GNU GPL version 3 or later .\n"); + fprintf(fp, "This is free software: you are free to change and redistribute it.\n"); + fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n"); +} + +int main(int argc, char* argv[]) +{ + bool ignore_environment = false; + bool null_terminate = false; + + const char* argv0 = argv[0]; + for ( int i = 1; i < argc; i++ ) + { + const char* arg = argv[i]; + if ( arg[0] != '-' ) + break; + if ( arg[0] == '-' && !arg[1] ) + { + ignore_environment = true; + break; + } + argv[i] = NULL; + if ( !strcmp(arg, "--") ) + break; + if ( arg[1] != '-' ) + { + while ( char c = *++arg ) switch ( c ) + { + case 'i': ignore_environment = true; break; + case 'u': + if ( !arg[1] ) + { + if ( i + 1 == argc ) + { + error(0, 0, "option requires an argument -- 'u'"); + fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]); + exit(125); + } + const char* key = argv[i+1]; + argv[++i] = NULL; + if ( unsetenv(key) != 0 ) + error(125, errno, "cannot unset `%s'", key); + } + else + { + const char* key = arg + 1; + if ( unsetenv(key) != 0 ) + error(125, errno, "cannot unset `%s'", key); + } + arg = "u"; + break; + case '0': null_terminate = true; break; + default: + fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c); + help(stderr, argv0); + exit(1); + } + } + else if ( !strcmp(arg, "--help") ) + help(stdout, argv0), exit(0); + else if ( !strcmp(arg, "--version") ) + version(stdout, argv0), exit(0); + else if ( !strcmp(arg, "--ignore-environment") ) + ignore_environment = true; + else if ( !strcmp(arg, "--null") ) + null_terminate = true; + else if ( !strncmp(arg, "--unset=", strlen("--unset=")) ) + { + const char* key = arg + strlen("--unset="); + if ( unsetenv(key) != 0 ) + error(125, errno, "cannot unset `%s'", key); + } + else if ( !strcmp(arg, "--unset") ) + { + if ( i + 1 == argc ) + { + error(0, 0, "option '--unset' requires an argument"); + fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]); + exit(125); + } + const char* key = argv[i+1]; + argv[++i] = NULL; + if ( unsetenv(key) != 0 ) + error(125, errno, "cannot unset `%s'", key); + } + else + { + fprintf(stderr, "%s: unknown option: %s\n", argv0, arg); + help(stderr, argv0); + exit(1); + } + } + + if ( ignore_environment ) + clean_environment(); + + compact_arguments(&argc, &argv); + + for ( int i = 1; i < argc; i++ ) + { + char* arg = argv[i]; + size_t equal_pos = strcspn(arg, "="); + if ( arg[equal_pos] != '=' ) + break; + argv[i] = NULL; + arg[equal_pos] = '\0'; + const char* key = arg; + const char* value = arg + equal_pos + 1; + if ( setenv(key, value, 1) != 0 ) + error(125, errno, "setenv(\"%s\", \"%s\")", key, value); + } + + compact_arguments(&argc, &argv); + + if ( argc == 1 ) + { + for ( size_t i = 0; environ[i]; i++ ) + { + fputs(environ[i], stdout); + fputc(null_terminate ? '\0' : '\n', stdout); + } + return 0; + } + + if ( null_terminate ) + { + error(0, 0, "cannot specify --null (-0) with command"); + fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]); + exit(125); + } + + execvp(argv[1], argv + 1); + error(errno == ENOENT ? 127 : 126, errno, "%s", argv[1]); +} diff --git a/utils/sh.cpp b/utils/sh.cpp index f55d1221..a88e9757 100644 --- a/utils/sh.cpp +++ b/utils/sh.cpp @@ -339,13 +339,6 @@ readcmd: } } - if ( !strcmp(argv[0], "env") ) - { - for ( size_t i = 0; environ[i]; i++ ) - printf("%s\n", environ[i]); - exit(0); - } - execvp(argv[0], argv); if ( interactive ) {