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commit 92c3b6446d6cb8c99002cc3d376e040f9cb93fde Author: Abhishek Mishra <[email protected]> AuthorDate: Thu Jul 16 18:55:50 2026 +0000 nsh: show real, effective, and saved IDs in id command Use getresuid() and getresgid() for Linux-style id output with name resolution and a groups= list based on the effective GID. Signed-off-by: Abhishek Mishra <[email protected]> --- nshlib/nsh_identity.c | 213 ++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 207 insertions(+), 6 deletions(-) diff --git a/nshlib/nsh_identity.c b/nshlib/nsh_identity.c index 7bcb9a4a0..6d9e6160f 100644 --- a/nshlib/nsh_identity.c +++ b/nshlib/nsh_identity.c @@ -27,6 +27,7 @@ #include <nuttx/config.h> #include <errno.h> +#include <grp.h> #include <pwd.h> #include <stdio.h> #include <stdbool.h> @@ -381,28 +382,228 @@ int cmd_su(FAR struct nsh_vtbl_s *vtbl, int argc, FAR char **argv) } #endif +#ifndef CONFIG_NSH_DISABLE_ID + +/**************************************************************************** + * Name: nsh_id_format_uid + * + * Description: + * Format a UID token in Linux id(1) style, e.g. "uid=0(root)". + * + ****************************************************************************/ + +static void nsh_id_format_uid(FAR char *buf, size_t buflen, + FAR const char *tag, uid_t uid) +{ +#ifdef CONFIG_LIBC_PASSWD_FILE + FAR struct passwd *pwd = getpwuid(uid); + + if (pwd != NULL && pwd->pw_name != NULL) + { + snprintf(buf, buflen, "%s=%d(%s)", tag, uid, pwd->pw_name); + return; + } +#endif + + if (uid == 0) + { + snprintf(buf, buflen, "%s=%d(root)", tag, uid); + } + else + { + snprintf(buf, buflen, "%s=%d", tag, uid); + } +} + +/**************************************************************************** + * Name: nsh_id_format_gid + * + * Description: + * Format a GID token in Linux id(1) style, e.g. "gid=0(root)". + * + ****************************************************************************/ + +static void nsh_id_format_gid(FAR char *buf, size_t buflen, + FAR const char *tag, gid_t gid) +{ +#ifdef CONFIG_LIBC_GROUP_FILE + FAR struct group *grp = getgrgid(gid); + + if (grp != NULL && grp->gr_name != NULL) + { + snprintf(buf, buflen, "%s=%d(%s)", tag, gid, grp->gr_name); + return; + } +#endif + + if (gid == 0) + { + snprintf(buf, buflen, "%s=%d(root)", tag, gid); + } + else + { + snprintf(buf, buflen, "%s=%d", tag, gid); + } +} + +static void nsh_id_append(FAR char *line, size_t linelen, + FAR const char *token) +{ + size_t len = strlen(line); + + if (len > 0) + { + strlcat(line, " ", linelen); + } + + strlcat(line, token, linelen); +} + +#ifdef CONFIG_LIBC_PASSWD_FILE +/**************************************************************************** + * Name: nsh_id_format_group_value + * + * Description: + * Format a bare group value for a groups= list, e.g. "0(root)". + * + ****************************************************************************/ + +static void nsh_id_format_group_value(FAR char *buf, size_t buflen, + gid_t gid) +{ +#ifdef CONFIG_LIBC_GROUP_FILE + FAR struct group *grp = getgrgid(gid); + + if (grp != NULL && grp->gr_name != NULL) + { + snprintf(buf, buflen, "%d(%s)", gid, grp->gr_name); + return; + } +#endif + + if (gid == 0) + { + snprintf(buf, buflen, "0(root)"); + } + else + { + snprintf(buf, buflen, "%d", gid); + } +} + +/**************************************************************************** + * Name: nsh_id_append_groups + * + * Description: + * Append a Linux-style groups= list to the id output line. + * + ****************************************************************************/ + +static void nsh_id_append_groups(FAR char *line, size_t linelen) +{ + gid_t grouplist[8]; + char token[48]; + int ngroups; + int i; + + ngroups = getgroups(sizeof(grouplist) / sizeof(grouplist[0]), grouplist); + if (ngroups <= 0) + { + return; + } + + strlcat(line, " groups=", linelen); + + for (i = 0; i < ngroups; i++) + { + if (i > 0) + { + strlcat(line, ",", linelen); + } + + nsh_id_format_group_value(token, sizeof(token), grouplist[i]); + strlcat(line, token, linelen); + } +} +#endif /* CONFIG_LIBC_PASSWD_FILE */ + /**************************************************************************** * Name: cmd_id * * Description: - * Print real and effective UID/GID for the current session. + * Print real, effective, and saved-set UID/GID for the current session in + * Linux id(1) style with optional user and group names. * ****************************************************************************/ -#ifndef CONFIG_NSH_DISABLE_ID int cmd_id(FAR struct nsh_vtbl_s *vtbl, int argc, FAR char **argv) { + uid_t ruid; + uid_t euid; + uid_t suid; + gid_t rgid; + gid_t egid; + gid_t sgid; + char line[256]; + char token[48]; + if (argc != 1) { nsh_error(vtbl, g_fmtarginvalid, argv[0]); return ERROR; } - nsh_output(vtbl, "uid=%d euid=%d gid=%d egid=%d\n", - getuid(), geteuid(), getgid(), getegid()); + if (getresuid(&ruid, &euid, &suid) != 0) + { + nsh_error(vtbl, "id: getresuid() failed: %d\n", errno); + return ERROR; + } + + if (getresgid(&rgid, &egid, &sgid) != 0) + { + nsh_error(vtbl, "id: getresgid() failed: %d\n", errno); + return ERROR; + } + + line[0] = '\0'; + + nsh_id_format_uid(token, sizeof(token), "uid", ruid); + nsh_id_append(line, sizeof(line), token); + + if (euid != ruid) + { + nsh_id_format_uid(token, sizeof(token), "euid", euid); + nsh_id_append(line, sizeof(line), token); + } + + if (suid != ruid && suid != euid) + { + nsh_id_format_uid(token, sizeof(token), "suid", suid); + nsh_id_append(line, sizeof(line), token); + } + + nsh_id_format_gid(token, sizeof(token), "gid", rgid); + nsh_id_append(line, sizeof(line), token); + + if (egid != rgid) + { + nsh_id_format_gid(token, sizeof(token), "egid", egid); + nsh_id_append(line, sizeof(line), token); + } + + if (sgid != rgid && sgid != egid) + { + nsh_id_format_gid(token, sizeof(token), "sgid", sgid); + nsh_id_append(line, sizeof(line), token); + } + +#ifdef CONFIG_LIBC_PASSWD_FILE + nsh_id_append_groups(line, sizeof(line)); +#endif + nsh_output(vtbl, "%s\n", line); return OK; } -#endif +#endif /* CONFIG_NSH_DISABLE_ID */ /**************************************************************************** * Name: cmd_whoami @@ -442,7 +643,7 @@ int cmd_whoami(FAR struct nsh_vtbl_s *vtbl, int argc, FAR char **argv) } else { - nsh_output(vtbl, "%d\n", (int)euid); + nsh_output(vtbl, "%d\n", euid); } return OK;
