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authorSamuel Holland <samuel@sholland.org>2018-01-14 22:09:08 -0600
committerSamuel Holland <samuel@sholland.org>2018-01-15 00:02:54 -0600
commit810f46ab1cc801e54fc3836c22b5f1364cd632e6 (patch)
tree50a496ceecfec1585ce332685e7491313dd022b3
parent18ce7cc13e00f98e214c211b55669e8dd4b3268c (diff)
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pwd: Fully implement fgetpwent_r/getpwent_r
These functions require a deep copy of the structure into the caller-provided buffer. Also make sure to store NULL in result on error. Use the stream to differentiate the two functions and avoid duplication. Signed-off-by: Samuel Holland <samuel@sholland.org>
-rw-r--r--libgcompat/pwd.c119
1 files changed, 74 insertions, 45 deletions
diff --git a/libgcompat/pwd.c b/libgcompat/pwd.c
index 50d8da0..34c5d7b 100644
--- a/libgcompat/pwd.c
+++ b/libgcompat/pwd.c
@@ -1,63 +1,92 @@
/* some musl versions incorrectly mark fgetpwent() as a GNU extension */
#define _GNU_SOURCE
+#include <assert.h> /* assert */
+#include <errno.h> /* ENOENT, ERANGE */
+#include <pthread.h> /* pthread_mutex_* */
+#include <pwd.h> /* fgetpwent, getpwent, struct passwd */
+#include <stddef.h> /* NULL, size_t */
+#include <stdio.h> /* FILE */
+#include <string.h> /* memcpy, stpcpy, strlcpy, strlen */
-#include <errno.h>
-#include <pwd.h>
-#include <stdio.h>
-#include <string.h>
+static pthread_mutex_t pwent_mutex = PTHREAD_MUTEX_INITIALIZER;
-int getpwent_r(struct passwd *pwbuf, char *buf, size_t buflen,
- struct passwd **pwbufp)
+static int __fgetpwent_r(FILE *stream, struct passwd *pwd, char *buf,
+ size_t len, struct passwd **result)
{
- struct passwd *pwd;
+ struct passwd *pwtmp;
+ char *cursor = buf, *end = buf + len;
- if (pwbufp == NULL || pwbuf == NULL) {
- return ERANGE;
+ *result = NULL;
+ pthread_mutex_lock(&pwent_mutex);
+ pwtmp = stream != NULL ? fgetpwent(stream) : getpwent();
+ if (pwtmp == NULL) {
+ pthread_mutex_unlock(&pwent_mutex);
+ return ENOENT;
}
-
- if (buflen < 1) {
- return ERANGE;
+ memcpy(pwd, pwtmp, sizeof(*pwd));
+ if (pwtmp->pw_name != NULL) {
+ pwd->pw_name = cursor;
+ cursor += strlcpy(cursor, pwtmp->pw_name, end - cursor) + 1;
+ if (cursor > end) {
+ goto err_unlock;
+ }
}
-
- if (buf != NULL) {
- *buf = '\0';
+ if (pwtmp->pw_passwd != NULL) {
+ pwd->pw_passwd = cursor;
+ cursor += strlcpy(cursor, pwtmp->pw_passwd, end - cursor) + 1;
+ if (cursor > end) {
+ goto err_unlock;
+ }
}
-
- if ((pwd = getpwent()) == NULL) {
- *pwbufp = NULL;
- return ENOENT;
+ if (pwtmp->pw_gecos != NULL) {
+ pwd->pw_gecos = cursor;
+ cursor += strlcpy(cursor, pwtmp->pw_gecos, end - cursor) + 1;
+ if (cursor > end) {
+ goto err_unlock;
+ }
}
-
- memcpy(pwbuf, pwd, sizeof(*pwd));
- *pwbufp = pwbuf;
+ if (pwtmp->pw_dir != NULL) {
+ pwd->pw_dir = cursor;
+ cursor += strlcpy(cursor, pwtmp->pw_dir, end - cursor) + 1;
+ if (cursor > end) {
+ goto err_unlock;
+ }
+ }
+ if (pwtmp->pw_shell != NULL) {
+ pwd->pw_shell = cursor;
+ cursor += strlcpy(cursor, pwtmp->pw_shell, end - cursor) + 1;
+ if (cursor > end) {
+ goto err_unlock;
+ }
+ }
+ pthread_mutex_unlock(&pwent_mutex);
+ *result = pwd;
return 0;
+
+err_unlock:
+ pthread_mutex_unlock(&pwent_mutex);
+ return ERANGE;
}
-int fgetpwent_r(FILE *filp, struct passwd *pwbuf, char *buf, size_t buflen,
- struct passwd **pwbufp)
+/**
+ * Get passwd file entry.
+ */
+int fgetpwent_r(FILE *stream, struct passwd *pwd, char *buf, size_t len,
+ struct passwd **result)
{
- struct passwd *pwd;
-
- if (pwbufp == NULL || pwbuf == NULL) {
- return ERANGE;
- }
+ assert(stream != NULL);
- if (buflen < 1) {
- return ERANGE;
- }
-
- if (buf != NULL) {
- *buf = '\0';
- }
-
- if ((pwd = fgetpwent(filp)) == NULL) {
- *pwbufp = NULL;
- return ENOENT;
- }
-
- memcpy(pwbuf, pwd, sizeof(*pwd));
- *pwbufp = pwbuf;
+ return fgetpwent_r(stream, pwd, buf, len, result);
+}
- return 0;
+/**
+ * Get user database entry.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib-getpwent-r-1.html
+ */
+int getpwent_r(struct passwd *pwd, char *buf, size_t len,
+ struct passwd **result)
+{
+ return __fgetpwent_r(NULL, pwd, buf, len, result);
}