env exists is a way to test (in hush) if an environment variable exists. A workaround existed using printenv but this new command doesn't require all the stdout/stderr redirection to prevent printing information to the screen.
Example: $ set testexists 1 $ env exists testexists && echo "yes" yes $ env exists testexists || echo "no" $ set testexists $ env exists testexists && echo "yes" $ env exists testexists || echo "no" no $
Signed-off-by: Andrew Ruder andrew.ruder@elecsyscorp.com --- README | 1 + common/cmd_nvedit.c | 23 +++++++++++++++++++++++ 2 files changed, 24 insertions(+)
diff --git a/README b/README index 09662a4..0718459 100644 --- a/README +++ b/README @@ -843,6 +843,7 @@ The following options need to be configured: CONFIG_CMD_ELF * bootelf, bootvx CONFIG_CMD_ENV_CALLBACK * display details about env callbacks CONFIG_CMD_ENV_FLAGS * display details about env flags + CONFIG_CMD_ENV_EXISTS * check existence of env variable CONFIG_CMD_EXPORTENV * export the environment CONFIG_CMD_EXT2 * ext2 command support CONFIG_CMD_EXT4 * ext4 command support diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c index ba9ba16..0d4d02c 100644 --- a/common/cmd_nvedit.c +++ b/common/cmd_nvedit.c @@ -1059,6 +1059,23 @@ sep_err: } #endif
+#if defined(CONFIG_CMD_ENV_EXISTS) +static int do_env_exists(cmd_tbl_t *cmdtp, int flag, int argc, + char * const argv[]) +{ + ENTRY e, *ep; + + if (argc < 2) + return CMD_RET_USAGE; + + e.key = argv[1]; + e.data = NULL; + hsearch_r(e, FIND, &ep, &env_htab, 0); + + return (ep == NULL) ? 1 : 0; +} +#endif + /* * New command line interface: "env" command with subcommands */ @@ -1094,6 +1111,9 @@ static cmd_tbl_t cmd_env_sub[] = { U_BOOT_CMD_MKENT(save, 1, 0, do_env_save, "", ""), #endif U_BOOT_CMD_MKENT(set, CONFIG_SYS_MAXARGS, 0, do_env_set, "", ""), +#if defined(CONFIG_CMD_ENV_EXISTS) + U_BOOT_CMD_MKENT(exists, 2, 0, do_env_exists, "", ""), +#endif };
#if defined(CONFIG_NEEDS_MANUAL_RELOC) @@ -1136,6 +1156,9 @@ static char env_help_text[] = #if defined(CONFIG_CMD_EDITENV) "env edit name - edit environment variable\n" #endif +#if defined(CONFIG_CMD_ENV_EXISTS) + "env exists name - tests for existence of variable\n" +#endif #if defined(CONFIG_CMD_EXPORTENV) "env export [-t | -b | -c] [-s size] addr [var ...] - export environment\n" #endif